🚀Mastering Linux Package Management🚀

📦 What is a Package?

A package is a bundle of files and metadata. It 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).Think of it as a neatly wrapped gift containing everything needed for a software application to run.

This can include:

Executable files: The main program that runs.
Libraries: Shared code that helps the program to function.
Documentation: Guides and manuals for using the software.
Configuration files: Settings that help the software run correctly.

📦 Examples of Packages:

Application Software: Like a web browser or a game.
System Software: Like utilities for managing files or settings.

📦 What is a Package Manager in Linux?

A Package Manager is like a superhero librarian for your computer. It is a tool which helps you to find, install, update, and remove software packages. Package managers ensure you always have the right version of software and all the necessary dependencies (other software the package needs to run).

🛠️ Popular Package Managers:

APT (Advanced Package Tool): Used in Debian-based systems like Ubuntu.
YUM (Yellow-dog Updater Modified) and DNF: Used in Red Hat-based systems like CentOS and Fedora.
Pacman: Used in Arch Linux.

🛠️ Different Types of Package Managers in Linux

🐧 Debian-based Systems (e.g., Ubuntu)

APT (Advanced Package Tool): The most common package manager for Debian-based distributions.

  sudo apt update     # Update package list
  sudo apt install <package_name>  # Install a package-

🎩 Red Hat-based Systems (e.g., CentOS, Fedora)

YUM (Yellow-dog Updater Modified): Used in older Red Hat-based distributions.

  sudo yum update     # Update package list
  sudo yum install <package_name>  # Install a package

DNF (Dandified YUM): The next-generation / modified version of YUM.

  sudo dnf update     # Update package list
  sudo dnf install <package_name>  # Install a package

🌐 Arch Linux

Pacman: A package manager specifically for Arch Linux.

  sudo pacman -Syu    # Update package list and upgrade all packages
  sudo pacman -S <package_name>  # Install a package

🔧 What is systemctl and systemd?

⚙️ systemd

systemd is a system and service manager for Linux, responsible for initializing the system and managing services and processes. It offers features like parallel service startup, on-demand activation of daemons, and managing system state.

🔄 systemctl

systemctl is the command-line interface used to interact with systemd and to examine and control the state of the “systemd” system and service manager. With systemctl, you can:

Start and stop services.
Enable or disable services at boot.
Check the status of services.

🆚 Differences between systemctl and systemd

systemd: The actual system and service manager.
systemctl: The tool to control and interact with systemd.

📖 Example Commands:

Start a service:
```
  sudo systemctl start <service_name>
```
Stop a service:
```
  sudo systemctl stop <service_name>
```
Check service status:
```
  sudo systemctl status <service_name>
```
Enable a service:
```
  sudo systemctl enable <service_name>
```

Disable a service:

  sudo systemctl disable <service_name>

🐳 Example: Installing Docker with Package Managers

Let's have a look at how to Install Docker using Package Managers.

🐧 On Ubuntu

Update your package list:
```
 sudo apt update
```

Install required packages:

 sudo apt install apt-transport-https ca-certificates curl software-properties-common

Add Docker's official GPG key:

 curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

Set up the Docker repository:

 echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Install Docker:

 sudo apt update
 sudo apt install docker-ce

Verify the installation:
```
 sudo systemctl status docker
```

If the output of this command comes "Service is active / Service is running" means that we have successfully installed Docker.

🎩 On CentOS

Update your package list:
```
 sudo yum update
```