PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

Using Program Execution Functions
449
Listing 19.7
Continued
// exec(‘dir’, $result);
foreach ($result as $line)
echo “$line\n”;
echo ‘’;
echo ‘’;
///// passthru version
echo ‘’;
// unix
passthru(‘ls -la’) ;
// windows
// passthru(‘dir’);
echo ‘’;
echo ‘’;
///// system version
echo ‘’;
// unix
$result = system(‘ls -la’);
// windows
// $result = system(‘dir’);
echo ‘’;
echo ‘’;
/////backticks version
echo ‘’;
// unix
$result = `ls -al`;
// windows0
// $result = `dir`;
echo $result;
echo ‘’;
? >
You could use one of these approaches as an alternative to the directory-browsing script
you saw earlier. Note that one of the side effects of using external functions is amply
demonstrated by this code:Your code is no longer portable.This script uses Unix commands,
and the code will clearly not run on Windows.
If you plan to include user-submitted data as part of the command you’re going to
execute, you should always run it through the escapeshellcmd() function first.This