php exec() function for pdf to html and pdf to text file conversion

php exec() function for pdf to html and pdf to text file conversion :

$sourcePath = "formula.pdf";
$destinationPath = "/pdf/formula.html";
$destinationPath1 = "/pdf/formula.txt";

// For convert pdf to html
exec("/usr/bin/pdftohtml $sourcePath $destinationPath");

// For convert pdf to text
exec("/usr/bin/pdftohtml $sourcePath $destinationPath1");

?>

Available other conversions :
pdf2dsc
pdf2ps
pdffonts
pdfimages
pdfinfo
pdfopt
pdftoppm
pdftops