You're reading the documentation for an older, but still supported, version of ROS 2. For information on the latest version, please have a look at Jazzy.

Migrating Scripts

ROS CLI

In ROS 1 there were individual commands for performing various actions, like rosrun, rosparam, etc.

In ROS 2, there is a single top-level commands called ros2, and all of the actions are sub-commands of that, like ros2 run, ros2 param, etc.

ROS CLI arguments

In ROS 1, arguments to nodes were provided directly on the command-line.

ROS 2 arguments should be scoped with --ros-args and a trailing -- (the trailing double dash may be elided if no arguments follow it).

Remapping names is similar to ROS 1, taking on the form from:=to, except that it must be preceded by a --remap (or -r) flag. For example:

ros2 run some_package some_ros_executable --ros-args -r foo:=bar

We use a similar syntax for parameters, using the --param (or -p) flag:

ros2 run some_package some_ros_executable --ros-args -p my_param:=value

Note, this is different than using a leading underscore in ROS 1.

To change a node name use __node (the ROS 1 equivalent is __name):

ros2 run some_package some_ros_executable --ros-args -r __node:=new_node_name

Note the use of the -r flag. The same remap flag is needed for changing the namespace __ns:

ros2 run some_package some_ros_executable --ros-args -r __ns:=/new/namespace

There is no equivalent in ROS 2 for the following ROS 1 keys:

• __log (but --log-config-file can be used to provide a logger configuration file)

• __ip

• __hostname

• __master

For more information, see the design document.

Quick reference

Feature	ROS 1	ROS 2
remapping	foo:=bar	-r foo:=bar
parameters	_foo:=bar	-p foo:=bar
node name	__name:=foo	-r __node:=foo
namespace	__ns:=foo	-r __ns:=foo