in reply to diff not working as it should

You did not specify a CONTEXT parameter.

It defaults to 3.

Changing your code to this will produce the desired output:

my $diff = diff "after.txt", "before.txt", { OUTPUT => \*STDOUT, STYLE + => "Table", CONTEXT=>0 }; # Um - I used *STDOUT to test..

            "Battle not with trolls, lest ye become a troll; and if you gaze into the Internet, the Internet gazes also into you."
        -Friedrich Nietzsche: A Dynamic Translation