Do you agree with me that Kpdf is the best tool in top 5 PDF readers? At the point in time when I am writing this post, the current version is Kpdf 0.5.8. You can read here to see what are new features of this version. I think that I should write some small tips for this tool. But I will do it latter. Now I will blog for how to change a default PDF reader.
Yesterday, I have installed all tools in top 5 PDF readers. Now, I try to double-click on a PDF document, it is shown up in Acrobat Reader. That means Acrobat Reader is set as the default PDF viewing program in my computer. I don't want to remove them right now. May be I will make another comparison next time. But I prefer Kpdf, so it should be the default one. To make it as the default PDF viewing program I have carried out the following steps in both Ubuntu and Kubuntu.
In Ubuntu Gutsy 7.10.
- Right-click on the PDF document
- Select Properties
Open With" tab - Select KPDF option from the list (see the picture)

- Click "Close" button to finish
- Right-click on the PDF document (or use Alt + Enter)
- Select Properties
- Click on "Tool" button at the right side of "Properties" window
- Move Kpdf to the top of the list of available tools in "Application Preference Order" panel, the result looks like the following picture

- Click "Apply" and "OK" then to confirm changes
- Try to double-click on a PDF document again ... It's OK!
It helped! (Ubuntu 9.04) Thank you!
This works in file manager, but does not work in "Downloads" window (Ubuntu 9.04). After you download a file with firefox, if you click the PDF file, it is still opened by Evince Document Viewer 2.22.2
Great works fine ! Unbuntu 10.4