Dir (command)

In computing,  (directory) is a command in various computer operating systems used for computer file and directory listing. It is one of the basic commands to help navigate the file system. The command is usually implemented as an internal command in the command-line interpreter (shell). On some systems, a more graphical representation of the directory structure can be displayed using the  command.

Implementations
The command is available in the command-line interface (CLI) of the operating systems Digital Research CP/M, MP/M, Intel ISIS-II, iRMX 86, Cromemco CDOS, MetaComCo TRIPOS, DOS, IBM/Toshiba 4690 OS, IBM OS/2, Microsoft Windows, Singularity, Datalight ROM-DOS, ReactOS, GNU, AROS and in the DCL command-line interface used on DEC VMS, RT-11 and RSX-11. It is also supplied with OS/8 as a CUSP (Commonly-Used System Program).

The  command is supported by Tim Paterson's SCP 86-DOS. On MS-DOS, the command is available in versions 1 and later. It is also available in the open source MS-DOS emulator DOSBox. MS-DOS prompts "Abort, Retry, Fail?" after being commanded to list a directory with no diskette in the drive.

The numerical computing environments MATLAB and GNU Octave include a  function with similar functionality.

DOS, Windows, ReactOS
List all files and directories in the current working directory.

List any text files and batch files (filename extension ".txt" or ".bat").

Recursively list all files and directories in the specified directory and any subdirectories, in wide format, pausing after each screen of output. The directory name is enclosed in double-quotes, to prevent it from being interpreted is as two separate command-line options because it contains a whitespace character.

List any NTFS junction points:

Unices
is not a Unix command; Unix has the analogous  command instead. The GNU operating system, however, has a  command that "is equivalent to  ; that is, by default files are listed in columns, sorted vertically, and special characters are represented by backslash escape sequences". Actually, for compatibility reasons, ls produces device-dependent output. The  instruction, unlike , produces device-independent output.