Create a script to Add a Label to JIRA issues based on JQL Query

Our team uses Jira and part of our workflow requires adding labels to multiple issues. This is not well supported by Jira: [login to view URL] We use ondemand so we can't use this solution either: [login to view URL] So I would like a script that takes it's credentials from Environment Variables or embedded in the Script, Command Line Arguments for JQL and Label name, and adds the label to every issue connected to the JQL without touching other labels on those issues. This must work with Jira Ondemand.