Question

I’m working on a simple PHP based website

The basic structure is :

• It takes some data as input via a web form, hands it over to some
  shell scripts to process (via the system() function)

• The result of the processing is written to a .txt file

• This file is then read by the script and displayed in the browser

It takes about 2-3 seconds to generate the .txt file after the handover is completed

Is there any correct way of making PHP wait for the file to be generated?

Currently I put the PHP script to sleep for 5 seconds and then read the file exists. This is obviously not a very good idea since each time the PHP script executes, it will take 5 seconds regardless of the time actually needed.

Runs on Apache on Ubuntu if thats relevant

Answer 1

Simple answer: Don’t use system(), use exec() without redirecting to a file:

$foo = array();
exec('ls', $foo);
$output = implode("\n", $foo);