`scp` like `ssh` has an option `-i`. In SSH that's documented as `-i identity_file`, and I have a file which works with `ssh user@dest -i my.key` to log in to a device without a password. SCP documents the same option as 

> `-i identity_file` Selects the **file** from which the identity
> (private key) for public key authentication is read. This option is
> **directly passed** to ssh(1).

(emphasis mine). This documentation is clearly wrong, because `scp my.file user@dest:/home/user/ -i my.key` fails with

> my.key: Not a directory

No, it's indeed not a directory. Clearly `scp` is not directly passing the argument to `ssh`, it does a check first, and that check in `scp` is probably the wrong way around (give an error if the argument **is** a directory)

Anyway, since `scp -i` is broken, what can I use instead? SCP version is from Debian 10, man page is dated 2018, no `--version` option available