-When invoked from
-.BR bbc ,
-two special features are enabled:
-First, the
-.B \-scan
-switch directs
-.B msh
-to do a
-.RB \*(lq scan
-.BR unseen \*(rq
-on start\-up if new items are present in the BBoard. This feature is
-best used from
-.BR bbc ,
-which correctly sets the stage. Second, the
-.B mark
-command in
-.B msh
-acts specially when you are reading a
-BBoard, since
-.B msh
-will consult the sequence \*(lqunseen\*(rq in
-determining what messages you have actually read. When
-.B msh
-exits,
-it reports this information to
-.BR bbc .
-In addition, if you give the
-.B mark
-command with no arguments,
-.B msh
-will interpret it as
-.RB \*(lq mark
-.B \-sequence
-.B unseen
-.B \-delete
-.B \-nozero
-.BR all \*(rq
-Hence, to discard
-all of the messages in the current BBoard you're reading, just use the
-.B mark
-command with no arguments.
-.PP
-Normally, the