How to Use Docker Run -it: Interactive Container Sessions

Use docker run -it to start a Docker container in interactive mode with a terminal attached. The -i flag keeps the input open, and -t allocates a terminal, letting you interact with the container directly.

Syntax

The basic syntax of docker run -it is:

• docker run: Command to create and start a container.
• -i: Keeps STDIN open so you can send input to the container.
• -t: Allocates a pseudo-TTY (terminal) for interactive shell.
• [image]: The Docker image to run.
• [command]: Optional command to run inside the container.

bash

docker run -it [image] [command]

Example

This example runs an Ubuntu container interactively and opens a bash shell inside it. You can type commands directly inside the container.

bash

docker run -it ubuntu bash

Output

root@<container-id>:/# 

Common Pitfalls

Common mistakes when using docker run -it include:

• Omitting -i or -t, which prevents interactive input or terminal allocation.
• Running a container without a shell command, which may cause the container to exit immediately.
• Not using an image that supports interactive shells.

bash

docker run ubuntu
# Container exits immediately because no interactive shell is started

docker run -it ubuntu bash
# Correct: starts interactive bash shell

Quick Reference

Flag	Description
-i	Keep STDIN open for interactive input
-t	Allocate a pseudo-TTY (terminal)
-d	Run container in detached mode (background)
--rm	Automatically remove container when it exits

Key Takeaways

Use docker run -it to start containers with interactive terminal access.

The -i flag keeps input open; -t creates a terminal interface.

Always specify a shell command like bash to keep the container running interactively.

Without -it, you cannot interact with the container's shell.

Use --rm with -it to clean up containers after exit.