<s>
An	O
environment	O
variable	O
is	O
a	O
dynamic-named	B-Application
value	O
that	O
can	O
affect	O
the	O
way	O
running	O
processes	B-Operating_System
will	O
behave	O
on	O
a	O
computer	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
running	O
process	O
can	O
query	O
the	O
value	O
of	O
the	O
TEMP	O
environment	O
variable	O
to	O
discover	O
a	O
suitable	O
location	O
to	O
store	O
temporary	B-Application
files	I-Application
,	O
or	O
the	O
HOME	O
or	O
USERPROFILE	O
variable	O
to	O
find	O
the	O
directory	B-Architecture
structure	I-Architecture
owned	O
by	O
the	O
user	O
running	O
the	O
process	O
.	O
</s>
<s>
They	O
were	O
introduced	O
in	O
their	O
modern	O
form	O
in	O
1979	O
with	O
Version	B-Operating_System
7	I-Operating_System
Unix	I-Operating_System
,	O
so	O
are	O
included	O
in	O
all	O
Unix	B-Application
operating	I-Application
system	I-Application
flavors	O
and	O
variants	O
from	O
that	O
point	O
onward	O
including	O
Linux	B-Application
and	O
macOS	B-Application
.	O
</s>
<s>
From	O
PC	O
DOS	B-Device
2.0	O
in	O
1982	O
,	O
all	O
succeeding	O
Microsoft	O
operating	B-General_Concept
systems	I-General_Concept
,	O
including	O
Microsoft	B-Application
Windows	I-Application
,	O
and	O
OS/2	B-Application
also	O
have	O
included	O
them	O
as	O
a	O
feature	O
,	O
although	O
with	O
somewhat	O
different	O
syntax	O
,	O
usage	O
and	O
standard	O
variable	O
names	O
.	O
</s>
<s>
In	O
all	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
as	O
well	O
as	O
on	O
Windows	B-Application
,	O
each	O
process	O
has	O
its	O
own	O
separate	O
set	B-Device
of	O
environment	O
variables	O
.	O
</s>
<s>
By	O
default	O
,	O
when	O
a	O
process	O
is	O
created	O
,	O
it	O
inherits	O
a	O
duplicate	O
run-time	B-Device
environment	I-Device
of	O
its	O
parent	O
process	O
,	O
except	O
for	O
explicit	O
changes	O
made	O
by	O
the	O
parent	O
when	O
it	O
creates	O
the	O
child	O
.	O
</s>
<s>
At	O
the	O
API	B-Application
level	O
,	O
these	O
changes	O
must	O
be	O
done	O
between	O
running	O
fork	B-Language
and	O
exec	B-Operating_System
.	O
</s>
<s>
Alternatively	O
,	O
from	O
command	O
shells	O
such	O
as	O
bash	B-Operating_System
,	O
a	O
user	O
can	O
change	O
environment	O
variables	O
for	O
a	O
particular	O
command	O
invocation	O
by	O
indirectly	O
invoking	O
it	O
via	O
env	B-Device
or	O
using	O
the	O
ENVIRONMENT_VARIABLE	O
=	O
VALUE	O
<command>	O
notation	O
.	O
</s>
<s>
Shell	B-Language
scripts	I-Language
and	O
batch	O
files	O
use	O
environment	O
variables	O
to	O
communicate	O
data	O
and	O
preferences	O
to	O
child	O
processes	B-Operating_System
.	O
</s>
<s>
They	O
can	O
also	O
be	O
used	O
to	O
store	O
temporary	O
values	O
for	O
reference	O
later	O
in	O
a	O
shell	B-Language
script	I-Language
.	O
</s>
<s>
However	O
,	O
in	O
Unix	B-Application
,	O
non-exported	O
variables	O
are	O
preferred	O
for	O
this	O
as	O
they	O
do	O
n't	O
leak	O
outside	O
the	O
process	O
.	O
</s>
<s>
In	O
Unix	B-Application
,	O
an	O
environment	O
variable	O
that	O
is	O
changed	O
in	O
a	O
script	O
or	O
compiled	O
program	O
will	O
only	O
affect	O
that	O
process	O
and	O
possibly	O
child	O
processes	B-Operating_System
.	O
</s>
<s>
The	O
parent	O
process	O
and	O
any	O
unrelated	O
processes	B-Operating_System
will	O
not	O
be	O
affected	O
.	O
</s>
<s>
Similarly	O
,	O
changing	O
or	O
removing	O
a	O
variable	O
's	O
value	O
inside	O
a	O
DOS	B-Device
or	O
Windows	B-Application
batch	O
file	O
will	O
change	O
the	O
variable	O
for	O
the	O
duration	O
of	O
COMMAND.COMor	O
CMD.EXE	B-Device
'	O
s	O
existence	O
,	O
respectively	O
.	O
</s>
<s>
In	O
Unix	B-Application
,	O
the	O
environment	O
variables	O
are	O
normally	O
initialized	O
during	O
system	O
startup	O
by	O
the	O
system	O
init	B-Operating_System
startup	O
scripts	O
,	O
and	O
hence	O
inherited	O
by	O
all	O
other	O
processes	B-Operating_System
in	O
the	O
system	O
.	O
</s>
<s>
Users	O
can	O
,	O
and	O
often	O
do	O
,	O
augment	O
them	O
in	O
the	O
profile	O
script	O
for	O
the	O
command	O
shell	B-Device
they	O
are	O
using	O
.	O
</s>
<s>
In	O
Microsoft	B-Application
Windows	I-Application
,	O
each	O
environment	O
variable	O
's	O
default	O
value	O
is	O
stored	O
in	O
the	O
Windows	B-Protocol
Registry	I-Protocol
or	O
set	B-Device
in	O
the	O
AUTOEXEC.BAT	O
file	O
.	O
</s>
<s>
On	O
Unix	B-Application
,	O
a	O
setuid	O
program	O
is	O
given	O
an	O
environment	O
chosen	O
by	O
its	O
caller	O
,	O
but	O
it	O
runs	O
with	O
different	O
authority	O
from	O
its	O
caller	O
.	O
</s>
<s>
The	O
dynamic	B-Application
linker	I-Application
will	O
usually	O
load	O
code	O
from	O
locations	O
specified	O
by	O
the	O
environment	O
variables	O
$LD_LIBRARY_PATH	O
and	O
$LD_PRELOAD	O
and	O
run	O
it	O
with	O
the	O
process	O
's	O
authority	O
.	O
</s>
<s>
For	O
this	O
reason	O
,	O
libc	B-Language
unsets	O
these	O
environment	O
variables	O
at	O
startup	O
in	O
a	O
setuid	O
process	O
.	O
</s>
<s>
setuid	O
programs	O
usually	O
unset	O
unknown	O
environment	O
variables	O
and	O
check	O
others	O
or	O
set	B-Device
them	O
to	O
reasonable	O
values	O
.	O
</s>
<s>
In	O
general	O
,	O
the	O
collection	O
of	O
environment	O
variables	O
function	O
as	O
an	O
associative	B-Application
array	I-Application
where	O
both	O
the	O
keys	O
and	O
values	O
are	O
strings	O
.	O
</s>
<s>
When	O
data	O
structures	O
such	O
as	O
lists	O
need	O
to	O
be	O
represented	O
,	O
it	O
is	O
common	O
to	O
use	O
a	O
colon	O
(	O
common	O
on	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
)	O
or	O
semicolon-deliminated	O
(	O
common	O
on	O
Windows	B-Application
and	O
DOS	B-Device
)	O
list	O
.	O
</s>
<s>
The	O
variables	O
can	O
be	O
used	O
both	O
in	O
scripts	O
and	O
on	O
the	O
command	B-Application
line	I-Application
.	O
</s>
<s>
Environment-variable	O
names	O
are	O
case	O
sensitive	O
on	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
but	O
not	O
on	O
DOS	B-Device
,	O
OS/2	B-Application
,	O
and	O
Windows	B-Application
.	O
</s>
<s>
In	O
most	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
command-line	B-Application
shells	O
,	O
an	O
environment	O
variable	O
's	O
value	O
is	O
retrieved	O
by	O
placing	O
a	O
$	O
sign	O
before	O
the	O
variable	O
's	O
name	O
.	O
</s>
<s>
To	O
display	O
the	O
user	O
home	B-Application
directory	I-Application
,	O
the	O
user	O
may	O
type	B-Device
:	O
</s>
<s>
If	O
xyz	O
needed	O
to	O
be	O
appended	O
to	O
the	O
value	O
of	O
the	O
HOME	O
variable	O
,	O
one	O
might	O
type	B-Device
:	O
</s>
<s>
In	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
the	O
names	O
of	O
environment	O
variables	O
are	O
case-sensitive	O
.	O
</s>
<s>
The	O
command	O
env	B-Device
displays	O
all	O
environment	O
variables	O
and	O
their	O
values	O
.	O
</s>
<s>
In	O
DOS	B-Device
,	O
OS/2	B-Application
and	O
Windows	B-Application
command-line	B-Application
interpreters	O
such	O
as	O
COMMAND.COM	B-Operating_System
and	O
CMD.EXE	B-Device
,	O
an	O
environment	O
variable	O
is	O
retrieved	O
by	O
placing	O
a	O
%	O
sign	O
before	O
and	O
after	O
it	O
.	O
</s>
<s>
In	O
DOS	B-Device
,	O
OS/2	B-Application
and	O
Windows	B-Application
command-line	B-Application
interpreters	O
as	O
well	O
as	O
their	O
API	B-Application
,	O
upper	O
or	O
lower	O
case	O
is	O
not	O
distinguished	O
for	O
environment	O
variable	O
names	O
.	O
</s>
<s>
The	O
environment	O
variable	O
named	O
HOMEDRIVE	O
contains	O
the	O
drive	O
letter	O
(	O
plus	O
its	O
trailing	O
:	O
colon	O
)	O
of	O
the	O
user	O
's	O
home	B-Application
directory	I-Application
,	O
whilst	O
HOMEPATH	O
contains	O
the	O
full	O
path	B-Application
of	O
the	O
user	O
's	O
home	B-Application
directory	I-Application
within	O
that	O
drive	O
.	O
</s>
<s>
So	O
to	O
see	O
the	O
home	O
drive	O
and	O
path	B-Application
,	O
the	O
user	O
may	O
type	B-Device
this	O
:	O
</s>
<s>
The	O
command	O
SET	B-Device
(	O
with	O
no	O
arguments	O
)	O
displays	O
all	O
environment	O
variables	O
and	O
their	O
values	O
.	O
</s>
<s>
set	B-Device
can	O
also	O
be	O
used	O
to	O
print	O
all	O
variables	O
whose	O
name	O
begins	O
with	O
a	O
given	O
prefix	O
by	O
giving	O
the	O
prefix	O
as	O
the	O
sole	O
argument	O
to	O
the	O
command	O
.	O
</s>
<s>
In	O
Windows	B-Application
PowerShell	I-Application
,	O
the	O
user	O
may	O
type	B-Device
any	O
of	O
the	O
following	O
:	O
</s>
<s>
In	O
PowerShell	B-Application
,	O
upper	O
or	O
lower	O
case	O
is	O
not	O
distinguished	O
for	O
environment	O
variable	O
names	O
.	O
</s>
<s>
The	O
commands	O
env	B-Device
and	O
set	B-Device
can	O
be	O
used	O
to	O
set	B-Device
environment	O
variables	O
and	O
are	O
often	O
incorporated	O
directly	O
into	O
the	O
shell	B-Device
.	O
</s>
<s>
The	O
following	O
commands	O
can	O
also	O
be	O
used	O
,	O
but	O
are	O
often	O
dependent	O
on	O
a	O
