Generate some CLF log lines and add it to a file one line at a time.

log-generate.rb

#!/usr/bin/env ruby

urls = %W(/homepage /page/subpage /page/about_us /section/two /dude /dudette)
ips = %W(127.0.0.1 192.168.0.1 192.168.1.4 192.168.2.3 192.168.5.5 192.168.7.1)
verbs = %W(GET POST PUT DELETE)
results = %W(200 404 403 301 302 500 200 200 200 200 200 200 200)
identities = %W(darron - - - - - - - - - -)

# 127.0.0.1 - frank [10/Oct/2000:13:55:36 -0700] "GET /apache_pb.gif HTTP/1.0" 200 2326

(1..1000).each do
  File.open('log', 'a') do |file|
    t = Time.new
    timestring = t.strftime("%d/%b/%Y:%H:%M:%S")
    bytes = rand(200..256000)
    logline = "#{ips.sample} - #{identities.sample} [#{timestring} -0700] \"#{verbs.sample} #{urls.sample} HTTP/1.0\" #{results.sample} #{bytes}"
    file.puts logline
  end
end