Install ssl-cert-check by entering the following commands in the terminal:
sudo apt update sudo apt install ssl-cert-check
Description:
proactively handling X.509 certificate expiration
ssl-cert-check is a small shell script which checks digital certificate expiration. It can also check local certificate files and network accessible servers.
Homepage: http://prefetch.net/articles/checkcertificate.html
Version: 3.30-2
Section: universe/net