fax -V (return code: 2)
Error. Invalid command (--version)
fax help (return code: 1)
Usage:
fax [ r[eceive] [-v] [filename-prefix] ]
fax m[ake] [-l] { postscript-file-name | text-file-name }
fax s[end] [-l] [-v] { -m | telephone-number } filename...
fax { p[rint] | v[iew] | rm } [-l] filename...
fax [ stop | start | st[atus] | q[ueue] ]
fax answer
use -l to create low resolution (98 lpi) faxes
use -m if the number has been dialed manually
use -v for verbose output
if given no arguments, answers the phone and receives a fax.
use VAR=value to set variables (e.g. "fax DEV=cua2 receive")
session logs are written to a file with the date/time as the
file name and extension of .efax.log (except for automatic reception).
fax device is /dev/ttyS1, incoming spool directory is /var/spool/fax