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3 Mailutils Programs

GNU Mailutils provides a broad set of utilities for handling electronic mail. These utilities address the needs of both system administrators and users.

All utilities are built around a single core subsystem and share many common aspects. All of them are able to work with almost any existing mailbox formats. They use a common configuration file syntax, and their configuration files are located in a single subdirectory.

In this chapter we will discuss each utility, and give some advices on how to use them in various real life situations.

First of all we will describe command line and configuration file syntax.

3.1 Command Line

3.1.1 Basic Notions About Command Line Options

Many command line options have two forms, called short and long forms. Both forms are absolutely identical in function; they are interchangeable.

The short form is a traditional form for UNIX utilities. In this form, the option consists of a single dash, followed by a single letter, e.g. -c.

Short options which require arguments take their arguments immediately following the option letter, optionally separated by white space. For example, you might write -f name, or -fname. Here, -f is the option, and name is its argument.

Short options which allow optional arguments take their arguments immediately following the option letter, without any intervening white space characters. This is important, so that the command line parser might discern that the text following option is its argument, not the next command line parameter. For example, if option -d took an optional argument, then -dname would mean the option with its argument (name in this case), and -d name would mean the -d option without any argument, followed by command line argument name.

Short options’ letters may be clumped together, but you are not required to do this. When short options are clumped as a set, use one (single) dash for them all, e.g. -cvl is equivalent to -c -v -l. However, only options that do not take arguments may be clustered this way. If an option takes an argument, it can only be the last option in such a cluster, otherwise it would be impossible to specify the argument for it. Anyway, it is much more readable to specify such options separated.

The long option names are probably easier to memorize than their short counterparts. They consist of two dashes, followed by a multi-letter option name, which is usually selected to be a mnemonics for the operation it requests. For example, --verbose is a long option that increases the verbosity of a utility. In addition, long option names can abbreviated, provided that such an abbreviation is unique among the options understood by a given utility. For example, if a utility takes options --foreground and --forward, then the shortest possible abbreviations for these options are --fore and --forw, correspondingly. If you try to use --for, the utility will abort and inform you that the abbreviation you use is ambiguous, so it is not clear which of the options you intended to use.

Long options which require arguments take those arguments following the option name. There are two ways of specifying a mandatory argument. It can be separated from the option name either by an equal sign, or by any amount of white space characters. For example, if the --file option requires an argument, and you wish to supply name as its argument, then you can do so using any of the following notations: --file=name or --file name.

In contrast, optional arguments must always be introduced using an equal sign.

3.1.2 Options That are Common for All Utilities.

All GNU Mailutils programs understand a common subset of options.

--help
-?

Display a short summary of the command line options understood by this utilities, along with a terse description of each.

The output of this option consists of three major parts. First, a usage synopsis is displayed. For example:

Usage: sieve [OPTION...] SCRIPT
GNU sieve -- a mail filtering tool

The first line tells that the sieve utility takes any number of options (brackets indicate optional part) and a single mandatory argument (‘SCRIPT’). The second lines summarizes the purpose of the utility.

Following this header is an option summary. It consists of two columns:

  -c, --compile-only         Compile script and exit
  -d, --debug[=FLAGS]        Debug flags
  -e, --email=ADDRESS        Override user email address

The leftmost column contains a comma-separated list of option names. Short options are listed first. The options are ordered alphabetically. Arguments, if any, are specified after the last option name in the list, so that, e.g. the option ‘-e’ in the example above requires an argument: ‘-e ADDRESS’. Optional arguments are enclosed in square brackets, as in --debug option in the example above.

The rightmost column contains a short description of the option purpose.

The last part of --help output contains some additional notices and lists the email address for reporting bugs.

--usage

Display a short summary of options. In the contrast to the --help option, only option names and arguments are printed, without any textual description. For example:

Usage: sieve [-cv?V] [--compile-only] [--debug[=FLAGS]]
             [--email=ADDRESS] SCRIPT

The exact formatting of the output produced by these two options is configurable. See Usage Vars, for a detailed descriptions of it.

--version
-V

Print program version and exit.

--show-config-options

Show configuration options used when compiling the package. You can use this option to verify if support for a particular mailbox format or other functionality is compiled in the binary. The output of this option is intended to be both machine-readable and understandable by humans.

The following command line options affect parsing of configuration files. Here we provide a short summary, the next section will describe them in detail.

--config-file=file

Load this configuration file, instead of the default.

--config-help

Show configuration file summary.

--config-lint

Check configuration file syntax and exit

--config-verbose

Verbosely log parsing of the configuration files.

--no-site-config

Do not load site-wide configuration file.

--no-user-config

Do not load user configuration file.

--no-config

Don’t load site-wide and user configuration files.

--set=path=value

Set configuration variable. See the --set option.

3.2 Mailutils Configuration File

Configuration files are the principal means of configuring any GNU Mailutils component. When started, each utility tries to load its configuration from the following locations, in that order:

  1. Main site-wide configuration file.

    It is named sysconfdir/mailutils.conf, where sysconfdir stands for the system configuration directory set when compiling the package. You can obtain the value of sysconfdir by running

    $ mailutils info sysconfdir
    

    or

    $ prog --show-config-options | grep SYSCONFDIR
    

    where prog stands for any GNU Mailutils utility.

    The site-wide configuration file is not read if any of --no-site-config or --no-config command line options was given.

    Older versions of GNU Mailutils read configuration from file mailutils.rc. To facilitate transition, mailutils will look for that file as well. If both the default site-wide configuration file and legacy configuration file are present you will get the following warning:

    legacy configuration file /etc/mailutils.rc ignored
    

    Otherwise, if mailutils.conf does not exist and mailutils.rc is present, it will be used instead and the following warning will be issued:

     using legacy configuration file /etc/mailutils.rc:
     please rename it to /etc/mailutils.conf
    
  2. Per-user configuration file.

    Client utilities, such as frm or sieve, look in the user home directory for a file named ‘.prog’, where prog is the name of the utility. If present, this file will be loaded after loading the site-wide configuration file. For example, the per-user configuration file for sieve utility is named .sieve.

    Loading of per-user configuration file is disabled by --no-user-config and --no-config options.

Server programs, such as imap4d don’t use per-user configuration files.

The --no-config option provides a shortcut for disabling loading of the default configuration files. For servers, its effect is the same as of --no-site-config. For client utilities, it is equivalent to --no-site-config --no-user-config used together.

The --config-file command line option instructs the program to read configuration from the file supplied as its argument. In that case, default configuration files are not used at all.

Neither site-wide nor user configuration files are required to exist. If any or both of them are absent, GNU Mailutils won’t complain – the utility will silently fall back to its default settings.

To make configuration processing more verbose, use the --config-verbose command line option. Here is an example of what you might get using this option:

imap4d: parsing file `/etc/mailutils.conf'
imap4d: finished parsing file `/etc/mailutils.conf'

Specifying this option more than once adds more verbosity to this output. If this option is given two times, GNU Mailutils will print each configuration file statement it parsed, along with the exact location where it occurred (the exact meaning of each statement will be described later in this chapter):

imap4d: parsing file `/etc/mailutils.conf'
# 1 "/etc/mailutils.conf"
mailbox {
# 2 "/etc/mailutils.conf"
  mailbox-pattern maildir:/var/spool/mail;type=index;param=2;user=${user};
# 3 "/etc/mailutils.conf"
  mailbox-type maildir;
};
# 6 "/etc/mailutils.conf"
include /etc/mailutils.d;
imap4d: parsing file `/etc/mailutils.d/imap4d'
...

To test configuration file without actually running the utility, use the --config-lint command line option. With this option, any Mailutils utility exits after finishing parsing of the configuration files. Any errors occurred during parsing are displayed on the standard error output. This option can be combined with --config-verbose to obtain more detailed output.

The --config-help command line option produces on the standard output the summary of all configuration statements understood by the utility, with detailed comments and in the form suitable for configuration file. For example, the simplest way to write a configuration file for, say, imap4d is to run

$ imap4d --config-help > imap4d.conf

and to edit the imap4d.conf file with your editor of choice.

The order in which configuration files are loaded defines the precedence of their settings. Thus, for client utilities, settings from the per-user configuration file override those from the site-wide configuration.

It is also possible to set or override arbitrary configuration variables in the command line. It can be done via the --set option. Its argument is a pathname of the variable to be set, followed by an equals sign and a value. For example, to define the variable ‘syslog’ in section ‘logging’ to ‘no’, do the following:

$ imap4d --set .logging.syslog=no

Configuration pathnames are discussed in detail in Paths. For a detailed description of this option, the --set option.

The --set options are processed after loading all configuration files.

3.2.1 Configuration File Syntax

The configuration file consists of statements and comments.

There are three classes of lexical tokens: keywords, values, and separators. Blanks, tabs, newlines and comments, collectively called white space are ignored except as they serve to separate tokens. Some white space is required to separate otherwise adjacent keywords and values.

3.2.1.1 Comments

Comments may appear anywhere where white space may appear in the configuration file. There are two kinds of comments: single-line and multi-line comments. Single-line comments start with ‘#’ or ‘//’ and continue to the end of the line:

# This is a comment
// This too is a comment

Multi-line or C-style comments start with the two characters ‘/*’ (slash, star) and continue until the first occurrence of ‘*/’ (star, slash).

Multi-line comments cannot be nested. However, single-line comments may well appear within multi-line ones.

3.2.1.2 Statements

A simple statement consists of a keyword and value separated by any amount of whitespace. Simple statement is terminated with a semicolon (‘;’).

The following is a simple statement:

standalone yes;
pidfile /var/run/pop3d.pid;

A keyword begins with a letter and may contain letters, decimal digits, underscores (‘_’) and dashes (‘-’). Examples of keywords are: ‘expression’, ‘output-file’.

A value can be one of the following:

number

A number is a sequence of decimal digits.

boolean

A boolean value is one of the following: ‘yes’, ‘true’, ‘t’ or ‘1’, meaning true, and ‘no’, ‘false’, ‘nil’, ‘0’ meaning false.

unquoted string

An unquoted string may contain letters, digits, and any of the following characters: ‘_’, ‘-’, ‘.’, ‘/’, ‘@’, ‘*’, ‘:’.

quoted string

A quoted string is any sequence of characters enclosed in double-quotes (‘"’). A backslash appearing within a quoted string introduces an escape sequence, which is replaced with a single character according to the following rules:

SequenceReplaced with
\aAudible bell character (ASCII 7)
\bBackspace character (ASCII 8)
\fForm-feed character (ASCII 12)
\nNewline character (ASCII 10)
\rCarriage return character (ASCII 13)
\tHorizontal tabulation character (ASCII 9)
\vVertical tabulation character (ASCII 11)
\\A single backslash (‘\’)
\"A double-quote.

Table 3.1: Backslash escapes

In addition, the sequence ‘\newline’ is removed from the string. This allows to split long strings over several physical lines, e.g.:

"a long string may be\
 split over several lines"

If the character following a backslash is not one of those specified above, the backslash is ignored and a warning is issued.

Two or more adjacent quoted strings are concatenated, which gives another way to split long strings over several lines to improve readability. The following fragment produces the same result as the example above:

"a long string may be"
" split over several lines"
Here-document

A here-document is a special construct that allows to introduce strings of text containing embedded newlines.

The <<word construct instructs the parser to read all the following lines up to the line containing only word, with possible trailing blanks. Any lines thus read are concatenated together into a single string. For example:

<<EOT
A multiline
string
EOT

The body of a here-document is interpreted the same way as a double-quoted string, unless word is preceded by a backslash (e.g. ‘<<\EOT’) or enclosed in double-quotes, in which case the text is read as is, without interpretation of escape sequences.

If word is prefixed with - (a dash), then all leading tab characters are stripped from input lines and the line containing word. Furthermore, if - is followed by a single space, all leading whitespace is stripped from them. This allows to indent here-documents in a natural fashion. For example:

<<- TEXT
    The leading whitespace will be
    ignored when reading these lines.
TEXT

It is important that the terminating delimiter be the only token on its line. The only exception to this rule is allowed if a here-document appears as the last element of a statement. In this case a semicolon can be placed on the same line with its terminating delimiter, as in:

help-text <<-EOT
        A sample help text.
EOT;
list

A list is a comma-separated list of values. Lists are enclosed in parentheses. The following example shows a statement whose value is a list of strings:

alias (test,null);

In any case where a list is appropriate, a single value is allowed without being a member of a list: it is equivalent to a list with a single member. This means that, e.g.

alias test;

is equivalent to

alias (test);

A block statement introduces a logical group of statements. It consists of a keyword, followed by an optional value, and a sequence of statements enclosed in curly braces, as shown in the example below:

server srv1 {
  host 10.0.0.1;
  community "foo";
}

The closing curly brace may be followed by a semicolon, although this is not required.

3.2.1.3 Statement Path

Mailutils configuration files have a distinct hierarchical structure. Each statement in such files can therefore be identified by its name and the names of block statements containing it. Such names form the pathname, similar to that used by UNIX file system.

For example, consider the following file:

foo {
  bar {
    baz 45;   # A.
  }
  baz 98;     # B.
}

The full pathname of the statement marked with ‘A’ can be written as:

.foo.bar.baz

Similarly, the statement marked with ‘B’ has the following pathname:

.foo.baz

The default path component separator is dot. A pathname beginning with a component separator is called absolute pathname. Absolute pathnames uniquely identify corresponding statements. If the leading dot is omitted, the resulting pathname is called relative. Relative pathnames identify statements in relation to the current point of reference in the configuration file.

Any other punctuation character can be used as a component separator, provided that it appears at the beginning of the pathname. In other words, only absolute pathnames allow for a change in component separators.

A block statement that has a tag is referred to by the statement’s name, followed by an equals sign, followed by the tag value. For example, the statement ‘A’ in the file below:

program x {
  bar {
    baz 45;   # A.
  }
}

is identified by the following pathname:

.program=x.bar.baz

The tag can optionally be enclosed in a pair of double quotes. Such a quoting becomes mandatory for tags that contain white space or path component separator, e.g.:

.program="a.out".bar.baz

The --set command line option allows you to set configuration variables from the command line. Its argument consists of the statement path and value, separated by a single equals sign (no whitespace is permitted at either side of it). For example, the following option:

--set .logging.facility=mail

has the same effect as the following statement in the configuration file:

logging {
    facility mail;
}

Values set using this option override those set in the configuration files. This provides a convenient way for temporarily changing configuration without altering configuration files.

Notice, that when using --set, the ‘=’ sign has two purposes: first it separates statement path from the value, thus forming an assignment, and secondly it can be used within the path itself to introduce a tag. To illustrate this, let’s assume you have the following statement in your configuration file:

program pop3d {
    logging {
       facility mail;
    }
    server 0.0.0.0 {
       transcript no;
    }
}

Now assume you wish to temporarily change logging facility to ‘local1’. The following option will do this:

--set .program=pop3d.logging.facility=local1

When splitting the argument to --set, the option parser always looks for the rightmost equals sign. Everything to the right of it is the value, and everything to the left of it - the path.

If the tag contains dots (as the server statement in the example above), you should either escape them with slashes or change the pathname separator to some other character, e.g.:

--set .program=pop3d.server='0\.0\.0\.0'.transcript=yes

or

--set /program=pop3d/server="0.0.0.0"/transcript=yes

3.2.2 Configuration Variables

Certain configuration statements allow for the use of variable references in their values. A variable reference has the form ‘$variable’ or ‘${variable}’, where variable is the variable name. It is expanded to the actual value of variable when Mailutils consults the configuration statement in question.

The two forms are entirely equivalent. The form with curly braces is normally used if the variable name is immediately followed by an alphanumeric symbol, which will otherwise be considered part of it. This form also allows for specifying the action to take if the variable is undefined or expands to an empty value.

During variable expansion, the forms below cause Mailutils to test for a variable that is unset or null. Omitting the colon results in a test only for a variable that is unset.

${variable:-word}

Use Default Values. If variable is unset or null, the expansion of word is substituted. Otherwise, the value of variable is substituted.

${variable:=word}

Assign Default Values. If variable is unset or null, the expansion of word is assigned to variable. The value of variable is then substituted.

${variable:?word}

Display Error if Null or Unset. If variable is null or unset, the expansion of word (or a message to that effect if word is not present) is output to the current logging channel. Otherwise, the value of variable is substituted.

${variable:+word}

Use Alternate Value. If variable is null or unset, nothing is substituted, otherwise the expansion of word is substituted.

When a value is subject to variable expansion, it is also subject to command expansion. Commands are invoked in string values using the following format:

$(cmd arg)

where cmd is the command name, and args is a list of arguments separated by whitespace. Arguments can in turn contain variable and command references.

The following commands are defined:

Command: localpart string

Treats string as an email address and returns the part preceding the ‘@’ sign. If there is no ‘@’ sign, returns string.

Command: domainpart string

Treats string as an email address and returns the part following the ‘@’ sign. If there is no ‘@’ sign, returns empty string.

Command: shell cmd args

Runs the shell command cmd with the given arguments. Returns the standard output from the command. The command is invoked using /bin/sh -c and can contain any valid shell constructs.

The subsections below define variable names that are valid for use in each configuration statement.

3.2.3 The include Statement

A special statement is provided that causes inclusion of the named file. It has the following syntax:

include file;

When reading the configuration file, this statement is effectively replaced with the content of file. It is an error if file does not exist.

In site-wide configuration file, file can be a directory name. In this case, Mailutils will search this directory for a file with the same name as the utility being executed. If found, this file will be loaded.

It is a common to end the site-wide configuration file with an include statement, e.g.:

include /etc/mailutils.d;

This allows each particular utility to have its own configuration file. Thus, imap4d will read /etc/mailutils.d/imap4d, etc.

3.2.4 The program statement

Another way to configure program-specific settings is by using the program statement. The syntax is as follows:

program progname {
   ...
}

The program statement is allowed only in the site-wide configuration file. When encountered, its tag (progname) is compared with the name of the program being run. If two strings are the same, the statements between curly braces are stored in a temporary memory, otherwise the statement is ignored. When entire configuration file is loaded, the statements accumulated in the temporary storage are processed.

Notice the difference between this statement and a per-program configuration file loaded via an include statement. No matter where in the file the program statement is, its content will be processed after the content of the enclosing file. In the contrast, the per-program configuration file loaded via include is processed right where it is encountered.

3.2.5 The logging Statement

Syntax

logging {
  # Send diagnostics to syslog.
  syslog boolean;
  
  # Print message severity levels.
  print-severity boolean;
  
  # Output only messages with a severity equal to or
  # greater than this one.
  severity string;
  
  # Set syslog facility.
  facility name;

  # Log session ID
  session-id boolean;
    
  # Tag syslog messages with this string.
  tag text;
}

Description

The logging block statement configures where the diagnostic output goes and how verbose it is.

Configuration: syslog bool

If ‘syslog’ is set to ‘yes’, the diagnostics will go to syslog. Otherwise, it goes to the standard error.

The default syslog facility is determined at compile time, it can be inspected using the following command (see mailutils info):

$ mailutils info log_facility
Configuration: facility name

Use syslog facility name. Valid argument values are: ‘user’, ‘daemon’, ‘auth’, ‘authpriv’, ‘mail’, ‘cron’, ‘local0’ through ‘local7’ (all names case-insensitive), or a facility number.

Configuration: tag text

Tag syslog messages with text. By default, program name is used as syslog tag.

Configuration: print-severity bool

Print Mailutils severity name before each message.

Configuration: severity name

Output only messages with a severity equal to or greater than this one. Valid arguments are: ‘debug’, ‘info’, ‘notice’, ‘warning’, ‘error’, ‘crit’, ‘alert’, ‘emerg’,

Configuration: session-id bool

Print session ID with each diagnostic message. This is useful for programs that handle multiple user sessions simultaneously, such as pop3d and imap4d.

3.2.6 The debug Statement

Syntax

debug {
  # Set Mailutils debugging level.
  level spec;
  
  # Prefix debug messages with Mailutils source locations.
  line-info bool;
}

Description

The ‘debug’ statement controls the amount of additional debugging information output by Mailutils programs. The ‘level’ statement enables additional debugging information. Its argument (spec) is a Mailutils debugging specification as described in debugging.

The ‘line-info’ statement, when set to ‘true’ causes debugging messages to be prefixed with locations in Mailutils source files where they appear. Normally, only Mailutils developers need this option.

3.2.7 The mailbox Statement

Syntax

mailbox {
  # Use specified url as a mailspool.
  mail-spool url;
  
  # Create mailbox url using pattern.
  mailbox-pattern pattern;
  
  # Default mailbox type.
  mailbox-type type;
  
  # Default user mail folder.
  folder dir;
}

Description

The mailbox statement configures the location, name and type of user mailboxes.

The mailbox location can be specified using mail-spool or mail-pattern statements.

Configuration: mail-spool path

The mail-spool statement specifies directory that holds user mailboxes. Once this statement is given, the libmailutils library will assume that the mailbox of user login is kept in file path/login.

Historically, path can contain mailbox type prefix, e.g.: ‘maildir:///var/spool/mail’, but such usage is discouraged in favor of mailbox-pattern statement.

Configuration: mailbox-pattern url

The mailbox-pattern statement is a preferred way of configuring mailbox locations. It supersedes mail-spool statement.

The url must be a valid mailbox URL (see Mailbox), which may contain references to the ‘user’ variable (see Variables). This variable will be expanded to the actual user name.

Optional URL parameters can be used to configure indexed directory structure. Such structure is a special way of storing mailboxes, which allows for faster access in case of very large number of users.

By default, all user mailboxes are stored in a single directory and are named after user login names. To find the mailbox for a given user, the system scans the directory for the corresponding file. This usually implies linear search, so the time needed to locate a mailbox is directly proportional to the ordinal number of the mailbox in the directory.

GNU Mailutils supports three types of indexed directories: ‘direct’, ‘reverse’, and ‘hashed’.

In direct indexed directory structure, path contains 26 subdirectories named with lower-case letters of Latin alphabet. The location of the user mailbox is determined using the following algorithm:

  1. Take the first letter of the user name.
  2. Map it to a lower-case letter using index mapping table. The result gives the name of a sub-directory where the mailbox is located.
  3. Descend into this directory.

For example, using this algorithm, the mailbox of the user ‘smith’ is stored in file path/s/smith.

If each of single-letter subdirectories contains the indexed directory structure, we have second level of indexing. In this case the file name of ‘smith’’s mailbox is path/s/m/smith.

The reverse indexed structure uses the same principles, but the indexing letters are taken from the end of the user name, instead of from the beginning. For example, in the 2nd level reverse indexed structure, the ‘smith’’s mailbox is located in path/h/t/smith.

Finally, the hashed structure consists of 256 subdirectories under path, named by 2-letter hex codes from ‘00’ to ‘FF’. Mailboxes are stored in these subdirectories. The name of the subdirectory is computed by hashing first level letters of the user name. The hashing algorithm is:

  1. Take next letter from the user name
  2. Add its ASCII value to the hash sum.
  3. Continue (1-2) until level letters are processed, or all letters from the file name are used, whichever occurs first.
  4. Convert the computed sum modulo 256 to a hex code.

Indexed directory structures are configured using the following arguments:

type=value

Specifies the type of indexing. Valid values are ‘index’, for direct indexed structure, ‘rev-index’ for reverse indexing, and ‘hash’ for hashed structure.

param=number

Specifies indexing level.

user=string

Specifies indexing key. The only meaningful value, as of Mailutils version 3.5 is ‘user=${user}’.

Let’s assume the traditional mail layout, in which incoming mails are stored in a UNIX mailbox named after the recipient user name and located in /var/mail directory. The mailbox-pattern for this case is:

  mailbox-pattern "/var/mail/${user}";

It is entirely equivalent to specifying ‘mail-spool "/var/mail"’.

Now, if the layout is the same, but mailboxes are kept in ‘maildir’ format, then the corresponding statement is:

  mailbox-pattern "maildir:///var/mail/${user}";

Finally, if the mailboxes are stored in a directly-indexed directory with two levels of indexing, the URL is:

  mailbox-pattern "maildir:///var/mail;type=index;param=2;user=${user}";

If neither mailbox-pattern nor mail-spool are given, the mailbox names are determined using the following algorithm:

  1. If environment variable FOLDER is set, use its value.
  2. Otherwise, if environment variable MAIL is set, use its value.
  3. If neither of these is set, construct the mailbox name by concatenating the built-in mail spool directory name, a directory separator, and the user name.

    The built-in mail spool directory name is determined at compile time, using the ‘_PATH_MAILDIR’ define from the include file paths.h. If this value is not defined, /var/mail or /usr/spool/mail is used.

Configuration: mailbox-type type

Specifies the type of mailboxes. By default, ‘mbox’ (UNIX mailbox) is assumed. This can be changed while configuring the package by setting MU_DEFAULT_SCHEME configuration variable. The default value can be verified by running mailutils info scheme.

Configuration: folder dir

Sets user mail folder directory. Its value is used when expanding ‘plus-notation’, i.e. such mailbox names as +inbox. The ‘+’ sign is replaced by dir, followed by a directory separator (‘/’).

The dir argument can contain mailbox type prefix, e.g ‘mh://Mail’.

The default folder name is ‘Mail/’.

3.2.8 The locking Statement

Syntax

locking {
  # Default locker flags.
  flags arg;
  
  # Set timeout for acquiring the lock.
  retry-timeout arg;
  
  # Set the maximum number of times to retry acquiring the lock.
  retry-count number;
  
  # Expire locks older than this amount of time.
  expire-timeout number;
  
  # Use prog as external locker program.
  external-locker prog;
}

Description

This block statement configures various parameters used when locking UNIX mailboxes in order to prevent simultaneous writes.

It is important to note, that locking applies only to traditional UNIX mailboxes (see mbox). All other mailbox types don’t require locking.

Configuration: flags string

Set locking flags. Argument is a string consisting of one or more of the following letters:

E

Use an external program to manage locks. The program is given by the external-locker statement (see below).

R

If the locking attempt failed, retry it. This is the default. The number of retries, and time interval between the two successive attempts is given by retry-count and retry-timeout statements, correspondingly.

T

If a lock file exists, check its modification time and, if it is older than a predefined amount of time, remove the lock. The amount of time is specified by expire-timeout statement.

P

Store the PID of the locking process in a lock file.

Configuration: retry-count number

Number of locking attempts. The ‘P’ flag must be set for this to take effect.

Configuration: retry-timeout seconds

Time interval, in seconds, between the two successive locking attempts. The ‘P’ flag must be set for this to take effect.

Configuration: expire-timeout seconds

Remove existing lock file, if it is created more than this number of seconds ago. The ‘T’ flag must be set for this to take effect.

Configuration: external-locker string

Determines the external locker program to use. The string argument is the valid command line, starting with the full program name. The ‘E’ flag must be set for this to take effect.

3.2.9 The mailer Statement

Syntax

mailer {
  url url;
}

Description

A mailer is a special logical entity GNU Mailutils uses for sending messages. Its internal representation is discussed in Mailer. The mailer statement configures it.

