formail - mail (re)formatter


SYNOPSIS

       formail [+skip] [-total] [-vbczfrktedqBY] [-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
       ...]]]


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/mail­
       box/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.

            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  mes­
            sages,  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  pro­
            cessed  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.

            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 summa­
            rize 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 head­
            erfields  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 Con­
            tent-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 spec­
            ify either one of  the  field  names  Message-ID:  or
            Resent-Message-ID:  with no field contents, then for­
            mail will generate a unique message-ID for you.

            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  informa­
       tional  and  not for use when normally generating a reply.
       While formail now ignores Resent headers  when  generating

       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 preset­
            ting FILENO, you can change the initial message  num­
            ber  being used and the width of the zero-padded out­
            put.  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'

       mail(1), binmail(1), sendmail(8), procmail(1), sed(1),
       sh(1), RFC822, 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 fol­
                              lowing 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 exe­
                              cutable.

       File table full        Too many open  files  on  this  ma­
                              chine.

       Invalid field-name: "x"
                              The  specified  field-name "x" con­
                              tains 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  in­
       coming  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 exact­
       ly  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 mes­

       currences  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 re­
       ceives the input from closes its output or terminates  it­
       self.

       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  (delet­
       ing excessive comments and whitespace).

       The  regular  expression that is used to find `real' post­
       marks 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 verba­
       tim 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

       to 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-pack­
       age   (v3.21)  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>


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