Question

For example :

File 1:

Apple
Orange
grapes

File 2:

Orange
grapes
Apple 

I am trying to check whether both files have the same data in different order.

How to do it without using any external module?

Answer 1

use strict;
use warnings;

# $d{LINE} = TALLY
my ($n, %d) = (1);
while (<>){
    $d{$_} += $n;
    $n *= -1 if eof;
}

# Now get whatever kind of lines you are interested in.
my @same_in_both_files = grep { $d{$_} == 0 } keys %d;
my @surplus_in_file1   = grep { $d{$_} >  0 } keys %d;
my @surplus_in_file2   = grep { $d{$_} <  0 } keys %d;

# Or just get a true-false verdict.
my $files_differ = 1 if grep $_, values %d;