HELP.COM
| Company type | Command |
|---|---|
| Industry | Computing / Software |
| Products | Online command-line help documentation |
In computing, the help command is utilized across a variety of command line shells, including but not limited to COMMAND.COM, cmd.exe, Bash, qshell, 4DOS/4NT, Windows PowerShell, Singularity shell, Python, MATLAB, and GNU Octave. Its primary function is to deliver online documentation regarding the commands available and the shell environment itself.
Implementations
Numerous operating systems incorporate the help command, including Multics, Heath Company's HDOS, CP/M Plus, various versions of DOS, IBM's OS/2, as well as its derivatives like eComStation and ArcaOS. It is also present in IBM i, Microsoft Windows, ReactOS, THEOS/OASIS, Zilog Z80-RIO, Microware OS-9, Stratus OpenVOS, HP MPE/iX, Motorola VERSAdos, KolibriOS, and several DEC platforms such as RT-11, RSX-11, TOPS-10, and TOPS-20. Additionally, this command can be found in the open-source MS-DOS emulator DOSBox and within the Unified Extensible Firmware Interface (EFI) shell environment.
On Unix-based platforms, the help command exists as part of the Source Code Control System (SCCS), offering guidance for SCCS-related commands.
Multics
Within the context of Multics, the help command supplies detailed explanations about system commands, active functions, and available subroutines. It also reports on system status and recent modifications. This information is sourced from over 800 structured online help segments maintained in a proprietary format.
DEC OS/8
For DEC's OS/8 operating system, the Concise Command Language (CCL) implementation of help provides users with information on specific OS/8 software programs.
MS-DOS
Starting from MS-DOS version 5.x, the help command is accessible to users. When combined with a parameter, it offers assistance on particular commands; if invoked without arguments, it displays the contents of DOSHELP.HLP. In MS-DOS 6.x releases, this functionality appears under the name FASTHELP. The help system in MS-DOS 6.xx employs QBasic to render the comprehensive HELP.HLP file featuring hyperlink navigation. This resource is also included on installation media for Windows 9x.
PC DOS
The help command in versions 5 and 6 of PC DOS replicates the behavior found in MS-DOS 5. In PC DOS 7.xx, it utilizes view.exe to open OS/2-style INF files such as cmdref.inf, dosrexx.inf, and doserror.inf, directing users to relevant sections immediately.
PC-MOS
The GPL v3-licensed version of help provided by The Software Link for their PC-MOS operating system aligns with its open-source philosophy.
DR-DOS
In the case of DR-DOS, help is implemented as a batch file that launches an internal utility named dosbook, which serves as the help interface.
ROM-DOS
Developed by Datalight and released in 1989, ROM-DOS is an MS-DOS compatible OS designed specifically for embedded environments. It includes its own version of the help command.
FreeDOS
The FreeDOS edition of the help command was created by Joe Cosentino.
4DOS/4NT
The 4DOS/4NT shells offer their own iteration of the help command that delivers online assistance through a text-based user interface.
cmd.exe
On Windows NT platforms, cmd.exe employs a help system reminiscent of MS-DOS 5, displaying a list of commands alongside concise explanations when executed without arguments. Earlier editions prior to Windows Vista also feature Windows help documentation files such as NTCMDS.HLP or NTCMDS.INF, which resemble those found in MS-DOS 6.
PowerShell
Within PowerShell, the help command serves as an alias for the Get-Help Cmdlet, providing a comprehensive, console-based assistance framework that covers cmdlets, providers, and fundamental concepts, functioning similarly to Unix manual pages.
GNU Bash
For the Bash environment, the internal help command either enumerates all built-in commands or offers brief descriptions. Its syntax is as follows:
help [-dms] [pattern]
OpenVMS
The HELP utility in DCL supplies usage instructions and explanations for OpenVMS commands and concepts such as time formatting and lexical functions. It also includes categorized lists of commands known as HELP Hints.
Syntax
help [command]
command: Indicates the specific command for which information is requested.
DOSBox
<syntaxhighlight lang="doscon"> Z:\>help To view all supported commands, type help /all . Here is a brief selection of frequently used commands: <DIR > Displays directory contents. <CD > Shows or changes the current directory. <CLS > Clears the screen. <COPY > Copies files. ... </syntaxhighlight>
Python
<syntaxhighlight lang="pycon" highlight="3"> >>> help Enter help() for interactive assistance, or help(object) to get information about an object. >>> help()
Welcome to Python 2.5! This interactive help system is now available.
If you are new to Python, consider reviewing the tutorial at https://www.python.org/doc/tut/.
Input any module name, keyword, or topic to receive programming guidance. Type "quit" to exit. ... </syntaxhighlight>
GNU Octave
<syntaxhighlight lang="text" highlight="1"> octave-3.0.0.exe:1> help
Help topics are available for the items listed. Additional documentation for built-in functions and operators can be found in the online manual. Use `doc <topic>` to search the index. ... </syntaxhighlight>