FORMAIL linux command manual

FORMAIL(1)                                                         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 for-
       mat, perform 'From ' escaping, generate auto-replying headers, do sim-
       ple  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 util-

       -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  argu-
            ment  following  it  is expected to be the name of a program, any
            other arguments will be passed along to it.  If you omit the pro-
            gram,  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 com-
            mand 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 for-
            mail 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 mes-
            sages.  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 simi-
            lar field does not exist yet.  If you specify either one  of  the
            field  names Message-ID: or Resent-Message-ID: with no field con-
            tents, 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 effec-
            tively 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 the first skip messages while splitting.

            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 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

              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  applica-
       tions  it  can  be  specified  by  calling formail with the option '-a
       Resent-' in addition to the -r and -t options.  This usage  is  depre-
       cated and should not be used in new applications.

            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 gen-
            eration is disabled.

       To split up a digest one usually uses:
              formail +1 -ds >>the_mailbox_of_your_choice
              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 >new_mailbox

       Or, if you have a very tolerant mailer:
              formail -a Date: -ds >new_mailbox

       To extract the header from a message:
              formail -X ""
              sed -e '/^$/ q'

       To extract the body from a message:
              formail -I ""
              sed -e '1,/^$/ d'

       mail(1), binmail(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  speci-
                              fied  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 in-
                              to  didn't  accept all the data formail sent to
                              it; this diagnostic can be suppressed by the -q

       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)  for-
       mail  could decide to generate an autoreply header that replies to the

       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 ter-
       minate 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  con-
       forming  mail  address is allowed.  Formail will always strip down the
       address to its minimal form (deleting excessive comments  and  whites-

       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 (v3.22)
       available at or in pub/proc-

       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
       (this is a readonly list).

       Stephen R. van den Berg
       Philip A. Guenther

BuGless                           2001/08/04                       FORMAIL(1)