The command is available in
MS-DOS versions 2 (1983) and later. While the ultimate origins of using the three-character string CLS 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 microcomputers (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 CLS 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 CLS 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 CLS 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 CLS. Like the rest of the operating system, it is licensed under the
GPL v3.
DR DOS also includes an implementation of the command. ==See also==