ifnames --version (return code: 0)
ifnames (GNU Autoconf) 2.69
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+/Autoconf: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>, <http://gnu.org/licenses/exceptions.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Written by David J. MacKenzie and Paul Eggert.
ifnames --help (return code: 0)
Usage: /usr/bin/ifnames [OPTION]... [FILE]...
Scan all of the C source FILES (or the standard input, if none are
given) and write to the standard output a sorted list of all the
identifiers that appear in those files in `#if', `#elif', `#ifdef', or
`#ifndef' directives. Print each identifier on a line, followed by a
space-separated list of the files in which that identifier occurs.
-h, --help print this help, then exit
-V, --version print version number, then exit
Report bugs to <bug-autoconf@gnu.org>.
GNU Autoconf home page: <http://www.gnu.org/software/autoconf/>.
General help using GNU software: <http://www.gnu.org/gethelp/>.