Keystore file exists but is empty?

I need the SHA 1 fingerprint from my RELEASE key and as I understand the key is generated when I select the option in Android Studio to build a signed release APK and then I get a Keystore.jks file.By following the google documentation I did this command keytool -exportcert -list -v \ -alias <your-key-name> -keystore <path-to-production-keystore>, but this gave me illegal options:/ error so I looked around the net and did this keytool -exportcert -alias freenthrowkey -keystore C:\Users\User\Documents\FreeNthrowkey

and this now gives me this error: keytool error: java.lang.Exception: Keystore file exists, but is empty: C:\Users\User\Documents\FreeNthrowkey

Please if anyone could help me out I would REALLY appreciate it.

Using following commands should give you proper output:

keytool -list -keystore .keystore

If you are looking for a specific alias, you can also specify it in the command:

keytool -list -keystore .keystore -alias foo

Also, to generate signed APK I suggest you to use Android studio itself. Choose "Generate Signed APK" from Build menu of Android studio and follow the steps. It will generate proper keystore at given path.