Editing COMMAND.COM

{{short description|Default command line for MS-DOS and Windows 9x}}
{{Redirect|COMMAND|other uses|Command (disambiguation){{!}}Command}}
{{distinguish|cmd.exe}}
{{Use dmy dates|date=April 2019|cs1-dates=y}}
{{Use list-defined references|date=December 2021}}
{{Infobox software
| name = COMMAND.COM
| screenshot = Command.com Win10.png
| caption = COMMAND.COM in [[Windows 10]]
| other_names = MS-DOS Prompt,<br />Windows Command Interpreter
| developer = [[Seattle Computer Products]], [[IBM]], [[Microsoft]], [[The Software Link]], [[Datalight]], [[Novell]], [[Caldera UK|Caldera]]
| released = {{Start date and age|1980}}
| replaced_by = [[cmd.exe]]
| programming language = [[x86]] [[assembly language]]<ref name="Microsoft_COMMAND"/>
| operating_system = {{ubl|[[86-DOS]]|[[MS-DOS]]|[[PC&nbsp;DOS]]|[[DR-DOS]]|[[SISNE plus]]|[[PTS-DOS]]|[[ROM-DOS]]|[[OS/2]]|[[Windows 9x]]|[[Windows NT]] ([[NTVDM]])|[[FreeDOS]]|[[MSX-DOS]]}}
| platform = 16-bit [[x86]]
| genre = [[Command-line interpreter]]
}}
[[File:Microsoft Windows 95 Version 4.00.1111 command.com MS-DOS Prompt 492x259.png|thumb|250px|command.com running in a [[Windows console]] on [[Windows 95]] (MS-DOS Prompt)]]
<code>'''COMMAND.COM'''</code> is the default [[command-line interpreter]] for [[MS-DOS]], [[Windows 95]], [[Windows 98]] and [[Windows Me]]. In the case of DOS, it is the default user interface as well. It has an additional role as the usual first program run after [[Booting|boot]] ([[init process]]). As a shell, COMMAND.COM has two distinct modes of operation: [[Read-eval-print loop|interactive mode]] and [[Batch processing|batch mode]]. Internal commands are commands stored directly inside the COMMAND.COM [[Binary file|binary]]; thus, they are always available, but can only be executed directly from the command interpreter.{{Citation needed|date=March 2024}}

== Description ==
COMMAND.COM's successor on [[OS/2]] and [[Windows NT]] systems is [[cmd.exe]], although COMMAND.COM is available in [[virtual DOS machine]]s on [[IA-32]] versions of those operating systems as well. The {{Mono|COMMAND.COM}} filename was also used by {{ill|Disk Control Program|de|vertical-align=sup}} (DCP), an MS-DOS derivative by the former East German [[VEB Robotron]].<ref name="DCP_2016" />

COMMAND.COM is a DOS program. Programs launched from COMMAND.COM are DOS programs that use the [[DOS API]] to communicate with the disk operating system. The compatible command processor under [[FreeDOS]] is sometimes also called [[FreeCom]].

==Operating modes==
As a shell, COMMAND.COM has two distinct modes of operation. The first is [[Read-eval-print loop|interactive mode]], in which the user types commands which are then executed immediately. The second is [[Batch processing|batch mode]], which executes a predefined sequence of commands stored as a text file with the [[Batch file|.BAT]] extension.

=={{anchor|Prompt}}Internal commands==
Internal commands are commands stored directly inside the COMMAND.COM binary. Thus, they are always available but can only be executed directly from the command interpreter.

All commands are executed after the {{keypress|Enter}} key is pressed at the end of the line. COMMAND.COM is not case-sensitive, meaning commands can be typed in any mixture of upper and lower case.

