You can test that Exim is working and delivering email messages with the
/path/to/exim -v 'user@domain' message here ^D ( control D )
This will use exim from the command line to create an email
message To: user@domain. After typing the message, use
Control+D to send the EOF (end of file) characters to exim.
Exim will stop receiving input from the command line and
send the message text to user@domain.