Command to get ssl certificate pinning from certificate

There is a new certificate in PEM format. How to get from it (using OpenSSL?) a format expected by iOS? (example: [Alamofire/Source/ServerTrustEvaluation.swift](https://github.com/Alamofire/Alamofire/blob/master/Source/ServerTrustEvaluation.swift)) I've tried using something like: openssl x509 -in newcertificate.crt -outform der |openssl dgst -sha256 -binary |openssl enc -base64 But it doesn't generate output like debug in iOS library. I can of course get pinning from debug in library - but I would like to receive the same pinning using OpenSSL command.