Bash output - is it possible to get "realtime" output?

[ubuntu-user]

Hello

 

I have a PHP web application that needs to run a bash script that takes around 15 seconds to run. What I need is for the bash script output - which outputs progress - to be displayed in my PHP web application in "realtime". i.e. each time bash outputs something, it is displayed in the users browser.

 

For the purpose of this thread, let's choose a bash example as follows:

 

COUNTER=1
while [ $COUNTER -le 10 ]; do
        echo "Counter: $COUNTER"
        COUNTER=$((COUNTER+1))
        sleep 1
done

 

As you can see, it will echo a counter number from 1 to 10, pausing for 1 second in between.

 

Now I can get this to display in my PHP application, but not in the same way it displays when running it directly in BASH.

 

echo "<pre>";
$cmd = "sh /usr/local/bin/test"; 
system($cmd);
echo "</pre>";

 

What typically happens is that output comes out as follows:

 

Counter: 1

Counter: 2

 

then

 

Counter: 3

Counter: 4

Counter: 5

Counter: 6

 

then

 

Counter: 7

Counter: 8

Counter: 9

Counter: 10

 

i.e. it is sporadic and not like the BASH output.

 

I've tried various PHP functions like exec, shell_exec and passthru.

 

Is this actually possible? I've seen it before in web applications when running BASH scripts, but they might have been Perl based.

 

This application is for internal use, so I have full access as admin to the server it's on.

 

I'm using:

Ubuntu 9.10

PHP 5.2.10

LightTPD for my server

 

Thanks

[Daniel0]

Try something like this:

 

<?php
$handle = popen('sh /usr/local/bin/test', 'r');
while (!feof($handle)) {
        echo fgets($handle);
        flush();
        ob_flush();
}
pclose($handle);

 

Your webserver might still buffer output though. In that case there is nothing you can do from the PHP side.