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Contents
  1. Docker tutorial
Getting started
  1. What is Docker
  2. Install Docker
  3. Docker Desktop interface tour
  4. Your first container
  5. Images
  6. Container lifecycle
  7. docker run flags
  8. View logs and debug
Images and Dockerfile
  1. Dockerfile basics
  2. Generate files with docker init
  3. Dockerfile instructions
  4. Build Cache and Optimization
  5. Multi-stage builds
  6. Push to Docker Hub
Data and networking
  1. Volumes and data persistence
  2. Networking and container communication
  3. Environment variables and .env
Docker Compose
  1. Docker Compose Tutorial
  2. compose.yaml syntax
  3. Docker Compose commands
  4. Build a WordPress Site
Real-world examples
  1. Python apps
  2. Node.js apps
  3. Nginx and reverse proxying
  4. MySQL
  5. PostgreSQL
  6. Redis
Operations and advanced topics
  1. Reclaim disk space
  2. Security best practices
  3. Rootless and Podman
  4. Multi-platform images
  5. Build automatically with GitHub Actions
  6. Deploy to a cloud server
  7. Internals
  8. Common error messages
  9. Docker command cheat sheet
Command reference
  1. docker build
  2. docker pull
  3. docker push
  4. docker rmi
  5. docker exec
  6. docker ps
  7. docker stop
  8. docker rm
  9. docker logs
  10. docker stats
  11. docker cp
  12. docker save
  13. docker inspect
  14. docker system
  15. docker volume
  16. docker network
  17. docker compose up
  18. docker compose down

Docker Save Tutorial: Export and Load Images (save, load, export, import)

Use docker save and docker load to move images; docker export and docker import work with a container filesystem, and the resulting image may have different settings. For the basics of images, see Docker images.

Syntax

docker save [OPTIONS] IMAGE [IMAGE...]
docker load [OPTIONS]
docker export [OPTIONS] CONTAINER
docker import [OPTIONS] file|URL|- [REPOSITORY[:TAG]]

Options

CommandOptionDescription
save-o, --output stringWrite to the specified file; if omitted, output to STDOUT
save--platform stringsSave only the specified platforms, separated by commas, such as linux/amd64,linux/arm64/v8
load-i, --input stringRead from the specified tar archive; if omitted, read from STDIN
load--platform stringsLoad only the specified platforms
load-q, --quietSuppress load output
export-o, --output stringWrite the container filesystem to the specified file
import-c, --change listApply Dockerfile instructions to the created image
import-m, --message stringSet the commit message for the imported image
import--platform stringSet the platform if the server supports multiple platforms

Examples

Save, gzip, and load an image

$ docker save -o nginx.tar nginx:1.30-alpine

$ ls -lh nginx.tar
-rw-------    1 root     root       25.7M Oct 25 15:31 nginx.tar

$ docker save nginx:1.30-alpine | gzip > nginx.tar.gz && ls -lh nginx.tar.gz
-rw-r--r--    1 root     root       24.9M Oct 25 15:31 nginx.tar.gz

$ docker load -i nginx.tar.gz
Loaded image: nginx:1.30-alpine

$ docker images nginx
IMAGE               ID             DISK USAGE   CONTENT SIZE   EXTRA
nginx:1.30-alpine   47928bf67eb6       93.5MB           27MB   U
  • docker save -o writes an image to a tar archive; when used directly, the 25.7MB file contains the image data.
  • After gzip compression, this image is 24.9MB, only 0.8MB smaller than the original tar, so the compression effect is limited.
  • docker load -i can read the gzip-compressed archive directly and load nginx:1.30-alpine.
  • After loading, docker images shows the image. Its DISK USAGE is 93.5MB, a different measurement from the archive size.

Import a filesystem with export and import

$ docker export web -o web-fs.tar && ls -lh web-fs.tar
-rw-------    1 root     root       60.5M Oct 25 15:31 web-fs.tar

$ docker import web-fs.tar myweb:snapshot
sha256:56e3f92534ca8c5aedd8de576ae2433f1864d3d3b51de847a8dc8dd7d503da4d

$ docker run --rm myweb:snapshot cat /usr/share/nginx/html/hi.txt
hello

$ docker image inspect -f '{{.Config.Cmd}}' nginx:1.30-alpine
[nginx -g daemon off;]

$ docker image inspect -f '{{.Config.Cmd}}' myweb:snapshot
[]

$ docker run --rm myweb:snapshot
docker: Error response from daemon: no command specified

Run 'docker run --help' for more information
  • docker export writes the web container's filesystem to a tar archive, which docker import then uses to create the myweb:snapshot image.
  • The imported image still contains the files: specifying cat /usr/share/nginx/html/hi.txt reads hello.
  • .Config.Cmd for nginx:1.30-alpine contains nginx -g daemon off;, but .Config.Cmd for myweb:snapshot is an empty array, [].
  • Because the imported image has no default command, running docker run directly returns no command specified; you must specify a command when you run it.

Exercises

Exercise: Save nginx:1.30-alpine as a gzip-compressed archive, then load the image from that file.

Answer 
docker save nginx:1.30-alpine | gzip > nginx.tar.gz
docker load -i nginx.tar.gz

FAQ

What is the difference between docker save and docker export?

docker save archives an image that you can later restore with docker load; docker export exports a container filesystem, and docker import uses it to create a new image.

How much space can gzip compression save on a docker save result?

In this example, the nginx:1.30-alpine tar file is 25.7MB, and the gzip-compressed file is 24.9MB, so the difference is limited.

Why does running docker run directly after docker import show no command specified?

The imported myweb:snapshot has an empty .Config.Cmd array, [], and no default command. Specifying cat /usr/share/nginx/html/hi.txt reads the file, but running it without a command displays no command specified.

Updated October 26, 2026