help (command)

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The end of the HELP command output from RT-11SJ displayed on a VT100.
The BusyBox HELP command

In computing, help is a command in various command line shells such as COMMAND.COM, cmd.exe, Bash, 4DOS/4NT, Windows PowerShell, Singularity shell, Python, MATLAB[1] and GNU Octave.[2] It provides online information about available commands and the shell environment.[3]

Implementations[edit]

The command is available in operating systems such as DOS, IBM OS/2,[4] Microsoft Windows, ReactOS,[5] THEOS/OASIS,[6] Zilog Z80-RIO,[7] Microware OS-9,[8] Stratus OpenVOS,[9] HP MPE/iX,[10] Motorola VERSAdos,[11] KolibriOS[12] and also in the DEC RT-11,[13] TOPS-10[14] and TOPS-20[15] operating systems. Furthermore it is available in the open source MS-DOS emulator DOSBox and in the EFI shell.[16]

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

DEC OS/8[edit]

The DEC OS/8 CCL help command prints information on specified OS/8 programs.[17]

DOS[edit]

MS-DOS[edit]

The help command is available in MS-DOS 5.x and later versions of the software.[18] The help command with a 'command' parameter would give help on a specific command. If no arguments are provided, the command lists the contents of DOSHELP.HLP.

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

The MS-DOS 6.xx help command uses QBasic to view a quickhelp HELP.HLP 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[edit]

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

PC DOS 7.xx help uses view.exe to open OS/2 style INF files (cmdref.inf, dosrexx.inf and doserror.inf), opening these to the appropriate pages.

DR-DOS[edit]

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

FreeDOS[edit]

The FreeDOS version was developed by Joe Cosentino.[19]

4DOS/4NT[edit]

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

Microsoft Windows cmd.exe[edit]

Used without parameters, help 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 (NTCMDS.HLP or NTCMDS.INF) in a similar style to MS-DOS 6.

PowerShell[edit]

In PowerShell, help is a short form (implemented as a PowerShell function) for access to the Get-Help 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[edit]

In Bash, the builtin command help'[20] lists all Bash builtin commands if used without arguments. Otherwise, it prints a brief summary of a command. Its syntax is:

help [-dms] [pattern]

Syntax[edit]

The command-syntax is:

help [command]

Arguments:

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

Examples[edit]

DOSBox[edit]

Z:\>help
If you want a list of all supported commands type help /all .
A short list of the most often used commands:
<DIR     > Directory View.
<CD      > Display/changes the current directory.
<CLS     > Clear screen.
<COPY    > Copy files.
...

Python[edit]

>>> help
Type help() for interactive help, or help(object) for help about object.
>>> help()

Welcome to Python 2.5!  This is the online help utility.

If this is your first time using Python, you should definitely check out
the tutorial on the Internet at https://www.python.org/doc/tut/.

Enter the name of any module, keyword, or topic to get help on writing
Python programs and using Python modules.  To quit this help utility and
return to the interpreter, just type "quit".
...

GNU Octave[edit]

octave-3.0.0.exe:1> help

Help is available for the topics listed below.
Additional help for built-in functions and operators is
available in the on-line version of the manual.  Use the command
`doc <topic>' to search the manual index.
...

See also[edit]

References[edit]

  1. ^ https://www.mathworks.com/help/matlab/ref/help.html
  2. ^ https://octave.sourceforge.io/octave/function/help.html
  3. ^ Microsoft TechNet Help article
  4. ^ http://www.jatomes.com/Help/Os2Cmd.php#HELP
  5. ^ https://github.com/reactos/reactos/blob/master/base/applications/cmdutils/help/help.c/
  6. ^ THEOS/OASIS User′s Handbook
  7. ^ Z80-RIO OPERATING SYSTEM USER'S MANUAL
  8. ^ Paul S. Dayan (1992). The OS-9 Guru - 1 : The Facts. Galactic Industrial Limited. ISBN 0-9519228-0-7.
  9. ^ http://stratadoc.stratus.com/vos/19.1.0/r098-19/wwhelp/wwhimpl/common/html/r098-19.pdf
  10. ^ MPE/iX Command Reference Manual
  11. ^ M68000 Family VERSAdos System Facilities Reference Manual
  12. ^ http://wiki.kolibrios.org/wiki/Shell
  13. ^ http://paleoferrosaurus.com/beta/documents/rt11help.html#HELP
  14. ^ TOPS-10 Operating System Commands Manual (pdf). Digital Equipment Corporation. August 1980. Retrieved 2019-02-17.
  15. ^ "TOPS-20 Command manual" (PDF).
  16. ^ "EFI Shells and Scripting". Intel. Retrieved 2013-09-25.
  17. ^ "Concise Command Language" (CCL)."OS/8 Handbook" (PDF). April 1974. Retrieved 28 November 2017.
  18. ^ Wolverton, Van (2003). Running MS-DOS Version 6.22 (20th Anniversary Edition), 6th Revised edition. Microsoft Press. ISBN 0-7356-1812-7.
  19. ^ http://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/distributions/1.2/repos/pkg-html/help.html
  20. ^ "Bash Reference Manual". www.gnu.org. Retrieved 2016-05-09.

Further reading[edit]

External links[edit]