Could you clarify when "-it" should be used in a "docker run" command?

Question

If I use

docker run  myimage /bin/bash -c "pwd"

or

docker run  -it myimage /bin/bash -c "pwd"

the results are the same. Then, what is the sense of "-it"? I learned that "-i" is for interactive, "-t" is for tty. But those are abstract nouns for me. Could you clarify when "-it" should be used in a "docker run" command?

Arfat Binkileb · Answer 1 · 2021-03-23T14:57:03.583

1

You can use -it flag when you want interact with container. For example:

 $ docker run -it myimage /bin/bash

this will give you a shell inside container and keep you connected to bash

/ #

And this will run any command but close the connection and drop you to your host machine's shell

 $ docker run  myimage /bin/bash -c "pwd"

/ 
test@host $

So you would use -it to connect and execute more commands inside container.

and finally exit out of container

/ # exit
exited

edited Mar 23 '21 at 14:57

answered Mar 23 '21 at 09:30

Arfat Binkileb

641
4
18

1

You can use -it flag when you don't want interact with container - Are you sure about that? When you access a container, you are interacting with it. – ale917k Mar 23 '21 at 09:41
Thanks. What does it mean "when you don't want interact with container"? – zell Mar 23 '21 at 09:50
Sorry. It was a typo. Fixed now. – Arfat Binkileb Mar 23 '21 at 14:57

score 1 · Accepted Answer · answered Mar 23 '21 at 09:30

Mentioning the docs,

For interactive processes (like a shell), you must use -i -t together in order to allocate a tty for the container process.

Essentially what that does is adding a terminal driver which allows you to interact with your container as a terminal session.

After running your container, you can run docker ps to get the hash id of your container which you can then access by running:

docker exec -it containeridhash sh

Could you clarify when "-it" should be used in a "docker run" command?

2 Answers2