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 &&.[8]
When using this separator in the Windows cmd.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 if CommandA completes successfully, and the execution of CommandC depends on the successful completion of CommandB. To process subsequent commands even if the previous command produces an error, the command separator & should be used.[9] For example:
C:\>CommandA & CommandB & CommandC
OnWindows 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 2000orWindows 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.[10]
On Windows, cmd.exe is mostly compatible with COMMAND.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) of COMMAND.COM. 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. (Under DOS this function was only available under DR DOS (through HISTORY) and later via an external component called DOSKEY.)
Adds rotating command-line completion for file and folder paths, where the user can cycle through results for the prefix using the Tab ↹, 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 in cmd.exe and COMMAND.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.[16] The extensions can be disabled, providing a stricter compatibility mode.
Internal commands have also been improved:
The DELTREE command was merged into the RD command, as part of its /Sswitch.
SetLocal and EndLocal commands limit the scope of changes to the environment. Changes made to the command line environment after SetLocal commands are local to the batch file. EndLocal command restores the previous settings.[17]
The Call command allows subroutines within batch file. The Call command in COMMAND.COM only supports calling external batch files.
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 IF 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 DOSorMS-DOS.)
