pdftk
Installing
pdftk can be installed with the following command on Debian-like systems (e.g. Ubuntu):
$ sudo apt-get install pdftk
Reversing Pages
The following example command reverses some of the pages in the pdf in.pdf. It has over 9 pages, and reverses the direction of pages 3-8.
$ pdftk in.pdf cat 1-2 8-3 9-end output out.pdf