Chapter 4.  Quick Programming with Scripts and System Daemons

In the previous chapter, we dealt with native compilation and cross-compilation and saw that the C language is actually a must-know for an embedded developer; however, sometimes, it's better to use a script or an already written daemon to quickly solve a problem.

In this chapter, we're going to take a look at some common and useful system tools we can use in an embedded system to constantly execute a controlling/monitoring procedure. These kinds of software are usually called daemon. In Unix terminology, a daemon is a computer program that runs as a background process rather than being under the direct control of an interactive user, so they are perfect to execute a controlling/monitoring procedure. In this scenario, we're going to take a look at some existing daemons ready-to-use and that we can use to implement some repetitive and common tasks.

Then, we will look at how to install and use some common scripting languages in our embedded developer kits and how to solve a simple but real problem by writing the solution in different languages (we'll present PHP, Python, and Bash) in order to show you the differences between them and using a system daemon when required.

As a last step, we're going to show how an embedded developer can write an their own daemon in C or using a scripting language such as PHP, Python, and Bash. As for previous introductory chapters, experienced developers may decide to skip this chapter, but right now, it's should be quite clear that in any case, reading it might be really useful!