or download this
Benchmark: timing 10000000 iterations of comp, exist, regex, regexo...
comp: 53 wallclock secs (53.96 usr + 0.00 sys = 53.96 CPU)
exist: 49 wallclock secs (49.23 usr + 0.00 sys = 49.23 CPU)
regex: 78 wallclock secs (77.40 usr + 0.00 sys = 77.40 CPU)
regexo: 78 wallclock secs (77.12 usr + 0.00 sys = 77.12 CPU)