sshpass -p 'ssh_password' ssh www.example.org

# ssh neo@192.168.6.1
The authenticity of host '192.168.6.1 (192.168.6.1)' can't be established.
RSA key fingerprint is c9:97:95:2a:5c:6a:2f:ac:e8:ac:94:24:b0:5c:45:8a.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.6.1' (RSA) to the list of known hosts.
neo@192.168.6.1's password: 

[root@centos6]~# sshpass -p 'chen' ssh neo@192.168.6.1
Last login: Wed Nov 13 15:24:50 2013
[neo@NEO ~]$