Simulate the Enter key in Unix with PHP

Hello, I have been trying to get PHP to execute some code to add users to the htpasswd file. So far I have this system ("htpasswd /users/website/.htpasswd jim"); My browser receives the unix data that reads : Adding user jim printed to the browser. Then you are usually prompted for a password in Unix, so the following is the password I want to submit, but how do I tell it to simulate an ENTER key press after each submission of the password. system ("password"); // usually press enter after this system ("password"); // and enter again. I am hoping this will fix the problem. If it is beginning to add the user, then it should work if I can execute the passwords with an ENTER after it as well. YoBro