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 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 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/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 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 mes-
	    sage, 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 prece-
       dence.  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 op-
			      tion.

       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.  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 lead-
       ing `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:
	      "

From [	 ]*[^	
 ]+[	 ]+[^
	 ]"

       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/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)