docker exec

The docker exec command runs a command in a running container.

Syntax

$ docker exec [OPTIONS] CONTAINER COMMAND [ARG...]

Here,

Options

First, start the container if you haven’t already:

$ docker run --name cloudyfox_bash --rm -it cloudyfox /bin/bash

Then, execute the container:

$ docker exec -d cloudyfox_bash touch /tmp/cloudyfoxFile

Here, a new file /tmp/cloudyfoxFile will be created in the background.

Now, execute an interactive bash shell on the container:

$ docker exec -it cloudyfox_bash /bin/bash

It will create a new bash session in the container cloudyfox_bash.

Also, set an environment variable:

$ docker exec -it -e VAR=10 cloudyfox_bash /bin/bash

Note: This $VAR will only be valid on the current bash session.