Sendmail

cat << EOF | sendmail -t 
Sender: no-reply@chorke.org
From: Sender <from@chorke.org>
Reply-To: Sender <from@chorke.org>
To: To <to@chorke.org>
CC: Cc <cc@chorke.org>
Disposition-Notification-To: to@chorke.org
Subject: Generic Subject

Generic Body
EOF

Knowledge

/usr/sbin/sendmail -t < filename.eml

References

Sending mail from a Bash shell script Sending a mail from a shell script Reply-To header to send emails Sendmail Attachment