To answer your questions:
By default, the software tries to establish pre-authenticated connections to
an IMAP server via rsh and possibly ssh. Adding the /norsh switch to any IMAP
mailbox specifier will quell this:
mailutil -verbose transfer "{emax/pop3}" "{imp/norsh}test/"
There is no such thing as "Read-only POP3" access, and an attempt to open a
POP3 session readonly will fail. However, mailutil tries to open the source
readonly in order to avoid altering any flags (especially recent flags).
That's why you got the error.
In the latest imap-2003 development tarball on
ftp://ftp.cac.washington.edu/mail/imap-2003.DEV.tar.Z
there is a -rwcopy flag which will avoid setting readonly. Thus, you can use
the command:
mailutil -verbose -rwcopy transfer "{emax/pop3}" "{imp/norsh}test/"
with a mailutil built with this version.
Finally, since POP3 only has an INBOX, a better means is to use the copy or
move commands instead of transfer. That way avoids the unnecessary attempt to
list source mailboxes which will only return INBOX in POP3. Thus, with the
latest imap-2003, the best thing is:
mailutil -verbose -rwcopy copy "{emax/pop3}" "{imp/norsh}test/INBOX"
In imap-2002, it will work to move (deleting from the source) instead of copy:
mailutil -verbose move "{emax/pop3}" "{imp/norsh}test/INBOX"
