**-^** or just **-**
    Print a short message about the syntax of the command, then exit (NOTE: on Windows just use **-**).
**-+** or just **+**
    Print an extensive usage (help) message, including the explanation of
    any module-specific option (but not the GMT common options), then exit.
**-?** or no arguments
    Print a complete usage (help) message, including the explanation of all options, then exit.
**--PAR**\ =\ *value*
    Temporarily override a GMT default setting; repeatable. See :doc:`/gmt.conf` for parameters.