#!/usr/bin/perl
use strict;
use warnings;

my $timeformat = "*%H:%M:%S%% >"; # Example.

my %replacements = (
    '%' => '\%',
    'a' => '[[:alpha:]]+',
    'H' => '\d{2}',
    'M' => '\d{2}',
    'S' => '\d{2}'
);

$timeformat = quotemeta($timeformat);
$timeformat =~ s/\\\%\\?(.)/$replacements{$1}/eg;

print ("The regular expression is: $timeformat\n");

##</code><code>##

09:12: 5:14:29-!- {more garbage goes here}
09:12: 5:14:37
09:12: 5:14:37


##</code><code>##

2008-12-12 00:39  * {more stuff here}
2008-12-12 01:17 < {data here}
2008-12-12 01:30 
2008-12-12 01:31 


##</code><code>##

(\d{2})(\d{2})([\d\s]\d)(\d{2})(\d{2})
(\d{4})\-(\d{2})\-(\d{2})\ (\d{2})\:(\d{2})\