In computing, ls is a command to list computer files and directories in Unix and Unix-like operating systems. It is specified by POSIX and the Single UNIX Specification.

It is available in the EFI shell, as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities, or as part of ASCII's MSX-DOS2 Tools for MSX-DOS version 2.

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

In other environments, such as DOS, OS/2, and Microsoft Windows, similar functionality is provided by the dir command.

As with most utilities the different implementations have different options. Check the documentation provided with the command for correct usage and options.