Do not use for loops for package removal on debian-based systems

[ghost]

Description

In the docker engine installation instructions, it is advised to remove unofficial packages in the following way:

for pkg in <packages>; do sudo apt-get remove $pkg; done

This invokes apt-get many times, resulting in having to confirm every uninstallation.

This PR changes such instructions to the following, easier-to-read and easier-to-execute format:

sudo apt-get remove <packages>

Reviews

• Technical review
• Editorial review
• Product review

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[thaJeztah]

I left a comment, but perhaps someone has good suggestions to "have both" 😅

[thaJeztah]

Using a loop was an intentional change; without a loop, this command may fail, and some packages still installed; see

• engine: fix apt-get remove command for uninstall preexisting packages #17415
• "apt-get remove" command doesn't remove installed packages if a package isn't found #17405

resulting in having to confirm every uninstallation.

Yeah, that's rather inconvenient, and II can see that being inconvenient. Not sure what a better solutions would be for that, without this step becoming overly complex. We could detect which packages are installed, but probably that would make it either an extra step, or "complex",

If your situation allows it, and needs to be run non-interactively, it's of course use your own variant 😅

[ghost]

I've just looked to these issues, and tested a few package removal combinations. Turns out, apt-get only fails if a package does not exist. That is, when there is no such package in the package repository. When a real package is not installed, apt continues normally:

$ sudo apt-get remove docker.io podman-docker
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package 'podman-docker' is not installed, so not removed
...
The following packages will be REMOVED:
  docker.io
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 151 MB disk space will be freed.
Do you want to continue? [Y/n] 

According to docs itself, these guides are for debian 11 or higher, ubuntu 20.04 or higher, and their derivatives. All of the packages in the changed lines are in the repositories already. So, I think my change would not break something, or would it?

In #17405, the problem was related with nonexistent docker-engine package. Looks like that package is already removed from here.

[dvdksn]

I'm not sure when the docker-engine package was removed from here but indeed, apt-get will only skip and not error out if the package exists but was not installed. Given that we don't list any nonexistent packages here, I think we should be safe to remove the for-loop now. WDYT @thaJeztah?

Besides, it's been a pretty long time since we shipped packages under those nonexistent (e.g. docker-engine) names, no? We're only backwards compatible with oldstable, so this should be fine I think.

[docker-robot]

Thanks for the pull request. We'd like to make our product docs better, but haven’t been able to review all the suggestions.
As our docs have also diverged, we do not have the bandwidth to review and rebase old pull requests.

If the updates are still relevant, review our contribution guidelines and rebase your pull request against the latest version of the docs, then mark it as fresh with a /remove-lifecycle stale comment.
If not, this pull request will be closed in 30 days. This helps our maintainers focus on the active pull requests.

Prevent pull requests from auto-closing with a /lifecycle frozen comment.

/lifecycle stale