Logs Related Tips

This is a collection of one-liners I have found useful. 

One frequent problem with logs is truncation.

This problem often arise with wtmpx

The easiest form of truncation would be

cat /dev/null/ > target.log

or just

:>target.log

NEWS CONTENTS

• 200109 : LogTools 0.1.0 Released ( LogTools 0.1.0 Released, )
• 200109 : How to view log files without line wrapping ? ( )
• 200109 : How many lines (hits) there are in the log file? ( )
• 200109 : How many page views? ( )
• 200109 : How many hits today? ( )
• 200109 : How many unique visitors today? ( )
• 200109 : How many hits in a particular day? ( )
• 200109 : What period is covered covered in the log? ( )
• 200109 : Are there missing dates? ( )
• 200109 : How many corrupted log entries? ( )
• 200109 : How does the line number 15927 or lines 15920 - 15929 look like? ( )
• 200109 : How to figure out the bandwith consumption (in bytes)? ( )
• 200109 : How to delete partial GET requests from the log? ( )
• 200109 : How to compress a selected portion from a log? ( )
• 200109 : See in real-time how the log file grows? ( )

Old News ;-)

Note: Most tips were borrowed from ktmatu - One-liners by Matti Tukiainen. Some are modified. We assume that the web server log files (access_log*) are in Combined Format.

LogTools 0.1.0 Released

December 13, 2011

I finally managed to do the initial public release of LogTools, a set of useful utilities for log data processing. Their current most important feature is the initial version of LogStore, a tamper-proof way to store textual log data especially designed for long-term archival. Note that LogTools perfectly process syslog messages, but can be used for anything that is text-based (like Apache or other application text logs).

I am very happy to finally have the initial release ready. Full details can be found in the release announcement. I initially thought it would become available early last week, but I wanted to create some packages. As I had never done this before, it turned out to become a bit of a problem for me. For the time being, I have settled to do an experimental Debian package via checkinstall. While this is obviously a quick and dirty solution, it enables folks to obtain LogTools via the easy way. Also, I don't think it is too problematic, because in essence only some user-tools are installed that do not affect anything else on the system. But, of course, I'll think about better packaging as the project continues.

At this point, I would be very interested in feedback both on the current tools as well on what would be considered a plus in the future. Please let me know!

How to view log files without line wrapping ?

Less has option -S or --chop-long-lines Causes lines longer than the screen width to be chopped rather than folded. That is, the portion of a long line that does not fit in the screen width is not shown. The default is to fold long lines; that is, display the remainder on the next line.

less -S access_log

How many lines (hits) there are in the log file?

grep 200 access_log | wc -l 

How many page views?

gzip -dc access_log.gz | egrep -vc '(\.gif |\.jpg |\.png )' 
2569

How many hits today?

grep -c `date '+%d/%b/%Y'` access_log
2569

How many unique visitors today?

grep `date '+%d/%b/%Y'` access_log | cut -d" " -f1 | sort -u | wc -l 
1196

How many hits in a particular day?

• Uncompressed log file, e.g. January 1, 2001

  grep -c 01/Jan/2001 access_log 
  2569

• Compressed log file, e.g. January 1, 2001

  gzip -dc access_log.gz | grep -c 01/Jan/2001 
  2569

What period is covered covered in the log?

• Uncompressed log file

  head -1 access_log; tail -1 access_log
  foo.example - - [30/Dec/2000:23:55:25 +0200] "GET /~ktmatu/ ...
  bar.example - - [06/Jan/2001:23:53:37 +0200] "GET /~ktmatu/rates.html ...
  

• Uncompressed log file

  gzip -dc access_log.gz | head -1 ; gzip -dc access_log.gz | tail -1
  foo.example - - [30/Dec/2000:23:55:25 +0200] "GET /~ktmatu/ ...
  bar.example - - [06/Jan/2001:23:53:37 +0200] "GET /~ktmatu/rates.html ...
  

Are there missing dates?

• Uncompressed log file

  cut -d" " -f4 access_log | cut -d"/" -f1 | uniq
  [30
  [31
  [01
  [03
  [04
  [05
  [06
  

• Compressed log file

  gzip -dc wlog0101.gz | cut -d" " -f4 | cut -d"/" -f1 | uniq
  [30
  [31
  [01
  [03
  [04
  [05
  [06
  

How many corrupted log entries?

