Beginner

File management basic

ls, cp, rm, mv, cat

mkdir, rmdir, nano, vi

Filesystem & permission

Filesystem hierarchy

File permissions (rwx)

chmod, chown, chgrp

Hard and soft links

System information

uname, df, du, free

User management

useradd, passwd, sudo

Process management

ps, top, kill, bg, fg, jobs

File archiving

tar, gzip, gunzip

Package management

Package formats (deb, rpm, snap, flatpak)

apt, dnf, pacman

Intermediate

Network configuration

ifconfig, ip, netstat, ss

NetworkManager GUI

nmcli, resolvectl, ping

dig, nslookup, ethtool

Service management

systemctl, journalctl

dmesg, syslog

Hardware management

Ishw, Ispci, dmidecode

modprobe, Ismod

Text & log processing

head, tail, find, xargs

grep, awk, sed, tee

logrotate

Backup automation

cron, systemd-timer

rsync, scp

Security

ssh, keys, sshd_config

ufw, firewalld

setuid/setgid, stickybit

Advanced

Kernel configuration

sysctl customization

/proc & /sys params

System performance

perf, tuned, hdparm

strace, bpftrace

cgroups, namespaces

Automation scripting

bash/python scripting

Ansible, Puppet, Chef

Filesystem internals

EXT4, XFS, Btrfs, ZFS

RAID configuration

LVM configuration

Virtualization

KVM, QEMU, libvirt

Docker, Dockerfile

Advanced Security

SELinux, AppArmor

iptables, nftables

LUKS, dm-crypt, PAM