certain	O
shell	B-Device
.	O
</s>
<s>
Environment	O
variables	O
are	O
local	O
to	O
the	O
process	O
in	O
which	O
they	O
were	O
set	B-Device
.	O
</s>
<s>
If	O
two	O
shell	B-Device
processes	B-Operating_System
are	O
spawned	O
and	O
the	O
value	O
of	O
an	O
environment	O
variable	O
is	O
changed	O
in	O
one	O
,	O
that	O
change	O
will	O
not	O
be	O
seen	O
by	O
the	O
other	O
.	O
</s>
<s>
When	O
a	O
child	B-Operating_System
process	I-Operating_System
is	O
created	O
,	O
it	O
inherits	O
all	O
the	O
environment	O
variables	O
and	O
their	O
values	O
from	O
the	O
parent	O
process	O
.	O
</s>
<s>
Usually	O
,	O
when	O
a	O
program	O
calls	O
another	O
program	O
,	O
it	O
first	O
creates	O
a	O
child	B-Operating_System
process	I-Operating_System
by	O
forking	O
,	O
then	O
the	O
child	O
adjusts	O
the	O
environment	O
as	O
needed	O
and	O
lastly	O
the	O
child	O
replaces	B-Operating_System
itself	O
with	O
the	O
program	O
to	O
be	O
called	O
.	O
</s>
<s>
In	O
Unix	B-Application
shells	I-Application
,	O
variables	O
may	O
be	O
assigned	O
without	O
the	O
export	O
keyword	O
.	O
</s>
<s>
Variables	O
defined	O
in	O
this	O
way	O
are	O
displayed	O
by	O
the	O
set	B-Device
command	O
,	O
but	O
are	O
not	O
true	O
environment	O
variables	O
,	O
as	O
they	O
are	O
stored	O
only	O
by	O
the	O
shell	B-Device
and	O
are	O
unknown	O
to	O
all	O
other	O
processes	B-Operating_System
.	O
</s>
<s>
The	O
printenv	O
command	O
will	O
not	O
display	O
them	O
,	O
and	O
child	O
processes	B-Operating_System
do	O
not	O
inherit	O
them	O
.	O
</s>
<s>
The	O
prefix	O
syntax	O
exports	O
a	O
"	O
true	O
"	O
environment	O
variable	O
to	O
a	O
child	B-Operating_System
process	I-Operating_System
without	O
affecting	O
the	O
current	O
process	O
:	O
</s>
<s>
unset	O
is	O
a	O
builtin	O
command	O
implemented	O
by	O
both	O
the	B-Device
Bourne	I-Device
shell	I-Device
family	O
(	O
sh	O
,	O
ksh	B-Language
,	O
bash	B-Operating_System
,	O
etc	O
.	O
)	O
</s>
<s>
and	O
the	O
C	B-Operating_System
shell	I-Operating_System
family	O
(	O
csh	B-Operating_System
,	O
tcsh	O
,	O
etc	O
.	O
)	O
</s>
<s>
of	O
Unix	B-Application
command	I-Application
line	O
shells	O
.	O
</s>
<s>
It	O
unsets	O
a	O
shell	B-Device
variable	O
,	O
removing	O
it	O
from	O
memory	O
and	O
the	O
shell	B-Device
's	O
exported	O
environment	O
.	O
</s>
<s>
It	O
is	O
implemented	O
as	O
a	O
shell	B-Device
builtin	O
,	O
because	O
it	O
directly	O
manipulates	O
the	O
internals	O
of	O
the	O
shell	B-Device
.	O
</s>
<s>
Read-only	O
shell	B-Device
variables	O
cannot	O
be	O
unset	O
.	O
</s>
<s>
In	O
DOS	B-Device
,	O
OS/2	B-Application
and	O
Windows	B-Application
command-line	B-Application
interpreters	O
such	O
as	O
COMMAND.COM	B-Operating_System
and	O
CMD.EXE	B-Device
,	O
the	O
SET	B-Device
command	O
is	O
used	O
to	O
assign	O
environment	O
variables	O
and	O
values	O
using	O
the	O
following	O
arguments	O
:	O
</s>
<s>
The	O
SET	B-Device
command	O
without	O
any	O
arguments	O
displays	O
all	O
environment	O
variables	O
along	O
with	O
their	O
values	O
;	O
SET	B-Device
"	O
"	O
,	O
zero	O
or	O
more	O
spaces	O
,	O
will	O
include	O
internal	O
variables	O
too	O
.	O
</s>
<s>
In	O
CMD.EXE	B-Device
,	O
it	O
is	O
possible	O
to	O
assign	O
local	O
variables	O
that	O
will	O
not	O
be	O
global	O
using	O
the	O
SETLOCAL	O
command	O
and	O
ENDLOCAL	O
to	O
restore	O
the	O
environment	O
.	O
</s>
<s>
to	O
display	O
the	O
internal	O
documentation	B-Protocol
,	O
or	O
use	O
the	O
viewer	O
help	O
:	O
</s>
<s>
In	O
PowerShell	B-Application
,	O
the	O
assignment	O
follows	O
a	O
syntax	O
similar	O
to	O
Unix	B-Application
:	O
</s>
<s>
PATH	B-Application
:	O
a	O
list	O
of	O
directory	O
paths	O
.	O
</s>
<s>
When	O
the	O
user	O
types	O
a	O
command	O
without	O
providing	O
the	O
full	O
path	B-Application
,	O
this	O
list	O
is	O
checked	O
to	O
see	O
whether	O
it	O
contains	O
a	O
path	B-Application
that	O
leads	O
to	O
the	O
command	O
.	O
</s>
<s>
HOME	O
(	O
Unix-like	B-Operating_System
)	O
and	O
USERPROFILE	O
(	O
Microsoft	B-Application
Windows	I-Application
)	O
:	O
indicate	O
where	O
a	O
user	O
's	O
home	B-Application
directory	I-Application
is	O
located	O
in	O
the	O
file	B-Application
system	I-Application
.	O
</s>
<s>
HOME/{.AppName}	O
(	O
Unix-like	B-Operating_System
)	O
and	O
APPDATA\{DeveloperName\AppName}	O
(	O
Microsoft	B-Application
Windows	I-Application
)	O
:	O
for	O
storing	O
application	O
settings	O
.	O
</s>
<s>
Many	O
applications	O
incorrectly	O
use	O
USERPROFILE	O
for	O
application	O
settings	O
in	O
Windows	B-Application
:	O
USERPROFILE	O
should	O
only	O
be	O
used	O
in	O
dialogs	O
that	O
allow	O
user	O
to	O
choose	O
between	O
paths	O
like	O
Documents/Pictures/Downloads/Music	O
;	O
for	O
programmatic	O
purposes	O
,	O
APPDATA	O
(	O
for	O
roaming	O
application	O
settings	O
shared	O
across	O
multiple	O
devices	O
)	O
,	O
LOCALAPPDATA	O
(	O
for	O
local	O
application	O
settings	O
)	O
or	O
PROGRAMDATA	O
(	O
for	O
application	O
settings	O
shared	O
between	O
multiple	O
OS	O
users	O
)	O
should	O
be	O
used	O
.	O
</s>
<s>
TERM	O
(	O
Unix-like	B-Operating_System
)	O
:	O
specifies	O
the	O
type	B-Device
of	O
computer	B-General_Concept
terminal	I-General_Concept
or	O
terminal	B-Application
emulator	I-Application
being	O
used	O
(	O
e.g.	O
,	O
vt100	B-Device
or	O
dumb	O
)	O
.	O
</s>
<s>
PS1	O
(	O
Unix-like	B-Operating_System
)	O
:	O
specifies	O
how	O
the	O
prompt	O
is	O
displayed	O
in	O
the	B-Device
Bourne	I-Device
shell	I-Device
and	O
variants	O
.	O
</s>
<s>
MAIL	O
(	O
Unix-like	B-Operating_System
)	O
:	O
used	O
to	O
indicate	O
where	O
a	O
user	O
's	O
mail	O
is	O
to	O
be	O
found	O
.	O
</s>
<s>
TEMP	O
:	O
location	O
where	O
processes	B-Operating_System
can	O
store	O
temporary	B-Application
files	I-Application
.	O
</s>
<s>
$PATH	B-Application
Contains	O
a	O
colon-separated	O
list	O
of	O
directories	O
that	O
the	O
shell	B-Device
searches	O
for	O
commands	O
that	O
do	O
not	O
contain	O
a	O
slash	O
in	O
their	O
name	O
(	O
commands	O
with	O
slashes	O
are	O
interpreted	O
as	O
file	O
names	O
to	O
execute	O
,	O
and	O
the	O
shell	B-Device
attempts	O
to	O
execute	O
the	O
files	O
directly	O
)	O
.	O
</s>
<s>
It	O
is	O
equivalent	O
to	O
the	O
DOS	B-Device
,	O
OS/2	B-Application
and	O
Windows	B-Application
%PATH%	B-Application
variable	O
.	O
</s>
<s>
$HOME	O
Contains	O
the	O
location	O
of	O
the	O
user	O
's	O
home	B-Application
directory	I-Application
.	O
</s>
<s>
Although	O
the	O
current	O
user	O
's	O
home	B-Application
directory	I-Application
can	O
also	O
be	O
found	O
out	O
through	O
the	O
C-functions	O
getpwuid	O
and	O
getuid	O
,	O
$HOME	O
is	O
often	O
used	O
for	O
convenience	O
in	O
various	O
shell	B-Language
scripts	I-Language
(	O
and	O
other	O
contexts	O
)	O
.	O
</s>
<s>
$DISPLAY	O
Contains	O
the	O
identifier	O
for	O
the	O
display	O
that	O
X11	B-Operating_System
programs	O
should	O
use	O
by	O
default	O
.	O
</s>
<s>
$LD_LIBRARY_PATH	O
On	O
many	O
Unix	B-Application
systems	I-Application
with	O
a	O
dynamic	B-Application
linker	I-Application
,	O
contains	O
a	O
colon-separated	O
list	O
of	O
directories	O
that	O
the	O
dynamic	B-Application
linker	I-Application
should	O
search	O
for	O
shared	O
objects	O
when	O
building	O
a	O
process	O
image	O
after	O
exec	B-Operating_System
,	O
before	O
searching	O
in	O
any	O
other	O
directories	O
.	O
</s>
<s>
$LIBPATH	O
or	O
$SHLIB_PATH	O
Alternatives	O
to	O
$LD_LIBRARY_PATH	O
typically	O
used	O
on	O
older	O
Unix	B-Application
versions	O
.	O
</s>
<s>
$LANG	O
,	O
$LC_ALL	O
,	O
$	O
LC_	O
...	O
$LANG	O
is	O
used	O
to	O
set	B-Device
to	O
the	O
default	O
locale	B-Device
.	O
</s>
<s>
For	O
example	O
,	O
if	O
the	O
locale	B-Device
values	O
are	O
pt_BR	O
,	O
then	O
the	O
language	O
is	O
set	B-Device
to	O
(	O
Brazilian	O
)	O
Portuguese	O
and	O
Brazilian	O
practice	O
is	O
used	O
where	O
relevant	O
.	O
</s>
<s>
$LC_ALL	O
can	O
be	O
used	O
to	O
force	O
the	O
same	O
locale	B-Device
for	O
all	O
aspects	O
.	O
</s>
<s>
$TZ	O
Refers	O
to	O
time	B-Device
zone	I-Device
.	O
</s>
<s>
It	O
can	O
be	O
in	O
several	O
formats	O
,	O
either	O
specifying	O
the	O
time	B-Device
zone	I-Device
itself	O
or	O
referencing	O
a	O
file	O
(	O
in	O
/usr/share/zoneinfo	O
)	O
.	O
</s>
<s>
$BROWSER	O
Contains	O
a	O
colon-separated	O
list	O
of	O
a	O
user	O
's	O
web	B-Application
browser	I-Application
preferences	O
,	O
for	O
use	O
by	O
programs	O
that	O
need	O
to	O
allow	O
the	O
user	O
to	O
view	O
content	O
at	O
a	O
URL	O
.	O
</s>
<s>
The	O
browsers	B-Application
in	O
the	O
list	O
are	O
intended	O
to	O
be	O
attempted	O
from	O
first	O
to	O
last	O
,	O
stopping	O
after	O
the	O
first	O
one	O
that	O
succeeds	O
.	O
</s>
<s>
This	O
arrangement	O
allows	O
for	O
fallback	O
behavior	O
in	O
different	O
