### 2.3 Commands for Getting Help

The entire text of this manual is available from the Octave prompt via the command `help -i`. In addition, the documentation for individual user-written functions and variables is also available via the `help` command. This section describes the commands used for reading the manual and the documentation strings for user-supplied functions and variables. See Function Files, for more information about how to document the functions you write.

— Command: help

> Octave's `help` command can be used to print brief usage-style messages, or to display information directly from an on-line version of the printed manual, using the GNU Info browser. If invoked without any arguments, `help` prints a list of all the available operators, functions, and built-in variables. If the first argument is `-i`, the `help` command searches the index of the on-line version of this manual for the given topics.

> For example, the command `help help` prints a short message describing the `help` command, and `help -i help` starts the GNU Info browser at this node in the on-line version of the manual.

> Once the GNU Info browser is running, help for using it is available using the command `C-h`.

The help command can give you information about operators, but not the comma and semicolons that are used as command separators. To get help for those, you must type `help comma` or `help semicolon`.

— Built-in Variable: INFO_FILE

> The variable `INFO_FILE` names the location of the Octave info file. The default value is `"`octave-home`/info/octave.info"`, in which octave-home is the directory where all of Octave is installed.

— Built-in Variable: INFO_PROGRAM

> The variable `INFO_PROGRAM` names the info program to run. Its default initial value is `"`octave-home`/libexec/octave/`version`/exec/`arch`/info"` in which octave-home is the directory where all of Octave is installed, version is the Octave version number, and arch is the system type (for example, `i686-pc-linux-gnu`). The default initial value may be overridden by the environment variable `OCTAVE_INFO_PROGRAM`, or the command line argument `--info-program NAME`, or by setting the value of `INFO_PROGRAM` in a startup script

— Built-in Variable: MAKEINFO_PROGRAM

> The variable `MAKEINFO_PROGRAM` names the makeinfo program that Octave runs to format help text that contains Texinfo markup commands. Its default initial value is `"makeinfo"`.

— Built-in Variable: suppress_verbose_help_message

> If the value of `suppress_verbose_help_message` is nonzero, Octave will not add additional help information to the end of the output from the `help` command and usage messages for built-in commands.