Linux & System Administration

Diagram showing static route setup in Linux: term commands (ip route add), network interfaces, gateway, destination networks and example entries to visualize routing table changes.

Isometric 3D render: polished metal shield with etched circuits and cyan core, semi-transparent holo panel with blurred green code, server racks, floating rule tiles and neon paths

Step-by-step guide to install and configure Nginx on Linux: apt or yum install, enable and start service, create server blocks, set document root, adjust firewall, test and restart

Hands editing an SSH config file on laptop, showing secure options: PermitRootLogin no, PubkeyAuthentication yes, strict file permissions, commented notes for audit and compliance.

Illustration showing steps to change a Linux hostname: edit /etc/hostname update /etc/hosts use hostnamectl set-hostname, reboot or restart network services to apply the new name.

Linux environment variables illustrated terminal showing PATH and HOME, export commands; key=value pairs, scope across processes, persistence via .bashrc/.profile and system settings

Image showing how to view and kill background processes: terminal with ps/top output and PIDs, a system monitor highlighting a PID, and using kill or kill -9 safely to terminate it.

Illustration of Linux network interface management comparing ifconfig and ip commands: configuring interfaces, assigning IPs, bringing ifaces up/down, and viewing addresses/routes.

Step-by-step Linux time sync: choose NTP or chrony, install and enable service, configure servers and firewall, verify drift and status, schedule updates, ensure secure, consistent

Guide to enable or disable SELinux on Red Hat systems: check current mode with sestatus, edit /etc/selinux/config to set enforcing/permissive/disabled, reboot or use setenforce now