PHP 7.0.6 Released

    passthru

    (PHP 4, PHP 5, PHP 7)

    passthru — Execute an external program and display raw output

    Description

    void passthru ( string $command [, int &$return_var ] )

    The passthru() function is similar to the exec() function in that it executes a command. This function should be used in place of exec() or system() when the output from the Unix command is binary data which needs to be passed directly back to the browser. A common use for this is to execute something like the pbmplus utilities that can output an image stream directly. By setting the Content-type to image/gif and then calling a pbmplus program to output a gif, you can create PHP scripts that output images directly.

    Parameters

    command

    The command that will be executed.

    return_var

    If the return_var argument is present, the return status of the Unix command will be placed here.

    Return Values

    No value is returned.

    Notes

    Warning

    When allowing user-supplied data to be passed to this function, use escapeshellarg() or escapeshellcmd() to ensure that users cannot trick the system into executing arbitrary commands.

    Note:

    If a program is started with this function, in order for it to continue running in the background, the output of the program must be redirected to a file or another output stream. Failing to do so will cause PHP to hang until the execution of the program ends.

    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

    User Contributed Notes

    igor at bboy dot ru
    10 years ago
    If you are using passthru() to download files (for dynamically generated content or something outside webserver root) using similar code:

    header("Content-Type: application/octet-stream");
    header("Content-Disposition: attachment; filename=\"myfile.zip\"");
    header("Content-Length: 11111");
    passthru("cat myfile.zip",$err);

    and your download goes fine, but subsequent downloads / link clicks are screwed up, with headers and binary data being all over the website, try putting

    exit();

    after the passthrough. This will exit the script after the download is done and will not interfere with any future actions.
    myselfasunder at gmail dot com dot dfvuks
    5 years ago
    PHP's program-execution commands fail miserably when it comes to STDERR, and the proc_open() command doesn't work all that consistently in non-blocking mode under Windows.

    This command, although useful, is no different. To form a mechanism that will see/capture both STDOUT and STDERR output, pipe the command to the 'tee' command (which can be found for Windows), and wrap the whole thing in output buffering.

    Dustin Oprea
    Zak Estrada
    11 years ago
    Remember to use the full path (IE '/usr/local/bin/foo' instead of 'foo') when using passthru, otherwise you'll get an exit code of 127 (command not found).
    sarel dot w at envent dot co dot za
    11 years ago
    Zak Estrada
    14-Dec-2004 11:21
    Remember to use the full path (IE '/usr/local/bin/foo' instead of 'foo') when using passthru, otherwise you'll get an exit code of 127 (command not found).

    Remember, you'll also get this error if your file does not have executable permission.
    Chroot
    7 years ago
    If you have chrooted apache and php, you will also want to put /bin/sh into the chrooted environment. Otherwise, the exec() or passthru() will not function properly, and will produce error code 127, file not found.
    PJ at piggei dot com
    15 years ago
    About the problem of zombies, you may call a bash script like this:

    --------------------------
    #! /bin/bash
    ulimit -t 60

    <your command here>
    --------------------------
    nuker at list dot ru
    10 years ago
    I wrote function, that gets proxy server value from the Internet Explorer (from
    registry). It was tested in Windows XP Pro

    (Sorry for my English)

    <?php
    function getProxyFromIE()
    {
                exec("reg query \"HKEY_CURRENT_USER\Software\Microsoft".
                "\Windows\CurrentVersion\Internet Settings\" /v ProxyEnable",
                $proxyenable,$proxyenable_status);

                exec("reg query \"HKEY_CURRENT_USER\Software\Microsoft".
                "\Windows\CurrentVersion\Internet Settings\" /v ProxyServer",
                $proxyserver);

            if(    $proxyenable_status!=0)
            return     false; #Can't access the registry! Very very bad...
                else
            {
                $enabled=substr($proxyenable[4],-1,1);
            if(    $enabled==0)
            return     false;
            else
            {
                $proxy=ereg_replace("^[ \t]{1,10}ProxyServer\tREG_SZ[ \t]{1,20}","",
                $proxyserver[4]);

            if(    ereg("[\=\;]",$proxy))
            {
                     $proxy=explode(";",$proxy);
                 foreach(    $proxy as $i => $v)
                 {
                       if(    ereg("http",$v))
                       {
                           $proxy=str_replace("http=","",$v);
                       break;
                       }
                 }
                 if(@!    ereg("^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\:".
                     "[0-9]{1,5}$",$proxy))
                 return     false;
                 else
                 return     $proxy;
            }
            else
            return     $proxy;
            }

            }
    }
    ?>
    Note, that this function returns FALSE if proxy is disabled in Internet
    Explorer. This function returns ONLY HTTP proxy server.

