one-liner wars n. A game popular among hackers who code in the language APL (see write-only language and line noise).
The objective is to see who can code the most interesting and/or
useful routine in one line of operators chosen from
APL's exceedingly hairy primitive set. A similar amusement
was practiced among TECO hackers and is now popular among
Perl aficionados.
Ken Iverson, the inventor of APL, has been credited with a
one-liner that, given a number N, produces a list of the
prime numbers from 1 to N inclusive. It looks like this:
(2 = 0 +.= T o.| T) / T <- iN
where `o' is the APL null character, the assignment arrow is a
single character, and `i' represents the APL iota.