Benchmark: timing 50000 iterations of mybinary, use_grep...
  mybinary: 15 wallclock secs (15.23 usr +  0.03 sys = 15.26 CPU) @ 3276.54/s (n=50000)
  use_grep: 13 wallclock secs (12.83 usr +  0.04 sys = 12.87 CPU) @ 3885.00/s (n=50000)
           Rate mybinary use_grep
mybinary 3277/s       --     -16%
useagrep 3885/s      19%       --