Juntar ficheros PDF

Para juntar varios ficheros pdf podemos usar Ghostscript:

gs -sDEVICE=pdfwrite \
    -dNOPAUSE -dBATCH -dSAFER \
    -sOutputFile=combined.pdf \
    first.pdf \
    second.pdf \
    third.pdf [...]

Info obtenida de: http://www.linuxjournal.com/content/tech-tip-using-ghostscript-convert-and-combine-files