Write a php script to minify JS and CSS

I m looking for a a php script that will run on my website one time and it will minify all JS and CSS For example lets say I have JS and CSS under many folders in my website. I ll run [login to view URL] (the freelancer is supposed to create [login to view URL] ) and it will check all the folders of my WP website (may have option to exclude some folders) and 1) create on the same folder a backup of the original JS or CSS file with adding .original extension to the file name 2) minify the JS and CSS files Example Under [login to view URL] or [login to view URL] will be created the [login to view URL] and [login to view URL] as backup of the original [login to view URL] and [login to view URL] and then a new MINIFIED [login to view URL] and [login to view URL] will be placed there to be called when needed. This to be done on each folder on same level and below that the [login to view URL] script should recursively search on its own. being placed for example on [login to view URL] should check only the files and folders under [login to view URL] If placed under [login to view URL] should check all files and folders under [login to view URL] This script is supposed to be used one time or after a theme / plugin update and removed from the site after, NOT EACH TIME THE SITE LOADS (THERE ARE ALREADY PLUGINS FOR THAT)