Package Managers of Ubuntu

apt, apt-get and dpkg are Package manager's of Ubuntu Linux.

To check the list of packages available in the repositories

  apt list | grep package-name
  apt-cache pkgnames | grep package-name
  apt-cache search package-name
  apt-file search/find package-name

To list the installed packages of the system

  apt list --installed | grep package-name
  dpk --get-selections

Also you can evaluate the /var/log/apt/history.log file for looking at the history of packages installed.

To get the list of files installed from a particular package

  apt-file list package-name | grep conf$
  dpkg-query -L package-name | grep filename

To update the packages available in the system

  apt-get update
  apt update

To upgrade the packages in the system

  apt-get upgrade
  apt upgrade

To hold a package for the upgrade/update

  apt-mark hold package-name
  echo "package-name    hold" | dpkg --set-selections

To get the details of the packages kept on hold

  apt-mark showhold
  dpkg --get-selections | grep hold

To unhold the package for the system update

  apt-mark unhold
  echo "package-name   install" | dpkg --set-selections

To list the packages installed automatically or manually

  apt-mark showauto
  apt-mark showmanual

To see the list of up-gradable packages in the system

  apt list --upgradable
  apt-get upgrade --dry-run

To remove the packages automatically from the system that are not needed anymore

  apt autoremove
  apt-get autoremove - Remove automatically all unused packages
  apt-get autoclean  - Erase old downloaded archive files
  apt-get clean      - Erase downloaded archive files

To see the list of sources of repositories configured

  apt edit-sources	-- sources file /etc/apt/sources.list.

This gives you information of all available package versions

  apt-cache policy <packageName>

To install a package in the system

  apt install package-name
  apt-get install package-name
  dpkg -i package-name.deb

To erase the package from the system

  apt remove package-name
  apt-get remove package-name  - Remove the package
  apt-get purge package-name   - Remove the package/configuration files

To go for the distribution update

  apt-get dist-upgrade
  do-release-upgrade

To check the package for broken dependencies

  apt-get check package-name

apt-add-repository is a script for adding apt sources.list entries

apt-add-repository <source-line> - The apt repository source line to add. This is one of:

• a complete apt line in quotes,
• a repo url and areas in quotes (areas defaults to'main')
• a PPA shortcut.
• a distro component

To get the changelog information of some package (so we can check for the vulnerability updates viz: CVE)

apt-get changelog package-name | grep -i cve
rpm -q --changelog package-name   - Incase of rpm based distro
aptitude changelog package-name   - Incase of the aptitude pkg manager.