popen

(PHP 4, PHP 5)

popenOpens process file pointer

Description

resource popen ( string $command , string $mode )

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

Parameters

command

The command

mode

The mode

Return Values

Returns a file pointer identical to that returned by fopen(), except that it is unidirectional (may only be used for reading or writing) and must be closed with pclose(). This pointer may be used with fgets(), fgetss(), and fwrite(). 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() 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() 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) . "\n";
$read fread($handle2096);
echo 
$read;
pclose($handle);
?>

Notes

Note:

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

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(). Thus, echo y | echo x becomes echo y \| echo x.

See Also

  • pclose() - Closes process file pointer
  • fopen() - Opens file or URL
  • proc_open() - Execute a command and open file pointers for input/output

Коментарии

ive tried using popen using bidirectional pipes without working for obvious reasons, but i managed to create a simple script that managed to take care of the problem.  This example is for gpg encryption.

<?php
   $message 
"this is the text to encrypt with gpg";
   
$sendto 'Dummy Key <another@fake.email>';

   
system("mkfifo pipein");
   
system("mkfifo pipeout");
   
system("gpg --encrypt -a -r '$sendto' > pipeout < pipein &");
   
$fo fopen("pipeout""r");
   
$fi fopen("pipein""w");
   
fwrite($fi$messagestrlen($message));
   
fclose($fi);
   while (!
feof($fo)) {
     
$buf .= fread($fo1024);
   }
   echo 
$buf;
   
unlink("pipein");
   
unlink("pipeout");
?>

If anyone has a better way of doing this I would love to see it.
2002-03-08 18:38:45
http://php5.kiev.ua/manual/ru/function.popen.html
I had all kinds of trouble encrypting a message with PGP, but I finanlly got it to work.  The trick was to 'chmod o+r pubring.pkr' so that the apache server could read the public keys!!!  Then, this function worked fine:

<?PHP
function pgp_encrypt($keyring_location$public_key_id$plain_text) {

       
$key_id EscapeShellArg($public_key_id);
       
putenv("PGPPATH=$keyring_location");

       
// encrypt the message
       
$pipe popen("pgpe -r $key_id -af""r");               
       
fwrite($pipe$plain_text);
       
$encrypted_text '';
        while(
$s fgets($pipe1024)) {
               
// read from the pipe
               
$encrypted_text .= $s;
        }
       
pclose($pipe);

        return 
$encrypted_text;
}

$message pgp_encrypt("/home/username/.pgp""to@domain.com""dummy text to be encrypted");
print 
nl2br($message);

?>
2002-05-24 14:49:10
http://php5.kiev.ua/manual/ru/function.popen.html
The below code works for both way processing ;) Have fun folks

<?php
    system
("mkfifo pipeout");
   
$pipe popen("./nwserver -module Chapter1E > pipeout","w");
   
$pipeout fopen("pipeout""r");
   while (
$s fgets($pipeout,1024)) {
    echo 
$s;
   }

?>
2002-06-30 16:29:52
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
Here is a workaround for not having bidirectional pipes in php.

If you have bidirectional pipe support, don't bother with this.

The trick here is to send the input on the command line to the target application.  In particular I wanted to use openssl without using temp files or named pipes.  This solution should also be thread/process safe.

This does work on Linux (RedHat 7).

<?php
function filterThroughCmd($input$commandLine) {
 
$pipe popen("echo \"$input\"|$commandLine'r');
  if (!
$pipe) {
    print 
"pipe failed.";
    return 
"";
  }
 
$output '';
  while(!
feof($pipe)) {
   
$output .= fread($pipe1024);
  }
 
pclose($pipe);
  return 
$output;
}

# example:
print filterThroughCmd("hello""cat");
# Piping to cat has the effect of echoing your input.
?>
2002-07-12 05:33:24
http://php5.kiev.ua/manual/ru/function.popen.html
I noticed that some of the examples above seem to advocate passing unencrypted data to gpg via the pipe shell escape, in the absence of a bi-directional popen (on some OSes).

The approach I've taken is similar to:

<?php
  $prefix 
'example';
 
$command '/usr/local/bin/gpg --encrypt --armor --no-tty --batch --no-secmem-warning --recipient "joe.soap@example.com"';
 
$tmpfile tempnam('/tmp'$prefix);
 
$pipe popen("$command 2>&1 >$tmpfile"'w');
  if (!
$pipe) {
   
unlink($tmpfile);
  } else {
   
fwrite($pipe$plaintxtstrlen($plaintxt));
   
pclose($pipe);
   
$fd fopen($tmpfile"rb");
   
$output fread($fdfilesize($tmpfile));
   
fclose($fd);
   
unlink($tmpfile);
  }
  return 
$output;
?>

This means that unencrypted information is not passed via a (potentially readable) shell command, and only encrypted information gets stored on disc.
2002-08-08 14:02:34
http://php5.kiev.ua/manual/ru/function.popen.html
From the popen linux programmers manual:

"The  command  argument  is  a pointer to a null-terminated string containing a shell command line.  This  command  is passed  to  /bin/sh  using the -c flag."