; [[BREAK (DOS command)|BREAK]]: Controls the handling of program interruption with {{keypress|Ctrl|C}} or {{keypress|Ctrl|Break}}.
; [[CHCP (command)|CHCP]]: Displays or changes the current system [[code page]].
; [[CHDIR|CHDIR, CD]]: Changes the current [[working directory]] or displays the current directory.
; [[CLS (DOS command)|CLS]]: Clears the screen.
; [[COPY (DOS command)|COPY]]: Copies one file to another (if the destination file already exists, MS-DOS asks whether to replace it). (See also [[XCOPY]], an external command that could also copy directory trees).
; [[CTTY (DOS command)|CTTY]]: Defines the device to use for input and output.
; [[DATE (command)|DATE]]: Display and set the date of the system.
; [[DEL (command)|DEL, ERASE]]: Deletes a file. When used on a directory, deletes all files inside the directory only. In comparison, the external command [[DELTREE]] deletes all subdirectories and files inside a directory as well as the directory itself.
; [[DIR (command)|DIR]]: Lists the files in the specified directory.
; [[ECHO (command)|ECHO]]: Toggles whether text is displayed ({{codett|ECHO ON}}) or not ({{codett|ECHO OFF}}). Also displays text on the screen ({{codett|ECHO text}}).
; [[EXIT (command)|EXIT]]: Exits from COMMAND.COM and returns to the program which launched it.
; [[LFNFOR]]: Enables or disables the return of [[long filename]]s by the FOR command. ([[Windows 9x]]).{{Citation needed|date=March 2024}}
; [[LOADHIGH|LOADHIGH, LH]]: Loads a program into [[Upper Memory Area|upper memory]] ({{codett|HILOAD}} in [[DR DOS]]).
; [[LOCK (DOS command)|LOCK]]: Enables external programs to perform low-level disk access to a volume. ([[MS-DOS 7.1]] and [[Windows 9x]] only){{Citation needed|date=March 2024}}
; [[MKDIR|MKDIR, MD]]: Creates a new directory.
; [[PATH (DOS command)|PATH]]: Displays or changes the value of the PATH [[environment variable]] which controls the places where COMMAND.COM will search for executable files.
; [[PROMPT (DOS command)|PROMPT]]: Displays or change the value of the PROMPT environment variable which controls the appearance of the prompt.
; [[REN (command)|RENAME, REN]]: Renames a file or directory.
; [[RMDIR|RMDIR, RD]]: Removes an empty directory.
; [[SET (DOS command)|SET]]: Sets the value of an [[environment variable]]; without arguments, shows all defined environment variables.
; [[TIME (command)|TIME]]: Display and set the time of the system.
; [[TRUENAME]]: Display the fully expanded physical name of a file, resolving [[ASSIGN (DOS command)|ASSIGN]], [[JOIN (DOS command)|JOIN]] and [[SUBST]] logical filesystem mappings.<ref name="Paul_1997_NWDOSTIP"/>
; [[TYPE (DOS command)|TYPE]]: Display the content of a file on the console.
; [[UNLOCK (DOS command)|UNLOCK]]: Disables low-level disk access. (MS-DOS 7.1 and [[Windows 9x]] only){{Citation needed|date=March 2024}}
; [[VER (command)|VER]]: Displays the version of the [[operating system]].
; [[VERIFY (DOS command)|VERIFY]]: Enable or disable verification of writing for files.
; [[VOL (command)|VOL]]:Shows information about a volume.

=== Batch file commands ===
[[Control structure|Control structures]] are mostly used inside batch files, although they can also be used interactively.<ref name="Caldera_1998_USER_CH7" /><ref name="Paul_1997_NWDOSTIP" />

; <nowiki>:</nowiki>''label'': Defines a target for GOTO.
; [[CALL (DOS command)|CALL]]: Executes another batch file and returns to the old one and continues.
; [[FOR (DOS command)|FOR]]: Iteration: repeats a command for each out of a specified set of files.
; [[GOTO]]: Moves execution to a specified label. Labels are specified at the beginning of a line, with a colon ({{codett|:likethis}}).
; [[IF (DOS command)|IF]]: Conditional statement, allows branching of the program execution.
; [[PAUSE (DOS command)|PAUSE]]: Halts execution of the program and displays a message asking the user to press [[any key]] to continue.
; [[REM (DOS command)|REM]]: [[comment (computer programming)|comment]]: any text following this command is ignored.
; [[SHIFT (DOS command)|SHIFT]]: Replaces each of the [[replacement parameter]]s with the subsequent one (e.g. {{codett|%0}} with {{codett|%1}}, {{codett|%1}} with {{codett|%2}}, etc.).

