Run shell script from php and see complete progress? - php

Question

Is there a way to run a shell script from PHP and echo the results after progress is completed?
Here is my shell script:
(Its multilines - a few commands that have to be ran one after the other. )
cd
cd /var/www/html/
npm uninstall gulp --save
npm install gulp --save
npm start
here's my currently functioning PHP script. It only outputs some of the progress and only outputs it when complete. I need a live preview of the progress.
<?php
echo "loaded<br><br>";
// echo shell_exec("cd /var/www/html/..");
// rin the shell scrip from header_register_callback
echo '<pre>';
// Outputs all the result of shellcommand "ls", and returns
// the last output line into $last_line. Stores the return value
// of the shell command in $retval.
$last_line = system('cd /var/www/html/; npm start', $retval);
// Printing additional info
echo '
</pre>
<hr />Last line of the output: ' . $last_line . '
<hr />Return value: ' . $retval;
?>

Answer 1

Here is another approach. It uses redirection to output the results and then file_get_contents() to read the output.
<?php
echo "loaded<br><br>";
$cmd = 'npm start';
$run = $cmd . ' > result.txt 2> errors.txt';
$output = shell_exec($run);
$results = file_get_contents('result.txt');
if (strlen(file_get_contents('errors.txt')) != 0) {
$results .= file_get_contents('errors.txt');
}
echo "<pre>$results</pre>";
?>

Answer 2

I guess, ob_flush() would work:
<?php
echo "loaded<br><br>";
ob_flush();
// echo shell_exec("cd /var/www/html/..");
// rin the shell scrip from header_register_callback
echo '<pre>';
ob_flush();
// Outputs all the result of shellcommand "ls", and returns
// the last output line into $last_line. Stores the return value
// of the shell command in $retval.
$last_line = system('cd /var/www/html/; npm start', $retval);
// Printing additional info
echo '
</pre>
<hr />Last line of the output: ' . $last_line . '
<hr />Return value: ' . $retval;
?>
But I don't understand why you echo HTML-tags when you run that script on the console... Hope I got you right