Add User

[Anon]

Hi, I want to write a PHP such that i can add an user on Linux Red Hat 6.1 under the "Home" directory. However, I can create the directory for user "xxxx" only but missing an encrypted password. In my Linux, the encrypted password is in MD5 format.
How can i add the encrypted password to that user "xxxx" using PHP?

Thank You for your kind attention