<s>
Command	B-Device
Prompt	I-Device
,	O
also	O
known	O
as	O
cmd.exe	B-Device
or	O
cmd	B-Device
,	O
is	O
the	O
default	O
command-line	B-Application
interpreter	O
for	B-Language
the	O
OS/2	B-Application
,	O
eComStation	B-Device
,	O
ArcaOS	B-Device
,	O
Microsoft	B-Application
Windows	I-Application
(	O
Windows	B-Device
NT	I-Device
family	I-Device
and	O
Windows	B-Operating_System
CE	I-Operating_System
family	I-Operating_System
)	O
,	O
and	O
ReactOS	B-Application
operating	O
systems	O
.	O
</s>
<s>
On	O
Windows	B-Operating_System
CE	I-Operating_System
.NET	O
4.2	O
,	O
Windows	B-Operating_System
CE	I-Operating_System
5.0	I-Operating_System
and	O
Windows	B-Operating_System
Embedded	I-Operating_System
CE	I-Operating_System
6.0	I-Operating_System
it	O
is	O
referred	O
to	O
as	O
the	O
Command	B-Device
Processor	I-Device
Shell	I-Device
.	O
</s>
<s>
Its	O
implementations	O
differ	O
between	O
operating	O
systems	O
,	O
but	O
the	O
behavior	O
and	O
basic	O
set	O
of	O
commands	B-Application
are	O
consistent	O
.	O
</s>
<s>
is	O
the	O
counterpart	O
of	O
in	O
DOS	B-Device
and	O
Windows	O
9x	O
systems	O
,	O
and	O
analogous	O
to	O
the	O
Unix	B-Application
shells	I-Application
used	O
on	O
Unix-like	B-Operating_System
systems	I-Operating_System
.	O
</s>
<s>
The	O
initial	O
version	O
of	O
for	B-Language
Windows	B-Device
NT	I-Device
was	O
developed	O
by	O
Therese	O
Stowell	O
.	O
</s>
<s>
Windows	B-Operating_System
CE	I-Operating_System
2.11	O
was	O
the	O
first	O
embedded	O
Windows	O
release	O
to	O
support	O
a	O
console	O
and	O
a	O
Windows	B-Operating_System
CE	I-Operating_System
version	O
of	O
.	O
</s>
<s>
The	O
ReactOS	B-Application
implementation	O
of	O
is	O
derived	O
from	O
FreeCOM	B-Application
,	O
the	O
FreeDOS	B-Application
command	B-Application
line	I-Application
interpreter	O
.	O
</s>
<s>
interacts	O
with	O
the	O
user	O
through	O
a	O
command-line	B-Application
interface	I-Application
.	O
</s>
<s>
On	O
Windows	O
,	O
this	O
interface	O
is	O
implemented	O
through	O
the	O
Win32	B-Application
console	I-Application
.	O
</s>
<s>
For	B-Language
example	O
,	O
on	O
OS/2	B-Application
and	O
Windows	O
,	O
it	O
can	O
use	O
real	O
pipes	B-Operating_System
in	O
command	O
pipelines	B-Operating_System
,	O
allowing	O
both	O
sides	O
of	O
the	O
pipeline	B-Operating_System
to	O
run	O
concurrently	O
.	O
</s>
<s>
Multiple	O
commands	B-Application
can	O
be	O
processed	O
in	O
a	O
single	O
command	B-Application
line	I-Application
using	O
the	O
command	O
separator	O
.	O
</s>
<s>
When	O
using	O
this	O
separator	O
in	O
the	O
Windows	O
,	O
each	O
command	O
must	O
complete	O
successfully	O
for	B-Language
the	O
following	O
commands	B-Application
to	O
execute	O
.	O
</s>
<s>
For	B-Language
example	O
:	O
</s>
<s>
To	O
process	O
subsequent	O
commands	B-Application
even	O
if	O
the	O
previous	O
command	O
produces	O
an	O
error	O
,	O
the	O
command	O
separator	O
should	O
be	O
used	O
.	O
</s>
<s>
For	B-Language
example	O
:	O
</s>
<s>
On	O
Windows	B-Application
XP	I-Application
or	O
later	O
,	O
the	O
maximum	O
length	O
of	O
the	O
string	O
that	O
can	O
be	O
used	O
at	O
the	O
command	B-Device
prompt	I-Device
is	O
8191	O
characters	O
.	O
</s>
<s>
On	O
earlier	O
versions	O
,	O
such	O
as	O
Windows	B-Application
2000	I-Application
or	O
Windows	B-Device
NT	I-Device
4.0	I-Device
,	O
the	O
maximum	O
length	O
of	O
the	O
string	O
is	O
2047	O
characters	O
.	O
</s>
<s>
This	O
limit	O
includes	O
the	O
command	B-Application
line	I-Application
,	O
individual	O
environment	O
variables	O
that	O
are	O
inherited	O
by	O
other	O
processes	B-Operating_System
,	O
and	O
all	O
environment	O
variable	O
expansions	O
.	O
</s>
<s>