The mailer statement contains a single sub-statement:

Configuration: url str

Set the mailer URL.

GNU Mailutils supports three types of mailer URLs, described in the table below:

smtp://[user[:pass][;auth=mech,...]@]host[:port][;params]
smtps://[user[:pass][;auth=mech,...]@]host[:port][;params]

Send messages using SMTP protocol. See SMTP Mailboxes, for a detailed description of the URL and its parts.

sendmail[://progname]

Use sendmail-compatible program progname. Sendmail-compatible means that the program must support following command line options:

-oi

Do not treat ‘.’ as message terminator.

-f addr

Use addr as the sender address.

-t

Get recipient addresses from the message.

See sendmail, for details.

prog://progname?query

A prog mailer. This is a generalization of ‘sendmail’ mailer that allows to use arbitrary external programs as mailers.

It is described in detain in prog.

3.2.10 The acl Statement

Syntax

acl {
  # Allow connections from this IP address.
  allow [from] ip;
  
  # Deny connections from this IP address.
  deny [from] ip;
  
  # Log connections from this IP address.
  log [from] ip [string];
  
  /* Execute supplied program if a connection from this
     IP address is requested. */
  exec [from] ip program;
  
  /* Use program to decide whether to allow connection
     from ip. */
  ifexec [from] ip program;
}

Description

The ACL statement defines an Access Control List, a special structure that controls who can access the given Mailutils resource.

The acl block contains a list of access controls. Each control can be regarded as a function that returns a tree-state value: ‘True’, ‘False’ and ‘Don't know’. When a remote party connects to the server, each of controls is tried in turn. If a control returns ‘False’, access is denied. If it returns ‘True’, access is allowed. If it returns ‘Don't know’, then the next control is tried. It is unclear whether to allow access if the last control in list returned ‘Don't know’. GNU Mailutils 3.5 issues a warning message and allows access. This default may change in future versions. Users are advised to write their ACLs so that the last control returns a definite answer (either True or False).

In the discussion below, wherever cidr appears as an argument, it can be replaced by any of:

The following controls are understood:

Configuration: allow [from] cidr

Allow connections from IP addresses matching this cidr block.

Configuration: deny [from] cidr

Deny connections from IP addresses matching this cidr block.

Configuration: ifexec [from] cidr program

When a connection from the cidr block is requested, execute the program program. If its exit code is ‘0’, then allow connection. Otherwise, deny it.

The program argument undergoes variable expansion and word splitting. The following variables are defined:

aclno

Ordinal number of the control in the ACL. Numbers begin from ‘1’.

family

Connection family. Mailutils version 3.5 supports the following families: ‘AF_INET’, ‘AF_INET6’ and ‘AF_UNIX’.

address

Remote IP address (for ‘AF_INET’ and ‘AF_INET6’) or socket name (for ‘AF_UNIX’). Notice that most Unixes return empty string instead of the ‘AF_UNIX’ socket name, so do not rely on it.

port

Remote port number (for ‘AF_INET’ and ‘AF_INET6’).

Configuration: exec [from] cidr program

If a connection from the cidr block is requested, execute the given program. Do not wait for it to terminate, and ignore its exit code. The program is subject for variable expansion as in ‘ifexec’.

The following two controls are provided for logging purposes and as a means of extensions. They always return a ‘Don't know’ answer, and therefore should not be used at the end of an ACL:

Configuration: log [from] cidr [string]

Log connections from addresses in this cidr. The MU_DIAG_INFO channel is used. If the logging goes to syslog, it is translated to the LOG_INFO priority.

If string is not given, the format of the log entry depends on the connection family, as described in the table below:

{AF_INET ip:port}

For inet IPv4 connections. The variables ip and port are replaced by the remote IP address and port number, correspondingly.

{AF_UNIX}

For connections over UNIX sockets. The socket name, if available, may be printed before the closing curly brace.

If string is supplied, it undergoes variable expansions as described for the ‘ifexec’.

For example, the following ACL makes a Mailutils server log every incoming connection:

  acl {
     log from any "Connect from ${address}";
     ...
  }

This was the default behavior for the versions of Mailutils up to ‘1.2’, so if you got used to its logs you might wish to add the above in your configuration files.

Configuration: exec [from] cidr program

If a connection from the cidr block is requested, execute the given program. Do not wait for it to terminate, and ignore its exit code.

3.2.11 The tcp-wrappers Statement

Syntax

tcp-wrappers {
  # Enable TCP wrapper access control.
  enable bool;
  
  # Set daemon name for TCP wrapper lookups.
  daemon name;
  
  # Use file for positive client address access control.
  allow-table file;
  
  # Use file for negative client address access control.
  deny-table file;
}

Description

The tcp-wrappers statements provides an alternative way to control accesses to the resources served by GNU Mailutils. This statement is enabled if Mailutils is compiled with TCP wrappers library libwrap.

Access control using TCP wrappers is based on two files, called tables, containing access rules. There are two tables: the allow table, usually stored in file /etc/hosts.allow, and the deny table, kept in file /etc/hosts.deny. The rules in each table begin with an identifier called daemon name. A utility that wishes to verify a connection, selects the entries having its daemon name from the allow table. A connection is allowed if it matches any of these entries. Otherwise, the utility retrieves all entries with its daemon name from the deny table. If any of these matches the connection, then it is refused. Otherwise, if neither table contains matching entries, the connection is allowed.

The description of a TCP wrapper table format lies outside the scope of this document. Please, see ACCESS CONTROL FILES in hosts_access(5) man page, for details.

Configuration: enable bool

Enable access control using TCP wrappers. It is on by default.

Configuration: daemon name

Set daemon name for TCP wrapper lookups. By default, the name of the utility is used. E.g. imap4d uses ‘imap4d’ as the daemon name.

Configuration: allow-table file

Use file as allow table. By default, /etc/hosts.allow is used.

Configuration: deny-table file

Use file as negative table. By default, /etc/hosts.deny is used.

3.2.12 Server Settings

GNU Mailutils offers several server applications: pop3d, imap4d, comsatd, to name a few. Being quite different in their purpose, they are very similar in some aspects of their architecture. First of all, they all support two operating modes: daemon, where a program disconnects from the controlling terminal and works in background, and inetd, where it remains in foreground and communicates with the remote party via standard input and output streams. Secondly, when operating as daemons, they listen to a preconfigured set of IP addresses and ports, reacting to requests that arrive.

To configure these aspects of functionality, GNU Mailutils provides Server Configuration Settings, which is describes in this subsection.

3.2.12.1 General Server Configuration


Syntax:

# Set daemon mode.
mode ‘inetd|daemon’;

# Run in foreground.
foreground bool;

# Maximum number of children processes to run simultaneously.
max-children number;

# Store PID of the master process in file.
pidfile file;

# Default port number.
port portspec;

# Set idle timeout.
timeout time;

Description: These statements configure general server-related issues.

Configuration: mode string;

Set operation mode of the server. Two operation modes are supported:

daemon

Run as a standalone daemon, disconnecting from the controlling terminal and continuing to run in the background. In this case, it is the server that controls what IP addresses and ports to listen on, who is allowed to connect and from where, how many clients are allowed to connect simultaneously, etc. Most remaining configuration statements are valid only in the daemon mode.

This is the preferred mode of operation for GNU Mailutils servers.

inetd

Operate as a subprocess of UNIX internet super-server program, inetd. See Internet super-server in inetd(8) man page, for a detailed description of the operation of inetd and its configuration. In this case it is inetd that controls all major connectivity aspects. The Mailutils server program communicates with it via standard input and output streams.

For historical reasons, this mode is the default, if no mode statement is specified. This will change in the future.

Configuration: foreground bool;

[daemon mode only]
Do not disconnect from the controlling terminal and remain in the foreground.

Configuration: max-children number;

[daemon mode only]
Set maximum number of child processes allowed to run simultaneously. This equals the number of clients that can use the server simultaneously.

The default is 20 clients.

Configuration: pidfile file;

After startup, store the PID of the main server process in file. When the process terminates, the file is removed. As of version 3.5, GNU Mailutils servers make no further use of this file. It is intended for use by automated startup scripts and controlling programs (e.g. see GNU pies in GNU Pies Manual).

Configuration: port portspec;

[daemon mode only]
Set default port to listen to. The portspec argument is either a port number in decimal, or a symbolic service name, as listed in /etc/services (see Internet network services list in services(5) man page).

Configuration: timeout time;

Sets maximum idle time out in seconds. If a client does not send any requests during time seconds, the child process terminates.

3.2.12.2 The server Statement


Syntax:

server ipaddr[:port] {
  # Run this server as a single process.
  single-process bool;
  
  # Log the session transcript.
  transcript bool;

  # Set idle timeout.
  timeout time;

  # Size of the queue of pending connections
  backlog <number: callback>;

  # Kind of TLS encryption to use for this server.
  tls-mode ‘no’|‘ondemand’|‘required’|‘connection’;

  tls {
    # Specify SSL certificate file.
    ssl-certificate-file string;
    # Specify SSL certificate key file.
    ssl-key-file file;
    # Specify trusted CAs file.
    ssl-ca-file file;
    # Set the priorities to use on the ciphers, methods, etc.
    ssl-priorities string;
  }
  
  # Set server specific ACLs.
  acl { /* See ACL Statement. */ };
}

Description:

The server block statement configures a single TCP or UDP server. It takes effect only in daemon mode (see server mode). The argument to this statement specifies the IP address, and, optionally, the port, to listen on for requests. The ipaddr part is either an IPv4 address in dotted-quad form, or a IPv6 address enclosed in square brackets, or a symbolic host name which can be resolved to such an address. Specifying ‘0.0.0.0’ as the ipaddr means listen on all available network interfaces. The port argument is either a port number in decimal, or a symbolic service name, as listed in /etc/services (see Internet network services list in services(5) man page). If port is omitted, Mailutils uses the port set by port statement (see port), or, in its absence, the default port number, which depends on a server being used (e.g. 110, for pop3d, 143, for imap4d, etc.).

Any number of server statements may be specified in a single configuration file, allowing to set up the same service on several IP addresses and/or port numbers, and with different configurations.

Statements within the server block statement configure this particular server.

Configuration: single-process bool;

If set to true, this server will operate in single-process mode. This mode is intended for debugging only, do not use it on production servers.

Configuration: transcript bool;

Enable transcript of the client-server interaction. This may generate excessive amounts of logging, which in turn may slow down the operation considerably.

Session transcripts are useful in fine-tuning your configurations and in debugging. They should be turned off on most production servers.

Configuration: timeout time;

Set idle timeout for this server. This overrides the global timeout settings (see timeout).

Configuration: backlog number;

Configures the size of the queue of pending connections

Configuration: tls-mode mode;

Configure the use of TLS encryption. The mode argument is one of the following:

no

TLS is not used. The corresponding command (STLS, for POP3, STARTTLS, for IMAP4) won’t be available even if the TLS configuration is otherwise complete.

ondemand

TLS is initiated when the user issues the appropriate command. This is the default when TLS is configured.

required

Same as above, but the use of TLS is mandatory. The authentication state is entered only after TLS negotiation has succeeded.

connection

TLS is always forced when the connection is established. For pop3d this means using POP3S protocol (or IMAP4S, for imap4d).

Configuration: tls { ... }

The tls statement configures SSL certificate and key files, as well as other SSL settings for use in this server. It is used when tls-mode is set to any of the following values: ondemand, required, connection.

If tls-mode is set to any of the values above and tls section is absent, settings from the global tls section will be used. In this case, it is an error if the global tls section is not defined.

See tls statement, for a discussion of its syntax.

Configuration: acl

This statement defines a per-server Access Control List. Its syntax is as described in ACL Statement. Per-server ACLs complement, but not override, global ACLs, i.e. if both global ACL and per-server ACL are used, the connection is allowed only if both of them allow it, and is denied if any one of them denies it.

3.2.13 The auth Statement

Syntax

auth {
  # Set a list of modules for authentication.
  authentication module-list;
  
  # Set a list of modules for authorization.
  authorization module-list;
}

Description

Some mail utilities provide access to their services only after verifying that the user is actually the person he is claiming to be. Such programs are, for example, pop3d and imap4d. The process of the verification is broken down into two stages: authorization and authentication. In authorization stage the program retrieves the information about a particular user. In authentication stage, this information is compared against the user-supplied credentials. Only if both stages succeed is the user allowed to use the service.

A set of modules is involved in performing each stage. For example, the authorization stage can retrieve the user description from various sources: system database, SQL database, virtual domain table, etc. Each module is responsible for retrieving the description from a particular source of information. The modules are arranged in a module list. The modules from the list are invoked in turn, until one of them succeeds or the list is exhausted. In the latter case the authorization fails. Otherwise, the data returned by the succeeded module are used in authentication.

Similarly, authentication may be performed in several ways. The authentication modules are also grouped in a list. Each module is tried in turn until either a module succeeds, in which case the authentication succeeds, or the end of the list is reached.

For example, the authorization list

  (system, sql, virtdomains)

means that first the system user database (/etc/password) is searched for a description of a user in question. If the search fails, the SQL database is searched. Finally, if it also fails, the search is performed in the virtual domain database.

Note, that some authentication and/or authorization modules may be disabled when configuring the package before compilation. The names of the disabled modules are nevertheless available for use in runtime configuration options, but they represent a “fail-only” functionality, e.g. if the package was compiled without SQL support then the module ‘sql’ in the above example will always fail, thus passing the execution on to the next module.

The auth statement configures authentication and authorization.

Configuration: authorization module-list

Define a sequence of modules to use for authorization. Modules will be tried in the same order as listed in module-list.

The modules available for use in authorization list are:

system

User credentials are retrieved from the system user database (/etc/password).

sql

User credentials are retrieved from a SQL database. A separate configuration statement, sql, is used to configure it (see sql statement).

virtdomain

User credentials are retrieved from a “virtual domain” user database. Virtual domains are configured using virtdomain statement (see virtdomain statement).

radius

User credentials are retrieved using RADIUS. See radius statement, for a detailed description on how to configure it.

ldap

User credentials are retrieved from an LDAP database. See ldap statement, for an information on how to configure it.

Unless overridden by authorization statement, the default list of authorization modules is:

  1. generic
  2. system
  3. pam
  4. sql
  5. virtual
  6. radius
  7. ldap
Configuration: authentication module-list

Define a sequence of modules to use for authentication. Modules will be tried in the same order as listed in module-list.

The following table lists modules available for use in module-list:

generic

The generic authentication type. User password is hashed and compared against the hash value returned in authorization stage.

system

The hashed value of the user password is retrieved from /etc/shadow file on systems that support it.

sql

The hashed value of the user password is retrieved from a SQL database using query supplied by getpass statement (see getpass).

pam

The user is authenticated via pluggable authentication module (PAM). The PAM service name to be used is configured in pam statement (see pam statement).

radius

The user is authenticated on a remote RADIUS server. See radius statement.

ldap

The user is authenticated using LDAP. See ldap statement.

Unless overridden by authentication statement, the list of authentication modules is the same as for authorization, i.e.:

  1. generic
  2. system
  3. pam
  4. sql
  5. virtual
  6. radius
  7. ldap

3.2.14 PAM Statement

Syntax

pam {
  # Set PAM service name.
  service text;
}

Description

The pam statement configures PAM authentication. It contains a single sub-statement:

Configuration: service text

Define service name to look for in PAM configuration. By default, the base name of the Mailutils binary is used.

This statement takes effect only if ‘pam’ is listed in authentication statement (see auth statement).

3.2.15 The virtdomain Statement

Syntax

virtdomain {
  # Name of the virtdomain password directory.
  passwd-dir dir;
}

Description

Virtual mail domains make it possible to handle several mail domains each having a separate set of users, on a single server. The domains are completely independent of each other, i.e. the same user name can be present in several domains and represent different users.

When authenticating to a server with virtual domain support enabled, users must supply their user names with domain parts. The server strips off the domain part and uses it as a name of UNIX-format password database file, located in the domain password directory. The latter is set using passwd-dir statement.

Configuration: passwd-dir dir

Set virtual domain password directory.

For example, when authenticating user ‘smith@example.com’, the server will use password file named dir/example.com. This file must be in UNIX passwd format (see password file in passwd(5) man page), with encrypted passwords stored in it (as of GNU Mailutils version 3.5, there is no support for shadow files in virtual password directories, although this is planned for future versions). Here is an example record from this file:

smith:Wbld/G2Q2Le2w:1000:1000:Email Account:/var/mail/domain/smith:/dev/null

Notice, that it must contain user names without domain parts.

The pw_dir field (the 6th field) is used to determine the location of the maildrop for this user. It is defined as pw_dir/INBOX. In our example, the maildrop for user ‘smith’ will be located in file /var/mail/domain/smith.

If user did not supply his domain name, or if no matching record was found in the password file, or if the file matching the domain name does not exist, then GNU Mailutils falls back to alternative method. First, it tries to determine the IP address of the remote party. Then the domain name corresponding to that address is looked up in the DNS system. Finally, this domain name is used as a name of the password file.

3.2.16 The radius Statement

Syntax

radius {
  # Set radius configuration directory.
  directory dir;
  # Radius request for authorization.
  auth request;
  # Radius request for getpwnam.
  getpwnam request;
  # Radius request for getpwuid.
  getpwuid request;
}

Description

The radius block statement configures RADIUS authentication and authorization.

Mailutils uses GNU Radius library, which is configured via raddb/client.conf file (see Client Configuration in GNU Radius Reference Manual). Its exact location depends on configuration settings that were used while compiling GNU Radius. Usually it is /usr/local/etc, or /etc. This default can also be changed at run time using directory statement:

Configuration: directory dir

Set full path name to the GNU Radius configuration directory.

It authorization is used, the Radius dictionary file must declare the the following attributes:

AttributeTypeDescription
GNU-MU-User-NamestringUser login name
GNU-MU-UIDintegerUID
GNU-MU-GIDintegerGID
GNU-MU-GECOSstringGECOS
GNU-MU-DirstringHome directory
GNU-MU-ShellstringUser shell
GNU-MU-MailboxstringUser mailbox
GNU-MU-QuotaintegerMail quota (in bytes)

A dictionary file with appropriate definitions is included in the Mailutils distribution: examples/config/mailutils.dict. This file is not installed by default, you will have to manually copy it to the GNU Radius raddb/dict directory and include it in the main dictionary file raddb/dictionary by adding the following statement:

$INCLUDE dict/mailutils.dict

Requests to use for authentication and authorization are configured using three statements: auth, getpwnam and getpwuid. Each statement takes a single argument: a string, containing a comma-separated list of assignments. An assignment specifies a particular attribute-value pair (see RADIUS Attributes in GNU Radius Reference Manual) to send to the server. The left-hand side of the assignment is a symbolic attribute name, as defined in one of Radius dictionaries (see Dictionary of Attributes in GNU Radius Reference Manual). The value is specified by the right-hand side of assignment. For example:

"Service-Type = Authenticate-Only, NAS-Identifier = \"mail\""

The assignment may contain references to the following variables (see Variables):

user

The actual user name (for auth and getpwnam), or user ID (for getpwuid). For example:

User-Name = ${user}
passwd

User password. For examples:

User-Password = ${passwd}
Configuration: auth pairlist

Specifies the request to be sent to authenticate the user. For example:

auth "User-Name = ${user}, User-Password = ${passwd}";

The user is authenticated only if this request returns Access-Accept (see Access-Accept in GNU Radius Reference Manual). Any returned attribute-value pairs are ignored.

Configuration: getpwnam pairlist

Specifies the request that returns user information for the given user name. For example:

getpwnam "User-Name = ${user}, State = getpwnam, "
         "Service-Type = Authenticate-Only";

If the requested user account exists, the Radius server must return Access-Accept packet with the following attributes: GNU-MU-User-Name, GNU-MU-UID, GNU-MU-GID, GNU-MU-GECOS, GNU-MU-Dir, GNU-MU-Shell.

The attributes GNU-MU-Mailbox and GNU-MU-Quota are optional.

If GNU-MU-Mailbox is present, it must contain a valid mailbox URL (see URL). If GNU-MU-Mailbox is not present, Mailutils constructs the mailbox name using the settings from the mailbox configuration statement (see Mailbox Statement), or built-in defaults, if it is not present.

If GNU-MU-Quota is present, it specifies the maximum mailbox size for this user, in bytes. In the absence of this attribute, mailbox size is unlimited.

Configuration: getpwuid pairlist

Specifies the request that returns user information for the given user ID. In pairlist, the ‘user’ macro-variable is expanded to the numeric value of ID. For example:

getpwuid "User-Name = ${user}, State = getpwuid, "
         "Service-Type = Authenticate-Only";

The reply to getpwuid request is the same as to getpwnam request (see above).

3.2.17 The sql Statement

Syntax

sql {
  # Set SQL interface to use.
  interface ‘mysql|odbc|postgres’;
  # SQL server host name.
  host arg;
  # SQL user name.
  user arg;
  # Password for the SQL user.
  passwd arg;
  # SQL server port.
  port arg;
  # Database name.
  db arg;
  # Type of password returned by getpass query.
  password-type ‘plain | hash | scrambled’;
  # Set a field-map for parsing SQL replies.
  field-map list;
  # SQL query returning the user’s password.
  getpass query;
  # SQL query to use for getpwnam requests.
  getpwnam query;
  # SQL query to use for getpwuid requests.
  getpwuid query;
}

Description

The sql statement configures access credentials to SQL database and the queries for authentication and authorization.

GNU Mailutils supports three types of SQL interfaces: MySQL, PostgreSQL and ODBC. The latter is a standard API for using database management systems, which can be used to communicate with a wide variety of DBMS.

Configuration: interface type

Configures type of DBMS interface. Allowed values for type are:

mysql

Interface with a MySQL server (http://www.mysql.org).

odbc

Use ODBC interface. See http://www.unixodbc.org, for a detailed description of ODBC configuration.

postgres

Interface with a PostgreSQL server (http://www.postgres.org).

The database and database access credentials are configured using the following statements:

Configuration: host arg

The host running the SQL server. The value can be either a host name or an IP address in dotted-quad notation, in which case an INET connection is used, or a full pathname to a file, in which case a connection to UNIX socket is used.

Configuration: port arg

TCP port the server is listening on (for INET connections). This parameter is optional. Its default value depends on the type of database being used.

Configuration: db arg;

Name of the database.

Configuration: user arg

SQL user name.

Configuration: passwd arg;

Password to access the database.

Configuration: password-encryption arg;

Defines type of encryption used by the password returned by getpass query (see below). Possible arguments are:

plain

Password is in plain text.

crypt
hash

Password is encrypted by system crypt function (see crypt in crypt(3) man page).

scrambled

Password is encrypted by MySQL password function.

Configuration: getpwnam query

Defines SQL query that returns information about the given user. The query is subject to variable expansion (see Variables). The only variable defined is ‘$user’, which expands to the user name.

The query should return a single row with the following columns:

name

User name.

passwd

User password.

uid

UID of the user.

gid

GID of the primary group.

gecos

Textual description of the user.

dir

User’s home directory

shell

User’s shell program.

The following columns are optional:

mailbox

Full pathname of the user’s mailbox. If not returned or NULL, the mailbox is determined using the default algorithm (see Mailbox).

quota

Upper limit on the size of the mailbox. The value is either an integer number optionally followed by one of the usual size suffixes: ‘K’, ‘M’, ‘G’, or ‘T’ (case-insensitive).

Configuration: getpwuid query

Defines SQL query that returns information about the given UID. The query is subject to variable expansion (see Variables). The only variable defined is ‘$user’, which expands to the UID.

The query should return a single row, as described for getpwnam.

Configuration: getpass query

Defines SQL query that returns the password of the given user. The query is subject to variable expansion (see Variables). The only variable defined is ‘$user’, which expands to the user name.

The query should return a row with a single column, which gives the password. The password can be encrypted as specified by the password-encryption statement.

Configuration: field-map list

Defines a translation map for column names. The list is a list of mappings. Each mapping is a string ‘name=column’, where name is one of the names described in getpw column names, and column is the name of the column in the returned row that should be used instead. The effect of this statement is similar to that of SQL AS keyword. E.g. the statement

field-map (uid=user_id);

has the same effect as using ‘SELECT user_id AS uid’ in the SQL statement.

3.2.18 The ldap Statement

Syntax

ldap {
  # Enable LDAP lookups.
  enable bool;
  # Set URL of the LDAP server.
  url url;
  # Base DN for LDAP lookups.
  base string;
  # DN for accessing LDAP database.
  binddn string;
  # Password for use with binddn.
  passwd string;
  # Use TLS encryption.
  tls bool;
  # Set LDAP debugging level.
  debug number;
  # Set a field-map for parsing LDAP replies.
  field-map list;
  # LDAP filter to use for getpwnam requests.
  getpwnam string;
  # LDAP filter to use for getpwuid requests.
  getpwuid filter;
}

Description

The ldap statement configures the use of LDAP for authentication.

Configuration: enable bool

Enables LDAP lookups. If absent, ‘enable On’ is assumed.

Configuration: url url

Sets the URL of the LDAP server.

Configuration: base string

Defines base DN for LDAP lookups.

Configuration: binddn string

Defines the DN for accessing LDAP database.

Configuration: passwd string

Password for use when binding to the database.

Configuration: tls bool

Enable the use of TLS when connecting to the server.

Configuration: debug number

Set LDAP debug level. Please refer to the OpenLDAP documentation, for allowed number values and their meaning.

Configuration: field-map map

Defines a map for parsing LDAP replies. The map is a list of mappings1. Each mapping is ‘field=attr’, where attr is the name of the LDAP attribute and field is a field name that declares what information that attribute carries. Available values for field are:

name

User name.

passwd

User password.

uid

UID of the user.

gid

GID of the primary group.

gecos

Textual description of the user.

dir

User’s home directory

shell

User’s shell program.

The default mapping is

  ("name=uid",
   "passwd=userPassword",
   "uid=uidNumber",
   "gid=gidNumber",
   "gecos=gecos",
   "dir=homeDirectory",
   "shell=loginShell")
Configuration: getpwnam string

Defines the LDAP filter to use for ‘getpwnam’ requests. The default is:

  (&(objectClass=posixAccount) (uid=$user))
Configuration: getpwuid string

Defines the LDAP filter to use for ‘getpwuid’ requests. The default filter is:

  (&(objectClass=posixAccount) (uidNumber=$user))

3.2.19 The tls Statement

Syntax

tls {
  # Specify SSL certificate file.
  ssl-certificate-file string;
  # Specify SSL certificate key file.
  ssl-key-file file;
  # Specify trusted CAs file.
  ssl-ca-file file;
  # Set the priorities to use on the ciphers, methods, etc.
  ssl-priorities string;
}

Description

The ‘tls’ statement configures TLS parameters to be used by servers. It can appear both in the global scope and in server scope. Global tls settings are applied for servers that are declared as supporting TLS encryption, but lack the ‘tls’ substatement.

Configuration: ssl-certificate-file string

Specify SSL certificate file.

