Mail Variables (GNU Mailutils Manual)

3.5.7 How to Alter the Behavior of `mail`

Following variables control the behavior of GNU mail:

mail: boolean append

Default: True
Comment: Read-Only

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.

mail: boolean appenddeadletter

Default: False

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

mail: boolean askbcc

Default: False

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

mail: boolean askcc

Default: True

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

mail: boolean asksub

Default: True in interactive mode, False otherwise.

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

mail: boolean autoinc

Default: True

Automatically incorporate newly arrived messages.

mail: boolean autoprint

Default: False

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

mail: boolean bang

Default: False

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

See Executing Shell Commands, for details on the ! escape.

mail: boolean datefield

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.

mail: string charset

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 the ‘charset’ parameter 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.

mail: string cmd

Default: Unset

Contains default shell command for pipe.

mail: numeric columns

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.

mail: numeric crt

mail: boolean crt

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.

mail: boolean debug

mail: string debug

Default: Unset

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.

mail: string decode-fallback

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’.

mail: boolean dot

Default: False

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

mail: boolean editheaders

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.

mail: boolean emptystart

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.

mail: string escape

Default: ‘~’

Current value of the command escape character.

mail: boolean flipr

Default: Unset

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

mail: string folder

Default: Unset

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

mail: boolean fromfield

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.

mail: boolean fullnames

Default: True

Preserve personal parts (comments) of recipient addresses when replying to a message.

When unset, only emails will be used.

See Replying.

mail: boolean header

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

Whether to run headers command automatically after entering interactive mode.

mail: string headline

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:

‘`M`’	the message was copied to the mailbox (`mbox` command)
‘`P`’	the message was preserved (`hold` command)
‘`*`’	the message was saved (`save` or `Save`)
‘`T`’	the message was tagged (`tag`)
‘`R`’	the message was read
‘`N`’	the message is new (was not seen)
‘`U`’	the message was seen, but wasn’t read

%d

The date when the message was received. It is determined from the message header defined 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.

mail: boolean hold

Default: False

Determines the location where to store the messages in state ‘read’ and (if the keepsave is also set) ‘saved’. When set, these messages will be retained in the system mailbox.

When not set (the default), such messages will be stored in the user’s personal mailbox.

See read messages, and See saved messages, for a detailed information on how such messages are processed when the mailbox is being closed.

See keepsave, for the discussion of the keepsave variable.

mail: boolean ignore

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.

mail: boolean ignoreeof

Default: False

Controls whether typing EOF character terminates the letter being composed.

mail: string indentprefix

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

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

mail: boolean inplacealiases

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.

mail: boolean keep

Comment: 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.

mail: boolean keepsave

Default: False

Controls whether saved messages should be retained. The location where they will be retained is controlled by the hold variable (see the hold variable).

This variable is in effect only when operating upon the user’s system mailbox.

See saved messages, for a detailed information on how the saved messages are processed when the mailbox is being closed.

mail: boolean mailx

Default: False

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

When composing a message mail will ask for Cc and Bcc addresses after composing the body. The default behavior is to ask for these values before composing the body.
In send mode, if the composition was interrupted, mail will exit with zero status. By default it exits with zero status only if the message was sent successfully.
The outfolder variable is treated as boolean. see outfolder.
The value of outfilename is ignored (assumed to be ‘local’). see outfilename.
The values of folder and record variables are assumed relative to the home directory, unless they begin with ‘/’, ‘~’, or ‘+’.
If the value of the sendmail variable does not begin with a scheme specification, ‘sendmail:/’ is assumed. See sendmail mail variable.

mail: boolean metamail

mail: string metamail

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"

mail: string mime

Default: False

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

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

mail: string mimenoask

Default: Unset

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’.

mail: boolean metoo

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.

mail: string mode

Comment: 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.

mail: boolean nullbody

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'

mail: string nullbodymsg

Default: ‘Null message body; hope that's ok’

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.

mail: boolean onehop

Default: Unset

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

mail: string outfilename

Comment: Three-state: ‘local’, ‘email’, ‘domain’.
Default: ‘local’

Defines the algorithm to convert the recipient email to the name of the file used to record outgoing messages to that recipient. This affects the following commands: Copy, Save, Mail, followup, and Followup. The following values are allowed:

local: Local part of the email address is taken as the file name. This is the default.
email: Entire email is takes as the file name.
domain: Domain part of the email is used as the file name.

mail: boolean outfolder

mail: string outfolder

Default: Unset

When set as boolean, causes the files used to record outgoing messages to be located in the directory specified by the folder variable (unless the pathname is absolute).

If set to a string value, names the directory where to store these files.

This variable affects the following commands: Copy, Save, Mail, followup, and Followup.

In mailx compatibility mode, only boolean value is allowed. see mailx mail variable.

mail: boolean page

Default: Unset

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

mail: string PID

Comment: Read-Only
Default: PID of the process.

PID of the current mail process.

mail: string prompt

Default: "? "

Contains the command prompt sequence.

mail: boolean quiet

Default: Unset

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

mail: boolean quit

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

When set, causes keyboard interrupts to terminate the program.

mail: boolean rc

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.

mail: boolean readonly

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.

mail: string record

Default: Unset

When set, outgoing messages produced by the following commmands will be saved to the named file: mail, reply, Reply.

GNU Mailutils

General-Purpose Mail Package

3.5.7 How to Alter the Behavior of mail

3.5.7 How to Alter the Behavior of `mail`