How to check SHA numbers?

To check the SHA numbers (hashes) of Docker image layers, you can use the docker inspect command. Here’s how to do it:

Steps to Check SHA Numbers

Open Your Terminal: Make sure you have Docker installed and running.
Run the Inspect Command: Use the following command, replacing image_name with the name of your Docker image:
```
docker inspect --format='{{.RootFS.Layers}}' image_name
```
For example, if your image is named custom-nginx, you would run:
```
docker inspect --format='{{.RootFS.Layers}}' custom-nginx
```
View the Output: The command will output a list of SHA256 hashes corresponding to the layers of the specified image. It will look something like this:
```
[ "sha256:abc123...", "sha256:def456...", ... ]
```

Example

If you want to inspect the SHA numbers of an image named my-image, you would execute:

docker inspect --format='{{.RootFS.Layers}}' my-image

Additional Information

Full Inspect Command: If you want more detailed information about the image, you can simply run:
```
docker inspect my-image
```
This will provide a comprehensive JSON output, including the SHA numbers under the RootFS section.
Using jq: If you have jq installed, you can format the output for better readability:
```
docker inspect my-image | jq '.[].RootFS.Layers'
```

Summary

By using the docker inspect command, you can easily check the SHA numbers of the layers in a Docker image. This can help you verify integrity, troubleshoot issues, or manage layers effectively.

If you have more questions or need further assistance, feel free to ask!