Understanding and Configuring Apache Access Log


Web servers logs provides a lot of information about the web application and user . Apache is very popular web server used by millions of web sites. Apache provides different types of logs like access , error etc. In this tutorial we will look how access log configured and try to understand log format.

Apache Access Log

Apache Access Log provides information about access to the Apache web server. When some one visits the web site or open web application through browser Apache web server will create some log about the request.

Apache Access Log Location

Apache Access Log is stored by default in the following directories. Access log can be opened with a simple text editor like kwrite, gedit etc. or simply cat in the command line.

Ubuntu, Debian,Mint:


CentOS, Fedora, RedHat:


Apache Access Log Formatting

Apachec Access Log provides a lot of useful information about the request and responses to those requests. Apache configuration uses LogFormat directive to define access log format. Default log format is like below.

Here is the meanings of shortcuts.

  • %h ip address of the client
  • %l if exist identity of the client
  • %u userid of the client if the user is authenticated
  • %t date time the request has arrived
  • \"%r\" is the HTTP method the client requested which includes the HTTP verb the URI and HTTP version
  • %>s is the response code the server sends back to the client
  • %b the size of object returned to the client
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Here is an example log for Apache access

Non existing columns will be presented with - .

List Current Access Log Formatting

Access Log format is defined in /etc/apache2/apache2.conf Ubuntu, Debian or /etc/httpd/httpd.conf in CentOS or RedHat systems. We can list current LogFormat directive with the following command.

List Current Access Log Formatting

List Current Access Log Formatting

Interactively Reading Apache Access Log

System administrators generally need to read Apache access log interactively in order to troubleshot. We can use use tail command in order to see Apace access log in real time. We will use following command . We assume access.log resides in /var/log/apache2/access.log

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