Configuration: ssl-key-file file

Specify SSL certificate key file.

Configuration: ssl-ca-file file

Specify the trusted certificate authorities file.

Configuration: ssl-priorities string

Set the priorities to use on the ciphers, key exchange methods, MACs and compression methods.

3.2.20 The tls-file-checks Statement

Syntax

tls-file-checks {
  # Configure safety checks for SSL key file.
  key-file list;
  # Configure safety checks for SSL certificate.
  cert-file list;
  # Configure safety checks for SSL CA file.
  ca-file list;
}

Description

This section configures security checks applied to the particular SSL configuration files in order to decide whether it is safe to use them.

Configuration: key-file list

Configure safety checks for SSL key file. Elements of the list are names of individual checks, optionally prefixed with ‘+’ to enable or ‘-’ to disable the corresponding check. Valid check names are:

none

Disable all checks.

all

Enable all checks.

gwrfil

Forbid group writable files.

awrfil

Forbid world writable files.

grdfil

Forbid group readable files.

ardfil

Forbid world writable files.

linkwrdir

Forbid symbolic links in group or world writable directories.

gwrdir

Forbid files in group writable directories.

awrdir

Forbid files in world writable directories,

Configuration: cert-file list

Configure safety checks for SSL certificate. See key-file for a description of list.

Configuration: ca-file list

Configure safety checks for SSL CA file. See key-file for a description of list.

3.2.21 The gsasl Statement

Editor’s note:

This node is to be written.

Syntax

gsasl {
  # Name of GSASL password file.
  cram-passwd file;
  # SASL service name.
  service string;
  # SASL realm name.
  realm string;
  # SASL host name.
  hostname string;
  # Anonymous user name.
  anonymous-user string;
}

3.3 Debugging

Mailutils debugging output is controlled by a set of levels, each of which can be set independently of others. Each debug level consists of a category name, which identifies the part of Mailutils for which additional debugging is desired, and a level number, which tells Mailutils how verbose should its output be.

Valid debug levels are:

error

Displays error conditions which are normally not reported, but passed to the caller layers for handling.

trace0 through trace9

Ten levels of verbosity, ‘trace0’ producing less output, ‘trace9’ producing the maximum amount of output.

prot

Displays network protocol interaction, where applicable.

Implementation and applicability of each level differs between various categories. The full list of categories is available in file libmailutils/diag/debcat in the Mailutils source tree. Most useful categories and levels implemented for them are discussed later in this article.

3.3.1 Level Syntax

Debug levels can be set either from the command line, by using the --debug-level command line option, or from the configuration file, using the ‘.debug.level’ statement. In both cases, the level is specified as a list of individual levels, delimited with semicolons. Each individual level can be specified as:

!category

Disables all levels for the specified category.

category

Enables all levels for the specified category.

category.level

For the given category, enables all levels from ‘error’ to level, inclusive.

category.=level

Enables only the given level for this category.

category.!level

Disables all levels from ‘error’ to level, inclusive, for this category.

category.!=level

Disables only the given level in this category.

category.levelA-levelB

Enables all levels in the range from levelA to levelB, inclusive.

category.!levelA-levelB

Disables all levels in the range from levelA to levelB, inclusive.

Additionally, a comma-separated list of level specifications is allowed after the dot. For example, the following specification:

acl.prot,!=trace9,!trace2

enables in category ‘acl’ all levels, except ‘trace9’, ‘trace0’, ‘trace1’, and ‘trace2’.

3.3.2 BNF

The following specification in Backus-Naur form describes formally the Mailutils debug level:

<debug-spec> ::= <level-spec> | <debug-level-list>
<debug-level-list> ::= <debug-level> |
                       <debug-level-list> ";" <debug-level>
<debug-level> ::= <category> | "!" <category> |
                  <category> "." <level-list>
<level-list> ::= <level-spec> | <level-list> "," <level-spec>
<level-spec> ::=  <level> | <negate-level>
<negate-level> ::= "!" <level>
<level> ::= <level-number> | "=" <level-number> |
            <level-number> "-" <level-number>
<level-number> ::= "error" | "trace0" | "trace1" | "trace2" | "trace3" |
                   "trace4" | "trace5" | "trace6" | "trace7" |
                   "trace8" | "trace9" | "prot"

3.3.3 Debugging Categories

acl

This category enables debugging of Access Control Lists. Available levels are:

error

As usual, displays errors, not directly reported otherwise.

trace0

Basic tracing of ACL processing.

trace9

Traces the process of matching the ACL conditions.

config

This category affects configuration parser and/or lexical analyzer. The following levels are supported:

trace0

Minimal information about configuration statements.

trace2

Trace lexical structure of the configuration files.

trace7

Trace execution of the configuration parser.

Due to its specific nature, this category cannot be enabled from the configuration file. A special hook is provided to facilitate debugging the configuration parser, namely, a pragmatic comment in form:

#debug=debug-level-list

causes debug-level-list to be parsed as described above. Thus, to force debugging of the configuration parser, one would add the following line at the very beginning of the configuration file:

#debug=config.trace7
mailbox

Operations over mailboxes. This module supports the following levels: ‘error’, ‘trace0’, ‘trace1’, and ‘prot’. The latter is used by remote mailbox support libraries.

auth

Enables debugging information about authentication and authorization. This category supports the following levels: ‘error’, ‘trace0’, ‘trace1’, and ‘trace2’.

In level ‘trace0’, user data are reported along with the data source they were obtained from. The output may look like this:

pop3d: source=system, name=gray, passwd=x, uid=120, gid=100,
gecos=Sergey Poznyakoff, dir=/home/gray, shell=/bin/bash,
mailbox=/var/mail/gray, quota=0, change_uid=1

In the ‘trace1’ level, additional flow traces are displayed.

In the level ‘trace2’, a detailed flow trace is displayed, which looks like the following:

pop3d: Trying generic...
pop3d: generic yields 38=Function not implemented
pop3d: Trying system...
pop3d: system yields 0=Success
pop3d: Trying generic...
pop3d: generic yields 4135=Authentication failed
pop3d: Trying system...
pop3d: system yields 0=Success
mailer

Debugs mailer operations. The following levels are supported:

error

Displays mild error conditions.

trace0

Traces mailer operations in general: displays what part of the message is being sent, etc.

trace6

When used together with ‘prot’, displays security-sensitive information (such as passwords, user keys, etc). in plaintext. By default, such information is replaced with asterisks to reduce the possibility of security compromise.

trace7

When used together with ‘prot’, displays the payload information as it is being sent. The payload is the actual message contents, i.e. the part of SMTP transaction that goes after the ‘DATA’ command and which ends with a terminating dot line. Setting this level can generate huge amounts of information.

prot

For SMTP mailer: outputs transcripts of SMTP sessions.

Note: Unless in a very secure environment, it is advised to avoid using level settings such as mailer.prot or mailer (without explicit level part), because the resulting output tends to be extremely copious and reveals sender private and security-sensitive data. If you wish to trace SMTP session flow, use ‘mailer.=prot’ or at least ‘mailer.prot,!trace6’.

serve

This category provides debugging information for Mailutils IP server objects. It supports the ‘error’ and ‘trace0’ levels.

folder

This category controls debugging information shown for operations related to Mailutils folders.

remote

The remote category is used by imap4d and pop3d servers to request showing additional information in the session transcripts. This category takes effect only when the transcript configuration variable is set. Valid levels are:

trace6

Show security-sensitive information (user passwords, etc.)

trace7

Show payload information

3.4 frm and from — List Headers from a Mailbox

Editor’s note:

The information in this node may be obsolete or otherwise inaccurate. This message will disappear, once this node revised.

GNU mailutils provides two commands for listing messages in a mailbox. These are from and frm.

The behavior of both programs is affected by the following configuration file statements:

StatementReference
debugSee debug statement.
tlsSee tls statement.
mailboxSee mailbox statement.
lockingSee locking statement.

frm

The frm utility outputs a header information of the selected messages in a mailbox. By default, frm reads user’s system mailbox and outputs the contents of From and Subject headers for each message. If a folder is specified in the command line, the program reads that folder rather than the default mailbox.

The following command line options alter the behavior of the program:

-d
--debug

Enable debugging output.

-f string
--field string

Display the header named by string instead of From Subject pair.

-l
--to

Include the contents of To header to the output. The output field order is then: To From Subject.

-n
--number

Prefix each line with corresponding message number.

-Q
--Quiet

Be very quiet. Nothing is output except error messages. This is useful in shell scripts where only the return status of the program is important.

-q
--query

Print a message only if there are unread messages in the mailbox.

-S
--summary

Print a summary line.

-s attr
--status attr

Only display headers from messages with the given status. Attr may be one of the following: ‘new’, ‘read’, ‘unread’. It is sufficient to specify only first letter of an attr. Multiple -s options are allowed.

-t
--align

Tidy mode. In this mode frm tries to preserve the alignment of the output fields. It also enables the use of BIDI algorithm for displaying subject lines that contain text in right-to-left orientation (such as Arabic or Hebrew).

from

The from utility displays sender and subject of each message in a mailbox. By default, it reads the user’s system mailbox. If the program is given a single argument, it is interpreted as a name of the user whose mailbox is to be read. Obviously, permissions are required to access that user’s mailbox, so such invocations may be used only by superuser.

The option -f (--file) instructs from to read the given mailbox.

The full list of options, supported by from follows:

-c
--count

Prints only a count of messages in the mailbox and exit.

-d
--debug

Prints additional debugging output.

-s string
--sender=string

Prints only mail with ‘From:’ header containing the supplied string.

-f url
--file=url

Examine mailbox from the given url.

3.5 mail — Send and Receive Mail

Editor’s note:

The information in this node may be obsolete or otherwise inaccurate. This message will disappear, once this node revised.

Mail is an enhanced version of standard /bin/mail program. As well as its predecessor, it can be used either in sending mode or in reading mode. Mail enters sending mode when one or more email addresses were specified in this command line. In this mode the program waits until user finishes composing the message, then attempts to send it to the specified addresses and exits. See Composing Mail, for a detailed description of this behavior.

If the command line contained no email addresses, mail switches to reading mode. In this mode it allows to read and manipulate the contents of the user system mailbox. The --file (-f) command line option allows to specify another mailbox name. For more detail, see Reading Mail.

In addition to the Mailutils configuration file, mail loads the traditional ‘mailrc’-style configuration files. See Mail Configuration Files, for a detailed description of their format.

3.5.1 Invoking mail

General usage of mail program is:

      mail [option...] [address...]

If [address...] part is present, mail switches to mail sending mode, otherwise it operates in mail reading mode.

Mail understands the following command line options:

-A file
--attach=file

Attach file to the composed message. The encoding, content type, and content description are controlled by the --encoding, --content-type, and --content-name options, correspondingly.

The option --attach=- instructs mail to read the file to be attached from the standard input. Interactive shell is disabled in this case.

--attach-fd=fd

Read attachment body from the file descriptor fd. The descriptor must be open for reading. This option is useful when calling mail from another program.

See the options --encoding, --content-type, --content-name, and --content-filename.

-a header:value
--append=header:value

Append the given header to the composed message.

--content-type=type

This options sets the content type to be used by all subsequent --attach options.

--content-filename=name

Set the ‘filename’ parameter in the ‘Content-Disposition’ header for the next --attach-fd option.

--content-name=text

Set the ‘name’ parameter (description) in the ‘Content-Type’ header for the next --attach or --attach-fd option.

-E command
--exec=command

Execute command before opening the mailbox. Any number of --exec options can be given. The commands will be executed after sourcing configuration files (see Mail Configuration Files), but before opening the mailbox.

-e
--exist

Return true if the mailbox contains some messages. Return false otherwise.

This is useful for writing shell scripts.

--encoding=enc

Sets content transfer encoding for use by the subsequent --attach options.

-F
--byname

Record outgoing messages in a file named after the first recipient. The name is the login-name portion of the address found first on the ‘To:’ line in the mail header. This option sets the ‘byname’ variable, which see (see byname).

-f
--file

Operate on the mailbox given by the first non-optional command line argument. If there is no such argument, read messages from the user’s mbox file. See Reading Mail, for more details about using this option.

-H
--headers

Print header summary to stdout and exit.

-i
--ignore

Ignore interrupts when composing the message.

-M
--mime
--no-mime

The --mime option instructs mail to compose MIME messages. It is equivalent for -E 'set mime', except that it is processed after all other options. The --no-mime disables the MIME compose mode, and is a shortcut for -E 'set nomime',

-N
--nosum

Do not display initial header summary.

-n
--norc

Do not read the system-wide mailrc file. See Mail Configuration Files.

-p
--print
--read

Print all mail to standard output. It is equivalent to issuing following commands after starting ‘mail -N’:

print *
quit

except that mail --print does not change status of the messages.

-q
--quit

Cause interrupts to terminate program.

-r address
--return-address=address

Sets the return email address for outgoing mail. See return-address.

--skip-empty-attachments
--no-skip-empty-attachments

Don’t create attachments that would have zero-size body. This option affects all attachments created by --attach and --attach-fd options appearing after it in the command line, as well as the body of the original message.

To cancel its effect, use the --no-skip-empty-attachments option.

-s subj
--subject=subj

Send a message with a Subject of subj. Valid only in sending mode.

-t
--to

Read recipients from the message header. Ignore addresses listed in the command line.

-u user
--user=user

Operate on user’s mailbox. This is equivalent to:

mail -f/spool_path/user

with spool_path being the full path to your mailspool directory
(/var/spool/mail or /var/mail on most systems).

The program also understands the common mailutils options (see Common Options.

3.5.2 How to Specify Message Sets

Many mail commands such as print and delete can be given a message list to operate upon. Wherever the message list is omitted, the command operates on the current message.

The message list in its simplest form is one of:

.

Selects current message. It is equivalent to empty message list.

*

Selects all messages in the mailbox.

^

Selects first non-deleted message.

$

Selects last non-deleted message.

In its complex form, the message list is a comma or whitespace-separated list of message specifiers. A message specifier is one of

Message Number

This specifier addresses the message with the given ordinal number in the mailbox.

Message range

Message range is specified as two message numbers separated by a dash. It selects all messages with the number lying within that range.

Attribute specifier

An Attribute specifier is a colon followed by a single letter. The Attribute specifier addresses all messages in the mailbox that have the given attribute. These are the valid attribute specifiers:

:d

Selects all deleted messages.

:n

Selects all recent messages, i.e. the messages that have not been neither read not seen so far.

:o

Selects all messages that have been seen.

:r

Selects all messages that have been read.

:u

Selects all messages that have not been read.

:t

Selects all tagged messages.

:T

Selects all untagged messages.

Header match

The header match is a string in the form:

[header:]/string/

It selects all messages that contain header field header matching given regexp. If the variable regexp is set, the string is assumed to be a POSIX regexp. Otherwise, a header is considered to match string if the latter constitutes a substring of the former (comparison is case-insensitive).

If header: part is omitted, it is assumed to be ‘Subject:’.

Message body match

The message body match is a string in the form:

:/string/

It selects all messages whose body matches the string. The matching rules are the same as described under “Header match”.

A message specifier can be followed by message part specifier, enclosed in a pair of brackets. A message part specifier controls which part of a message should be operated upon. It is meaningful only for multipart messages. A message part specifier is a comma or whitespace - separated list of part numbers or ranges. Each part number can in turn be message part specifier, thus allowing for operating upon multiply-encoded messages.

The following are the examples of valid message lists:

3.5.3 Composing Mail

You can compose the message by simply typing the contents of it, line by line. But usually this is not enough, you would need to edit your text, to quote some messages, etc. Mail provides these capabilities through compose escapes. The compose escapes are single-character commands, preceded by special escape character, which defaults to ‘~’. The combination escape character + command is recognized as a compose escape only if it occurs at the beginning of a line. If the escape character must appear at the beginning of a line, enter it twice. The actual escape character may be changed by setting the value of escape mail variable (see Mail Variables).

3.5.3.1 Quitting Compose Mode

There are several commands allowing you to quit the compose mode.

Typing the end-of-file character (‘C-D’) on a line alone finishes compose mode and sends the message to its destination. The ‘C-D’ character looses its special meaning if ignoreeof mail variable is set.

If mail variable dot is set, typing dot (‘.’) on a line alone achieves the same effect as ‘C-D’ above.

Finally, using ‘~.’ escape always quits compose mode and sends out the composed message.

To abort composing of a message without sending it, type interrupt character (by default, ‘C-C’) twice. This behavior is disabled when mail variable ignore is set. In this case, you can use ‘~x’ escape to achieve the same effect.

3.5.3.2 Getting Help on Compose Escapes: ~?

The ‘~?’ escape prints on screen a brief summary of the available compose escapes. Please note, that ‘~h’ escape prompts for changing the header values, and does not give help.

3.5.3.3 Editing the Message: ~e and ~v

If you are not satisfied with the message as it is, you can edit it using a text editor specified either by EDITOR or by VISUAL environment variables. The ‘~e’ uses the former, and ‘~v’ uses the latter.

By default both escapes allow you to edit only the body of the message. However, if the editheaders variable is set, mail will load into the editor the complete text of the message with headers included, thus allowing you to change the headers as well.

3.5.3.4 Modifying the Headers: ~h, ~t, ~c, ~b, ~s

To add new addresses to the list of message recipients, use ‘~t’ command, e.g.:

~t name1@domain.net name2

To add addresses to Cc or Bcc, use ‘~c’ or ‘~b’ escapes respectively.

To change the Subject header, use ‘~s’ escape, e.g.:

~s "Re: your message"

Finally, to edit all headers, type ‘~h’ escape. This will present you with the values of To, Cc, Bcc, and Subject headers allowing to edit them with normal text editing commands.

3.5.3.5 Enclosing Another Message: ~m and ~M

If you are sending mail from within mail command mode, you can enclose the contents of any message sent to you by using ‘~m’ or ‘~M’ commands. Typing ‘~m’ alone will enclose the contents of the current message, typing ‘~m 12’ will enclose the contents of message #12 and so on.

The ‘~m’ uses retained and ignored lists when enclosing headers, the ‘~M’ encloses all header fields.

In both cases, the contents of indentprefix mail variable is prepended to each line enclosed.

3.5.3.6 Adding a File to the Message: ~r and ~d

To append the contents of file filename to the message, type

~r filename

or

~< filename

The ‘~d’ escape is a shorthand for

~r dead.letter

3.5.3.7 Attaching a File to the Message

The ‘~+’ escape attaches a file to the message. It takes one to three arguments. The first argument supplies the name of the file to attach:

~+ myfile.txt

The file will be attached with default content-type ‘application/octet-stream’, and encoding ‘base64’ (these can be altered by the --content-type and --encoding command line options, correspondingly).

Optional second argument defines the content type to be used instead of the default one. Optional third argument defines the encoding, e.g.:

~+ myfile.html text/html base64

To list the files attached so far, use the ‘~l’ escape:

~l
multipart/mixed
   1 myfile.html text/html base64

The first line of the output shows the content type of the message. Each subsequent line contains the ordinal number of the attachment, the name of the file, content-type and transfer encoding used.

The ‘~/’ escape toggles the content type bewteen ‘multipart/mixed’, and ‘multipart/alternative’. The new value of the content type is displayed on the screen.

The ‘~^’ escape removes attachments. Its argument is the number of the attachment to remove, e.g.:

~^ 1

3.5.3.8 Printing And Saving the Message

The ‘~p’ escape types the contents of the message entered so far, including headers, on your terminal. You can save the message to an arbitrary file using ‘~w’ escape. It takes the filename as its argument.

3.5.3.9 Signing the Message: ~a and ~A

To save you the effort of typing your signature at the end of each message, you can use ‘~a’ or ‘~A’ escapes. If your signature occupies one line only, save it to the variable sign and use ‘~a’ escape to insert it. Otherwise, if it is longer than one line, save it to a file, store the name of this file in the variable Sign, and use ‘~A’ escape to insert it into the message.

3.5.3.10 Printing Another Message: ~f and ~F

Sometimes it is necessary to view the contents of another message, while composing. These two escapes allow it. Both take the message list as their argument. If they are used without argument, the contents of the current message is printed. The difference between ‘~f’ and ‘~F’ is that the former uses ignored and retained lists to select headers to be displayed, whereas the latter prints all headers.

3.5.3.11 Inserting Value of a Mail Variable: ~i

The ‘~i’ escape enters the value of the named mail variable into the body of the message being composed.

3.5.3.12 Executing Other Mail Commands: ~: and ~-

You can execute a mail command from within compose mode using ‘~:’ or ‘~-’ escapes. For example, typing

~: from :t

will display the from lines of all tagged messages. Note, that executing mail-sending commands from within the compose mode is not allowed. An attempt to execute such a command will result in diagnostic message “Command not allowed in an escape sequence” being displayed. Also, when starting compose mode immediately from the shell (e.g. running ‘mail address@domain’), most mail commands are meaningless, since there is no mailbox to operate upon. In this case, the only commands that can reasonably be used are: alias, unalias, alternate, set, and unset.

3.5.3.13 Executing Shell Commands: ~! and ~|

The ‘~!’ escape executes specified command and returns you to mail compose mode without altering your message. When used without arguments, it starts your login shell. The ‘~|’ escape pipes the message composed so far through the given shell command and replaces the message with the output the command produced. If the command produced no output, mail assumes that something went wrong and retains the old contents of your message.

3.5.4 Composing Multipart Messages

Multipart messages (or MIME, for short) can be used to send text in character set other than ASCII, attach non-text files, send multiple parts in alternative formats, etc.

Technically speaking, the boolean variable mime controls this feature. If it is set (see Setting and Unsetting the Variables), MIME will create MIME messages by default. The variable can be set in the global or user configuration file (see Mail Configuration Files), using the following command:

set mime

It can also be set from the command line, using the --mime option.

GNU mail automatically turns on the MIME mode, when it is requested to send a non-plaintext message, or a message in character set other than ASCII, when the encoding is specified, or when attachments are given.

To send a message in another character set, specify it with the --content-type option:

mail --content-type 'text/plain; charset=utf-8'

The --encoding specifies the encoding to use:

mail --content-type 'text/plain; charset=utf-8' --encoding=base64

Its argument is any encoding supported by GNU mailutils. The two most often used encodings are ‘base64’ and ‘quoted-printable’.

To specify the charset from mail interactive section, enable the “edit headers” mode (set editheaders) and add the needed Content-Type header manually.

GNU mail also gives you a possibility to attach files to the message being sent.

The simplest way to attach a file from command line is by using the --attach (-A) option. Its argument specifies the file to attach. For example, the following will attach the content of the file archive.tar:

$ mail --attach=archive.tar

By default, the content type will be set to ‘application/octet-stream’, and the attachment will be encoded using the ‘base64’ encoding. To change the content type, use the --content-type option. For example, to send an HTML attachment:

$ mail --content-type=text/html --attach=in.html

The --content-type option affects all --attach options that follow it, and the message body (if any). To change the content type, simply add another --content-type option. For example, to send both the HTML file and the archive:

$ mail --content-type=text/html --attach=in.html \
       --content-type=application/x-tar --attach=archive.tar

Similarly, the encoding to use is set up by the --encoding option. As well as --content-type, this option affects all attachments supplied after it in the command line as well as the message body read from the standard input, until changed by the eventual next instance of the same option. Extending the above example:

$ mail --content-type=text/html --encoding=quoted-printable \
       --attach=in.html \
       --content-type=application/x-tar --encoding=base64 \
       --attach=archive.tar

Each attachment can also be assigned a description and a file name. Normally, these are the same as the file name supplied with the --attach option. However, you can change either or both of them using the --content-name and --content-filename, correspondingly. Both of these options affect only the next --attach (or --attach-fd, see below) option.

By default, the message will be assigned the content type ‘multipart/mixed’. To change it to ‘multipart/alternative’, use the --alternative command line option. Using this option also sets the ‘Content-Disposition’ header of each attached message to ‘inline’.

All the examples above will enter the usual interactive shell, allowing you to compose the body of the message. If that’s not needed, the non-interactive use can be forced by redirecting /dev/null to the standard input, e.g.:

$ mail --attach=archive.tar < /dev/null

This will normally produce a message saying:

mail: Null message body; hope that's ok

To suppress this message, unset the ‘nullbodymsg’ variable, as shown in the example below:

$ mail -E 'set nonullbodymsg' --attach=archive.tar < /dev/null

The option --attach=- forces mail to read the file to be attached from the standard input stream. This option disables the interactive mode and sets ‘nonullbodymsg’ implicitly, so that the above example can be rewritten as:

$ mail --attach=- < archive.tar

Special option is provided to facilitate the use of mail in scripts. The --attach-fd=N instructs the program to read the data to be attached from the file descriptor N. The above example is equivalent to:

$ mail --attach-fd=0 < archive.tar

Attachments created with this option have neither filename nor description set, so normally the use of --content-name and/or --content-filename is advised.

The option --skip-empty-attachments instructs mail to skip creating attachments that would have zero-size body. This option affects all attachments created by --attach and --attach-fd options appearing after it in the command line. It also affects the handling of the original message body. To cancel its effect, use the --no-skip-empty-attachments option.

Here are some examples illustrating how it works.

First, consider the following command line

$ mail --attach=archive.tar </dev/null

Assume that archive.tar is not empty.

This will create a MIME message of two parts: the first part having ‘text/html’ type and empty body, and the second part of type ‘application/octet-stream’, with the content copied from the file archive.tar.

Now, if you do:

$ mail --attach=archive.tar --skip-empty-attachments </dev/null

then the created MIME message will contain only one part: that containing archive.tar.

If the file archive.tar has zero length, the resulting archive will still contain the ‘application/octet-stream’ part of zero length. However, if you place the --skip-empty-attachments option before --attach, then the produced message will be empty.

The following Perl program serves as an example of using mail from a script to construct a MIME message on the fly. It scans all mounted file systems for executable files that have setuid or setgid bits set and reports the names of those files in separate attachments. Each attachment is named after the mountpoint it describes.

The script begins with the usual prologue stating the modules that will be used:

#!/usr/bin/perl

use strict;
use autodie;

Then global variables are declared. The ‘@rcpt’ array contains the email addresses of the recipients:

my @rcpt= 'root@example.com';

The ‘@cmd’ variable holds the mail command line. It will be augmented for each file system. The initial value is set as follows:

my @cmd = ('mail',
           '-E set nonullbodymsg',
           '--content-type=text/plain');

The find utility will be used to locate the files. The script will start as many instances as there are mountpoints. Those instances will be run in parallel and their standard output streams will be connected to file descriptors passed to mail invocation in --attach-fd options.

