Text Message Alerting with Discord + Linux

I recently created a simple text message alerting system with Discord bots, a Bash script, and cron. Here is how to do it yourself! My alerting system uses weather.gov to check for weather advisories in the Madison, WI area, and sends alert messages when one is found.

First, create a Discord account, log in, and hit the plus sign in the bottom left hand corner to create your own “server”. A server is a group chat with multiple sub-chats, called channels.

Optionally, within each server channel’s settings menu, you can lock down permissions so that your Discord server is “read-only”. In my setup, I set permissions so that nobody can post in the “general” channel (besides myself and the bot). This keeps spam out of the server, well-meaning or otherwise, so that your Discord server functions only as an alerting system. I also delete all channels allocated by default besides “general”.

Next, within the “general” channel’s settings menu, you can create a webhook. In other words, a bot! You can give your webhook a name and a profile picture.

The “Copy Webhook URL” button will save your webhook’s URL to your clipboard. Note that this URL should be kept secret: anyone who has this URL can make your bot whatever they like!

Next, create a Bash script on your Linux computer. Mine is very simple: it loads a weather.gov forecast webpage for the Madison area and checks for the presence of the word “warning”, “hazard”, or “advisory”. If a dire weather forecast is found, the script tells the bot to fire a message. A simple HTTPS POST request to our webhook URL allows us to command our bot to send a message to its Discord channel.

#!/usr/bin/sh
url='https://forecast.weather.gov/MapClick.php?zoneid=WIZ063&zflg=1'
toalert=$(curl -s "$url" | grep -Ei 'warning|hazard|advisory' | wc -l)
if [ "$toalert" -ge "1" ]
then
    curl -H "Content-Type:application/json" -X POST \
        -d "{\"content\":
        \"There is a weather hazard reported in the Madison area this morning. See $url. Sent at $(date).\"}" \
        'https://discord.com/api/webhooks/560145063066/hyASmEfCTRdSYIbXXsiRfU2854s3XIrD'
fi

Here is what the end result looks like to a Discord user. Anyone who joins your Discord server on their phone will receive notifications by default when your bot sends a message.

Finally, you can fire your invite link to the masses– and your system is live!