environments	O
,	O
e.g.	O
,	O
in	O
an	O
X11	B-Operating_System
environment	O
,	O
a	O
graphical	O
browser	B-Application
(	O
such	O
as	O
Firefox	B-Application
)	O
can	O
be	O
used	O
,	O
but	O
in	O
a	O
console	O
environment	O
a	O
terminal-base	O
browser	B-Application
(	O
such	O
a	O
Lynx	B-Application
)	O
can	O
be	O
used	O
.	O
</s>
<s>
A	O
%s	O
token	O
may	O
be	O
present	O
to	O
specify	O
where	O
the	O
URL	O
should	O
be	O
placed	O
;	O
otherwise	O
the	O
browser	B-Application
should	O
be	O
launched	O
with	O
the	O
URL	O
as	O
the	O
first	O
argument	O
.	O
</s>
<s>
Under	O
DOS	B-Device
,	O
the	O
master	O
environment	O
is	O
provided	O
by	O
the	O
primary	O
command	O
processor	O
,	O
which	O
inherits	O
the	O
pre-environment	O
defined	O
in	O
CONFIG.SYS	B-Device
when	O
first	O
loaded	O
.	O
</s>
<s>
Local	O
environment	O
segments	O
inherited	O
to	O
child	O
processes	B-Operating_System
are	O
typically	O
reduced	O
down	O
to	O
the	O
size	O
of	O
the	O
contents	O
they	O
hold	O
.	O
</s>
<s>
Some	O
command-line	B-Application
processors	O
(	O
like	O
4DOS	B-Application
)	O
allow	O
to	O
define	O
a	O
minimum	O
amount	O
of	O
free	O
environment	O
space	O
that	O
will	O
be	O
available	O
when	O
launching	O
secondary	O
shells	O
.	O
</s>
<s>
While	O
the	O
content	O
of	O
environment	O
variables	O
remains	O
unchanged	O
upon	O
storage	O
,	O
their	O
names	O
(	O
without	O
the	O
"	O
%	O
"	O
)	O
are	O
always	O
converted	O
to	O
uppercase	O
,	O
with	O
the	O
exception	O
of	O
pre-environment	O
variables	O
defined	O
via	O
the	O
CONFIG.SYS	B-Device
directive	O
SET	B-Device
under	O
DR	B-Application
DOS	I-Application
6.0	O
and	O
higher	O
(	O
and	O
only	O
with	O
SWITCHES	B-Device
=	I-Device
/L	I-Device
(	O
for	O
"	O
allow	O
lowercase	O
names	O
"	O
)	O
under	O
DR-DOS	B-Application
7.02	O
and	O
higher	O
)	O
.	O
</s>
<s>
In	O
principle	O
,	O
MS-DOS	B-Application
7.0	I-Application
and	O
higher	O
also	O
supports	O
lowercase	O
variable	O
names	O
( %windir%	O
)	O
,	O
but	O
provides	O
no	O
means	O
for	O
the	O
user	O
to	O
define	O
them	O
.	O
</s>
<s>
Environment	O
variable	O
names	O
containing	O
lowercase	O
letters	O
are	O
stored	O
in	O
the	O
environment	O
just	O
like	O
normal	O
environment	O
variables	O
,	O
but	O
remain	O
invisible	O
to	O
most	O
DOS	B-Device
software	O
,	O
since	O
they	O
are	O
written	O
to	O
expect	O
uppercase	O
variables	O
only	O
.	O
</s>
<s>
While	O
principally	O
only	O
limited	O
by	O
the	O
size	O
of	O
the	O
environment	O
segment	O
,	O
some	O
DOS	B-Device
and	O
16-bit	O
Windows	B-Application
programs	O
do	O
not	O
expect	O
the	O
contents	O
of	O
environment	O
variables	O
to	O
exceed	O
128	O
characters	O
.	O
</s>
<s>
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
supports	O
environment	O
variables	O
up	O
to	O
255	O
,	O
4DOS	B-Application
even	O
up	O
to	O
512	O
characters	O
.	O
</s>
<s>
Since	O
COMMAND.COM	B-Operating_System
can	O
be	O
configured	O
(	O
via	O
128	O
..	O
1024	O
)	O
to	O
support	O
command	B-Application
lines	I-Application
up	O
to	O
1024	O
characters	O
internally	O
under	O
MS-DOS	B-Application
7.0	I-Application
and	O
higher	O
,	O
environment	O
variables	O
should	O
be	O
expected	O
to	O
contain	O
at	O
least	O
1024	O
characters	O
as	O
well	O
.	O
</s>
<s>
In	O
some	O
versions	O
of	O
DR-DOS	B-Application
,	O
the	O
environment	O
passed	O
to	O
drivers	O
,	O
which	O
often	O
do	O
not	O
need	O
their	O
environment	O
after	O
installation	O
,	O
can	O
be	O
shrunken	O
or	O
relocated	B-Library
through	O
SETENV	O
or	O
INSTALL[HIGH]/LOADHIGH	O
options	O
/Z	O
(	O
zero	O
environment	O
)	O
,	O
/D[:loaddrive]	O
(	O
substitute	O
drive	O
,	O
e.g.	O
</s>
<s>
In	O
batch	B-General_Concept
mode	I-General_Concept
,	O
non-existent	O
environment	O
variables	O
are	O
replaced	O
by	O
a	O
zero-length	O
string	O
.	O
</s>
<s>
%APPEND%	O
(	O
supported	O
since	O
DOS	B-Device
3.3	O
)	O
This	O
variable	O
contains	O
a	O
semicolon-delimited	O
list	O
of	O
directories	O
in	O
which	O
to	O
search	O
for	O
files	O
.	O
</s>
<s>
Some	O
DOS	B-Device
software	O
actually	O
expects	O
the	O
names	O
to	O
be	O
stored	O
in	O
uppercase	O
and	O
the	O
length	O
of	O
the	O
list	O
not	O
to	O
exceed	O
121	O
characters	O
,	O
therefore	O
the	O
variable	O
is	O
best	O
not	O
modified	O
via	O
the	O
SET	B-Device
command	O
.	O
</s>
<s>
%CONFIG%	O
(	O
supported	O
since	O
MS-DOS	O
6.0	O
and	O
PC	O
DOS	B-Device
6.1	O
,	O
also	O
supported	O
by	O
ROM-DOS	O
)	O
This	O
variable	O
holds	O
the	O
symbolic	O
name	O
of	O
the	O
currently	O
chosen	O
boot	O
configuration	O
.	O
</s>
<s>
It	O
is	O
set	B-Device
by	O
the	O
DOS	B-Device
BIOS	B-Operating_System
(	O
IO.SYS	O
,	O
IBMBIO.COM	O
,	O
etc	O
.	O
)	O
</s>
<s>
to	O
the	O
name	O
defined	O
by	O
the	O
corresponding	O
CONFIG.SYS	B-Device
directive	O
MENUITEM	B-Device
before	O
launching	O
the	O
primary	O
command	O
processor	O
.	O
</s>
<s>
Its	O
main	O
purpose	O
is	O
to	O
allow	O
further	O
special	O
cases	O
in	O
AUTOEXEC.BAT	O
and	O
similar	O
batchjobs	B-General_Concept
depending	O
on	O
the	O
selected	O
option	O
at	O
boot	O
time	O
.	O
</s>
<s>
This	O
can	O
be	O
emulated	O
under	O
DR-DOS	B-Application
by	O
utilizing	O
the	O
CONFIG.SYS	B-Device
directive	O
SET	B-Device
like	O
SET	B-Device
CONFIG	O
=	O
1	O
.	O
</s>
<s>
%CMDLINE%	O
(	O
introduced	O
with	O
4DOS	B-Application
,	O
also	O
supported	O
since	O
MS-DOS	B-Application
7.0	I-Application
)	O
This	O
variable	O
contains	O
the	O
fully	O
expanded	O
text	O
of	O
the	O
currently	O
executing	O
command	B-Application
line	I-Application
.	O
</s>
<s>
It	O
can	O
be	O
read	O
by	O
applications	O
to	O
detect	O
the	O
usage	O
of	O
and	O
retrieve	O
long	O
command	B-Application
lines	I-Application
,	O
since	O
the	O
traditional	O
method	O
to	O
retrieve	O
the	O
command	B-Application
line	I-Application
arguments	O
through	O
the	O
PSP	O
(	O
or	O
related	O
API	B-Application
functions	I-Application
)	O
is	O
limited	O
to	O
126	O
characters	O
and	O
is	O
no	O
longer	O
available	O
when	O
FCBs	O
get	O
expanded	O
or	O
the	O
default	O
DTA	O
is	O
used	O
.	O
</s>
<s>
While	O
4DOS	B-Application
supports	O
longer	O
command	B-Application
lines	I-Application
,	O
COMMAND.COM	B-Operating_System
still	O
only	O
supports	O
a	O
maximum	O
of	O
126	O
characters	O
at	O
the	O
prompt	O
by	O
default	O
(	O
unless	O
overridden	O
with	O
128	O
..	O
255	O
to	O
specify	O
the	O
size	O
of	O
the	O
command	B-Application
line	I-Application
buffer	O
)	O
,	O
but	O
nevertheless	O
internal	O
command	B-Application
lines	I-Application
can	O
become	O
longer	O
through	O
f.e.	O
</s>
<s>
In	O
addition	O
to	O
the	O
command-line	B-Application
length	O
byte	O
in	O
the	O
PSP	O
,	O
the	O
PSP	O
command	B-Application
line	I-Application
is	O
normally	O
limited	O
by	O
ASCII-13	O
,	O
and	O
command	B-Application
lines	I-Application
longer	O
than	O
126	O
characters	O
will	O
typically	O
be	O
truncated	O
by	O
having	O
an	O
ASCII-13	O
inserted	O
at	O
position	O
127	O
,	O
but	O
this	O
cannot	O
be	O
relied	O
upon	O
in	O
all	O
scenarios	O
.	O
</s>
<s>
Some	O
beta	O
versions	O
of	O
Windows	B-Application
Chicago	O
used	O
%CMDLINE%	O
to	O
store	O
only	O
the	O
remainder	O
of	O
the	O
command	B-Application
line	I-Application
excessing	O
126	O
characters	O
instead	O
of	O
the	O
complete	O
command	B-Application
line	I-Application
.	O
</s>
<s>
%COMSPEC%	O
(	O
supported	O
since	O
DOS	B-Device
2.0	O
)	O
This	O
variable	O
contains	O
the	O
full	O
8.3	O
path	B-Application
to	O
the	O
command	O
processor	O
,	O
typically	O
C:\COMMAND.COM	O
or	O
C:\DOS\COMMAND.COM	O
.	O
</s>
<s>
It	O
must	O
not	O
contain	O
long	O
filenames	O
,	O
but	O
under	O
DR-DOS	B-Application
it	O
may	O
contain	O
file	O
and	O
directory	O
passwords	O
.	O
</s>
<s>
It	O
is	O
set	B-Device
up	O
by	O
the	O
primary	O
command	O
processor	O
to	O
point	O
to	O
itself	O
(	O
typically	O
reflecting	O
the	O
settings	O
of	O
the	O
CONFIG.SYS	B-Device
directive	O
SHELL	B-Device
)	O
,	O
so	O
that	O
the	O
resident	O
portion	O
of	O
the	O
command	O
processor	O
can	O
reload	O
its	O
transient	O
portion	O
from	O
disk	O
after	O
the	O
execution	O
of	O
larger	O
programs	O
.	O
</s>
<s>
%COPYCMD%	O
(	O
supported	O
since	O
MS-DOS	O
6.2	O
and	O
PC	O
DOS	B-Device
6.3	O
,	O
also	O
supported	O
by	O
ROM-DOS	O
)	O
Allows	O
a	O
user	O
to	O
specify	O
the	O
/Y	O
switch	O
(	O
to	O
assume	O
"	O
Yes	O
"	O
on	O
queries	O
)	O
as	O
the	O
default	O
for	O
the	O
COPY	B-Device
,	O
XCOPY	O
,	O
and	O
MOVE	B-Device
commands	O
.	O
</s>
<s>
A	O
default	O
of	O
/Y	O
can	O
be	O
overridden	O
by	O
supplying	O
the	O
/	O
-Y	O
switch	O
on	O
the	O
command	B-Application
line	I-Application
.	O
</s>
<s>
%DIRCMD%	O
(	O
supported	O
since	O
MS-DOS	O
5.0	O
and	O
PC	O
DOS	B-Device
5.0	O
