Sometime, when we are working or doing some investigations in our spare time we need to check the dates a web certificate has, especially, the expiration date. Obviously, we can go to our browser, introduce the desired url and with a few clicks check the issued and expiration dates.

But, there is another way more simple, easier and, in case we need it, we can script.

echo | openssl s_client -servername www.google.co.uk -connect www.google.co.uk:443 2>/dev/null | openssl x509 -noout -dates

This simple command gives us the information we want.

I hope it is useful.