VMS Help LIBRARY, /COMPRESS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Recovers space that was occupied by modules deleted from the
    library. When you specify /COMPRESS, LIBRARY creates a new
    library. You can use options to the /COMPRESS qualifier to make
    some specifications in the new version of the library different
    from the original library.

    Format

      /COMPRESS[=(option[,...])]

 option

    An option that alters the size or format of the library,
    overriding the values specified when the library was created.
    You can specify one or more of the following options: BLOCKS:n,
    GLOBALS:n, HISTORY:n, KEEP, KEYSIZE:n, MODULES:n, or VERSION:n.

1 - Example

  $ LIBRARY/COMPRESS=(KEYSIZE:40,MODULES:80)/TEXT SOURCE

      This LIBRARY command creates a new version of the text library
      SOURCE.TLB. Space left after modules were deleted from the old
      version is recovered in the new version. The new version can
      contain up to 80 modules; the maximum length of module names in
      the new version is 40.