The descriptors will be held in ‘@fds’ array. This will prevent them from being wiped out by the garbage collector. Furthermore, care should be taken to ensure that the O_CLOEXEC flag be not set for these descriptors. This sample script takes a simplistic approach: it instructs Perl not to close first 255 descriptors when executing another programs:

my @fds;
$^F = 255;

The following code obtains the list of mount points:

open(my $in, '-|', 'mount -t nonfs,noproc,nosysfs,notmpfs');
while (<$in>) {
    chomp;
    if (/^\S+ on (?<mpoint>.+) type (?<fstype>.+) /) {

For each mountpoint, the find command line is constructed and launched. The file descriptor is pushed to the ‘@fds’ array to prevent it from being collected by the garbage collector:

	open(my $fd, '-|',
	     "find $+{mpoint} -xdev -type f"
             . " \\( -perm -u+x -o -perm -g+x -o -perm -o+x \\)"
             . " \\( -perm -u+s -o -perm -g+s \\) -print");
	push @fds, $fd;

Now, the mail command is instructed to create next attachment from that file descriptor:

        my $mpname = $+{mpoint};
        $mpname =~ tr{/}{%}; 
        push @cmd,
             "--content-name=Set[ug]id files on $+{mpoint} (type $+{fstype})",
             "--content-filename=$mpname.list",
             '--attach-fd=' . fileno($fd);
    }
}
close $in;

Finally, the emails of the recipients are added to the command line, the standard input is closed to make sure mail won’t enter the interactive mode and the constructed command is executed:

push @cmd, @rcpt;
close STDIN;
system(@cmd);

3.5.5 Reading Mail

To read messages from a given mailbox, use one of the following ways of invoking mail:

mail

To read messages from your system mailbox.

mail -f
mail --file

To read messages from your mailbox ($HOME/mbox). If the --user option (see below) is also given, read messages from that user’s mbox.

mail -f path_to_mailbox
mail --file path_to_mailbox

To read messages from the specified mailbox.

mail -u user
mail --user=user

To read messages from the system mailbox belonging to user.

Please note, that usual mailbox permissions won’t allow you to use the last variant of invocation, unless you are a super-user. Similarly, the last but one variant is also greatly affected by the permissions the target mailbox has.

Notice that path_to_mailbox is not an argument to --file (-f) option, but rather the first non-optional argument on the command line. Therefore, the following three invocations are equivalent:

$ mail -fin mymbox
$ mail -f mymbox -in
$ mail --file -in mymbox
$ mail --file -i mymbox -n

Additionally, for conformance to the GNU standards, the following form is also accepted:

$ mail --file=mymbox -i -n

Unless you have started mail with --norc command line option, it will read the contents of the system-wide configuration file. Then it reads the contents of user configuration file, if any. For detailed description of these files, see Mail Configuration Files. After this initial setup, mail displays the first page of header lines and enters interactive mode. In interactive mode, mail displays its prompt (‘?’, if not set otherwise) and executes the commands the user enters.

3.5.5.1 Quitting the Program

Following commands quit the program:

quit

Terminates the session. If mail was operating upon user’s system mailbox, then all undeleted and unsaved messages that have been read and are not marked with hold flag are saved to the user’s mbox file ($HOME/mbox). The messages, marked with delete are removed. The program exits to the Shell, unless saving the mailbox fails, in which case user can escape with the exit command.

exit
ex
xit

Program exits to the Shell without modifying the mailbox it operates upon.

Typing EOF (‘C-D’) alone is equivalent to ‘quit’.

3.5.5.2 Obtaining Online Help

Following commands can be used during the session to request online help:

help [command]
hel [command]
? [command]

Display detailed command synopsis. If no command is given, help for all available commands is displayed.

list
*

Print a list of available commands.

version
ve

Display program version.

warranty
wa

Display program warranty statement.

3.5.5.3 Moving Within a Mailbox

^

Move to the first undeleted message.

$

Move to the last undeleted message.

next
n

Move to the next message.

previous
prev

Move to the previous message.

3.5.5.4 Changing Mailbox/Directory

cd [dir]
chdir [dir]
ch [dir]

Change to the specified directory. If dir is omitted, $HOME is assumed.

file [mailbox]
fi [mailbox]
folder [mailbox]
fold [mailbox]

Read in the contents of the specified mailbox. The current mailbox is updated as if quit command has been issued. If mailbox is omitted, the command prints the current mailbox name followed by the summary information regarding it, e.g.:

& fold
"/var/spool/mail/gray": 23 messages 22 unread

3.5.5.5 Controlling Header Display

To control which headers in the message should be displayed, mail keeps two lists: a retained header list and an ignored header list. If retained header list is not empty, only the header fields listed in it are displayed when printing the message. Otherwise, if ignored header list is not empty, only the headers not listed in this list are displayed. The uppercase variants of message-displaying commands can be used to print all the headers.

The following commands modify and display the contents of both lists.

discard [header-field-list]
di [header-field-list]
ignore [header-field-list]
ig [header-field-list]

Add header-field-list to the ignored list. When used without arguments, this command prints the contents of ignored list.

retain [header-field-list]
ret [header-field-list]

Add header-field-list to the retained list. When used without arguments, this command prints the contents of retained list.

3.5.5.6 Displaying Information

=

Displays the current message number.

headers [msglist]
h [msglist]

Lists the current pageful of headers.

from [msglist]
f [msglist]

Lists the contents of ‘From’ headers for a given set of messages.

z [arg]

Presents message headers in pagefuls as described for headers command. When arg is ‘.’, it is generally equivalent to headers. When arg is omitted or is ‘+’, the next pageful of headers is displayed. If arg is ‘-’, the previous pageful of headers is displayed. The latter two forms of z command may also take a numerical argument meaning the number of pages to skip before displaying the headers. For example:

& z +2

will skip two pages of messages before displaying the header summary.

size [msglist]
si [msglist]

Lists the message number and message size in bytes for each message in msglist.

folders

Displays the value of folder variable.

summary
su

Displays current mailbox summary. E.g.:

& summary
"/var/spool/mail/gray": 23 messages 22 unread

3.5.5.7 Displaying Messages

print [msglist]
p [msglist]
type [msglist]
t [msglist]

Prints out the messages from msglist. The variable crt determines the minimum number of lines the body of the message must contain in order to be piped through pager command specified by environment variable PAGER. If crt is set to a numeric value, this value is taken as the minimum number of lines. Otherwise, if crt is set without a value then the height of the terminal screen is used to compute the threshold. The number of lines on screen is controlled by screen variable.

Print [msglist]
P [msglist]
Type [msglist]
T [msglist]

Like print but also prints out ignored header fields.

decode [msglist]
dec [msglist]

Print a multipart message. The decode command decodes and prints out specified message parts. E.g.

& decode 15[2]
+---------------------------------------
| Message=15[2]
| Type=message/delivery-status
| encoding=7bit
+---------------------------------------
Content-Type: message/delivery-status
...
top [msglist]
to [msglist]

Prints the top few lines of each message in msglist. The number of lines printed is controlled by the variable toplines and defaults to five.

pipe [msglist] [shell-command]
| [msglist] [shell-command]

Pipe the contents of specified messages through shell-command. If shell-command is empty but the string variable cmd is set, the value of this variable is used as a command name.

struct [msglist]

Prints the MIME structure of each message from msglist. Empty msglist means current message.

Example:

& struct 2
2      multipart/mixed            14k
2[1]   text/plain                 296
2[2]   application/octet-stream    5k
2[3]   text/x-diff                31k

3.5.5.8 Marking Messages

tag [msglist]
ta [msglist]

Tag messages. The tagged messages can be referred to in message list using ‘:t’ notation.

untag [msglist]
unt [msglist]

Clear tags from specified messages. To untag all messages tagged so far type

& untag :t
hold [msglist]
ho [msglist]
preserve [msglist]
pre [msglist]

Marks each message to be held in user’s system mailbox. This command does not override the effect of delete command.

3.5.5.9 Disposing of Messages

delete [msglist]
d [msglist]

Mark messages as deleted. Upon exiting with quit command these messages will be deleted from the mailbox. Until the end of current session the deleted messages can be referred to in message lists using :d notation.

undelete [msglist]
u [msglist]

Clear delete mark from the specified messages.

dp [msglist]
dt [msglist]

Deletes the current message and prints the next message. If msglist is specified, deletes all messages from the list and prints the message, immediately following last deleted one.

3.5.5.10 Saving Messages

save [[msglist] file]
s [[msglist] file]

Takes a message list and a file name or mailbox URL and appends each message in turn to the end of that file or mailbox. Mailbox URLs begin with mailbox type specifier, such as ‘mbox://’, ‘maildir://’, etc. The name of file or mailbox and number of lines and characters appended to it is echoed on the terminal. When writing to file, the numbers represent exact number of lines and characters appended to the file. When file specifies a mailbox, these numbers may differ by the amount of lines/characters needed to represent message envelope for that specific mailbox type.

Each saved message is marked for deletion as if with delete command, unless the variable keepsave is set.

Save [msglist]
S [msglist]

Like save, but the file to append messages to is named after the sender of the first message in msglist. For example:

& from 14 15
 U  14 smith@noldor.org Fri Jun 30 18:11  14/358   The Save c
 U  15 gray@noldor.org  Fri Jun 30 18:30  8/245    Re: The Sa
& Save 14 15
"smith" 22/603

i.e., 22 lines (603 characters) have been appended to the file “smith”. If the file does not exist, it is created.

write [[msglist] file]
w [[msglist] file]

Similar to save, except that only message body (without the header) is saved.

Write [msglist]
W [msglist]

Similar to Save, except that only message body (without the header) is saved.

mbox [msglist]
mb [msglist]
touch [msglist]
tou [msglist]

Mark list of messages to be saved in the user’s mailbox ($HOME/mbox) upon exiting via quit command. This is the default action for all read messages, unless you have variable hold set.

copy [[msglist] file]
c [[msglist] file]

Similar to save, except that saved messages are not marked for deletion.

Copy [msglist]
C [msglist]

Similar to Save, except that saved messages are not marked for deletion.

3.5.5.11 Editing Messages

These command allow to edit messages in a mailbox. Please note, that modified messages currently do not replace original ones. i.e. you have to save them explicitly using your editor’s save command if you do not want the effects of your editing to be lost.

edit [msglist]
e [msglist]

Edits each message in msglist with the editor, specified in EDITOR environment variable.

visual [msglist]
v [msglist]

Edits each message in msglist with the editor, specified in VISUAL environment variable.

3.5.5.12 Aliasing

alias [alias [address...]]
a [alias [address...]]
group [alias [address...]]
g [alias [address...]]

With no arguments, prints out all currently-defined aliases. With one argument, prints out that alias. With more than one argument, creates a new alias or changes an old one.

unalias [alias...]
una [alias...]

Takes a list of names defined by alias commands and discards the remembered groups of users. The alias names no longer have any significance.

alternates name...
alt name...

The alternates command is useful if you have accounts on several machines. It can be used to inform mail that the listed addresses are really you. When you reply to messages, mail will not send a copy of the message to any of the addresses listed on the alternates list. If the alternates command is given with no argument, the current set of alternate names is displayed.

3.5.5.13 Replying

mail [address...]
m [address...]

Switches to compose mode. After composing the message, sends messages to the specified addresses.

reply [msglist]
respond [msglist]
r [msglist]

For each message in msglist, switches to compose mode and sends the composed message to the sender and all recipients of the message.

Reply [msglist]
Respond [msglist]
R [msglist]

Like reply, except that the composed message is sent only to originators of the specified messages.

Notice, that setting mail variable flipr (see Mail Variables) swaps the meanings of the two above commands, so that reply sends the message to the sender and all recipients of the message, whereas Reply sends it to originators only.

followup [msglist]
fo [msglist]

Switches to compose mode. After composing, sends the message to the originators and recipients of all messages in msglist.

Followup [msglist]
F [msglist]

Similar to followup, but reply message is sent only to originators of messages in msglist.

To determine the sender of the message mail uses the list of sender fields (see Controlling Sender Fields). The first field from this list is looked up in message headers. If it is found and contains a valid email address, this address is used as the sender address. If not, the second field is searched and so on. This process continues until a field is found in the headers, or the sender field list is exhausted, whichever happens first.

If the previous step did not determine the sender address, the address from SMTP envelope is used.

Let’s illustrate this. Suppose your mailbox contains the following:

 U  1 block@helsingor.org  Fri Jun 30 18:30  8/245    Re: The Sa
& Print 1
From: Antonius Block <block@helsingor.org>
To: Smeden Plog <plog@helsingor.org>
Date: Tue, 27 Apr 2004 13:23:41 +0300
Reply-To: <root@helsingor.org>
Subject: News

Hi

Now, you issue the following commands:

& sender mail-followup-to reply-to from
& reply
To: <root@helsingor.org>
Subject: Re: News

As you see, the value of Reply-To field was taken as the sender address.

Now, let’s try the following command sequence:

# Clear the sender list
& nosender
# Set new sender list
& sender From

Now, the From address will be taken:

& reply
To: Antonius Block <block@helsingor.org>
Subject: Re: News

3.5.5.14 Controlling Sender Fields

Commands sender and nosender are used to manipulate the contents of the sender field list.

If the command sender is used without arguments, it displays the contents of the sender field list. If arguments are given, each argument is appended to the sender field list. For example:

& sender
Sender address is obtained from the envelope
& sender mail-followup-to reply-to
& sender
mail-followup-to
reply-to
& sender from
& sender
mail-followup-to
reply-to
from

Command nosender is used to remove items from the sender field list:

& sender
mail-followup-to
reply-to
from
& nosender reply-to
& sender
mail-followup-to
from

When used without arguments, this command clears the list:

& nosender
Sender address is obtained from the envelope

3.5.5.15 Incorporating New Mail

The incorporate (inc) command incorporates newly arrived messages to the displayed list of messages. This is done automatically before returning to mail command prompt if the variable autoinc is set.

3.5.5.16 Shell Escapes

To run arbitrary shell command from mail command prompt, use shell (sh) command. If no arguments are specified, the command starts the user login shell. Otherwise, it uses its first argument as a file name to execute and all subsequent arguments are passed as positional parameters to this command. The shell command can also be spelled as !.

3.5.6 Scripting

Comments

The ‘#’ character introduces an end-of-line comment. All characters until and including the end of line are ignored.

Displaying Arbitrary Text

The ‘echo’ (‘ec’) command prints its arguments to stdout.

Sourcing External Command Files

The command ‘source filename’ reads commands from the named file. Its minimal abbreviation is ‘so’.

Setting and Unsetting the Variables

The mail variables are set using ‘set’ (‘se’) command. The command takes a list of assignments. The syntax of an assignment is

name=string

Assign a string value to the variable. If string contains whitespace characters it must be enclosed in a pair of double-quote characters (‘"’)

name=number

Assign a numeric value to the variable.

name

Assign boolean True value.

noname

Assign boolean False value.

Example:

& set askcc nocrt indentprefix="> "

This statement sets askcc to True, crt to False, and indentprefix to “> ”.

To unset mail variables use ‘unset’(‘uns’) command. The command takes a list of variable names to unset.

Example: To undo the effect of the previous example, do:

& unset askcc crt indentprefix

When used without arguments, both set or unset list all currently defined variables. The form of this listing is controlled by variable-pretty-print (varpp) variable. If it is set, a description precedes each variable, e.g.:

# prompt user for subject before composing the message
ask
# prompt user for cc before composing the message
askcc
# output character set for decoded header fields
charset="auto"
# number of columns on terminal screen
columns=80

If variable-pretty-print is not set, only the settings are shown, e.g.:

ask
askcc
charset="auto"
columns=80

A special command is provided to list all internal mail variables:

variable [names...]

If used without arguments, it prints all known internal variables. If arguments are given, it displays only those internal variables that are listed in command line. For each variable, this command prints its name, data type, current value and a short description. For example:

& variable ask datefield
ask, asksub
Type: boolean
Current value: yes
prompt user for subject before composing the message

datefield
Type: boolean
Current value: [not set]
get date from the `Date:' header, instead of the envelope

Setting and Unsetting Shell Environment Variables

Shell environment may be modified using ‘setenv’ (‘sete’) command. The command takes a list of assignments. The syntax of an assignment is:

name=value

If variable name does not already exist in the environment, then it is added to the environment with the value value. If name does exist, then its value in the environment is changed to value.

name

Delete the variable name from the environment (“unset” it).

Conditional Statements

The conditional statement allows to execute a set of mail commands depending on the mode the mail program is in. The conditional statement is:

if cond
...
else
...
endif

where ‘...’ represents the set of commands to be executed in each branch of the statement. cond can be one of the following:

s

True if mail is operating in mail sending mode.

r

True if mail is operating in mail reading mode.

t

True if stdout is a terminal device (as opposed to a regular file).

The conditional statements can be nested to arbitrary depth. The minimal abbreviations for ‘if’, ‘else’ and ‘endif’ commands are ‘i’, ‘el’ and ‘en’.

Example:

if t
set crt prompt="& "
else
unset prompt
endif
if s
alt gray@farlep.net gray@mirddin.farlep.net
set

3.5.7 How to Alter the Behavior of mail

Following variables control the behavior of GNU mail:

append

Type: Boolean, Read-Only
Default: True

Messages saved in mbox are appended to the end rather than prepended. This is the default and cannot be changed. This variable exists only for compatibility with other mailx implementations.

appenddeadletter

Type: Boolean.
Default: False.

If this variable is True, the contents of canceled letter is appended to the user’s dead.letter file. Otherwise it overwrites its contents.

askbcc

Type: Boolean.
Default: False.

When set to True the user will be prompted to enter Bcc field before composing the message.

askcc

Type: Boolean.
Default: True.

When set to True the user will be prompted to enter Cc field before composing the message.

asksub

Type: Boolean.
Default: True in interactive mode, False otherwise.

When set to True the user will be prompted to enter Subject field before composing the message.

autoinc

Type: Boolean.
Default: True.

Automatically incorporate newly arrived messages.

autoprint

Type: Boolean.
Default: False.

Causes the delete command to behave like dp - thus, after deleting a message, the next one will be typed automatically.

bang

Type: Boolean.
Default: False.

When set, every occurrence of ! in arguments to ! command is replaced with the last executed command.

byname

Type: Boolean
Default: Unset

Record outgoing messages in a file named after the first recipient. The name is the login-name portion of the address found first on the ‘To:’ line in the mail header. This variable overrides the ‘record’ variable.

It is set by the --byname (-F) command line option.

datefield

Type: Boolean.
Default: False.

By default the date in a header summary is taken from the SMTP envelope of the message. Setting this variable tells mail to use the date from Date: header field, converted to local time. Notice, that for messages lacking this field mail will fall back to using SMTP envelope.

See fromfield.

charset

Type: string
Default: ‘auto

The value of this variable is the character set used for input and output operations. If the value is ‘auto’, mail will try to deduce the name of the character set from the value of ‘LC_ALL’ environment variable. If the variable contains the character set part (e.g. ‘nb_NO.utf-8’), it will be used. Otherwise, mail will look up in its built-in database the value of the character for this language/territory combination. If ‘LC_ALL’ is not set, the ‘LANG’ environment variable is inspected.

The value of ‘charset’ controls both input and output operations. On input, it is used to set the value of the ‘charset’ parameter in the ‘Content-Type’ MIME header, if its value begins with ‘text/’ and ‘charset’ is not present.

On output, it is used to display values of the header fields encodied using RFC 2047. If the variable is unset, no decoding is performed and the fields are printed as they are. Otherwise, they are recoded to that character set.

cmd

Type: String.
Default: Unset.

Contains default shell command for pipe.

columns

Type: Numeric.
Default: Detected at startup by querying the terminal device. If this fails, the value of environment variable COLUMNS is used.

This variable contains the number of columns on terminal screen.

crt

Type: Boolean or Numeric
Default: True in interactive mode, False otherwise.

The variable crt determines the minimum number of lines the body of the message must contain in order to be piped through pager command specified by environment variable PAGER. If crt is set to a numeric value, this value is taken as the threshold. Otherwise, if crt is set without a value, then the height of the terminal screen is used to compute the threshold. The number of lines on screen is controlled by screen variable.

debug

Type: String to boolean
Default: Not set

Sets mailutils debug level. If set to string, the value must be a valid Mailutils debugging specification. See Debug Statement, for a description.

If unset (i.e. set nodebug), clears and disables all debugging information. If set to ‘true’ (i.e. set debug), sets maximum debugging (‘<trace7’) on mailbox and its underlying objects.

decode-fallback

Type: String.
Default: ‘none’.

This variable controls the way to represent characters that cannot be rendered using current character set. It can have three values:

none

Such characters are not printed at all. The conversion process stops at the first character that cannot be rendered.

copy-pass

The characters are displayed ‘as is’. Notice, that depending on your setup, this may screw-up your terminal settings.

copy-octal

Unprintable characters are represented by their octal codes. Printable ones are printed ‘as is’.

debug

Type: Boolean
Default: Unset

This variable is not used. It exists for compatibility with other mailx implementations and for future use.

dot

Type: Boolean.
Default: False.

If True, causes mail to interpret a period alone on a line as the terminator of a message you are sending.

emptystart

Type: Boolean.
Default: False.

If the mailbox is empty, mail normally prints ‘No mail for user’ and exits immediately. If this option is set, mail will start no matter is the mailbox empty or not.

editheaders

Type: Boolean.
Default: False.

When set, mail will include message headers in the text to be the ~e and ~v escapes, thus allowing you to customize the headers.

escape

Type: String.
Default: ~

If defined, the first character of this option gives the character to denoting escapes.

flipr

Type: Boolean
Default: Unset

If set, the variable flipr swaps the meanings of reply and Reply commands (see Replying).

folder

Type: String.
Default: Unset.

The name of the directory to use for storing folders of messages. If unset, $HOME is assumed.

fromfield

Type: Boolean.
Default: True.

By default the sender address is taken from the ‘From’ header. Unsetting this variable tells mail to obtain it from the SMTP envelope, instead.

See datefield.

header

Type: Boolean.
Default: True, unless started with --nosum (-N) option.

Whether to run headers command automatically after entering interactive mode.

headline

Type: String
Default: ‘%>%a%4m %18f %16d %3l/%-5o %s

Format string to use for the header summary. The ‘%’ character introduces a format specifier. The format specifier consists of optional alignment specifier (‘+’ or ‘-’ sign), optional output width and the specifier letter. Format specifiers are replaced on output with the corresponding piece of information from the message being described.

The ‘-’ character immediately following ‘%’ indicates that this field should be left aligned. The ‘+’ character indicates right alignment. Default alignment depends on the type of the specifier: the specifiers that produce numeric values (‘%l’, ‘%m’, and ‘%o’) are aligned to the right, whereas the ones producing string or date/time values are aligned to the left.

A number following ‘%’ or the alignment flag, indicates the field width.

Consider the ‘%m’ specifier as an example:

%m

Print current message number. Take as much screen columns as necessary for output.

%4m
%+4m

Print current message number. Use exactly 4 screen columns, truncating the output if it does not fit that width. Align the output to the right.

%-4m

Same as above, but align to the left.

Valid format specifiers are:

%a

Message attribute. One of the following letters, or a single horizontal space, if none of them applies:

Mthe message was copied to the mailbox (‘mbox’ command)
Pthe message was preserved (‘hold’ command)
*the message was saved (‘save’ or ‘Save’)
Tthe message was tagged (‘tag’)
Rthe message was read
Nthe message is new (was not seen)
Uthe message was seen, but wasn’t read
%d

The date when the message was received. It is determined from the message header set by the ‘datefield’ variable (see datefield). If that variable is not set, or the requested header is not present in the message, the date from the envelope is used.

The output is formatted according to the following format specification (see Date/time Format String):

%a %b %e %H:%M

I.e.: abbreviated weekday name, abbreviated month name, day of the month as a decimal number, followed by hour and minutes. All names are displayed according to the current locale.

%D{fmt}

Same as ‘%d’, but the date is formatted according to the date/time format fmt. It is essentially a C ‘strftime’ format string, described in detail in Date/time Format String.

For example:

set headline="%4m %20D{%Y-%m-%dT%H:%M:%S}"

Note, that the opening ‘{’ must follow the format letter without any intervening whitespace. If fmt contains ‘{’, ‘}’, or ‘\’, these characters must be escaped with backslash (e.g. ‘\{’).

%Df

A simplified form of the ‘%D’ specifier. It is equivalent to

%D{%f}

where f is a single ‘strftime’ specifier letter. It can be preceded by ‘E’ or ‘O’, if the Single UNIX Specification allows such usage (see conversion specs), e.g. ‘%DOU’.

Notice, that ‘%D’ not followed by a valid time format in either of the above forms is treated as unknown specifier.

%f

The email address of the message sender.

%l

The number of lines of the message.

%m

Message number.

%o

The number of octets (bytes) in the message.

%s

Message subject (if any).

%S

Message subject (if any) in double quotes.

%>

A ‘>’ for the current message, otherwise a space.

%<

A ‘<’ for the current message, otherwise a space.

%%

A ‘%’ character.

hold

Type: Boolean.
Default: False.

When set, all messages marked as read will be retained in the system mailbox.

When not set (the default), such messages will be stored in the user’s secondary mailbox ($HOME/mbox).

ignore

Type: Boolean.
Default: False.

When set to True, mail will ignore keyboard interrupts when composing messages. Otherwise an interrupt will be taken as a signal to abort composing.

ignoreeof

Type: Boolean.
Default: False.

Controls whether typing EOF character terminates the letter being composed.

indentprefix

Type: String.
Default: "\t" (a tab character).

String used by the ~m tilde escape for indenting quoted messages.

inplacealiases

Type: Boolean
Default: False

If set, mail will expand aliases in the address header field before entering send mode (see Composing Mail). By default, the address header fields are left intact while composing, the alias expansion takes place immediately before sending message.

keep

Type: Boolean, Read-Only
Default: True

Truncate the user’s system mailbox when it is empty, instead of removing it. This is the default and cannot be changed. This variable exists only for compatibility with other mailx implementations.

keepsave

Type: Boolean.
Default: False.

Controls whether saved messages should be kept in system mailbox too. This variable is in effect only when operating upon a user’s system mailbox.

mailx

Type: Boolean.
Default: False.

When set, enables mailx compatibility mode. This mode has the following effects:

metamail

Type: Boolean or String.
Default: True.

This variable controls operation of decode command. If it is unset, decode will not attempt any interpretation of the content of message parts. Otherwise, if metamail is set to true, decode will use internal metamail support to interpret message parts. Finally, if metamail is assigned a string, this string is treated as command line of the external metamail command which will be used to display parts of a multipart message. For example:

# Disable MIME interpretation:
set nometamail
# Enable built-in MIME support:
set metamail
# Use external program to display MIME parts:
set metamail="metamail -m mail -p"
mime

Type: String
Default: Unset (false)

If set, this variable instructs mail to compose MIME messages.

It can be set from the command line using --mime option.

mimenoask

Type: String
Default: Empty

By default mail asks for confirmation before running interpreter to view a part of the multi-part message. If this variable is set, its value is treated as a comma-separated list of MIME types for which no confirmation is needed. Elements of this list may include shell-style globbing patterns, e.g. setting

set mimenoask=text/*,image/jpeg

will disable prompting before displaying any textual files, no matter what their subtype is, and before displaying files with type ‘image/jpeg’.

metoo

Type: Boolean.
Default: False.

