BeagleBone For Dummies (2015)

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Connecting to your router

Do you ever wonder whether it’s still possible to use a computer without an Internet connection? We can’t recall a time in the past few years that being on a computer without an Internet connection was an enjoyable experience. You can simply connect an Ethernet cable from your home router to the BeagleBone Black. After you’ve made that connection, you can easily install and update software or simply browse the web while using your BeagleBone Black as a desktop computer.

In Figure 12-4, you see an Ethernet cable connected to a BeagleBone Black.

Figure 12-4: Power adapter and Ethernet cable connected to a BeagleBone Black.

Connecting the power

Connecting both a mouse and a keyboard to the BeagleBone Black — as you do in this chapter — can be quite power-consuming, so the power provided by an USB cable may not be sufficient for everything to work smoothly. If you connect your BeagleBone Black via USB to your desktop or laptop computer and everything lights up, great! The BeagleBone Black is getting power. Some functions may be slow or won’t work properly, however. In the worst-case scenario, the peripherals may not even light up. To err on the side of caution, you should get a proper power adapter. That way, you can rest assured that your BeagleBone has all the energy necessary to run at its fullest speed and performance. In Figure 12-4, a 5V power source is connected to a BeagleBone Black.

Make sure your power adapter provides 5V — not more or less than that! Also, you need to ensure that the power adapter has the correct polarity on the jack: The center provides 5V, whereas the outer ring is ground (GND).

Booting up

As soon as you apply power to your BeagleBone Black, it automatically boots. After a few seconds, you should see the typical, awesome-looking beagle with its tongue sticking out as the background of the desktop (see Figure 12-5).

Figure 12-5: First look at your BeagleBone Black’s desktop environment.

If you don’t see anything on the display, try disconnecting everything and then redoing the connections described in the preceding sections. Then reboot your board. Also, if you’re using a TV set as your display, make sure that you change its source to HDMI.

If you can’t see the full image shown in Figure 12-5, or if it’s small in comparison with the screen, the problem has to do with your screen’s adjustment. Try going into your screen’s settings menu and adjusting the picture size until everything fits in a way that’s pleasant to you.

Accessing the Terminal

When you have your BeagleBone Black set up like a desktop computer, you can do all the regular things that you do on a computer — such as creating files and folders or running applications — without using the terminal. If you have the knack of the terminal, however, and know how much faster things can be done that way, you can easily access it.

Even if you prefer doing everything in the desktop environment and using the terminal as little as possible, you still need to use it for some tasks, such as installing and updating software.

To access the terminal, click the icon in the bottom-left corner of your screen. Mouse over to Accessories and click LXTerminal, as shown in Figure 12-6.

You can read more about how to use the Linux terminal in Chapter 4.

Figure 12-6: Opening the terminal.

Figure 12-7 shows an open terminal window. You can have several terminal windows and tabs open at the same time. Click File to generate a new terminal window or tab. You can also see the keyboard shortcuts that do the same things on the menu that appears when you click File.

Figure 12-7: The terminal application window.

During an LXDE session, you may need to resize or minimize your open windows, such as the terminal. You handle this task in much the same way as you would on a Mac or Windows computer.

In this terminal, you can do pretty much the same things you may have done in previous chapters, but here you’re controlling the BeagleBone directly rather than controlling it remotely through the use of SSH. If you’ve created the emailer.py program from Chapter 10, for example, you can run it from the terminal. Start by logging in as root and then changing to the Projects folder:

sudo su
cd /var/lib/cloud9/Projects
python emailing.py

To run the Python script from the terminal, simply type

python emailing.py

Chapter 4 mentions the nano terminal text editor, which you can use to view and edit your text files. When you use your BeagleBone Black to create a desktop environment, you have other text-editor options, such as Leafpad. If you are in the Projects folder, type the following command in the terminal:

leafpad emailing.py

Note that after you issue the command line to start Leafpad, the terminal becomes stuck; you can’t write anything in the terminal from that point on. (Well, you can, but it won’t have any effect.) That’s not a problem because you can have as many open terminal windows and tabs as you want, and only the one where you issued a command to run a program is stuck. Any other open tabs or terminal windows are still functional. When you want to terminate something that’s being run in the terminal, for example Leafpad, simply press Ctrl+C with the terminal window that’s running it open.