==== IF command ====
On exit, all external commands submit a [[return code]] (a value between 0 and 255) to the calling program. Most programs have a certain convention for their return codes (for instance, 0 for a successful execution).<ref name="Paul_1997_BATTIPS"/><ref name="FD_2003_Errorlevel"/><ref name="Paul_2003_Exitcodes"/><ref name="Allen_2005"/>

If a program was invoked by COMMAND.COM, the internal IF command with its ERRORLEVEL conditional can be used to test on error conditions of the last invoked external program.{{Citation needed|date=March 2024}}

Under COMMAND.COM, internal commands do not establish a new value.{{Citation needed|date=March 2024}}

==Variables==
Batch files for COMMAND.COM can have four kinds of variables:
* [[Environment variable]]s: These have the {{mono|%VARIABLE%}} form and are associated with values with the SET statement. Before DOS 3 COMMAND.COM will only expand environment variables in batch mode; that is, not interactively at the command prompt.{{citation needed|date=August 2017}}
* [[Replacement parameter]]s: These have the form {{mono|%0}}, {{mono|%1}}...{{mono|%9}}, and initially contain the command name and the first nine [[command-line parameter]]s passed to the script (e.g., if the invoking command was {{kbd|myscript.bat John Doe}}, then {{mono|%0}} is "myscript.bat", {{mono|%1}} is "John" and {{mono|%2}} is "Doe").  The parameters to the right of the ninth can be mapped into range by using the SHIFT statement.{{Citation needed|date=March 2024}}
* Loop variables: Used in loops, they have the {{mono|%%a}} format when run in batch files. These variables are defined solely within a specific FOR statement, and iterate over a certain set of values defined in that FOR statement.{{Citation needed|date=March 2024}}
* Under [[Novell DOS 7]]<!-- 1993 -->, [[OpenDOS 7.01]], [[DR-DOS 7.02]] and higher, COMMAND.COM also supports a number of [[system information variable]]s,<ref name="Caldera_1998_USER_CH7"/><ref name="Caldera_1998_USER"/><ref name="Paul_1997_NWDOSTIP"/> a feature earlier found in [[4DOS 3.00]]<!-- 1990 --> and higher<ref name="4DOS_8.00_HELP"/> as well as in [[Multiuser DOS]],<!-- 1991 --><ref name="Paul_1997_NWDOSTIP"/><!-- not in CDOS 386 1.0 (1987), not sure about CDOS 386 3.0 (1989) --> although most of the supported variable names differ.

==Redirection, piping, and chaining==
Because DOS is a single-tasking operating system, [[Pipeline (software)|piping]] is achieved by running commands sequentially, redirecting to and from a [[temporary file]].{{Citation needed|date=March 2024}} COMMAND.COM makes no provision for redirecting the [[Standard streams#Standard error (stderr)|standard error]] channel.{{Citation needed|date=March 2024}}

