I just wanted to get some pages out of a bigger PDF file. The tool that can be used for this task is called
pdftk. It is in the standard Ubuntu repsitory.
Split the file, so that every page becomes a new PDF file:
pdftk myfile.pdf burst
Extract pages 10 to 12 from bigPDF.pdf:
pdftk bigPDF.pdf cat 10-12 output output.pdf