Detect pdf landscpe with ssh pdfinfo

After researching to see how I can make PHP know the orientation of the pdf, and found a solution with pdfinfo, it works fine by bash. but I can’t get that by PHP with executing exec command, I receive the response under the string to be able to create an if rule. I do not understand why the if of the PHP does not work with the answer of the ssh.

    $test = shell_exec(' pdfinfo 
    -f 1 
    -l 1 
     sample.pdf 
| grep "Page.* size:" 
| 
 while read Page _pageno size _width x _height rest; do 
  [ "$(echo "${_width} / 1"|bc)" -gt "$(echo "${_height} / 1"|bc)" ] 
     && echo "landscape" 
    || echo "portrait"  ; 
 done');

if($test=="portrait"){
    echo "run script from portrait";
}else{
    echo"run script from landscape";
}

Answer

There could be white space in the returned value. Use trim($test) before the if condition to trim the white space.