PHP shell_exec() not working for some commands like wc

Question

I have ubuntu 12.04 with PHP 5.3,Apache2 installed. I needed to count the words in a doc file using php and pdf. while i am able to do shell_exec for text to pdf but not for wc. here is the code

    <?php
    $content = shell_exec('pdftotext test.pdf -');
    echo str_word_count($content);// this is working

    $word_count = exec('wc -w test.doc'); //this is not working
    echo $word_count;
    ?>

However the code works in command line.

Answer 1

Actually there was a problem with my ubuntu Release 12.04. I tried it with ubuntu 11.10 and with LAMP. And everything worked like a charm. I will reinstall this dist of ubuntu and check again.

Answer 2

<?php

   echo exec('wc -w test.doc;echo $?'); 

?>

try this to see what you can get. if the result is 0,it works,otherwise some error informations will be given.