Unix was developed as a command line interface in the early 1970s with a very rich command vocabulary. DOS followed more than a decade later for the IBM PC, and DOS commands migrated to Windows. Although DOS/Windows commands cover the basics, the command set was never as elaborate as Unix. Microsoft later added a more comprehensive command language for Windows (see PowerShell). Linux and Mac Are Unix Based Linux, as well as Mac OS X, are based on Unix and use the same command line syntax (see terminal). Unix text is generally case sensitive, which means "abC" is not the same as "ABc." DOS/Windows text is not however, and "abC" and "ABc" are equal. Following is a brief comparison of common Unix/Linux commands and their DOS/Windows counterparts. FILE/FOLDER OPERATION UNIX DOS/WINDOWS Change ** directory cd cd Create ** directory mkdir mkdir, md Remove ** directory rmdir rmdir, rd List file names ls dir Copy file cp copy Delete file rm del Rename file mv ren Display file contents cat type Print file lpr print ** A "directory" is a folder.