Usually, when an alias is expanded that contains the sender, the sender is removed from the expansion. Setting this option causes the sender to be included in the group.

mode

Type: String, Read-Only
Default: The name of current operation mode.

This variable keeps the name of the current operation mode. Its possible values are:

headers

The program is started with the --headers (-H) command line option (see Invoking Mail).

exist

The program is started with the --exist (-e) command line option (see Invoking Mail).

print

The program is started with the --print (-p) command line option (see Invoking Mail).

read

The program operates in read mode. This is the default.

send

The program operates in send mode. This means it was given one or more recipient addresses in the command line.

nullbody

Type: Boolean
Default: True

Controls whether mail accepts messages with an empty body. The default value, true, means such messages are sent, and a warning (traditionally saying ‘Null message body; hope that's ok’) is displayed. The text of the warning can be set using nullbodymsg variable (see below).

If nullbody is unset, mail will silently ignore such messages. This can be useful in crontab files, to avoid sending mails when nothing important happens. For example, the crontab entry below will send mail only if the utility some-prog outputs something on its standard output or error:

*/5 * * * * some-prog 2>&1 | \
   /bin/mail -E'set nonullbody' -s 'Periodic synchronization'
showenvelope

Type: Boolean
Default: Unset

If this variable is set, the print command will include the STMP envelope in its output.

nullbodymsg

Type: String
Default: Null message body; hope that’s ok

Keeps the text of the warning, displayed by mail before sending an empty message. When available, the translation of this text, in accordance with the current locale, is displayed.

Unsetting this variable disables the warning.

onehop

Type: Boolean
Default: Unset

This variable is not used. It exists for compatibility with other mailx implementations and for future use.

outfolder

Type: String.
Default: Unset.

Contains the directory in which files created by save, write, etc. commands will be stored. When unset, current directory is assumed.

page

Type: Boolean.
Default: False.

If set to True, the pipe command will emit a linefeed character after printing each message.

prompt

Type: String.
Default: "? "

Contains the command prompt sequence.

quiet

Type: Boolean
Default: Unset

This variable is not used. It exists for compatibility with other mailx implementations and for future use.

quit

Type: Boolean.
Default: False, unless started with --quit (-q) option.

When set, causes keyboard interrupts to terminate the program.

rc

Type: Boolean.
Default: True, unless started with --norc (-N) option.

When this variable is set, mail will read the system-wide configuration file upon startup. See Mail Configuration Files.

readonly

Type: Boolean
Default: False

When set, mailboxes are opened in readonly mode. In this mode, any mail commands that alter the contents of the mailbox are disabled. These commands include, but are not limited to: delete, save and mbox.

record

Type: String.
Default: Unset.

When set, any outgoing message will be saved to the named file.

recursivealiases

Type: Boolean
Default: True

When set, mail will expand aliases recursively.

regex

Type: Boolean.
Default: True.

Setting this to True enables use of regular expressions in ‘/.../’ message specifications.

replyprefix

Type: String
Default: ‘Re:

Sets the prefix that will be used when constructing the subject line of a reply message.

replyregex

Type: String
Default: ‘^re: *

Sets the regular expression used to recognize subjects of reply messages. If the Subject header of the message matches this expression, the value of replyprefix will not be prepended to it before replying. The expression should be a POSIX extended regular expression. The comparison is case-insensitive.

For example, to recognize usual English, Polish, Norwegian and German reply subject styles, use:

set replyregex="^(re|odp|aw|ang)(\\[[0-9]+\\])?:[[:blank:]]"

(Notice the quoting of backslash characters).

return-address

Type: String
Default: unset

Sets the return email address to use when sending messages. If unset, the address is composed from the current user name and the host name.

save

Type: Boolean.
Default: True.

When set, the aborted messages will be stored in the user’s dead.file. See also appenddeadletter.

screen

Type: Numeric.
Default: Detected at startup by querying the terminal device. If this fails, the value of environment variable LINES is used.

This variable contains the number of lines on terminal screen.

sendmail

Type: String.
Default: sendmail:/usr/lib/sendmail

Contains URL of the mail transport agent.

sendwait

Type: Boolean
Default: Unset

This variable is not used. It exists for compatibility with other mailx implementations and for future use.

showto

Type: Boolean
Default: False

If the message was sent by the user, print its recipient address in the header summary.

Sign

Type: String.
Default: Unset.

Contains the filename holding users signature. The contents of this file is appended to the end of a message being composed by ~A escape.

sign

Type: String.
Default: Unset.

Contains the user’s signature. The contents of this variable is appended to the end of a message being composed by ~a escape. Use Sign variable, if your signature occupies more than one line.

showto

Type: Boolean
Default: unset

If this variable is set, mail will show To: addresses instead of From: for all messages that come from the user that invoked the program.

subject

Type: String.
Default: Unset.

Contains default subject line. This will be used when asksub is off.

toplines

Type: Numeric.
Default: 5

Number of lines to be displayed by top and Top commands.

variable-strict
varstrict

Type: Boolean.
Default: False.

Setting this variable enables strict control over variable settings. In this mode, mail refuses to set read-only variables. Also, if the user is trying to set an unknown variable, mail prints a warning.

See Setting and Unsetting the Variables.

variable-pretty-print
varpp

Type: Boolean.
Default: False.

If this variable is set, the listing output by set contains short descriptions before each variable. See Setting and Unsetting the Variables.

verbose

Type: Boolean.
Default: False.

When set, the actual delivery of messages is displayed on the user’s terminal.

xmailer

Type: Boolean.
Default: Set.

Controls whether the header ‘X-Mailer’ should be added to outgoing messages. The default value of this header is

X-Mailer: mail (GNU Mailutils 3.5)

3.5.8 Personal and System-wide Configuration Files

After processing the usual Mailutils configuration files (see configuration), mail reads the contents of the two command files: the system-wide command file, and the user’s command file. Each line read from these files is processed like a usual mail command.

When run with --norc (-N) option, mail does not read the contents of system-wide configuration file. The user’s file, if it exists, is always processed.

The user’s configuration file is located in the user’s home directory and is named .mailrc. The location and name of the system-wide configuration file is determined when configuring the package via --with-mail-rc option. It defaults to sysconfdir/mail.rc.

3.6 messages — Count the Number of Messages in a Mailbox

Messages prints on standard output the number of messages contained in each folder specified in command line. If no folders are specified, it operates upon user’s system mailbox. For each folder, the following output line is produced:

Number of messages in folder: number

where folder represents the folder name, number represents the number of messages.

The following configuration file statements affect the behaviour of messages:

StatementReference
debugSee debug statement.
tlsSee tls statement.
mailboxSee mailbox statement.
lockingSee locking statement.

In addition to the common mailutils options (see Common Options), the program accepts the following command line options:

-q
--quiet
-s
--silent

Be quiet. Display only number of messages per mailbox, without leading text.

3.7 movemail — Moves Mail from the User Maildrop to the Local File

The purpose of movemail, as its name implies, is to move mail from one location to another. For example, the following invocation:

movemail /var/mail/smith INBOX

moves messages from file /var/mail/smith to file INBOX.

The program was initially intended as a replacement for movemail from GNU Emacs. The movemail program is run by Emacs Rmail module. See Rmail in Reading Mail with Rmail, for detailed description of Rmail interface.

Mailutils version of movemail is fully backward-compatible with its Emacs predecessor, so it should run flawlessly with older versions of Emacs. Emacs versions starting from 22.1 contain improved Rmail interface and are able to take advantage of all new features mailutils movemail provides.

Apart from that use, movemail proved to be a useful tool for incorporating mail from remote mailboxes into the local one. See Fetching Mail with Movemail, for a detailed discussion with usage recipes.

3.7.1 Movemail Configuration

The following configuration file statements affect the behavior of movemail:

Movemail Config: preserve bool

If bool is ‘true’, do not remove messages from the source mailbox.

Movemail Config: reverse bool

If bool is ‘true’, reverse message sorting order.

Movemail Config: emacs bool

If bool is ‘true’, output information used by Emacs rmail interface.

Movemail Config: ignore-errors bool

Continue moving messages after errors. By default, mailfromd exits immediately if it cannot copy a message.

Movemail Config: program-id fmt

Set program identifier, i.e. a string which will prefix all diagnostic messages issued by the program. By default, program name is used.

The fmt is a format string that may contain references to the following variables (see Variables):

progname

The program name.

source

URL of the source mailbox.

source_user

User part of the source mailbox URL.

source_host

Host part of the source mailbox URL.

source_path

Path part of the source mailbox URL.

dest

URL of the destination mailbox

dest_user

User part of the destination mailbox URL.

dest_host

Host part of the destination mailbox URL.

dest_path

Path part of the destination mailbox URL.

Setting program-id may be necessary if several movemail instances are run simultaneously (e.g. invoked from a script) to discern between the instances. For example:

program-id "${progname}: ${source} => ${dest}"
Movemail Config: uidl bool

Avoid copying the message if a message with the same UIDL already exists in the destination mailbox.

Movemail Config: verbose level

Set verbosity level.

Movemail Config: mailbox-ownership method-list

Define list of methods for setting ownership of the destination mailbox. The method-list argument can contain the following elements:

copy-id

Copy owner UID and GID from the source mailbox. This method works only with local mailboxes, i.e.: ‘mbox’ (UNIX mailbox), ‘maildir’ and ‘mh’.

copy-name

Get owner name from the source mailbox URL and obtain UID and GID for this user using mailutils authorization methods.

set-id=uid[:gid]

Set supplied uid and gid. If gid is not supplied, it is read from the /etc/passwd record for this UID.

set-name=user

Make destination mailbox owned by user.

Movemail Config: max-messages count

Defines upper limit on the number of moved messages. Movemail will stop after transferring count messages.

By default, the number of messages is not limited.

Movemail Config: onerror actions

Defines what to do if an error occurs when transferring a message. actions is a list of one or more of the following keywords:

abort

Abort the transfer and terminate the program. This is the default action.

skip

Skip to the next message.

delete

Delete the affected message.

count

Count this message as processed.

Each keyword can be prefixed with ‘no’ to reverse its meaning.

The following standard Mailutils statements are supported:

StatementReference
debugSee debug statement.
tlsSee tls statement.
mailboxSee mailbox statement.
lockingSee locking statement.
pamSee pam statement.
sqlSee sql statement.
virtdomainSee virtdomain statement.
radiusSee radius statement.
ldapSee ldap statement.
authSee auth statement.

3.7.2 Setting Destination Mailbox Ownership

Editor’s note:

The information in this node may be obsolete or otherwise inaccurate. This message will disappear, once this node revised.

3.7.3 Movemail Usage Summary

movemail [option...] inbox destfile [password]

The first argument, inbox, is the url (see Mailbox) of the source mailbox. The second argument, destfile, traditionally means destination file, i.e. the UNIX mailbox to copy messages to. However, mailutils movemail extends the meaning of this parameter. You may actually specify any valid url as destfile parameter.2.

For compatibility with older implementations of movemail, the source argument can also have the form:

po:username[:pop-server]

where pop-server is the IP address or hostname of a POP3 server to connect to and username is the name of the user on that server. The password is then supplied by the third argument.

It is equivalent to the following URL:

pop://username[:password]@pop-server

In fact, whenever source refers to a remote mailbox, the password argument can be used to pass the password. However, the safer ticket method is of course preferred.

Options are one or more of the following:

--emacs

Output information used by Emacs rmail interface.

--ignore-errors

Try to continue after errors.

--max-messages=count

Process at most count messages.

--notify

Enable biff notification.

--onerror=kw[,kw...]

What to do on errors. See onerror statement, for a description of kw.

-P modelist
--owner=modelist

Control mailbox ownership. modelist is a comma-separated list of one or more ownership change methods. See mailbox-ownership-methods, for a description of available methods.

This option is useful only when running movemail as root.

-p
--preserve
--keep-messages

Don’t remove transferred messages from the source mailbox.

--program-id=fmt

Set program identifier for diagnostics (default: the program name). See movemail-program-id, for a description of its argument.

-r
--reverse

Reverse the order of retrieved messages.

-u
--uidl

Use UIDLs to avoid downloading the same message twice.

-v
--verbose

Increase verbosity level.

The common options are also understood (see Common Options).

3.8 readmsg — Extract Messages from a Folder

The readmsg utility extracts messages from a mailbox according to the criteria specified in the command line. These criteria are:

  1. A lone ‘*’ means “select all messages in the mailbox”.
  2. A list of message numbers may be specified. Values of ‘0’ and ‘$’ in the list both mean the last message in the mailbox. For example:
    readmsg 1 3 0
    

    extracts three messages from the folder: the first, the third, and the last.

  3. Finally, the selection may be some text to match. This will select a mail message which exactly matches the specified text. For example,
    readmsg staff meeting
    

    extracts the message which contains the words ‘staff meeting’. Note that it will not match a message containing ‘Staff Meeting’ – the matching is case sensitive. Normally only the first message which matches the pattern is printed.

Unless one of the informational options is used, at least one command line argument must be present. Informational options are: --help (-?), --usage, and --version (-V).

3.8.1 Invocation of readmsg.

-a
--show-all

If a pattern is use for selection show all messages that match pattern by default only the first one is presented.

-d
--debug

Display mailbox debugging information.

-f mailbox
--folder=mailbox

Specified the default mailbox.

-h
--header

Show the entire header and ignore the weedlist.

-n
--no-header

Do not print the message header.

-p
--form-feed

Put form-feed (Control-L) between messages instead of newline.

-w weedlist
--weedlist=weedlist

A whitespace or coma separated list of header names to show per message. Default is --weedlist="From Subject Date To CC Apparently-".

See also Common Options.

3.8.2 Configuration of readmsg.

Following configuration statements affect the behavior of readmsg:

Readmsg Conf: header bool

If bool is ‘true’, display entire headers.

Readmsg Conf: weedlist str

Set the weedlist. The str argument is a string, containing a list of header names, separated by whitespace, commands or colons. This corresponds to the --weedlist command line option (see –weedlist).

Readmsg Conf: no-header bool

If bool is ‘true’, exclude all headers.

Readmsg Conf: form-feeds bool

If bool is ‘true’, output formfeed character between messages.

Readmsg Conf: folder url

Set the URL of the mailbox folder to read.

Readmsg Conf: show-all-match bool

If bool is ‘true’, print all messages matching pattern, not only the first.

StatementReference
debugSee Debug Statement.
tlsSee TLS Statement.
mailboxSee Mailbox Statement.
lockingSee Locking Statement.

3.9 sieve

Editor’s note:

The information in this node may be obsolete or otherwise inaccurate. This message will disappear, once this node revised.

Sieve is a language for filtering e-mail messages at time of final delivery, described in RFC 3028. GNU Mailutils contains stand-alone sieve interpreter, which is described in detail below.

3.9.1 A Sieve Interpreter

The sieve interpreter sieve allows you to apply Sieve scripts to arbitrary number of mailboxes. GNU sieve implements a superset of the Sieve language as described in RFC 3028. See Sieve Language, for a description of the Sieve language. See GNU Extensions, for a discussion of differences between the GNU implementation of Sieve and its standard.

3.9.1.1 Invoking sieve

The sieve invocation syntax is:

sieve [options] script

Normally, script is the name of the disk file with the Sieve script. If script is a single dash, the script is read from the standard input. If the -E (--expression) option is given, script is taken to be the sieve script text.

where script denotes the filename of the sieve program to parse, and options is one or more of the following:

-c
--compile-only

Compile script and exit.

--clear-library-path
--clearpath

Clear Sieve library path. See also clear-library-path.

--clear-include-path

Clear Sieve include path. See also clear-include-path.

-d[flags]
--debug[=flags]

Specify debug flags. The flags argument is a sequence of one or more of the following letters:

gEnable main parser traces
TEnable mailutils traces
PTrace network protocols
tEnable sieve trace
iTrace the program instructions
-D
--dump

Compile the script, dump disassembled code on standard output and exit.

--environment=name=value

Set sieve environment variable name to the value.

-e address
--email address

Override the user email address. This is useful for reject and redirect actions. By default, the user email address is deduced from the user name and the full name of the machine where sieve is executed. See also email.

-E,
--expression

Treat the script argument as Sieve program text.

-I dir
--includedir=dir

Append directory dir to the list of directories searched for include files. See also include-path.

-f
--mbox-url=mbox

Mailbox to sieve (defaults to user’s system mailbox). See also mbox-url.

-k
--keep-going

Keep on going if execution fails on a message. See also keep-going.

-L dir
--libdir=dir

Append directory dir to the list of directories searched for library files. See also library-path.

--libdir-prefix=dir

Add dir to the beginning of the list of directories searched for library files.

--line-info=bool

Print source location along with action logs (default).

-M url
--mailer=url

Define the URL of the default mailer.

-n
--no-actions
--dry-run

Dry run: do not execute any actions, just print what would be done.

--no-program-name

Do not prefix diagnostic messages with the program name.

-t ticket
--ticket=ticket

Ticket file for mailbox authentication. See also ticket.

--variable=name=value

Set Sieve variable name. This option automatically inserts ‘require "variables"’ at the top of the script.

-v
--verbose

Log all actions executed. See also verbose.

See also Common Options.

3.9.1.2 Sieve Configuration

The behavior of sieve is affected by the following configuration statements:

StatementReference
debugSee debug statement.
tlsSee tls statement.
mailboxSee mailbox statement.
lockingSee locking statement.
loggingSee logging statement.
mailerSee mailer statement.

The following statements configure sieve-specific features:

Sieve Conf: sieve { ... }

This block statement configures search paths sieve uses to locate its loadable modules. See Require Statement, for a detailed information about loadable modules.

This statement may contain the following sub-statements:

Sieve Conf: clear-library-path bool

If bool is ‘true’, clear library search path.

Sieve Conf: clear-include-path bool

If bool is ‘true’, clear include search path.

Sieve Conf: library-path path

Add directories to sieve library search path. Argument is a string containing a colon-separated list of directories.

Sieve Conf: library-path-prefix path

Add directories to the beginning if the library search path. Argument is a string containing a colon-separated list of directories.

Sieve Conf: include-path path

Add directories to the include search path. Argument is a string containing a colon-separated list of directories.

Sieve Conf: keep-going bool

If bool is ‘true’, do not abort if execution of a Sieve script fails on a particular message.

Sieve Conf: mbox-url url

Sets URL of the mailbox to be processed.

Sieve Conf: ticket file

Sets the name of the ticket file for user authentication.

Sieve Conf: debug flags

Sets Sieve debug flags. See Logging and Debugging, for a detailed description.

Sieve Conf: verbose bool

If bool is ‘true’, log all executed actions.

Sieve Conf: line-info bool

If bool is ‘true’, print source locations along with action logs. This statement takes effect only if verbose true is also set.

Sieve Conf: email addr

Set user e-mail address. This is useful for reject and redirect actions. By default, the user email address is deduced from the user name and the full name of the machine where sieve is executed.

3.9.1.3 Logging and debugging

The default behavior of sieve is to remain silent about anything except errors. However, it is sometimes necessary to see which actions are executed and on which messages. This is particularly useful when debugging the sieve scripts. The --verbose (-v) option outputs log of every action executed.

Option --debug allows to produce even more detailed debugging information. This option takes an argument specifying the debugging level to be enabled. The argument can consist of the following letters:

t

This flag enables sieve tracing. It means that every test will be logged when executed.

T

This flag enables debugging of underlying mailutils library.

P

Trace network protocols: produces log of network transactions executed while running the script.

g

Enable main parser traces. This is useful for debugging the sieve grammar.

i

Trace the program instructions. It is the most extensive debugging level. It produces the full execution log of a sieve program, showing each instruction and states of the sieve machine. It is only useful for debugging the code generator.

Note, that there should be no whitespace between the short variant of the option (-d), and its argument. Similarly, when using long option (--debug), its argument must be preceded by equal sign.

If the argument to --debug is omitted, it defaults to ‘TPt’.

Option --dump produces the disassembled dump of the compiled sieve program.

By default sieve outputs all diagnostics on standard error and verbose logs on standard output. This behaviour is changed when --log-facility is given in the command line (see logging). This option causes sieve to output its diagnostics to the given syslog facility.

3.9.1.4 Extending sieve

The basic set of sieve actions, tests and comparators may be extended using loadable extensions. The usual require mechanism is used for that.

When processing arguments for require statement, sieve uses the following algorithm:

  1. Look up the name in a symbol table. If the name begins with ‘comparator-’ it is looked up in the comparator table. If it begins with ‘test-’, the test table is searched instead. Otherwise the name is looked up in the action table.
  2. If the name is found, the search is terminated.
  3. Otherwise, transform the name. First, any ‘comparator-’ or ‘test-’ prefix is stripped. Then, any character other than alphanumeric characters, ‘.’ and ‘,’ is replaced with dash (‘-’). The name thus obtained is used as a file name of an external loadable module.
  4. Try to load the module. The module is searched in the following search paths (in the order given):
    1. Mailutils module directory. By default it is $prefix/lib/mailutils.
    2. The value of the environment variable LTDL_LIBRARY_PATH.
    3. Additional search directories specified with the. --libdir-prefix command line option (see libdir-prefix), or the library-path-prefix configuration statement (see library-path-prefix).
    4. Additional search directories specified with the library-path statement (see library-path) in Sieve configuration file.
    5. Additional search directories specified with the. --libdir command line option (see libdir).
    6. Additional search directories specified with the #searchpath Sieve directive (see #searchpath).
    7. System library search path: The system dependent library search path (e.g. on Linux it is set by the contents of the file /etc/ld.so.conf and the value of the environment variable LD_LIBRARY_PATH).

    The value of LTDL_LIBRARY_PATH and LD_LIBRARY_PATH must be a colon-separated list of absolute directories, for example, ‘"/usr/lib/mypkg:/lib/foo"’.

    In any of these directories, sieve first attempts to find and load the given filename. If this fails, it tries to append the following suffixes to the file name:

    1. the libtool archive extension ‘.la
    2. the extension used for native dynamic libraries on the host platform, e.g., ‘.so’, ‘.sl’, etc.
  5. If the module is found, sieve executes its initialization function (see below) and again looks up the name in the symbol table. If found, search terminates successfully.
  6. If either the module is not found, or the symbol wasn’t found after execution of the module initialization function, search is terminated with an error status. sieve then displays the following diagnostic message:
    source for the required action NAME is not available
    

3.10 guimb — A Mailbox Scanning and Processing Language

Guimb is an experimental tool that iterates over messages in a mailbox (or several mailboxes), applying a Scheme function to each of them.

A user-defined scheme module that supplies the function to apply is specified using the --source or --file option. The module must define at least the following function:

User function: guimb-message msg

Processes message msg. This function can alter the message using Guile primitives supplied by mailutils.

The following function definitions are optional:

User function: guimb-getopt args

If defined, this function is called after guimb has finished processing the command line. args is a list of unconsumed command line arguments.

The function is intended to provide a way of configuring the module from the command line.

User function: guimb-end

If defined, this function is called after all mailboxes have been processed.

In the following example we define a module that prints information about each message is the input mailbox, in a way similar to frm utility:

(define-module (frm)
  :export (guimb-message))

(use-modules (mailutils mailutils))
             
(define (guimb-message msg)
  (display (mu-message-get-sender msg))
  (display " ")
  (display (mu-message-get-header msg "subject"))
  (newline))

The modules are looked up in directories listed in the global variable %load-path. New directories can be added to that variable on the fly using the -L (--load-path) option. For example, if the sample module above was saved in a file frm.scm somewhere in the load path, it can be applied to the current user inbox by running the following command:

guimb --file frm

Specifying Scheme Program to Execute

Specifying Scheme Program to Execute

The Scheme module that defines message processing functions is given via the following options:

-s module
--source module

Load Scheme code from module.

This option stops further argument processing, and passes all remaining arguments as the value of args argument to the guimb-getopt function, if it is defined.

-f module
--file module

Load Scheme source code from module. The remaining arguments are processed in the usual way. When using this option, you can pass additional options and or arguments to the module by enclosing them in -{ and -} options (see Passing Options to Scheme).

An experimental option is provided, that evaluates a supplied Scheme expression right after loading the module:

-e expr
--expression expr

Evaluate scheme expression.

Specifying Mailboxes to Operate Upon

Specifying Mailboxes to Operate Upon

There are four basic ways of passing mailboxes to guimb.

guimb [options] [mailbox...]

The resulting mailbox is not saved, unless the user-supplied scheme program saves it.

guimb [options] --mailbox defmbox

The contents of defmbox is processed and is replaced with the resulting mailbox contents. Useful for applying filters to user’s mailbox.

guimb [options] --mailbox defmbox mailbox [mailbox...]

The contents of specified mailboxes is processed, and the resulting mailbox contents is appended to defmbox.

guimb [options] --user username [mailbox...]

The contents of specified mailboxes is processed, and the resulting mailbox contents is appended to the user’s system mailbox. This makes it possible to use guimb as a mail delivery agent.

If no mailboxes are specified in the command line, guimb reads and processes the system mailbox of the current user.

Passing Options to Scheme

Passing Options to Scheme

Sometimes it is necessary to pass some command line options to the scheme procedure. There are three ways of doing so.

When using --source (-s) option, the rest of the command line following the option’s argument is passed as the args argument to the guimb-getopt function, if such function is defined. This allows for making guimb scripts executable by the shell. If your system supports ‘#!’ magic at the start of scripts, add the following two lines to the beginning of your script to allow for its immediate execution:

#! /usr/local/bin/guimb -s
!#

(replace ‘/usr/local/bin/’ with the actual path to the guimb).

Otherwise, if you use the --file option, the additional arguments can be passed to the Scheme program -g (--guile-arg) command line option. For example:

guimb --guile-arg -opt --guile-arg 24 --file progfile

In this example, the guimb-getopt function will get the following argument

( '-opt' 24 )

Finally, if there are many arguments to be passed to Scheme, it is more convenient to enclose them in -{ and -} escapes:

guimb -{ -opt 24 -} --file progfile

Command Line Option Summary

Command Line Option Summary

This is a short summary of the command line options available to guimb.

-d
--debug

Start with debugging evaluator and backtraces.

-e expr
--expression expr

Execute given Scheme expression.

-L dir
--load-path dir

Insert dir at the beginning of the %load-path list. The argument is either a single directory name, or a list of such names, delimited by ‘:’ characters.

-m path
--mail-spool=path

Set path to the mailspool directory

-f progfile
--file progfile

Read Scheme program from progfile.

-g arg
--guile-command arg

Append arg to the command line passed to Scheme program.

-{ ... -}

Pass all command line options enclosed between -{ and -} to Scheme program.

-m
--mailbox mbox

Set default mailbox name.

-u
--user name

Act as local MDA for user name.

-h
--help

Display help message.

-v
--version

Display program version.

3.11 maidag

Editor’s note:

The information in this node may be obsolete or otherwise inaccurate. This message will disappear, once this node revised.