; <code>''command'' < ''filename''</code> : Redirect [[Standard streams#Standard input (stdin)|standard input]] from a file or device
; <code>''command'' > ''filename''</code> : Redirect [[Standard streams#Standard output (stdout)|standard output]], overwriting target file if it exists.
; <code>''command'' >> ''filename''</code> : Redirect [[Standard streams#Standard output (stdout)|standard output]], appending to target file if it exists.
; <code>''command1'' | ''command2''</code> : Pipe [[Standard streams#Standard output (stdout)|standard output]] from ''command1'' to [[Standard streams#Standard input (stdin)|standard input]] of ''command2''
; <code>''command1'' ¶ ''command2''</code> :
: Commands separated by ASCII-20 (¶, invoked by {{keypress|Ctrl|T}}) are executed in sequence (chaining of commands).<ref name="Paul_1997_NWDOSTIP"/> In other words, first ''command1'' is executed until termination, then ''command2''.<ref name="Paul_1997_NWDOSTIP"/> This is an undocumented feature in COMMAND.COM of [[MS-DOS 5.0|MS-DOS]]/[[PC DOS 5.0]]<!-- tested MS-DOS 6.2 and PC DOS 7 --> and higher.<ref name="Paul_1997_NWDOSTIP"/> It is also supported by COMMAND.COM<!-- but not by CMD --> of the Windows NT family<!-- tested Windows XP --> as well as by DR-DOS 7.07. All versions of DR-DOS COMMAND.COM<!-- since 3.xx --> already supported a similar internal function utilizing an exclamation mark (!) instead (a feature originally derived from [[Concurrent DOS]] and [[Multiuser DOS]]) - in the single-user line this feature was only available internally (in built-in startup scripts like "!DATE!TIME") and indirectly through [[DOSKEY]]'s $T parameter to avoid problems with ! as a valid filename character.<ref name="Paul_1997_NWDOSTIP"/> [[4DOS]] supports a configurable command line separator ([[4DOS.INI]] CommandSep= or SETDOS /C), which defaults to ^.<ref name="4DOS_8.00_HELP"/> COMMAND.COM in newer versions of Windows NT<!-- works for example in XP, but not in MS-DOS/PC DOS COMMAND.COM --> also supports an {{code|&}} separator for compatibility with the cmd syntax in OS/2 and the Windows NT family.<ref name="4DOS_8.00_HELP"/> (cmd does not support the ¶ separator.)

==Limitations==
Generally, the command line length in interactive mode is limited to 126 characters.<ref name="Paul_1997_MSDOS"/><ref name="Paul_1997_4DOSTIP"/><ref name="Schulman_1994_Undocumented-DOS"/> In [[MS-DOS 6.22]], the command line length in interactive mode is limited to 127 characters.{{Citation needed|date=March 2024}}

==In popular culture==

* The message "Loading COMMAND.COM" can be seen on a [[Head-Up Display|HUD]] view of the [[T-800|Terminator]] and the internal viewport of [[RoboCop]] when he reboots.{{Citation needed|date=March 2024}}
* In the animated children's TV series ''[[ReBoot]]'', which takes place inside computers, the leader of a system (the equivalent of a city) is called the COMMAND.COM.{{Citation needed|date=March 2024}}

==See also==

* [[List of DOS commands]]
* [[Comparison of command shells]]
* [[cmd.exe]] — command-line interpreter in various Windows and OS/2 systems
* {{hlist|class=inline|[[IBMBIO.COM]] | [[IO.SYS]]}} — starts the command processor as the first process
* [[SHELL (CONFIG.SYS directive)]] — to override default command processor
* [[COMSPEC (environment variable)]] — set by COMMAND.COM to reload transient portion of itself
* [[CMDLINE (environment variable)]] — set by COMMAND.COM to pass long command lines to external programs
* {{hlist|class=inline|[[4DOS]] | [[NDOS]]}} — third-party replacement command processors
* [[DOSSHELL]] / [[ViewMAX]] — alternative DOS shells
<!-- * [[TASKMAX]] / [[TASKMGR]] — instances daughter processes -->
* {{hlist|class=inline|[[Concurrent DOS]] | [[Multiuser DOS]] | [[REAL/32]]}} — have similar command processors not named COMMAND.COM
* [[PC-MOS/386]] — has a similar command processor also named COMMAND.COM
* [[Transient Program Area]] — memory available for use either by the running application or the transient portion of COMMAND.COM
* [[SpartaDOS X]] — a similar implementation for Atari computers

