The following example shows how PURGE deletes all but the highest
       versions of objects in a user's DMU format directory:

       DTR> SHOW ALL
       Domains:
         * FAMILIES;3  * FAMILIES;2   * FAMILIES;1   * OWNERS;2
         * OWNERS;1    * PETS;2       * PETS;1       * PROJECTS;3
         * PROJECTS;2  * PROJECTS;1   * YACHTS;5     * YACHTS;4

       Records:
         * FAMILY_REC;2 * FAMILY_REC;1 * OWNER_RECORD;2 * OWNER_RECORD;1
         * PET_REC;1    * PROJECT_REC;1 * YACHT;2       * YACHT;1

       The default directory is CDD$TOP.DTR$USERS.BELL
       No established collections.
       No ready sources.
       No loaded tables.
       DTR> PURGE
       DTR> SHOW DOMAINS, RECORDS
       Domains:
         * FAMILIES;3   * OWNERS;2     * PETS;2      * PROJECTS;3
         * YACHTS;5
       Records:
         * FAMILY_REC;2 * OWNER_RECORD;2 * PET_REC;1 * PROJECT_REC;1
         * YACHT;2

       DTR>

       The following example shows the error message generated if you
       specify a dictionary directory as the final object in the path
       name. It then shows how PURGE works with the path name and KEEP
       arguments.

       DTR> SHOW DICTIONARY
       The default directory is CDD$TOP.DTR$USERS.BELL

       DTR> PURGE CDD$TOP.DTR$USERS.BELL
       Element "CDD$TOP.DTR$USERS.BELL" is not a Domain, Record, Procedure,
        or Table.
       No objects purged for dictionary element "CDD$TOP.DTR$USERS.BELL".

       DTR> SHOW RECORDS

       Records:
         * FAMILY_REC;4   * FAMILY_REC;3   * FAMILY_REC;2 * FAMILY_REC;1
         * OWNER_RECORD;2 * OWNER_RECORD;1 * PET_REC;1    * PROJECT_REC;1
         * YACHT;2        * YACHT;1

       DTR> PURGE CDD$TOP.DTR$USERS.BELL.FAMILY_REC KEEP=2
       DTR> SHOW RECORDS
       Records:
         * FAMILY_REC;4 * FAMILY_REC;3  * OWNER_RECORD;2 * OWNER_RECORD;1
         * PET_REC;1    * PROJECT_REC;1 * YACHT;2        * YACHT;1

       DTR>