Shell Programming and Scripting

#! /usr/local/bin/perl
use strict;
use Tie::IxHash;
my @mArr = qw/rahul_abc_Linux_Nov_02 rahul_def_Linux_Nov_02 vineet_cde_Linux_Dec_05 vineet_def_Linux_Dec_01 vineet_kbc_Linux_Dec_
06/;
my %mMonth=("Jan"=>"1","Feb"=>"2","Mar"=>"3","Apr"=>"4","May"=>"5","Jun"=>"6","Jul"=>"7","Aug"=>"8","Sep"=>"9","Oct"=>"10","Nov"=
>"11","Dec"=>"12");
my %mHash = ();
tie(%mHash,"Tie::IxHash");
foreach my $mEle ( @mArr )
{
   my @tArr = split(/\_/,$mEle);
   my $mKey1 = $tArr[1];
   if ( defined $mHash{$mKey1} )
   {
      my $val = $mHash{$mKey1};
      my @Arr = split(/\_/,$val);
      my $mExistMonth = $Arr[3];
      my $mNewMonth = $tArr[3];
      if ( $mMonth{$mExistMonth} < $mMonth{$mNewMonth} )
      {
         $mHash{$mKey1}="$mEle";
      }
      elsif ( ( $mMonth{$mExistMonth} == $mMonth{$mNewMonth} ) && $tArr[4] > $Arr[4] )
      {
         $mHash{$mKey1}="$mEle";
      }
   }
   else
   {
      $mHash{$mKey1}="$mEle";
   }
}
print "The Output is\n################\n\n";

foreach my $mKey1 ( keys %mHash )
{
   print "$mHash{$mKey1}\n";
}

# awk -F\_ '{a[$2""$3]=b++" "$0}END{for (i in a) {print a[i]}}' infile|sort|awk '{print $2}'
rahul_abc_Linux_Nov_02
vineet_cde_Linux_Dec_05
vineet_def_Linux_Dec_01
vineet_kbc_Linux_Dec_06