I always forget, and this blog is meant to help me remember.
Found in Tar’s manual, are these simple directives:
Have a file called file.tar, do:
tar -xf file.tar full/path/without/trailing/slashes
It can be a file or directory. You can have a list of files, such:
tar -xf file.tar home/me home/you home/us/important-file
Should do the trick.