Test exim from CLI without "mail" command

If you don't have "mail" on the CLI for whatever, weird (Redhat-based) reasons, circumvent like so:

1. /path/to/exim -v 'user@domain'
2. type a multi-line message here ending with blank line
3. hit ^D to end message and send
4. you should be returned to shell

Taken: http://atmail.com/kb/2008/testing-email-with-exim/