,	O
also	O
supported	O
by	O
ROM-DOS	O
)	O
Allows	O
a	O
user	O
to	O
specify	O
customized	O
default	O
parameters	O
for	O
the	O
DIR	B-Device
command	O
,	O
including	O
file	O
specifications	O
.	O
</s>
<s>
Preset	O
default	O
switches	B-Device
can	O
be	O
overridden	O
by	O
providing	O
the	O
negative	O
switch	O
on	O
the	O
command	B-Application
line	I-Application
.	O
</s>
<s>
For	O
example	O
,	O
if	O
%DIRCMD%	O
contains	O
the	O
/W	O
switch	O
,	O
then	O
it	O
can	O
be	O
overridden	O
by	O
using	O
DIR	B-Device
/	O
-W	O
at	O
the	O
command	B-Application
line	I-Application
.	O
</s>
<s>
This	O
is	O
similar	O
to	O
the	O
environment	O
variable	O
%$DIR%	O
under	O
DOS	B-Operating_System
Plus	I-Operating_System
and	O
a	O
facility	O
to	O
define	O
default	O
switches	B-Device
for	O
DIR	B-Device
through	O
its	O
/C	O
or	O
/R	O
switches	B-Device
under	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
.	O
</s>
<s>
%DIRCMD%	O
is	O
also	O
supported	O
by	O
the	O
external	O
SDIR.COM/DIR.COM	O
Stacker	O
commands	O
under	O
Novell	O
DOS	B-Device
7	O
and	O
higher	O
.	O
</s>
<s>
%LANG%	O
(	O
supported	O
since	O
MS-DOS	B-Application
7.0	I-Application
)	O
This	O
variable	O
is	O
supported	O
by	O
some	O
tools	O
to	O
switch	O
the	O
locale	B-Device
for	O
messages	O
in	O
multilingual	O
issues	O
.	O
</s>
<s>
%LANGSPEC%	O
(	O
supported	O
since	O
MS-DOS	B-Application
7.0	I-Application
)	O
This	O
variable	O
is	O
supported	O
by	O
some	O
tools	O
to	O
switch	O
the	O
locale	B-Device
for	O
messages	O
in	O
multilingual	O
issues	O
.	O
</s>
<s>
%NO_SEP%	O
(	O
supported	O
since	O
PC	O
DOS	B-Device
6.3	O
and	O
DR-DOS	B-Application
7.07	O
)	O
This	O
variable	O
controls	O
the	O
display	O
of	O
thousands-separators	O
in	O
messages	O
of	O
various	O
commands	O
.	O
</s>
<s>
Issued	O
by	O
default	O
,	O
they	O
can	O
be	O
suppressed	O
by	O
specifying	O
SET	B-Device
NO_SEP	O
=	O
ON	O
or	O
SET	B-Device
NO_SEP	O
=	O
1	O
under	O
PCDOS	O
.	O
</s>
<s>
DR-DOS	B-Application
additionally	O
allows	O
to	O
override	O
the	O
system	O
's	O
thousands-separator	O
displayed	O
as	O
in	O
f.e.	O
</s>
<s>
SET	B-Device
NO_SEP	O
=	O
..	O
</s>
<s>
%PATH%	B-Application
(	O
supported	O
since	O
DOS	B-Device
2.0	O
)	O
This	O
variable	O
contains	O
a	O
semicolon-delimited	O
list	O
of	O
directories	O
in	O
which	O
the	O
command	O
interpreter	O
will	O
search	O
for	O
executable	B-Application
files	I-Application
.	O
</s>
<s>
Equivalent	O
to	O
the	O
Unix	B-Application
$PATH	B-Application
variable	O
(	O
but	O
some	O
DOS	B-Device
and	O
Windows	B-Application
applications	I-Application
also	O
use	O
the	O
list	O
to	O
search	O
for	O
data	O
files	O
similar	O
to	O
$LD_LIBRARY_PATH	O
on	O
Unix-like	B-Operating_System
systems	I-Operating_System
)	O
.	O
</s>
<s>
It	O
is	O
usually	O
changed	O
via	O
the	O
PATH	B-Application
(	O
or	O
PATH	B-Application
/E	O
under	O
MS-DOS	O
6.0	O
)	O
command	O
,	O
which	O
also	O
ensures	O
that	O
the	O
directory	O
names	O
are	O
converted	O
into	O
uppercase	O
.	O
</s>
<s>
Some	O
DOS	B-Device
software	O
actually	O
expects	O
the	O
names	O
to	O
be	O
stored	O
in	O
uppercase	O
and	O
the	O
length	O
of	O
the	O
list	O
not	O
to	O
exceed	O
123	O
characters	O
,	O
therefore	O
the	O
variable	O
should	O
better	O
not	O
be	O
modified	O
via	O
the	O
SET	B-Device
command	O
.	O
</s>
<s>
By	O
default	O
,	O
the	O
current	O
directory	O
is	O
searched	O
first	O
,	O
but	O
some	O
command-line	B-Application
processors	O
like	O
4DOS	B-Application
allow	O
"	O
.	O
"	O
</s>
<s>
(	O
for	O
"	O
current	O
directory	O
"	O
)	O
to	O
be	O
included	O
in	O
the	O
list	O
as	O
well	O
in	O
order	O
to	O
override	O
this	O
search	O
order	O
;	O
some	O
DOS	B-Device
programs	O
are	O
incompatible	O
with	O
this	O
extension	O
.	O
</s>
<s>
%PROMPT%	O
(	O
supported	O
since	O
DOS	B-Device
2.0	O
)	O
This	O
variable	O
contains	O
a	O
$	O
-tokenized	O
string	O
defining	O
the	O
display	O
of	O
the	O
prompt	O
.	O
</s>
<s>
%TEMP%	O
(	O
and	O
%TMP%	O
)	O
These	O
variables	O
contain	O
the	O
path	B-Application
to	O
the	O
directory	O
where	O
temporary	B-Application
files	I-Application
should	O
be	O
stored	O
.	O
</s>
<s>
Operating	B-General_Concept
system	I-General_Concept
tools	O
typically	O
only	O
use	O
%TEMP%	O
,	O
whereas	O
third-party	O
programs	O
also	O
use	O
%TMP%	O
.	O
</s>
<s>
The	O
DR-DOS	B-Application
family	O
supports	O
a	O
number	O
of	O
additional	O
standard	O
environment	O
variables	O
including	O
:	O
</s>
<s>
%BETA%	O
This	O
variable	O
contains	O
an	O
optional	O
message	O
displayed	O
by	O
some	O
versions	O
(	O
including	O
DR	B-Application
DOS	I-Application
3.41	O
)	O
of	O
COMMAND.COM	B-Operating_System
at	O
the	O
startup	O
of	O
secondary	O
shells	O
.	O
</s>
<s>
%DRDOSCFG%	O
/	O
%NWDOSCFG%	O
/	O
%OPENDOSCFG%	O
This	O
variable	O
contains	O
the	O
directory	O
(	O
without	O
trailing	O
"	O
\	O
 "	O
)	O
where	O
to	O
search	O
for	O
.INI	O
and	O
.CFG	O
configuration	O
files	O
(	O
that	O
is	O
,	O
DR-DOS	B-Application
application	O
specific	O
files	O
like	O
TASKMGR.INI	O
,	O
TASKMAX.INI	O
,	O
VIEWMAX.INI	B-Application
,	O
FASTBACK.CFG	O
etc.	O
,	O
class	O
specific	O
files	O
like	O
COLORS.INI	O
,	O
or	O
global	O
files	O
like	O
DRDOS.INI	O
,	O
NWDOS.INI	O
,	O
OPENDOS.INI	O
,	O
or	O
DOS.INI	O
)	O
,	O
as	O
used	O
by	O
the	O
INSTALL	B-Device
and	O
SETUP	O
commands	O
and	O
various	O
DR-DOS	B-Application
programs	O
like	O
DISKOPT	O
,	O
DOSBOOK	O
,	O
EDIT	O
,	O
FBX	B-Application
,	O
FILELINK	O
,	O
LOCK	O
,	O
SECURITY.OVL/NWLOGIN.EXE	O
,	O
SERNO	O
,	O
TASKMAX	O
,	O
TASKMGR	O
,	O
VIEWMAX	B-Application
,	O
or	O
UNDELETE	O
.	O
</s>
<s>
%DRCOMSPEC%	O
This	O
variable	O
optionally	O
holds	O
an	O
alternative	O
path	B-Application
to	O
the	O
command	O
processor	O
taking	O
precedence	O
over	O
the	O
path	B-Application
defined	O
in	O
the	O
%COMSPEC%	O
variable	O
,	O
optionally	O
including	O
file	O
and	O
directory	O
passwords	O
.	O
</s>
<s>
Alternatively	O
,	O
it	O
can	O
hold	O
a	O
special	O
value	O
of	O
"	O
ON	O
"	O
or	O
"	O
1	O
"	O
in	O
order	O
to	O
enforce	O
the	O
usage	O
of	O
the	O
%COMSPEC%	O
variable	O
even	O
in	O
scenarios	O
where	O
the	O
%COMSPEC%	O
variable	O
may	O
point	O
to	O
the	O
wrong	O
command-line	B-Application
processor	O
,	O
for	O
example	O
,	O
when	O
running	O
some	O
versions	O
of	O
the	O
DR-DOS	B-Application
SYS	B-Language
command	I-Language
under	O
a	O
foreign	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
%DRSYS%	O
Setting	O
this	O
variable	O
to	O
"	O
ON	O
"	O
or	O
"	O
1	O
"	O
will	O
force	O
some	O
versions	O
of	O
the	O
DR-DOS	B-Application
SYS	B-Language
command	I-Language
to	O
work	O
under	O
foreign	O
operating	B-General_Concept
systems	I-General_Concept
instead	O
of	O
displaying	O
a	O
warning	O
.	O
</s>
<s>
%FBP_USER%	O
Specifies	O
the	O
user	O
name	O
used	O
by	O
the	O
FastBack	B-Application
command	O
FBX	B-Application
and	O
{user}.FB	O
configuration	O
files	O
under	O
Novell	O
DOS	B-Device
7	O
.	O
</s>
<s>
%HOMEDIR%	O
This	O
variable	O
may	O
contain	O
the	O
home	B-Application
directory	I-Application
under	O
DR-DOS	B-Application
(	O
including	O
DR	B-Application
DOS	I-Application
5.0	O
and	O
6.0	O
)	O
.	O
</s>
<s>
%INFO%	O
In	O
some	O
versions	O
of	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
this	O
variable	O
defines	O
the	O
string	O
displayed	O
by	O
the	O
$I	O
token	O
of	O
the	O
PROMPT	O
command	O
.	O
</s>
<s>
%LOGINNAME%	O
In	O
some	O
versions	O
of	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
this	O
variable	O
defines	O
the	O
user	O
name	O
displayed	O
by	O
the	O
$U	O
token	O
of	O
the	O
PROMPT	O
command	O
,	O
as	O
set	B-Device
up	O
by	O
f.e.	O
</s>
<s>
login	O
scripts	O
for	O
Novell	B-Operating_System
NetWare	I-Operating_System
.	O
</s>
<s>
%MDOS_EXEC%	O
This	O
variable	O
can	O
take	O
the	O
values	O
"	O
ON	O
"	O
or	O
"	O
OFF	O
"	O
under	O
Multiuser	B-Operating_System
DOS	I-Operating_System
.	O
</s>
<s>
If	O
enabled	O
,	O
the	O
operating	B-General_Concept
system	I-General_Concept
permits	O
applications	O
to	O
shell	B-Device
out	O
to	O
secondary	O
shells	O
with	O
the	O
DOS	B-Device
Program	O
Area	O
(	O
DPA	O
)	O
freed	O
in	O
order	O
to	O
have	O
maximum	O
DOS	B-Device
memory	O
available	O
for	O
secondary	O
applications	O
instead	O
of	O
running	O
them	O
in	O
the	O
same	O
domain	O
as	O
under	O
DOS	B-Device
.	O
</s>
<s>
%NOCHAR%	O
This	O
variable	O
can	O
be	O
used	O
to	O
define	O
the	O
character	O
displayed	O
by	O
some	O
commands	O
in	O
messages	O
for	O
"	O
No	O
"	O
in	O
 [ Y , N ] 	O
queries	O
,	O
thereby	O
overriding	O
the	O
current	O
system	O
default	O
(	O
typically	O
"	O
N	O
"	O
in	O
English	O
versions	O
of	O
DR-DOS	B-Application
)	O
.	O
</s>
<s>
Some	O
commands	O
also	O
support	O
a	O
