In simpler words, a package manager is a tool that allows users to install, remove, upgrade, configure, and manage software packages on an operating system. The package manager can be a graphical application like a software center or a command line tool like apt-get or Pacman.
You’ll often find me using the term ‘package’ in tutorials and articles, To understand package manager, you must understand what a package is.
- What is a package?
A package is usually referred to as an application but it could be a GUI application, command line tool, or a software library (required by other software programs). A package is essentially an archive file containing the binary executable, configuration file, and sometimes information about the dependencies.
Different kinds of package managers
Package Managers differ based on the packaging system but the same packaging system may have more than one package manager.
For example, RPM has Yum and DNF package managers. For DEB, you have apt-get, and for Ubuntu "apt" aptitude command line-based package managers
How to install docker and Jenkins in your system from your terminal using package managers
$ sudo apt-get update: To update the package
$ sudo apt install docker.io: To install the Docket
$ systemctl status docker: to check the service status of docker
$ sudo apt-get update: To update the package information
$ sudo apt-get install openjdk-8-jdk: To install the JDK
$ sudo apt-get install Jenkins
systemctl and systemd
systemctl is used to examine and control the state of the “systemd” system and service manager. systemd is a system and service manager for Unix like operating systems(most of the distributions, not all).