The previous answers seem all to be a little confusing or incomplete, so here is a table of the differences...

+----------------+-----------------+----------------+----------------+
|    Command     | Displays Output | Can Get Output | Gets Exit Code |
+----------------+-----------------+----------------+----------------+
| system()       | Yes (as text)   | Last line only | Yes            |
| passthru()     | Yes (raw)       | No             | Yes            |
| exec()         | No              | Yes (array)    | Yes            |
| shell_exec()   | No              | Yes (string)   | No             |
| backticks (``) | No              | Yes (string)   | No             |
+----------------+-----------------+----------------+----------------+

• "Displays Output" means it streams the output to the browser (or command line output if running from a command line).
• "Can Get Output" means you can get the output of the command and assign it to a PHP variable.
• The "exit code" is a special value returned by the command (also called the "return status"). Zero usually means it was successful, other values are usually error codes.

Other misc things to be aware of:

• The shell_exec() and the backticks operator do the same thing.
• There are also proc_open() and popen() which allow you to interactively read/write streams with an executing command.
• Add "2>&1" to the command string if you also want to capture/display error messages.
• Use escapeshellcmd() to escape command arguments that may contain problem characters.
• If passing an $output variable to exec() to store the output, if $output isn't empty, it will append the new output to it. So you may need to unset($output) first.

See the readdir examples. It shows how to list directories and files, then you have to get their permissions, owner or other attributes like modification time. Follow the list of filesystem functions and you'll find everything you need

You can do what you want with the following code :

system(command);

See http://php.net/system