command	B-Application
line	I-Application
parameter	O
/Y	O
to	O
automatically	O
assume	O
"	O
Yes	O
"	O
on	O
queries	O
,	O
thereby	O
suppressing	O
such	O
prompts	O
.	O
</s>
<s>
If	O
,	O
however	O
,	O
the	O
parameter	O
/Y:yn	O
is	O
used	O
to	O
specify	O
the	O
"	O
Yes	O
"	O
/	O
"	O
No	O
"	O
characters	O
(	O
thereby	O
overriding	O
any	O
%NOCHAR%	O
setting	O
)	O
,	O
queries	O
are	O
not	O
suppressed	O
.	O
</s>
<s>
See	O
also	O
the	O
related	O
CONFIG.SYS	B-Device
directive	O
NOCHAR	B-Device
and	O
the	O
environment	O
variable	O
%YESCHAR%	O
.	O
</s>
<s>
%NOSOUND%	O
Setting	O
this	O
variable	O
to	O
"	O
ON	O
"	O
or	O
"	O
1	O
"	O
will	O
disable	O
default	O
beeps	O
issued	O
by	O
some	O
DR-DOS	B-Application
commands	O
in	O
certain	O
situations	O
such	O
as	O
to	O
inform	O
the	O
user	O
of	O
the	O
completion	O
of	O
some	O
operation	O
,	O
that	O
user	O
interaction	O
is	O
required	O
,	O
or	O
when	O
a	O
wrong	O
key	O
was	O
pressed	O
.	O
</s>
<s>
Command	B-Application
line	I-Application
options	I-Application
to	O
specifically	O
enable	O
certain	O
beeps	O
will	O
override	O
this	O
setting	O
.	O
</s>
<s>
%OS%This	O
variable	O
contains	O
the	O
name	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
in	O
order	O
to	O
distinguish	O
between	O
different	O
DOS-related	O
operating	B-General_Concept
systems	I-General_Concept
of	O
Digital	O
Research-origin	O
in	O
batch	B-General_Concept
jobs	I-General_Concept
and	O
applications	O
.	O
</s>
<s>
Known	O
values	O
include	O
"	O
DOSPLUS	B-Operating_System
"	O
(	O
DOS	B-Operating_System
Plus	I-Operating_System
1.2	O
in	O
DOS	B-Device
emulation	O
)	O
,	O
"	O
CPCDOS	O
4.1	O
"	O
(	O
DOS	B-Operating_System
Plus	I-Operating_System
1.2	O
in	O
CP/M	B-Application
emulation	O
)	O
,	O
"	O
DRDOS	B-Application
"	O
(	O
DR	B-Application
DOS	I-Application
3.31-6.0	O
,	O
DR	B-Application
DOS	I-Application
Panther	O
,	O
DR	B-Application
DOS	I-Application
StarTrek	O
,	O
DR-DOS	B-Application
7.02-7.05	O
)	O
,	O
"	O
EZDOS	O
"	O
(	O
EZ-DOS	O
3.41	O
)	O
,	O
"	O
PALMDOS	O
"	O
and	O
"	O
NetWare	B-Operating_System
PalmDOS	O
"	O
(	O
PalmDOS	O
1.0	O
)	O
,	O
"	O
NWDOS	O
"	O
(	O
Novell	O
DOS	B-Device
7	O
)	O
,	O
"	O
NWDOS7	O
"	O
(	O
Novell	O
DOS	B-Device
7	O
Beta	O
)	O
,	O
"	O
OPENDOS	O
"	O
(	O
Caldera	O
OpenDOS	O
7.01	O
,	O
Caldera	O
DR-OpenDOS	O
7.02	O
)	O
,	O
"	O
CDOS	O
"	O
(	O
Concurrent	B-Operating_System
DOS	I-Operating_System
,	O
Concurrent	B-Operating_System
DOS	I-Operating_System
XM	I-Operating_System
)	O
,	O
"	O
CPCDOS	O
"	O
(	O
Concurrent	B-Operating_System
PC	I-Operating_System
DOS	I-Operating_System
)	O
,	O
"	O
CDOS386	O
"	O
(	O
Concurrent	B-Operating_System
DOS	I-Operating_System
386	I-Operating_System
)	O
,	O
"	O
DRMDOS	O
"	O
(	O
DR	B-Operating_System
Multiuser	I-Operating_System
DOS	I-Operating_System
)	O
,	O
"	O
MDOS	O
"	O
(	O
CCI	B-Operating_System
Multiuser	I-Operating_System
DOS	I-Operating_System
)	O
,	O
"	O
IMSMDOS	O
"	O
(	O
IMS	O
Multiuser	B-Operating_System
DOS	I-Operating_System
)	O
,	O
"	O
REAL32	O
"	O
(	O
REAL/32	B-Operating_System
)	O
.	O
</s>
<s>
MS-DOS	O
INTERSVR	O
looks	O
for	O
a	O
value	O
of	O
"	O
DRDOS	B-Application
"	O
as	O
well	O
.	O
</s>
<s>
See	O
also	O
the	O
identically	O
named	O
environment	O
variable	O
%OS%	O
later	O
introduced	O
in	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
.	O
</s>
<s>
%PEXEC%	O
In	O
some	O
versions	O
of	O
DR-DOS	B-Application
this	O
variable	O
defines	O
the	O
command	O
executed	O
by	O
the	O
$X	O
token	O
of	O
the	O
PROMPT	O
command	O
before	O
COMMAND.COM	B-Operating_System
displays	O
the	O
prompt	O
after	O
returning	O
from	O
external	O
program	O
execution	O
.	O
</s>
<s>
%SWITCHAR%	O
This	O
variable	O
defines	O
the	O
SwitChar	B-Device
to	O
be	O
used	O
for	O
argument	O
parsing	O
by	O
some	O
DR-DOS	B-Application
commands	O
.	O
</s>
<s>
If	O
defined	O
,	O
it	O
overrides	O
the	O
system	O
's	O
current	O
SwitChar	B-Device
setting	O
.	O
</s>
<s>
The	O
only	O
accepted	O
characters	O
are	O
"	O
/	O
"	O
(	O
DOS	B-Device
style	O
)	O
,	O
"	O
-	O
"	O
(	O
Unix	B-Application
style	O
)	O
and	O
"	O
[	O
"	O
(	O
CP/M	B-Application
style	O
)	O
.	O
</s>
<s>
See	O
also	O
the	O
related	O
CONFIG.SYS	B-Device
directive	O
SWITCHAR	B-Device
(	O
to	O
set	B-Device
the	O
system	O
's	O
SwitChar	B-Device
setting	O
)	O
and	O
the	O
%	O
/	O
%	O
system	O
information	O
variable	O
in	O
some	O
issues	O
of	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
(	O
to	O
retrieve	O
the	O
current	O
setting	O
for	O
portable	O
batchjobs	B-General_Concept
)	O
.	O
</s>
<s>
%TASKMGRWINDIR%	O
This	O
variable	O
specifies	O
the	O
directory	O
,	O
where	O
the	O
Windows	B-Application
SYSTEM.INI	B-Protocol
to	O
be	O
used	O
by	O
the	O
DR-DOS	B-Application
TASKMGR	O
multitasker	O
is	O
located	O
,	O
overriding	O
the	O
default	O
procedure	O
to	O
locate	O
the	O
file	O
.	O
</s>
<s>
%VER%	O
This	O
variable	O
contains	O
the	O
version	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
in	O
order	O
to	O
distinguish	O
between	O
different	O
versions	O
of	O
DR-DOS	B-Application
in	O
batch	B-General_Concept
jobs	I-General_Concept
and	O
in	O
the	O
display	O
of	O
the	O
VER	B-Device
command	O
.	O
</s>
<s>
Known	O
values	O
include	O
"	O
1.0	O
"	O
(	O
PalmDOS	O
1.0	O
)	O
,	O
"	O
1.2	O
"	O
(	O
DOS	B-Operating_System
Plus	I-Operating_System
1.2	O
in	O
DOS	B-Device
emulation	O
)	O
,	O
"	O
2.0	O
"	O
(	O
Concurrent	B-Operating_System
DOS	I-Operating_System
386	I-Operating_System
2.0	O
)	O
,	O
"	O
3.0	O
"	O
(	O
Concurrent	B-Operating_System
DOS	I-Operating_System
386	I-Operating_System
3.0	O
)	O
,	O
"	O
3.31	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.31	O
)	O
,	O
"	O
3.32	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.32	O
)	O
,	O
"	O
3.33	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.33	O
)	O
,	O
"	O
3.34	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.34	O
)	O
,	O
"	O
3.35	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.35	O
)	O
,	O
"	O
3.40	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.40	O
)	O
,	O
"	O
3.41	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.41	O
,	O
EZ-DOS	O
3.41	O
)	O
,	O
"	O
3.41T	O
"	O
(	O
DR	B-Application
DOS	I-Application
3.41T	O
)	O
,	O
"	O
4.1	O
"	O
(	O
Concurrent	B-Operating_System
PC	I-Operating_System
DOS	I-Operating_System
4.1	O
)	O
,	O
"	O
5.0	O
"	O
(	O
DR	B-Application
DOS	I-Application
5.0	O
,	O
DR	B-Operating_System
Multiuser	I-Operating_System
DOS	I-Operating_System
5.0	O
)	O
,	O
"	O
5.1	O
"	O
(	O
Novell	B-Operating_System
DR	I-Operating_System
Multiuser	I-Operating_System
DOS	I-Operating_System
5.1	O
)	O
,	O
"	O
6.0	O
"	O
(	O
DR	O
Concurrent	B-Operating_System
DOS	I-Operating_System
XM	I-Operating_System
6.0	O
,	O
DR	B-Application
DOS	I-Application
6.0	O
)	O
,	O
"	O
6.2	O
"	O
(	O
DR	O
Concurrent	B-Operating_System
DOS	I-Operating_System
XM	I-Operating_System
6.2	O
)	O
,	O
"	O
7	O
"	O
(	O
Novell	O
DOS	B-Device
7	O
,	O
Caldera	O
OpenDOS	O
7.01	O
,	O
DR-DOS	B-Application
7.02-7.05	O
)	O
,	O
"	O
7.00	O
"	O
(	O
CCI	B-Operating_System
Multiuser	I-Operating_System
DOS	I-Operating_System
7.00	O
)	O
,	O
"	O
7.07	O
"	O
(	O
DR-DOS	B-Application
7.07	O
)	O
,	O
"	O
7.1	O
"	O
(	O
IMS	O
Multiuser	B-Operating_System
DOS	I-Operating_System
7.1	O
)	O
,	O
"	O
7.21	O
"	O
(	O
CCI	B-Operating_System
Multiuser	I-Operating_System
DOS	I-Operating_System
7.21	O
)	O
,	O
"	O
7.22	O
"	O
(	O
CCI	B-Operating_System
Multiuser	I-Operating_System
DOS	I-Operating_System
7.22	O
)	O
etc	O
.	O
</s>
<s>
%YESCHAR%This	O
variable	O
can	O
be	O
used	O
to	O
define	O
the	O
character	O
displayed	O
by	O
some	O
commands	O
in	O
messages	O
for	O
"	O
Yes	O
"	O
in	O
 [ Y , N ] 	O
queries	O
,	O
thereby	O
overriding	O
the	O
current	O
system	O
default	O
(	O
typically	O
"	O
Y	O
"	O
in	O
English	O
versions	O
of	O
DR-DOS	B-Application
)	O
.	O
</s>
<s>
Some	O
commands	O
also	O
support	O
a	O
command	B-Application
line	I-Application
parameter	O
/Y	O
to	O
automatically	O
assume	O
"	O
Yes	O
"	O
on	O
queries	O
,	O
thereby	O
suppressing	O
such	O
prompts	O
.	O
</s>
<s>
If	O
,	O
however	O
,	O
the	O
parameter	O
/Y:y	O
is	O
used	O
to	O
specify	O
the	O
"	O
Yes	O
"	O
character	O
(	O
thereby	O
overriding	O
any	O
%YESCHAR%	O
setting	O
)	O
,	O
queries	O
are	O
not	O
suppressed	O
.	O
</s>
<s>
See	O
also	O
the	O
related	O
CONFIG.SYS	B-Device
directive	O
YESCHAR	B-Device
and	O
the	O
environment	O
variable	O
%NOCHAR%	O
.	O
</s>
<s>
%$CLS%	O
This	O
variable	O
defines	O
the	O
control	O
sequence	O
to	O
be	O
sent	O
to	O
the	O
console	O
driver	O
to	O
clear	O
the	O
screen	O
when	O
the	O
CLS	O
command	O
is	O
issued	O
,	O
thereby	O
overriding	O
the	O
internal	O
default	O
(	O
"	O
←	O
[ 2J	O
"	O
under	O
