2.5.4.17 UNSAVE Command
  The UNSAVE command deletes the specified version of a file
  from disk. If you do not specify a file, UNSAVE deletes the
  disk file associated with the program currently in memory.
  If you do not specify a version number, UNSAVE deletes the
  previous version. For example:
  OLD PROG1
  Ready
  UNSAVE
  Ready

  The OLD command copies a program named PROG1.BAS
  from disk to memory. The UNSAVE command deletes the
  program from disk.

  You can delete a BASIC source program other than the
  one in memory by specifying the program name. The fol-
  lowing command deletes the most recent version of the file
  PROG2.BAS:
  UNSAVE PROG2

  To delete a file other than a source program, specify the
  file name and file type. The following command deletes the
  previous version of the object module generated from the
  compilation of PROG2:
  UNSAVE PROG2.OBJ