One of the servers I run has a bit fo a habit of falling over in the middle of the night. I wan't to know about this so I wrote a little script that would test the server and email me if something was wrong. I have extracted the emailing part of the script and present it here:

#!/bin/bash
# Script to send a email

# The subject
SUBJECT="***** The server has crashed *****"

# Who to send the email to
EMAIL="foo@example.com"

# A file to hold the body of the message which
#is later redirected into mail
EMAILMESSAGE="/tmp/server-crashed-message.txt"

#Echo the body of the message into the file. The first line is
#added with > subsequent lines needs to be added with >>
echo "The server is down and needs restarting" > $EMAILMESSAGE

#Send an email using /bin/mail
mail -s "$SUBJECT" "$EMAIL" < $EMAILMESSAGE