User Commands 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.
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User Commands FORMAIL(1)
-z Ensure a whitespace exists between field name and con-
tent. Zap fields which contain only a single whi-
tespace character. Zap leading and trailing whitespace
on fields extracted with -x.
-f Force formail to simply pass along any non-mailbox for-
mat (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 extract-
ing 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).
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User Commands FORMAIL(1)
-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 for-
mats). 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 summar-
ize 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 header-
fields 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.
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-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 header-
field 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 mes-
sage then the -t option should be used.
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User Commands FORMAIL(1)
RFC822, the original standard governing the format of Inter-
net 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 stan-
dard, 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 mes-
sage appear to the final recipient as if it were sent
directly by the original sender, with all of the origi-
nal 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 genera-
tion is disabled.
EXAMPLES
To split up a digest one usually uses:
formail ]1 -ds >>themailboxofyourchoice
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"
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User Commands FORMAIL(1)
To convert a non-standard mailbox file into a standard mail-
box file you can use:
formail -ds >newmailbox
Or, if you have a very tolerant mailer:
formail -a Date: -ds >newmailbox
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 follow-
ing 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 diag-
nostic 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 execut-
able.
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File table full Too many open files on this machine.
Invalid field-name: "x"
The specified field-name "x" contains
control characters, 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 incom-
ing mail (which in turn depends on both the original
sender's mail agent and the mailinglist setup) formail could
decide to generate 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 com-
pliant message. In particular, formail will let you gen-
erate header fields whose name ends in a space instead 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
message 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 nor-
mally will contain 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 expect-
ed 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 regenerate it in this case, in-
clude -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 until the program it receives the
input from closes its output or terminates itself.
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If formail is instructed to generate an autoreply mail, it
will never put more than one address in the `To:' field.
MISCELANEOUS
Formail is eight-bit clean.
When formail has to determine the sender's address, every
RFC822 conforming mail address is allowed. Formail will al-
ways 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 con-
tinuation 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
continuations.
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) available 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:
for submitting questions/answers.
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).
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User Commands FORMAIL(1)
AUTHORS
Stephen R. van den Berg
Philip A. Guenther
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWprocmail
Interface Stability Committed
NOTES
Source for procmail is available on http:/opensolaris.org.
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