Useful User Agents

Rather than depend on end users to accurately report the browser used, I look for the user-agent in the web server logs. (Yes, I know it can be spoofed. Power users would be trying different things to resolve their own issues not coming to us.)

Followers of this blog may recall I changed the Weblogic config.xml to record user agents to the webserver.log.

One trick I use is the double quotes in awk to identify just the user agent. This information is then sorting by name to count (uniq -c) how many of each is present. Finally, I sort again by number with the largest at the top to see which are the most common.

grep <term> webserver.log | awk -F\” ‘{print $2}’ | sort | uniq -c | sort -n -r

This is what I will use looking for a specific user. If I am looking at a wider range, such as the user age for hits on a page, then I probably will use the head command to look at the top 20.

A “feature” of this is getting the build (Firefox 3.011) rather than just the version (Firefox 3). For getting the version, I tend to use something more like this to count the found version out of the log.

grep <term> webserver.log | awk -F\” ‘{print $2}’ | grep -c ‘<version>’

I have yet to see many CE/Vista URIs with the names of web browsers. So these are the most common versions one would likely find (what to grep – name – notes):

1. MSIE # – Microsoft Internet Explorer – I’ve seen 5 through 8 in the last few months.
2. Firefox # – Mozilla Firefox – I’ve seen 2 through 3.5. There is enough difference between 3 and 3.5 (also 2 and 2.5) I would count them separately.
3. Safari – Apple/WebKit – In searching for this one, I would add to the search a ‘grep -v Chrome’ or to eliminate Google Chrome user agents.
4. Chrome # – Google Chrome – Only versions 1 and 2.

Naturally there many, many others. It surprised me to see iPhone and Android on the list.