Standard DOS environment variables

APPEND

DOS 3.3 and above
Used by APPEND

Stores a copy of the appended directory list if APPEND /E is used.

COMSPEC

DOS 2.0 and above
Used by COMMAND.COM

Specifies the location of COMMAND.COM which is used to reload the transient portion.

CONFIG

DOS 6.0 and above
Used by startup menu processing

Specifies the selected menu blockname.

COPYCMD

DOS 6.2 and above
Used by COPY, MOVE and XCOPY

Used to preset the /Y switch for COPY, MOVE and XCOPY commands. If preset /-Y may be to used to override this.

DIRCMD

DOS 5.0 and above
Used by DIR

Used to preset default switches for the DIR command.

NO_SEP

PC DOS 6.3 and above
Used by CHKDSK, DIR, FORMAT and MEM

Used to remove the numeric separators from output.

PATH

DOS 2.0 and above
Used by COMMAND.COM

Specifies the search path for executable files. Many other programs also use PATH.

PROMPT

DOS 2.0 and above
Used by COMMAND.COM

Specifies the command prompt. If this is not set then the default is $N$G except for PC DOS 7 where the default is $P$G.

TEMP

DOS 5.0 and above
Used by COMMAND.COM

Specifies a temporary directory for piped output. Many other programs use TEMP for temporary files though some programs use TMP instead.