Ch 15 : Debian Software packages

In this chapter, we’ll explore package management for debian based Linux System ( .deb or Debian software packages). You’ll learn how to use different tools to install, update, and manage software packages. By the end of this chapter, you’ll be able to efficiently manage software on your Linux system.

This post focuses on .deb packages and apt tool for debian based Linux sysems. For other distributions, please refer to Annexure A.

Table of Contents

Summary

Linux software package management on Debian 12 with apt, dpkg, and tools like Synaptic empowers beginners to manage software efficiently. Understanding repositories and branches ensures a stable, secure system.

Introduction: Debian Software Packages

Linux software package management on Debian 12 is streamlined with tools like apt and dpkg. This chapter introduces beginners to installing, updating, and managing software using .deb packages, configuring repositories via /etc/apt/sources.list, and understanding Debian’s release branches. For a broader overview of package management across Linux distributions, see Annexure A.

A .deb package is Debian’s software format, bundling programs, dependencies, and installation scripts, akin to a compressed installer.

Why Learn about Debian Software Packages ?

Effective package management ensures software compatibility, resolves dependencies, and keeps your Debian system secure and up-to-date. Mastering apt and related tools simplifies these tasks for beginners.

Core Tools: `apt` and `dpkg`

apt is the user-friendly front-end for managing packages, while dpkg is the low-level tool that handles .deb files directly.

Using apt for Software Management

apt interacts with repositories to streamline management of debian software packages.

Update package lists:
```
$ sudo apt update
```

Install a package:

$ sudo apt install package_name

Example:

$ sudo apt install tree

Upgrade packages:
```
$ sudo apt upgrade
```
Full system upgrade:
```
$ sudo apt full-upgrade
```
Remove a package:
```
$ sudo apt remove package_name
```
Purge (remove with configs):
```
$ sudo apt purge package_name
```
Search packages:
```
$ apt search keyword
```
Show package info:
```
$ apt show package_name
```
Clean unused packages:
```
$ sudo apt autoremove
```
Clean package cache:
```
$ sudo apt clean
```

Using dpkg

dpkg installs .deb files manually but doesn’t resolve dependencies.

Install .deb file:
```
$ sudo dpkg -i package.deb
```
Remove package:زا> $ sudo dpkg -r package_name
List installed packages:
```
$ dpkg -l
```

Note: Use apt to fix dependency issues after dpkg:

$ sudo apt install -f

Configuring Repositories

The /etc/apt/sources.list file and /etc/apt/sources.list.d/ directory define package sources. A typical entry:

$ cat /etc/apt/sources.list
deb http://deb.debian.org/debian bookworm main contrib non-free

Components:

main: Free software.
contrib: Free software with non-free dependencies.
non-free: Proprietary software.

Warning: Avoid mixing Debian and Ubuntu repositories, as this can cause system instability.

Adding Custom Repositories

Custom repositories provide software unavailable in Debian’s official repos, like the Brave browser.

Example: Add Brave Browser Repository

$ sudo apt install -y curl
$ sudo curl -fsSLo /usr/share/keyrings/brave-browser-archive-keyring.gpg https://brave-browser-apt-release.s3.brave.com/brave-browser-archive-keyring.gpg
$ echo "deb [signed-by=/usr/share/keyrings/brave-browser-archive-keyring.gpg] https://brave-browser-apt-release.s3.brave.com/ stable main" | sudo tee /etc/apt/sources.list.d/brave-browser-release.list
$ sudo apt update
$ sudo apt install brave-browser

Pros: Access unique software, automatic updates.

Cons: Risk of untrusted sources, potential package conflicts.

Tip: Use only trusted repositories (e.g., official Brave site).

Debian Release Branches

Debian offers three branches:

Stable (Bookworm): Reliable, ideal for beginners and servers, but with older software.
Testing (Trixie): Newer software, some bugs, for enthusiasts.
Unstable (Sid): Cutting-edge, risky, for developers.

Recommendation: Stick with Stable for learning Debian 12.

Switching Branches

Edit /etc/apt/sources.list to change branches (e.g., replace “bookworm” with “trixie”), then run:

$ sudo apt update && sudo apt full-upgrade

Caution: Switching to Testing or Unstable may break your system; back up data first.

Graphical and Alternative Tools

Besides apt, Debian supports user-friendly tools for managing debian software pacakges :

aptitude: Text-based interface. Install:
```
$ sudo apt install aptitude
```
Synaptic: Graphical package manager. Install:
```
$ sudo apt install synaptic
```
GNOME Software: Another graphical package manager. To Install:
```
$ sudo apt install gnome-software
```

snap and flatpak offer cross-distro apps but aren’t Debian’s focus. See Annexure A for details.

Practical Examples

Install and run htop:

$ sudo apt install htop
$ htop

Add a repository and install Brave: Use the Brave example above.

Practice Time!

Test your skills:

Install tree and run tree.
Update all packages with apt.
Search for “firefox” and show its info.
Add a custom repository (e.g., Brave) and install its package.
Clean up unused packages and cache.

Try This: Install tree and run tree. Share your output on X with #LinuxCommandLine!

Glossary of Commands, Tools, and Shortcuts

Reference: For detailed documentation, visit Linux Manpages. For package installation, search on Debian APT.

Command/Tool/Shortcut	Description
apt	Manages packages and dependencies.
dpkg	Installs and manages .deb packages.
sources.list	Lists repositories for package downloads.
aptitude	Text-based package management interface.
synaptic	Graphical package manager.
gnome-software	User-friendly software installer.
curl	Downloads files, used for GPG keys.
tee	Writes output to files, used for repository setup.
GPG key	Verifies repository package authenticity.

APT Commands

Command	Description
`apt update`	Updates the package index to ensure you have the latest package information.
`apt upgrade`	Upgrades all packages to their latest versions.
`apt full-upgrade`	Upgrades all packages to their latest versions, including kernel and dependencies.
`apt install <package>`	Installs a new package or upgrades an existing one.
`apt remove <package>`	Removes an installed package.
`apt purge <package>`	Completely removes an installed package, including configuration files.
`apt autoremove`	Removes unnecessary packages that were automatically installed as dependencies.
`apt autoclean`	Removes unnecessary package files from the cache.
`apt clean`	Removes all package files from the cache.
`apt search <package>`	Searches for a package by name or description.
`apt show <package>`	Displays detailed information about a package.
`apt policy <package>`	Displays the policy for a package, including version and priority.
`apt list`	Displays a list of all packages, including their versions and status.
`apt --fix-broken install`	Attempts to fix broken dependencies and install necessary packages.

References

That’s it for Chapter 15 ! You’ve now learned how to use package managers like apt, aptitude, or synaptic to install, update, and manage software on your Linux system. In the next chapter, we’ll dive into productivity tools—tools that make your Linux experience more enjoyable. Until then, practice using package managers to keep your system up to date.

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