NAME
    Logfile::Rotate - Perl module to rotate logfiles.

SYNOPSIS
       use Logfile::Rotate;
       my $log = new Logfile::Rotate( File   => '/var/adm/syslog/syslog.log', 
                                      Count  => 7,
                                      Gzip  => 'lib',
                                      Post   => sub{ 
                                        open(IN, "/var/run/syslog.pid");
                                        kill("HUP", chomp(<IN>)); }
                                      Dir    => '/var/log/old',
                                      Flock  => 'yes',
                                      Persist => 'yes',
                                    );

       # process log file 

       $log->rotate();

       or
   
       my $log = new Logfile::Rotate( File  => '/var/adm/syslog', 
                                      Gzip   => '/usr/local/bin/gzip');
   
       # process log file 

       $log->rotate();
       undef $log;

DESCRIPTION
    I have used the name space of the Logfile::Base manpage package by
    *Ulrich Pfeifer*, as the use of this module closely relates to the
    processing logfiles.

    new `new' accepts the following arguments, `File', `Count', `Gzip',
        `Pre', `Post', `Flock' and `Dir' with only `File' being mandatory.
        `new' will open and lock the file, so you may co-ordinate the
        processing of the file with rotating it. The file is closed and
        unlocked when the object is destroyed, so you can do this explicitly
        by `undef''ing the object.

        The `Pre'/`Post' arguments allow you to pass function references to
        this method, which you may use as a callback for any processing you
        want before or after the rotation. For example, you may notify the
        process writing to the file that it has been rotated.

        The `Pre' function is passed the current filename to be rotated as
        an argument and the `Post' function is passed the current filename
        that was rotated and that file's new filename including any
        extension added by compression previously.

        Both the `Pre' and `Post' function references you provide are
        executed within an `eval' statement inside the `rotate' method. If
        the `eval' returns an error then the `rotate' method will croak at
        that point.

        The `Signal' argument is deprecated by the `Post' argument.

        The `Flock' argument allows you to specify whether the perl function
        `flock' is used to lock the file during the rotation operation.
        Apparently flock causes problems on some platforms and this option
        has been added to allow you to control the programs behaviour. By
        default the file will be locked using `flock'.

        The `Persist' argument allows you to control whether the program
        will try and set the current log file ownership and permissions on
        any new files that may be created by the rotation. In some
        circumstances the program doing the file rotation may not have
        sufficient permission to `chown' on the file. By default the program
        will try and preserve ownership and permissions.

    rotate()
        This method will copy the file passed in `new' to a file of the same
        name, with a numeric extension and truncate the original file to
        zero length. The numeric extension will range from 1 up to the value
        specified by Count, or 7 if none is defined, with 1 being the most
        recent file. When Count is reached, the older file is discarded in a
        FIFO (first in, first out) fashion. If the argument `Dir' was given,
        all old files will be placed in the specified directory.

        The `Post' function is the last step executed by the rotate method
        so the return code of rotate will be the return code of the function
        you proved, or 1 by default.

        The copy function is implemented by using the the File::Copy manpage
        package, but I have had a few people suggest that they would prefer
        the File::Move manpage. I'm still not decided on this as you would
        loose data if the move should fail.

  Optional Compression

    If available `rotate' will also compress the file with the the gzip
    manpage program or the program passed as the `Gzip' argument.

    You may now also use `lib' as a value for the `Gzip' argument. This
    directs the program to load the `Compress::Zlib' module, if available
    and use it do the compression within perl. This avoids the security
    issues associated with spawning external programs and is the recommended
    value for this option.

    If no argument is defined it will first check to see if the
    `Compress::Zlib' module can be loaded then check the perl the Config
    manpage to determine if gzip is available on your system. In this case
    the the gzip manpage must be in your current path to succeed, and accept
    the `-f' option.

    See the the section on "WARNING" section below.

  Optional Relocation Directory

    If you specify an argument for `Dir' then the file being rotated will be
    relocated to the directory specified. Along with any other files that
    may have been rotated previously. If the directory name specified does
    not exist then it will be created with `0750' permissions. If you wish
    to have other permissions on the directory then I would recommend you
    create the directory before using this module.

    See the the section on "WARNING" section below.

WARNING
    If a system call is made to gzip this makes this module vulnerable to
    security problems if a rogue gzip is in your path or gzip has been
    sabotaged. For this reason a STRONGLY RECOMMEND you DO NOT use this
    module while you are ROOT.

    For a more secure alternative install the `Compress::Zlib' module and
    use the lib value for the `Gzip' argument.

    If you specify an argument for `Dir' and the directory name you pass
    does not exist, this module will create the directory with permissions
    `0750'.

DEPENDANCIES
    See the File::Copy manpage.

    If `Gzip' is being used it must create files with an extension of `.gz'
    for the file to be picked by the rotate cycle.

COPYRIGHT
    Copyright (c) 1997-99 Paul Gampe. All rights reserved. This program is
    free software; you can redistribute it and/or modify it under the same
    terms as Perl itself.

    IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
    DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING
    OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES
    THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE POSSIBILITY OF
    SUCH DAMAGE.

    THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
    THIS SOFTWARE IS PROVIDED ON AN ``AS IS'' BASIS, AND THE AUTHORS AND
    DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
    UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

SEE ALSO
    the File::Copy manpage, the Logfile::Base manpage, the flock manpage
    Changes file for change history and credits for contributions.

RETURN
    All functions return 1 on success, 0 on failure.

AUTHOR
    Paul Gampe <paulg@apnic.net>