Edit a file from a PHP form

I would like to edit a list from a PHP form. Can someone point me to a good tutorial?? I have walked-through a tutorial that showed me how to successfully pull the contents of text file and display the whole contents. I want to view the contents and then edit a specific line of in a list. So, if I have list of employees and their telephone numbers, I'd like to be able to search the contents and display the employees phone number then allow me to edit the phone number and save it back to the list. I know I can do this with MySQL but I need to keep the source data in a text file. Thanks for any suggestions. -Allen umayxa3@donet.com