Reading the last n lines of a file in Ruby?

Question

I need to read the last 25 lines from a file (for displaying the most recent log entries). Is there anyway in Ruby to start at the end of a file and read it backwards?

Answer 1

Is the file large enough that you need to avoid reading the whole thing? If not, you could just do

IO.readlines("file.log")[-25..-1]

If it is to big, you may need to use IO#seek to read from near the end of the file, and continue seeking toward the beginning until you've seen 25 lines.