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Logs Related Tips

News Enterprise Logs  Infrastructure

Recommended Links

Syslog Http logs analyzers logger utility

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



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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 )' 

How many hits today?

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

How many unique visitors today?

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

How many hits in a particular day?

What period is covered covered in the log?

Are there missing dates?

How many corrupted log entries?

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

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

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

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?

See in real-time how the log file grows?

Recommended Links

Web site logging and log management

CGI Scripts


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