    Usage:
    <?php
    $proxy    =getProxyFromIE();
    if(!    $proxy)
    echo     "Can't get proxy!";
    else
    echo     $proxy;
    ?>
    jo at durchholz dot org
    8 years ago
    Note to Paul Giblock: the command *is* run through the shell.
    You can verify this on any Linux system with

    <?php
    passthru     ('echo $PATH');
    ?>

    You'll get the content of the PATH environment variable, not the string $PATH.
    swbrown at ucsd dot edu
    12 years ago
    passthru() seems absolutely determined to buffer output no matter what you do, even with ob_implicit_flush().  The solution seems to be to use popen() instead.
    Paul Giblock
    8 years ago
    Stuart:

    The pasthru function does not execute the program through the shell.  What this mean, among other things, is that your PATH variable is never set.  Therefore, you have to use full paths on everything.

    I believe system() will run your program underneith a shell.  This allow the program to run in a 'normal' environment.

    -Paul
    stuartc1 at NOSPAM dot hotmail dot com
    10 years ago
    Thought it might beuseful to note the passthru seems to supress error messages whilst being run in Dos on Windows (test on NT).

    To show FULL raw output including errors, use system().
    puppy at cyberpuppy dot org
    11 years ago
    Regarding swbrown's comment...you need to use an output buffer if you don't want the data displayed.

    For example:
    ob_start();
    passthru("<i>command</i>");
    $var = ob_get_contents();
    ob_end_clean(); //Use this instead of ob_flush()

    This gets all the output from the command, and exits without sending any data to stdout.
    kpierre at fit dot edu
    14 years ago
    The documention does not mention that passthru() will only display standard output and not standard error.

    If you are running a script you can pipe the STDERR to STDOUT by doing

    exec 2>&1

    Eg. the script below will actually print something with the passthru() function...

    #!/bin/sh
    exec 2>&1
    ulimit -t 60
    cat nosuchfile.txt
    sidney at jigsaw dot nl
    14 years ago
    PJ's ulimit example is nice; however, if you include multiple commands in the script after the ulimit command, each gets its own, seperate 60 second time slot!<br>

    Furthermore, these sixty seconds are *CPU* time. Most programs hang for other reasons than CPU hogging (for example, waiting for a database connection) so for most purposes the number 60 is rather too high.<br>

    Try "ulimit -t 1" first, which will give you about 10^9 cycles on modern hardware -- quite enough to get a lot of work done!
    vijayramanan at rediffmail dot com
    10 years ago
    I had an issue when i used exec

    I think we were echoing information on the test.php script.
    for eg: when we tried

    exec(php test.php,$array,$error);

    the return was 127 and the code was failing.

    checking the note on this page gave us a hint to use passthru instead.
    The only thing to note is that you need to provide the fuull path.

    now our command became

    passthru(/bin/php /pathtotest/test.php,$array,$error);

    this works.

    yipeee!!!!!
    andreas dot hochsteger at oeamtc dot at
    14 years ago
    If you sometimes get no output from passthru() use system() instead. This solved this problem for me (php 4.0.5 on Tru64 Unix compiled with gcc).
    Stuart Eve
    10 years ago
    I dunno if anyone else might find this useful, but when I was trying to use the passthru() command on Suse9.3 I was having no success with the command:

    $command = 'gdal_translate blahahahaha';

    passthru($command);

    It only worked once I put:

    $command = '/usr/bin/local/gdal_translate blalalala';

    passthru($command);
    php @ richud dot com
    11 years ago
    Regarding kpierre's post, be mindful that if you shell script errors, you will find the error output from it in the base error_log file (not virtualhost error_log) in apache.
    jcr at marvel-databadge dot com
    12 years ago
    With apache 2.x on RH9 passthru() writes 1 byte at a time. Apache 2.x buffers and chunk encodes the output for you - but the chunked encoding devides the output in chunks of 1 byte each...thus several bytes of overhead per byte. I guess that buffering behaviour is by design - but caused problems for me with IE adobe acrobot 5 plugin. The plugin doesn't like like it if you send it a stream of 1 byte chunks - it tells you your file is not a pdf or gives a blank screen. Using output buffering (ob_start / ob_endflush) gives reasonable size chunks and the plugin works OK.
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