Log file ruby testing - ruby-on-rails

Question

I have this ruby script and I have a problem on the line 57..
please let me know where is the error
#!/usr/bin/ruby
class CommonLog
# init method takes log filename, computes frequency counts
# for ips, urls & statuses
def initialize(log)
f = File.open(log)
#filename = log
#filesize = f.size
#ip_counts = Hash.new(0)
#url_counts = Hash.new(0)
#status_counts = Hash.new(0)
#total_records = 0
f.readlines.each do |line|
tokens = line.split(' ')
ip = tokens[0]
url = tokens[-4]
status = tokens[-2]
#ip_counts[ip] += 1
#url_counts[url] += 1
#status_counts[status] += 1
#total_records += 1
end
f.close
end
# displays filename and bytesize
def file_info
"Filename: #{#filename}, Bytes Transferred: #{#filesize}"
end
# draws ip histogram
def ip_hist
#ip_counts.each do |ip, freq|
puts "#{ip}: #{'*'*freq}"
end
puts file_info
end
# draws url histogram
def url_hist
#url_counts.each do |url,freq|
puts "#{url} #{'*'*freq}"
end
puts file_info
end
# draws list of statuses
def status_list
msg = ""
sorted_status_codes = #status_counts.keys.sort
sorted_status_codes do |code|
count = #status_counts[code]
pct = ((count.to_f/#total_records)*100).to_i
msg += "#{code}: #{percentage}%\n"
end
puts msg
puts file_info
end
end
def test
log = CommonLog.new('**TEST LOG FILE PATH**')
log.ip_histogram
log.url_histogram
log.status_codes
end
test()
Thank you for your help in advance.. your help would be much appreciated..
The log file is on the server, so I removed the path because you won't be able to reach it ..
Here are the message I get back after I run the file
/1.rb:57:in `status_list': undefined method `keys' for nil:NilClass (NoMethodError)
from ./1.rb:73:in `test'
from ./1.rb:75:in `<main>'