Linux Reference & Learning Engine
Practical Linux system administration, interactive chmod calculations, bash sandbox, and RHCSA reference guides.
Filesystem Hierarchy
/etc, /var, /home, /usr, /tmp structure
MODULE 02File Permissions & chmod
Octal modes 755/644, user, group, others
MODULE 03Processes & Systemd
ps aux, top, systemctl, journalctl, daemons
MODULE 04Linux Networking
ip addr, ss -tulpn, ping, dig, netstat
MODULE 05SSH & Key Auth
sshd_config, ssh-keygen, ed25519, tunneling
MODULE 06System Security
sudoers, ufw, firewalld, fail2ban, hardening
MODULE 07Containers & Docker
docker run, Dockerfile, docker-compose
MODULE 08RHCSA Cert Prep
Red Hat Enterprise Linux administration
Interactive chmod Permission Visualizer
Toggle octal modes (755, 644, 700, 777) to inspect owner, group, and world rights
Symbolic Mode String
Owner (User)
r (4) + w (2) + x (1)
Group
r (4) + - (0) + x (1)
Others (World)
r (4) + - (0) + x (1)
Browser Terminal Sandbox
Practice running Linux commands in a browser-based educational simulator
Type commands like ls -la, chmod 755 script.sh, pwd, whoami, ps aux...
Linux Command Reference Dictionary
Dense technical documentation for essential Linux binary commands