Progress bar for a bash script running from php

Question

With unvaluable help from people on StackOverflow I managed to run a bash script from php. Now everything is running fine but as the script takes some minutes to end I would like to see progress. In the bash script there are some printf commands that output error/success messages.

As a newbie in php I assumed those messages would appear as they are executed in the bash script. But I don't get any output although the script is finished. I can see the files created and for sure the script finished but I can't see any output from php in the browser.

How can I check the progress when the script is still running? Why php does not seem to end?

Following is the php script.

<?php

echo "<!DOCTYPE html PUBLIC -//W3C//DTD XHTML 1.0 Strict//EN http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd>
      <html xmlns=http://www.w3.org/1999/xhtml>
      <head>
      <meta http-equiv=Content-Type content=text/html; charset=UTF-8 />
      <title>Title</title>
      <link href=../style.css rel=stylesheet type=text/css>
      </head>
      <body topmargin=0 leftmargin=0>";
echo '<font color=blue>';

echo '------------------------------------------------------------- <br>';
echo 'Inicio de la generación manual de mapas de olas de calor<br>';
echo 'Este proceso tarda varios minutos<br>';
echo '-------------------------------------------------------------<br>';
echo date('h:i:s') . "\n";
$output = shell_exec('/home/meteo/www/RAMS/olas/generar-mapas.bash');
echo "<pre>".$output."</pre>";
echo '</font>';
echo '</body>';
echo '</html>';

?>

I've read some posts in the forum about php, Ajax and jQuery for progress bars but I just know some very basic php. Is there a simple solution for a novice in php? Thanks for your help

Pro PHP Tip: don't feel the need to echo absolutely everything. You can simply close the ?>, output HTML, then reopen the <?php when you need to. Pro HTML Tip: the <font> tag is very old-fashioned and should no longer be used. If you want the font to be blue, use CSS. — Tom Fenech
– Tom Fenech, Commented Feb 18, 2015 at 11:59
@tom-fenech Agree with the use of CSS, just a copy-paste mistake. Don't need to echo everything but the point is that any single echo appears. Sorry if too basic but what does close ?> means? Is it not closed? the html output does not appear. Thanks for answering. — pacomet
– pacomet, Commented Feb 18, 2015 at 12:12
I thought of a solution by sending the output of the bash script to an autorefreshing html open in an iframe. But it seems a tricky workaround, there should be a nice clean php way to do it. — pacomet
– pacomet, Commented Feb 18, 2015 at 12:15
This is general advice, separate to your issue, which is why I only posted it as a comment. You can open and close PHP tags in the middle of your script, so you don't need to write all of your HTML in a PHP string. Hope that makes sense. — Tom Fenech
– Tom Fenech, Commented Feb 18, 2015 at 12:16

Marek · Accepted Answer · 2015-02-18 14:04:46Z

1

shell_exec() blocks till the child process finishes, use popen() instead:

$p = popen('/home/meteo/www/RAMS/olas/generar-mapas.bash', 'r');
while(!feof($p)) {
    echo fgets($p);
    ob_flush();
    flush();
}
pclose($p);

edited Feb 18, 2015 at 14:04

answered Feb 18, 2015 at 13:24

Marek

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3 Comments

pacomet Over a year ago

Hi @marek and thanks. It seems popen does not work for me. It does not start any process, bash script does not run.

Marek Over a year ago

I forgot to add mode, I hope that helps. It might be neccessary to output more bytes, in case there's implicit buffer somewhere.

pacomet Over a year ago

Just needed to add 2>&1','r' to popen on your answer

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