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15 Essential Docker Commands to Manage Containers Like a Pro

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Hey friend! Docker is an incredible tool that has revolutionized application development and deployment. As a fellow tech geek, I‘m excited to share this comprehensive guide on 15 must-know Docker commands to manage containers.

With the rise of microservices and containerization, Docker has become a critical skill for developers and sysadmins alike. But Docker‘s power comes from mastering its CLI toolset.

15 Docker Commands to Manage Containers [List, Stop, Start, Remove and More]

Let‘s quickly recap what containers and Docker images are:

  • Containers – these are running instances of Docker images. You can think of them like lightweight virtual machines.

  • Images – these are read-only templates used to create containers. Images are composed of file system snapshots and startup commands.

According to Datadog‘s 2022 Container Report, containers adoption has grown significantly:

Docker adoption

With over 79% of companies now running containers in production, it‘s clear these skills are in high demand.

So in this guide, I‘ll share my top 15 Docker commands I use daily as a DevOps engineer to manage containers like a pro. I‘ll cover everything from running and stopping containers to monitoring, debugging and copying files.

Let‘s dive in!

1. docker run

The docker run command is used to launch new containers from images. It‘s one of the most common Docker commands.

docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

Here are some handy flags:

  • -d – Run the container in detached (background) mode
  • --name – Name the container
  • -p – Publish container ports to the host

Let‘s run a new Nginx container:

docker run -d --name my-nginx -p 80:80 nginx

This launches an Nginx container named "my-nginx" in the background and exposes port 80.

Pro tip: The docker run command will automatically pull the image if it‘s not present on the host.

2. docker ps

To view running containers, use the docker ps command: 

docker ps [OPTIONS]

For example:

CONTAINER ID   IMAGE     COMMAND   CREATED         STATUS         PORTS     NAMES
a87ecb4cdf4d   nginx     "nginx"   5 seconds ago   Up 3 seconds   80/tcp    my-nginx

Pass the -a flag to view stopped containers too.

3. docker stop

To stop a running container, use docker stop:

docker stop [OPTIONS] CONTAINER [CONTAINER...]

You can pass a container‘s ID or name:

docker stop my-nginx

This gracefully stops the container by sending a SIGTERM. To forcefully kill it, use docker kill.

4. docker rm

Once containers have stopped, they won‘t be cleaned up automatically. Use docker rm to remove them manually:

docker rm [OPTIONS] CONTAINER [CONTAINER...]

For example:

docker rm my-nginx

This will free up disk space by deleting stopped containers.

5. docker logs

To view container logs, use the docker logs command:

docker logs [OPTIONS] CONTAINER

For example, to follow the live logs for a container:

docker logs -f my-nginx

This is super helpful for debugging issues or monitoring container activity.

6. docker exec

To execute a command inside a running container, use docker exec: 

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

For example, to open a Bash shell inside your Nginx container:

docker exec -it my-nginx bash

The -it provides an interactive terminal. This allows you to explore and troubleshoot containers.

7. docker cp

The docker cp command lets you copy files between containers and the local filesystem:

docker cp [OPTIONS] CONTAINER:SRC_PATH DEST_PATH|-
docker cp [OPTIONS] SRC_PATH|- CONTAINER:DEST_PATH

For example, to copy your Nginx config from the container to your current directory:

docker cp my-nginx:/etc/nginx/nginx.conf ./nginx.conf

This bidirectional copy works great for backing up files or pushing config changes.

8. docker diff

Want to see filesystem changes within a container? Use docker diff:

docker diff [OPTIONS] CONTAINER

This shows changed files and directories since the container was started from the image. Here‘s sample output:

A /tmp/new_file
C /var
D /usr/local/bin

Useful for inspecting container state and verifying config changes.

9. docker top

To see running processes inside a container, use docker top:

docker top [OPTIONS] CONTAINER [ps OPTIONS]

For example: 

docker top my-nginx

UID    PID   PPID  C STIME  TTY   TIME       CMD
root   132   0     0 02:34  ?     00:00:00   nginx: master process nginx -g daemon off;
101    158   132   0 02:34  ?     00:00:00   nginx: worker process   
root   172   0     0 02:34  ?     00:00:00   nginx: cache manager process

This provides insight into how containers function and resource usage.

10. docker stats

To monitor real-time container resource usage statistics, use docker stats:

docker stats [OPTIONS] [CONTAINER...]

For example:

CONTAINER           CPU %               MEM USAGE / LIMIT     MEM %              
my-nginx             0.00%               24.4MiB / 1.945GiB   1.24%

This gives you metrics on CPU, RAM utilization, disk I/O and network traffic. Helpful for performance tuning and bottleneck identification.

11. docker inspect

The docker inspect command provides detailed information about a container: 

docker inspect [OPTIONS] NAME|ID [NAME|ID...]

This includes the container config, runtime details, network settings, mounted volumes, and more.

Here‘s a snippet:

"Config": {
  "Hostname": "a87ecb4cdf4d",
  "Env": [
    "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
    "NGINX_VERSION=1.21.3"
  ],
  "ExposedPorts": {
    "80/tcp": {}
  }
},  
"Name": "/my-nginx",
"RestartCount": 0,
"State": {
  "Status": "running",
  "Running": true,
},
"NetworkSettings": {
  "Ports": {
    "80/tcp": [
      {
        "HostIp": "0.0.0.0",
        "HostPort": "80"
      }
    ]
  }  
}

Great for debugging and understanding what‘s happening under the hood.

12. docker rename

You can rename a container with the docker rename command:

docker rename CONTAINER NEW_NAME

For example:

docker rename my-nginx my-new-nginx

Simple but useful for keeping your environment organized when managing multiple containers.

13. docker export

To export a container‘s filesystem into a tar archive, use docker export:

docker export [OPTIONS] CONTAINER

For example:

docker export my-nginx -o my_nginx.tar

This exports the container into a tarball that can be shared or reimported.

14. docker kill

To forcefully kill a running container, use docker kill:

docker kill [OPTIONS] CONTAINER [CONTAINER...]

This instantly sends a SIGKILL signal, terminating the container immediately. Compare this to docker stop which gracefully stops the process.

15. docker system

Finally, docker system provides system-wide management capabilities:

docker system COMMAND

For example, docker system prune allows you to clean up unused containers, images, volumes, and networks.

Other subcommands let you manage disk usage, check Docker health, view real-time events, and more.

Key Takeaways

There you have it – my top 15 Docker commands for managing containers like a pro!

Here are some key takeaways:

  • docker run launches new containers from images
  • docker ps and docker logs allow monitoring and debugging
  • docker stop and docker kill stop running containers
  • docker exec runs commands inside containers
  • docker cp copies files between containers and the host
  • docker stats and docker top give resource usage metrics
  • docker inspect provides detailed container information
  • docker system handles system-wide tasks like prune

With robust container management capabilities, Docker enables you to build, deploy, monitor, and maintain applications easily. These commands are essential knowledge for developers and sysadmins working with containerized environments.

For further learning, I suggest checking out Docker‘s official command line reference. And let me know if you have any other favorite container management tips!

Hope this guide helps you become a Docker pro. Now go forth and containerize all the things!

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