For example, for the website example.com
I know the CA issuer is Digicert. Then
I searched on the /etc/ssl/certs with ls | grep -i digi I got a result like
DigiCert_Assured_ID_Root_CA.pem
DigiCert_Assured_ID_Root_G2.pem
DigiCert_Assured_ID_Root_G3.pem
DigiCert_Global_Root_CA.pem
DigiCert_Global_Root_G2.pem
DigiCert_Global_Root_G3.pem
DigiCert_High_Assurance_EV_Root
How do I know which one is the certificate used for the website example.com