I had a problem earlier in the week where I needed to merge multiple PDF files together so they could be printed in one long run. I thought it was going to be one of those tasks that caused me to have a serious headache, but to my surprise it was rather easy.

Lets say you have 5 PDF files named “doc_1.pdf, doc_2.pdf, doc_3.pdf, doc_4.pdf and doc_5.pdf” and you need them to be merged into one file called “docs_joined.pdf”. All you have to do is use the following function:

shell_exec();

This function executes a command via shell and in this case the Linux command you want to call is ‘gs’, which is Ghostscript, a PostScript and PDF language interpreter and previewer.

So using both shell_exec() and ‘gs’ we would do the following to join the PDFs together:

$output = shell_exec(‘gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=docs_joined.pdf doc_1.pdf doc_2.pdf doc_3.pdf doc_4.pdf doc_5.pdf);

And you’re done. Simple!