blog: add post on how to automate discord webhooks with cron

blog/howto-automate-discord-webhook-cron-2018-03-29.markdown

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+---
+title: How to Automate Discord Message Posting With Webhooks and Cron
+date: 2018-03-29
+---
+
+# How to Automate Discord Message Posting With Webhooks and Cron
+
+Most Linux systems have [`cron`](https://en.wikipedia.org/wiki/Cron) installed to run programs at given intervals. An example usecase would be to install package updates every Monday at 9 am (keep the sysadmins awake!).
+
+Discord lets us post things using [webhooks](https://discordapp.com/developers/docs/resources/webhook). Combining this with cron lets us create automated message posting bots at arbitrary intervals.
+
+## The message posting script
+
+Somewhere on disk, copy down the following script:
+
+```sh
+#!/bin/sh
+# msgpost.sh
+# change MESSAGE, WEBHOOK and USERNAME as makes sense
+# This code is trivial, and not covered by any license or warranty.
+
+# explode on errors
+set -e
+
+MESSAGE='haha memes are funny xD'
+WEBHOOK=https://discordapp.com/api/webhooks/0892379892092/AFkljAoiuj098oKA_98kjlA85jds
+USERNAME=KRONK
+
+curl -X POST \
+     -F "content=${MESSAGE}" \
+     -F "username=${USERNAME}" \
+     "${WEBHOOK}"
+```
+
+Test run it and get a message like this:
+
+![example discord message](https://i.imgur.com/dtjXcei.png)
+
+## How to automate it
+
+To automate it, first open your [`crontab(5)`](http://man7.org/linux/man-pages/man5/crontab.5.html) file:
+
+```console
+$ crontab -e
+```
+
+Then add a crontab entry as such:
+
+```crontab
+# Post this funny message every hour, on the hour
+0 * * * *  sh /path/to/msgpost.sh
+
+# Also valid with some implementations of cron (non-standard)
+@hourly    sh /path/to/msgpost.sh
+```
+
+Then save this with your editor and it will be loaded into the cron daemon. For more information on crontab formats, see [here](https://crontab.guru/).
+
+To run multiple copies of this, create multiple copies of `msgpost.sh` on your drive with multiple crontab entries.
+
+Have fun :)