Docker commands every developer should know

Mar 31, 2024

Here is a list of the most basic 20 Docker commands that every developer should know.

docker version

This command returns the version of both client and server ends of Docker Engine.

Version, OS, Go version, git commit and Built can be different if Docker Client and Daemon (Server) are installed separately on other machines.

docker version [OPTIONS]

% docker version

Client:
 Cloud integration: v1.0.29
 Version:           20.10.20
 API version:       1.41
 Go version:        go1.18.7
 Git commit:        9fdeb9c
 Built:             Tue Oct 18 18:20:35 2022
 OS/Arch:           darwin/amd64
 Context:           default
 Experimental:      true

Server: Docker Desktop 4.13.0 (89412)
 Engine:
  Version:          20.10.20
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.18.7
  Git commit:       03df974
  Built:            Tue Oct 18 18:18:35 2022
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.6.8
  GitCommit:        9cd3357b7fd7218e4aec3eae239db1f68a5a6ec6
 runc:
  Version:          1.1.4
  GitCommit:        v1.1.4-0-g5fd4c4d
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0
 

docker info

This command provides a summarized information about the docker installation, present artifacts and kernel details of the host.

% docker info

docker build

This command is used to make Docker Images out of the written Docker files.

docker build [OPTIONS] PATH | URL

% docker build ~/code/spring-boot-docker/

This command can also be used in combination with image name and version i.e. "spring-boot-docker" and "1".

% docker build -t spring-boot-docker:1 ~/Downloads/spring-boot-docker/ 

docker images

This command returns all of the available images on the Docker host.

docker images [OPTIONS] [REPOSITORY[:TAG]]

% docker images

REPOSITORY           TAG       IMAGE ID       CREATED        SIZE
spring-boot-docker   1         da08505a6a6b   25 hours ago   489MB
spring-boot-docker   1.1       da08505a6a6b   25 hours ago   489MB

The "repository-name" with and without "tag", can be used to find a particular image and see whether it exists or not.

% docker images spring-boot-docker:1.1

REPOSITORY           TAG       IMAGE ID       CREATED        SIZE
spring-boot-docker   1.1       da08505a6a6b   25 hours ago   489MB

The names of the images can be identified under the REPOSITORIES column. If the same image has been built multiple times with multiple tags, it will be listed multiple times as Docker considers it different versions of the same image.

With "--no-trunc" flag, the response will not truncate the Docker Image IDs.

% docker images --no-trunc

REPOSITORY           TAG       IMAGE ID                                                                  CREATED        SIZE
spring-boot-docker   1         sha256:da08505a6a6bd54d61da1094a026fefb0528ece3bb3bf4f24c2b57eb74f30470   25 hours ago   489MB
spring-boot-docker   1.1       sha256:da08505a6a6bd54d61da1094a026fefb0528ece3bb3bf4f24c2b57eb74f30470   25 hours ago   489MB

docker search

docker search [OPTIONS] TERM

This command offers a docker-image search on DockerHub, which works as efficiently as the GUI.

% docker search redis --limit 5

NAME                       DESCRIPTION                                     STARS     OFFICIAL   AUTOMATED
redis                      Redis is an open source key-value store that…   11508     [OK]       
bitnami/redis              Bitnami Redis Docker Image                      231                  [OK]
redis/redis-stack          redis-stack installs a Redis server with add…   20                   
circleci/redis             CircleCI images for Redis                       14                   [OK]
redis/redis-stack-server   redis-stack-server installs a Redis server w…   11  

docker pull

This command pulls a target Docker Image from the desired Docker registry (public or private, by default Docker Hub).

% docker pull bitnami/redis

Using default tag: latest
latest: Pulling from bitnami/redis
1d8866550bdd: Pull complete 
861565d18135: Pull complete 
Digest: sha256:719847095e818f0c1f0320f34902f0d717125458ee832743456fbd08926de657
Status: Downloaded newer image for bitnami/redis:latest
docker.io/bitnami/redis:latest

docker tag

Docker Daemon uses Image IDs to primarily identify the images. Tags (a valid ASCII string) are used as a reference to point to the target image.

This command creates such tags or references that can be used by users to communicate with the daemon.

docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]

% docker tag da08505a6a6b spring-boot-docker:2.1

% docker tag spring-boot-docker:1 spring-boot-docker:3.1

% docker images spring-boot-docker

REPOSITORY           TAG       IMAGE ID       CREATED        SIZE
spring-boot-docker   1         da08505a6a6b   25 hours ago   489MB
spring-boot-docker   1.1       da08505a6a6b   25 hours ago   489MB
spring-boot-docker   2.1       da08505a6a6b   25 hours ago   489MB
spring-boot-docker   3.1       da08505a6a6b   25 hours ago   489MB

The images are stored as repositories with tags.

If we have multiple versions of the same image, the image does not get duplicated, it just gets multiple tags (with corresponding layers if updated any) which are displayed as different images.

docker push

This command is used to push "docker images" to private or public container registries like "Docker Hub" or "jfrog".

Docker requires to follow certain image tagging rules before trying to push it.

Before pushing the image, you need to login with your repository credentials using docker login command.

% docker login -u nkchauhan003 --password-stdin < ~/docker-hub-password
Login Succeeded

% docker tag spring-boot-docker:3.1 nkchauhan003/spring-boot-docker:3.1

% docker push nkchauhan003/spring-boot-docker:3.1 

docker run

The docker run command first creates a writeable container layer over the specified image, and then starts it using the specified command.

A stopped container can be restarted with all its previous changes intact using docker start.

