Examine generated key file

To examine a generated key file for example the key size enter the following:

openssl rsa -in website.key -check -text

You will get result like this:

Private-Key: (2048 bit)
modulus:
    <cut>
publicExponent: 65537 (0x10001)
privateExponent:
    <cut>
prime1:
    <cut>
prime2:
    <cut>
exponent1:
    <cut>
exponent2:
    <cut>
coefficient:
    <cut>
RSA key ok
writing RSA key
-----BEGIN RSA PRIVATE KEY-----
<cut>
-----END RSA PRIVATE KEY-----