formail



FORMAIL(1)                                                          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 utili-
            ties.

       -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 start-
            ing  the  next  (causes splits to be processed in parallel).  Max-
            procs optionally specifies an upper limit on the number of concur-
            rently 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/arti-
            cles 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  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 sin-
            gle 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  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
            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 speci-
                              fied a length that was longer  than  the  actual
                              body.  This causes this message to absorb a num-
                              ber 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 op-
                              tion.

       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 us-
       ing  this  autoreply feature on mails coming through mailinglists.  De-
       pending 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
       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 mes-
       sage.   Others  will  consider  the  message to be corrupt.  Because of
       this, you should not use the -i option with the ‘From ’ line as the re-
       sulting  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 termi-
       nate  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 con-
       forming mail address is allowed.  Formail will always  strip  down  the
       address  to  its  minimal form (deleting excessive comments and whites-
       pace).

       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 reg-
       ular 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/proc-
       mail/.


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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