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.

if ($ENV{"HTTP_USER_AGENT"} =~ /MSIE/) {
    print "Location: http://www.mozilla.org/products/firefox/\n\n";
    exit 0;
}