Solution 1 :

This is a duplicate question of another one in ROS answers, see here:

Problem :

I ran into this error when running a launch file called turtlemimic.launch

This is the error I received when attempting to run the file in the terminal:

Invalid roslaunch XML syntax: syntax error: line 1, column 3
The traceback for the exception was written to the log file

This is the XML code for the launch file:

       1 <launch>
       3   <group ns="turtlesim1">
       4     <node pkg="turtlesim" name="sim" type="turtlesim_node"/>
       5   </group>
       7   <group ns="turtlesim2">
       8     <node pkg="turtlesim" name="sim" type="turtlesim_node"/>
       9   </group>
      11   <node pkg="turtlesim" name="mimic" type="mimic">
      12     <remap from="input" to="turtlesim1/turtle1"/>
      13     <remap from="output" to="turtlesim2/turtle1"/>
      14   </node>
      16 </launch>

Any advice on how to fix this issue would be greatly appreciated. Thanks!


Comment posted by Zheng Qu

Can you show more of the error message? This launch file looks ok for me. Maybe the error happens somewhere else?