It's one time use, not on to run in the background. File doesn't
contain any information about time.
Then it's a lot harder, no utility does this out of the box because if it did, it would imply that it knew about the files contents 10 seconds ago. But, there is nothing magical about "10 seconds" that would mean write data is kept/buffered for that long (unless there is some secondary logging about what it wrote to the log file, and when).
Your best bet is to either:
- Run the commmand that Laykes gave or an equivalent like
tail -s 10 -f FILE so it outputs the contents of the file in 10 second blocks.
- Mark the log file itself:
echo '-- MARKER --' >> FILE and check back for what you want.
But, either way, you'll need to roll your own solution.