Pushover makes it easy to get real-time notifications on your Android, iPhone, iPad, and Desktop (Android Wear and Apple Watch, too!)

You can use this shell function anywhere in your script.

Example:

#!/bin/bash

pushmail() {
    APP_TOKEN='auznj8jnj9v7gyuf5qqexx3vyn'
    USER_TOKEN='uest9vme9gthgpk5f5hmeas59'
    TITLE='nagios-alerts'
    MESSAGE="$1"
    curl 'https://api.pushover.net/1/messages.json' -X POST -d "token=$APP_TOKEN&user=$USER_TOKEN&message=\"$MESSAGE\"&title=\"$TITLE\""
}

# call
pushmail "server is down"

Note: you need to update API tokens and title above