==References==
{{Reflist|1|refs=
<ref name="Microsoft_COMMAND">{{Cite web|url=https://github.com/microsoft/MS-DOS/blob/master/v2.0/source/COMMAND.ASM|title=MS-DOS/COMMAND.ASM at master · microsoft/MS-DOS|website=GitHub}}</ref>
<ref name="Paul_1997_BATTIPS">{{cite book |title=BATTIPs — Tips & Tricks zur Programmierung von Batchjobs |at=Kapitel 7: ERRORLEVEL abfragen |publisher=MPDOSTIP |author-first=Matthias R. |author-last=Paul |date=1997-05-01 |orig-year=1993-10-01 |language=de |url=http://www.antonis.de/dos/batchtut/battips/index.htm#7 |access-date=2017-08-23 |url-status=live |archive-url=https://web.archive.org/web/20170823191411/http://www.antonis.de/dos/batchtut/battips/index.htm |archive-date=2017-08-23}} (NB. BATTIPS.TXT is part of MPDOSTIP.ZIP. The provided link points to an HTML-converted older version of the BATTIPS.TXT file.) [https://web.archive.org/web/20190601152204/https://www.sac.sk/download/text/mpdostip.zip<!-- A yet older version 155 from 1997-05-13 of the 1997-07-15 distribution archive. -->]</ref>
<ref name="Paul_2003_Exitcodes">{{cite web |title=Exitcodes (errorlevels) of DOS utilities |author-first=Matthias R. |author-last=Paul |editor-first=Eric |editor-last=Auer |date=2003 |orig-year=1997 |url=https://www.auersoft.eu/soft/by-others/dos-exitcodes-en.html |access-date=2017-09-11 |url-status=dead |archive-url=https://archive.today/20170911103337/https://www.auersoft.eu/soft/by-others/dos-exitcodes-en.html |archive-date=11 September 2017 }} [https://www.auersoft.eu/soft/by-others/dos-exitcodes-de.html<!-- https://archive.today/20170911103522/https://www.auersoft.eu/soft/by-others/dos-exitcodes-de.html -->]</ref>
<ref name="Allen_2005">{{cite web |author-first1=William |author-last1=Allen |author-first2=Linda |author-last2=Allen |title=Windows 95/98/ME ERRORLEVELs |url=http://www.allenware.com/mcsw/errorlevels.zip |url-status=dead |archive-url=https://web.archive.org/web/20051029140802/http://www.allenware.com/mcsw/errorlevels.zip |archive-date=2005-10-29}}</ref>
<ref name="FD_2003_Errorlevel">{{cite web |title=MS-DOS errorlevels |author-first1=Eric |author-last1=Auer |author-first2=Matthias R. |author-last2=Paul |author-first3=Jim |author-last3=Hall |author-link3=Jim Hall (computer programmer) |date=2015-12-24 |orig-year=2003-12-31 |url=http://www.freedos.org/technotes/technote/207.html |url-status=dead |archive-url=https://web.archive.org/web/20151224202118/http://www.freedos.org/technotes/technote/207.html |archive-date=2015-12-24}}</ref>
<ref name="Caldera_1998_USER">{{cite book |title=Caldera DR-DOS 7.02 User Guide |publisher=[[Caldera, Inc.]] |date=1998 |orig-year=1993, 1997 |url=http://www.drdos.net/documentation/usergeng/uglontoc.htm |access-date=2013-08-10 |url-status=dead |archive-url=https://web.archive.org/web/20161104235434/http://www.drdos.net/documentation/usergeng/uglontoc.htm |archive-date=2016-11-04}}</ref>
<ref name="Caldera_1998_USER_CH7">{{cite book |title=Caldera DR-DOS 7.02 User Guide |publisher=[[Caldera, Inc.]] |date=1998 |orig-year=1993, 1997 |chapter=Chapter 7: Batch Processing |chapter-url=http://www.drdos.net/documentation/usergeng/07ugch7.htm |access-date=2017-09-11 |url-status=dead |archive-url=https://web.archive.org/web/20170911163945/http://www.drdos.net/documentation/usergeng/07ugch7.htm |archive-date=2017-09-11}}</ref>
<ref name="Paul_1997_MSDOS">{{cite book |title=MSDOSTIPs — Tips für den Umgang mit MS-DOS 5.0-7 |publisher=MPDOSTIP |author-first=Matthias R. |author-last=Paul |date=1997-07-01 |orig-year=1994-01-01 |language=de |url=http://www.antonis.de/dos/dos-tuts/mpdostip/html/msdostip.htm |access-date=2013-10-25 |url-status=live |archive-url=https://web.archive.org/web/20170822214030/http://www.antonis.de/dos/dos-tuts/mpdostip/html/msdostip.htm |archive-date=2017-08-22}} (NB. MSDOSTIP.TXT is part of MPDOSTIP.ZIP, maintained up to 2001 and distributed on many sites at the time. The provided link points to a HTML-converted older version of the MSDOSTIP.TXT file.) [https://web.archive.org/web/20190601152204/https://www.sac.sk/download/text/mpdostip.zip<!-- A yet older version 155 from 1997-05-13 of the 1997-07-15 distribution archive. -->]</ref>
<ref name="4DOS_8.00_HELP">{{quote|source={{cite book |title=4DOS 8.00 online help |title-link=4DOS 8.00 |author-first1=Hardin |author-last1=Brothers |author-first2=Tom |author-last2=Rawson |author-link2=Tom Rawson |author-first3=Rex C. |author-last3=Conn |author-link3=Rex C. Conn |author-first4=Matthias R. |author-last4=Paul |author-first5=Charles E. |author-last5=Dye |author-first6=Luchezar I. |author-last6=Georgiev |date=2002-02-27}} |text=[...] Multiple Commands: You can type several commands on the same command line, separated by a caret [^]. For example, if you know you want to copy all of your .TXT files to drive A: and then run CHKDSK to be sure that drive A's file structure is in good shape, you could enter the following command: {{code|C:\>COPY *.TXT A: ^ CHKDSK A:|doscon}} You may put as many commands on the command line as you wish, as long as the total length of the command line does not exceed 511 characters. You can use multiple commands in aliases and batch files as well as at the command line. If you don't like using the default command separator, you can pick another character using the {{code|SETDOS /C}} command or the CommandSep directive in [[4DOS.INI]]. [...] {{code|SETDOS /C:}} (Compound character) This option sets the character used for separating multiple commands on the same line. The default is the caret [^]. You cannot use any of the redirection characters [<>{{!