[linux]settup passwordliess login

peicheng@TW-PCLIAO:~
$ ssh-copy-id -i ~/.ssh/id_rsa.pub root@renode2
Warning: the RSA host key for 'renode2' differs from the key for the IP address '10.1.191.177'
Offending key for IP in /home/peicheng/.ssh/known_hosts:28
Matching host key in /home/peicheng/.ssh/known_hosts:78
Are you sure you want to continue connecting (yes/no)? yes

peicheng@TW-PCLIAO:~
$ ssh root@renode2
Warning: the RSA host key for 'renode2' differs from the key for the IP address '10.1.191.177'
Offending key for IP in /home/peicheng/.ssh/known_hosts:28
Matching host key in /home/peicheng/.ssh/known_hosts:78
Are you sure you want to continue connecting (yes/no)? yes
Last login: Wed Jul 10 11:54:56 2013 from remaster

rm the line number  28