dbscan - scan a db file and dump the contents
  common options:
    -A, --ascii                    dump as ascii data
    -D, --db-type <dbimpl>         specify db implementaion (may be: bdb or mdb)
    -f, --dbi <filename>           specify db instance
    -R, --raw                      dump as raw data
    -t, --truncate-entry <size>    entry truncate size (bytes)
  entry file options:
    -K, --entry-id <entry_id>      lookup only a specific entry id
  index file options:
    -G, --id-list-min-size <n>     only display index entries with more than <n> ids
    -I, --import file              Import database instance from file.
    -k, --key <key>                lookup only a specific key
    -l, --id-list-max-size <size>  max length of dumped id list
                                  (default 4096; 40 bytes <= size <= 1048576 bytes)
    -n, --show-id-list-lenghts     display ID list lengths
    --remove                       remove database instance
    -r, --show-id-list             display the conents of ID list
    -S, --stats <dbhome>           show statistics
    -X, --export file              export database instance in file
  other options:
    -s, --summary                  summary of index counts
    -L, --list <dbhome>            list all db files
    --do-it                        confirmation flags for destructive actions like --remove or --import
    -h, --help                     display this usage
  sample usages:
    # list the database instances
    dbscan -L /var/lib/dirsrv/slapd-supplier1/db/
    # dump the entry file
    dbscan -f id2entry.db
    # display index keys in cn.db4
    dbscan -f cn.db4
    # display index keys in cn on lmdb
    dbscan -f /var/lib/dirsrv/slapd-supplier1/db/userroot/cn.db
    (Note: Use 'dbscan -L db_home_dir' to get the db instance path)
    # display index keys and the count of entries having the key in mail.db4
    dbscan -r -f mail.db4
    # display index keys and the IDs having more than 20 IDs in sn.db4
    dbscan -r -G 20 -f sn.db4
    # display summary of objectclass.db4
    dbscan -s -f objectclass.db4