Linux

Cheatsheet: bash, redirects, pipes, jobs, history, aliases.

Cheatsheet: chmod, chown, umask, ACL, attributes, find.

Cheatsheet: ps, top, htop, kill, signals, jobs, monitoring.

Cheatsheet: ip command, ss, nftables/iptables, DNS, routes.

Cheatsheet: systemctl, .service files, timers, journalctl, drop-ins.

Cheatsheet: lsblk, mount, fstab, LVM, btrfs/zfs snapshots.

Cheatsheet: user/group management, sudo, ssh keys, password policy.

Cheatsheet: journalctl, rsyslog, logrotate, dmesg, kernel logs.

Cheatsheet: cron syntax, systemd timers, at, anacron.

Cheatsheet: apt, dnf, pacman, apk, brew, snap/flatpak.