mail -s "Subject" "xxxxxxxx@outlook.com" <<< "This is the body"

Dec 29 18:15:28 raspberrypi sendmail[14546]: tBU2FSim014546: from=root, size=232, class=0, nrcpts=1, msgid=<201512300215.tBU2FSim014546@raspberrypi.home>, relay=root@localhost
Dec 29 18:15:28 raspberrypi sm-mta[14547]: tBU2FS3h014547: from=<root@raspberrypi.home>, size=480, class=0, nrcpts=1, msgid=<201512300215.tBU2FSim014546@raspberrypi.home>, proto=ESMTP, daemon=MTA-v4, relay=localhost [127.0.0.1]
Dec 29 18:15:28 raspberrypi sendmail[14546]: tBU2FSim014546: to=xxxxxxx@outlook.com, ctladdr=root (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30232, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (tBU2FS3h014547 Message accepted for delivery)