note Cristoforo A solution using [mod://Date::Parse]. <c>#!/usr/bin/perl use strict; use warnings; use Date::Parse qw/ str2time /; #my ($start, $end) = map str2time($_), qw/ 01-Dec-2011 11-Dec-2011 /; my ($start, $end) = map str2time($_), @ARGV; while (<DATA>) { (my $date = (split /,/)[3]) =~ s/_.+//; my $time = str2time( $date ); print if $start <= $time && $time <= $end; } __DATA__ ABC01, 91XYZ889=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 02-Dec-2011_00.34.51, bigFatLog_02-Dec-2011_00.34.06.log ABC03, 93XYZ272=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 07-Dec-2011_09.21.58, bigFatLog_07-Dec-2011_09.20.57.log ABC02, 93XYZ807=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 08-Dec-2011_23.00.15, bigFatLog_08-Dec-2011_22.59.34.log ABC05, 91XYZ525=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 10-Dec-2011_10.01.36, bigFatLog_10-Dec-2011_10.01.00.log ABC01, 93XYZ252=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 12-Dec-2011_11.58.23, bigFatLog_12-Dec-2011_11.57.20.log ABC03, 93XYZ543=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 12-Dec-2011_23.34.07, bigFatLog_12-Dec-2011_23.33.23.log ABC04, 92XYZ066=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 13-Dec-2011_01.00.31, bigFatLog_13-Dec-2011_00.59.29.log ABC05, 93XYZ184=_=SOMEBODY.NAME@DOMAIN.COM, HighPriority, 13-Dec-2011_01.54.41, bigFatLog_13-Dec-2011_01.54.04.log </c> This assumes there are no embedded commas in the data, so it is safe to just [doc://split] on the comma. Otherwise, a module for parsing comma separated values like [mod://Text::CSV_XS] would be needed to parse the log. <p> And this is how I called it from the command line: <c>C:\Old_Data\perlp>perl t33.pl 20111201 20111211</c> 943322 943322