DR-DOS	B-Application
,	O
"	O
←	O
E	O
"	O
under	O
DOS	B-Operating_System
Plus	I-Operating_System
1.2	O
on	O
Amstrad	O
machines	O
as	O
well	O
as	O
under	O
Concurrent	B-Operating_System
DOS	I-Operating_System
,	O
Multiuser	B-Operating_System
DOS	I-Operating_System
,	O
and	O
REAL/32	B-Operating_System
for	O
VT52	B-Application
terminals	O
,	O
or	O
"	O
←	O
+	O
"	O
under	O
Multiuser	B-Operating_System
DOS	I-Operating_System
for	O
ASCII	B-Protocol
terminals	O
)	O
.	O
</s>
<s>
If	O
the	O
variable	O
is	O
not	O
defined	O
and	O
no	O
ANSI.SYS	O
console	O
driver	O
is	O
detected	O
,	O
the	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
will	O
directly	O
clear	O
the	O
screen	O
via	O
INT	O
10h/AH	O
=	O
00h	O
BIOS	B-Operating_System
function	O
,	O
like	O
MS-DOS/PCDOS	O
COMMAND.COM	B-Operating_System
does	O
.	O
</s>
<s>
A	O
special	O
\nnn-notation	O
for	O
octal	O
numbers	O
is	O
supported	O
to	O
allow	O
the	O
definition	O
of	O
special	O
characters	O
like	O
ESC	O
(	O
ASCII-27	B-Algorithm
=	O
"	O
←	O
"	O
=	O
1Bh	O
=	O
33o	O
)	O
,	O
as	O
f.e.	O
</s>
<s>
in	O
SET	B-Device
$CLS	O
=	O
\033[ 2J	O
.	O
</s>
<s>
%$DIR%	O
Supported	O
by	O
DOS	B-Operating_System
Plus	I-Operating_System
accepting	O
the	O
values	O
"	O
L	O
"	O
(	O
long	O
)	O
or	O
"	O
W	O
"	O
(	O
wide	O
)	O
to	O
change	O
the	O
default	O
layout	O
of	O
directory	O
listings	O
with	O
DIR	B-Device
.	O
</s>
<s>
Can	O
be	O
overridden	O
using	O
the	O
command	B-Application
line	I-Application
options	I-Application
/L	O
or	O
/W	O
.	O
</s>
<s>
See	O
also	O
the	O
similar	O
environment	O
variable	O
%DIRCMD%	O
and	O
the	O
DIR	B-Device
options	O
/C	O
and	O
/R	O
of	O
the	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
.	O
</s>
<s>
%$PAGE%	O
Supported	O
by	O
DOS	B-Operating_System
Plus	I-Operating_System
accepting	O
the	O
values	O
"	O
ON	O
"	O
or	O
"	O
OFF	O
"	O
for	O
pagination	O
control	O
.	O
</s>
<s>
Setting	O
this	O
to	O
"	O
ON	O
"	O
has	O
the	O
same	O
affect	O
as	O
adding	O
/P	O
to	O
commands	O
supporting	O
it	O
(	O
like	O
DIR	B-Device
or	O
TYPE	B-Device
)	O
.	O
</s>
<s>
%$LENGTH%	O
Used	O
by	O
DOS	B-Operating_System
Plus	I-Operating_System
to	O
define	O
the	O
screen	O
length	O
of	O
the	O
console	O
in	O
lines	O
.	O
</s>
<s>
%$WIDTH%	O
Used	O
by	O
DOS	B-Operating_System
Plus	I-Operating_System
to	O
define	O
the	O
screen	O
width	O
of	O
the	O
console	O
in	O
columns	O
.	O
</s>
<s>
This	O
is	O
used	O
to	O
control	O
in	O
a	O
portable	O
way	O
the	O
formatting	O
of	O
the	O
screen	O
output	O
of	O
commands	O
like	O
DIR	B-Device
/W	O
or	O
TYPE	B-Device
filename	O
.	O
</s>
<s>
%$SLICE%	O
Used	O
by	O
DOS	B-Operating_System
Plus	I-Operating_System
accepting	O
a	O
numerical	O
value	O
to	O
control	O
the	O
foreground/background	O
time	O
slicing	O
of	O
multitasking	O
programs	O
.	O
</s>
<s>
See	O
also	O
the	O
DOS	B-Operating_System
Plus	I-Operating_System
command	O
SLICE	O
.	O
</s>
<s>
It	O
is	O
used	O
to	O
emphasize	O
or	O
otherwise	O
control	O
the	O
display	O
of	O
the	O
file	O
names	O
in	O
commands	O
like	O
TYPE	B-Device
wildcard	O
,	O
for	O
example	O
SET	B-Device
$ON	O
=	O
\033[ 1m	O
with	O
ANSI.SYS	O
loaded	O
or	O
SET	B-Device
$ON	O
=	O
\016	O
for	O
an	O
IBM	O
or	O
ESC/P	B-Language
printer	O
.	O
</s>
<s>
While	O
the	O
variable	O
is	O
undefined	O
by	O
default	O
under	O
DOS	B-Operating_System
Plus	I-Operating_System
and	O
DR-DOS	B-Application
,	O
the	O
Multiuser	B-Operating_System
DOS	I-Operating_System
default	O
for	O
an	O
ASCII	B-Protocol
terminal	O
equals	O
SET	B-Device
$ON	O
=	O
\033p	O
.	O
</s>
<s>
It	O
is	O
used	O
to	O
return	O
to	O
the	O
normal	O
output	O
after	O
the	O
display	O
of	O
file	O
names	O
in	O
commands	O
like	O
TYPE	B-Device
wildcard	O
,	O
for	O
example	O
SET	B-Device
$OFF	O
=	O
\033[ 0m	O
with	O
ANSI.SYS	O
loaded	O
or	O
SET	B-Device
$OFF	O
=	O
\024	O
for	O
an	O
IBM	O
or	O
ESC/P	B-Language
printer	O
.	O
</s>
<s>
While	O
the	O
variable	O
is	O
undefined	O
by	O
default	O
under	O
DOS	B-Operating_System
Plus	I-Operating_System
and	O
DR-DOS	B-Application
,	O
the	O
Multiuser	B-Operating_System
DOS	I-Operating_System
default	O
for	O
an	O
ASCII	B-Protocol
terminal	O
equals	O
SET	B-Device
$OFF	O
=	O
\033q	O
.	O
</s>
<s>
%$HEADER%	O
This	O
variable	O
can	O
hold	O
an	O
optional	O
control	O
sequence	O
issued	O
before	O
the	O
output	O
of	O
the	O
file	O
contents	O
in	O
commands	O
like	O
TYPE	B-Device
under	O
DR-DOS	B-Application
7.02	O
and	O
higher	O
.	O
</s>
<s>
SET	B-Device
$HEADER	O
=	O
\017	O
for	O
an	O
IBM	O
or	O
ESC/P	B-Language
printer	O
.	O
</s>
<s>
%$FOOTER%	O
This	O
variable	O
can	O
hold	O
an	O
optional	O
control	O
sequence	O
issued	O
after	O
the	O
output	O
of	O
the	O
file	O
contents	O
in	O
commands	O
like	O
TYPE	B-Device
under	O
DR-DOS	B-Application
7.02	O
and	O
higher	O
.	O
</s>
<s>
SET	B-Device
$FOOTER	O
=	O
\022\014	O
in	O
the	O
printer	O
example	O
above	O
.	O
</s>
<s>
Datalight	O
ROM-DOS	O
supports	O
a	O
number	O
of	O
additional	O
standard	O
environment	O
variables	O
as	O
well	O
including	O
:	O
</s>
<s>
%DIRSIZE%	O
This	O
variable	O
is	O
used	O
to	O
define	O
non-standard	O
screen	O
sizes	O
rows[,cols]	O
for	O
DIR	B-Device
options	O
/P	O
and	O
/W	O
(	O
similar	O
to	O
%$LENGTH%	O
and	O
%$WIDTH%	O
under	O
DOS	B-Operating_System
Plus	I-Operating_System
)	O
.	O
</s>
<s>
%NEWFILE%	O
This	O
variable	O
is	O
automatically	O
set	B-Device
to	O
the	O
first	O
parameter	O
given	O
to	O
the	O
CONFIG.SYS	B-Device
directive	O
NEWFILE	B-Device
.	O
</s>
<s>
%TZ%	O
,	O
%COMM%	O
,	O
%SOCKETS%	O
,	O
%HTTP_DIR%	O
,	O
%HOSTNAME%	O
and	O
%FTPDIR%	O
are	O
also	O
used	O
by	O
ROM-DOS	O
.	O
</s>
<s>
%BEGINLIBPATH%	O
Contains	O
a	O
semicolon-separated	O
list	O
of	O
directories	O
which	O
are	O
searched	O
for	O
DLLs	O
before	O
the	O
directories	O
given	O
by	O
the	O
%LIBPATH%	B-Device
variable	O
(	O
which	O
is	O
set	B-Device
during	O
system	O
startup	O
with	O
the	O
special	O
CONFIG.SYS	B-Device
directive	O
LIBPATH	B-Device
)	O
.	O
</s>
<s>
See	O
also	O
the	O
related	O
environment	O
variable	O
%ENDLIBPATH%	O
.	O
</s>
<s>
%ENDLIBPATH%	O
a	O
list	O
of	O
directories	O
to	O
be	O
searched	O
for	O
DLLs	O
like	O
%BEGINLIBPATH%	O
,	O
but	O
searched	O
after	O
the	O
list	O
of	O
directories	O
in	O
%LIBPATH%	B-Device
.	O
</s>
<s>
System	O
path	B-Application
variables	I-Application
refer	O
to	O
locations	O
of	O
critical	O
operating	B-General_Concept
system	I-General_Concept
resources	O
,	O
and	O
as	O
such	O
generally	O
are	O
not	O
user-dependent	O
.	O
</s>
<s>
%APPDATA%	O
Contains	O
the	O
full	O
path	B-Application
to	O
the	O
Application	B-General_Concept
Data	I-General_Concept
directory	O
of	O
the	O
logged-in	O
user	O
.	O
</s>
<s>
Does	O
not	O
work	O
on	O
Windows	B-Device
NT	I-Device
4.0	I-Device
SP6	O
UK	O
.	O
</s>
<s>
%LOCALAPPDATA%	O
This	O
variable	O
is	O
the	O
temporary	B-Application
files	I-Application
of	O
Applications	O
.	O
</s>
<s>
Its	O
uses	O
include	O
storing	O
of	O
desktop	B-Application
themes	I-Application
,	O
Windows	B-Application
error	O
reporting	O
,	O
caching	O
and	O
profiles	O
of	O
web	B-Application
browsers	I-Application
.	O
</s>
<s>
%ComSpec%	O
/	O
%COMSPEC%The	O
%ComSpec%	O
variable	O
contains	O
the	O
full	O
path	B-Application
to	O
the	O
command	O
processor	O
;	O
on	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
of	O
operating	B-General_Concept
systems	I-General_Concept
,	O
this	O
is	O
cmd.exe	B-Device
,	O
while	O
on	O
Windows	B-Application
9x	O
,	O
%COMSPEC%	O
is	O
COMMAND.COM	B-Operating_System
.	O
</s>
<s>
%OS%The	O
%OS%	O
variable	O
contains	O
a	O
symbolic	O
name	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
family	O
to	O
distinguish	O
between	O
differing	O
feature	O
sets	O
in	O
batchjobs	B-General_Concept
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
environment	O
variable	O
%OS%	O
found	O
in	O
all	O
DOS-related	O
operating	B-General_Concept
systems	I-General_Concept
of	O
Digital	O
Research-origin	O
like	O
Concurrent	B-Operating_System
DOS	I-Operating_System
,	O
Multiuser	B-Operating_System
DOS	I-Operating_System
,	O
REAL/32	B-Operating_System
,	O
DOS	B-Operating_System
Plus	I-Operating_System
,	O
DR	B-Application
DOS	I-Application
,	O
Novell	O
DOS	B-Device
and	O
OpenDOS	O
.	O
</s>
<s>
%OS%	O
always	O
holds	O
the	O
string	O
"	O
Windows_NT	O
"	O
on	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
.	O
</s>
<s>
%PATH%	B-Application
This	O
variable	O
contains	O
a	O
semicolon-delimited	O
(	O
do	O
not	O
put	O
spaces	O
in	O
between	O
)	O
list	O
of	O
directories	O
in	O
which	O
the	O
command	O
interpreter	O
will	O
search	O
for	O
an	O
executable	B-Application
file	I-Application
that	O
matches	O
the	O
given	O
command	O
.	O
</s>
<s>
