use warnings; # Great :)
use strict; # Also great :)
# Ok, so here you open the file for INPUT. Great :)
open(my $fh, '<', $file) or die "Could not open file: $!";
# Ok, so here you show the line to the user, mutatis mutan
# But where did you open the file for OUTPUT?
# And where did you write the line (changed when applicable) to
+ the file?
# This code is unnecessary.