This is the ros2 diagnostics echo utility command which displays the content, by default, of /diagnostics_agg topic in a nicely formatted and colorized output.
Run ros2 diagnostics echo to fetch and output diagnostics.
Run ros2 diagnostics echo -h/--help to print all available command arguments.
The command outputs the diagnostics with the following format: [ level ] name - message
By default, level is printed in color to match their priority level.
The --no-color switch is provided to disable coloring.
The -f/--follow switch is provided to follow the diagnostics continously.
The -d/--detail switch is provided to display timestamp, hardware_id and values.