After completing Chapter 1, Getting Started with the BeagleBone Blue , you should have a working BeagleBone Blue running a version of Linux called Ubuntu. We selected this one because it is the most popular and thus has the largest set of supported hardware and software. The commands I am going to review should also work with other versions of Linux, but I'll be showing examples using Ubuntu.

So, power up your BeagleBone Blue, connect via Wi-Fi, and log in to user SSH with the proper username and password. Now you are ready for a quick tour of Linux. This will not be extensive, but you will learn some of the basic commands and how to access some fundamental functionality.

Once you have logged in, you should have an active Terminal window. It should look something like this:

Your cursor...

Now that you can log in and move easily between directories and see which files are in your directories, you'll want to be able to edit those files. To do this, you'll need a program that allows you to edit the characters in a file. If you have worked in Microsoft Windows, you probably have used a program such as Microsoft Notepad, WordPad, or Word to do this. As you might imagine, these are not available in Linux.

There are several choices, all of which are free. I am going to show you how to use an editor program called Emacs. Other possibilities are programs such nano, vi, Vim, and gedit. There is nothing more religious than conversation among programmers about which editor to use, so if you have a strong opinion, you are probably already used to using one of these editors. The vi and nano editors are included...

Now that you can get around and even edit programs, you can begin to use the BeagleBone Blue to create programs so you can control your robotic projects.

Now that you are ready to begin programming, you'll need to choose a language. There are many available: C, C++, Java, Python, Perl, and a great deal of other possibilities. You'll use Python initially for two reasons. First, it is a simple language that makes intuitive sense and is very easy to use. Second, much of the open source functionality in the robotics world is available in Python. You'll also learn a bit of C in this chapter as well because sometimes, functionality is only available in C. But it makes the most sense to start in Python. To work the examples in this section, you'll need a version of Python installed to complete this section...

Now that you know how to run a simple Python program on the BeagleBone Blue, let's look at some more complex programming constructs. Specifically, you'll learn what to do when you want to decide what instructions to execute and show how to loop your code to do the same thing more than once. You'll learn how to use libraries in Python code and how to organize statements into functions. Finally, you'll learn about some very basic object-oriented concepts.

As with the previous section, once you have the basic system and Emacs, you are ready to start coding. As you have seen, your programs normally start with the first line of code and then continue executing the next line until your program runs out of code. This is fine, but what if you want to decide between two different courses of action? You can do...

You've been introduced to a simple programming language in Python. Now let's introduce a more complex but powerful language called C. C is the original language of Linux and has been around for many decades but is still widely used by open source developers. It is similar to Python, but it is also a bit different, and since you may need to both understand and make changes to C code, you may need to be familiar with it and how it is used.

As with Python, you will need to have access to the language capabilities. These come in the form of a compiler and build system, which turns your text files that contain programs to machine code that the processor can actually execute. To do this, type sudo apt-get install build-essential. This will install the programs you need to turn your code into executables for the system.

Now...

It is always a bit difficult to try new things. If this was your first attempt at programming, you may still feel a bit uncomfortable as I ask you to create or edit files. However, I will try to give you explicit instructions on what to type so that you can be successful. There is one major challenge when working with computers. They always do exactly what you tell them to do, not necessarily what you wanted them to do. So if you encounter problems, check several times to make sure that your code matches the example exactly. Now on to the next chapter and some actual coding! In the next chapter, you'll be building a simple wheeled platform that you can control with the BeagleBone Blue.