How can I change a file's extension using PHP?

Question

How can I change a file\'s extension using PHP?

Ex: photo.jpg to photo.exe

Answer 1

For regex fans, modified version of Thanh Trung's 'preg_replace' solution that will always contain the new extension (so that if you write a file conversion program, you won't accidentally overwrite the source file with the result) would be:

preg_replace('/\.[^.]+$/', '.', $file) . $extension