Ok, I think it’s a bit weird to have a full IDE integration but no simple CLI to do the checks.
We already have ten tools (checkers, linters, formatters…) running with command line. For example for Java checkstyles we can see them in any IDE (with the corresponding extension) but we also have the possibility to run
mvn checkstyle:check to see if the code is clean, which is also the command run on CI before merging a PR.
All this tools also have configuration (the list of rules we want to enforce, the current number of violations, the exact tool version…) that is merged into the project. The maven plugin (or equivalent for other languages) is all the user really need and it is easily installed with the package manager.
As far as I understand Sonar, it is not possible to run this kind of workflow