Splitting a PDF page in two

You can use mutool, a MuPDF command-line tool (sudo apt-get install mupdf-tools):

mutool poster -x 2 input.pdf output.pdf

You can also use -y if you want to perform a vertical split.

Try Gscan2pdf, which you can download from the Software Centre or which you can install from command line sudo apt-get install gscan2pdf.

Open Gscan2Pdf:

1. file > import your PDF file;

   

   Now you have a single page (see the left column):

   

2. then tools > Clean up;

   

3. select double as layout and #output pages as 2, then click OK;

   

4. Gscan2pdf splits your document (among other things, it will also clean it up and deskew it etc.) Now you have two pages:

   

5. Save your PDF file if you're satisfied with the result.

I would use Briss. It lets you select various regions of each page, each of which to turn into a new page.

Another option is ScanTailor. This program is particularly well suited to processing several scans at a time.

apt-get install scantailor

It unfortunately only works on image file inputs, but it's simple enough to convert a scanned PDF to a jpg. Here's a one-liner that I used for converting a whole directory of PDFs into jpgs. If a PDF has n pages, it makes n jpg files.

for f in ./*.pdf; do gs -q -dSAFER -dBATCH -dNOPAUSE -r300 -dGraphicsAlphaBits=4 -dTextAlphaBits=4 -sDEVICE=png16m "-sOutputFile=$f%02d.png" "$f" -c quit; done;

I had screenshots ready to share, but I don't have enough rep to post them.

ScanTailor outputs to tif, so if you want the files back in PDF you can use this to make a PDF for each page.

for f in ./*.tif; do tiff2pdf "$f" -o "$f".pdf -p letter -F; done;

Then you can use this one-liner, or an application like PDFShuffler to merge any or all files into one PDF.

gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=output.pdf *.pdf