I can use
wget or a similar command line tool to get an HTTPS response from a server.
On Firefox/chrome browser, I can simply download the certificate in pem format through the user interface, then add it to my trust host list.
How can I download the same HTTPS certificate through the Linux command line?
Already answered here
Just use openssl command
openssl s_client -showcerts -connect server.edu:443 </dev/null 2>/dev/null|openssl x509 -outform PEM >mycertfile.pem