<s>
In	O
computing	O
,	O
CLS	B-Device
(	O
for	O
clear	B-Device
screen	I-Device
)	O
is	O
a	O
command	B-Application
used	O
by	O
the	O
command-line	O
interpreters	O
COMMAND.COM	B-Operating_System
and	O
cmd.exe	B-Device
on	O
DOS	B-Device
,	O
Digital	B-Operating_System
Research	I-Operating_System
FlexOS	I-Operating_System
,	O
IBM	B-Application
OS/2	I-Application
,	O
Microsoft	B-Application
Windows	I-Application
and	O
ReactOS	B-Application
operating	B-General_Concept
systems	I-General_Concept
to	O
clear	B-Device
the	O
screen	O
or	O
console	B-Application
window	I-Application
of	O
commands	O
and	O
any	O
output	O
generated	O
by	O
them	O
.	O
</s>
<s>
It	O
does	O
not	O
clear	B-Device
the	O
user	O
's	O
history	B-Application
of	I-Application
commands	I-Application
,	O
however	O
.	O
</s>
<s>
The	O
command	B-Application
is	O
also	O
available	O
in	O
the	O
DEC	O
RT-11	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
,	O
in	O
the	O
open-source	B-Application
MS-DOS	B-Application
emulator	B-Application
DOSBox	B-Application
and	O
in	O
the	O
EFI	B-Architecture
shell	I-Architecture
.	O
</s>
<s>
In	O
other	O
environments	O
,	O
such	O
as	O
Linux	B-Application
and	O
Unix	B-Application
,	O
the	O
same	O
functionality	O
is	O
provided	O
by	O
the	O
clear	B-Device
command	B-Application
.	O
</s>
<s>
The	O
command	B-Application
is	O
available	O
in	O
MS-DOS	B-Application
versions	O
2	O
and	O
later	O
.	O
</s>
<s>
While	O
the	O
ultimate	O
origins	O
of	O
using	O
the	O
three-character	O
string	O
CLS	B-Device
as	O
the	O
command	B-Application
to	O
clear	B-Device
the	O
screen	O
likely	O
predate	O
Microsoft	O
's	O
use	O
,	O
this	O
command	B-Application
was	O
present	O
before	O
its	O
MS-DOS	B-Application
usage	O
,	O
in	O
the	O
embedded	O
ROM	O
BASIC	O
dialects	O
Microsoft	O
wrote	O
for	O
early	O
8-bit	O
microcomputers	B-Architecture
(	O
such	O
as	O
TRS-80	B-Device
Color	B-Language
BASIC	I-Language
)	O
,	O
where	O
it	O
served	O
the	O
same	O
purpose	O
.	O
</s>
<s>
The	O
MS-DOS	B-Application
dialects	O
of	O
BASIC	O
written	O
by	O
Microsoft	O
,	O
BASICA	O
and	O
GW-BASIC	B-Language
,	O
also	O
have	O
the	O
CLS	B-Device
command	B-Application
as	O
a	O
BASIC	O
keyword	O
-	O
as	O
do	O
various	O
non-Microsoft	O
implementations	O
of	O
BASIC	O
such	O
as	O
BBC	B-Language
BASIC	I-Language
found	O
on	O
the	O
BBC	B-Device
Micro	I-Device
computers	O
.	O
</s>
<s>
The	O
CLS	B-Device
command	B-Application
is	O
also	O
present	O
in	O
BASIC	O
versions	O
for	O
Microsoft	B-Application
Windows	I-Application
,	O
however	O
this	O
generally	O
clears	O
text	O
printed	O
on	O
the	O
form	O
,	O
rather	O
than	O
the	O
whole	O
window	O
or	O
controls	O
on	O
the	O
form	O
.	O
</s>
<s>
The	O
command	B-Application
CLS	B-Device
has	O
appeared	O
as	O
a	O
clear	B-Device
screen	I-Device
command	B-Application
in	O
many	O
other	O
BASIC	O
dialects	O
and	O
command	B-Application
line	O
interpreters	O
,	O
because	O
of	O
its	O
familiarity	O
through	O
being	O
included	O
in	O
MS-DOS	B-Application
.	O
</s>
<s>
The	O
Software	O
Link	O
's	O
PC-MOS	O
includes	O
an	O
implementation	O
of	O
CLS	B-Device
.	O
</s>
<s>
Like	O
the	O
rest	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
,	O
it	O
is	O
licensed	O
under	O
the	O
GPL	O
v3	O
.	O
</s>
<s>
DR	O
DOS	B-Device
6.0	O
also	O
includes	O
an	O
implementation	O
of	O
the	O
command	B-Application
.	O
</s>
