If you don’t own Adobe Acrobat it can be a bit of a hassle to work with PDF files. Sure, there are a number of programs to allow you to print to PDF files without using Acrobat, but how about a free tool to manipulate them?
pdftk is a command-line utility that runs on Windows, Linux, Mac, and other operating systems. It is slightly complex because of the number of features it supports, but works brilliantly for common tasks such as extracting pages from one PDF into their own PDF, combining PDFs, using password protection, and adding watermarks to documents.
pdftk should also be of interest to you if you are a programmer that might need to automate PDF-related tasks. Because it works on multiple platforms, pdftk can be a handy utility to call from web applications that need to manage PDF. The program also has the ability to fill PDF forms from FDF/XFDF formatted files or standard input, so if, for example, you find yourself in the position of wanting to fill a series of PDF forms from something like Microsoft Excel using a VBA macro, pdftk might be just what you need.