What is the correct function to use for obtaining the current Unix Timestamp in PHP, and how does it differ from now()?

To obtain the current Unix Timestamp in PHP, you should use the time() function. This function returns the current Unix Timestamp, which represents the number of seconds since the Unix Epoch (January 1, 1970). It differs from using now() because now() returns a formatted date and time string, while time() returns the raw Unix Timestamp.

$currentUnixTimestamp = time();
echo $currentUnixTimestamp;