Ctrl+C is the Cancel command when you are operating the Terminal. If you need to copy something from the Terminal, the appropriate shortcut is Ctrl+Shift+C. You can use Ctrl+Shift+X for cutting and Ctrl+Shif+V for pasting.

If running the script failed, you probably don’t have the necessary permissions. When you use the BeagleBone as a desktop computer, you’re logged in as debian. Regardless, you can still run programs as root. Don’t forget to log in as root or to precede your commands with sudo:

sudo python /var/lib/cloud9/emailing.py

Roaming the Desktop Environment

Before you start managing files or browsing the web, you need to know how to navigate the environment. This section explains the components of the interface.

Viewing the Applications menu

Click the leftmost icon (the Applications menu) in the bottom-left corner of your screen; it sort of looks like a bird. The Applications menu appears, as shown in Figure 12-6 earlier in this chapter.

The Applications menu is more or less the same as the Windows Start menu. After you’ve installed more programs, other categories should appear, such as Graphics for image-related programs and Programming for tools used to write code. Whenever you mouse over one of these categories, you see a list of applications associated with the category, and you can click a program’s name to run it.

Using the task bar

At the bottom of the screen is a bar known as a panel. Most people, however, would call this the task bar. This bar provides both information and shortcuts for accessing your programs (see Figure 12-8).

Figure 12-8: The task bar.

From left to right, the task bar displays the following things by default:

· Applications menu icon: You can read more about this menu on the previous section.

· Shortcut icons for programs: By default, the two shortcuts are for the File Manager and the web browser, but you can add other shortcuts. This is shown later in this chapter in the “Adding application shortcuts” section.

· Minimize-all button: This button minimizes all the windows that are open on your LXDE session.

· Buttons to change into different desktops: By default, there are two of them. You can read about using multiple desktops in the “Working with multiple desktops” section later in this chapter.

· All programs that you have currently running: Programs that are currently minimized have their names enclosed in brackets. In Figure 12-8, for example, [emailing.py] is a minimized Leafpad window.

· CPU Usage Monitor: The green graph displays the toll that your CPU is taking at the moment. If the CPU is currently hard at work, the rectangle is filled with green. If you just started a processor-heavy program, several peaks show up at the rightmost side. Note that this graph runs from right to left, displaying the newest data on the right.

· Information about network connection: Mousing over this icon provides information regarding your network connection. You can double-click it to manage your available connections.

· Digital clock: The clock displays the current time. When you mouse over the time, the date and day of the week are displayed.

· ScreenLock button: At the time this book was written, that button was buggy and wouldn’t work. When the bugs are fixed, clicking the icon locks the screen so that the screen saver displays and you have to type a password when you want to return to work.

· Logout button: When you click it, a new window opens so you can shut down, reboot, or log out of the current session.

Changing icon settings

Save for the CPU Usage Monitor, you can right-click all icons on the task bar to alter their settings, as you see in Figure 12-9.

Figure 12-9: Changing the settings of an icon on the task bar.

Adding and removing plug-ins

In Figure 12-9 you also see an option to add and remove panel items. When you choose this option, the Panel Preferences dialog box opens (see Figure 12-10). Click the Add button in the Panel Preferences dialog box to see another window that features several plug-ins that you can add to the task bar. To add a plug-in, click the name of the plug-in and then click Add.

Figure 12-10: Adding a plug-in to the task bar.

To remove a plug-in from the task bar, right-click it. You see the menu in Figure 12-9. Click Remove “plug-in name” (where plug-in name is the actual name of the plug-in) from Panel to remove the plug-in.

Adding application shortcuts

It’s important to note that the previous section explains how to add plug-ins not shortcuts for applications. To add an application shortcut, you use the Application Launch Bar plug-in that’s on the task bar by default; it’s next to the Applications menu icon. Follow these steps to add a shortcut icon to the task bar:

1. Right-click the Application Launch Bar plug-in icon, and choose Settings from the shortcut menu.

The Application Launch Bar dialog box opens (see Figure 12-11). On the left side, you see the applications for which you already have shortcuts.

2. From the list on the right side of the Application Launch Bar dialog box, select the application for which you want to create a shortcut.

All applications you currently have on your BeagleBone are listed, separated by category.

3. Click the Add button.

Figure 12-11: Adding a shortcut for an application on the task bar.

