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FORMAIL(1)
NAME
formail - mail (re)formatter
SYNOPSIS
formail [+skip] [-total] [-bczfrktedqBY] [-p prefix]
[-D maxlen idcache]
[-l folder]
[-x headerfield] [-X headerfield]
[-a headerfield] [-A headerfield]
[-i headerfield] [-I headerfield]
[-u headerfield] [-U headerfield]
[-R oldfield newfield]
[-n [maxprocs ]] [-m minfields] [-s [command [arg ...]]]
formail -v
DESCRIPTION
formail is a filter that can be used to force mail into mailbox format,
perform `From ' escaping, generate auto-replying headers, do simple header
munging/extracting or split up a mailbox/digest/articles file. The
mail/mailbox/article contents will be expected on stdin.
If formail is supposed to determine the sender of the mail, but is unable
to find any, it will substitute `foo@bar'.
If formail is started without any command line options, it will force any
mail coming from stdin into mailbox format and will escape all bogus `From
' lines with a `>'.
OPTIONS
-v Formail will print its version number and exit.
-b Don't escape any bogus mailbox headers (i.e., lines starting with
`From ').
-p prefix
Define a different quotation prefix. If unspecified it defaults to
`>'.
-Y Assume traditional Berkeley mailbox format, ignoring any Content-
Length: fields.
-c Concatenate continued fields in the header. Might be convenient when
postprocessing mail with standard (line oriented) text utilities.
-z Ensure a whitespace exists between field name and content. Zap fields
which contain only a single whitespace character. Zap leading and
trailing whitespace on fields extracted with -x.
-f Force formail to simply pass along any non-mailbox format (i.e., don't
generate a `From ' line as the first line).
-r Generate an auto-reply header. This will normally throw away all the
existing fields (except X-Loop:) in the original message, fields you
wish to preserve need to be named using the -i option. If you use
this option in conjunction with -k, you can prevent the body from
being `escaped' by also specifying -b.
-k When generating the auto-reply header or when extracting fields, keep
the body as well.
-t Trust the sender to have used a valid return address in his header.
This causes formail to select the header sender instead of the
envelope sender for the reply. This option should be used when
generating auto-reply headers from news articles or when the sender of
the message is expecting a reply.
-s The input will be split up into separate mail messages, and piped into
a program one by one (a new program is started for every part). -s
has to be the last option specified, the first argument following it
is expected to be the name of a program, any other arguments will be
passed along to it. If you omit the program, then formail will simply
concatenate the split mails on stdout again. See FILENO.
-n [maxprocs]
Tell formail not to wait for every program to finish before starting
the next (causes splits to be processed in parallel). Maxprocs
optionally specifies an upper limit on the number of concurrently
running processes.
-e Do not require empty lines to be preceding the header of a new message
(i.e., the messages could start on every line).
-d Tell formail that the messages it is supposed to split need not be in
strict mailbox format (i.e., allows you to split digests/articles or
non-standard mailbox formats). This disables recognition of the
Content-Length: field.
-l folder
Generate a log summary in the same style as procmail. This includes
the entire "From " line, the Subject: header field, the folder, and
the size of the message in bytes. The mailstat command can be used to
summarize logs in this format.
-B Makes formail assume that it is splitting up a BABYL rmail file.
-m minfields
Allows you to specify the number of consecutive headerfields formail
needs to find before it decides it found the start of a new message,
it defaults to 2.
-q Tells formail to (still detect but) be quiet about write errors,
duplicate messages and mismatched Content-Length: fields. This option
is on by default, to make it display the messages use -q-.
-D maxlen idcache
Formail will detect if the Message-ID of the current message has
already been seen using an idcache file of approximately maxlen size.
If not splitting, it will return success if a duplicate has been
found. If splitting, it will not output duplicate messages. If used
in conjunction with -r, formail will look at the mail address of the
envelope sender instead at the Message-ID.