Environment	O
variables	O
that	O
represent	O
paths	O
may	O
be	O
nested	O
within	O
the	O
%PATH%	B-Application
variable	O
,	O
but	O
only	O
at	O
one	O
level	O
of	O
indirection	O
.	O
</s>
<s>
If	O
this	O
sub-path	O
environment	O
variable	O
itself	O
contains	O
an	O
environment	O
variable	O
representing	O
a	O
path	B-Application
,	O
%PATH%	B-Application
will	O
not	O
expand	O
properly	O
in	O
the	O
variable	O
substitution	O
.	O
</s>
<s>
Equivalent	O
to	O
the	O
Unix	B-Application
$PATH	B-Application
variable	O
.	O
</s>
<s>
%ProgramFiles%	O
,	O
%	O
ProgramFiles(x86 )	O
%	O
,	O
%ProgramW6432%	O
The	O
%ProgramFiles%	O
variable	O
points	O
to	O
the	O
Program	O
Files	O
directory	O
,	O
which	O
stores	O
all	O
the	O
installed	O
programs	O
of	O
Windows	B-Application
and	O
others	O
.	O
</s>
<s>
In	O
64-bit	O
editions	O
of	O
Windows	B-Application
(	O
XP	B-Application
,	O
2003	O
,	O
Vista	O
)	O
,	O
there	O
are	O
also	O
%	O
ProgramFiles(x86 )	O
%	O
,	O
which	O
defaults	O
to	O
"	O
C:\Program	O
Files	O
(	O
x86	O
)	O
"	O
,	O
and	O
%ProgramW6432%	O
,	O
which	O
defaults	O
to	O
"	O
C:\Program	O
Files	O
"	O
.	O
</s>
<s>
The	O
%ProgramFiles%	O
itself	O
depends	O
on	O
whether	O
the	O
process	O
requesting	O
the	O
environment	O
variable	O
is	O
itself	O
32-bit	O
or	O
64-bit	O
(	O
this	O
is	O
caused	O
by	O
Windows-on-Windows	B-Application
64-bit	I-Application
redirection	O
)	O
.	O
</s>
<s>
The	O
default	O
is	O
"	O
C:\Program	O
Files	O
\Common	O
Files	O
"	O
in	O
the	O
English	O
version	O
of	O
Windows	B-Application
.	O
</s>
<s>
%OneDrive%	O
The	O
%OneDrive%	O
variable	O
is	O
a	O
special	O
system-wide	O
environment	O
variable	O
found	O
on	O
Windows	B-Device
NT	I-Device
and	O
its	O
derivatives	O
.	O
</s>
<s>
Its	O
value	O
is	O
the	O
path	B-Application
of	O
where	O
(	O
if	O
installed	O
and	O
setup	O
)	O
the	O
Onedrive	O
directory	O
is	O
located	O
.	O
</s>
<s>
%SystemDrive%	O
The	O
%SystemDrive%	O
variable	O
is	O
a	O
special	O
system-wide	O
environment	O
variable	O
found	O
on	O
Windows	B-Device
NT	I-Device
and	O
its	O
derivatives	O
.	O
</s>
<s>
%SystemRoot%The	O
%SystemRoot%	O
variable	O
is	O
a	O
special	O
system-wide	O
environment	O
variable	O
found	O
on	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
of	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
Its	O
value	O
is	O
the	O
location	O
of	O
the	O
system	O
directory	O
,	O
including	O
the	O
drive	O
and	O
path	B-Application
.	O
</s>
<s>
The	O
drive	O
is	O
the	O
same	O
as	O
%SystemDrive%	O
and	O
the	O
default	O
path	B-Application
on	O
a	O
clean	O
installation	O
depends	O
upon	O
the	O
version	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Windows	B-Application
XP	I-Application
and	O
newer	O
versions	O
use	O
"	O
\WINDOWS	O
 "	O
.	O
</s>
<s>
Windows	B-Application
2000	I-Application
,	O
NT	B-Device
4.0	I-Device
and	O
NT	B-Device
3.1	I-Device
use	O
"	O
\WINNT	O
 "	O
.	O
</s>
<s>
Windows	B-Device
NT	I-Device
3.5	I-Device
and	O
NT	B-Device
3.51	I-Device
uses	O
"	O
\WINNT35	O
 "	O
.	O
</s>
<s>
Windows	B-Device
NT	I-Device
4.0	I-Device
Terminal	O
Server	O
uses	O
"	O
\WTSRV	O
 "	O
.	O
</s>
<s>
%windir%This	O
variable	O
points	O
to	O
the	O
Windows	B-Application
directory	O
.	O
</s>
<s>
(	O
On	O
the	O
Windows	B-Device
NT	I-Device
family	I-Device
of	O
operating	B-General_Concept
systems	I-General_Concept
,	O
it	O
is	O
identical	O
to	O
the	O
%SystemRoot%	O
variable	O
)	O
.	O
</s>
<s>
Windows	B-Application
95	I-Application
–	O
98	B-Device
and	O
Windows	B-Device
ME	I-Device
are	O
,	O
by	O
default	O
,	O
installed	O
in	O
"	O
C:\Windows	O
 "	O
.	O
</s>
<s>
For	O
other	O
versions	O
of	O
Windows	B-Application
,	O
see	O
the	O
%SystemRoot%	O
entry	O
above	O
.	O
</s>
<s>
%ALLUSERSPROFILE%	O
( %PROGRAMDATA%	O
since	O
Windows	B-Application
Vista	O
)	O
This	O
variable	O
expands	O
to	O
the	O
full	O
path	B-Application
to	O
the	O
All	O
Users	O
profile	O
directory	O
.	O
</s>
<s>
Shortcut	O
links	O
copied	O
to	O
the	O
All	O
Users\	O
 '	O
Start	O
menu	O
or	O
Desktop	B-Application
directories	O
will	O
appear	O
in	O
every	O
user	O
's	O
Start	O
menu	O
or	O
Desktop	B-Application
,	O
respectively	O
.	O
</s>
<s>
%USERDOMAIN%	O
The	O
name	O
of	O
the	O
Workgroup	B-Device
or	O
Windows	B-General_Concept
Domain	I-General_Concept
to	O
which	O
the	O
current	O
user	O
belongs	O
.	O
</s>
<s>
The	O
related	O
variable	O
,	O
%LOGONSERVER%	O
,	O
holds	O
the	O
hostname	B-Protocol
of	O
the	O
server	O
that	O
authenticated	O
the	O
current	O
user	O
's	O
login	O
credentials	O
(	O
name	O
and	O
password	O
)	O
.	O
</s>
<s>
For	O
home	O
PCs	O
and	O
PCs	O
in	O
a	O
workgroup	B-Device
,	O
the	O
authenticating	O
server	O
is	O
usually	O
the	O
PC	O
itself	O
.	O
</s>
<s>
For	O
PCs	O
in	O
a	O
Windows	B-General_Concept
domain	I-General_Concept
,	O
the	O
authenticating	O
server	O
is	O
a	O
domain	B-Protocol
controller	I-Protocol
(	O
a	O
primary	O
domain	B-Protocol
controller	I-Protocol
,	O
or	O
PDC	O
,	O
in	O
Windows	O
NT	O
4-based	O
domains	O
)	O
.	O
</s>
<s>
%USERPROFILE%	O
A	O
special	O
system-wide	O
environment	O
variable	O
found	O
on	O
Windows	B-Device
NT	I-Device
and	O
its	O
derivatives	O
.	O
</s>
<s>
These	O
variables	O
also	O
do	O
not	O
need	O
to	O
be	O
explicitly	O
specified	O
as	O
command	B-Application
line	I-Application
arguments	O
.	O
</s>
<s>
The	O
following	O
tables	O
shows	O
typical	O
default	O
values	O
of	O
certain	O
environment	O
variables	O
under	O
English	O
versions	O
of	O
Windows	B-Application
as	O
they	O
can	O
be	O
retrieved	O
under	O
CMD	B-Device
.	O
</s>
<s>
(	O
Some	O
of	O
these	O
variables	O
are	O
also	O
defined	O
when	O
running	O
COMMAND.COM	B-Operating_System
under	O
Windows	B-Application
,	O
but	O
differ	O
in	O
certain	O
important	O
details	O
:	O
Under	O
COMMAND.COM	B-Operating_System
,	O
the	O
names	O
of	O
environment	O
variable	O
are	O
always	O
uppercased	O
.	O
</s>
<s>
While	O
some	O
variables	O
present	O
in	O
the	O
CMD	B-Device
environment	O
are	O
missing	O
,	O
there	O
are	O
also	O
some	O
variables	O
specific	O
to	O
the	O
COMMAND	O
environment	O
.	O
)	O
</s>
<s>
In	O
this	O
list	O
,	O
there	O
is	O
no	O
environment	O
variable	O
that	O
refers	O
to	O
the	O
location	O
of	O
the	O
user	O
's	O
My	O
Documents	O
directory	O
,	O
so	O
there	O
is	O
no	O
standard	O
method	O
for	O
setting	O
a	O
program	O
's	O
home	B-Application
directory	I-Application
to	O
be	O
the	O
My	O
Documents	O
directory	O
.	O
</s>
<s>
The	O
command	O
processors	O
in	O
DOS	B-Device
and	O
Windows	B-Application
also	O
support	O
pseudo-environment	O
variables	O
.	O
</s>
<s>
Besides	O
true	O
environment	O
variables	O
,	O
which	O
are	O
statically	O
stored	O
in	O
the	O
environment	O
until	O
changed	O
or	O
deleted	O
,	O
a	O
number	O
of	O
pseudo-environment	O
variables	O
exist	O
for	O
batch	B-General_Concept
processing	I-General_Concept
.	O
</s>
<s>
The	O
so-called	O
replacement	O
parameters	O
or	O
replaceable	O
parameters	O
(	O
Microsoft	O
/	O
IBM	O
terminology	O
)	O
aka	O
replacement	O
variables	O
(	O
Digital	O
Research	O
/	O
Novell	O
/	O
Caldera	O
terminology	O
)	O
or	O
batch	O
file	O
parameters	O
(	O
JP	B-Application
Software	I-Application
terminology	O
)	O
%	O
1	O
..	O
%9	O
and	O
%0	O
can	O
be	O
used	O
to	O
retrieve	O
the	O
calling	O
parameters	O
of	O
a	O
batchjob	B-General_Concept
,	O
see	O
SHIFT	O
.	O
</s>
<s>
In	O
batchjobs	B-General_Concept
,	O
they	O
can	O
be	O
retrieved	O
just	O
like	O
environment	O
variables	O
,	O
but	O
are	O
not	O
actually	O
stored	O
in	O
the	O
environment	O
.	O
</s>
<s>
Some	O
command-line	B-Application
processors	O
(	O
like	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
,	O
Multiuser	B-Operating_System
DOS	I-Operating_System
MDOS.COM/TMP.EXE	O
(	O
Terminal	O
Message	O
Process	O
)	O
,	O
JP	B-Application
Software	I-Application
4DOS	I-Application
,	O
4OS2	B-Application
,	O
4NT	B-Application
,	O
Take	B-Application
Command	I-Application
and	O
Windows	B-Application
cmd.exe	B-Device
)	O
support	O
a	O
type	B-Device
of	O
pseudo-environment	O
variables	O
named	O
system	O
information	O
variables	O
(	O
Novell	O
/	O
Caldera	O
terminology	O
)	O
or	O
internal	O
variables	O
(	O
JP	B-Application
Software	I-Application
terminology	O
)	O
,	O
which	O
can	O
be	O
used	O
to	O
retrieve	O
various	O
possibly	O
dynamic	O
,	O
but	O
read-only	O
information	O
about	O
the	O
running	O
system	O
in	O
batch	B-General_Concept
jobs	I-General_Concept
.	O
</s>
<s>
Since	O
they	O
are	O
not	O
stored	O
in	O
the	O
environment	O
,	O
they	O
are	O
not	O
listed	O
by	O
SET	B-Device
and	O
do	O
not	O
exist	O
for	O
external	O
programs	O
to	O
retrieve	O
.	O
</s>
<s>
While	O
almost	O
all	O
such	O
variables	O
are	O
prefixed	O
with	O
an	O
underscore	O