Adding task bars

You can add more task bars to your screen. Right-click anywhere on the current task bar and choose Create New Panel from the shortcut menu. A dialog box opens that enables you to choose the new task bar’s position and size. You can also adjust its appearance and designate the plug-ins you want it to feature.

Working with multiple desktops

Linux systems in general allow you to use multiple desktops on the same monitor. Having multiple desktops open is handy for keeping things organized and doing tasks in parallel. There are several ways to change between desktops. For one, you can click the desktop buttons described in the preceding section (refer to Figure 12-8). The blue rectangle is the active desktop. To change to the other one, simply click the gray rectangle.

On the icons for the desktops, the smaller rectangle shows the windows that are open and where on the screen they are. In the case of Figure 12-8, all the windows are in the center of the screen, and the second desktop doesn’t have any window open.

Even if you prefer using a single desktop, it’s good to know about the desktop icons on the task bar. If you unknowingly change from the active desktop to the other desktop, and it looks as though all your work has disappeared in the blink of an eye, just click the other desktop icon to return to the desktop where you were working.

The two desktops are completely independent, so you can customize each one, with different icons on the desktop, different shortcuts, and different themes. You can also have a program running on one desktop but not on the other.

This feature can be really, really useful sometimes. For instance, you could use one desktop for work — featuring programming applications, documentation and a few folders with all your scripts — and another for play — featuring programs for media playing and/or some videogames. If you are working on something that requires both research and development, you could use Desktop 1 for all the websites, datasheets, and any kind of documentation necessary and Desktop 2 for writing the code.

To add a desktop, right-click the Desktop Pager plug-in — that’s where the icons for choosing between each desktop are — and choose Desktop Pager Settings from the shortcut menu. A window opens, in which you can choose the number of desktops and assign them names.

To move a running program from one desktop to the other, simply right-click the application’s title bar and choose Send to Desktop from the shortcut menu. You can choose which desktop you want the application to go to, and you can even send it to all desktops. If you drag the application window to either side of the screen, the application is sent to the next desktop.

You can have as many desktops as you want, but don’t push the BeagleBone too hard. Even though it’s quite powerful for its size, it’s still a system with limited resources.

Customizing the BeagleBone

You use the Preferences tab of the Applications menu to set up the BeagleBone desktop environment in a way that’s comfortable, good-looking, and easy to use.

Customizing the desktop appearance

To customize your desktop, choose Applications⇒Preferences⇒ Openbox Configuration Manager. After a second or two, you see the Openbox Configuration Manager, which includes many customization options (see Figure 12-12).

Figure 12-12: The Openbox Configuration Manager.

With the configuration manager, you can change pretty much every single thing about the appearance of your desktop. Using the Theme tab, you can change the theme to one of the many predefined themes or installing themes that you fetch from the Internet. With the Appearance tab, you can change the font of all text that appears in your windows, such as the title, menu headers, and menu items.

You can also customize your windows, mouse, and the margins of the desktop. With the Desktops tab, you can change the names of your desktops to something that makes more sense.

These examples just scratch the surface of the customization you can do. Play around with the settings on the different tabs until you get the style that you prefer. Don’t worry — it’s impossible to break anything by merely changing its appearance.

Choosing a screen saver

On the Preferences tab, you can choose the Screensaver option to not only change your screen saver, but also define several parameters for it, such as the time it takes for the screen to lock and the time it takes for the screen-saver animation to restart.

You can choose among plenty of screen savers and modes. If you prefer not to use a screen saver, you can disable the feature or just have a blank screen.

Creating icons on the desktop

Apart from that awesome-looking beagle on the desktop, the screen looks kind of bland, doesn’t it? To make your desktop look more like what you may be used to on a typical computer, you can add a few icons for applications, folders, and files that you use frequently.

First, you create shortcuts for applications on your desktop by following these steps:

1. Click the Applications menu icon for in the lower-left corner of your screen.

2. Mouse over to the application you want to have on the desktop and right-click it.

3. Select Add to Desktop as shown in Figure 12-13.

Figure 12-13: Adding shortcuts for applications on the desktop.

In several chapters of this book, you use the Projects folder quite a lot. If you’ve already created it when going through other chapters, then having it on the desktop would be convenient. Normally, you could add a folder to the desktop through standard drag-and-drop or copy-and-paste procedures (similar to what you’d do on a Windows or Mac computer).

