luac5.1 -v (return code: 0)
Lua 5.1.5 Copyright (C) 1994-2012 Lua.org, PUC-Rio
luac5.1 --help (return code: 1)
luac5.1: unrecognized option '--help'
usage: luac5.1 [options] [filenames].
Available options are:
- process stdin
-l list
-o name output to file 'name' (default is "luac.out")
-p parse only
-s strip debug information
-v show version information
-- stop handling options