Couldn't establish SSH connection: unable to establish master SSH connection: the authenticity of the target host can't be established, the remote host public key is probably not present on the '~/.ssh/known_hosts' file at RDF.pl line 14.

##</code><code>##

  $ssh = Net::OpenSSH->new($host,
           master_opts => [-o => "StrictHostKeyChecking=no"],
           ...);