-x headerfield
Extract the contents of this headerfield from the header. Line
continuations will be left intact; if you want the value on a single
line then you'll also need the -c option.
-X headerfield
Same as -x, but also preserves/includes the field name.
-a headerfield
Append a custom headerfield onto the header; but only if a similar
field does not exist yet. If you specify either one of the field
names Message-ID: or Resent-Message-ID: with no field contents, then
formail will generate a unique message-ID for you.
-A headerfield
Append a custom headerfield onto the header in any case.
-i headerfield
Same as -A, except that any existing similar fields are renamed by
prepending an ``Old-'' prefix. If headerfield consists only of a
field-name, it will not be appended.
-I headerfield
Same as -i, except that any existing similar fields are simply
removed. If headerfield consists only of a field-name, it effectively
deletes the field.
-u headerfield
Make the first occurrence of this field unique, and thus delete all
subsequent occurrences of it.
-U headerfield
Make the last occurrence of this field unique, and thus delete all
preceding occurrences of it.
-R oldfield newfield
Renames all occurrences of the fieldname oldfield into newfield.
+skip
Skip the first skip messages while splitting.
-total
Output at most total messages while splitting.
NOTES
When renaming, removing, or extracting fields, partial fieldnames may be
used to specify all fields that start with the specified value.
By default, when generating an auto-reply header procmail selects the
envelope sender from the input message. This is correct for vacation
messages and other automatic replies regarding the routing or delivery of
the original message. If the sender is expecting a reply or the reply is
being generated in response to the contents of the original message then
the -t option should be used.
RFC822, the original standard governing the format of Internet mail
messages, did not specify whether Resent header fields (those that begin
with `Resent-', such as `Resent-From:') should be considered when
generating a reply. Since then, the recommended usage of the Resent
headers has evolved to consider them as purely informational and not for
use when generating a reply. This has been codified in RFC2822, the new
Internet Message Format standard, which states in part:
Resent fields are used to identify a message as having been
reintroduced into the transport system by a user. The purpose of
using resent fields is to have the message appear to the final
recipient as if it were sent directly by the original sender, with all
of the original fields remaining the same....They MUST NOT be used in
the normal processing of replies or other such automatic actions on
messages.
While formail now ignores Resent headers when generating header replies,
versions of formail prior to 3.14 gave such headers a high precedence. If
the old behavior is needed for established applications it can be specified
by calling formail with the option `-a Resent-' in addition to the -r and
-t options. This usage is deprecated and should not be used in new
applications.
ENVIRONMENT
FILENO
While splitting, formail assigns the message number currently being
output to this variable. By presetting FILENO, you can change the
initial message number being used and the width of the zero-padded
output. If FILENO is unset it will default to 000. If FILENO is
non-empty and does not contain a number, FILENO generation is
disabled.
EXAMPLES
To split up a digest one usually uses:
formail +1 -ds >>the_mailbox_of_your_choice
or
formail +1 -ds procmail
To remove all Received: fields from the header:
formail -I Received:
To remove all fields except From: and Subject: from the header:
formail -k -X From: -X Subject:
To supersede the Reply-To: field in a header you could use:
formail -i "Reply-To: foo@bar"
To convert a non-standard mailbox file into a standard mailbox file you can
use:
formail -ds <old_mailbox >>new_mailbox
Or, if you have a very tolerant mailer:
formail -a Date: -ds <old_mailbox >>new_mailbox
To extract the header from a message:
formail -X ""
or
sed -e '/^$/ q'
To extract the body from a message:
formail -I ""
or
sed -e '1,/^$/ d'
SEE ALSO
mail(1), binmail(1), sendmail(8), procmail(1), sed(1), sh(1), RFC822,
RFC2822, RFC1123
DIAGNOSTICS
Can't fork Too many processes on this machine.
