1️⃣ Record all topics

ros2 bag record -a

• a = record all topics currently being published.
• Output will go into a folder like rosbag2_<date_time>/.

2️⃣ Record specific topics

ros2 bag record /turtle1/cmd_vel /turtle1/pose

• Only records the topics you list.

3️⃣ Playback the bag

ros2 bag play <bag_folder>

• Replays messages as if they were being published live.
• Useful for testing algorithms without running hardware.

4️⃣ Inspect a bag

ros2 bag info <bag_folder>

• Shows what topics, message types, and time span are stored.

5️⃣ Options

• -output <name> → name the bag folder:

  ros2 bag record -a --output my_experiment