cmd.exe

Command Prompt, also known as cmd.exe or cmd, is the default command-line interpreter for the OS/2, eComStation, ArcaOS, Microsoft Windows (Windows NT family and Windows CE family), and ReactOS operating systems. On Windows CE .NET 4.2, Windows CE 5.0 and Windows Embedded CE 6.0 it is referred to as the Command Processor Shell. Its implementations differ between operating systems, but the behavior and basic set of commands are consistent.

cmd.exe interacts with the user through a command-line interface. On Windows, this interface is implemented through the Win32 console.cmd.exe may take advantage of features available to native programs of its own platform. For example, on OS/2 and Windows, it can use real pipes in command pipelines, allowing both sides of the pipeline to run concurrently. As a result, it is possible to redirect the standard error stream. (COMMAND.COM uses temporary files, and runs the two sides serially, one after the other.)

Multiple commands can be processed in a single command line using the command separator&&.

When using this separator in the Windowscmd.exe, each command must complete successfully for the following commands to execute. For example:

C:\>CommandA && CommandB && CommandC

In the above example,CommandB will only execute ifCommandA completes successfully, and the execution ofCommandC depends on the successful completion ofCommandB. To process subsequent commands even if the previous command produces an error, the command separator& should be used. For example:

C:\>CommandA & CommandB & CommandC

On Windows XP or later, the maximum length of the string that can be used at the command prompt is 8191 (2¹³-1) characters. On earlier versions, such as Windows 2000 or Windows NT 4.0, the maximum length of the string is 2047 (2¹¹-1) characters. This limit includes the command line, individual environment variables that are inherited by other processes, and all environment variable expansions.

Quotation marks are required for the following special characters:

& < > [ ] { } ^ = ; ! ' + , ` ~

and white space.

The following is a list of the Microsoft OS/2 internalcmd.exe commands:

The following list of internal commands is supported bycmd.exe on Windows NT and later:

The following list of commands is supported bycmd.exe on Windows CE .NET 4.2, Windows CE 5.0 and Windows Embedded CE 6.0:

In addition, thenet command is available as an external command stored in\Windows\net.exe.

The ReactOS implementation includes the following internal commands:

On Windows,cmd.exe is mostly compatible withCOMMAND.COM but provides the following extensions over it:

• More detailed error messages than the blanket "Bad command or file name" (in the case of malformed commands) ofCOMMAND.COM. In OS/2, errors are reported in the chosen language of the system, their text being taken from the system message files. TheHELP command can then be issued with the error message number to obtain further information.
• Supports using of arrow keys to scroll through command history. (Under DOS this function was only available under DR DOS (through HISTORY) and later via an external component calledDOSKEY.)
• Adds rotating command-line completion for file and folder paths, where the user can cycle through results for the prefix using theTab ↹, and⇧ Shift+Tab ↹ for reverse direction.
• Treats the caret character (^) as the escape character; the character following it is to be taken literally. There are special characters incmd.exe andCOMMAND.COM 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 SETLOCAL EnableDelayedExpansion, allowing values of variables to be calculated at runtime instead of during parsing of script before execution (Windows 2000 and later), fixing DOS idioms that made using control structures hard and complex. The extensions can be disabled, providing a stricter compatibility mode.

Internal commands have also been improved:

• TheDELTREE command was merged into theRD command, as part of its/S switch.
• SetLocal andEndLocal commands limit the scope of changes to the environment. Changes made to the command line environment afterSetLocal commands are local to the batch file.EndLocal command restores the previous settings.
• TheCall command allows subroutines within batch file. TheCall command inCOMMAND.COM only supports calling external batch files.
• File name parser extensions to theSet command are comparable with C shell.^{[further explanation needed]}
• TheSet command can perform expression evaluation.
• An expansion of theFor command supports parsing files and arbitrary sets in addition to file names.
• The newPushD andPopD commands provide access past navigated paths similar to "forward" and "back" buttons in a web browser or File Explorer.
• The conditionalIF 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.)

• Comparison of command shells
• List of DOS commands
• COMMAND.COM
• PowerShell
• Windows Terminal

• David Moskowitz; David Kerr (1994). OS/2 2.11 Unleashed (2nd ed.). Sams Publishing. ISBN 978-0672304453.
• Stanek, William R. (2008). Windows Command-Line Administrator's Pocket Consultant (2nd ed.). Microsoft Press. ISBN 978-0735622623.

• "Command-line reference A-Z". Microsoft. April 26, 2023.
• "Cmd". Microsoft Windows XP Product Documentation. Microsoft. Archived from the original on September 2, 2011. Retrieved May 24, 2006.
• "Command Prompt: frequently asked questions". windows Help. Microsoft. Archived from the original on April 22, 2015. Retrieved April 20, 2015.
• "An A–Z Index of the Windows CMD command line". SS64.com.
• "Windows CMD.com – Hub of Windows Commands". windowscmd.com. Archived from the original on January 11, 2022. Retrieved January 4, 2022.
• Most important CMD commands in Windows - colorconsole.de