Also handle SIGTERM gracefully (#2747)

Signed-off-by: Erling Rennemo Jellum
Signed-off-by: erlingrj <erling.jellum@gmail.com>
Signed-off-by: erling <erling.jellum@gmail.com>
Co-authored-by: Addisu Z. Taddese <addisu@openrobotics.org>
Co-authored-by: Ian Chen <ichen@openrobotics.org>

src/cmd/cmdsim.rb.in

@@ -554,9 +554,19 @@ See https://github.com/gazebosim/gz-sim/issues/168 for more info."
                           options['render_engine_gui_api_backend'])
         end
 
-        Signal.trap("INT") {
+        # Handle SIGINT and SIGTERM signals
+        def handle_signal(guiPid, serverPid)
           self.killProcess(guiPid, "Gazebo Sim GUI", 5.0)
           self.killProcess(serverPid, "Gazebo Sim Server", 5.0)
+        end
+
+        Signal.trap("INT") {
+          handle_signal(guiPid, serverPid)
+          return 1
+        }
+
+        Signal.trap("TERM") {
+          handle_signal(guiPid, serverPid)
           return 1
         }