wordchange.pl

#!/usr/bin/perl
my $word = shift @ARGV;
my $wordlen = length($word);
my $word2;

if (!@ARGV) {
    $ARGV[0] = '/usr/share/dict/words';
}

while ($word2=<>) {
    chomp $word2;
    my $lendif = length($word2)-$wordlen;
    if ($lendif == 0) {
        $chardif = $word ^ $word2;
        if ($chardif =~ tr/\0//c == 1) {
            print $word2."\n";
        }
    } elsif ($lendif == -1 or $lendif == 1) {
        my($longer, $shorter) = $lendif == 1 ? ($word2, $word) : ($word, $word2);
        for my $index (0..length($longer)-1) {
            if(substr($longer,0,$index).substr($longer,$index+1) eq $shorter) {
                print $word2."\n";
                last;
            }
        }
    }
}