http://www.perlmonks.org?node_id=145765

Not really sure if this should be listed as an obfu or a CUFP, as it really does have qualities of both. On the one hand, it's sorta kinda unreadable, and certainly not what you'd expect a "Hello World" program to be like. On the other, it demonstrates perl's usefulness and power when dealing with regexps and alternate data sources.

I had this idea when I first started out in perl, but hit too many snags at that time. It's only just now, when I was cleaning out my fileshare, that I found and finished it.
#!/usr/bin/perl open(FILE,"$0"); while (<FILE>) { print if $_ =~ s/[^H]*(H)[^e]*(e)[^ll]*(ll)[^o]*(o)[^ + ]*( )[^W]*(W)[^o]*(o)[^r]*(r)[^l]*(l)[^d]*(d).*/$1$2$3$4$5$6$7$8$9$1 +0/; } close(FILE);

Spacewarp

DISCLAIMER:
Use of this advanced computing technology does not imply an endorsement
of Western industrial civilization.