How does image in docker Link Multiple Tags to the Same id

  docker, question

How can multiple image of docker point to the same id?

Such as ubuntu

ubuntu                saucy               9f676bd305a4        5 weeks ago         178 MB
 ubuntu                13.10               9f676bd305a4        5 weeks ago         178 MB
 ubuntu                raring              eb601b8965b8        5 weeks ago         166.5 MB
 ubuntu                13.04               eb601b8965b8        5 weeks ago         166.5 MB
 ubuntu                quantal             5ac751e8d623        5 weeks ago         161 MB
 ubuntu                12.10               5ac751e8d623        5 weeks ago         161 MB
 ubuntu                10.04               9cc9ea5ea540        5 weeks ago         180.8 MB
 ubuntu                lucid               9cc9ea5ea540        5 weeks ago         180.8 MB
 ubuntu                12.04               9cd978db300e        5 weeks ago         204.4 MB
 ubuntu                latest              9cd978db300e        5 weeks ago         204.4 MB
 ubuntu                precise             9cd978db300e        5 weeks ago         204.4 MB

For example, 12.04, precision and latest all point to 9cd978db300e.

If you commit yourself, how can you achieve this effect? I want to point the original latest tag to the latest tag every time I submit a new tag.

I’ve solved it myself. Just use tag

docker tag eb601b8965b8 ubuntu:latest