Hello,

Version: 1.2-r102-dirty seems to return 0 when it exits w/ error and when it executes successfully. i ran it with a arg file name that does not exist and while an error message is output:
[E::stk_seq] failed to open the input file/stream.
the return value captured by system() (in perl) or subprocess.call() (in python) is 0. a non-zero return value on error would be most convenient for error detection in scripting.

thanks for this useful tool.