Gee, it seems as if everyone has done this at one time or another... :-)

My approach avoided regular expressions. I just attempted to build a one-to-one mapping between two words. If I could do it, they "matched" in the sense that one could be transformed to the other. When successful, the following function returns a reference to a hash that shows the mapping required to get from the first word to the second. It returns undef on failure.

sub possible_match {
    my ($word1, $word2) = @_;
    return undef unless length( $word1 ) == length( $word2 );
    my ( %one, %two );
    for ( 0 .. length( $word1 ) - 1) {
        my $c1 = substr($word1, $_, 1);
        my $c2 = substr($word2, $_, 1);
        return undef if exists $one{ $c1 } and $one{ $c1 } ne $c2;
        return undef if exists $two{ $c2 } and $two{ $c2 } ne $c1;
        $one{ $c1 } = $c2;
        $two{ $c2 } = $c1;
    }
    return \%one;
}
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-sauoq
"My two cents aren't worth a dime.";