cmd

cmd.exe, the command interpreter for Windows, one of the most widely used command-line shells in the world.

But it is not available on Unix-like systems. Why not bring it to Unix to expand the market?

-- ChenPi11

A faithful reimplementation of the Windows cmd.exe command interpreter for Unix.

Born on GNU/Linux, runs on EVERY UNIX-LIKE SYSTEMS

Unfortunately, it does not support Windows and cannot capture the Windows market.

ONLY LIBC and POSIX API required.

README: American English | README: 简体中文 | README: 微软式中文 | README: 八股文

Supported languages

• American English (en_US.UTF-8, default)
• Simplified Chinese (zh_CN.UTF-8)
• Microsoft translated Chinese (zh_MS.UTF-8)
• Classical Chinese (zh_WY.UTF-8)

By setting the LANG, LC_MESSAGES, or LC_ALL environment variable, you can change the language of the cmd shell.

Screenshots

cmd has been verified running on a wide range of operating systems — even classic System V.

Haiku	OpenBSD	PureDarwin
NetBSD	FreeBSD	System V
GNU/Hurd	macOS	MSYS2

Features

• Batch scripting — CALL, GOTO, IF, FOR, SHIFT, %0..%9 expansion, SETLOCAL/ENDLOCAL scoping, and labels.
• Full pipe & redirection support — |, <, >, >>, 2> with cmd.exe precedence rules.
• 40+ builtin commands — ASSOC, COPY, DIR, ECHO, FOR, IF, SET, START, TITLE, TYPE, and more.
• Windows-style environment semantics — case-insensitive %VAR% expansion, %CD%, %DATE%, %TIME%, %ERRORLEVEL%, %CMDCMDLINE%, delayed expansion with /v:on.
• Line editing — bundled linenoise with Emacs bindings, persistent history (~/.cmd_history), and TAB file/directory completion.
• AutoRun support — site-wide/user init scripts from $PREFIX/etc/cmd/AutoRun/, plus AUTOEXEC.BAT for COMMAND.COM.
• Localised UI — English and Simplified Chinese, selected from the LC_ALL / LC_MESSAGES / LANG environment.
• Two personalities — cmd.exe for the standard interpreter and COMMAND.COM with classic MS-DOS AutoExec behaviour.
• No external dependencies — C89, a POSIX.1 libc, and nothing else.

Building

GNU/Linux (GNU Make)

make
make install PREFIX=/usr/local

Generic Unix (including System V)

sh tbuild.sh # uses $CC, defaults to cc.
sh tbuild.sh CC=cc V=0 # quiet build with a specific compiler.
env SYSV=0 ./tbuild.sh # Disable System V portability flags.

The source is STD C89 with no dependencies beyond a POSIX.1-1990 libc. On tbuild.sh adds the portability flags (-DLIBCMD_SYSV=1 and -DLIBCMD_NO_VSNPRINTF=1) — see lsysport.c. Use SYSV=0 can disable -DLIBCMD_SYSV=1.

Usage

cmd [/c|/k] [/s] [/q] [/d] [/a|/u] [/t:{bf|f}]
[/e:{on|off}] [/f:{on|off}] [/v:{on|off}] [string]

Option	Description
/c string	Execute string and exit
/k string	Execute string and remain interactive
/s	Special parsing mode for /c//k (strip outer quotes)
/q	Quiet mode; no banner or prompt
/d	Disable AutoRun scripts
/a	ANSI output (default)
/u	Unicode output
/t:{bf|f}	Set foreground/background colour nibbles, e.g. /t:0f
/e:{on|off}	Enable/disable command extensions
/f:{on|off}	Enable/disable file-name completion
/v:{on|off}	Enable/disable delayed expansion

Builtin Commands

ASSOC BREAK CALL CD / CHDIR CLS
COLOR COPY DATE DEL / ERASE DIR
DOSKEY ECHO ENDLOCAL EXIT FOR
FTYPE GOTO IF MD / MKDIR MKLINK
MOVE PATH PAUSE POPD PROMPT
PUSHD RD / RMDIR REM REN / RENAME SET
SETLOCAL SHIFT START TIME TITLE
TYPE VER VERIFY VOL

Batch Files

Batch files (.bat and .cmd) are fully supported, including CALL, GOTO, IF, FOR, SHIFT, %0..%9 argument expansion, and SETLOCAL/ENDLOCAL scoping. Labels use the colon prefix:

@ECHOOFF
:againECHO Hello, %1SHIFTIFNOT"%~1"==""GOTO again

Pipes and Redirection

| Pipe stdout of the left command to stdin of the right
< file Redirect stdin from file
> file Redirect stdout to file (overwrite)
>> file Redirect stdout to file (append)
2> file Redirect stderr to file

Multiple redirections can be combined on a single command line.

Files

Path	Purpose
~/.cmd_history	Command history (plain text, one command per line)
~/.cmd_assoc	File extension associations (ASSOC / FTYPE)
$PREFIX/etc/cmd/AutoRun/	Scripts executed on startup
AUTOEXEC.BAT	Startup script for COMMAND.COM

Portability

cmd avoids GNU extensions, designated initialisers, and C99 types where possible. Systems without fnmatch(3), settimeofday(2), setpriority(2), or open_memstream(3) are covered by the portability layer in lsysport.c.

License

GNU General Public License version 3 or later — see LICENSE.

Contributing

See CONTRIBUTING.