The name ‘maidag’ stands for Mail delivery agent. It is a general-purpose MDA offering a rich set of features. It can operate both in traditional mode, reading the message from its standard input, and in LMTP mode. Maidag is able to deliver mail to any mailbox format, supported by GNU Mailutils. These formats, among others, include ‘smtp://’, ‘prog://’ and ‘sendmail://’ which are equivalent to forwarding a message over SMTP to a remote node. Thus, maidag supersedes both mail.local and mail.remote utilities from GNU Mailutils versions prior to 2.0.

Maidag is also able to process incoming messages using Sieve, Scheme or Python scripts and, based on results of this processing, to take a decision on whether to actually deliver and where to deliver them. Due to its extensive scripting facilities, maidag offers much more flexibility than other popular MDAs, such as procmail.

3.11.1 Using maidag with Sendmail.

When used as a MDA with Sendmail, maidag must be invoked from the local mailer definition in the sendmail.cf file. It must have the following flags set: ‘lswS’. These mean: the mailer is local, quote characters should be stripped off the address before invoking the mailer, the user must have a valid account on this machine and the userid should not be reset before calling the mailer. Additionally, the flags ‘fn’ may be specified to allow maidag to generate the usual ‘From ’ envelope instead of the one supplied by sendmail.

If you wish to use maidag with non-local authentication, such as SQL or LDAP, you also need to remove the ‘w’ flag, since in that case the user is not required to have a valid account on the machine that runs sendmail.

Here is an example of mailer definition in sendmail.cf

Mlocal, P=/usr/local/sbin/maidag,
        F=lsDFMAw5:/|@qSPfhn9,
        S=EnvFromL/HdrFromL, R=EnvToL/HdrToL,
        T=DNS/RFC822/X-Unix,
        A=mail $u

To define local mailer in ‘mc’ source file, it will suffice to set:

define(`LOCAL_MAILER_PATH', `/usr/local/sbin/maidag')
define(`LOCAL_MAILER_ARGS', `mail $u')

3.11.2 Using maidag with Exim.

Using maidag with Exim is quite straightforward. The following example illustrates the definition of the appropriate transport and director in exim.conf:

# transport
maidag_pipe:
  driver = pipe
  command = /usr/local/sbin/maidag $local_part
  return_path_add
  delivery_date_add
  envelope_to_add
  
# director
maidag:
  driver = localuser
  transport = maidag_pipe

3.11.3 Using maidag with MeTA1.

MeTA1 (http://meta1.org) communicates with the delivery agent using LMTP.

LMTP mode is enabled in maidag by the ‘lmtp yes’ statement. The socket to listen on must be specified using server statement (see Server Settings). For the purposes of this section, let’s suppose maidag will listen on a UNIX socket /var/spool/meta1/lmtpsock. Then, the following (minimal) maidag configuration will do the job:

# Start in LMTP mode.
lmtp yes;
# Run as daemon.
mode daemon;
# Switch to this group after startup.
group meta1c;
# Configure server:
server unix:///var/spool/meta1/lmtpsock {
  transcript no;
};

To configure MeTA1 to use this socket, add the following statement to the ‘smtpc’ section in /etc/meta1/meta1.conf:

  LMTP_socket="lmtpsock";

3.11.4 Mailbox Quotas

Mailbox quota is a limit on the size of the mailbox. When a mailbox size reaches this limit, maidag stops accepting messages for this recipient and returns an error condition to the sender. The error code is accompanied by the following error message:

user: mailbox quota exceeded for this recipient

Furthermore, if accepting the incoming message would make the mailbox size exceed the quota, such a message will be rejected as well. In this case, the error message is:

user: message would exceed maximum mailbox size for this recipient

In both cases, the default return code will be ‘service unavailable’ (corresponding to the SMTP return code ‘550’), unless the following statement is present in the maidag configuration file:

exit-quota-tempfail yes;

in which case a temporary error will be returned.

The mailbox quota can be retrieved from the following sources:

  1. Authentication method.
  2. DBM file.
  3. SQL database.

3.11.4.1 Keeping Quotas in DBM File

To use DBM quota database, GNU Mailutils must be compiled with one of the following command line options: --with-gdbm, --with-berkeley-db, --with-ndbm, --with-tokyocabinet, or --with-kyotocabinet. Examine the output of maidag --show-config-options, if not sure.

The quota database should have the following structure:

Key

Key represents the user name. Special key ‘DEFAULT’ means default quota value, i.e. the one to be used if the user is not explicitly listed in the database.

Value

Mailbox quota for this user. If it is a number, it represents the maximum mailbox size in bytes. A number may optionally be followed by ‘kb’ or ‘mb’, meaning kilobytes and megabytes, respectively.

A special value ‘NONE’ means no mailbox size limit for this user.

Here is an example of a valid quota database

# Default quota value:
DEFAULT         5mb

# Following users have unlimited mailbox size
root            NONE
smith           NONE

# Rest of users
plog            26214400
karin           10mB

To use the DBM quota database, specify its absolute name using quota-db configuration statement, e.g.:

quota-db /etc/mail/quota.db;

3.11.4.2 Keeping Quotas in SQL Database

Configuration statement quota-query allows to specify a special query to retrieve the quota from the database. Currently (as of mailutils version 3.5) it is assumed that this table can be accessed using the credentials set in ‘sql’ configuration statement (see SQL Statement).

For example, suppose you have the following quota table:

create table mailbox_quota (
  user_name varchar(32) binary not null,
  quota int,
  unique (user_name)
);

To retrieve user quota the following query can be used:

SELECT quota FROM mailbox_quota WHERE user_name='${user}'

There are no special provisions for specifying group quotas, similar to ‘DEFAULT’ in DBM databases. This is because group quotas can easily be implemented using SQL language. Maidag always uses the first tuple from the set returned by mailbox quota query. So, you may add a special entry to the mailbox_quota table that would keep the group quota. In the discussion below we assume that the user_name column for this entry is lexicographically less than any other user name in the table. Let’s suppose the group quota name is ‘00DEFAULT’. Then the following query:

SELECT quota
FROM mailbox_quota
WHERE user_name IN ('${user}','00DEFAULT')
ORDER BY user_name DESC

will return two tuples if the user is found in mailbox_quota. Due to ORDER statement, the first tuple will contain the quota for the user, which will be used by maidag. On the other hand, if the requested user name is not present in the table, the above query will return a single tuple containing the group quota.

The following configuration statement instructs maidag to use this query for retrieving the user quota:

quota-query "SELECT quota "
            "FROM mailbox_quota "
            "WHERE user_name IN ('${user}','00DEFAULT') "
            "ORDER BY user_name DESC";

3.11.5 Maidag Scripting

Maidag can use global or per-user mail filters to decide whether to deliver the message, and where to deliver it. As of Mailutils version 3.5, such mail filters may be written in the following languages:

Mail filters to use are specified using ‘script’ configuration statement. The following meta-symbols can be used in its argument:

~
%h

Expands to the recipient home directory.

%u

Expands to the recipient user name.

By default, the filename extension decides which scripting language will be used. User can alter the choice using ‘language’ configuration statement. For example:

language "python"
script "~/.maidag-py-filter"

3.11.5.1 Sieve Maidag Filters

The file name of the Sieve filter to use is specified using ‘script’ configuration statement. For example, the following configuration statement:

script "~/.maidag.sv"

instructs maidag to use file .maidag.sv in the recipient home directory as a Sieve filter.

Normal message delivery is attempted if execution of the Sieve code ended with keep action (either implicit or explicit).

Other Sieve actions are executed as described in Actions. For example, to deliver message to another mailbox, use the fileinto action.

Any modifications to headers or body of the message performed by the Sieve code will be visible in the delivered message.

3.11.5.2 Scheme Maidag Filters

The file name of the Scheme mail filter is specified using ‘script’ configuration statement. For example, the following configuration statement:

script "~/.maidag.scm"

instructs ‘maidag’ to use file ‘.maidag.scm’ in the recipient home directory as a Scheme filter.

3.11.5.3 Python Maidag Filters

The file name of the Python mail filter is specified using ‘script’ configuration statement. For example, the following configuration statement:

script "~/.maidag.py"

instructs ‘maidag’ to use file ‘.maidag.py’ in the recipient home directory as a Python filter.

A simple example of a mail filter written in Python:

from mailutils import *
import maidag
import re

msg = message.Message (maidag.message)
hdr = msg.header

try:
    if 'List-Post' in hdr and 'Received' in hdr \
       and hdr['Received'].find ('fencepost.gnu.org') != -1:

        # check envelope's sender address
        m = re.search (r'([\w\-]+)-bounces\+([\w]+)=.*',
                       msg.envelope.get_sender ())
        if m:
            lbox = m.group (1)
            user = m.group (2)
            # open destination mailbox and append message
            dst = mailbox.MailboxDefault ('~/Mail/%s' % lbox)
            dst.open ('ac')
            dst.append_message (msg)
            dst.close ()
            # set deleted flag so maidag will not deliver msg elsewhere
            msg.attribute.set_deleted ()
except Exception:
    pass

3.11.6 Forwarding

Forward file is a special file in the user’s home directory that contains the email address of the mailbox where the user wants to forward his mail. Normally, forward files are processed by MTA. However, there are some MTA that lack this feature. One of them is MeTA1.

Maidag provides a forwarding feature that is useful to compensate the lack of it.

Name of the forward file is given using forward-file configuration statement. A common usage is:

forward-file .forward;

The forward file is always searched in the recipient home directory.

Before actually using the file, a number of safety checks are performed on it. If the file fails to pass one of these checks, no forwarding is performed and the message is delivered as usual. These checks can be configured using forward-file-checks statement. Its argument is a list of the following keywords:

groupwritablefile
file_iwgrp

The file must not be group writable.

worldwritablefile
file_iwoth

The file must not be world writable.

linkedfileinwritabledir
link

The file cannot be a symlink in a writable directory.

fileingroupwritabledir
dir_iwgrp

The file cannot reside in a group writable directory.

fileinworldwritabledir
dir_iwoth

The file cannot reside in a world writable directory.

all

All of the above checks.

The default is ‘forward-file-checks all’.

Each of these keywords may be prefixed by ‘no’ to disable this particular check. For example:

forward-file-checks (nodir_iwoth, nodir_iwgrp);

3.11.7 Delivering Messages to a URL.

When invoked with the --url command line option, maidag treats its arguments as a list of mailbox URLs and attempts to deliver the message to each of them.

For example:

$ maidag --url maildir:///home/smith/Mail

3.11.8 Remote Mailbox Delivery

Maidag can be used to deliver mail to remote mailboxes, such as ‘imap’ or ‘smtp’. If the mailbox URL is ‘smtp’ or ‘sendmail’, the message is actually forwarded over SMTP to the remote node, so maidag acts as a message transfer agent. For example:

$ maidag --url smtp://10.10.1.100:24

This command line will send the message to the machine ‘10.10.1.100’ using port ‘24’ (private mail system).

The ‘prog’ mailbox may be of special use. Delivering to this mailbox results in invoking the specified command with the given arguments and passing the message to its standard input. There are two ways to specify a ‘prog’ mailbox:

prog://program?args

Here, program is the absolute pathname of the program binary, and args are its arguments, separated by ‘&’ signs.

|program args

In this notation, args are command line arguments separated by white space.

In both cases, args do not include argv[0].

The ‘prog’ mailbox may be used, in particular, to implement mailing lists with MeTA1.

For example, suppose that the maidag configuration contains:

auth {
  authorization sql:system;
  authentication generic:system;
}

sql {
  interface mysql;
  db mail;
  getpwnam "SELECT user as name, mailbox, "
           "'x' as passwd, 500 as uid, 2 as gid, "
           "'/nonexistent' as dir, '/sbin/nologin' as shell "
           "FROM userdb "
           "WHERE user='${user}'";
}

Then, the following entries in the ‘userdb’ table implement mailman@yourdomain mailing list:

mysql> select * from userdb;
+---------------------+---------------------------------------+
| user                | mailbox                               |
+---------------------+---------------------------------------+
| mailman             | |/usr/bin/mailman post mailman        |
| mailman-admin       | |/usr/bin/mailman admin mailman       |
| mailman-bounces     | |/usr/bin/mailman bounces mailman     |
| mailman-confirm     | |/usr/bin/mailman confirm mailman     |
| mailman-join        | |/usr/bin/mailman join mailman        |
| mailman-leave       | |/usr/bin/mailman leave mailman       |
| mailman-owner       | |/usr/bin/mailman owner mailman       |
| mailman-request     | |/usr/bin/mailman request mailman     |
| mailman-subscribe   | |/usr/bin/mailman subscribe mailman   |
| mailman-unsubscribe | |/usr/bin/mailman unsubscribe mailman |
+---------------------+---------------------------------------+

3.11.9 Maidag Configuration File Summary

The behavior of maidag is affected by the following configuration statements:

StatementReference
debugSee debug statement.
mailboxSee mailbox statement.
lockingSee locking statement.
pamSee pam statement.
sqlSee sql statement.
virtdomainSee virtdomain statement.
radiusSee radius statement.
ldapSee ldap statement.
authSee auth statement.
mailerSee mailer statement.
serverSee Server Settings. Used only in LMTP mode.
aclSee acl statement.
tcp-wrappersSee tcp-wrappers statement.
Maidag Config: ex-multiple-delivery-success bool

In case of multiple delivery, exit with code 0 if at least one delivery has succeeded.

Maidag Config: ex-quota-tempfail bool

Indicate temporary failure if the recipient is over his mail quota. By default, permanent failure is returned. See Mailbox Quotas.

Maidag Config: quota-db file

Set the name of DBM quota database file. See DBM Quotas.

Maidag Config: sieve-filter pattern

Set file name or name pattern of the Sieve filter file. See Sieve Maidag Filters.

Maidag Config: message-id-header name

When logging Sieve actions, identify messages by the value of this header.

Maidag Config: guile-filter pattern

File name or name pattern for Guile filter file. See Scheme Maidag Filters.

Maidag Config: debug flags

Set additional debugging flags. Valid flags are:

g

Print guimb stack traces.

t

Enable sieve trace (MU_SIEVE_DEBUG_TRACE).

i

Enable sieve instructions trace (MU_SIEVE_DEBUG_INSTR).

l

Log executed Sieve actions.

Maidag Config: stderr bool

Log to stderr instead of syslog.

Maidag Config: forward-file file

Process forward file file. See Forwarding.

Maidag Config: forward-file-checks list

Configure safety checks for the forward file. See forward-file-checks.

Maidag Config: lmtp bool

Run in LMTP mode.

Maidag Config: group list

In LMTP mode, retain supplementary groups from list.

Maidag Config: listen url

In LMTP mode, listen on url. Valid URLs are: ‘tcp://host:port’ (note that port is mandatory), ‘file://socket-file-name’ or ‘socket://socket-file-name’.

Maidag Config: reuse-address bool

Reuse existing address (LMTP mode). Default is ‘yes’.

3.12 mimeview

For each file given in its command line, mimeview attempts to autodetect its type and invoke an appropriate file viewer.

To detect the file type, mimeview uses mime.types file. This file is a part of Common UNIX Printing System, mime.types in mime.types man page. By default mimeview searches for mime.types in $prefix/etc/cups/3, however its exact location can be specified at runtime as well (see --mimetypes below).

Once file MIME type is successfully determined, mimeview consults mailcap files in order to determine how to display the file. It does so essentially in the same manner as metamail utility, i.e., it scans all files specified in METAMAIL environment variable until it finds an entry describing the desired file format or until the list of files is exhausted. If METAMAIL variable is not set, mimeview uses the following default path instead:

$HOME/.mailcap:/usr/local/etc/mailcap:\
 /usr/etc/mailcap:/etc/mailcap:\
 /etc/mail/mailcap:/usr/public/lib/mailcap

3.12.1 Mimeview Invocation

The following table summarizes options specific for mimeview:

-a[type-list]
--no-ask[=type-list]

By default mimeview asks for confirmation before running interpreter to view a message. If this option is used without argument, it disables the default behavior for all message types. Otherwise, if argument type-list is given, it specifies a comma-separated list of MIME types for which no questions should be asked. Elements of this list may include shell-style globbing patterns, e.g. setting

--no-ask='text/*,image/jpeg'

will disable prompting before displaying any textual files, no matter what their subtype is, and before displaying files with type ‘image/jpeg’.

Notice, that when the long form is used, its argument must be separated from the option by a single equal sign, as shown in the example above. When the short form (-a) is used, its argument must follow the option immediately, without any intervening whitespace, e.g. -a'text/*').

-d[flags]
--debug[=flags]

Enables debugging output. Flags is a sequence of characters specifying the desired debugging level. Following characters are meaningful in flags:

g

Enables debugging of mime.types parser

l

Enables debugging of mime.types lexical analyzer (warning: produces very copious output)

0

Prints basic information about actions to be executed and reports about exit status of executed commands.

1

Additionally displays each file name along with its MIME type

2

Additionally traces the process of looking up the matching entry in mailcap files.

3

Additionally, enables debugging of mime.types parser (‘g’).

4

Additionally, enables debugging of mime.types lexer (‘l’).

digits from 5 to 9

The same as 4, currently.

If flags are not given, the default ‘2’ is assumed.

--metamail[=file]

Run metamail to display files, instead of using the internal mechanisms. If file is specified, it is taken as metamail command line.

-h
--no-interactive
--print

This options tells mimeview that it should run in non-interactive mode. In this mode prompting is disabled, and the normal mailcap command field is not executed. Instead mimeview will execute the command specified in the print field. If there is nothing in the print field, the mailcap entry is ignored and the search continues for a matching mailcap entry that does have a print field.

Notice, that unlike in metamail -h, this option does not force mimeview to send the output to the printer daemon.

When used with --metamail option, this option passes -h flag to the invocation of metamail.

By default mimeview behaves as if given --no-interactive option whenever its standard input is not a tty device.

-i
--identify

Identifies and prints the MIME type for each input file.

-n
--dry-run

Do not do anything, just print what would be done. Implies --debug=1, unless the debugging level is set up explicitly.

-f file
--mimetypes file

Use file as mime.types file. If file is a directory, use file/mime.types

-t
--lint

Check syntax of the mime.types file and exit. Command line arguments are ignored.

3.12.2 Mimeview Config

The following configuration statements affect the behavior of mimeview:

StatementReference
debugSee Debug Statement.
Mimeview Config: mimetypes file

Read file instead of the default mime.types.

Mimeview Config: metamail program

Use program to display files.

3.13 POP3 Daemon

The pop3d daemon implements the Post Office Protocol Version 3 server.

pop3d has two operation modes:

Inetd

The server is started from /etc/inetd.conf file:

pop3  stream tcp nowait  root  /usr/local/sbin/pop3d pop3d

This is the default operation mode.

Standalone

The server runs as daemon, forking a child for each new connection.

The server operation mode is configured using mode statement (see mode).

3.13.1 Login delay

POP3 clients often login frequently to check for new mail. Each new connection implies authenticating the user and opening his maildrop and can be very resource consuming. To reduce server load, it is possible to impose a minimum delay between any two consecutive logins. This is called ‘LOGIN-DELAY’ capability and is described in RFC 2449.

As of version 3.5, GNU Mailutils pop3d allows to set global login delay, i.e. such enforcement will affect all POP3 users. If a user attempts to log in before the specified login delay expires, he will get the following error message:

-ERR [LOGIN-DELAY] Attempt to log in within the minimum login delay interval

The message will be issued after a valid password is entered. This prevents this feature from being used by malicious clients for account harvesting.

To enable the login delay capability, specify the minimum delay using login-delay configuration statement, e.g.:

login-delay 60;

The pop3d utility keeps each user’s last login time in a special DBM file, called login statistics database, so to be able to use this feature, Mailutils must be compiled with DBM support. By default, the login statistics database is called /var/run/pop3-login.db. You can change its name using stat-file configuration statement:

login-delay 60;
stat-file /tmp/pop.login.db;

The login delay facility will be enabled only if pop3d is able to access the statistics database for both reading and writing. If it is not, it will report this using syslog and start up without login delay restrictions. A common error message looks like:

Unable to open statistics db: Operation not permitted

You can check whether your pop3d uses login delays by connecting to it and issuing the ‘CAPA’ command. If login delays are in use, there response will contain the string ‘LOGIN-DELAY n’, where n is the actual login delay value.

3.13.2 Auto-expire

Automatic expiration of messages allows you to limit the period of time users are permitted to keep their messages on the server. It is enabled by expire configuration statement:

expire n;

Enable automatic expiration of messages after n days.

The current implementation works as follows. When a message is downloaded by RETR or TOP command, it is marked with ‘X-Expire-Timestamp: n’ header, where n is current value of UNIX timestamp. The exact expiration mechanism depends on you. Mailutils allows you two options:

  1. Expired messages are deleted by pop3d upon closing the mailbox. You specify this mechanism using delete-expired configuration statement:
    delete-expired bool;

    If bool is ‘true’, delete expired messages after receiving the QUIT command.

  2. Expired messages remain in the mailbox after closing it. The system administrator is supposed to run a cron job that purges the mailboxes. Such a cron job can be easily implemented using sieve from GNU Mailutils and the following script:
    require "timestamp";
    # Replace "5" with the desired expiration period
    if timestamp :before "X-Expire-Timestamp" "now - 5 days"
      {
        discard;
      }
    

    This script will remove expired messages 5 days after the retrieval. Replace ‘5’ with the desired expiration period and make sure it equals the argument to expire configuration keyword.

The statement expire 0 means the client is not permitted to leave mail on the server. It always implies delete-expired true.

3.13.3 Bulletins

The bulletin feature allows you to send important announcements to all POP3 users without mailing them. It works by creating a bulletin source mailbox and sending the announcements to it.

After a user successfully authenticates, pop3d checks the last bulletin number the user receives. The bulletin number refers to the number of the bulletin message in the bulletin source mailbox. If the latter contains more messages, these are appended to the user mailbox.

The user last bulletin number can be kept in two places. First, it can be stored in file .popbull in his home directory. Secondly, if Mailutils is compiled with DBM support, the numbers can be kept in a DBM file, supplied via bulletin-db configuration statement. If both the database and the .popbull file are present, the data from the database take precedence.

To enable this feature, use the following configuration statements:

bulletin-source mbox

Set the URL of the bulletin source mailbox.

bulletin-db file

Set the name of the database file to keep last bulletin numbers in.

The following example instructs pop3d to look for the bulletin messages in MH folder /var/spool/bull/mbox and to keep the database of last delivered bulletin numbers in /var/spool/bull/numbers.db:

bulletin-source mh:/var/spool/bull/mbox;
bulletin-db /var/spool/bull/numbers.db;

3.13.4 Pop3d Configuration

The following configuration file statements affect the behavior of pop3d.

StatementReference
debugSee debug statement.
tlsSee tls statement.
tls-file-checksSee tls-file-checks statement.
mailboxSee mailbox statement.
lockingSee locking statement.
loggingSee logging statement.
pamSee pam statement.
sqlSee sql statement.
virtdomainSee virtdomain statement.
radiusSee radius statement.
ldapSee ldap statement.
authSee auth statement.
serverSee Server Settings.
aclSee acl statement.
tcp-wrappersSee tcp-wrappers statement.
Pop3d Conf: undelete bool

On startup, clear deletion marks from all the messages.

Pop3d Conf: expire n

Automatically expire read messages after n days. See Auto-expire, for a detailed description.

Pop3d Conf: delete-expired bool

Delete expired messages upon closing the mailbox. See Auto-expire, for a detailed description.

Pop3d Conf: tls-required bool

Always require STLS command before entering authentication phase.

Pop3d Conf: login-delay duration

Set the minimal allowed delay between two successive logins. See Login delay, for more information.

Pop3d Conf: stat-file file

Set the name of login statistics file for the login-delay facility. See Login delay, for more information.

Pop3d Conf: bulletin-source file

Get bulletins from the specified mailbox. See Bulletins, for a detailed description.

Pop3d Conf: bulletin-db file

Set bulletin database file name. See Bulletins, for a detailed description.

3.13.5 Command line options

The following table summarizes all pop3d command line options.

-d[number]
--daemon[=number]

Run in standalone mode. An optional number specifies the maximum number of child processes allowed to run simultaneously. When it is omitted, it defaults to 10 processes. Please note, that there should be no whitespace between the -d and its parameter.

-i
--inetd

Run in inetd mode.

--foreground

Remain in foreground.

The Mailutils common options are also understood. See Common Options.

3.14 IMAP4 Daemon

GNU imap4d is a daemon implementing IMAP4 rev1 protocol for accessing and handling electronic mail messages on a server. It can be run either as a standalone program or from inetd.conf file.

3.14.1 Namespace

GNU imap4d supports a notion of namespaces defined in RFC 2342. A namespace can be regarded as a list of entities, defining locations to which the user has certain access rights. Each entity includes the prefix, under which the mailboxes can be found, hierarchy delimiter, a character used to delimit parts of a path to a mailbox, and a directory on the file system on the server, which actually holds the mailboxes. Among these three values, only first two are visible to the client using the IMAP ‘NAMESPACE’ command.

There are three namespaces:

Personal Namespace

A namespace that is within the personal scope of the authenticated user on a particular connection. The user has all permissions on this namespace.

By default, this namespace contains a single prefix:

prefix: ""
delimiter: /
directory: home directory of the user
Other Users’ Namespace

A namespace that consists of mailboxes from the “Personal Namespaces” of other users. The user can read and list mailboxes from this namespace. However, he is not allowed to use ‘%’ and ‘*’ wildcards with LIST command, that is he can access a mailbox only if he knows exactly its location.

By default, this namespace is empty.

Shared Namespace

A namespace that consists of mailboxes that are intended to be shared amongst users and do not exist within a user’s Personal Namespace. The user has all permissions on this namespace.

By default, this namespace is empty.

The default values ensure that each user is able to see or otherwise access mailboxes residing in the directories other than his own home.

These defaults can be changed using the namespace block statement:

namespace name {
    mailbox-mode mode;
    prefix pfx {
      directory path;
      delimiter chr;
      mailbox-type type;
    }
}

The name argument to the namespace statement declares which namespace is being configured. Allowed values are: ‘personal’, ‘other’, and ‘shared’.

The mailbox-mode statement configures the file mode for the mailboxes created within that namespace (provided that the directory permissions allow the user to create mailboxes). The mode argument is a comma-delimited list of symbolic mode settings, similar to that used by chmod. Each setting begins with a letter ‘g’, which means set mode bits for file group, or ‘o’, which means set mode bits for other users (note, that there is no ‘u’ specifier, since user ownership of his mailbox cannot be changed). This letter is followed by an ‘=’ (or ‘+’), and a list of modes to be set. This list can contain only two letters: ‘r’ to set read permission, and ‘w’ to set write permission.

For example, the following statement sets read and write permissions for the group:

mailbox-mode g=rw;

The prefix statement configures available prefixes and determines their mappings to the server’s file system. The pfx argument defines the prefix which will be visible to the IMAP client.

The directory statement defines the directory in the file system to which pfx is mapped. Exactly one directory statement must be present in each prefix block. The inerpretation of its argument depends on the namespace in which it occurs.

