FORMAIL(1)                  General Commands Manual                 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  un-
       able 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  bo-
       gus `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 utili-

       -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 in-
            cludes 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  ad-
            dress 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 re-
            moved.   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 re-
       ply is being generated in response to the contents of the original mes-
       sage 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 be-
       gin 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  fi-
              nal  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.

            While  splitting, formail assigns the message number currently be-
            ing 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 genera-
            tion 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 <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 ""
              sed -e '/^$/ q'

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

       mail(1), sendmail(8), procmail(1), sed(1), sh(1), RFC822, RFC2822,

       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-

       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 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

       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_:'.

       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.

       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  white-

       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.

       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)
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