[marginalia_nu]

I block outgoing ports 80 and 443 quite regularly when I need to get shit done, coding-wise. Takes some getting used to, but it's no major obstacle.

[liberia]

What tool or command do you use to do that?

[marginalia_nu]

iptables. I just run

   $ sudo iptables -A OUTPUT -p tcp --dport 443 -j REJECT
   $ sudo iptables -A OUTPUT -p tcp --dport 80 -j REJECT

To block it, and

   $ sudo iptables --flush

to reset.