# Comparing SSH Private & Public Keys
$ ssh-keygen -l -f id_rsa
2048 SHA256:SIGNATURE cptest@domain.tld (RSA)
$ ssh-keygen -l -f id_rsa.pub
2048 SHA256:SIGNATURE cptest@domain.tld (RSA)
# Compare SIGNATURES to validate matching key pairs.
# CAUTION improper usage of ssh-keygen will overwrite your files.