php man page for popen

POPEN(3)								 1								  POPEN(3)

popen - Opens process file pointer

SYNOPSIS
       resource popen (string  $command, string  $mode)

DESCRIPTION
	Opens a pipe to a process executed by forking the command given by $command.

PARAMETERS
	      o $command
		- The command

	      o $mode
		- The mode

RETURN VALUES
	Returns  a file pointer identical to that returned by fopen(3), except that it is unidirectional (may only be used for reading or writing)
       and must be closed with pclose(3). This pointer may be used with fgets(3), fgetss(3), and fwrite(3). When the mode  is  'r',  the  returned
       file pointer equals to the STDOUT of the command, when the mode is 'w', the returned file pointer equals to the STDIN of the command.

	If an error occurs, returns FALSE.

EXAMPLES
       Example #1

	      popen(3) example

	      <?php
	      $handle = popen("/bin/ls", "r");
	      ?>

	If  the  command  to  be  executed  could not be found, a valid resource is returned. This may seem odd, but makes sense; it allows you to
       access any error message returned by the shell:

       Example #2

	      popen(3) example

	      <?php
	      error_reporting(E_ALL);

	      /* Add redirection so we can get stderr. */
	      $handle = popen('/path/to/executable 2>&1', 'r');
	      echo "'$handle'; " . gettype($handle) . "
";
	      $read = fread($handle, 2096);
	      echo $read;
	      pclose($handle);
	      ?>

NOTES
       Note

	       If you're looking for bi-directional support (two-way), use proc_open(3).

       Note

	      When safe mode is enabled, you can only execute files within the safe_mode_exec_dir. For practical  reasons,  it	is  currently  not
	      allowed to have .. components in the path to the executable.

       Warning

	      With safe mode enabled, the command string is escaped with escapeshellcmd(3). Thus, echo y | echo x becomes echo y | echo x.

SEE ALSO
       pclose(3), fopen(3), proc_open(3).

PHP Documentation Group 														  POPEN(3)