Shell Programming and Scripting

#! /usr/bin/perl -w
use strict;
 
my ($start_time, $end_time, $dt);
 
(@ARGV != 2) && die "Invalid parameters. Exiting";
 
$start_time  = parse_date ($ARGV[0]);
$end_time    = parse_date ($ARGV[1]);
 
open I, "< inputfile.txt";
for (<I>) {
    $dt = parse_date (substr ($_, 0, 20));
    ($dt >= $start_time && $dt <= $end_time) && print;
}
close I;
 
sub parse_date {
    my $t = shift;
    my @d = split /\s+/, $t;
    my %mnths = (   "Jan" => "01", "Feb" => "02", "Mar" => "03", "Apr" => "04", "May" => "05", "Jun" => "06",
                    "Jul" => "07", "Aug" => "08", "Sep" => "09", "Oct" => "10", "Nov" => "11", "Dec" => "12" );
    for (keys %mnths) { if ($d&#91;1] eq $_) { $d[1] = $mnths{$_}; last } }
    $d&#91;3] =~ s/://g;
    return "$d[2]$d[1]$d[0]$d[3]";
}

#! /bin/bash
[ $# -ne 2 ] && echo "Invalid Parameters. Exiting." && exit
 
st_date=`date -d "$1" +%Y%m%d%H%M%S`
nd_date=`date -d "$2" +%Y%m%d%H%M%S`
 
while read x
do
    dt=$(date -d "`echo $x | cut -c1-20`" +%Y%m%d%H%M%S)
    [ $dt -ge $st_date -a $dt -le $nd_date ] && echo $x
done < inputfile.txt