Modify the startup parameters roslaunch

 

Start command:

roslaunch beginner_tutorials turtlemimic.launch arg1:=3.0

Query command:

rosparam get /param1

You can see param1 is not the default of 5.0, but 3.0

 

launch the following documents

Note: " $ (Arg arg1)" must be enclosed in double quotes

<launch>
  <arg name="arg1" default="5.0"/> <param name="param1" value="$(arg arg1)" /> <group ns="turtlesim1"> <node pkg="turtlesim" name="sim" type="turtlesim_node"> </node> </group> <group ns="turtlesim2"> <node pkg="turtlesim" name="sim" type="turtlesim_node"/> </group> <node pkg="turtlesim" name="mimic" type="mimic"> <remap from="input" to="turtlesim1/turtle1"/> <remap from="output" to="turtlesim2/turtle1"/> </node> </launch>