kali@kali:~$ echo "deb http://http.kali.org/kali kali-rolling main contrib non-free non-free-firmware" | sudo tee /etc/apt/sources.list
kali@kali:~$ echo "deb http://http.kali.org/kali kali-rolling main contrib non-free non-free-firmware" | sudo tee /etc/apt/sources.list