File Upload

[Navigator]

How do I change the name of a file with the code when somebody tries to upload one to avoid a "that file already exists" error?

[Fou-Lu]

The $_FILES superglobal contains the original name of the file. If one already exists (file_exists() on the file in your directory), do something with the filename to make it unique.
Use that to try some code. Let us know if you have any problems.