When used in the ‘namespace shared’ block, the argument to this statement is interpreted verbatim, as an absolute pathname.

When used in ‘namespace personal’ the argument to directory statement can contain references to the following variables (see Variables):

user

Login name of the user.

home

Home directory of the user.

For example, the following statement maps the default personal namespace to the directory ‘imap’ in the user’s home directory:

namespace personal {
  prefix "";
  directory "$home/imap";
}

If the ‘directory’ statement is used within the ‘namespace other’ block, its value can contain the ‘$user’ and ‘$home’ variables as well, but their meaning is different. For the ‘other’ namespace, the ‘$user’ variable is expanded to the part of the actual reference contained between the prefix and first hierarchy delimiter (or the end of the reference, if no delimiter occurs to the right of the prefix). Correspondingly, ‘$home’ expands to the home directory of that user. Consider, for example, the following statement:

namespace other {
  prefix "~";
  directory "/var/imap/$user";
}  

If the client issues the following statement:

1 LIST "~smith" "%"

then ‘$user’ will expand to the string ‘smith’ and the server will look for all mailboxes in the directory /var/imap/smith.

The delimiter statement defines the folder hierarchy delimiter for that prefix. It is optional, the default value being ‘"/"’.

The mailbox-type statement declares the type of the mailboxes within that prefix. If present, its argument must be a valid mailbox type (e.g. ‘mailbox’, ‘maildir’, or ‘mh’). The IMAP LIST command will display only mailboxes of that type. The CREATE command will create mailboxes of that type.

In the absence of the mailbox-type statement, the IMAP LIST command will display mailboxes of any type supported by Mailutils. The type of newly-created mailboxes is then determined by the mailbox-type statement (see mailbox-type).

Any number of prefix blocks can be present.

Consider, for example, the following configuration:

namespace personal {
   prefix "" {
      directory "$home/mailfolder";
   }   
   prefix "#MH:" {
      directory "$home/Mail";
      delimiter "/";
      mailbox-type "mh";
   }
}

It defines the personal namespace containing two prefixes. The empty prefix is mapped to the directory mailfolder in the home directory of the currently authenticated user. Any type of mailboxes is supported within that prefix.

The prefix ‘#MH:’ is mapped to the directory Mail in the home directory of the user, and is limited to contain only mailboxes in MH format.

Note that if the prefixes ‘""’ is not defined in the personal namespace, the following default will be automatically created:

prefix "" {
  directory "$home";
}

3.14.2 Configuration of imap4d.

The behavior of imap4d is altered by the following configuration statements:

StatementReference
debugSee debug statement.
tlsSee tls statement.
tls-file-checksSee tls-file-checks statement.
mailboxSee mailbox statement.
lockingSee locking statement.
loggingSee logging statement.
pamSee pam statement.
sqlSee sql statement.
virtdomainSee virtdomain statement.
radiusSee radius statement.
ldapSee ldap statement.
authSee auth statement.
serverSee Server Settings.
aclSee acl statement.
tcp-wrappersSee tcp-wrappers statement.
Imap4d Conf: namespace name { ... }

Configures namespace. The argument is one of: ‘personal’, ‘other’, ‘shared’. The following statements (described below) are allowed within curly braces: mailbox-mode and prefix.

See Namespace.

Imap4d namespace: mailbox-mode mode

Configures the file mode for the mailboxes created within that namespace. The syntax for mode is:

g(+|=)[wr]+,o(+|=)[wr]+

See mailbox-mode.

Imap4d namespace: prefix pfx { ... }

Configures a prefix and determines its mapping to the server’s file system. The pfx argument is the prefix which will be visible to the IMAP client. Available sub-statements are: directory, delimiter, and mailbox-type.

See prefix.

Imap4d namespace.prefix: directory path

Defines the directory in the file system to which the prefix is mapped.

See directory.

Imap4d namespace.prefix: delimiter chr

Defines the folder hierarchy delimiter for the prefix. Argument must be a single character.

See delimiter.

Imap4d namespace.prefix: mailbox-type type

Defines the type of the mailboxes inside that prefix.

See mailbox-type.

Imap4d Conf: login-disabled bool

Disable LOGIN command, if bool is ‘true’.

Imap4d Conf: create-home-dir bool

Create nonexistent user home directories. See also home-dir-mode, below.

Imap4d Conf: home-dir-mode mode

Set file mode for created user home directories. Mode is specified in octal.

The default value for mode is ‘700’ (‘drwx------’ in ls terms).

Imap4d Conf: preauth mode

Configure PREAUTH mode. Valid arguments are:

prog:///program-name

Imap4d invokes an external program to authenticate the connection. The command line is obtained from the supplied string, by expanding the following meta-variables:

${client_address}

Remote IP address in dotted-quad notation;

${client_port}

Remote port number;

${server_address}

Local IP address;

${server_port}

Local port number.

If the connection is authenticated, the program should print the user name, followed by a newline character, on its standard output and exit with code ‘0’.

Otherwise, it should exit with a non-zero exit code.

ident[://:port]

The remote machine is asked about the requester identity using the identification protocol (RFC 1413). Both plaintext and DES encrypted replies are understood. Optional port specifies the port to use, if it differs from the default ‘113’. It can be either a decimal port number or a symbolic name of a service, listed in /etc/services.

stdio

PREAUTH mode is enabled automatically if imap4d is started from command line in interactive mode (-i command line option). The current login name is used as the user name.

Imap4d Conf: preauth-only bool

If bool is ‘true’, use only preauth mode. If unable to setup it, disconnect immediately.

Imap4d Conf: ident-keyfile file

Set DES keyfile for decoding encrypted ident responses. Used with ‘ident://’ preauth mode.

Imap4d Conf: ident-encrypt-only bool

Use only encrypted IDENT responses.

Imap4d Conf: id-fields list

Set list of fields to return in response to ID command.

Valid field names are:

name

Package name (‘GNU Mailutils’).

version

Package version (‘3.5’).

vendor

Vendor name (‘GNU’).

support-url

The string ‘http://www.gnu.org/software/mailutils

address

The string ‘51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA’.

os

OS name.

os-version

OS version number.

command

Name of the imap4d binary.

arguments

Invocation command line.

environment

List of environment variables with their values.

3.14.3 Starting imap4d

imap4d may run either in standalone or in inetd operation modes. When run in “standalone” mode, the server disconnects from the terminal and runs as a daemon, forking a child for each new connection.

The “inetd” mode allows to start the server from /etc/inetd.conf file. This is the default operation mode.

imap4  stream tcp nowait  root  /usr/local/sbin/imap4d imap4d

Command Line Options

-d[number]
--daemon[=number]

Run in standalone mode. An optional number specifies the maximum number of child processes the daemon is allowed to fork. When it is omitted, it defaults to 20 processes. Please note, that there should be no whitespace between the -d and its parameter.

-i
--inetd

Run in inetd mode.

--foreground

Run in foreground.

--preauth

Start in preauth mode

--test

Run in test mode.

See also Common Options.

3.15 Comsat Daemon

Comsatd is the server which receives reports of incoming mail and notifies users, wishing to get this service. It can be started either from inetd.conf or as a standalone daemon.

3.15.1 Starting comsatd

-d
--daemon

Run as a standalone daemon.

-i
--inetd

The server is started from /etc/inetd.conf file:

comsat dgram  udp wait  root  /usr/sbin/comsatd \
comsatd -c /etc/comsat.conf

This is the default operation mode.

-t
--test

Test mode. In this mode, comsatd takes two arguments: URL of a mailbox and QID of the message from that mailbox, e.g.:

$ comsatd --test /var/mail/root 34589
--foreground

Don’t detach from the controlling terminal, remain in foreground.

See also Common Options.

3.15.2 Configuring comsatd

Following configuration statements affect the behavior of comsatd:

StatementReference
debugSee debug statement.
loggingSee logging statement.
mailboxSee mailbox statement.
lockingSee locking statement.
aclSee acl statement.

3.15.2.1 General Settings

These statements control the general behavior of the comsat daemon:

Comsatd Conf: max-lines number

Set maximum number of message body lines to be output.

Comsatd Conf: allow-biffrc bool

Enable or disable processing of user’s .biffrc file. By default, it is enabled.

3.15.2.2 Security Settings

These statements control the way comsatd fights possible flooding attacks.

Comsatd Conf: max-requests number

Set maximum number of incoming requests per ‘request-control-interval’.

Comsatd Conf: request-control-interval duration

Set the request control interval.

Comsatd Conf: overflow-delay-time duration

Set initial amount of time to sleep, after the first overflow occurs.

Comsatd Conf: overflow-control-interval duration

Set overflow control interval. If two consecutive overflows happen within that interval, the overflow-delay-time is doubled.

3.15.3 A per-user Configuration File

By default, when a notification arrives, comsatd prints subject, from headers and the first five lines from the new message to the user’s tty. The user is allowed to change this behavior by using his own configuration file. This file should be located in the user’s home directory and should be named .biffrc. It must be owned by the user and have its permissions bits set to 0600. (Please note, that the use of per-user configuration files may be disabled, by specifying ‘allow-biffrc no’ in the main configuration file, see see Configuring comsatd).

The .biffrc file consists of a series of statements. Each statement occupies one line and defines an action to be taken upon arrival of a new mail. Very long lines may be split using ‘\’ as the last character on the line. As usual, comments may be introduced with ‘#’ character.

The actions specified in .biffrc file are executed in turn. The following actions are defined:

beep

Produce an audible signal.

echo [-n] string [string...]

Output the arguments to the user’s terminal device. If several arguments are given they will be output separated by single spaces. The newline character will be printed at the end of the output, unless the -n option is used.

exec prog arglist

Execute program prog with arguments from arglist. prog must be specified with absolute pathname. It may not be a setuid or setgid program.

In the description above, string denotes any sequence of characters. This sequence must be enclosed in a pair of double-quotes, if it contains whitespace characters. The ‘\’ character inside a string starts a C escape sequence. Following meta-characters may be used in strings:

$u

Expands to username

$h

Expands to hostname

$H{name}

Expands to value of message header ‘name’.

$B(c,l)

Expands to message body. c and l give maximum number of characters and lines in the expansion. When omitted, they default to 400, 5.

Example I

Dump to the user’s terminal the contents of ‘From’ and ‘Subject’ headers followed by at most 5 lines of message body.

echo "Mail to \a$u@$h\a\n---\n\
From: $H{from}\n\
Subject: $H{Subject}\n\
---\n\
$B(,5)\
---\n"

The above example can also be written as:

echo Mail to \a$u@$h\a
echo ---
echo From: $H{From}
echo Subject: $H{Subject}
echo ---
echo $B(,5)
echo ---

Example II

Produce a bell, then pop up the xmessage window on display :0.0 with the text formatted in the same manner as in the previous example.

beep
exec /usr/X11R6/bin/xmessage \
-display :0.0 -timeout 10 "Mail to $u@$h \n---\n\
From: $H{from}\n\
Subject: $H{Subject}\n\
---\n\
$B(,5)\
---\n"

3.16 MH — The MH Message Handling System

The primary aim of this implementation is to provide an interface between Mailutils and Emacs using mh-e module.

To use Mailutils MH with Emacs, add the following line to your site-start.el or .emacs file:

(load "mailutils-mh")

For the information about the current state of Mailutils MH implementation please refer to file mh/TODO in the Mailutils distribution directory.

3.16.1 Major differences between Mailutils MH and other MH implementations

  1. UUCP addresses are not supported;
  2. Mailutils supports a set of new format specifications (see Format String Diffs);
  3. Mailutils provides a set of new profile variables (see Profile Variable Diffs);
  4. All programs recognize --help and --version options

    These options are recognized only if no other arguments are present in the command line. Abbreviations are not recognized. This makes Mailutils MH implementation compatible with the standard usage for GNU tools.

  5. Several programs behave differently (see Program Diffs);

3.16.1.1 New and Differing MH Format Specifications

MH Format: string decode (string str)

Decodes the input string str as per RFC 2047. Useful in printing ‘From:’, ‘To:’ and ‘Subject:’ headers.

Notice that, unlike the similar NMH function, decode checks the value of the global profile variable Charset (see Charset variable) to determine the charset to output the result in. If this variable is not set, decode returns its argument without any change. If this variable is set to auto, decode tries to determine the charset name from the setting of LC_ALL environment variable. Otherwise, the value of Charset is taken to be the name of the character set.

MH Format: string package ()

Returns package name (string ‘mailutils’).

MH Format: string package_string ()

Returns full package string (e.g. ‘GNU Mailutils 2.1’)

MH Format: string version ()

Returns mailutils version.

MH Format: string unre (string str)

The function removes any leading whitespace and eventual ‘Re:’ prefix from its argument. Useful for creating subjects in reply messages:

  %<{subject}Subject: Re: %(unre{subject})\\n%>
MH Format: void reply_regex (string r)

Sets the regular expression used to recognize reply messages. The argument r should be a POSIX extended regular expression. Matching is case insensitive.

For example, the following invocation

  %(reply_regex ^\(re|aw|ang|odp\)\(\\[[0-9]+\\]\)?:[[:blank:]])

corresponds to English ‘Re’, Polish ‘Odp’, Norwegian ‘Aw’ or German ‘Ang’, optionally followed by a number in brackets, followed by colon and any amount of whitespace. Notice proper quoting of the regex metacharacters.

See also Reply-Regex (see Reply-Regex variable) and isreply (see isreply MH function) below.

MH Format: boolean isreply ([string str])

If str is not given, the value of ‘Subject:’ header is taken.

The function returns true if its argument matches the “reply subject” regular expression. This expression is set via the global profile variable Reply-Regex (see Reply-Regex variable) or via the format function reply_regex.

This function is useful for creating ‘Subject:’ headers in reply messages. For example, consider the following construction:

%<{subject}%(lit)%<(isreply)%?\
(profile reply-prefix)%(concat)%|%(concat Re:)%>\
%(concat{subject})%(printhdr Subject: )\n%>

If the ‘Subject:’ header already contained reply prefix, this construct leaves it unchanged. Otherwise it prepends to it the value of Reply-Prefix profile variable, or, if it is unset, the string ‘Re:’.

This expression is used in default replcomps and replgroupcomps files.

MH Format: boolean rcpt (‘to’ | ‘cc’ | ‘me’ | ‘all’)

This function returns true if the given element is present in the recipient mask (as modified by -cc or -nocc options) and false otherwise. It is used in default formats for repl and comp, e.g.:

%(lit)%<(rcpt to)%(formataddr{to})%>

Notice that this means that usual replcomps file will be ignoring -cc and -nocc options, unless it has been modified as shown above.

MH Format: string concat ()

Appends whitespace + arg to string register.

MH Format: string printhdr (string str)

Prints the value of string register, prefixed by str. The output is formatted as a RFC 822 header, i.e. it is split at whitespace characters nearest to the width boundary and each subsequent segment is prefixed with horizontal tabulation.

MH Format: string in_reply_to ()

Generates the value for ‘In-reply-to:’ header according to RFC 2822.

MH Format: string references ()

Generates the value for ‘References:’ header according to RFC 2822.

3.16.1.2 New MH Profile Variables

Variable: MH Variable string Charset

Controls the character set in which the components decoded via the decode (see decode function) format function should be output.

Variable: MH Variable string Reply-Regex

Keeps the regular expression used to recognize reply messages. The argument should be a POSIX extended regular expression. Matching is case insensitive.

For more information, please see See reply_regex function.

3.16.1.3 Differences in MH Program Behavior

anno

The prompt in interactive mode is ‘Component name:’, instead of ‘Enter component name:’ displayed by the RAND anno.

If a -component field is not specified and standard input is not connected to a terminal, anno does not display the prompt before reading the component from the standard input. RAND anno displays the prompt anyway.

burst

The utility is able to burst both RFC 934 digest messages and MIME multipart messages. It provides two additional command line options: -recurse and -length.

The -recurse option instructs the utility to recursively expand the digest.

The -length option can be used to set the minimal encapsulation boundary length for RFC 934 digests. Default length is 1, i.e. encountering one dash immediately following a newline triggers digest decoding. It is OK for messages that follow RFC 934 specification. However, many user agents do not precisely follow it, in particular, they often do not escape lines starting with a dash by ‘- ’ sequence. Mailman is one of such agents. To cope with such digests you can set encapsulation boundary length to a higher value. For example, bounce -length 8 has been found to be sufficient for most Mailman-generated digests.

comp

Understands -build option.

fmtdump

This command is not provided. Use fmtcheck instead.

inc
mhl

The ‘ignores’ keyword can be used in variable list. In that case, if its value contains more than one component name it must be enclosed in double-quotes, e.g.:

leftadjust,compwidth=9,"ignores=msgid,message-id,received"

The above is equivalent to the following traditional notation:

leftadjust,compwidth=9
ignores=msgid,message-id,received

The ‘MessageName’ component is not yet implemented.

Interactive prompting is not yet implemented.

The following format variables are silently ignored: ‘center’, ‘split’, ‘datefield’.

mhn
mhparam

The -all mode does not display commented out entries.

pick

New command line option -cflags allows to control the type of regular expressions used. The option must occur right before --component pattern or equivalent construct (like -cc, -from, etc.)

The argument to this option is a string of type specifications:

BUse basic regular expressions
EUse extended regular expressions
IIgnore case
CCase sensitive

Default is ‘EI’.

The flags remain in effect until the next occurrence of -cflags option.

Sample usage:

pick -cflag BC -subject '*a string' 

The date comparison options (-before and -after accept date specifications in a wide variety of formats, e.g.:

pick -after 20030301
pick -after 2003-03-01
pick -after 01-mar-2003
pick -after 2003-mar-01
pick -before '1 year ago'
etc...
prompter
  1. Prompter attempts to use GNU Readline library, if it is installed. Consequently, arguments to -erase and -kill option must follow GNU style key sequence notation (see keyseq in GNU Readline Library).

    If prompter is built without readline, it accepts the following character notations:

    \nnnn

    Here, n stands for a single octal digit.

    ^chr

    This notation is translated to the ASCII code ‘chr + 0100’.

  2. Component continuation lines are not required to begin with a whitespace. If leading whitespace is not present, prompter will add it automatically.
refile
  1. Linking messages between folders goes against the logic of Mailutils, so refile never makes links even if called with -link option. The latter is actually a synonym for -copy, which preserves the original message.
  2. The -preserve option is not implemented. It is retained for backward compatibility only.
  3. Message specs and folder names may be interspersed.
repl

Understands -use option. Disposition shell provides use command.

rmm
  1. Different behaviour if one of the messages in the list does not exist:

    Mailutils rmm does not delete any messages. Standard rmm in this case deletes all messages preceding the non-existent one.

  2. The rmm utility will unlink messages, if the rmmproc profile component has empty value, e.g.:
    rmmproc:
    
sortm

New option -numfield specifies numeric comparison for the given field.

Any number of -datefield, -textfield and -numfield options may be given, thus allowing to build sort criteria of arbitrary complexity.

The order of -.*field options sets the ordering priority. This differs from the behaviour of the standard sortm, which always orders datefield-major, textfield-minor.

Apart from sorting the mailfolder the following actions may be specified:

-list

List the ordered messages using a format string given by -form or -format option.

-dry-run

Do not actually sort messages, rather print what would have been done. This is useful for debugging purposes.

3.17 mailutils

The mailutils utility is a multi-purpose tool shipped with Mailutils. It can be used for various mail and database-related tasks, as well as an auxiliary tool for compiling and linking programs with Mailutils.

3.17.1 Invocation Syntax

Mailutils is a command line tool. Its invocation syntax is:

mailutils [options] command [args]

where options are options that affect the behavior of mailutils as a whole, command instructs it what it is to do and args are any arguments the command needs in order to be executed.

The commands are:

2047

Decodes or encodes email message headers.

acl

Tests Mailutils access control lists.

cflags

Shows compiler options needed to compile with Mailutils.

dbm

Invokes a DBM management tool.

;filter

Applies a chain of filters to the input.

help

Displays a terse help summary.

imap

Invokes an IMAP4 client shell (in development).

info

Displays information about Mailutils compile-time configuration.

ldflags

Constructs a ld(1) command line for linking a program with Mailutils.

logger

Logs information using Mailutils log facility.

pop

Invokes a POP3 client shell.

query

Queries configuration values.

wicket

Scans wicket for matching URLs

3.17.2 mailutils help

The mailutils help command lists all available options and command names along with short descriptions of what each of them does. It is similar to the mailutils --help option.

A command name can be supplied as an argument to help, in which case it will display a help page for that particular command, e.g.:

mailutils help ldflags

will output help for the ldflags command. It is synonymous to the --help option used with that particular command, e.g.: mailutils ldflags --help.

3.17.3 mailutils info

The mailutils info command displays information about Mailutils compile-time configuration. In normal form its output lists a single configuration flag per line, e.g.:

$ mailutils info
VERSION=2.99.93
SYSCONFDIR=/etc
MAILSPOOLDIR=/var/mail/
SCHEME=mbox
LOG_FACILITY=mail
IPV6
USE_LIBPAM
HAVE_LIBLTDL
WITH_GDBM
WITH_GNUTLS
WITH_GSASL

A configuration flag can consist either of a single word, indicating that a particular capability has been enabled at compile time, or of a keyword/value pair delimited by an equal sign, which indicates a particular value used by default for that feature. For example, ‘IPV6’ means that Mailutils was compiled with support for IPv6, whereas ‘SYSCONFDIR=/etc’ means that the default place for configuration files is in /etc directory.

Such short output is convenient for using mailutils info in scripts to decide whether it is possible to use a given feature. To assist human users, the --verbose (-v) option is provided. It prints a short description next to each flag:

$ mailutils info --verbose
VERSION=2.99.93           - Version of this package
SYSCONFDIR=/etc           - System configuration directory
MAILSPOOLDIR=/var/mail/   - Default mail spool directory
SCHEME=mbox               - Default mailbox type
LOG_FACILITY=mail         - Default syslog facility
IPV6                      - IPv6 support
USE_LIBPAM                - PAM support
HAVE_LIBLTDL              - a portable `dlopen' wrapper library
WITH_GDBM                 - GNU DBM
WITH_GNUTLS               - TLS support using GNU TLS
WITH_GSASL                - SASL support using GNU SASL

3.17.4 mailutils cflags

The mailutils cflags command shows compiler options needed to compile a C source with Mailutils. It is intended for use in configuration scripts and Makefiles, e.g.:

CFLAGS=-g -O2 `mailutils cflags`

3.17.5 mailutils ldflags

The mailutils ldflags command is a counterpart of cflags which is used for linking. It constructs a ld command line for linking a program with Mailutils.

When used without arguments, it outputs ld arguments which would link only with the core Mailutils library libmailutils, e.g.:

$ mailutils ldflags
-L/usr/local/lib -lmailutils 

This command accepts a number of keywords which allow to select a particular subset of Mailutils libraries to link with. In particular, the argument ‘all’ instructs it to link in all available libraries:

$ mailutils ldflags all
-L/usr/local/lib -lmu_mbox -lmu_mh -lmu_maildir -lmu_imap -lmu_pop \
-lmu_mailer -lmu_compat -lmailutils -lmu_auth -lgsasl -lgnutls -lgcrypt \
-lldap -lgnuradius -lpam -ldl 

Other available keywords are:

mbox

Link in the UNIX mbox format support.

mh

Link in the MH format support.

maildir

Link in the Maildir format support.

imap

Link in the IMAP protocol support.

pop

Link in the POP protocol support.

nntp

Link in the NNTP protocol support.

mailer

Enable support for mailers.

sieve

Link in the support for Sieve mail filtering language.

dbm

Link in the support for DBM databases (libmu_dbm library).

auth

Link in the Mailutils authentication library.

guile

Provide Guile language bindings.

python

Provide Python language bindings.

3.17.6 mailutils stat

The command mailutils stat shows status of a mailbox. The name or URL of the mailbox to operate upon is supplied in the first argument. If not given, the command will display status of the invoking user system mailbox.

$ mailutils stat
type: maildir
path: /var/mail/smith
URL: /var/mail/smith
size: 3498
messages: 24
recent messages: 3
first unseen: 20
uidvalidity: 1338543026
next uid: 87
access: 2016-12-15 09:15:08 +0200

The output format is controlled by the --format (-c) option. Its argument is the desired format string, composed of ordinary characters, which are reporduced on standard output verbatim, backslash sequences, and format specifiers, beginning with ‘%’.

Backslash sequences are interpreted as in C.

A format specifier consists of a leading ‘%’ followed by a letter. Optional ‘:’ may occur between ‘%’ and the letter. Its presense instructs the program to print the description of the corresponding value before the value itself.

The following format sequences are understood:

%f

Name of the mailbox as supplied in the command line. If mailutils stat was used without explicit mailbox argument, ‘%f’ is equivalent to ‘%U’.

%t

Type of the mailbox (‘mbox’, ‘maildir’, etc.). The description string is ‘type’.

%p

Path to the mailbox. In case of remote mailboxes, it is the path part of the mailbox URL. Description string: ‘path’.

%U

URL of the mailbox. Description string: ‘URL’.

%s

Size of the mailbox in octets. Description string: ‘size’.

%c

Number of messages in the mailbox. Description string: ‘messages’.

%r

Number of recent (unread) messages in the mailbox. Description string: ‘recent messages’.

%u

Index of the first unseen message. Description string: ‘first unseen’.

%v

The UIDVALIDITY value. Description string: ‘uidvalidity’.

%n

The UID value which will be assigned to the new message to be incorporated into the mailbox. Description string: ‘next uid’.

%a

Access time of the mailbox, as a number of seconds since the epoch.

%A

Access time of the mailbox in human-readable format.

3.17.7 mailutils query

The mailutils query command queries values from Mailutils configuration files. It takes one or more configuration paths (see Paths) as its arguments. On output, it displays the values it found, each value on a separate line. If the requested value is a block statement it is displayed in full. For example, if main configuration file contained:

logging {
   syslog yes;
   facility mail;
}

Then:

$ mailutils query .logging.syslog
syslog yes;
$ mailutils query .logging.syslog .logging.facility
syslog yes;
facility mail;
$ mailutils query .logging
logging {
  syslog yes;
  facility mail;
};

Several command line options allow to modify output format. The --value option instructs the command to output only values:

$ mailutils query --value .logging.syslog
yes

The --path option instructs it to print full pathnames for each value:

$ mailutils query --path .logging.syslog
logging.syslog: yes

The --program option instructs mailutils to behave as if it was called under another program name. For example, the following command:

$ mailutils query --program=pop3d .server.transcript

will return the value of the ‘.server.transcript’ statement which the pop3d utility would see.

By default, mailutils query operates on the main configuration file. Another configuration file can be supplied using the --file (-f) option:

$ mailutils query --file /usr/local/etc/file.conf .pidfile

3.17.8 mailutils 2047

The mailutils 2047 command is a filter for decoding or encoding email message headers formatted in accordance with RFC 2047 (see http://www.faqs.org/rfcs/rfc2047.html. By default, it operates in encode mode and assumes the ‘iso-8859-1’ encoding. If arguments are supplied in the command line, they are treated as the text to operate upon. Otherwise the command acts as a UNIX filter, reading lines from the standard input and printing results on the standard output.

