UNIX Timestamp is time in seconds between January 1, 1970, and any date. PHP "strtotime" can be used for converting date as a string in UNIX Timestamp for that particular date. Date can be particular inside "strtotime", or can be passed to function as variable. String can be written as "31 December, 2009" or as "next Monday," "+2 week" or "now."

• Open blank text document in you favorite text editor.

• Enter "<?php" to start PHP script.

• Enter "echo date('d F\, Y')."\n";" to print current date in format "31 December, 2009."

• Enter "$convert= date('d F Y');" to put current date in "$convert" variable.

• Enter "echo strtotime($convert)."\n";" to print out UNIX Timestamp for today’s date.

• Enter "?>" to exit PHP script.

• Save script using ".php" extension.

• Execute script by entering "php script.php" from command line.