maildir flags. The ``--keep`` option may be used to settle for
successful message file delivery.
+This command supports the following special exit status code for
+errors most likely to be temporary in nature, e.g. failure to get a
+database write lock.
+
+``75 (EX_TEMPFAIL)``
+ A temporary failure occured; the user is invited to retry.
+
The exit status of the **post-insert** hook does not affect the exit
status of the **insert** command.