4 Help: Private key file name
6 Private key file name. Allows you to provide your private key in this separate
7 file. For SSH, if not specified, curl tries the following candidates in order:
8 '~/.ssh/id_rsa', '~/.ssh/id_dsa', './id_rsa', './id_dsa'.
10 If this option is used several times, the last one will be used.