Create web-app in PHP that checks a set of lists for duplicates

JOB DESCRIPTION: Create a simple web-app that runs on our LAMP based server that parses all the CSV files in a directory and checks for duplicate email addresses. Each CSV file will contain a single column of email addresses. When duplicates are found the user must be notified (on screen) with the following information: (1) The email address (2) The names of all the files containing the email address For example: [login to view URL]@[login to view URL] found in the following files: [login to view URL] (1 occurrence found) [login to view URL] (2 occurrences found) [login to view URL] (1 occurrences found) The user interface must start-up with a web-screen that allows the user to upload CSV files from their local computer and delete CSV files from the server. NOTE: The directory used for this functonalty will always be the same. The path will be fixed and will be something like /home/aadt/csv-files. THE DUPLICATES DO NOT HAVE TO BE REMOVED FROM THE CSV FILE. That task will be done manually. The user-interface has to be functional and tidy and easy to use but it does not have to be pretty. However the HTML/CSS/PHP should be easy to maintain (I will initially test and maintain the code.) Please DO NOT get fancy on me and use a Framework like Zend's. The version of PHP running on our server is 5.1.