add doc for "--log-file-name" command line argument. (#4087)

* add doc for "--log-file-name" command line argument.

Signed-off-by: Tomoya Fujita <[email protected]>
Co-authored-by: Katherine Scott <[email protected]>

Author: fujitatomoya

source/How-To-Guides/Node-arguments.rst

@@ -67,7 +67,9 @@ The following example will both change the node name and remap a topic (node and
 Logger configuration
 --------------------
 
-See ``--log-level`` argument usage in :doc:`the logging page <../Tutorials/Demos/Logging-and-logger-configuration>`.
+The per-node logging level can be specified using the ``--log-level`` command line argument.
+The executable log file name prefix, which includes all nodes in the executable, can be specified using ``--log-file-name`` command line argument.
+For more information please see :doc:`the logging page <../Tutorials/Demos/Logging-and-logger-configuration>`.
 
 Parameters
 ----------

source/Releases/Release-Jazzy-Jalisco.rst

@@ -94,3 +94,20 @@ Release Timeline
 
 .. [1] The ``ros_base`` variant is described in `REP 2001 (ros-base) <https://www.ros.org/reps/rep-2001.html#ros-base>`_.
 .. [2] The ``desktop`` variant is described in `REP 2001 (desktop-variants) <https://www.ros.org/reps/rep-2001.html#desktop-variants>`_.
+
+New features in this ROS 2 release
+----------------------------------
+
+``ros2cli``
+^^^^^^^^^^^
+
+``--log-file-name`` command line argument
+"""""""""""""""""""""""""""""""""""""""""
+
+It is now possible to use ``--log-file-name`` command line argument to specify the log file name prefix.
+
+.. code-block:: bash
+
+   ros2 run demo_nodes_cpp talker --ros-args --log-file-name filename
+
+See https://github.com/ros2/ros2cli/issues/856 for more information.

source/Tutorials/Demos/Logging-and-logger-configuration.rst

@@ -523,3 +523,15 @@ Then run:
 .. code-block:: bash
 
     ros2 run logging_demo logging_demo_main
+
+Setting the log file name prefix
+--------------------------------
+
+By default, the log file name is based on the executable file name followed by process ID and system timestamp on file creation.
+You can change the log file name prefix to one of your choice using the ``--log-file-name`` command line argument:
+
+.. code-block:: bash
+
+   ros2 run demo_nodes_cpp talker --ros-args --log-file-name filename
+
+This configures the log file name prefix to ``filename``, instead of the executable file name (which is ``talker`` in this case).