Just an additional note on that - while your regex is better written as chomp($user) you can make an improvement by using a character class instead of alternation:

You wrote $user =~ s/(\r|\n)//.

You *meant* $user =~ s/(\r|\n)$// since that newline should only occur at the end of the string.

That group is capturing but it doesn't need to $user =~ s/(?:\r|\n)$//. Don't use capturing where it's not needed.

In fact - grouping is wasteful for single character alternation. Use a character class instead $user =~ s/[\r\n]$//.

And even better use chomp() chomp($user).