While reading the MH FAQ recently posted here I saw:
Subject: Can I append MH messages (ie. +inbox/1) to a UNIX mailbox format file?
From: Using MH-34
Yes, see support/general/packmbox.sh in the distribution. [1.93]
In looking at the mh source tree I have (mh 6.7), I find no
such file packmbox.sh in support/general.
How can I append MH messages to a Unix mailbox format file?