Linux powers 90% of the internet — every server, container, and cloud environment. This course builds genuine Linux mastery from zero: filesystem internals, permissions, processes, shell scripting, systemd, logs, auditd, SELinux/AppArmor, hardening, forensics, and privilege escalation. By the end, you will investigate compromised systems through /proc and audit logs, harden production servers to CIS Benchmark standards, and perform real Linux incident response — skills directly required for Security Engineer, DevSecOps, and Cloud roles.