Package managers:- A package manager is a tool or a way to install, upgrade, and remove software packages on the operating system. It can be GUI(Graphical User-Interpretation or a command-line-tool like apt-get or Pacman

A package is generally referred to as a software library which is going to install on your OS. A package usually contains the binary executable, configuration etc.

What is systemctl and systemd?

Systemd is a system and service manager for Linux operating systems, while systemctl is a command-line utility that interacts with systemd.

Here's a simpler difference between the two:

1. Systemd: Systemd is an init system and service manager that provides a way to manage the startup and management of processes, services, and daemons on a Linux system. It is responsible for controlling the entire system initialization process, including starting, stopping, and managing services.

2. Systemctl: systemctl is a command-line utility used to control and manage the system and service manager. It provides a simple interface to interact with systemd, allowing users to start, stop, restart, enable, disable, and check the status of services.

In summary, systemd is the underlying system and service manager, while systemctl is the tool used to interact with and manage systems.

systemctl vs Service

systemctl is the more modern and feature-rich utility for managing services on systems that use systemd, while service is a simpler command that can handle basic service management tasks and is compatible with both systemd and traditional init systems. If your system uses systemd, it is recommended to use systemctl for better functionality and integration.