Openssl usefull command

Convert PKCS7 to CRT

openssl pkcs7 -print_certs -in old.p7b -out new.crt

Convert CRT to PEM

openssl x509 -in mycert.crt -out mycert.pem -outform PEM

Read certificate

openssl x509 -noout -text -in <CERTIFICATE>

Read distant certificate

openssl s_client -connect host:port -state -debug