import com.atlassian.jira.component.ComponentAccessor
import com.atlassian.jira.user.util.UserUtil

UserUtil userUtil = ComponentAccessor.getUserUtil()

result = ”

userUtil.getUsers().findAll{it.isActive()}.each{ u ->
result += u.name + “,” + u.displayName + “,” + u.emailAddress + “\r\n”
}

result