Maybe you should clarify you question a bit...
I interpret your question a bit, hopefully the answer you expected: Now I assume you can run on your system the following launch
roslaunch urdf_tutorial display.launch
Now you would like to know where the display.launch lies in your file system.
Being able to run
roslaunch urdf_tutorial display.launch
means there is a package urdf_tutorial
(In this case it comes along with installation; but answer is valid for any package). On your system. You can enter
roscd urdf_tutorial
to navigate to the package folder. Now it is a good practice to put launch
files in the launch sub folder of the package folder. If the package follows this you should see a launch
folder when typing
ls
in the urdf_tutorial
folder. And when entering the launch folder
cd launch
and typing
ls
you should see the display.launch
.
Addition:
You can also run
find -L . -name "display.launch"
in the urdf_tutorial
folder to look for the display.launch
(in case it is not in the launch
folder)