This is just a very quick and dirty way to check the log.

• Uncompressed log file

  perl -ane 'print $_ if (scalar (split /\"/)) != 7' access_log | wc -l
         7
  

• Compressed log file

  gzip -dc access_log.gz | perl -ane 'print $_ if (scalar (split /\"/)) != 7' | wc -l
         7
  

How does the line number 15927 or lines 15920 - 15929 look like?

• Uncompressed log file

  grep -n '.*' access_log | grep '^15927\:'
  15927:foo.example.com - - [20/Jan/2002:11:23:45 +0200] "GET ...
  

  grep -n '.*' access_log | grep '^1592.\:'
  15920:foo.example.com - - [20/Jan/2002:11:23:40 +0200] "GET ...
  15921:foo.example.com - - [20/Jan/2002:11:23:41 +0200] "GET ...
  15922:foo.example.com - - [20/Jan/2002:11:23:41 +0200] "GET ...
  ...
  

• Compressed log file

  gzip -dc access_log.gz | grep -n '.*' | grep '^15927\:'
  15927:foo.example.com - - [20/Jan/2002:11:23:45 +0200] "GET ...
  

  gzip -dc access_log.gz | grep -n '.*' | grep '^1592.\:'
  15920:foo.example.com - - [20/Jan/2002:11:23:40 +0200] "GET ...
  15921:foo.example.com - - [20/Jan/2002:11:23:41 +0200] "GET ...
  15922:foo.example.com - - [20/Jan/2002:11:23:41 +0200] "GET ...
  ...
  

How to figure out the bandwith consumption (in bytes)?

• Today:

  grep `date '+%d/%b/%Y'` access_log | awk '{ s += $10 } END {print s}'
  13113756
  

• This month:

  grep `date '+../%b/%Y'` access_log | awk '{ s += $10 } END {print s}'
  569477018
  

• Used by Googlebot:

  grep googlebot access_log | awk '{ s += $10 } END {print s}'
  29832233
  

• Used by some rogue user from IP-address 169.254.22.12:

  grep ^169.254.22.12 access_log | awk '{ s += $10 } END {print s}' 
  46760880
  

How to delete partial GET requests from the log?

Partial content requests are usually generated by download managers to speed the downloading of big files and Adobe Acrobat Reader to fetch PDF documents page by page. In this example 206 requests generated by Acrobat reader are deleted so that they don't infate the hit count.

grep -v '\.pdf .* 206 ' access_log > new_log

How to compress a selected portion from a log?

• Use gzip to compress log entries in May 2009

  grep ' \[../May/2009\:' access_log | gzip -9c > access_log-2009-05.gz
  

• Use bzip2 to compress log entries in May 2009

  grep ' \[../May/2009\:' access_log | bzip2 > access_log-2009-05.bz2
  

See in real-time how the log file grows?

• Using tail

  tail -f access_log

• With less you must hit "F" (and Ctrl-C q to quit)

  less access_log

Recommended Links

Web site logging and log management

• Relax - Free, highly configurable web server log file analysis program for referrers. This program recognizes hundreds of search engines and organizes popular keywords and URLs used to get to your site.
• LogPrism - LogPrism is a Perl console script that turns Apache access log files into easy to read color highlighted format where user sessions, error status codes, external referrers and traffic from search engine spiders can be easily distinguished
• Lrdns - Log Reverse Domain Name System converts numeric IP addresses in access log files into textual domain names.
• Dotlog Analysis Tools - A set of Perl scripts designed to dig out information from the cookie data in Blue dot generated log files.
• Ffcat - Fast Forward Cat remembers the end of log file, and prints only the lines added since the script was previously run.

CGI Scripts

• Blue dot - A Perl CGI script that generates Apache combined style access log files for resources on hosts where the log files are not available.
• Contype - A Perl CGI script that sends requested file using user supplied MIME content type to the browser
• TTulos - A Perl script to maintain exam results or other announcements in HTML format.
• Random email address generator

Etc

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotes :  Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce :  Bernard Shaw : Mark Twain Quotes

Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS :  Programming Languages History : PL/1 : Simula 67 : C : History of GCC development :  Scripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month :  How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

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Last modified: January 09, 2020