}}], or the blank, tab, comma, or equal sign as the command separator. The command separator is saved by SETLOCAL and restored by ENDLOCAL. This example changes the separator to a tilde [~]: {{code|C:\>SETDOS /C~|doscon}} (You can specify either the character itself, or its ASCII code as a decimal number, or a hexadecimal number preceded by 0x.) [...] CommandSep = c (^): This is the character used to separate multiple commands on the same line. [...] Special Character Compatibility: If you use two or more of our products, or if you want to share aliases and batch files with users of different products, you need to be aware of the differences in three important characters: the Command Separator [...], the Escape Character [...], and the Parameter Character [...]. The default values of each of these characters in each product is shown in the following chart: [...] Product, Separator, Escape Parameter [...] 4DOS: ^, ↑, & [...] 4OS2, 4NT, Take Command: &, ^, $ [...] (The up-arrow [↑] represents the ASCII Ctrl-X character, numeric value 24.) [...]}}</ref>
<ref name="Paul_1997_NWDOSTIP">{{cite book |title=NWDOS-TIPs — Tips & Tricks rund um Novell DOS 7, mit Blick auf undokumentierte Details, Bugs und Workarounds |publisher=MPDOSTIP |author-first=Matthias R. |author-last=Paul |date=1997-07-30 |orig-year=1994-05-01 |edition=3 |version=Release 157 |language=de |url=http://www.antonis.de/dos/dos-tuts/mpdostip/html/nwdostip.htm |access-date=2014-08-06 |url-status=dead |archive-url=https://web.archive.org/web/20161104235829/http://www.antonis.de/dos/dos-tuts/mpdostip/html/nwdostip.htm |archive-date=4 November 2016 }} (NB. The provided link points to a HTML-converted version of the {{code|NWDOSTIP.TXT}}, which is part of the {{code|MPDOSTIP.ZIP}}<!-- still named TIPS_MP.ZIP between 1991 and 1996-11 --> collection.) [https://web.archive.org/web/20190601152204/https://www.sac.sk/download/text/mpdostip.zip<!-- A yet older version 155 from 1997-05-13 of the 1997-07-15 distribution archive. -->]</ref>
<ref name="DCP_2016">{{cite web |title=Betriebssystem DCP |author-first1=Rüdiger |author-last1=Kurth |author-first2=Martin |author-last2=Groß |author-first3=Henry |author-last3=Hunger |date=2016-11-29 |orig-year=2007 |language=de |website=www.robotrontechnik.de |url=http://www.robotrontechnik.de/html/software/dcp.htm |access-date=2019-04-28 |url-status=live |archive-url=https://web.archive.org/web/20190403061152/http://www.robotrontechnik.de/html/software/dcp.htm |archive-date=2019-04-03}}</ref>
<ref name="Paul_1997_4DOSTIP">{{cite web |title=Hinweise zu JPSofts 4DOS 5.5b/c, 5.51, 5.52a und NDOS |work=MPDOSTIP |author-first=Matthias R. |author-last=Paul |date=1997-05-01 |orig-year=1995-03-01 |language=de |url=http://www.antonis.de/dos/dos-tuts/mpdostip/html/4dostip.htm |access-date=2015-05-08 |url-status=live |archive-url=https://web.archive.org/web/20161104211143/http://www.antonis.de/dos/dos-tuts/mpdostip/html/4dostip.htm |archive-date=2016-11-04}} (NB. The provided link points to a HTML-converted version of the {{code|4DOS5TIP.TXT}} file, which is part of the {{code|MPDOSTIP.ZIP}}<!-- still named TIPS_MP.ZIP between 1991 and 1996-11 --> collection.) [https://web.archive.org/web/20190601152204/https://www.sac.sk/download/text/mpdostip.zip<!-- A yet older version 155 from 1997-05-13 of the 1997-07-15 distribution archive. -->]</ref>
<ref name="Schulman_1994_Undocumented-DOS">{{cite book |author-first1=Andrew |author-last1=Schulman |author-first2=Ralf D. |author-last2=Brown |author-link2=Ralf D. Brown |author-first3=David |author-last3=Maxey |author-first4=Raymond J. |author-last4=Michels |author-first5=Jim |author-last5=Kyle |title=Undocumented DOS: A programmer's guide to reserved MS-DOS functions and data structures - expanded to include MS-DOS 6, Novell DOS and Windows 3.1 |publisher=[[Addison Wesley]] |edition=2 |date=1994 |orig-year=November 1993<!-- first printing --> |isbn=0-201-63287-X |location=Reading, Massachusetts, US |pages=623, 626 |url-access=registration |url=https://archive.org/details/undocumenteddosp00andr_0}} (xviii+856+vi pages, 3.5"-floppy) Errata: [https://web.archive.org/web/20190417215556/http://www.cs.cmu.edu/afs/cs/user/ralf/pub/books/UndocumentedDOS/errata.ud2] [https://web.archive.org/web/20190417212906/https://www.pcjs.org/pubs/pc/programming/Undocumented_DOS/#errata-2nd-edition]</ref>
}}

