ROS bag is a nice tool for recording any data that you need to be able to play back at a later time.

The normal usage is:

rosbag record <TOPIC1> ... <TOPIC(N)>

If you want to output to a file with a timestamp and specific prefix:

rosbag record -o <PREFIX> <TOPIC1> ... <TOPIC(N)>

In general we use this format for recording bag files:

rosbag record -a -o <PREFIX>

The normal usage is:

rosbag play <BAG_FILE1> ... <BAG_FILE(N)>

To play back a specific topic from the bag file:

rosbag play --topics <TOPIC1> ... <TOPIC(N)> <BAG_FILE1> ... <BAG_FILE(N)>

To see information about a bag file, rosbag info can help.

rosbag info <BAG_FILE1> ... <BAG_FILE(N)>