Inspect the cert
$ openssl x509 -in example.org.crt -noout -text
Inspect a RSA Private key:
$ openssl rsa -in example.org.key -noout -text
Inspect a RSA public key:
$ openssl rsa -in example.org.pubkey -pubin -noout -text
Inspect a CSR:
$ openssl req -in oats.csr -noout -text
Inspect a remote cert
openssl s_client -connect {HOSTNAME}:{PORT} -showcerts
Inspect a gpg public key
gpg a4ff2279.asc
Export a gpg private key
gpg --output /tmp/private.pgp --armor --export-secret-key test01@test.com
Export a gpg public key
gpg --output /tmp/public.pgp --armor --export test01@test.com