What are the benefits of using functions like time() or rand() in PHP for generating unique file names during uploads, and how do they compare in terms of performance and reliability?

When uploading files in PHP, it is important to generate unique file names to prevent conflicts or overwriting existing files. Functions like time() and rand() can be used to create unique file names by appending a timestamp or random number to the original file name. These functions are reliable and efficient for generating unique identifiers quickly.

// Generate a unique file name using time() function
$uniqueFileName = time() . '_' . $_FILES['file']['name'];

// Generate a unique file name using rand() function
$uniqueFileName = rand() . '_' . $_FILES['file']['name'];