$ Linux Command

Packages

apt

Manage packages on Debian and Ubuntu systems.

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Additional Notes

apt is the main package-management command used on Debian, Ubuntu, Kali, Linux Mint, and many related distributions. It installs, removes, upgrades, searches, and shows information about software packages.

Packages come from configured repositories. Before installing or upgrading, apt normally needs a fresh package index so it knows the latest available versions.

Syntax

apt [command] [package...]
sudo apt [command] [package...]

Parameters

  • options: Flags that change how apt behaves.
  • package: Package name to install, remove, query, or upgrade.
  • file: Local package file or repository metadata file when the command supports it.

Common Commands

  • update: Refresh package indexes from repositories.
  • upgrade: Upgrade installed packages without removing packages unless necessary.
  • full-upgrade: Upgrade packages and allow dependency changes when needed.
  • install PACKAGE: Install a package.
  • reinstall PACKAGE: Reinstall a package that is already installed.
  • remove PACKAGE: Remove a package but keep many config files.
  • purge PACKAGE: Remove a package and its system config files.
  • autoremove: Remove packages installed as dependencies that are no longer needed.
  • search TERM: Search package names and descriptions.
  • show PACKAGE: Show package details.
  • list --installed: List installed packages.
  • list --upgradeable: List packages with available upgrades.

Examples

sudo apt update

Refresh package information.

sudo apt install nginx

Install nginx.

apt search ripgrep

Search for packages related to ripgrep.

apt show openssh-server

Read package details before installing.

sudo apt upgrade

Upgrade installed packages.

sudo apt remove nginx

Remove a package but leave many configuration files.

sudo apt purge nginx

Remove a package and its system configuration files.

sudo apt autoremove

Remove unused dependency packages.

apt list --upgradeable

Check what can be upgraded before running a full upgrade.

Practical Notes

  • Run sudo apt update before installing if indexes may be stale.
  • apt install and system upgrades usually require sudo.
  • remove and purge are different. Use purge only when you also want system config removed.
  • full-upgrade may remove packages to complete an upgrade. Read the prompt before confirming.
  • Check the autoremove list before accepting it, because it can remove packages you still use.
  • apt is user-friendly for terminals. Scripts often use apt-get because its interface is more stable.
  • A normal successful run exits with status 0; many apt errors use status 100.
  • On Kali and Ubuntu, broken repositories or bad mirrors often show up during apt update.