Recently, I needed to combine several pdf files into one. The The Tao of Mac has a discussion of how to do this and I’m posting the code I used here so that I can find it again later.

gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf -c save pop -f *.pdf

Running this from a directory containing only the pdfs to be combined produces out.pdf.