echo "hello world" | mail -s "a subject" someone@somewhere.com
mail -s "Hello world" you@youremailid.com < /home/ubuntu/test.msg

Send file:

mail doesn’t support the sending of attachments, but Mutt does:

echo "Sending an attachment." | mutt -a file.zip -s "attachment" target@email.com

Source:
http://stackoverflow.com/questions/4658283/shell-script-to-send-email