Webmin PostgreSQL Backup Form Help
    The PostgreSQL system user id must have write permission on any 
directory used as a target for any backup.
    Regardless of the backup file format selected, each database 
will be backed up into a single file having the form:
<name>.<extension> where <extension> will be one 
of 'post', 'tar', or 'sql'.
   Commands specified to run before and after backup are triggered 
before and after each database and 
NOT just once before and once after the entire set.