usage:  /usr/bin/xmodmap [-options ...] [filename]

where options include:
    -display host:dpy            X server to use
    -verbose, -quiet             turn logging on or off
    -n                           don't execute changes, just show like make
    -e expression                execute string
    -pm                          print modifier map
    -pk                          print keymap table
    -pke                         print keymap table as expressions
    -pp                          print pointer map
    -help                        print this usage message
    -grammar                     print out short help on allowable input
    -version                     print program version
    -                            read standard input