% Savelogs -- Yet Another Log Rotator
% Jessica L. Parsons <orc@pell.portland.or.us>
% Tue Jan 15 20:43:58 PST 2008
#Savelogs##


The
**savelogs** program rotates logs, optionally saving the old ones elsewhere
and signalling the programs that created the logfiles.

##Description###

`/etc/savelogs.conf` tells **savelogs** which logs to rotate, when to rotate
them, whether to back them up, and what to do after a log is rotated.  
The format of the configuration file is a *filename*, followed by a list
of commands, with punctuation and case ignored:

 * `every` {`day`|`week`|`year`}  
    Rotate the log at this time.  If you tell it  **WEEK** (**YEAR**),
    the rotation will happen on a sunday  (the last sunday of the year).

 * `save` *n* `in` *directory*    
    Save _n_ old logs in the named directory as `o.`_logfile_.
    Any existing `o.` file will
    be renamed to `oo.`_file_ to accomodate the
    new file (so the old `o.log` becomes
    `oo.log`, and so on), up to the number of files you want to save.

 * `touch` _mode_  
    After rotating the old log, create a
    new (empty) log with the given _mode_.

 * `size` _size_  
    Rotate the log if it gets larger than this size.  If you suffix
    the size with  **K**, the size is in kilobytes, and a **M**
    suffix means megabytes.

 * `signal` _action_
    After rotating a log and  `touch`ing it,
    run this command. **savelogs**
    attempts to batch `signal`, so that if multiple logs
    are rotated the actions will only be executed once.

For example, the following configuration file

    /var/adm/syslog EVERY WEEK
                SAVE 2 IN /var/adm/OLD
                TOUCH 644
                SIGNAL "killall -HUP syslogd"

Rotates `/var/adm/syslog` every sunday, creating a
new empty file with mode 644, saving two of the old logs in
`/var/adm/OLD`, and sending a  **HUP** signal
to `syslogd` after it's finished.

##Source Code###

=[Version 1.5](savelogs-1.5.tar.gz)=
    Many many many feature changes

     1. Allow, globally and on a file by file basis, saving
        backups to numbered (_NN.file_) instead of
        dotted (_ooo.file_) names.
     2. Allow, globally and on a file by file basis, backup file
        compression.
     3. Set, globally and on a file by file basis, the format
        of the backup file from _ooo.file_ to _file.ooo_.

    In addition, the code has been ported to more systems,
    from recent versions of [freebsd][] ([macos][], to be
    precise) to modern commercial [linux][]es.

=[Version 1.4](savelogs-1.4.tar.gz)=
    Discard the old handbuilt parser and switch over to using
    [lex][] and [yacc][].  I wanted to do some tweaking of the
    features for **savelogs** and decided that it was enough
    of a pain so that this was the time to discard my hand-built
    parser for a generated one.

=[Version 1.3](savelogs-1.3.tar.gz)=
    This version allows multiple `SIGNAL`s per file, so I can
    do something like rotate many syslogs, hup <cite>syslogd</cite>,
    then hup a [cwatch][] process if and
    only if `/var/log/messages` was one of those syslogs. I also
    made the code more portable by fitting it out with my
    [autoconfiguration scripts][configure].
    **Savelogs** now properly builds on pell, which is an **SLS**
    Linux system, egypt, which is my primary
    [Mastodon][]
    build box, and downbelow, which runs an elderly version
    of [FreeBSD][].

=[Version 1.1](savelogs-1.1.tar.gz)=
    The first version under version control.

[cwatch]: /~orc/Code/cwatch
[configure]: /~orc/Code/configure
[mastodon]: /~mastodon
[freebsd]: http://www.freebsd.org
[lex]: http://dinosaur.compilertools.net/#lex
[yacc]: http://dinosaur.compilertools.net/#yacc
[macos]: http://www.apple.com/macosx
[linux]: http://www.kernel.org