Using the q command tidies up your mailbox:

   -  messages you have read are moved to file called
      mbox in your home directory.
   -  messages you have deleted are removed from your
      mailbox.
   -  any messages that have not been read or deleted are
      retained  in your mailbox and marked as unread.
   -  messages that have been explicitly saved to a file other
      than mbox are deleted.

• Tip ...

• Example