For example:

$ mailutils 2047 'Keld Jørn Simonsen <keld@dkuug.dk>'
=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>

The decode mode can be requested via the --decode (-d) option:

$ mailutils 2047 --decode '=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= \
 <keld@dkuug.dk>'
Keld Jørn Simonsen <keld@dkuug.dk>

The --charset (-c) option changes the default character set. It is meaningful both in decode and in encode modes. In decode mode it instructs the utility to convert the output to the given character set. In encode mode it indicates the encoding of the input data, which will be reflected in the resulting string:

$ mailutils 2047 --charset=utf-8 'Keld Jørn Simonsen <keld@dkuug.dk>'
=?utf-8?Q?Keld J=C3=B8rn Simonsen <keld@dkuug.dk>?=

The --encoding (-E) option can be used in encode mode to change the output encoding. Valid arguments for this option are: ‘quoted-printable’ (the default) or ‘base64’.

The --newline (-n) option prints an additional newline character after each line of output.

3.17.9 mailutils filter

The mailutils filter command applies a chain of filters to the input. The filters to apply and their arguments are given in the command line. The full invocation syntax is:

 mailutils filter [option] filter-chain

The syntax for filter-chain in Backus-Naur form follows:

<filter-chain> ::= <filter> | <filter-chain> "+" <filter>
<filter> ::= <filter-spec> <ARG>* 
<filter-spec> ::= <WORD> | "~" <WORD>

where <WORD> stands for the filter name and <ARG> represents filter arguments. To obtain a list of known filter names, run:

mailutils filter --list

Filters are applied in the order of their appearance, from left to right and operate in encode mode. The plus sign has the same meaning as pipe in shell. The default mode can be changed using the --decode (-d) and --encode (-e) options. Whatever the default mode is, a ‘~’ character before filter name reverts the mode for that filter alone.

For example, to encode the contents of file file.txt in Base64 run:

mailutils filter base64 < file.txt

To convert it to base64 and use CRLF as line delimiters, run:

mailutils filter base64 + crlf < file.txt

The following command will decode the produced output:

mailutils filter --decode crlf + base64

It can also be written as

mailutils filter ~crlf + ~base64

The following example converts the input from ISO-8859-2 to UTF-8, quotes eventual ‘From’ occurring at the beginning of a line, encodes the result in Base64 and changes line delimiters to CRLF:

mailutils filter iconv iso-8859-2 utf-8 + from + base64 + crlf

This final example removes UNIX-style comments from the input and joins continuation lines:

mailutils filter --decode inline-comment -S '#' + linecon 

Such invocation can be useful in shell scripts to facilitate configuration file processing.

3.17.10 mailutils acl

The mailutils acl command tests Mailutils Access Control Lists. By default it reads ACL from the Mailutils configuration file section ‘acl’. The command takes a list of IP addresses as its arguments, applies the ACL to each of them in turn and prints the result.

To select the ACL to test, two options are provided. The --file (-f) option supplies the name of configuration file to read instead of the default one. The --path (-p option supplies the pathname (see Paths) of the ACL section to use instead of the default ‘.acl’. For example, to test ACL in section ‘server 213.130.1.232’ of file /etc/pop3d.conf use:

mailutils acl --file=/etc/pop3d.conf \
       --path=/server="213.130.1.232"/acl address

As an example of its use, consider file test.conf with the following contents:

acl {
        deny from 10.10.10.1;
        deny from 10.10.1.0/24;
        log from any "Connect from ${address}";
        allow from 10.0.0.0/8;
        allow from 192.168.1.0/24;
        deny from any;
}

Then, running mailutils acl --file=test.conf 127.0.0.1 you will get:

Testing 127.0.0.1:
mailutils: Connect from 127.0.0.1
127.0.0.1: deny

More examples:

$ mailutils acl --file=test.conf 127.0.0.1 10.10.10.1 \
         10.10.1.3 10.5.3.1 192.168.1.0 192.168.2.0
Testing 127.0.0.1:
mailutils: Connect from 127.0.0.1
127.0.0.1: deny
Testing 10.10.10.1:
10.10.10.1: deny
Testing 10.10.1.3:
10.10.1.3: deny
Testing 10.5.3.1:
mailutils: Connect from 10.5.3.1
10.5.3.1: accept
Testing 192.168.1.0:
mailutils: Connect from 192.168.1.0
192.168.1.0: accept
Testing 192.168.2.0:
mailutils: Connect from 192.168.2.0
192.168.2.0: accept

The mailutils option --debug-level will give you a deeper insight into the address matching algorithm:

$ mailutils --debug-level=acl.trace9 acl --file test.conf 127.0.0.1
Testing 127.0.0.1:
mailutils: Checking sockaddr 127.0.0.1
mailutils: 1:deny: Does 10.10.10.1/255.255.255.255 match 127.0.0.1? no; 
mailutils: 2:deny: Does 10.10.1.0/255.255.255.0 match 127.0.0.1? no; 
mailutils: 3:log: Does any match 127.0.0.1? yes; 
mailutils: Expanding "Connect from ${address}";
mailutils: Expansion: "Connect from 127.0.0.1";. 
mailutils: Connect from 127.0.0.1
mailutils: 4:accept: Does 10.0.0.0/255.0.0.0 match 127.0.0.1? no; 
mailutils: 5:accept: Does 192.168.0.0/255.255.0.0 match 127.0.0.1? no; 
mailutils: 6:deny: Does any match 127.0.0.1? yes; 
127.0.0.1: deny

See acl.

3.17.11 mailutils wicket

The mailutils wicket command looks up matching URLs in the Mailutils ticket file (by default, ~/.mu-tickets) and prints them. The URLs to look for are supplied in the command line.

Consider the following ticket file as an example:

smtp://foo:bar@*
smtp://bar:baz@gnu.org
*://baz:qux@*
*://quux:bar@gnu.org

Now, running mailutils wicket smtp://bar@gnu.org will show:

smtp://bar@gnu.org: /home/user/.mailutils-tickets:2

(where user is your login name). This means that this URL matches the line 2 in your .mailutils-tickets file. The wicket command does not show the actual matching line to avoid revealing eventual security-sensitive information. You can instruct it to do so using the --verbose (-v) option:

$ mailutils wicket -v smtp://bar@gnu.org
smtp://bar@gnu.org: /home/user/.mu-tickets:2: smtp://bar:***@gnu.org

As you see, even in that case the tool hides the actual password part by replacing it with three asterisks. If you are working in a secure environment, you can tell mu wicket to show passwords as well, by supplying the -v option twice.

A counterpart of --verbose is the --quite (-q) option, which instructs wicket to suppress any output, excepting error messages. This can be used in scripts, which analyze the mailutils wicket exit code to alter the control flow.

The mailutils wicket tool exits with code 0 if all URLs were matched and with code 1 if some of them were not matched in the ticket file. If an error occurred, the code 2 is returned.

3.17.12 mailutils dbm

The mailutils dbm tool manages DBM files using libmu_dbm The invocation syntax is:

mailutils dbm subcommand [options] file [keys]

or

mailutils dbm [options] subcommand file [keys]

where subcommand selects the operation mode, options modify the tool behavior and file specifies the DBM file to operate upon. Some commands allow for optional keys to be specified.

The file argument can be either a DBM file name or a Database URL.

3.17.12.1 Create a Database

The create subcommand and its synonym load instruct the tool to create a new database:

mailutils dbm create file.db

If the argument file already exists, it will be truncated prior to adding new records to it.

The data to populate the database with are read from the standard input. The mailutils dbm command supports several formats for these data, which are discussed later. In the simplest case (a so called ‘format 0.0’) each input line must consist of two fields separated by any amount of whitespace. The first field is treated as a key and the second one as the corresponding value.

The usual way to read data from a file is, of course, by redirecting the file to the standard input as in:

mailutils dbm create file.db < input.txt

There is also a special option for that purpose: --file (-f). Thus, the following command is equivalent to the one above:

mailutils dbm create --file input.txt file.db 

The --file option has the advantage that it allows, in conjunction with another options, for copying input file metadata (owner UID, GID and file mode) to the created database. For example, the following command ensures that the created database file will have the same metadata as the input file:

mailutils dbm create --file input.txt --copy-permissions file.db

The --copy-permissions (-P) option is the one that does the job.

There are also other ways to control mode and ownership of the created database, which are described below.

More advanced dump formats (e.g. ‘version 1.0’ format) carry additional information about the file, including its original name, ownership and mode. If input is in one of these formats, the file name argument becomes optional. If it is not supplied, the name stored in the input stream will be used. For example, supposing that the file users.dump is in format 1.0, the following command suffices to restore the original filename, ownership, mode and, of course, data:

mailutils dbm create --file users.dump

3.17.12.2 Add Records to a Database

The add subcommand adds records to a database. Records are read from the standard input and must be formatted as for create:

mailutils dbm add file.db

If the argument file does not exist, it will be created.

Adding a record with a key which is already present in the database produces an error. To replace existing records, use the replace subcommand instead.

The same options that affect the behavior of create apply to add and ‘replace’ as well, e.g.:

mailutils dbm replace --file input.txt --copy-permissions file.db

3.17.12.3 Delete Records

To delete records, use the delete subcommand. It reads a list of keys to delete to be specified as arguments in the command line:

mailutils dbm delete file.db foo bar

The command above will delete from file.db records with keys ‘foo’ and ‘bar’.

It is not an error to attempt to delete a key that does not exist in the database, although such use will produce a warning message.

By default, keys are matched literally. It is also possible to use various pattern matching techniques, depending on the option specified.

The --glob (-G) option instructs the tool to use UNIX globbing pattern matching. For example, the command below will delete all keys starting with ‘foo’ and ending with a decimal digit:

mailutils dbm delete file.db 'foo*[0-9]'

(note the quoting necessary to prevent shell from interpreting the metacharacters itself).

Another option, --regex (-R) instructs mailutils to treat supplied keys as extended regular expressions:

mailutils dbm delete --regex file.db 'foo.*[0-9]{1,3}'

Both options are affected by the --ignore-case (-i) option, which turns on case-insensitive matching.

Using pattern matching to delete records can be a risky operation as selecting a wrong pattern will lead to removing wrong records. It is recommended to first use the list mode described below to verify that the patterns match the right keys.

3.17.12.4 List the Database

The list command lists the content of the database:

mailutils dbm list file.db

By default, entire content is listed on the standard output.

If supplied more than one command line argument, this mode treats the rest of arguments after the database file name as the keys to look for and lists only records with these keys:

$ mailutils dbm list file.db foo bar
foo 1
bar 56

The --glob and --regex options instruct the tool to use UNIX globbing or extended regular expression matching, correspondingly. These were described in detail above.

3.17.12.5 Dump the Database

The dump subcommand dumps the database to the standard output in a format suitable for backup or sending over the network (a version 1.0 format).

mailutils dbm dump file.db < file.dump

The produced file is suitable for input to the create (load) command. Among other uses, it provides an easy way to convert databases between various formats supported by Mailutils. For example this is how to convert the database file file.db to the GDBM database new.db:

mailutils dbm dump file.db | mailutils dbm create gdbm://new.db

Both list and dump subcommands share the same set of options. In fact, they are pretty similar, except that use different defaults. The list subcommand is designed to produce a human-readable output, whereas the dump subcommand is oriented towards backup purposes.

3.17.12.6 Dump Formats

As of version 3.5, mailutils dbm supports two formats for dumping DBM databases. Both formats are line-oriented. Comments are introduced with a sharp (‘#’) sign in the column 0 of a line, followed by at least one white space character (space or tab). Sharp sign followed by a colon (‘#:’) introduces a pragmatic comment, which carries some additional information to the loader.

The version 0.0 format is suitable for databases whose records contain only ASCII data. In this format, each record occupies a separate line, which consists of the key and value separated by a single TAB character. Empty lines are ignored. For example:

$ mailutils list /etc/mail/users.db
root    guessme
smith   pAssword
qed     fooBar

The output in version 0.0 format is human readable and can be used as input to the popauth utility (see popauth. However, version 0.0 has serious drawbacks. First of all, it is not suitable for databases that contain binary data. Secondly, it cannot properly handle keys beginning with a sharp sign or containing TAB. The version 1.0 format is free from these drawbacks.

The version 1.0 dump format begins with a header containing important information about the file, such as its file name, ownership and file mode. This information is stored in pragmatic comments and allows mailutils dbm load to easily recreate an exact copy of the file. The following comments are defined:

#:version=1.0

Indicates that the data that follow are in version 1.0 format.

#:filename=s

Original database file name, without directory parts.

#:uid=n

Owner UID.

#:user=s

Owner name.

#:gid=n

Owner GID

#:group=s

Owner group name.

#:mode=o

File mode in octal

Following this header are actual data. Each record is output in two parts: key and value. Each part begins with a ‘#:len=n’ construct on a line by itself, where n is the length of the data in decimal. This line is followed by one or more lines of the actual data, encoded in base64. The data are formatted so that each line does not exceed 76 bytes in length (not counting the terminating newline). An example of this format follows:

# Database dump file created by GNU Mailutils 2.99.93 on
# Tue Nov  1 13:28:03 2011
#:version=1.0
#:file=users.db
#:uid=0,user=root,gid=25,group=mail,mode=640
#:len=6
c21pdGgA
#:len=9
cEFzc3dvcmQA
#:len=5
cm9vdAA=
#:len=8
Z3Vlc3NtZQA=
#:len=4
cWVkAA==
#:len=7
Zm9vQmFyAA==

3.17.12.7 Dbm Exit Codes

The table below summarizes exit codes used by mailutils dbm:

CodeSymbolic nameMeaning
0EX_OKSuccessful termination
64EX_USAGECommand line usage error
65EX_DATAERRError in user-supplied data: the input file is badly formatted, or some of the data supplied in the command line are invalid (e.g. user name, uid or the like), etc.
66EX_NOINPUTCannot open input file
67EX_NOUSERNo such user or UID when trying to set output file ownership
69EX_UNAVAILABLEOperation cannot be performed due to some kind of problem (e.g. access to the file denied, etc.)
70EX_SOFTWAREInternal software error
74EX_IOERRInput/output error

3.17.13 mailutils logger

The mailutils logger tool logs information using Mailutils log facility.

Syntax:

mailutils logger [options] [message]

The message argument, if supplied, gives the text to log. If not supplied, the utility reads lines of text from standard input or a file (if the --file option is given) and sends them to log:

# Send text to log
$ mailutils logger I am here
# Log each line from file.txt
$ mailutils logger --file file.txt
# Read stdin and log it:
$ mailutils logger

The default logging channel is bound to standard error. To bind it to syslog, use the --syslog command line option. In that case mailutils uses facility ‘user’ and priority ‘err’. You can change this by using the --priority (-p) option. Its argument is either a syslog facility name or facility and severity names separated by a dot. For example, the following invocation will use facility ‘auth’, severity ‘info’:

mailutils logger --priority auth.info

The syslog tag can be set using the --tag (-t) option:

mailutils logger --tag myprog

The default tag is ‘mu-logger’.

The --severity (-s) option sets the Mailutils severity level. Its argument can be any of the following: ‘debug’, ‘info’, ‘notice’, ‘warning’, ‘error’, ‘crit’, ‘alert’, ‘emerg’.

Finally, the --locus (-l) option binds log messages to a location in a file. Its argument has the following syntax:

file:line[:col]

where file is the file name, line is the line number and optional col is the column number in that file.

For example, the following invocation:

mailutils logger --locus mailutils.conf:34 Suspicious statement

will send the following to the log:

mu-logger: mailutils.conf:34: Suspicious statement

3.17.14 mailutils pop

The mailutils pop command invokes an interactive POP3 client shell. It reads commands from the standard input, executes them and displays the results on the standard output. If the standard input is connected to a terminal, the readline and history facilities are enabled (provided that Mailutils is configured with GNU Readline).

The mailutils pop commands form two major groups. POP3 protocol commands interact with the remote POP3 server and display responses obtained from it. These commands are named after their POP3 equivalents. Another group, internal commands, are used to configure the shell itself.

POP protocol commands

connect [-tls] hostname [port]

Open connection to hostname. If the -tls option is given, TLS encryption (also known as POPS protocol) will be used. If port argument is not given, the command uses port 110 for a plain POP connection or 995 for POPS (if -tls is given).

stls

Start TLS negotiation. This command is valid only after successful unencrypted connection has been initiated (using connect without -tls argument).

user name

Send user name to the server. The pass command must follow.

pass [password]

Send password. This command is valid only after user. If the password argument is omitted, the shell will ask you to enter it. While entering, both echoing and history recording will be disabled. Use this to avoid compromising your password.

apop user [password]

Authenticate with APOP. If the password argument is omitted, you will be asked to supply it. While entering, both echoing and history recording will be disabled.

capa [-reread] [name...]

List server capabilities. Any number of arguments is accepted. If given, the shell will display only the named capabilities, otherwise it displays entire list. By default capa reuses the response of its previous invocation (if there was any), instead of resending the ‘CAPA’ command to the server. To force it do so, use the -reread option.

noop

Send a ‘NOOP’ (no operation) command to the server.

stat

Get the mailbox size and number of messages in it.

uidl [number]

Shows unique message identifiers. Without arguments, shows identifiers for each message in the mailbox. If number is given, the command returns the UIDL of that particular message only.

list [number]

Lists messages. See above for the meaning of number. Each line of the produced listing contains describes a single message and contains at least the message number and size in bytes. Depending on the POP3 server implementation, additional fields may be present. For example, Mailutils pop3d can also output number of lines in the message in the additional third field.

retr number

Retrieve a message.

top msgno [number]

Display message headers and first number (default 5) of lines of its body.

dele number

Mark message for deletion.

rset

Remove deletion marks.

quit

Quit pop3 session.

disconnect

Close existing connection.

Internal commands

verbose [on|off|mask|unmask] [secure [payload]]

Control output verbosity. Without arguments the verbose command shows current settings.

The argument ‘off’ (the default) turns off all additional output. The ‘verbose on’ command enables POP3 protocol tracing output. Additional arguments can be used to provide more verbosity. The ‘secure’ argument enables display of user passwords in the trace output and the ‘payload’ argument enables showing payload data (e.g. response body sent in the reply to ‘RETR’ command, etc.) Thus, the full diagnostics output is obtained by

verbose on secure payload

The ‘mask’ and ‘unmask’ arguments allow to disable and enable such additional verbosity. For example, supposing the command above is in action, the following command will suppress the display of user passwords in the traces:

verbose mask secure

Similarly, verbose unmask secure will turn it back again.

prompt string

Set command prompt. The argument can contain variable references in any of the following forms:

$name
${name}

where name is the variable name. Such references are expanded to the actual value of the variable at the time of expansion. The following variables are defined:

VariableExpansion
userLogin name of the authenticated POP3 user. If the session is not authenticated yet, expands to ‘[nouser]’.
hostName of the remote host, or ‘[nohost]’ if no connection is established.
program-nameName of the program, as typed on the command line to invoke it.
canonical-program-namemailutils
packageMailutils
versionMailutils version number (3.5)
statusSession status. One of: ‘disconnected’, ‘connected’ or ‘logged in’.

For example:

prompt "[${user}@$host "

Notice the use of quotes to include the space character in the prompt.

exit

Exit the program.

help [command]
? [command]

Without arguments displays a list of commands with possible arguments and short descriptions.

With one argument, displays a terse description for the given command.

history

Shows command history.

3.17.15 mailutils imap

The mailutils imap command invokes an interactive IMAP4 client shell. It reads commands from the standard input, executes them and displays the results on the standard output. The shell is similar to the mailutils pop (see mailutils pop) shell.

IMAP protocol commands

Most commands in this group correspond (with minor differences) to IMAP commands described in RFC 35014.

imap command: connect [-tls] host [port]

Opens connection to the server host. If the -tls option is given, TLS encryption (also known as IMAPS protocol) will be used. If port argument is not supplied, the command uses port 143 for a plain IMAP connection or 993 for IMAPS (if -tls is given).

imap command: capability [-reread] [name...]

Lists server capabilities. Any number of names is accepted. If at least one is given, the shell will display only the named capabilities, otherwise it displays the entire list. By default, capability reuses the response of its previous invocation (if there was any), instead of resending the CAPABILITY command to the server. To force it do so, use the -reread option.

imap command: starttls

Starts TLS negotiation. This command is valid only after unencrypted connection has been successfully initiated using connect without the -tls option.

imap command: login user [password]

Logs in to the server as user with optional password. If the pass argument is omitted, the shell will ask you to enter it. While entering, both echoing and history recording will be disabled. Use this to avoid compromising your password.

imap command: logout
imap command: quit

Quits the imap session.

imap command: id [-test kw] [arg...]

Sends IMAP ID command. See RFC 29715, for a discussion of arguments. By default, this command outputs entire ID list. If, however, the -test option is given, it will check whether the keyword kw is defined and display its value if so.

imap command: check

Requests a server checkpoint.

imap command: select [mbox]

Selects the named mailbox. Without argument, selects ‘INBOX’.

imap command: examine [mbox]

Examines the named mailbox, i.e. selects it in read-only mode. If mbox is not given, ‘INBOX’ is assumed.

imap command: status mbox kw [kw...]

Gets mailbox status. Valid keywords (kw arguments) are: ‘MESSAGES’, ‘RECENT’, ‘UIDNEXT’, ‘UIDVALIDITY’, and ‘UNSEEN’. Keywords are case-insensitive.

imap command: fetch msgset items

Fetches message data. See RFC 3501, section 6.4.56, for a discussion of its arguments.

imap command: store msgset items

Alters mailbox data. See RFC 3501, section 6.4.67, for a discussion of its arguments.

imap command: close

Closes the currently selected mailbox (with expunge).

imap command: unselect

Closes the currently selected mailbox (without expunge).

imap command: delete mbox

Deletes the mailbox mbox.

imap command: rename old-name new-name

Renames existing mailbox old-name to new-name.

imap command: expunge

Permanently removes messages marked for deletion.

imap command: create name

Creates new mailbox with the given name.

imap command: append [-time datetime] [-flag flag] mailbox file

Reads an RFC-822 message from file and appends it to the mailbox. Use the -time option to supply envelope date for the message. Use the -flag option to supply message flags. For example:

append -time "25-Aug-2002 18:00:00 +0200" -flag \Seen INBOX input.msg
imap command: list ref mbox

Lists matching mailboxes. See RFC 3501, section 6.3.88, for a discussion of its arguments.

imap command: lsub ref mbox

Lists subscribed mailboxes (RFC 3501, section 6.3.99).

imap command: subscribe mbox

Subscribes to a mailbox.

imap command: unsubscribe mbox

Removes mailbox mbox from the subscription list.

imap command: noop

Sends a no operation command.

imap command: disconnect

Closes existing connection.

Internal commands

The imap shell implements the same set of internal commands as pop shell: See Internal commands. There is only one imap-specific internal command:

imap command: uid [on|off]

Controls the UID mode. When the UID mode is on, the commands fetch and store operate on and return message UIDs instead of their sequence numbers.

To examine the current state of the UID mode, issue the uid command without arguments.

3.17.16 mailutils send

Reads an RFC-822 message from a file and sends it over to a specified SMTP server. The syntax is:

mailutils send [options] host file

where host defines the SMTP server through which to send the message, and file is the name of the input file containing the message. For example, to send a message from file input.msg using SMTP service at localhost, one would write:

$ mailutils send localhost input.msg

The host argument can be an IP address, hostname, or a valid SMTP URL.

The following command line options are understood:

-F address
--from=address

Supplies envelope sender address.

-T address
--rcpt=address

Supplies envelope recipient address. It can be specified multiple times.

-t
--read-recipients

Instructs the program to read recipient email addresses from the message ‘To:’, ‘Cc:’, and ‘Bcc:’ headers.

3.17.17 mailutils smtp

The mailutils smtp command invokes an interactive SMTP client shell. It reads commands from the standard input, executes them and displays the results on the standard output. If the standard input is connected to a terminal, the readline and history facilities are enabled (provided that Mailutils is configured with GNU Readline).

Initializing connection

smtp command: connect [-tls] host [port]

Connects to SMTP server at host (IP address or host name). If the -tls option is given, TLS encryption (also known as SMTPS protocol) will be used. The default port number is 25 for plain SMTP and 465 for SMTPS. Explicit port argument overrides the default value.

Connection parameters

A number of parameters is associated with an open connection:

domain

Domain name used in EHLO statement. Defaults to the current host name.

The following parameters are used for ESMTP authentication:

username

User name.

password

User password.

service

GSASL service name.

realm

Realm name.

host

Host name.

url

SMTP URL. It can contain all of the above. Default is smtp://

These parameters are manipulated using the following statements:

smtp command: set param value [param value...]

Sets parameter param to value. Several parameters can be set with one set statement.

smtp command: clear [param...]

Unset the supplied connection parameters. If used without arguments, unsets all parameters.

smtp command: list [param...]

Lists the values of the connection parameters. If used without arguments, lists all parameters.

SMTP commands

smtp command: ehlo [domain]

Sends the ESMTP greeting. Unless domain is supplied, the connection parameter ‘domain’ is used.

smtp command: capa [name...]

Lists the server capabilities.

smtp command: starttls

Initiates encrypted connection. This command is disabled if the connection is opened with the -tls option.

smtp command: auth mech [mech...]

Authenticate using the supplied mechanisms.

smtp command: rset

Reset the session state.

smtp command: from [email]

Sets sender email address. If used without arguments, prints the sender email address.

smtp command: to [email]

Sets recipient email address. If used without arguments, prints all recepient names collected so far.

smtp command: smtp command [args...]

Sends the command with its arguments verbatim.

smtp command: quit

Quits the SMTP session.

smtp command: send [file]

Reads the message from file and sends it. If file is not supplied, the action depends on whether a send command was used prevously within the same session. If so, mailutils will first ask whether to reuse the already supplied message. If not, it will start an editor, allowing you to enter the new message. When you exit from the editor, you will be prompted what to do with the message: send, edit, or quit (discard) it.

Internal commands

Internal commands are the same as in pop shell: See Internal commands.

Footnotes

(1)

For backward compatibility, map can be a string containing colon-delimited list of mappings. Such usage is, however, deprecated.

(2)

Rmail does not use this feature

(3)

The exact location is determined at configuration time by setting environment variable DEFAULT_CUPS_CONFDIR. On most sites running

./configure DEFAULT_CUPS_CONFDIR=/etc/cups

should be recommended.

(4)

See http://www.faqs.org/rfcs/rfc3501.html.

(5)

http://www.faqs.org/rfcs/rfc2971.html

(6)

http://tools.ietf.org/html/rfc3501#section-6.4.5

(7)

http://tools.ietf.org/html/rfc3501#section-6.4.6

(8)

http://tools.ietf.org/html/rfc3501#section-6.3.8

(9)

http://tools.ietf.org/html/rfc3501#section-6.3.9

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