Shell cheatsheet

ls -lah            # list files, human sizes
cd -               # previous directory
grep -rn "x" .     # recursive search with line numbers
find . -name "*.log" -mtime -1
tar czf a.tgz dir/ # create archive
du -sh * | sort -h # disk usage
ss -tlnp           # listening TCP sockets
journalctl -u nginx -f
systemctl status sshd