How do I edit a file after I shell to a Docker container?

Question

I successfully shelled to a Docker container using:

docker exec -i -t 69f1711a205e bash 

Now I need to edit file and I don't have any editors inside:

root@69f1711a205e:/# nano bash: nano: command not found root@69f1711a205e:/# pico bash: pico: command not found root@69f1711a205e:/# vi bash: vi: command not found root@69f1711a205e:/# vim bash: vim: command not found root@69f1711a205e:/# emacs bash: emacs: command not found root@69f1711a205e:/# 

How do I edit files?

Answer 1

As in the comments, there's no default editor set - strange - the $EDITOR environment variable is empty. You can log in into a container with:

docker exec -it <container> bash 

And run:

apt-get update apt-get install vim 

Or use the following Dockerfile:

FROM  confluent/postgres-bw:0.1  RUN ["apt-get", "update"] RUN ["apt-get", "install", "-y", "vim"] 

Docker images are delivered trimmed to the bare minimum - so no editor is installed with the shipped container. That's why there's a need to install it manually.

EDIT

I also encourage you read my post about the topic.

Answer 2

If you don't want to add an editor just to make a few small changes (e.g., change the Tomcat configuration), you can just use:

docker cp <container>:/path/to/file.ext . 

which copies it to your local machine (to your current directory). Then edit the file locally using your favorite editor, and then do a

docker cp file.ext <container>:/path/to/file.ext 

to replace the old file.