Yesterday I found myself trying to compare multipage PDF documents with code samples. You can imagine how painful and frustrating it was, so I went googling to check what can help me in this task. It appears that there are free alternatives to obvious, but really expensive solution of purchasing Adobe Acrobat license.

My favorite solution for now is WinMerge (yes, it can compare files), accompanied with the xdocdiff plugin that enhances WinMerge with the understanding of the “inner works” of several popular document types.

Here is the installation and configuration procedure:

1. Download and install WinMerge according to the instructions. Start WinMerge to make sure it is installed correctly.
2. Download xdocdiff plugin and extract it to some local folder.
3. Move extracted files according to the instructions in the xdocdiff README file. Ignore the line that says to enable “Automatic Unpacking” – it is still disabled.
4. Go to “Plugins” → “List…” and select “Enable plugins” checkbox, then click “OK”.
5. Now you can choose “Plugins” → “Automatic Unpacking” (it is already enabled).

For those who are not familiar with WinMerge – go to “File” → “Open…” and select to files to compare.

Hat tip to this SuperUser answer, that helped me to figure out the correct installation procedure.