Computer Tips - How do I put mail on hold?

Date: 2010apr21 Product: postfix Q. How do I put mail on hold? A. Put some mail on hold:
postsuper -h <queue-id> postsuper -h ALL
Messages on hold show up with an exclamation mark (!) in the mailq Release mail from being on hold:
postsuper -H <queue-id> postsuper -H ALL