Merge PDF files with PHP

i suggest PDFMerger from github.com, so easy like ::

include 'PDFMerger.php';

$pdf = new PDFMerger;

$pdf->addPDF('samplepdfs/one.pdf', '1, 3, 4')
    ->addPDF('samplepdfs/two.pdf', '1-2')
    ->addPDF('samplepdfs/three.pdf', 'all')
    ->merge('file', 'samplepdfs/TEST2.pdf'); // REPLACE 'file' WITH 'browser', 'download', 'string', or 'file' for output options

Below is the php PDF merge command.

$fileArray= array("name1.pdf","name2.pdf","name3.pdf","name4.pdf");

$datadir = "save_path/";
$outputName = $datadir."merged.pdf";

$cmd = "gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=$outputName ";
//Add each pdf file to the end of the command
foreach($fileArray as $file) {
    $cmd .= $file." ";
}
$result = shell_exec($cmd);

I forgot the link from where I found it, but it works fine.

Note: You should have gs (on linux and probably Mac), or Ghostscript (on windows) installed for this to work.