Since php uses this popen function, you need to be sure /bin/sh exists. This file may not exist in chroot()ed environments.
2002-11-11 10:58:24
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
Yet another workaround for not having bidirectional pipes in php.

<?php
$Cmd 
=
"bc 2>&1 << END\n" .
"100+221\n" .
"1+3*3\n" .
"quit\n" .
"END\n";

$fp popen($Cmd'r');
$read fread($fp1024);
echo 
$read;
pclose($fp);
?>
2004-03-06 19:53:10
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
I should say, my host uses a modified form of safe mode, so I don't know if that might have caused a problem with "popen" as opposed to "proc_open".  With safe mode enabled, all words following the initial command string are treated as a single argument. Thus, echo y | echo x becomes echo "y | echo x".  [Because of this,] LinixDude010's srcipt did not work for me.  Seems wrong to read and write with popen, according to the manual.

The script produced pgp text, but there was something wrong with the text and I could not decode it.

This replacement script, using proc_open, which can read and write, DOES work:

<?php
function pgp_encrypt($keyring_location$public_key_id$plain_text) {
 
$encrypted_text='';
 
$key_id EscapeShellArg($public_key_id);
 
putenv("PGPPATH=$keyring_location");

 
// encrypt the message
 
$descriptorspec = array(
   
=> array("pipe""r"),  // stdin
   
=> array("pipe""w"),  // stdout
   
=> array("pipe""w")   // stderr ?? instead of a file
 
);
 
$process proc_open("pgpe -r $key_id -af"$descriptorspec$pipes);
  if (
is_resource($process)) {
   
fwrite($pipes[0], $plain_text);
   
fclose($pipes[0]);
    while(
$sfgets($pipes[1], 1024)) {
         
// read from the pipe
         
$encrypted_text .= $s;
    }
   
fclose($pipes[1]);
   
// optional:
   
while($sfgets($pipes[2], 1024)) {
     
$encrypted_text.= "\n<p>Error: $s</p>\n";
    }
   
fclose($pipes[2]);
  }
  return 
$encrypted_text;
}

$message pgp_encrypt("/home/username/.pgp""to@domain.com""dummy text to be encrypted");
print 
nl2br($message);

?>
2005-05-06 15:30:47
http://php5.kiev.ua/manual/ru/function.popen.html
If you want to fork a process under windows, this is the function to use.  I created a batch file called runcmd.bat with the following line

start %1 %2 %3 %4

then I have the folowing function

<?php
define
('RUNCMDPATH''c:\\htdocs\\nonwebspace\\runcmd.bat');

function 
runCmd($cmd) {
   
$externalProcess=popen(RUNCMDPATH.' '.$cmd'r');
   
pclose($externalProcess);
}   
?>

with this, doing something like

<?php runCmd('php.exe printWorkOrder.php 3498'); ?>
will launch php.exe outside of apache and allow the script calling the runCmd() function to continue without waiting for the command line process to return.  The process will run under the same user account that Apache (or whatever webserver you're running) is running under, so make sure it has permissions to do whatever you need to do.  Also, make sure that the batch file has enough %n s in order to pass all the command line variables that you might need to pass.

Special thanks to kicken from the devshed forums for coming up with the idea.
2005-06-20 09:26:15
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
Here is a nice little script for monitoring your http access log.

<?php

$handle 
popen("tail -f /etc/httpd/logs/access.log 2>&1"'r');
while(!
feof($handle)) {
   
$buffer fgets($handle);
    echo 
"$buffer<br/>\n";
   
ob_flush();
   
flush();
}
pclose($handle);

?>

----
www.eviltree.co.uk
www.solidsites.co.uk
www.mongbong.com
2005-09-08 20:39:31
http://php5.kiev.ua/manual/ru/function.popen.html
Truncated output from ps command?

The solution lies in the way ps displays it's info
specifically the -w option which:
'uses 132 columns to display information,
instead of the default which is your window size.'....
somehow with fgets in php that results in 74 characters
regardless off the init length parameter

a bit of code:

<?php
echo '<table width="99%"><tr><td>cron</td></tr>' "\n";
$fp=popen("/bin/ps -waux","r");
while (!
feof($fp)) {
   
$buffer fgets($fp4096);
   
$croninf .= '<tr><td>' $buffer '</td></tr>' "\n";
}
pclose($fp);
echo 
$croninf;
echo 
'</table><br><br>' "\n";
?>

