Update the args library to print the default value for an option as well when printing help.
Illustrated by the output of dix_xmit -h below (Note the ". Default [...]"):
Usage: ./dix_xmit [options] IX Dolphin based transmitter
Options are as follows: -h, --help Show this help. -b mbuf name Input buffer name. Default [local_dc] -m [20-100] Input buffer size in mb. Default [100] -g [0-3] The IX memory group to output to. Default [0] -p epics prefix The prefix for epics PVs that report status -l filename Log file name -v Verbose output