$ cat 938362.pl
#!/usr/bin/perl
use strict;
use warnings;
use Scalar::Util qw(looks_like_number);

my $t;
while ($t = <DATA>) {
    $t=~s/\s+$//;
    print "\ninput = '$t'\n";
    if (looks_like_number($t)) {
        print "looks numeric\n";
        if ($t == 0) {
            print "Gotta have somethin' if ya wanna be with me\n";
        }
        else {
            print "There are $t ways to leave your lover\n";
        }
    }
    else {
        print "non-numeric\n";
        if ($t eq "Godzilla") {
            print "Oh, no! There goes Tokyo, go go $t!\n";
        }
        elsif ($t =~ /horse/i) {
            print "A horse is a horse of course, of course\n";
        }
        else {
            print "insert song lyric here...\n";
        }
    }
}
__DATA__
Godzilla
50
A horse of a different color
0
zebra
$ perl 938362.pl

input = 'Godzilla'
non-numeric
Oh, no! There goes Tokyo, go go Godzilla!

input = '50'
looks numeric
There are 50 ways to leave your lover

input = 'A horse of a different color'
non-numeric
A horse is a horse of course, of course

input = '0'
looks numeric
Gotta have somethin' if ya wanna be with me

input = 'zebra'
non-numeric
insert song lyric here...