In the previous chapter, we just had a dive through the planning and coding of a Nagios plugin. We studied the bits needed to understand what is a plugin, what is expected from it, and how to integrate it with the monitoring system; and this is because creating a script or program is not just the coding itself: this is the last step of a long and complex workflow.
Now, we will venture into something a bit different, creating a small client to send information to a Slack channel. This will allow us to touch on some new topics, such as JSON, and have a look at how to interact with a cloud-based service. We will not write a fully-fledged client with the capability to read and write, but just the sending bit, since Bash is not the optimal tool to build a whole interactive client. The goal here is to write a tool that we could use to send notifications to a channel...