Cmd.exe

, a.k.a. Command Prompt, is a shell program on later versions of Windows, OS/2, eComStation, ArcaOS, and ReactOS. In some versions of Windows it is referred to as the Command Processor Shell. Implementation differs between operating systems, but with significant consistency of behavior and available commands.
Older, related operating systems, DOS and Windows 9x, provided as the shell. replaced in the Windows product line with the introduction of NT. Current versions of Windows include PowerShell as an alternative shell that runs side-by-side with.
The initial version of for Windows NT was developed by Therese Stowell. Windows CE 2.11 was the first embedded Windows release to support a console and a Windows CE version of. The ReactOS implementation of is derived from FreeCOM, the FreeDOS command line interpreter.

Use

Desktop integration

In Windows, the shell is presented in the desktop via Windows Terminal or on older versions via Windows Console.

Concurrent piping

In OS/2 and Windows, the shell supports pipes to allow both sides of a pipeline to run concurrently. As a result, it is possible to redirect the standard error stream. In contrast, uses temporary files, and runs the two sides serially, one after the other.

Command separator

Multiple commands can be included in a single line using the command separator or.
With the separator, a subsequent command is executed even if the previous command indicates an error. In the following example, each of the three commands is executed, one after the other, and regardless of their result code.

>CommandA & CommandB & CommandC

With the separator, a command must complete successfully for the subsequent command to execute. In the following example, only executes if completes successfully, and only executes if also completes successfully.

>CommandA && CommandB && CommandC

Command line limit

The shell limits the length of a command line which includes entered text, individual environment variables that are inherited by other processes, and all environment variable expansions On Windows XP and later, the maximum length is 8191 characters. On earlier versions, such as Windows 2000 or Windows NT 4.0, the maximum length is 2047 characters.

Escaping special characters

The shell reserves the following characters as special: &<>^=;!'+,`~ and whitespace. In some cases, an argument that contains such characters must be enclosed in double quotes to escape from the special character handling. For example:
>echo me & you
me
'you' is not recognized as an internal or external command,
operable program or batch file.
>echo "me & you"
"me & you"

Internal commands

The following sections list internal commands for implementations of the shell on various operating systems.

OS/2

Internal commands in OS/2:

Internal commands in Windows NT and later:

assoc
break
call
cd
chdir
cls
color
copy
date
del
dir
dpath
echo
endlocal
erase
exit
for
ftype
goto
help
if
keys
md
mkdir
mklink
move
path
pause
popd
prompt
pushd
rd
rem
ren
rename
rmdir
set
setlocal
shift
start
time
title
type
ver
verify
vol
Windows CE

Internal commands in Windows CE.NET 4.2, Windows CE 5.0 and Windows Embedded CE 6.0:

attrib
call
cd
chdir
cls
copy
date
del
dir
echo
erase
exit
goto
help
if
md
mkdir
move
path
pause
prompt
pwd
rd
rem
ren
rename
rmdir
set
shift
start
time
title
type

The command is available as an external command.

ReactOS

Internal commands in ReactOS:

?
alias
assoc
beep
call
cd
chdir
choice
cls
color
copy
ctty
date
del
delete
delay
dir
dirs
echo
echos
endlocal
erase
exit
for
free
goto
history
if
memory
md
mkdir
mklink
move
path
pause
popd
prompt
pushd
rd
rmdir
rem
ren
rename
replace
screen
set
setlocal
shift
start
time
timer
title
type
ver
verify
vol
Comparison with COMMAND.COM

On Windows, provides various user experience enhancments as compared to, including:

More detailed error reporting for malformed commands than the generic "Bad command or file name". In OS/2, errors are reported in the chosen language of the system, their text being taken from the system message files. The HELP command can then be issued with the error message number to obtain further information.
Supports using of arrow keys to scroll through command history. With, this functionality was only available in DR DOS and later via an external component called.
Adds rotating command-line completion for file and folder paths, where the user can cycle through results for the prefix using the, and for reverse direction.
Treats the caret character as the escape character; the character following it is to be taken literally. There are special characters in and that are meant to alter the behavior of the command line processor. The caret character forces the command line processor to interpret them literally.
Supports delayed variable expansion with, allowing values of variables to be calculated at runtime instead of during parsing of script before execution, fixing DOS idioms that made using control structures hard and complex. The extensions can be disabled, providing a stricter compatibility mode.
The DELTREE command was merged into the rd command via the switch.
and commands limit the scope of changes to the environment. Changes made to the command line environment after are local to the batch file. restores the previous settings.
The command allows subroutines within batch file. The command only supports calling external batch files.
File name parser extensions to the command are comparable with C shell.
The command can perform expression evaluation.
An expansion of the for command supports parsing files and arbitrary sets in addition to file names.
The new pushd and popd commands provide access past navigated paths similar to forward and back buttons in a web browser or File Explorer.
The conditional command can perform case-insensitive comparisons and numeric equality and inequality comparisons in addition to case-sensitive string comparisons. This was available in DR-DOS, but not in PC DOS or MS-DOS.