Package Management

Package managers are tools that automate installing, upgrading, configuring, and removing software. Every major Linux distribution includes a package manager, and understanding how to use it is essential for maintaining your system.

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How Package Management Works

┌─────────────────────────────┐
│     Package Repository       │
│  (remote server with .deb    │
│   or .rpm packages)          │
└──────────────┬──────────────┘
               │  download
               ▼
┌─────────────────────────────┐
│      Package Manager         │
│  (apt, dnf, pacman, etc.)    │
│  - resolves dependencies     │
│  - installs / removes        │
│  - tracks installed packages │
└──────────────┬──────────────┘
               │  install
               ▼
┌─────────────────────────────┐
│       Local System           │
│  /usr/bin, /usr/lib, /etc    │
└─────────────────────────────┘

What a Package Contains

• Binary executables
• Libraries and shared objects
• Configuration files
• Documentation and man pages
• Dependency metadata

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APT — Debian / Ubuntu

apt (Advanced Package Tool) is the package manager for Debian-based distributions.

Essential Commands

sudo apt update                       # refresh package index from repositories
sudo apt upgrade                      # upgrade all installed packages
sudo apt full-upgrade                 # upgrade with dependency resolution changes
sudo apt install nginx                # install a package
sudo apt install nginx=1.24.0-1      # install a specific version
sudo apt remove nginx                 # remove a package (keep config files)
sudo apt purge nginx                  # remove package and its config files
sudo apt autoremove                   # remove unused dependencies
sudo apt search "web server"          # search for packages
sudo apt show nginx                   # show package details
apt list --installed                  # list all installed packages
apt list --upgradable                 # list packages with available upgrades

Repository Management

# Add a third-party repository (PPA)
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt update

# Repository configuration files
/etc/apt/sources.list                  # main repository list
/etc/apt/sources.list.d/              # additional repository files

dpkg — Low-Level Debian Package Tool

sudo dpkg -i package.deb             # install a .deb file
dpkg -l                               # list installed packages
dpkg -L nginx                         # list files installed by a package
dpkg -S /usr/bin/curl                 # find which package owns a file

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DNF / YUM — Fedora / RHEL / CentOS

dnf (Dandified YUM) is the package manager for Red Hat-based distributions. It replaced yum.

Essential Commands

sudo dnf check-update                # check for available updates
sudo dnf upgrade                     # upgrade all packages
sudo dnf install httpd               # install a package
sudo dnf remove httpd                # remove a package
sudo dnf search "web server"         # search for packages
sudo dnf info httpd                  # show package details
dnf list installed                   # list installed packages
sudo dnf autoremove                  # remove unused dependencies
sudo dnf group install "Development Tools"  # install a package group

Repository Management

sudo dnf config-manager --add-repo URL   # add a repository
dnf repolist                              # list enabled repositories
/etc/yum.repos.d/                         # repository configuration directory

rpm — Low-Level RPM Package Tool