Help (command)

In computing,   is a command in various command line shells such as,  , Bash, qshell, 4DOS/4NT, Windows PowerShell, Singularity shell, Python, MATLAB and GNU Octave. It provides online information about available commands and the shell environment.

Implementations
The command is available in operating systems such as Multics, Heath Company HDOS, CP/M Plus, DOS, IBM OS/2, eComStation, ArcaOS, IBM i, Microsoft Windows, ReactOS, THEOS/OASIS, Zilog Z80-RIO, Microware OS-9, Stratus OpenVOS, HP MPE/iX, Motorola VERSAdos, KolibriOS and also in the DEC RT-11, RSX-11, TOPS-10 and TOPS-20 operating systems. Furthermore it is available in the open source MS-DOS emulator DOSBox and in the EFI shell.

On Unix, the command is part of the Source Code Control System and prints help information for the SCCS commands.

Multics
The Multics  command prints descriptions of system commands/active functions and subroutines. It also prints various information about the system status, system changes, and other general information. This information is selected from segments maintained online, which are in a special format, called information segments. More than 800 information segments are available.

DEC OS/8
The DEC OS/8 CCL  command prints information on specified OS/8 programs.

MS-DOS
The  command is available in MS-DOS 5.x and later versions of the software. The  command with a 'command' parameter would give help on a specific command. If no arguments are provided, the command lists the contents of.

In MS-DOS 6.x this command exists as.

The MS-DOS 6.xx  command uses QBasic to view a quickhelp   file, which contains more extensive information on the commands, with some hyperlinking etc. The MS-DOS 6.22 help system is included on Windows 9x CD-ROM versions as well.

PC DOS
In PC DOS 5 and 6  is the same form as MS-DOS 5   command.

PC DOS 7.xx  uses   to open OS/2 style INF files (,   and  ), opening these to the appropriate pages.

PC-MOS
The Software Link's PC-MOS includes an implementation of. Like the rest of the operating system, it is licensed under the GPL v3.

DR-DOS
In DR-DOS,  is a batch file that launches DR-DOS' internal help program,.

ROM-DOS
Datalight ROM-DOS includes an implementation of the help command. ROM-DOS was introduced in 1989 as an MS-DOS compatible operating system designed for embedded systems.

FreeDOS
The FreeDOS version was developed by Joe Cosentino.

4DOS/4NT
The 4DOS/4NT  command uses a text user interface to display the online help.

cmd.exe
Used without parameters,  lists and briefly describes every system command. Windows NT-based versions use MS-DOS 5 style help. Versions before Windows Vista also have a Windows help file ( or  ) in a similar style to MS-DOS 6.

PowerShell
In PowerShell,  is a short form (implemented as a PowerShell function) for access to the   Cmdlet.

Windows PowerShell includes an extensive, console-based help system, reminiscent of man pages in Unix. The help topics include help for cmdlets, providers, and concepts in PowerShell.

GNU Bash
In Bash, the builtin command ' lists all Bash builtin commands if used without arguments. Otherwise, it prints a brief summary of a command. Its syntax is: help [-dms] [pattern]

OpenVMS
HELP is a DCL utility that contains information on the use of commands and descriptions of some OpenVMS concepts such as time formats and lexical functions, as well as lists of commands for a particular purpose (HELP Hints).

Syntax
The command-syntax is: help [command]

Arguments:
 *   This command-line argument specifies the name of the command about which information is to be displayed.