Linux Administration Resources

• The Linux Documentation Project — general Linux technical documentation.
• systemd Documentation — service and system management reference.
• Linux man-pages project — Linux system-call and library documentation.
• SELinux Project Wiki — SELinux resources.
• Your distribution’s current documentation — authoritative source for packages, network configuration, storage tools, and security defaults.

Verify syntax, defaults, and service behavior against the documentation for the exact distribution and release in use.