for (@file1) {
    $h{join ' ',(split / /)[0..3]} = $c++;
}

##</code><code>##

while (<DATA>) {
    $key = join ' ',(split / /)[0..3];
    if (exists $h{$key}) {
         print if $_ ne $file1[$h{$key}];
    }
}

##</code><code>##

use strict;
use warnings;

my ($c, %h, $key);
my @file1 = (
    "A B C D E F G\n",
    "A C B D E F G\n",
    "D B C A E F G\n",
    "B B C D E F G\n"
);

for (@file1) {
    $h{join ' ',(split / /)[0..3]} = $c++;
}

while (<DATA>) {
    $key = join ' ',(split / /)[0..3];
    if (exists $h{$key}) {
         print if $_ ne $file1[$h{$key}];
    }
}

__DATA__
A B C D E F G
A C B D E F H
D B C A I F G
B B C D E F G