How to get ENV variable when doing Docker Inspect

Question

I wonder how I get an Environment variable from docker inspect.

when i run

docker inspect -f \"{{.Config.Env.PATH}} \" 1e2b8689cf06

Answer 1

This doesn't seem to be possible, you can list the environment variables but not just one.

From the docker commit doc

$ sudo docker inspect -f "{{ .Config.Env }}" c3f279d17e0a
[HOME=/ PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin]

$ sudo docker commit --change "ENV DEBUG true" c3f279d17e0a  SvenDowideit/testimage:version3
f5283438590d

$ sudo docker inspect -f "{{ .Config.Env }}" f5283438590d
[HOME=/ PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin DEBUG=true]

You can print them:

docker inspect --format='{{range .Config.Env}}{{println .}}{{end}}'

(as in)

$ docker inspect --format='{{range .Config.Env}}{{println .}}{{end}}' c3fa3ce1622b
HOME=/
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

Add a grep PATH and you could get only the PATH=xxx value.

---

user2915097 mentions in the comments jq, a lightweight and flexible command-line JSON processor, used in the article "Docker Inspect Template Magic " to format nicely the needed field:

docker inspect -f '{{json .State}}' jenkins-data | jq '.StartedAt' 
  "2015-03-15T20:26:30.526796706Z"