The mkdir (make directory) command in the Unix, DOS, DR FlexOS, IBM OS/2, Microsoft Windows, and ReactOS operating systems is used to make a new directory. It is also available in the EFI shell and in the PHP scripting language. In DOS, OS/2, Windows and ReactOS, the command is often abbreviated to md. The command is analogous to the Stratus OpenVOS create_dir command. MetaComCo TRIPOS and AmigaDOS provide a similar MakeDir command to create new directories. The numerical computing environments MATLAB and GNU Octave include an mkdir function with similar functionality.