perl mhonarc -add -outdir archive.dir -- -
Earl>Actually, for a single message, the "-- -" part should be eliminated.
If not, mhonarc treats stdin as a source of a mailbox (which can
contain separate message and the MSGSEP resource is applicable).
That is very likely the problem.
Should -single be used as in:
perl mhonarc -add -outdir archive.dir -single
Nope. -single tells mhonarc to convert a single message independent of
an archive (i.e. -outdir and -add are not-applicable) and the converted
message goes to stdout. When -add is specified and no input folders
are specified on the command-line, then mhonarc reads from standard
input a single mail message to be added to an archive.