post bits of code you like

i shall start:

open(F,"find -type f|");
while (<F>) {
 $_ = substr($_,2,-1);
 print "$_\n" if $v;
 push @{$dups{substr(`md5sum -b "$_"`,0,31)}}, $_;
}
close(F);

for every file in a directory it checksums the file, then adds the checksum as a key to a hash, the value being an array reference. the filename is then added to the array.

so basically the arrays have a list of files with the same checksum. i use this to find duplicates files.

ackermann function

function Ack(M, N) {
    if (M == 0) return( N + 1 );
    if (N == 0) return( Ack(M - 1, 1) );
    return( Ack(M - 1, Ack(M, (N - 1))) );
}