How to attach the hosting console to the TTY terminal of the default running command on a container using the "docker container attach" command?

If the default running command has a TTY terminal for STDIN and STDOUT, you can attach the hosting console to interact with the running command using the "docker container attach" command.

1. Create a new container with a TTY terminal in interactive mode:

fyicenter$ docker container create --name java --tty --interactive openjdk

2. Start the container with the console attached to the TTY terminal and interact with the default command.

fyicenter$ docker container start --attach --interactive java

java.util.prefs.FileSystemPreferences$1 run
INFO: Created user preferences directory.
|  Welcome to JShell -- Version 12.0.1
|  For an introduction type: /help intro

jshell> 1+2;
fyicenter$1 ==> 3

jshell>

3. Keep this console running and create another console on the hosting system. Then attach the second console to the TTY terminal of the container:

fyicenter$ docker container attach java 

jshell> 3+4;
fyicenter$2 ==> 7

4. Go back to the first console, you see same input and output displayed

jshell> 3+4;
fyicenter$2 ==> 7

4. If you run a "jshell" statement on the first console, you will the same input and output on the second console too.

As you can see, we are able to create a container that runs "jshell" as the default command and attach two consoles to command's TTY terminal.

⇒ "Ctrl-p Ctrl-q" - detach Console

⇐ "docker container start --interactive" - Interact with Container

⇑ "docker container ..." Commands

⇑⇑ Docker Container Platform - Tutorials