Installing Software from the Terminal

Welcome back.

In the previous lesson, you learned about permissions and sudo.

Now we use that power for something useful:

Installing software.

Because clicking “Next, Next, Next, Finish” is fine, but installing software from the terminal feels like ordering tools directly from the command-line universe.

Very efficient.

Slightly dramatic.

What You’ll Learn

In this lesson, you’ll learn:

• what a package manager is;
• how to install software on Arch Linux;
• how to install software on Ubuntu or Debian;
• how to install software on Fedora;
• how to search for packages;
• how to remove packages;
• how to update your system safely.

The Mission

Your mission is simple:

Install a small terminal program, check that it works, and learn how package managers help keep your system organized.

Today we install software.

Not chaos.

Software.

What Is a Package Manager?

A package manager is a tool that installs, updates, and removes software.

Instead of downloading random files from random websites, you ask your Linux system:

“Please install this program properly.”

And the package manager handles:

• downloading the package;
• installing dependencies;
• placing files in the correct locations;
• updating the program later;
• removing it when you no longer need it.

A package manager is like a very organized librarian.

Except instead of books, it manages programs.

And it does not judge your browser tabs.

Probably.

Different Linux Systems, Different Package Managers

Different Linux distributions use different package managers.

Common examples:

Arch Linux     pacman
Ubuntu/Debian  apt
Fedora         dnf

The idea is the same.

The commands are different.

Linux likes variety. Sometimes too much variety. Like a buffet where every table has different rules.

Before Installing: Update Package Information

Before installing software, it is often a good idea to update your package information.

Arch Linux

On Arch Linux, update the whole system with:

sudo pacman -Syu

Important: on Arch, avoid partial upgrades. If you update, update the full system.

Arch is powerful, but it does not enjoy half-finished conversations.

Ubuntu or Debian

On Ubuntu or Debian, first update the package list:

sudo apt update

Then upgrade installed packages:

sudo apt upgrade

Fedora

On Fedora, upgrade the system with:

sudo dnf upgrade

This keeps your installed software up to date.

Install a Program

Let’s install htop.

htop is a terminal program that shows running processes and system usage.

It is like top, but friendlier.

A little dashboard for people who enjoy watching their CPU have feelings.

Arch Linux

sudo pacman -S htop

Ubuntu or Debian

sudo apt install htop

Fedora

sudo dnf install htop

After installation, run it:

htop

To quit htop, press:

q

Yes, again q.

Linux tools love q.

It is the emergency exit of terminal life.

Check If a Program Exists

To check if a command exists, use:

command -v htop

You may see something like:

/usr/bin/htop

That means the command exists.

You can also try:

htop --version

Some programs support --version.

Some do not.

Programs have personalities. Not always pleasant ones.

Search for Packages

Sometimes you do not know the exact package name.

You can search.

Arch Linux

pacman -Ss htop

Ubuntu or Debian

apt search htop

Fedora

dnf search htop

Search helps you find available packages.

This is much better than guessing package names like a wizard throwing pasta at a wall.

Show Package Information

You can also inspect package information.

Arch Linux

pacman -Si htop

For an installed package:

pacman -Qi htop

Ubuntu or Debian

apt show htop

Fedora

dnf info htop

This can show:

• version;
• description;
• dependencies;
• repository;
• installed size.

Useful when you want to know what you are installing before inviting it into your system.

Very polite. Very adult.

Remove a Program

If you no longer need a program, remove it.

Arch Linux

sudo pacman -Rns htop

-Rns removes the package and dependencies that are no longer needed.

Use it with attention.

Ubuntu or Debian

sudo apt remove htop

Then remove unused dependencies:

sudo apt autoremove

Fedora

sudo dnf remove htop

Removing software is normal.

Your system does not need to become a museum of every program you ever tried at 2 a.m.

Install Another Useful Tool

Try installing tree.

tree shows folders and files in a tree structure.

Arch Linux

sudo pacman -S tree

Ubuntu or Debian

sudo apt install tree

Fedora

sudo dnf install tree

Now run:

tree ~/terminal-practice

You may see a nice structure of your practice folder.

Finally, your folders look organized.

At least on the screen.

Your real Downloads folder may still need therapy.

Common Mistakes

Forgetting sudo

This may fail:

pacman -S htop

or:

apt install htop

or:

dnf install htop

Installing software usually needs administrator privileges.

Use:

sudo pacman -S htop

or:

sudo apt install htop

or:

sudo dnf install htop

But remember: sudo is power.

Use it because you need it, not because it looks cool.

Using the Wrong Package Manager

This will not work on Arch:

sudo apt install htop

This will not work on Ubuntu:

sudo pacman -S htop

Use the package manager for your distribution.

Linux is flexible, but not that flexible.

Installing Without Reading

Before confirming installation, read what the package manager says.

It may tell you:

• which packages will be installed;
• which dependencies are needed;
• how much space will be used;
• whether something will be removed.

Do not just press Enter like a tired pigeon.

Read first.

Then press Enter like a professional tired pigeon.

Practice

Install tree.

Arch Linux

sudo pacman -Syu
sudo pacman -S tree
tree --version
tree ~/terminal-practice

Ubuntu or Debian

sudo apt update
sudo apt install tree
tree --version
tree ~/terminal-practice

Fedora

sudo dnf upgrade
sudo dnf install tree
tree --version
tree ~/terminal-practice

Then answer:

1. What is a package manager?
2. Which package manager does Arch Linux use?
3. Which package manager does Ubuntu use?
4. Which package manager does Fedora use?
5. Why do installation commands often need sudo?

Mini Challenge

Install two useful terminal tools:

• htop
• tree

Then:

1. Run htop.
2. Quit htop with q.
3. Run tree ~/terminal-practice.
4. Check where tree is installed with command -v tree.
5. Search for another package using your package manager.

No mouse.

At this point, the mouse is not unemployed.

It is retired.

Summary

Today you learned:

• package managers install, update, search, and remove software;
• Arch Linux uses pacman;
• Ubuntu and Debian use apt;
• Fedora uses dnf;
• sudo is often needed for installing software;
• htop shows running processes;
• tree shows folders in a tree structure;
• you should read package manager output before confirming.

Installing software from the terminal is one of the best Linux skills.

It is fast, clean, and powerful.

Also, it makes you look like you know what you are doing.

Which, after this lesson, is becoming dangerously true.

Next Lesson

In the next lesson, we’ll learn about processes and system monitoring.

We will see what is running, what is using resources, and how to stop programs when they misbehave.

Because sometimes software needs a polite conversation.

And sometimes it needs kill.