I realized that in linux as well as in many programs, one can set http_proxy and https_proxy. I see many guides suggest:
http_proxy = http://host:port https_proxy = https://host:port
I have serveral questions:
How a program determine which proxy, http or https, to connect? I tested in a docker alphine image to find out that wget get https://google.com through http_proxxy. It seems that this doesn't depend on which protocol to use.
What is the meaning of http, https in front of host:port? Does it suggest which protocol to use to connect to the proxy server? As I find out I can actually use http://host:port for https_proxy. Besides, setting without http
http_proxxy = host:port