Using curl to send mail via SMTP

smtptest

#!/bin/bash

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at https://mozilla.org/MPL/2.0/.

# Copyright 2014 Brian Bennett

if [[ -n "$TRACE" ]]; then
    export PS4='[\D{%FT%TZ}] ${BASH_SOURCE}:${LINENO}: ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'
    set -o xtrace
fi

usage () {
    printf '%s -f from -t to -s server [ -p port ]\n' "${0##*/}"
    exit $1
}

while getopts ":f:t:s:p" options; do
    case $options in
        f ) from="${OPTARG}" ;;
        t ) to="${OPTARG}" ;;
        s ) server="${OPTARG}" ;;
        p ) port="${OPTARG}" ;;
        h ) usage 0 ;;
        * ) usage 1 ;;
    esac
done

curl -sv --mail-from "${from:?}" --mail-rcpt "${to:?}" -T - "smtp://${server:?}:${port:-25}" << EOF
From: ${from}
To: ${to}
Subject: test message to ${to} from ${from}

Test submission to ${server}.
EOF