Package Management in Different Linux Distributions

Linux distributions utilize distinct package managers for software installation, updating, and removal. Administrative (root) privileges are required for these operations.

CentOS / RHEL (yum)

The yum package handler is the standard tool for Red Hat-based distributions.

To install a network utility like curl:

sudo yum install curl

To verify if a package is present on the system:

yum list installed | grep curl

Ubuntu / Debian (apt)

Debian-based systems rely on the apt utility for repository management.

Installing the same utility:

sudo apt install curl

Confirming the installation:

dpkg -l | grep curl

Managing Services with Systemctl

systemctl serves as the primary interface to the systemd init system and service manager. It allows administrators to manipulate the runtime state of daemons and system targets.

Core Operations

Using sshd as a concrete example:

Initiate a daemon:

sudo systemctl start sshd

Terminate a daemon:

sudo systemctl stop sshd

Reload configuration or restart:

sudo systemctl restart sshd

Inspect current runtime status:

sudo systemctl status sshd

Boot Persistence

Enable automatic launch at boot time:

sudo systemctl enable sshd

Prevent automatic launch at boot time:

sudo systemctl disable sshd

System Overview

Display all active service units:

systemctl list-units --type=service

Verify the firewall daemon state (CentOS):

sudo systemctl status firewalld

Compatibility Constraints

systemctl only governs processes that possess a registered unit file within the systemd framewokr. Native system daemons are typically pre-rgeistered. Third-party applicasions may require manual unit file creation if they do not automatically deploy one during installation.