send-email.sh

#!/bin/bash

# This script wraps around ssmtp. It makes a bit easier for me to send emails from cron.
# How to use this script:
# send-email.sh --subject="hello world" --body_file="/path/to/file.txt" --email="kenny@example.com"

# Set PATH
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

function fail() {
    echo "$@" 1>&2
    exit 1
}

# Parse arguments
# https://unix.stackexchange.com/a/204927/466
while [[ $# -gt 0 ]]; do
    case "$1" in
        --email=*)
            email="${1#*=}"
            ;;
        --subject=*)
            subject="${1#*=}"
            ;;
        --body_file=*)
            body_file="${1#*=}"
            [[ ! -f "$body_file" ]] && fail \
                "Error: file \"${body_file}\" does not exist."
            ;;
        *)
            invalid="${1#*=}"
            fail "Error: \"${invalid}\" is an invalid argument."
            ;;
    esac
    shift
done

# Combine the arguments into a message that makes sense to ssmtp and send it.
printf "Subject: %s\n\n%s\n" "$subject" "$(cat $body_file)" | ssmtp "${email}"