As well as it could be nice to flush the output, discarding it could be nice in term of memory consumption for long process where output is not needed.

In terms of proc_open descriptors, it consists in :

$nullfile = defined('PHP_WINDOWS_VERSION_BUILD') ? 'NUL' : '/dev/null'; $descriptors = array( 1 => array("file", $nullfile, "a+"), 2 => array("file", $nullfile, "a+"), );