Bash script live output executed from PHP - php

Question

I'm trying to execute a bash script from php and getting its output in real time.
I am applying the answers found here:
However they are not working for me.
When I invoke the .sh script on this way, it works fine:
<?php
$output = shell_exec("./test.sh");
echo "<pre>$output</pre>";
?>
However, when doing:
<?php
echo '<pre>';
passthru(./test.sh);
echo '</pre>';
?>
or:
<?php
while (# ob_end_flush()); // end all output buffers if any
$proc = popen(./test.sh, 'r');
echo '<pre>';
while (!feof($proc))
{
echo fread($proc, 4096);
# flush();
}
echo '</pre>';
?>
I have no output in my browser.
I also tried to call the variable instead of the script in both cases, I mean:
<?php
$output = shell_exec("./test.sh");
echo '<pre>';
passthru($output);
echo '</pre>';
?>
This is my test.sh script:
#!/bin/bash
whoami
sleep 3
dmesg

Answer 1

Use the following:
<?php
ob_implicit_flush(true);
ob_end_flush();
$cmd = "bash /path/to/test.sh";
$descriptorspec = array(
0 => array("pipe", "r"), // stdin is a pipe that the child will read from
1 => array("pipe", "w"), // stdout is a pipe that the child will write to
2 => array("pipe", "w") // stderr is a pipe that the child will write to
);
$process = proc_open($cmd, $descriptorspec, $pipes, realpath('./'), array());
if (is_resource($process)) {
while ($s = fgets($pipes[1])) {
print $s;
}
}
?>
Change test.sh to:
#!/bin/bash
whoami
sleep 3
ls /
Explanation:
dmesg requires permissions. You need to grant webserver's user permissions for that. In my case apache2 is being run via www-data user.
ob_implicit_flush(true): Turns implicit flushing on. Implicit flushing will result in a flush operation after every output call, so that explicit calls to flush() will no longer be needed.
ob_end_flush(): Turns off output buffering, so we see results immediately.