Install packages

Franklin Bristow

Install packages using a package manager on the command line.
- Install packages using a GUI package manager.

Now that you’ve got a running Linux system, you can (and should) use it with the software that’s installed.

You will eventually want or need to install other software that doesn’t come with the distribution by default. While you may need to compile some software from source on Linux to install it, most distributions have a wide variety of software available to be installed using something called a package manager.

A package manager is a program that downloads, installs, and manages “packages”. A package is just another word to describe an application or a piece of software that’s going to be installed on the system.

Debian packages are files with an extension of .deb. A .deb package is kind of the same thing as a .msi file on Windows or a .pkg or .app on macOS.

There are two ways we’re going to install and update packages in Debian: on the command-line and using a GUI.

Administrative users (`root`)

Installing software is an administrative task, and only users that have permissions can install software on a system. Since this is your Linux installation, you are the administrative user and you can install new software.

The main administrator account on Linux and UNIX systems (including macOS!) is called root. Windows users can be administrative users, but there isn’t really a “main” administrator account name.

You may be prompted for an administrative password when managing software on your Linux system. On Debian, the password you should be entering is either the root password you entered during setup, or the same as your user account’s password, depending on which options you selected during install.

Using the Software Center

If you chose Gnome as your desktop environment, Debian has one GUI apps for updating and installing new packages called “Software”.

Make sure that your installation of Debian is completely up to date by installing new updates using Software, then install “Meld Merge”.

On the command line

Installing packages with a GUI is great, but you don’t always have access to a GUI (like when you’re connecting to a remote server with SSH that doesn’t even have a GUI installed), and some packages aren’t listed in the GUI app (notably packages that contain command-line programs). You can also install packages on the command line.

On Debian the command line package manager is apt.

Updating packages on the command line

Updating packages on the command line actually consists of two separate steps:

Updating the lists of available packages.
Updating out-of-date packages.

You use apt to do both of these things:

sudo apt update
sudo apt upgrade

The first time you run a command with sudo you’ll be asked to enter your password. This is the password for your user account.

What the heck is “sudo”?

When you install packages or apps using the GUI in any OS you’re asked to “elevate privileges”: demonstrate that you are an administrative user for this system by entering your password (macOS) or by … clicking a button (Windows).

The sudo command is how you temporarily elevate your privileges on the command line for the command that you want to run.

By default, the sudo command effectively runs the program you’re trying to run as the root user, meaning that the command you’re going to run pretty much has permission to read and write all files on your computer (necessary to install files to system directories).

How the heck do you say “sudo”?

I (me, Franklin) say “Ess-You-Do”, but other people say “Sue-Do”. My preference is “Ess-You” because we’re “Switching User” and running a program. I don’t say “Sue-Do” because I don’t know anybody named Sue.

Running a command with sudo means that it has permission to read and write all files on your computer.

When you’re installing packages, you can generally be confident that the packages the package manager downloads and installs on your computer will not modify your files or important system files.

When you’re getting advice from strangers on the internet, though, you can’t always be confident that what they’re asking you to do will not modify your files or important system files.

Common advice that you read on the internet when something doesn’t work, specifically related to “Permission denied” is “Run it with sudo”. Do not “Run it with sudo”. Instead, stop and ask why you’re getting this error in the first place.

You do not have sudo privileges on public, shared systems like Aviary, so don’t try using sudo on those systems (its use is logged and reported to the administrators who will probably politely ask you to stop).

Installing new packages on the command line

You will almost certainly also want to install new packages on the command line. Installing a package on the command line usually consists of two steps:

Figure out what the name of the package is that you want to install.
Install the package.

Figuring out package names

Sometimes you already know the name of the package that you want to install and you can proceed immediately to step 2, but more often than not you don’t know the name of the package.

There are a few ways to figure out what the name of the package is that you want to install:

Try running the command you want to use on the command line, and your terminal may helpfully tell you what to install:
```
pandoc
```
```
Command 'pandoc' is not found, but can be installed with:
sudo apt install pandoc
```
Search for the name of the program or words related to the program’s name with apt search (you don’t need to use sudo to do this, apt search is not installing new files):
```
apt search tmux
```
```
Sorting... Done
Full Text Search... Done
aerc/stable 0.8.2-1 amd64
  World's Best Email Client
// LOTS MORE
tmux/stable,now 3.5a-3 amd64
  terminal multiplexer
```
You can decode the results above as:
- tmux is the name of the program
- stable is the name of the Debian release this package was made for.
- 3.5a-3 is the version of this package.
- amd64 is the architecture that this package was built for.
Search for what you’re looking for online and have the website tell you what to install.

Installing a package by name

Once you know the name of the package, you can use apt to install it:

sudo apt install tmux

🎉, you just installed a package!

Here are some other packages you can install:

fish # a different shell
make # it's make!
build-essentials # a meta-package including a C compiler

Installing a packages outside of repositories

When you’re installing packages with apt or the GUI, you’re downloading and installing packages that are hosted in the official “repository”. The Debian repositories are… comprehensive. There’s a huge amount of software packaged for Debian in the repositories.

Despite the huge amount of software in the repositories, some software isn’t in the repositories (including some popular software like Google’s Chrome or VS Code). Some software in the repositories is out of date compared to the version you want to install.

You can also install packages with your package manager by downloading a package yourself (e.g., from a project’s web site).

Let’s install a more current version of Pandoc than what’s in Debian’s repositories.

In your Linux system, open your web browser (Firefox is installed by default), navigate to Pandoc’s home page, go to the “Installing” tab, then click on the bug “Download the latest installer” button. This will take you to GitHub. Download the .deb version of Pandoc for your architecture (arm64 for M1 Mac, amd64 for everyone else).

This will download the .deb package to your Downloads folder. You can then either double-click the package and install the package with your GUI, or open your terminal and install the package with apt:

# the `./` is important; you must include the full filename.
# your full filename for pandoc might be different from this one!
sudo apt install ./pandoc-2.19.2-1-amd64.deb

Administrative users (root)