ROS2 topic echo Selected field

edit

You can use the --field flag of the ros2 topic echo command. Here is an example:

ros2 topic echo /imu_test --field linear_acceleration

which will give the output

x: 0.0
y: 0.0
z: 0.0
---

You can go further into the field by putting periods after each subsection, so

ros2 topic echo /imu_test --field linear_acceleration.x

will give you

0.0
---

I do not know a ROS2 equivalent of the command you described . However a simple workaround to get a similar behavior could be to use grep for this purpose. You can specify the number of lines that should be visible after your search key with the -A [num lines after match] option. Just set it to the size of the data field of interest.

For example to view the linear acceleration of an sensor_msgs/msg/Imu one could write:

ros2 topic echo /imu_topic | grep -A 3 "linear"
 linear:
   x: 0.0
   y: 0.0
   z: 0.0
(...)