Ghostscript

• Merge PDFs
• Split PDF
  • Using ‘convert’
• Reduce file size/quality

Some ghostscript snippets

Merge PDFs

gs -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE="merged_file.pdf" \
   -dBATCH file1.pdf file2.pdf file3.pdf ... fileN.pdf

Split PDF

yes | gs -dBATCH -sOutputFile="output.pdf" -dFirstPage=100 \
  -dLastPage=105 -sDEVICE=pdfwrite "INPUT.pdf" >& /dev/null

Using ‘convert’

Bad quality as of my last test
But you can extract subsets of pages from multiple PDFs easily

convert file1.pdf[0] file2.pdf[0-1,3] output.pdf

Reduce file size/quality

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/screen \
   -dNOPAUSE -dQUIET -dBATCH -sOutputFile=output.pdf input.pdf

where

-dPDFSETTINGS=/screen   --> low quality
-dPDFSETTINGS=/ebook    --> medium quality
-dPDFSETTINGS=/prepress --> full quality