formail



FORMAIL(1)                  General Commands Manual                 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
                              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 (v3.22)
       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:
              <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>

BuGless                           2001/08/04                        FORMAIL(1)

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