It is available in the EFI shell,[1] as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities,[2] or as part of ASCII's MSX-DOS2 Tools for MSX-DOS version 2.

[4][5] In other environments, such as DOS, OS/2, and Microsoft Windows, similar functionality is provided by the dir command.

[9] Unix and Unix-like operating systems maintain the idea of a working directory.

When invoked without arguments, ls lists the files in the working directory.

File names specified explicitly (for example ls .secret) are always listed.