#Program: compareTwoFiles.pl
#The program compares two files and output the data in File2(f2.txt)
#that is not present in File1(f1.txt) into OUTFILE(ot.txt)

#!/usr/bin/perl

use strict;
use warnings;

#declaration of variables
my $file1 = '/opt/programming/work/f1.txt';
my $file2 = '/opt/programming/work/f2.txt';
my $outfile = '/opt/programming/work/of.txt';
my %results = ();

open FILE1, "$file1" or die "Could not open file: $! \n";
while (my $line = <FILE1>){
        chomp($line);
        $results{$line} = 1;
}
close (FILE1);

open (OUTFILE, ">$outfile") or die "Cannot open $outfile for writing: $! \n";
        open FILE2, "$file2" or die "Could not open file: $! \n";
          while (my $line = <FILE2>){
                chomp($line);
                print (OUTFILE $line, "\n") unless defined($results{$line});
          }

        close (FILE2);
close (OUTFILE);