Re: sftp and key locations

Yes, as others have mentioned, you can share a key using either -i
/path/to/private_key or the -oIdentityFile=/path/to/private_key options to
ssh/sftp.

To clarify what Scott said:
> the key actually identifies the user.

The key does not identify the user, it authenticates the user (instead of
a password - the standard authentication method). What identifies the user
is the username passed from the SSH client. Without specifying it, it uses
the current user but you can specify the user using user@host syntax.


> What's important to understand about this is that on the remote system
> (the SFTP server in this case) everyone using this key will appear to be
> the same user.

You can certainly share an identity key among many users without them
being the same user on the remote end, you just need to have the remote
user install the public key to their ~/.ssh/authorized_keys file. However
in this scenario, it would be as if you let all the users share the same
password. This is quite an unusual scenario and one I wouldn't recommend,
however.

If you communicate with your vendor through the same remote user, then it
can certainly make sense for multiple local users to use the same key,
though.