...You can use the second argument to set your own mode. exists() checks for the presence of one or more files or directories and returns false if any of them is missing. copy() makes a copy of a single file (use mirror() to copy directories). If the target already exists, the file is copied only if the source modification date is later than the target. This behavior can be overridden by the third boolean argument. touch() sets access and modification time for a file. The current time is used by default. You can set your own with the second argument. The third argument is the access time.