("_"	O
)	O
by	O
4DOS	B-Application
etc	O
.	O
</s>
<s>
%_SECOND%	O
)	O
,	O
they	O
are	O
not	O
under	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
(	O
f.e.	O
</s>
<s>
In	O
addition	O
,	O
4DOS	B-Application
,	O
4OS2	B-Application
,	O
4NT	B-Application
,	O
and	O
Take	B-Application
Command	I-Application
also	O
support	O
so	O
called	O
variable	O
functions	O
,	O
including	O
user-definable	O
ones	O
.	O
</s>
<s>
System	O
information	O
variables	O
supported	O
by	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
:	O
</s>
<s>
The	O
returned	O
string	O
depends	O
on	O
the	O
locale-specific	O
version	O
of	O
DR-DOS	B-Application
,	O
f.e.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
The	O
returned	O
string	O
depends	O
on	O
the	O
locale-specific	O
version	O
of	O
DR-DOS	B-Application
,	O
f.e.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
%ERRORLEVEL%	O
In	O
COMMAND.COM	B-Operating_System
of	O
DR-DOS	B-Application
7.02	O
and	O
higher	O
,	O
this	O
pseudo-variable	O
returns	O
the	O
last	O
error	O
level	O
returned	O
by	O
an	O
external	O
program	O
or	O
the	O
RETURN	O
command	O
,	O
f.e.	O
</s>
<s>
See	O
also	O
the	O
identically	O
named	O
pseudo-variable	O
%ERRORLEVEL%	O
under	O
Windows	B-Application
and	O
the	O
IF	O
ERRORLEVEL	O
conditional	O
command	O
.	O
</s>
<s>
%ERRORLVL%	O
In	O
DR-DOS	B-Application
7.02	O
and	O
higher	O
,	O
this	O
pseudo-variable	O
returns	O
the	O
last	O
error	O
level	O
in	O
a	O
3-digit	O
format	O
with	O
leading	O
zeros	O
,	O
f.e.	O
</s>
<s>
Under	O
Multiuser	B-Operating_System
DOS	I-Operating_System
,	O
this	O
is	O
a	O
true	O
environment	O
variable	O
automatically	O
updated	O
by	O
the	O
shell	B-Device
to	O
the	O
return	O
code	O
of	O
exiting	O
programs	O
.	O
</s>
<s>
See	O
also	O
the	O
related	O
pseudo-variable	O
%ERRORLEVEL%	O
under	O
DR-DOS	B-Application
and	O
the	O
IF	O
ERRORLEVEL	O
command	O
.	O
</s>
<s>
The	O
returned	O
string	O
depends	O
on	O
the	O
locale-specific	O
version	O
of	O
DR-DOS	B-Application
,	O
f.e.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
The	O
returned	O
string	O
depends	O
on	O
the	O
locale-specific	O
version	O
of	O
DR-DOS	B-Application
,	O
f.e.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
%OS_VERSION%	O
This	O
pseudo-variable	O
returns	O
the	O
version	O
of	O
the	O
operating	B-General_Concept
system	I-General_Concept
depending	O
on	O
the	O
current	O
setting	O
of	O
the	O
environment	O
variable	O
%VER%	O
.	O
</s>
<s>
If	O
%VER%	O
is	O
not	O
defined	O
,	O
%OS_VERSION%	O
returns	O
"	O
off	O
"	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
,	O
which	O
may	O
return	O
versions	O
also	O
for	O
non-DR-DOS	O
versions	O
of	O
DOS	B-Device
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
%YEAR%	O
and	O
%_YEAR%	O
Supported	O
since	O
Novell	O
DOS	B-Device
7	O
,	O
the	O
%YEAR%	O
pseudo-variable	O
returns	O
the	O
year	O
of	O
the	O
current	O
date	O
in	O
a	O
4-digit	O
format	O
,	O
f.e.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
DR-DOS	B-Application
7.02	O
and	O
higher	O
added	O
%_YEAR%	O
for	O
compatibility	O
with	O
4DOS	B-Application
,	O
returning	O
the	O
same	O
value	O
.	O
</s>
<s>
%	O
/	O
%	O
In	O
COMMAND.COM	B-Operating_System
of	O
DR-DOS	B-Application
7.02	O
and	O
higher	O
,	O
this	O
pseudo-variable	O
returns	O
the	O
current	O
SwitChar	B-Device
setting	O
of	O
the	O
system	O
,	O
either	O
"	O
/	O
"	O
(	O
DOS	B-Device
style	O
)	O
or	O
"	O
-	O
"	O
(	O
Unix	B-Application
style	O
)	O
.	O
</s>
<s>
See	O
also	O
the	O
related	O
CONFIG.SYS	B-Device
directive	O
SWITCHAR	B-Device
and	O
the	O
environment	O
variable	O
%SWITCHAR%	O
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
See	O
also	O
a	O
similar	O
environment	O
variable	O
%$WIDTH%	O
under	O
DOS	B-Operating_System
Plus	I-Operating_System
.	O
</s>
<s>
%_COUNTRY%	O
This	O
pseudo-variable	O
returns	O
the	O
systems	O
 '	O
current	O
country	B-Device
code	O
(	O
"	O
1	O
"	O
..	O
"	O
65534	O
"	O
)	O
,	O
f.e.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
See	O
also	O
the	O
CONFIG.SYS	B-Device
directive	O
COUNTRY	B-Device
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
See	O
a	O
similar	O
environment	O
variable	O
%$LENGTH%	O
under	O
DOS	B-Operating_System
Plus	I-Operating_System
.	O
</s>
<s>
This	O
variable	O
was	O
originally	O
introduced	O
by	O
4DOS	B-Application
,	O
but	O
also	O
became	O
available	O
with	O
COMMAND.COM	B-Operating_System
since	O
DR-DOS	B-Application
7.02	O
.	O
</s>
<s>
System	O
information	O
variables	O
supported	O
by	O
DR-DOS	B-Application
COMMAND.COM	B-Operating_System
with	O
networking	O
loaded	O
:	O
</s>
<s>
This	O
always	O
worked	O
with	O
NETX	O
,	O
but	O
it	O
will	O
also	O
work	O
with	O
Personal	B-Application
NetWare	I-Application
's	O
ODI/VLM	O
if	O
the	O
current	O
drive	O
is	O
a	O
PNW-mapped	O
drive	O
(	O
otherwise	O
an	O
empty	O
string	O
is	O
returned	O
)	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
The	O
numbers	O
are	O
assigned	O
by	O
the	O
file	O
server	O
and	O
remain	O
static	O
for	O
as	O
long	O
as	O
the	O
IPX	B-Protocol
connection	O
remains	O
established	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
It	O
resembles	O
an	O
identically	O
named	O
identifier	O
variable	O
in	O
Novell	B-Operating_System
NetWare	I-Operating_System
login	O
scripts	O
.	O
</s>
<s>
Dynamic	O
environment	O
variables	O
(	O
also	O
named	O
internal	O
variables	O
or	O
system	O
information	O
variables	O
under	O
DOS	B-Device
)	O
are	O
pseudo-environment	O
variables	O
supported	O
by	O
CMD.EXE	B-Device
when	O
command-line	B-Application
extensions	O
are	O
enabled	O
,	O
and	O
they	O
expand	O
to	O
various	O
discrete	O
values	O
whenever	O
queried	O
,	O
that	O
is	O
,	O
their	O
values	O
can	O
change	O
when	O
queried	O
multiple	O
times	O
even	O
within	O
the	O
same	O
command	O
.	O
</s>
<s>
While	O
they	O
can	O
be	O
used	O
in	O
batch	B-General_Concept
jobs	I-General_Concept
and	O
at	O
the	O
prompt	O
,	O
they	O
are	O
not	O
stored	O
in	O
the	O
environment	O
.	O
</s>
<s>
Consequently	O
,	O
they	O
are	O
neither	O
listed	O
by	O
SET	B-Device
nor	O
do	O
they	O
exist	O
for	O
external	O
programs	O
to	O
read	O
.	O
</s>
<s>
Indirectly	O
,	O
they	O
are	O
also	O
supported	O
under	O
Windows	B-Application
 '	O
COMMAND.COM	B-Operating_System
,	O
which	O
has	O
been	O
modified	O
to	O
internally	O
call	O
CMD.EXE	B-Device
to	O
execute	O
the	O
commands	O
.	O
</s>
<s>
%CD%	O
This	O
pseudo-variable	O
expands	O
to	O
the	O
current	O
directory	O
equivalent	O
to	O
the	O
output	O
of	O
the	O
command	O
CD	B-Application
when	O
called	O
without	O
arguments	O
.	O
</s>
<s>
While	O
a	O
long	O
filename	O
can	O
be	O
returned	O
under	O
CMD.EXE	B-Device
depending	O
on	O
the	O
current	O
directory	O
,	O
the	O
fact	O
that	O
the	O
current	O
directory	O
will	O
always	O
be	O
in	O
8.3	O
format	O
under	O
COMMAND.COM	B-Operating_System
will	O
cause	O
it	O
to	O
return	O
a	O
short	O
filename	O
under	O
COMMAND.COM	B-Operating_System
,	O
even	O
when	O
COMMAND	O
internally	O
calls	O
CMD	B-Device
.	O
</s>
<s>
%CMDCMDLINE%	O
This	O
pseudo-variable	O
expands	O
to	O
the	O
original	O
startup	O
parameters	O
of	O
CMD.EXE	B-Device
,	O
f.e.	O
</s>
<s>
"	O
C:\Windows\system32\cmd.exe	O
 "	O
.	O
</s>
<s>
Under	O
Windows	B-Application
 '	O
COMMAND.COM	B-Operating_System
,	O
this	O
may	O
return	O
something	O
like	O
"	O
C:\Windows\system32\cmd.exe	O
/c	O
...	O
"	O
due	O
to	O
the	O
fact	O
that	O
COMMAND.COM	B-Operating_System
calls	O
CMD.EXE	B-Device
internally	O
.	O
</s>
<s>
%CMDEXTVERSION%	O
This	O
pseudo-variable	O
expands	O
to	O
the	O
version	O
of	O
the	O
command-line	B-Application
extensions	O
of	O
CMD.EXE	B-Device
,	O
if	O
enabled	O
(	O
e.g.	O
</s>
<s>
"	O
1	O
"	O
under	O
Windows	B-Device
NT	I-Device
,	O
"	O
2	O
"	O
under	O
Windows	B-Application
2000	I-Application
and	O
Windows	B-Application
XP	I-Application
)	O
.	O
</s>
<s>
%ERRORLEVEL%	O
This	O
pseudo-variable	O
expands	O
to	O
the	O
last	O
set	B-Device
error	O
level	O
,	O
a	O
value	O
between	O
"	O
0	O
"	O
and	O
"	O
255	O
"	O
(	O
without	O
leading	O
zeros	O
)	O
.	O
</s>
<s>
External	O
commands	O
and	O
some	O
internal	O
commands	O
set	B-Device
error	O
levels	O
upon	O
execution	O
.	O
</s>
<s>
See	O
also	O
the	O
identically	O
named	O
pseudo-variable	O
%ERRORLEVEL%	O
under	O
DR-DOS	B-Application
and	O
the	O
IF	O
ERRORLEVEL	O
command	O
.	O
</s>
<s>
%HIGHESTNUMANODENUMBER%	O
This	O
pseudo-variable	O
returns	O
the	O
number	O
of	O
the	O
highest	O
NUMA	B-Operating_System
node	O
.	O
</s>
<s>
Unix-like	B-Operating_System
shells	O
have	O
similar	O
dynamically	O
generated	O
variables	O
,	O
bash	B-Operating_System
's	O
$RANDOM	O
being	O
a	O
well-known	O
example	O
.	O
</s>
