scp: a way to disable password authentication?

[Vincent Lefevre <vincent@vinc17.org>]

I would like to know how I can disable password authentication for scp
(on the client side), i.e. I want to connect by RSA authentication only,
and if this is not possible, I want scp to fail.

The reason is that scp is called from a perl script, and if a password
is required[*], the script hangs until a password is given.

[*] This should never happen, but in the reality, the ssh server isn't
reliable (probably a NFS problem, which means that the RSA public key
can't be read).

Thanks in advance for any information,

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