What is a Package Manager in Linux?
On Linux, software is typically built as a package, distributed through repositories, and managed on the end-user’s system through package managers. Each Linux system typically contains thousands of packages, many of which are required dependencies for other packages.
What is Package?
Most software applications designed for Linux or Unix systems are distributed as packages, which are archives that contain the pre-compiled binary software files, installation scripts, configuration files, dependency requirements, and other details about the software.'
Installing package in Ubuntu
Firstly we need to update our system
sudo apt-get updateInstall packages to allow
aptto use a repository over HTTPSsudo apt-get install apt-transport-https ca-certificates curl software-properties-commonAdd Docker’s official GPG key
curl -fsSLhttps://download.docker.com/linux/ubuntu/gpg| sudo apt-key add -Set up the stable repository
sudo add-apt-repository "deb [arch=amd64]https://download.docker.com/linux/ubuntu$(lsb_release -cs) stable"Update the package index again
sudo apt-get updateInstall Docker CE
sudo apt-get install docker-ce
Systemctl and Systemd
Linux operating systems are known for their robustness and versatility, and managing system services is a crucial aspect of maintaining a well-functioning system. With the advent of systemd, a system and service manager for Linux operating systems, the systemctl command has become an essential tool for managing services. In this article, we will explore the intricacies of systemctl and how it can be used to control and monitor system services.
Let's understand with example
Check Docker Service Status ->
sudo systemctl status docker
This command will show you the current status of the Docker service, including whether it is active (running), inactive, or if there are any issues.
This is the output :
If the service is inactive, active with the below command
sudo systemctl start docker
Managing service ->
Starts a service -> sudo systemctl start service-name
Stops a running service -> sudo systemctl stop service-name
Enables a service to start automatically during system boot -> sudo systemctl enable service-name
Disables automatic startup for a service -> sudo systemctl disable service-name
Displays the current status of a service -> sudo systemctl status serice-name
systemctl status docker vs. service docker status ->
systemctl status docker generally provides more detailed and extensive output compared to service docker status
On modern Linux systems, systemctl status docker is typically preferred due to its detailed output and compatibility with the systemd system manager. Use service docker status on older systems or for simpler status checks.