Unix was developed as a command line interface as was DOS, which followed 12 years later; however, Unix has a much richer vocabulary than DOS. In addition, Unix is case sensitive, whereas DOS as well as Windows, are not. Following is a brief comparison of common commands:

  Command                  Unix   DOS/Windows

  List directory content   ls     dir
  Copy a file              cp     copy
  Delete a file            rm     del
  Rename a file            mv     rename
  Display contents         cat    type
  Print a file             lpr    print
  Check disk space         df     chkdsk
  Change directory         cd     cd