3.8.3.18 -i: specify an SSH private key

The -i option allows you to specify the name of a private key file in *.PPK format which PuTTY will use to authenticate with the server. This option is only meaningful if you are using SSH.

If you are using Pageant, you can also specify a public key file (in RFC 4716 or OpenSSH format) to identify a specific key file to use. (This won't work if you're not running Pageant, of course.)

For general information on public-key authentication, see chapter 8.

This option is equivalent to the ‘Private key file for authentication’ box in the Auth panel of the PuTTY configuration box (see section 4.22.8).