Misc linux tools cheatsheet Less Less without line wrapping less -S Colorful less less -r Less: leave uncleared output on exit export LESS="-X" Screen screen -S new_screen_name # create named screen # detach with Ctrl+a, d screen -ls # list screens screen -r 5050 # reattach screen -d -r byname # reattach not-detached session Nmap Check if TCP port is open sudo nmap -sS -p22 192.168.0.50 # SYN scan sudo nmap -sY -p22 192.168.0.50 # open/filtered/closed Discover hosts with ping scan sudo nmap -sP 192.168.0.1/24 Enable Magic Key # Temporary sudo sysctl -w kernel.sysrq=1 # Permanent sudo vim /etc/sysctl.conf # Add: kernel.sysrq=1 GPG Add GPG key to trusted keys (fix NO_PUBKEY) sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys <PUBKEY> Shell Write file without text editor: cat + EOF cat << 'EOF' > task.xml EOF Turn on strict mode in bash set -euxo pipefail