Ciao,

Rene =<>=
2005-11-23 15:16:57
http://php5.kiev.ua/manual/ru/function.popen.html
<?php
// The above import function can be easily extended using 
// /usr/local/bin/xls2csv (part of catdoc ) and popen 
// to read excell files directly. 
// In our particular application the first line was the file heading.
function importxls($file,$head=true,$throwfirst=true,$delim=",",$len=1000) {
   
$return false;
   
$handle popen("/usr/local/bin/xls2csv $file""r");
// or die if not there.
   
if ($throwfirst) {
       
$throw fgetcsv($handle$len$delim);
   }
   if (
$head) {
       
$header fgetcsv($handle$len$delim);
   }
   while ((
$data fgetcsv($handle$len$delim)) !== FALSE) {
       if (
$head AND isset($header)) {
           foreach (
$header as $key=>$heading) {
               
$row[$heading]=(isset($data[$key])) ? $data[$key] : '';
               print 
"<li>"$heading ."=>" $row[$heading]."</li>";
           }
           
$return[]=$row;
       } else {
           
$return[]=$data;
       }
   }
   
fclose($handle);
   return 
$return;
}
?>
2005-12-19 18:28:58
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
Care needs to be taken in the case of long running child processes. Say you want to run tail -f /var/log/messages or in my case burn dvds. If you have a busy wait, Apache2 can sit towards 100%cpu and steadily grow memory. In my case I crashed the server after about an hour and 90% of the dvd burned. During that time apache had consumed a gig of swap.

Offending code - don't copy:

<?php
        $ThisCommand 
sprintf("%s %s",COMMAND,$ThisFile);
       
$fp=popen($ThisCommand,"r");
        while (!
feof($fp)) {
               
set_time_limit (20);
               
$results fgets($fp4096);
                if (
strlen($results) == 0) {
                   
// stop the browser timing out
                   
echo " ";
                   
flush();
                } else {
                   
$tok strtok($results"\n");
                   while (
$tok !== false) {
                        echo 
htmlentities(sprintf("%s\n",$tok))."<br/>";
                       
flush();
                       
$tok strtok("\n");
                   }
                }
        }
       
pclose($fp);
?>

to go from zero memory and 100% cpu  to negligible memory and negligible cpu add a sleep.

<?php
       
while (!feof($fp)) {
               
set_time_limit (20);
               
$results fgets($fp256);
                if (
strlen($results) == 0) {
                   
// stop the browser timing out
                   
echo " ";
                   
flush();
                } else {
                   
$tok strtok($results"\n");
                   while (
$tok !== false) {
                        echo 
htmlentities(sprintf("%s\n",$tok))."<br/>";
                       
flush();
                       
$tok strtok("\n");
                   }
                }
               
// avoid a busy wait
               
sleep(1);

        }
?>

I think the continued banging of the space to keep the browser awake triggered some issues in apache.
2007-04-14 00:42:40
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
Note, when using this with a batch file in windows, you must put an "exit" at the end of your batch file or you will get a new cmd.exe stuck in your process list every time you execute the page.
2007-09-10 14:25:06
http://php5.kiev.ua/manual/ru/function.popen.html
If you want to download files from a linux server with a filesize bigger than 2GB you can use the following:

<?php
function serveFile$file $as ){
   
header'Expires: Mon, 1 Apr 1974 05:00:00 GMT' );
   
header'Pragma: no-cache' );
   
header'Cache-Control: must-revalidate, post-check=0, pre-check=0' );
   
header'Content-Description: File Download' );
   
header'Content-Type: application/octet-stream' );
   
header'Content-Length: '.trim(`stat -c%s "$file"`) );
   
header'Content-Disposition: attachment; filename="'$as .'"' );
   
header'Content-Transfer-Encoding: binary' );
   
//@readfile( $file );

   
flush();
   
$fp popen("tail -c ".trim(`stat -c%s "$file"`)." ".$file.' 2>&1'"r");
    while(!
feof($fp))
    {
       
// send the current file part to the browser
       
print fread($fp1024);
       
// flush the content to the browser
       
flush();
    }
   
fclose($fp);
}
?>
2009-02-03 05:43:20
http://php5.kiev.ua/manual/ru/function.popen.html
If you try to execute a command under Windows the PHP script normally waits until the process has been terminated. Executing long-term processes pauses a PHP script even if you don't want to wait for the end of the process.

It wasn't easy to find this beautiful example how to start a process under Windows without waiting for its termination:

<?php
$commandString 
'start /b c:\\programToRun.exe -attachment "c:\\temp\file1.txt"';
pclose(popen($commandString'r'));
?>
2009-07-23 09:36:25
http://php5.kiev.ua/manual/ru/function.popen.html
Note that you *have* to do a read on the handle before you can feof(), even if the command outputs nothing! So..

