應該用exec才對
<?
$mNdiskUsage=exec("df|grep hda5|awk '{print $5}'");
echo $mNdiskUsage;
?>
Description
string exec ( string $command [, array &$output [, int &$return_var]] )
exec() executes the given command.
See Also
system()
passthru()
escapeshellcmd()
pcntl_exec()
backtick operator