gs file.pdf # show pdf file

pdftk 1.pdf 2.pdf 3.pdf cat output out.pdf   # preserves bookmarks

gs -sDEVICE=pdfwrite -dColorConversionStrategy=/LeaveColorUnchanged -dDownsampleMonoImages=false -dDownsampleGrayImages=false -dDownsampleColorImages=false -dAutoFilterColorImages=false -dAutoFilterGrayImages=false -dColorImageFilter=/FlateEncode -dGrayImageFilter=/FlateEncode -o out.pdf in.pdf

gs -sDEVICE=pdfwrite -o merged.pdf in1.pdf in2.pdf   # does not preserve bookmarks

gs -sDEVICE=pdfwrite -dNoOutputFonts -o out.pdf in.pdf    # text to path

rsvg-convert -f pdf -o file.pdf file.svg

cpdf -twoup in.pdf -o out.pdf   # merges 2 pages into one

qpdf --pages . 2-z -- in.pdf out.pdf    # remove page 1

qpdf --pages in.pdf 2-z -- --empty out.pdf    # remove page 1 and discards metadata

pdftk a.pdf dump_data > info.txt pdftk out.pdf update_info info.txt output final.pdf

pdftk A=a.pdf B=b.pdf cat A1-[N] B A[N+1]-end output out.pdf

eval `/Applications/DjView.app/Contents/setpath.sh` djvused -e print-outline book.djvu > toc.txt djvused -e 'set-outline toc.txt' book.djvu

scantailor

pdfimages -j -jp2 in.pdf out

for x in *.jpg; do c44 -dpi 300 $x; done; djvm -c out.djvu *.djvu    # convert & merge greyscale images to djvu