The "help" command:

Display information on how to use TOPIC, which may be a command, webpage, or setting. Webpage names begin with "/". If TOPIC is omitted, a list of topics is returned.

The following options can be used when TOPIC is omitted:

-a|--all

List both common and auxiliary commands

-o|--options

List command-line options common to all commands

-s|--setting

List setting names

-t|--test

List unsupported "test" commands

-v|--verbose

List both names and help text

-x|--aux

List only auxiliary commands

-w|--www

List all web pages

-f|--full

List full set of commands (including auxiliary and unsupported "test" commands), options, settings, and web pages

-e|--everything

List all help on all topics

These options can be used when TOPIC is present:

-h|--html

Format output as HTML rather than plain text

-c|--commands

Restrict TOPIC search to commands