Content-Length: field exceeds actual length by nnn bytes
The Content-Length: field in the header specified a
length that was longer than the actual body. This
causes this message to absorb a number of subsequent
messages following it in the same mailbox.
Couldn't write to stdout
The program that formail was trying to pipe into
didn't accept all the data formail sent to it; this
diagnostic can be suppressed by the -q option.
Duplicate key found: x The Message-ID or sender x in this message was found
in the idcache; this diagnostic can be suppressed by
the -q option.
Failed to execute "x" Program not in path, or not executable.
File table full Too many open files on this machine.
Invalid field-name: "x"
The specified field-name "x" contains control char-
acters, or cannot be a partial field-name for this
option.
WARNINGS
You can save yourself and others a lot of grief if you try to avoid using
this autoreply feature on mails coming through mailinglists. Depending on
the format of the incoming mail (which in turn depends on both the original
sender's mail agent and the mailinglist setup) formail could decide to gen-
erate an autoreply header that replies to the list.
In the tradition of UN*X utilities, formail will do exactly what you ask it
to, even if it results in a non-RFC822 compliant message. In particular,
formail will let you generate header fields whose name ends in a space in-
stead of a colon. While this is correct for the leading `From ' line, that
line is not a header field so much as the message separator for the mbox
mailbox format. Multiple occurrences of such a line or any other colonless
header field will be considered by many mail programs, including formail
itself, as the beginning of a new message. Others will consider the mes-
sage to be corrupt. Because of this, you should not use the -i option with
the `From ' line as the resulting renamed line, `Old-From ', will probably
not do what you want it to. If you want to save the original `From ' line,
rename it with the -R option to a legal header field such as `X-From_:'.
BUGS
When formail has to generate a leading `From ' line it normally will con-
tain the current date. If formail is given the option `-a Date:', it will
use the date from the `Date:' field in the header (if present). However,
since formail copies it verbatim, the format will differ from that expected
by most mail readers.
If formail is instructed to delete or rename the leading `From ' line, it
will not automatically regenerate it as usual. To force formail to regen-
erate it in this case, include -a 'From '.
If formail is not called as the first program in a pipe and it is told to
split up the input in several messages, then formail will not terminate un-
til the program it receives the input from closes its output or terminates
itself.
If formail is instructed to generate an autoreply mail, it will never put
more than one address in the `To:' field.
MISCELLANEOUS
Formail is eight-bit clean.
When formail has to determine the sender's address, every RFC822 conforming
mail address is allowed. Formail will always strip down the address to its
minimal form (deleting excessive comments and whitespace).
The regular expression that is used to find `real' postmarks is:
"\n\nFrom [\t ]*[^\t\n ]+[\t ]+[^\n\t ]"
If a Content-Length: field is found in a header, formail will copy the
number of specified bytes in the body verbatim before resuming the regular
scanning for message boundaries (except when splitting digests or Berkeley
mailbox format is assumed).
Any header lines immediately following the leading `From ' line that start
with `>From ' are considered to be a continuation of the `From ' line. If
instructed to rename the `From ' line, formail will change each leading `>'
into a space, thereby transforming those lines into normal RFC822 continua-
tions.
NOTES
Calling up formail with the -h or -? options will cause it to display a
command-line help page.
SOURCE
This program is part of the procmail mail-processing-package (v3.22) avail-
able at http://www.procmail.org/ or ftp.procmail.org in pub/procmail/.
MAILINGLIST
There exists a mailinglist for questions relating to any program in the
procmail package:
<procmail-users@procmail.org>
for submitting questions/answers.
<procmail-users-request@procmail.org>
for subscription requests.
If you would like to stay informed about new versions and official patches
send a subscription request to
procmail-announce-request@procmail.org
(this is a readonly list).
AUTHORS
Stephen R. van den Berg
<srb@cuci.nl>
Philip A. Guenther
<guenther@sendmail.com>
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Index for
Section 1 |
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Alphabetical
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