如何从浏览器在命令行中执行外部PHP脚本

Question

I have an external php script named external.php which includes this:

<?php
echo 'External Output';
?>

When I run that on command line with command:

php external.php

I get output as

External Output

But when the same script I execute from my browser's php file named index.php which has this code:

<?php
$exe=exec('php external.php',$out,$ret);
print_r($out);
?>

Then I get no output.

When I modify it as:

<?php
$exe=exec('php external.php 2>&1',$out,$ret);
print_r($out);
?>

Then I get this output:

php: /opt/lampp/lib/libxml2.so.2: version `LIBXML2_2.9.0' not found (required by php)

My question is, how can I execute that "external.php" file in commandline from index.php and get output on my browser (i.e. on index.php) ? I have tried system() function too, it doesn't work as well.

Edit: I cannot include the external.php in index.php because external.php can take lot of time to execute (more than 10 hours).

Edit#2 Solved it, giving the full path to PHP solved the problem.

Here is an example:

<?php
$exe=exec('full/path/to/php /full/path/to/external.php',$out,$ret);
print_r($out);
?>

Thankyou Oleg and Scopey for giving me some hint help.

Answer 1

Specify the full path of external.php:

<?php
$exe=exec('php /full/path/to/external.php',$out,$ret);
print_r($out);
?>

Try also specifying the full path to php on the command line and check that it works:

$/usr/bin/php "/full/path/to/external.php"

If that works, try it also in your php file:

<?php
$exe=exec('/usr/bin/php /full/path/to/external.php',$out,$ret);
print_r($out);
?>