Comparing digests of the data is one way to do this i.e. 
use strict;
use warnings;

use Digest::SHA;

open my $in_1, '/tmp/f1.txt';
open my $in_2, '/tmp/f2.txt';

my $hash1 = Digest::SHA::sha1_hex(
        do { local $/; <$in_1> }
);

my $hash2 = Digest::SHA::sha1_hex(
        do { local $/; <$in_2> }
);

die "The files are NOT the same\n" unless $hash1 eq $hash2;
print "The file contents are identical\n";

[download]
If your files are really large i.e. in the order of a few gigabytes you could use md5sum on the command line to compare the files instead : 
md5sum file1 file2 file3 etc

[download]
Identical files will yield identical hashes. This is useful because you do not have to load the entire file into memory first.

In reply to Re: file comparison by bluestar
in thread file comparison by sqspat

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