I've been using ssmtp for a long time to send automatic notifications from all my embedded systems like routers or NASes and also to send anything from a command line to a desired email address. The program is only 8K (whereas mutt is 3.5M) but it can handle secure TLS/SSL connections to SMTP servers. Setup is very easy as only one file has to be adapted. Please read this tutorial to set the ssmtp up.
To make it easier to use I have written a bash script that handles email header creation and adds a simple command line interface:
