NAME

       maildropex - maildrop filtering language examples

SYNOPSIS

       $HOME/.mailfilter, $HOME/.mailfilters/*

DESCRIPTION

       If $HOME/.mailfilter exists, filtering instructions in this file will be carried out prior
       to delivering the message. The filtering instructions may instruct maildrop to discard the
       message, save the message in a different mailbox, or forward the message to another
       address. If $HOME/.mailfilter does not exist, or does not provide explicit delivery
       instructions, maildrop delivers the message to the user's system mailbox.

       The files in $HOME/.mailfilters are used when maildrop is invoked in embedded mode.

EXAMPLES

       Take all mail that's sent to the 'auto' mailing list, and save it in Mail/auto. The 'auto'
       mailing list software adds a "Delivered-To: auto@domain.com" header to all messages:

           if (/^Delivered-To: *auto@domain\.com$/)
               to Mail/auto

       After the to command delivers the message, maildrop automatically stops filtering and
       terminates without executing the subsequent instructions in the filter file.

       Take all mail from <boss@domain.com> about the current project status, save it in
       Mail/project, then forward a copy to John:

           if (/^From: *boss@domain\.com/ \
               && /^Subject:.*[:wbreak:]project status[:wbreak:]/)
           {
               cc "!john"
               to Mail/project
           }

       Note that it is necessary to use a backslash in order to continue the if statement on the
       next line.

       Keep copies of the last 50 messages that you received in the maildir directory 'backup'.
       NOTE: 'backup' must be a maildir directory, not a mailbox. You can create a maildir using
       the maildirmake command.

           cc backup
           `cd backup/new && rm -f dummy \`ls -t | sed -e 1,50d\``

       Put this at the beginning of your filter file, before any other filtering instructions.
       This is a good idea to have when you are learning maildrop. If you make a mistake and
       accidentally delete a message, you can recover it from the backup/new subdirectory.

       Save messages that are at least 100 lines long (approximately) into Mail/IN.Large::

                if ( $LINES > 100 )
                   to Mail/IN.Large

       Send messages from the auto mailing list to the program 'archive', using a lock file to
       make sure that only one instance of the archive program will be running at the same time:

                if (/^Delivered-To: *auto@domain\.com$/)
                   dotlock "auto.lock" {

                          to "|archive"
                   }

       Check if the Message-ID: header in the message is identical to the same header that was
       recently seen. Discard the message if it is, otherwise continue to filter the message:

           `reformail -D 8000 duplicate.cache`
           if ( $RETURNCODE == 0 )
               exit

       The reformail[1] command maintains a list of recently seen Message-IDs in the file
       duplicate.cache.

           Note
           Unlike a similar feature in the formail command, reformail[1] takes care of locking
           the file, so it's not necessary to implement your own locking mechanism for this
           option.

       Here's a more complicated example. This fragment is intended to go right after the message
       has been filtered according to your regular rules, and just before the message should be
       saved in your mailbox:

           cc $DEFAULT
           xfilter "reformail -r -t"
           /^To:.*/
           getaddr($MATCH) =~ /^.*/;

           MATCH=tolower($MATCH)
           flock "vacation.lock" {
                   `fgrep -iqx "$MATCH" vacation.lst 2>/dev/null || { \
                             echo "$MATCH" >>vacation.lst ; \
                             exit 1 ; \
                         } `
           }
           if ( $RETURNCODE == 0 )
              exit
           to "| ( cat - ; echo ''; cat vacation.msg) | $SENDMAIL"

       This code maintains a list of everyone who sent you mail in the file called vacation.lst.
       When a message is received from anyone that is not already on the list, the address is
       added to the list, and the contents of the file vacation.msg are mailed back to the
       sender. This is intended to reply notify people that you will not be answering mail for a
       short period of time.

       The first statement saves the original message in your regular mailbox. Then, xfilter[2]
       is used to generate an autoreply header to the sender. The To: header in the autoreply -
       which was the sender of the original message - is extracted, and the getaddr[3] function
       is used to strip the person's name, leaving the address only. The file vacation.lst is
       checked, using a lock file to guarantee atomic access and update (overkill, probably).
       Note that the backslashes are required.

       If the address is already in the file, maildrop exits, otherwise the contents of
       vacation.msg are appended to the autoreply header, and mailed out.

           Note
           An easier to make a vacation script is with mailbot(1)[4].

       Here's a version of the vacation script that uses a GDBM database file instead. The
       difference between this script and the previous script is that the previous script will
       send a vacation message to a given E-mail address only once. The following script will
       store the time that the vacation message was sent in the GDBM file. If it's been at least
       a week since the vacation message has been sent to the given address, another vacation
       message will be sent.

       Even though a GDBM database file is used, locking is still necessary because the GDBM
       library does not allow more than one process to open the same database file for writing:

           cc $DEFAULT
           xfilter "reformail -r -t"
           /^To:.*/
           getaddr($MATCH) =~ /^.*/;
           MATCH=tolower($MATCH)
           flock "vacation.lock" {
               current_time=time;
               if (gdbmopen("vacation.dat", "C") == 0)
               {
                  if ( (prev_time=gdbmfetch($MATCH)) ne "" && \
                        $prev_time >= $current_time - 60 * 60 * 24 * 7)
                  {
                      exit
                  }
                  gdbmstore($MATCH, $current_time)
                  gdbmclose
               }
           }
           to "| ( cat - ; echo ''; cat vacation.msg) | $SENDMAIL"

       This script requires that maildrop must be compiled with GDBM support enabled, which is
       done by default if GDBM libraries are present.

       After you return from vacation, you can use a simple Perl script to obtain a list of
       everyone who sent you mail (of course, that can also be determined by examining your
       mailbox).

SEE ALSO

       maildrop(1)[5], maildropfilter(7)[6], reformail(1)[1], mailbot(1)[4], egrep(1), grep(1),
       sendmail(8).

AUTHOR

       Sam Varshavchik
           Author

NOTES

        1. reformail
           http://www.courier-mta.org/maildrop/reformail.html

        2. xfilter
           http://www.courier-mta.org/maildrop/maildropfilter.html#xfilter

        3. getaddr
           http://www.courier-mta.org/maildrop/maildropfilter.html#getaddr

        4. mailbot(1)
           http://www.courier-mta.org/maildrop/mailbot.html

        5. maildrop(1)
           http://www.courier-mta.org/maildrop/maildrop.html

        6. maildropfilter(7)
           http://www.courier-mta.org/maildrop/maildropfilter.html