Unexpected files showing up with tar on OS X 10.6.4 When packing and unpacking a tar file on OS X today, I find myself looking at things like:

tar tzf ../tanuki-3.5.6.tar.gz  
./._.
./ 
./._bin


I don't think I've ever seem these extra files starting with a '.' before. If I x the file, ls -a does not show them. What are they?
They're resource forks. The Mac's filesystem supports multiple forks, and some Mac files have two, a data fork and a resource fork. Most file systems don't support multiple forks, so tools will split the resource fork into a separate file prefixed with ._.