/sys$common/syshlp/helplib.hlb INSTALL, PURGE, Example  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  INSTALL> PURGE

      The command in this example deletes all images except those
      installed with the /NOPURGE qualifier. The image files remain
      unaffected. Writable global sections are written back to disk
      upon their removal as known images.