The `set` command can be used to set _lots_ of options. No screen is drawn, however, until a `plot`, `splot`, or replot command is given.
The `show` command shows their settings; `show all` shows all the settings.
Options changed using `set` can be returned to the default state by giving the corresponding unset command. See also the reset command, which returns all settable parameters to default values.
If a variable contains time/date data, `show` will display it according to the format currently defined by timefmt, even if that was not in effect when the variable was initially defined.
The `set` and unset commands may optionally contain an iteration clause. See iteration.