If running RedHat 7.1, you'll have to build the RPM for the SRC RPM
because the RPMs available from Exim
RPMs were compiled to use an older version of OpenSSL than the one installed
in RH 7.1 : rpm --rebuild exim-3.22-2.src.rpm ; rpm -Uvh /usr/src/redhat/RPMS/i386/exim-3.22-2.i386.rpm
vi /etc/aliases, and set which unpriviledged user should receive mail
intended for root, eg. root: jdoe
If you want unqualified addresses to have a specific domain added instead
of the mailer's FQDN name (eg. jdoe rewritten as jdoe@acme instead of jdoe@mylinux.acme),
edit /etc/exim.conf, and change "qualify_domain" so that
/etc/rc.d/init.d/exim start
echo "Hello, world" | mail -s "Testing Exim" root
su - jdoe
cat /var/spool/mail/jdoe, and check that the above message was saved
into jdoe's mailbox