Shell function to test local system mail configuration

testmail.sh

# Shell function to test mail delivery.

# Requirements: Linux, and "sendmail" somewhere in PATH

# Run "testmail <recipient>". This will return a single string, for
# which you can find in the mail log.

testmail () { 
    if [ -n "$1" ]; then
        uuid=$(cat /proc/sys/kernel/random/uuid);
        msgid_domain=$(hostname --fqdn);
        sendmail -oi -t  <<EOF
Subject: test - $uuid
Message-Id: <testmail.$uuid@$msgid_domain>
To: <$1>

Test mail with identifier $uuid

--
Regards,
$LOGNAME
EOF
        exitcode=$?
        if [ "$exitcode" = 0 ];
        then
            echo "$uuid"
        else
            echo "not sent"
        fi
    else
        echo "Usage: testmail <rcpt>"
    fi
    return $exitcode
}