docker-exec

execute commands in a running container

TLDR

Run command in container

$ docker exec [container] [command]

Open interactive shell

$ docker exec -it [container] /bin/bash

Run as specific user

$ docker exec -u [root] [container] [command]

Set environment variable

$ docker exec -e [VAR=value] [container] [command]

Run in specific directory

$ docker exec -w [/path] [container] [command]

SYNOPSIS

docker exec [options] container command [args...]

docker exec runs a new command in a running container's existing environment, creating a new process within the container's namespaces and cgroups. This is fundamentally different from docker run, which creates an entirely new container.The most common use case is opening an interactive shell for debugging with docker exec -it container /bin/bash, which provides direct access to the container's filesystem and running processes. Commands executed via docker exec inherit the container's environment but can be customized with user, working directory, and environment variable options.The --privileged flag grants extended capabilities useful for system administration tasks, though it should be used cautiously as it reduces container isolation.

PARAMETERS

-d, --detach

Run command in background.

-i, --interactive

Keep STDIN open.

-t, --tty

Allocate pseudo-TTY.

-u, --user user

Username or UID.

-w, --workdir dir

Working directory inside container.

-e, --env list

Set environment variables.

--env-file file

Read environment variables from a file.

--detach-keys sequence

Override the key sequence for detaching from the container.

--privileged

Give extended privileges.

CAVEATS

The container must be running. Commands inherit the container's environment. Use -it together for interactive shells. The --privileged flag reduces container isolation and should be used sparingly.