\r \r

Docker CLI Helper\r

\r This skill explains how to use the Docker command line for common container workflows.\r \r

When to Use\r

\r Use this skill when:\r \r

• The user wants to build or rebuild a Docker image.\r
• The user wants to run a container (one-off or long-running).\r
• The user wants to see which containers/images/volumes exist.\r
• The user wants to stop or remove containers/images.\r
• The user wants to see logs, exec into a container, or check resource usage.\r \r

Requirements\r

\r

• Docker is installed and running.\r
• docker version or docker info works in the user’s shell.\r \r If unsure, suggest the user run:\r \r

docker version\r
```\r
\r
to confirm Docker is available.\r
\r
## Safety Guidelines\r
\r
- Prefer **read-only** or non-destructive commands first:\r
  - `docker ps`, `docker ps -a`\r
  - `docker images`\r
  - `docker logs`\r
  - `docker inspect`\r
- Be cautious with destructive commands:\r
  - `docker rm`, `docker rmi`\r
  - `docker system prune`\r
  - `docker volume rm`\r
- Only recommend destructive cleanups when the user explicitly wants to free resources and understands what will be removed.\r
\r
## Common Workflows\r
\r
### 1. List and inspect containers\r
\r
List running containers:\r
\r
```bash\r
docker ps\r
```\r
\r
List all containers (including stopped):\r
\r
```bash\r
docker ps -a\r
```\r
\r
Inspect a container in detail:\r
\r
```bash\r
docker inspect \x3Ccontainer-id-or-name>\r
```\r
\r
### 2. List and inspect images\r
\r
List local images:\r
\r
```bash\r
docker images\r
```\r
\r
Inspect an image:\r
\r
```bash\r
docker inspect \x3Cimage-id-or-name>\r
```\r
\r
### 3. Build images\r
\r
Build an image from a `Dockerfile` in the current directory:\r
\r
```bash\r
docker build -t \x3Cimage-name>:\x3Ctag> .\r
```\r
\r
Example:\r
\r
```bash\r
docker build -t my-app:latest .\r
```\r
\r
If the `Dockerfile` is in another directory:\r
\r
```bash\r
docker build -t my-app:latest path/to/context\r
```\r
\r
### 4. Run containers\r
\r
Run a container in the foreground:\r
\r
```bash\r
docker run --rm -it \x3Cimage-name>:\x3Ctag>\r
```\r
\r
Run in detached mode (background service):\r
\r
```bash\r
docker run -d --name \x3Ccontainer-name> \x3Cimage-name>:\x3Ctag>\r
```\r
\r
Map ports from container to host:\r
\r
```bash\r
docker run -d --name \x3Ccontainer-name> -p 8080:80 \x3Cimage-name>:\x3Ctag>\r
```\r
\r
Mount a host directory into the container:\r
\r
```bash\r
docker run -d --name \x3Ccontainer-name> -v /host/path:/container/path \x3Cimage-name>:\x3Ctag>\r
```\r
\r
### 5. Stop and remove containers\r
\r
Stop a running container:\r
\r
```bash\r
docker stop \x3Ccontainer-id-or-name>\r
```\r
\r
Remove a stopped container:\r
\r
```bash\r
docker rm \x3Ccontainer-id-or-name>\r
```\r
\r
Stop and remove in one shot (two commands):\r
\r
```bash\r
docker stop \x3Ccontainer-id-or-name>\r
docker rm \x3Ccontainer-id-or-name>\r
```\r
\r
### 6. Remove images\r
\r
Remove an image by ID or name:\r
\r
```bash\r
docker rmi \x3Cimage-id-or-name>\r
```\r
\r
Only suggest this when the user is sure the image is no longer needed.\r
\r
### 7. Logs and exec\r
\r
See logs for a container:\r
\r
```bash\r
docker logs \x3Ccontainer-id-or-name>\r
```\r
\r
Stream logs (follow):\r
\r
```bash\r
docker logs -f \x3Ccontainer-id-or-name>\r
```\r
\r
Execute a shell inside a running container (if it has `/bin/bash`):\r
\r
```bash\r
docker exec -it \x3Ccontainer-id-or-name> /bin/bash\r
```\r
\r
or with `/bin/sh`:\r
\r
```bash\r
docker exec -it \x3Ccontainer-id-or-name> /bin/sh\r
```\r
\r
### 8. Clean up resources\r
\r
Only suggest these when the user explicitly wants cleanup:\r
\r
- Remove all stopped containers:\r
\r
```bash\r
docker container prune\r
```\r
\r
- Remove unused images:\r
\r
```bash\r
docker image prune\r
```\r
\r
- Remove everything unused (containers, networks, images, and optionally volumes):\r
\r
```bash\r
docker system prune\r
```\r
\r
For a more aggressive cleanup, but only if the user confirms:\r
\r
```bash\r
docker system prune -a\r
```\r
\r
## Troubleshooting Tips\r
\r
- If images cannot be pulled, check:\r
  - Network connectivity.\r
  - Registry authentication (if using a private registry).\r
- If ports are already in use, suggest:\r
  - Changing the host port in `-p host:container`.\r
  - Or stopping the process that currently uses the port.\r
- If a container keeps exiting immediately:\r
  - Suggest checking `docker logs \x3Ccontainer>` for errors.\r
  - Inspect entrypoint and command configuration.\r
\r