==Further reading==
{{quote box|width=60%|source={{cite web |title=Re: Random Lockups with DR-DOS 7.03 |date=2004-06-17 |number=3 |author-first=Matthias R. |author-last=Paul |work=[[FidoNet]] conference: ALT_DOS |url=https://fidonet.ozzmosis.com/echomail.php/alt_dos/e812a919c10339d0.html |access-date=2019-04-28 |url-status=dead |archive-url=https://archive.today/20190428181749/https://fidonet.ozzmosis.com/echomail.php/alt_dos/e812a919c10339d0.html |archive-date=2019-04-28}} |quote=[...] all MS-DOS versions prior to Windows 95 [...] used a COM style COMMAND.COM file which has a special signature at the start of the file [...] queried by the MS-DOS BIOS before it loads the shell, but not by the DR-DOS BIOS [...] COMMAND.COM would [...] check that it is running on the "correct" DOS version, so if you would load their COMMAND.COM under DR-DOS, you would receive a "Bad version" error message and their COMMAND.COM would exit, so DR-DOS would [...] display an error message "Bad or missing command interpreter" (if DR-DOS was trying to load the SHELL= command processor after having finished CONFIG.SYS processing). In this case, you could enter the path to a valid DR-DOS COMMAND.COM (C:\DRDOS\COMMAND.COM) and everything was fine. Now, things have changed since MS-DOS 7.0 [...] COMMAND.COM has internally become an EXE style file, so there is no magic [...] signature [...] to check [...] thus no way for DR-DOS to rule out an incompatible COMMAND.COM. Further, their COMMAND.COM no longer does any version checks, but [...] does not work under DR-DOS [...] just crashes [...] the PC DOS COMMAND.COM works fine under DR-DOS [...] }}
* {{Cite book |author-last=Cooper |author-first=Jim |title=Special Edition Using MS-DOS 6.22 |edition=3 |date=2001 |publisher=[[Que Publishing]] |isbn=978-0-78972573-8}}
* {{Cite book |author-last=Wolverton |author-first=Van |title=MS-DOS Commands: Microsoft Quick Reference |edition=4th revised |date=1990 |publisher=[[Microsoft Press]] |isbn=978-1-55615289-4}}
* {{webarchive |url=https://archive.today/20190501023329/http://www.delorie.com/opendos/archives/browse.cgi?p=opendos/2004/06/17/06:23:16}}
* {{webarchive |url=https://archive.today/20190428182007/http://www.fybertech.com/misc/qwkview/qwkview.pl?conf=3010}}