Because the Projects folder isn’t below /home/debian, however, you don’t have the necessary permissions to move it around by standard means. Generally, any folder that isn’t below /home/debian has only execute and read permission for users other than the administrator of the system, root, which means that although you can open the folder and see its contents, you can’t edit or move the folder or its contents unless you’re logged in as root. To move the Projects folder, use the following steps:

1. Start the terminal and log in as root, as follows:

sudo su

Keep in mind that you’re logged in as root only in the terminal. Logging in as superuser doesn’t give you root permissions in the desktop environment — only on the command line.

2. Copy the Projects folder to the desktop.

You have to do this recursively because other files are inside the Projects folder. Consequently, you use the -r option:

cp -r /var/lib/cloud9/Projects /home/debian/Desktop

The Projects folder should immediately show up on your desktop. You still don’t have permission to see or change any of the files within it, though.

3. Add read and write permission for all, doing so recursively to the entire folder by typing the following command:

chmod -R a+rw Projects

Some commands use-r for the recursive option, whereas others use -R. The cp and chmod commands used in these steps are good examples. Using the wrong case is often a source of errors.

You should now be able to access and alter any files in your Projects folder within the desktop environment.

To change to the regular user again while you’re in the terminal emulator, type login <username> and then enter a password. The default username is debian, and the default password is temppwd.

If you’re unsure about the concepts of permissions, root and terminal commands, you should check Chapter 4. You can also read how to change the username and password of your BeagleBone’s regular user in Chapter 4.

Changing the desktop background

You can search for backgrounds to download from the Internet. Alternatively, you can use a background from your usual computer by transferring it to the BeagleBone on a USB drive. The "Accessing external storage devices" section explains how to transfer a file from a USB drive. We challenge you to find a desktop background that looks cooler than that dog, though!

After you download or copy the background you want to use, follow these steps to change the background:

1. Right-click any empty spot on the desktop, and choose Desktop Preferences from the shortcut menu.

2. Make your selections for customizing your desktop (see Figure 12-14).

Figure 12-14: The Desktop Preferences dialog box.

Using the File Manager

The File Manager (see Figure 12-15) is the tool you use to manage your files. (Whew, didn’t see that one coming!) Chapter 4 explains how to create directories, rename and copy files, and so on by using command-line options while controlling the BeagleBone remotely through SSH, but you can do those things with a more familiar approach by using the File Manager. If you prefer, you can still use the command line, naturally.

The File Manager bears many striking resemblances to Windows’s File Explorer. You do things such as selecting and copying files in the exact same way. Additionally, most of the keyboard shortcuts available in Windows and Mac OS X are supported by LXDE. The widely known Ctrl+C and Ctrl+V shortcuts are available for copying and pasting files and folders, for example.

Even though using the terminal may seem alien and difficult at first, after you get the gist of it, it greatly speeds the process of managing files. Being a Linux Shell ninja is not about style alone. The terminal really does have several advantages; it just takes a while to get used to it.

Figure 12-15: The LXDE File Manager on the BeagleBone.

You start the File Manager by choosing Applications⇒Accessories or clicking its button in the bottom-left corner of the screen.

Navigating the File Manager

On the right side of Figure 12-15, shown earlier in this chapter, you see all files and folders within the open folder. You open folders and files by double-clicking them. Files open in the default application for that type of file. If Leafpad is your default text editor, for example, a .txt file would open in it.

In some cases, you may want to open a file with a different application. Take an .html file, for example. You would want to open it with a text editor to edit its contents and with your web browser so you can see the actual page. (This type of thing happens a lot in Chapter 15, which introduces HTML.) To open a file with an application other than the default, follow these steps:

1. Right-click the file, and choose Open With from the shortcut menu.

The Choose an Application dialog box opens, enabling you to choose the application you want to use to open the file (see Figure 12-16).

2. Click the application you want to use.

3. If you want this application to be the default application for that type of file, select the Set Selected Application as Default Action of This File Type box at the bottom of the dialog box.

Figure 12-16: Choosing an application to open a file.

On the left side of the File Manager window (refer to Figure 12-15) is the directory tree, which shows the parent folder of the current folder and all the folders above that. The root directory is also shown.