Error while executing exec('php -v') in php returning garbage (HTTP Response)

I've a shared server Linux based on which I am facing a weird problem. I am trying to execute by PHP, the following command and it runs ok; returning me the PHP install path /usr/bin/php.

exec('which php');// This runs so exec is not disabled

but any command i try to execute with exec('php ...'); fails returning me an array of 98 to 114 elements randomly which almost has garbage all over. Examples of commands i ran are...

exec('php -v');
exec('php -i');
exec('/usr/bin/php -v');

None of the above returned something sensible. Any idea why any command ran by php is not executing?

Below is the var_dump() of the data array that exec() is returning to me.

EDIT (After some more RND)

I was able to execute

exec('php -h')

and it reuturned me the following array in readable format.

string(9) "php -help"
string(47) "Usage: php [-q] [-h] [-s] [-v] [-i] [-f ]"
string(27) "       php  [args...]"
string(36) "  -a               Run interactively"
string(69) "  -b | Bind Path for external FASTCGI Server mode"
string(57) "  -C               Do not chdir to the script's directory"
string(58) "  -c | Look for php.ini file in this directory"
string(47) "  -n               No php.ini file will be used"
string(56) "  -d foo[=bar]     Define INI entry foo with value 'bar'"
string(70) "  -e               Generate extended information for debugger/profiler"
string(46) "  -f         Parse .  Implies `-q'"
string(28) "  -h               This help"
string(34) "  -i               PHP information"
string(43) "  -l               Syntax check only (lint)"
string(43) "  -m               Show compiled in modules"
string(60) "  -q               Quiet-mode.  Suppress HTTP Header output."
string(60) "  -s               Display colour syntax highlighted source."
string(33) "  -v               Version number"
string(72) "  -w               Display source with stripped comments and whitespace."
string(46) "  -z         Load Zend extension ."
string(75) "  -T        Measure execution time of script repeated  times."
This page was created in 0.055487155914307 seconds

Oh btw the script i am using to test is the following...

<?php
$mtime = microtime(); 
$mtime = explode(" ",$mtime); 
$mtime = $mtime[1] + $mtime[0]; 
$starttime = $mtime; 


if(!empty($_GET['p']) && $_GET['p'] == true){

    //$command = 'php -help'; //this works
    //$command = 'cat ' . getcwd() . '/dummy1.txt'; //this works echo's a simple text file

    //$command = 'php -q ' . getcwd() . '/dummy1.txt'; //NOT WORKING
    $command = 'php -m'; //NOT WORKING

    echo '<div><pre>';
    var_dump($command);
    echo '</pre></div>';

    exec($command, $output, $return);
    //passthru($command,$output);

    echo '<div><pre>';
    foreach($output as $key => $value){
        var_dump($output[$key]);
    }   
    echo '</pre></div>';
}


$mtime = microtime(); 
$mtime = explode(" ",$mtime); 
$mtime = $mtime[1] + $mtime[0]; 
$endtime = $mtime; 
$totaltime = ($endtime - $starttime); 
echo "This page was created in ".$totaltime." seconds";
?>

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