% docker run spring-boot-docker:3.1

docker stop

This docker command stop one or more running containers.

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

% docker stop f9f5e158ec35
f9f5e158ec35

docker ps

This command is used to view a list of all containers.

% docker ps -a

CONTAINER ID   IMAGE                    COMMAND                  CREATED         STATUS                      PORTS      NAMES
8e71fb758418   spring-boot-docker:3.1   "java -jar /spring-b…"   2 minutes ago   Up 2 minutes                8080/tcp   vigorous_mirzakhani
53faaf02d5e3   spring-boot-docker:1     "java -jar /spring-b…"   27 hours ago    Exited (130) 27 hours ago              eloquent_heyrovsky
3cee1b5a878c   spring-boot-docker:1     "java -jar /spring-b…"   27 hours ago    Exited (130) 27 hours ago              cool_haslett

docker inspect

This command invokes inspect() function of the daemon, which provides all of the data regarding the docker image in JSON array format.

% docker inspect spring-boot-docker:3.1

This command is the same for Docker Images and containers.

% docker inspect 8e71fb758418

docker rmi

This command can be used to remove one or more Docker Images addressed by their repository name, tag, or ID.

% docker rmi spring-boot-docker:1
Untagged: spring-boot-docker:1

% docker rmi spring-boot-docker:3.1 --force
Untagged: spring-boot-docker:3.1

% docker rmi -f 2bf604e6f624 61f7ae0c87cd
Untagged: prom/prometheus:latest

When we remove an image, it does not get deleted from the disk (otherwise, the other images would also lose the layers); just the tag gets removed from the metadata.

On the other hand, if there is only one image from a particular repository, the rmi command delete it completely.

% docker images

REPOSITORY                        TAG       IMAGE ID       CREATED      SIZE
nkchauhan003/spring-boot-docker   3.1       da08505a6a6b   2 days ago   489MB
spring-boot-docker                1.1       da08505a6a6b   2 days ago   489MB
spring-boot-docker                2.1       da08505a6a6b   2 days ago   489MB
spring-boot-docker                3.1       da08505a6a6b   2 days ago   489MB
bitnami/redis                     latest    8eaa4bbee65a   3 days ago   114MB

We can remove more than one images from one or more repositories at the same time.

% docker rmi spring-boot-docker:2.1 bitnami/redis

Untagged: spring-boot-docker:2.1
Untagged: bitnami/redis:latest
Untagged: bitnami/redis@sha256:719847095e818f0c1f0320f34902f0d717125458ee832743456fbd08926de657
Deleted: sha256:8eaa4bbee65aa200155d30a40eb1cdb10dfb277748cd6cfba59f83fbd54aae69
Deleted: sha256:8f73e17cfed71f1e5c70f294836f17a4ced569503876f28ca543db8781d350f0
Deleted: sha256:877c59cba30815073ef56303b1b951f0e3e656a4c6170091e66bf53a1973c0c8

In the above command we removed the only bitnami/redis image.

By doing so, the layers of the image will actually be removed since there is no other bitnami/redis variant to keep these layers for.

If you do not mention the Image repository names at all, you can remove all of the images with –a flag.

docker rename

This command renames a container.

docker rename CONTAINER NEW_NAME

% docker ps -a
CONTAINER ID   IMAGE          COMMAND                  CREATED        STATUS                      PORTS     NAMES
8e71fb758418   da08505a6a6b   "java -jar /spring-b…"   21 hours ago   Exited (129) 19 hours ago             vigorous_mirzakhani

% docker rename vigorous_mirzakhani code-burps

% docker ps -a                                
CONTAINER ID   IMAGE          COMMAND                  CREATED        STATUS                      PORTS     NAMES
8e71fb758418   da08505a6a6b   "java -jar /spring-b…"   21 hours ago   Exited (129) 19 hours ago             code-burps

docker exec

This command executes the desired command on the running container.

docker exec [OPTIONS] CONTAINER NAME | ID COMMAND [ARGS]

docker run -d --name redis-cont -p 6379:6379 redis

You can only run a single command with docker exec. Piping or commands combined with && operator will not work.

% docker pull redis

% docker ps   

CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                    NAMES
6dff4ddab591   redis     "docker-entrypoint.s…"   19 seconds ago   Up 19 seconds   0.0.0.0:6379->6379/tcp   cb-redis

% docker exec -it cb-redis sh

# redis-cli
127.0.0.1:6379> SET HELLO WORLD
OK
127.0.0.1:6379> GET HELLO
"WORLD"
127.0.0.1:6379> 

docker stats

This command is used to get live statistics of a target container into the terminal.

% docker stats

CONTAINER ID   NAME         CPU %     MEM USAGE / LIMIT     MEM %     NET I/O       BLOCK I/O   PIDS
45c5e0e2cfd2   cb-redis-1   0.31%     2.637MiB / 3.841GiB   0.07%     726B / 0B     0B / 0B     5
2bff97798376   cb-redis     0.29%     2.504MiB / 3.841GiB   0.06%     1.16kB / 0B   0B / 0B     5

% docker stats cb-redis

CONTAINER ID   NAME       CPU %     MEM USAGE / LIMIT     MEM %     NET I/O       BLOCK I/O   PIDS
2bff97798376   cb-redis   0.30%     2.504MiB / 3.841GiB   0.06%     1.16kB / 0B   0B / 0B     5

docker cp

This command saves you from the trouble of a REST interface for sharing files from host to container and vice-versa.

docker cp /home/nkchauhan003/code/index.html cb-redis:/usr/local/code/index.html