File structure question about ROS

edit

I am installing a turtlebot arm onto my turtlebot and one of the instructions in the tutorial is :

Setting up the URDF

Next, we have to set up the TurtleBot's hardware description file (URDF) to include the arm. This is done through the TurtleBot bringup script in /etc/ros/turtlebot.

On the TurtleBot, edit /etc/ros/turtlebot/bringup.launch in your favorite text editor and change it to resemble this:

<launch>
  <param name="turtlebot_node/gyro_scale_correction" value="1.0"/>
  <param name="turtlebot_node/odom_angular_scale_correction" value="1.0"/>

  <include file="$(find turtlebot_bringup)/minimal.launch">
    <arg name="urdf_file" value="$(find xacro)/xacro.py '$(find turtlebot_arm_description)/urdf/arm.urdf.xacro'" />
  </include>

</launch>

The line

<arg name="urdf_file" value="$(find xacro)/xacro.py '$(find turtlebot_arm_description)/urdf/arm.urdf.xacro'" />

tells the TurtleBot to use the urdf that includes the arm from the turtlebot_arm_description package.

However, my /etc directory does not contain a ros folder. There is a ros folder within my /opt file that has a subdirectory electric/stacks/turtlebot/turtlebot_bringup which contains the following files and folders:

Files: app_manager.launch CMakeLists.txt kinect.launch Makefile minimal.launch ROS_NOBUILD
mainpage.dox manifest.xml

Folders: upstart bin config mock_apps scripts

Does anyone have an idea which file I should be modifying? Thanks!