FORMAIL(1) User Commands FORMAIL(1)
formail - mail (re)formatter
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
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 `>'.
-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.
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 formail 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.
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.
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'
mail(1), sendmail(8), procmail(1), sed(1), sh(1), RFC822, RFC2822,
RFC1123
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
characters, or cannot be a partial field-name
for this option.
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 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 compliant message. In
particular, formail will let you generate 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_:'.
When formail has to generate a leading `From ' line it normally 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 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 regenerate 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 until 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.
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 continuations.
Calling up formail with the -h or -? options will cause it to display
a command-line help page.
This program is part of the procmail mail-processing-package (v3.24)
available at http://www.procmail.org/ or ftp.procmail.org in
pub/procmail/.
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).
Stephen R. van den Berg
<srb@cuci.nl>
BuGless 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 formail 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), 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
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 incoming 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 compliant message. In
particular, formail will let you generate 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 normally 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 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 regenerate 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 until 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 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 (v3.24)
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:
<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>
BuGless FORMAIL(1)