Editing CLS (command)

{{Infobox software
| name = cls
| logo = 
| screenshot = 
| screenshot size = 
| caption = 
| developer = [[Digital Equipment Corporation|DEC]], [[Microsoft]], [[IBM]], [[The Software Link|TSL]], [[Digital Research|DR]], [[Novell]], [[Toshiba]], ReactOS Contributors
| released = 
| latest release version = 
| latest release date = 
| operating system = [[RT-11]], [[DOS]], [[MSX-DOS]], [[FlexOS]], [[PC-MOS]], [[SISNE plus]], [[OS/2]], [[Microsoft Windows|Windows]], [[ReactOS]], [[SymbOS]], DexOS
| platform = [[Cross-platform]]
| genre = [[Command (computing)|Command]]
| license = PC-MOS: [[GPL v3]]<br />ReactOS: [[GPL v2]]
| website = 
}}
In [[computing]], '''<code>CLS</code>''' (for '''cl'''ear '''s'''creen) is a [[command (computing)|command]] used by the [[command-line interpreter]]s <code>[[COMMAND.COM]]</code> and <code>[[cmd.exe]]</code> on [[DOS]], [[Digital Research]] [[FlexOS]],<ref>http://www.bitsavers.org/pdf/digitalResearch/flexos/1073-2003_FlexOS_Users_Guide_V1.3_Nov86.pdf {{Webarchive|url=https://web.archive.org/web/20190925131719/http://bitsavers.org/pdf/digitalResearch/flexos/1073-2003_FlexOS_Users_Guide_V1.3_Nov86.pdf |date=2019-09-25 }} {{Bare URL PDF|date=March 2022}}</ref> [[IBM]] [[OS/2]],<ref>{{Cite web |url=http://www.jatomes.com/Help/Os2Cmd.php#CLS |title=JaTomes Help - OS/2 Commands |access-date=2019-07-06 |archive-date=2019-04-14 |archive-url=https://web.archive.org/web/20190414130029/http://www.jatomes.com/Help/Os2Cmd.php#CLS |url-status=dead }}</ref> [[Microsoft Windows]]<ref>[https://technet.microsoft.com/en-us/library/bb490879.aspx Microsoft TechNet Cls article]</ref> and [[ReactOS]] [[operating systems]] to clear the screen or [[Terminal emulator|console window]] of commands and any output generated by them. It does not clear the user's [[command history|history of commands]], however.
The command is also available in the [[Digital Equipment Corporation|DEC]] [[RT-11]] operating system, in the [[open-source software|open-source]] [[MS-DOS]] [[emulator]] [[DOSBox]] and in the [[Unified Extensible Firmware Interface|EFI shell]].<ref name="EFI-Shells-and-Scripting">{{cite web
 | url = http://software.intel.com/en-us/articles/efi-shells-and-scripting/
 | title = EFI Shells and Scripting
 | publisher = [[Intel]]
 | access-date = 2013-09-25
}}</ref> In other environments, such as [[Linux]] and [[Unix]], the same functionality is provided by the <code>[[clear (Unix)|clear]]</code> command.

==History==
The command is available in [[MS-DOS]] versions 2 (1983) and later.<ref name="RUNNINGMSDOS">{{Cite book|author-last=Wolverton|author-first=Van|title=Running MS-DOS Version 6.22 (20th Anniversary Edition), 6th Revised edition|date=2003|publisher=[[Microsoft Press]]|isbn=0-7356-1812-7}}</ref> While the ultimate origins of using the three-character string <code>CLS</code> as the command to clear the screen likely predate [[Microsoft]]'s use, this command was present before its MS-DOS usage, in the embedded ROM [[BASIC]] dialects Microsoft wrote for early [[8-bit]] [[microcomputer]]s (such as [[TRS-80]] [[Color BASIC]]), where it served the same purpose. The MS-DOS dialects of BASIC written by Microsoft, [[BASICA]] and [[GW-BASIC]], also have the <code>CLS</code> command as a BASIC keyword  - as do various non-Microsoft implementations of BASIC such as [[Sinclair BASIC]] (1980), or [[BBC BASIC]] found on the [[BBC Micro]] computers (1981). The <code>CLS</code> command is also present in BASIC versions for Microsoft Windows, however this generally clears text printed on the form, rather than the whole window or controls on the form.

The command <code>CLS</code> has appeared as a clear screen command in many other BASIC dialects and command line interpreters, because of its familiarity through being included in MS-DOS.

[[The Software Link]]'s [[PC-MOS]] includes an implementation of <code>CLS</code>.<ref>[https://github.com/roelandjansen/pcmos386v501/blob/master/DOCS/v4/PCMOSv4UserManual.pdf PC-MOS User Guide]</ref> Like the rest of the operating system, it is licensed under the [[GPL v3]].<ref>{{cite web|url=https://github.com/roelandjansen/pcmos386v501|title=pcmos386v501: PC-MOS/386 v5.01 final release including cdrom driver sources|first=Roeland|last=Jansen|date=8 February 2018|via=GitHub}}</ref>

[[DR DOS]] also includes an implementation of the {{code|CLS}} command.<ref name="drdos6userguide">{{Cite web |url=https://www.4corn.co.uk/archive/docs/DR%20DOS%206.0%20User%20Guide-opt.pdf |title=DR DOS 6.0 User Guide Optimisation and Configuration Tips |access-date=2019-08-13 |archive-url=https://web.archive.org/web/20190930135943/http://www.4corn.co.uk/archive/docs/DR%20DOS%206.0%20User%20Guide-opt.pdf |archive-date=2019-09-30 |url-status=dead }}</ref>

==See also==
*[[CLS (CONFIG.SYS directive)]]
*[[List of DOS commands]]

==References==
{{Reflist}}

==Further reading==
*{{Cite book|author-last=Wolverton|author-first=Van|title=MS-DOS Commands: Microsoft Quick Reference, 4th Revised edition|url=https://archive.org/details/msdos00wolv|url-access=registration|date=1990|publisher=[[Microsoft Press]]|isbn=978-1556152894}}
*{{Cite book|author1=Kathy Ivens|author2=Brian Proffit|year=1993|title=OS/2 Inside & Out|publisher=[[Osborne McGraw-Hill]]|isbn=978-0078818714}}
*{{Cite book|first=Æleen|last=Frisch|year=2001|title=Windows 2000 Commands Pocket Reference|publisher=[[O'Reilly Media|O'Reilly]]|isbn=978-0-596-00148-3}}

==External links==
{{Wikibooks|Guide to Windows Commands}}
*[https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/cls cls | Microsoft Docs]

{{Windows commands}}

[[Category:Internal DOS commands]]
[[Category:MSX-DOS commands]]
[[Category:OS/2 commands]]
[[Category:ReactOS commands]]
[[Category:Windows commands]]