system

(PHP 4, PHP 5)

system — Execute an external program and display the output

说明

string system ( string $command [, int &$return_var ] )

system() is just like the C version of the function in that it executes the given command and outputs the result.

The system() call also tries to automatically flush the web server's output buffer after each line of output if PHP is running as a server module.

If you need to execute a command and have all the data from the command passed directly back without any interference, use the passthru() function.

参数

command: The command that will be executed.
return_var: If the return_var argument is present, then the return status of the executed command will be written to this variable.

返回值

Returns the last line of the command output on success, and FALSE on failure.

范例

Example #1 system() example


<?php
echo '<pre>';

// Outputs all the result of shellcommand "ls", and returns
// the last output line into $last_line. Stores the return value
// of the shell command in $retval.
$last_line = system('ls', $retval);

// Printing additional info
echo '
</pre>
<hr />Last line of the output: ' . $last_line . '
<hr />Return value: ' . $retval;
?>