+=item B<--create,-c>
+
+Create a database
+
+=item B<--update,-u>
+
+Update a database; replaces all keys with the values loaded from the
+file, but keeps existing keys which were not replaced
+
+=item B<--dump,-D>
+
+Dump database to stdout
+
+=item B<--include-key,-k>
+
+Output the key as well as the value. (Off by default)
+
+=item B<--reverse>
+
+Map values to a key
+
+=item B<--key-to-itself>
+
+Map the key to itself (On by default in reverse hashes)
+
+=item B<--missing-newline,-n>
+
+If a key doesn't exist in the database, output a newline. (Forced on
+when --include-key set)
+
+=item B<--reverse,-r>
+
+Reverse the database (value looks up keys instead); only useful during
+creation/update
+