Hi,
If you set the SONARLINT_USER_HOME environment variable before starting Eclipse, it will override the default value (= ~/.sonarlint) used by Eclipse. This will certainly work. But I'm not sure that will help you achieve what you want. SonarLint for Eclipse uses SONARLINT_USER_HOME mainly for a global cache of downloaded and unzipped plugins. For example, if you set this variable to /tmp/sonarlint and start Eclipse, then you should see /tmp/sonarlint/plugins directory get created, with all embedded and downloaded plugins extracted there.
Can you tell us more about your goal? What is your expectation by using a custom value for SONARLINT_USER_HOME?
Cheers,
Janos