On the one hand I have a lot of tar files created with gnu format, and on the other hand I have a tool that only supports pax (aka posix) format. I am looking for an easy way to convert the existing tar files to pax format - without extracting them to the file system and re-create the archives. GNU tar supports both formats. However, I haven't found an easy way to the conversion. How can I convert the existing gnu tar files to pax?