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. is the counterpart of in DOS and Windows 9x systems, and analogous to the Unix shells used on Unix-like systems. 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. Operation interacts with the user through a command-line interface. On Windows, this interface is implemented through the Win32 console. 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. ( 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 Windows , each command must complete successfully for the following commands to execute. For example: C:\>CommandA && CommandB && CommandC In the above example, will only execute if completes successfully, and the execution of depends on the successful completion of . 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 characters. On earlier versions, such as Windows 2000 or Windows NT 4.0, the maximum length of the string is 2047 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: & < > [ ] { } ^ = ; ! ' + , ` ~ [white space] Internal commands OS/2 The following is a list of the