Quotation	O
marks	O
are	O
required	O
for	B-Language
the	O
following	O
special	O
characters	O
:	O
</s>
<s>
The	O
following	O
is	O
a	O
list	O
of	O
the	O
Microsoft	B-Application
OS/2	I-Application
internal	O
commands	B-Application
:	O
</s>
<s>
The	O
following	O
list	O
of	O
internal	O
commands	B-Application
is	O
supported	O
by	O
on	O
Windows	B-Device
NT	I-Device
and	O
later	O
:	O
</s>
<s>
The	O
following	O
list	O
of	O
commands	B-Application
is	O
supported	O
by	O
on	O
Windows	B-Operating_System
CE	I-Operating_System
.NET	O
4.2	O
,	O
Windows	B-Operating_System
CE	I-Operating_System
5.0	I-Operating_System
and	O
Windows	B-Operating_System
Embedded	I-Operating_System
CE	I-Operating_System
6.0	I-Operating_System
:	O
</s>
<s>
The	O
ReactOS	B-Application
implementation	O
includes	O
the	O
following	O
internal	O
commands	B-Application
:	O
</s>
<s>
More	O
detailed	O
error	O
messages	O
than	O
the	O
blanket	O
"	O
Bad	B-Application
command	I-Application
or	I-Application
file	I-Application
name	I-Application
"	O
(	O
in	O
the	O
case	O
of	O
malformed	O
commands	B-Application
)	O
of	O
.	O
</s>
<s>
In	O
OS/2	B-Application
,	O
errors	O
are	O
reported	O
in	O
the	O
chosen	O
language	O
of	O
the	O
system	O
,	O
their	O
text	O
being	O
taken	O
from	O
the	O
system	O
message	O
files	O
.	O
</s>
<s>
Supports	O
using	O
of	O
arrow	O
keys	O
to	O
scroll	O
through	O
command	O
history	B-Device
.	O
</s>
<s>
(	O
Under	O
DOS	B-Device
this	O
function	O
was	O
only	O
available	O
under	O
DR	B-Application
DOS	I-Application
(	O
through	O
HISTORY	B-Device
)	O
and	O
later	O
via	O
an	O
external	O
component	O
called	O
.	O
)	O
</s>
<s>
Adds	O
rotating	O
command-line	B-Application
completion	O
for	B-Language
file	O
and	O
folder	O
paths	O
,	O
where	O
the	O
user	O
can	O
cycle	O
through	O
results	O
for	B-Language
the	O
prefix	O
using	O
the	O
,	O
and	O
for	B-Language
reverse	O
direction	O
.	O
</s>
<s>
Treats	O
the	O
caret	O
character	O
(	O
)	O
as	O
the	O
escape	B-Algorithm
character	I-Algorithm
;	O
the	O
character	O
following	O
it	O
is	O
to	O
be	O
taken	O
literally	O
.	O
</s>
<s>
""	O
,	O
""	O
and	O
"	O
|	O
"	O
)	O
that	O
are	O
meant	O
to	O
alter	O
the	O
behavior	O
of	O
the	O
command	B-Application
line	I-Application
processor	O
.	O
</s>
<s>
The	O
caret	O
character	O
forces	O
the	O
command	B-Application
line	I-Application
processor	O
to	O
interpret	O
them	O
literally	O
.	O
</s>
<s>
Supports	O
delayed	O
variable	O
expansion	O
with	O
,	O
allowing	O
values	O
of	O
variables	O
to	O
be	O
calculated	O
at	O
runtime	O
instead	O
of	O
during	O
parsing	O
of	O
script	O
before	O
execution	O
(	O
Windows	B-Application
2000	I-Application
and	O
later	O
)	O
,	O
fixing	O
DOS	B-Device
idioms	O
that	O
made	O
using	O
control	O
structures	O
hard	O
and	O
complex	O
.	O
</s>
<s>
Internal	O
commands	B-Application
have	O
also	O
been	O
improved	O
:	O
</s>
<s>
and	O
commands	B-Application
limit	O
the	O
scope	O
of	O
changes	O
to	O
the	O
environment	O
.	O
</s>
<s>
Changes	O
made	O
to	O
the	O
command	B-Application
line	I-Application
environment	I-Application
after	O
commands	B-Application
are	O
local	O
to	O
the	O
batch	O
file	O
.	O
</s>
<s>
File	O
name	O
parser	O
extensions	O
to	O
the	O
command	O
are	O
comparable	O
with	O
C	B-Operating_System
shell	I-Operating_System
.	O
</s>
<s>
The	O
new	O
and	O
commands	B-Application
provide	O
access	O
past	O
navigated	O
paths	O
similar	O
to	O
"	O
forward	O
"	O
and	O
"	O
back	O
"	O
buttons	O
in	O
a	O
web	O
browser	O
or	O
File	B-Protocol
Explorer	I-Protocol
.	O
</s>
<s>
(	O
This	O
was	O
available	O
in	O
DR-DOS	B-Application
,	O
but	O
not	O
in	O
PC	O
DOS	B-Device
or	O
MS-DOS	B-Application
.	O
)	O
</s>
