[zokier]

GNU sleep is around 150 loc, and does significantly less...

[glandium]

GNU programs are not a reference. They must have usage(), and handle --help and --version. Even /bin/true.

  coreutils-8.25$ wc -l src/true.c
  80 src/true.c

[liviu-]

Ding has `--version`, and a help message too :P

To be honest, a big chunk of it is just handling user input and attempting to provide useful error messages.