It there a command to show how many days certificate you have?

[redo_fr]

Hi.
Try with:

echo | openssl s_client -connect <you server here>:443 2>/dev/null | openssl x509 -noout -dates

Reply example:

notBefore=Feb 22 08:56:00 2016 GMT
notAfter=May 22 08:56:00 2016 GMT