Combine Multiple PDFs with Ghostscript

I've often found myself wanting to combine PDF documents, and always have to resort to google to figure out how to do it without installing some unnecessarily large software.  The following Ghostscript, which is very likely already installed on your system, will do the trick:

gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=merged.pdf part1.pdf part2.pdf

Credit to Roel Van de Paar's SO answer from here.