==External links==
* {{Github|https://github.com/microsoft/MS-DOS/blob/main/v4.0/src/CMD/COMMAND/COMMAND1.ASM}} - Source code to COMMAND.COM version A067 released by Microsoft as part of MS-DOS 4.0
* {{GitHub|https://github.com/microsoft/MS-DOS/blob/master/v2.0/source/COMMAND.ASM}} – Source code to COMMAND.COM version 2.11 released by Microsoft as part of MS-DOS 2.0
* {{GitHub|https://github.com/microsoft/MS-DOS/blob/master/v1.25/source/COMMAND.ASM}} – Source code to COMMAND.COM version 1.17 released by Microsoft as part of MS-DOS 1.25
* [http://www.ibiblio.org/pub/micro/pc-stuff/freedos/files/distributions/1.2/repos/pkg-html/command.html FreeCom] – COMMAND.COM implementation of FreeDOS

{{Microsoft Windows components}}
{{Windows commands}}
{{DOS system files}}

[[Category:Command shells]]
[[Category:DOS command shells]]
[[Category:Windows command shells]]
[[Category:Scripting languages]]
[[Category:DOS files]]
[[Category:Windows files]]
[[Category:External DOS commands]]<!-- COMMAND.COM is external, COMMAND is internal -->
[[Category:MSX-DOS]]