How's this different from the 'Just another Perl Hacker' programs (except that it prints a different text) that have been floating around in the Perl community for eons?

You might want to take a look at the file 't/japh/abigail.t' in the Perl distribution. Just substitute the appropriate strings such that it prints 'Hello world' instead of 'Just another Perl Hacker'.

# Computed goto, self modifying code, a loop with an unconditional
# jumps, that terminates anyway, uses strict, warnings and POD,
# and fits in a single line less than 80 characters:
perl -Mstrict -we '$_ = "goto F.print chop;\n=dlroW olleH";F1:eval'
[download]

Abigail