Checks if a file or directory (or a special file or named pipe on Unix systems) exists. Parameter a specifies the name (including relative or absolute path) of the file. The optional parameters b to e allow further checks.

The function returns true if all checks finished successfully. Parameter c set to true checks if it is allowed to write to the file, b set to true if it is allowed to read from the file. d allows to restrict the type of file to files (f, file, datei) or directories (d, directory, folder, verzeichnis) or a combination of both (d|f). If e is set it will be checked if the file has been changed within a given time. If e is set to a timestamp or date, it is checked if the file has been changed after that time, if e is set to the form now-<milliseconds>, it will be checked if the file has been changed within the last milliseconds as being specified, e.g. now-60000 check for a modification within the last minute.