Learning Basic Linux Commands – Raspberry Pi Cheat Sheet

Nano is an easy to use text editor that is installed by default in Raspbian distribution and many other Linux distributions.

Using Nano

You can run nano by just typing in nano at the command prompt.

You can use the following commands to edit the OtherFile.txt created in the previous Unit:

pi@raspberry:~ $ cd
pi@raspberry:~ $ nano OtherFile.txt

Nano will follow the path and open that file if it exists. If it does not exist, it’ll start a new buffer with that file name in that directory.

Let’s take a look at the default nano screen:

At the top row, you’ll see the name of the program version number, the name and extension of the file you’re editing, and whether the file has been modified since it was last saved.

Note: If you have a new file that isn’t saved yet, you’ll see “New Buffer.”

Next, you’ll see the contents of your file.

Lastly, the final two rows at the bottom are the shortcut lines (as shown below).

Shortcuts

Program functions are referred to as “shortcuts” in nano, such as saving, quitting, searching, etc. The most common ones are listed at the bottom of the screen (as shown in the preceding Figure), but there are many more that aren’t.

Warning: nano does not use the Shift key in shortcuts. All shortcuts use lowercase letters and unmodified number keys, so Ctrl+G is NOT Ctrl+Shift+G.

Press Ctrl+G to bring up the Help menu and scroll down with your arrow keys to see a list of valid shortcuts.

When you’re done looking at the list, hit Ctrl+X to exit Help menu.

Now let’s say you’re working on your text file and you want to save it and exit nano. This is executed by pressing Ctrl+X.

Nano will ask you if you want to save the changes, you can type:

• Y, then Enter – to save all your changes
• N, then Enter- to cancel any changes

This is a very brief tutorial that shows how to edit a file and save it using the nano program.

The nano is way more powerful and has a lot of shortcuts that you can use to your advantage, but those go beyond what you need to know to complete this course. You can always refer to the official documentation or use the built-in Help menu.

Managing Software on Your Raspberry Pi

When you know your way around the command line, downloading and installing new software on a computer or device running the Linux OS is quite easy and straightforward.

The software comes in what are called packages — software programs that can be downloaded from the Internet and installed simply by typing a command in the prompt.

To download and install these packages, you normally use a package manager, which downloads and installs not only the software you requested, but also all other required software, known as dependencies.

The Raspbian distribution uses a package manager called apt.

To manage your software, you need the authorization of the administrator, whom you already know as the superuser. To do so, type sudo (superuser do) before a command.

Updating and Upgrading

First and foremost, you have to update the list of available package versions that your package manager is aware of. (The package manager keeps such a list in the Raspberry’s file system.) Type the following command:

pi@raspberry:~ $ sudo apt-get update

You need to be connected to the Internet for this command to work. Text scrolls by after you type the command, giving information about the newest listings.

Next, you should update the software, which you can achieve by commanding apt to upgrade. This command upgrades all the packages you’ve installed to their most recent versions:

pi@raspberry:~ $ sudo apt-get upgrade

In terms of wording, the difference between updating and upgrading is subtle, but what they do is quite different (even though they’re usually done together).

sudo apt-get update updates the list of available package versions but doesn’t install or upgrade any of them, whereas sudo apt-get upgradeupdates the packages themselves, checking the list to do so. For that reason, you should always run update before upgrade.

Installing software

To install a package for which you already know the name, you have to type the following command:

pi@raspberry:~ $ sudo apt-get install <desired application name>

Running software

To run programs directly from the prompt, simply type their names, as shown in the following command:

pi@raspberry:~ $ python

This opens the python interpreter that we are going to explore in the next Module.

Removing software

To remove software from your RPi, you resort once more to the apt package manager. Here’s an example:

pi@raspberry:~ $ sudo apt-get remove <desired application name>

This command, however, leaves behind files that are somehow related to the software, such as configuration files and logs. If you don’t intend to use those files in any way, you can remove everything by using purge:

pi@raspberry:~ $ sudo apt-get purge <desired application name>

Do not remove any package that you didn’t install yourself unless you’re absolutely certain that you know what it’s for. It may be a necessary package that comes with the Linux OS, and removing it may lead to a system crash.

Changing the Raspberry Pi Default Settings

pi@raspberry:~ $ sudo raspi-config

pi@raspberry:~ $ sudo poweroff

pi@raspberry:~ $ sudo reboot