NAME

       mail-expire - program to extract outdated messages from mbox files

SYNOPSIS

       mail-expire AGE FILES...

DESCRIPTION

       mail-expire is a small utility which only purpose is to help on keeping the size of multiple mail folders
       as small as needed (by removing outdated messages).

       Maildir and Mailbox formats are supported for input, both types are mentioned interchangeably in this
       manual page. Output goes to Mailbox files.

       The old messages are compressed with gzip or xz and stored in the file with the name following the
       pattern MBOXNAME.MONTH_YEAR.gz (or similar).  The reference time for the output filename is calculated
       from the current time minus number of days specified in the first parameter.

       If a file of the same name is found, the default storage strategy is appending a new compressed region to
       the existing file (unless -u option is used).  This allows, for example, to run the expiration in a cron
       job each weekend, while collecting all mails from (roughly) each month into dedicated buckets.  The
       drawback of this appending mode is a slightly reduced compression ratio, the advantage is reduced disk
       usage all the time.  Also, such archives can later be recompressed separately to achive the highst
       compression ratio (like: "mv x.xz x.old.xz && xzcat x.old.xz | xz -9 > x.xz && rm xz.old.xz").

   SPACE REQUIREMENTS
       For Mbox input, additional disk space to store the amount of fresh messages plus a portion of the size of
       expired messages (depending on the output compression).

       For Maildir input, only additional space for a portion of the size of expired messages (depending on the
       output compression) is required.

OPTIONS

       mail-expire recognizes the following options:

       -u  If an existing archive file with the expected filename is found, another filename is to be chosen.
           This happens by appending a suffix like (NUMBER) to the basename.

           This is a legacy option, not compatible with any custom output command.

       -t DIR
           Specifies a different target directory for storing expired mailbox files. Default is the current
           directory.

       -T FILEBASE
           Explicit output target file name for all inputs (i.e. merging all expired mails into the same target
           mbox).  This mostly disables automated name generation (base name and date suffix), only the
           compression suffix (-c option and related) is appended.

       --dry-run, -n
           Only examine input files and directories, no mail data is moved around.

       --delete, -d
           Drop the old messages. No backup will be made, be careful with this option.

       --keep, -k
           Copy the expired messages to output files and keep them in the input file.

       --purge=VALUE, -p VALUE
           Specify how to remove input files or folders after becoming empty. 0: never remove, 1 (default):
           remove empty files but keep folders (also related folders), 2: remove empty Mbox file and Maildir, 3:
           like 2 but also remove the input file if it was empty.

       -v LEVEL
           Verbosity level, where 0 produces no output except for errors, 1 some progress messages, 2 and more
           verbose progress messages.

       -c output-shell-command
           A shell script fragment which is run in order to archive the data.  Default or current value can be
           displayed with -v2 option.

           This command is very delicate, it might destroy the target file.  It might also be suspicious to
           shell injection attacks, quotes are important.

       -X  Shortcut for -c and -s options, compressing with XZ compressor (multiple threads) and .xz file
           suffix.

       -U  Shortcut for -c and -s options, to not compress the output and not have an additional suffix.

       -l  Lockless operation, input Mailboxes are assumed to be not touched by other tools while mail-expire
           runs. By default, it attempts to mimic the behavior of procmail to prevent it from file
           modifications. This option has no effect on Maildir type input. To be used with care, runtime
           conflicts with procmail or other tools MIGHT CAUSE DATA LOSS.

AUTHOR

       This manual page was written by Eduard Bloch. Permission is granted to use, copy, distribute and/or
       modify this document under the terms of the MIT license.