set up a user on centos

Here are some notes to add a user and set up sudo in CentOS:
(1) Create a user ,for example, alice:
useradd alice
passwd alice

(2) Add to the sudo file
visudo
Then add this to the last line:
alice All=(ALL) ALL

(3) ssh-agent

/usr/bin/ssh-agent $SHELL

ssh-add

(4) ssh-agent automatically
sudo yum install openssh-askpass
Main Menu Button (on the Panel) => Preferences => More Preferences =>Sessions, and click on the Startup Programs tab. Click Add and enter /usr/bin/ssh-add in the Startup Command text area