Typing help at either prompt displays a short help message. You can also type help followed by a unit name. This will invoke a pager on the units database at the point where that unit is defined. You can read the definition and comments that may give more details or historical information about the unit. If your pager allows, you may want to scroll backwards, e.g. with ‘b’, because sometimes a longer comment about a unit or group of units will appear before the definition. You can generally quit out of the pager by pressing ‘q’.
Typing search text will display a list of all
units whose names contain text as a substring along with their
definitions. This may help in the case where you aren’t sure of the
right unit name.
Typing search . will display a list of all units; this can be
helpful if you aren’t sure of an appropriate substring, though examining
the output can be tedious. Here ‘.’ is a special argument to the
search command, not a regular expression. If you want to use a
regular expression to search units and their definitions, the
--list-units option will display a list of all units, which can
be sent to a filter such as grep.
Typing search _ will display a list of all assigned runtime
variables—whose names begin with ‘_’—without including all
units whose names simply contain ‘_’.
See Variables Assigned at Run Time for more information on runtime
variables.
Typing version will display the units version
number; unlike the --version option, only the version
number is shown, regardless of any other settings. Full
information is available with the info command.
Typing info will display the same information as the
--info option, described in Invoking units.
Many values set by command-line options can also be set interactively by typing set option=value; typing set option will show the value for that option. Typing set will show a list of options that can be set; options set to other than default values will have a prepended ‘*’. See Setting Options Interactively for more information.