ScriptRunner is an app by Adaptavist which allows the use of Groovy scripts to automate workflows, update fields and perform other actions in Jira.
It also allows users to expand functionality of other apps using their APIs. There are a number of things you can do with Structure too. In the following pages, you will find sample scripts that can be used as is or customized to create your own tailored scripts.
ScriptRunner offers a number of options, which you can access via the ScriptRunner section on the Administration | Add-Ons page.
You can create or change structures by executing a script in the Script Console. You can also set up Script Listeners, so the script is triggered and executed every time some event happens.
Updating a field (ex. label) when checking all issues against a JQL query - This script will update a field (in this case Labels) for all issues that pass a certain JQL query.
You can also add Script Fields as columns in structures.
All of these samples can be implemented as is or customized to fit your specific business needs.