The rcvpack program isn't used very much. The file, >, mbox, or mmdf (nmh) actions do the same thing more efficiently. For example, both of these entries append the message to a file named autoproc.log in the home directory:
From autoproc > R autoproc.log
From autoproc ^ R "/x/y/rcvpack autoproc.log"
rcvpack is useful on systems with MH before version 6.8,
and the sendmail MTA, if users want to run
msh on new mail. On those
systems, the file or > action is usually set to
write mailboxes in mailbox format. But the MH rcvpack
always uses MMDF format; that's what msh needs. In MH 6.8
and after, slocal supports the mbox action for
writing MMDF format; on those systems, you won't
need rcvpack from a .maildelivery file.
Under nmh, rcvpack has both -mbox and -mmdf options to write mailbox and MMDF formats, respectively.