cheatsheet for linux create a super fast ram disk mkdir -p /mnt/ram mount -t tmpfs tmpfs /mnt/ram -o size=8192M show ports on which the system listens on ss -tnl detect new hard disk attached without rebooting for host in /sys/class/scsi_host/*; do echo "- - -" | sudo tee $host/scan; ls /dev/sd* ; done nslookup nslookup -port=8053 ns1.lab-net.lan localhost