Quoting POSIX[0]:
"Care should be taken, also, to call _exit() rather than exit() if exec cannot be used, since
exit() flushes and closes standard I/O channels, thereby damaging the parent process' standard
I/O data structures. (Even with fork(), it is wrong to call exit(), since buffered data would
then be flushed twice.)"
[0]: http://pubs.opengroup.org/onlinepubs/009695399/functions/vfork.html
1) fix usage().
2) sort includes and comment properly. rename rbeg and rend to r0 and r1.
3) argc style and usage fixes.
4) make error-messages clearer.
5) BUGFIX: It was ignored when fork() failed.
6) Don't call enprintf() after execvp and use _exit instead.
Hiltjo Posthuma
FRIGN
sin
Evan Gates