swith to super user ‘root‘, issue this command:
#visudo
add this line to it:
victor ALL=(ALL) NOPASSWD: ALL
‘NOPASSWD‘, as it indicates, lets user to issue sudo commands without entering password! Make this choice with CAUTION!
Ref:linux系统sudo命令详解
原文：http://www.cnblogs.com/victl/p/4496227.html