cat: certificate.crt: input file is output file code example
Example: openssl list certificate chain
# List all certificates in CHAINED.pem
openssl crl2pkcs7 -nocrl -certfile CHAINED.pem | openssl pkcs7 -print_certs -text -noout
# List all certificates in CHAINED.pem
openssl crl2pkcs7 -nocrl -certfile CHAINED.pem | openssl pkcs7 -print_certs -text -noout