Sometimes when working with Informatica, you have to write a shell script or two (or three...). In those scripts, you might need to send an email on failure, etc..
To do this with the standard Linux client, you would use the following syntax:
echo "body of email" | mail -s "subject" to_email@somedomain.com -- -f the_from_email@somedomain.com
The -f is the "from" email address that will appear on the recipients email they receive.
-Tom Nats