Check SSL certificate's expiration

If you ever want to quickly check the expiration date on your HTTPS server’s SSL certificate all you need is OpenSSL , luckily most of your Linux and OSX workstations will already have it installed.

openssl s_client -showcerts -connect ****:443 </dev/null 2>/dev/null \
  | openssl x509 -noout -dates

You should get back a nice and tidy response with a notBefore and a notAfter date:

notBefore=Mar 13 00:00:00 2015 GMT
notAfter=Mar 12 23:59:59 2018 GMT
Linux  OpenSSL  SSL