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

&readfile;

sub readfile{

#open the file 
  my $source = 'test.txt';
  my $dest = 'temp1.txt';
  chomp $source;
  open SOURCE, '<', $source or die "Cannot open '$source' $!";
  open DEST,   '>', $dest   or die "Cannot open '$dest' $!";
  while (<SOURCE>){
    s/(T18)//g;
    print DEST; 
    }   
  close SOURCE;
  close DEST;

}
__DATA__

FF151B8A0283043DB070000
FF161B83264643AAD4370FF
FF171B8581BE0010000FFFF
__END__