Split the pages out of a PDF, or merge PDFs into one

Using the free open source program PDF Toolkit, you can operate on PDFs quite easily.

Install the open-source PDF Toolkit

Get the PDF Toolkit package, available for Windows, Mac OSX 10.3+ (or build from source for earlier Mac OSs) and Linux.

It’s in the Ubuntu repositories:

sudo apt-get install pdftk 

Split pages from a PDF

To split out pages 10-15 and page 19 of whole.pdf into a separate PDF, piece.pdf, run

pdftk whole.pdf cat 10-15 19 output piece.pdf

Merge multiple PDFs into one

To combine first.pdf, second.pdf, and third.pdf into big.pdf, use

pdftk first.pdf second.pdf third.pdf cat output big.pdf

Other examples here