Somewhere in my storage I keep PDF files with random content just for fun, for about six years now. The funny thing was, I was revising its owner/group/user permissions and some of them were with a different permission than the usual. A simple chmod command like the following would do the trick: chmod 600 file01.pdf file05.pdf file09.pdf But, as a developer, some times we just have that itch to spend 30 minutes trying an easier way of doing something that usually takes ...