<?php
$f
=popen("sleep 2","r");
while (!
feof($f)) {}
pclose($f);
print 
"done";
?>

will never finish.
2010-01-20 20:26:56
http://php5.kiev.ua/manual/ru/function.popen.html
There is a simple way to start a process in the background but still find out what the process result is. I combined the information from some users below with some of my own coming up with the following:

<?php
$bat_filename 
"C:\\my_bat_file.bat";
$bat_log_filename "C:\\my_bat_file_bat.log";
$bat_file fopen($bat_filename"w");
if(
$bat_file) {
   
fwrite($bat_file"@echo off"."\n");
   
fwrite($bat_file"echo Starting proces >> ".$bat_log_filename."\n");
   
fwrite($bat_file"php c:\\my_php_process.php >> ".$bat_log_filename."\n");
   
fwrite($bat_file"echo End proces >> ".$bat_log_filename."\n");
   
fwrite($bat_file"EXIT"."\n");
   
fclose($bat_file);
}
           
//
// Start the process in the background
//
$exe "start /b ".$bat_filename;
if( 
pclose(popen($exe'r')) ) {
    return 
true;
}
return 
false;
?>

In my case the file names of the .bat and .log files weren't always the same, so I needed a dynamic way to create the .bat file. The output from the php command is saved to the log file with the >> command. All prints and errors are stored there. At a later time you can open the log file and see what happened.
2010-04-19 12:03:58
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
If you are running in a chroot'ed environment on Debian "Squeeze", this command won't work; there is a problem with the kernel code that popen() eventually calls.

Note that pecl makes heavy use of this command, so if you are running in this environment you will need to install the pecl extension from source instead.
2010-09-06 19:08:45
http://php5.kiev.ua/manual/ru/function.popen.html
If, on windows, you need to start a batch file that needs administrator privileges, then you can make a shortcut to the batch file, click properties, check to on "run as administrator" on one of the property pages, and then double-click the shortcut once (to initialize that "run as administrator" business).

using popen("/path/to/shortcut.lnk") will then run your batch file with administrator privileges.

handy for when you want to use cli php to do some long running tasks and that php-cli needs to use sessions..
2011-02-08 03:39:58
http://php5.kiev.ua/manual/ru/function.popen.html
As a side note to the code provided by anonymous at anon dot com:

  $cmd = "php longscript.php";

  function execInBackground($cmd) { 
    if (substr(php_uname(), 0, 7) == "Windows"){
        pclose(popen("start /B ". $cmd, "r")); 
    } else { 
        exec($cmd . " > /dev/null &");   
    } 
  } 

I had a problem where Windows would close the call too fast before the entire script was interpreted, but I didn't want my main script to hang until it would be fully loaded.

As a workaround, I called a tiny .php script which would then call the larger script.

myfile.php:
<?php
  $cmd 
"php timewrapper.php";

  function 
execInBackground($cmd) { 
    if (
substr(php_uname(), 07) == "Windows"){
       
pclose(popen("start /B "$cmd"r")); 
    } else { 
       
exec($cmd " > /dev/null &");   
    } 
  } 
?>

timewrapper.php:
<?php
  $cmd 
"php longscript.php";
 
$timer popen("start /B "$cmd"r"); 
 
sleep(30);
 
pclose($timer);
?>

This way my main script would continue to run without having to pause, while the tiny script pauses while it loads the larger file.
2015-03-26 00:28:24
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
Don't expect this function to return false when the executable doesn't exist in the first place. A stream will be opened anyway but nothing can be read from it. An error similar to "sh: 1: asdfasdfasdf: not found" will be printed to STDERR.

Solution 1: Look at the return value of pclose(), it will be the exit status of the shell that runs the command. On Linux it will be 127 if the executable wasn't found. Otherwise it's the exit status of the executable itself.

Solution 2: Use proc_open() instead, which allows to also capture STDERR and then parse it for errors.

You probably should do both.
2016-08-10 10:20:57
http://php5.kiev.ua/manual/ru/function.popen.html
Another workaround for using popen() with "w" mode so that the stdout of the command reaches the browser:

An easy solution is to have two php scripts; "real.php" with the popen($cmd, "w") command in it, the other being "wrapper.php", a one liner that simply invokes system("php real.php");

Invoking "wrapper.php" from the browser allows the popen($cmd,"w") in "real.php" to work as expected, such that stdout of $cmd reaches the browser. If you try to skip the wrapper and just run "real.php", stdout of $cmd is lost to /dev/null.
2018-10-01 13:21:10
http://php5.kiev.ua/manual/ru/function.popen.html
Автор:
Note for Windows users using popen with start to run an external script without having php wait.

e.g.:
pclose( popen(  'start /b php someLongScript.php *> nul', 'rb' ) );

If start can't find the exe it will open a popup message and pclose hangs until the popup is closed.
2021-09-17 12:20:02
http://php5.kiev.ua/manual/ru/function.popen.html

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