2.2. Directory Layout Structure
We refer to a variety of special files and directories throughout this book. Although there is a standard Apache server layout, this standard has changed over time and many sites have extensively customized their layout. Furthermore, some operating systems which come with Apache preinstalled choose a nonstandard directory structure that is more consistent with the OS's way of doing things. To avoid potential confusion, we explain the directory structure we use in this book. If you are installing Apache and mod_perl for the first time, you might want to follow the suggestions given here for convenience.
Server root directory
This is the top of the Apache server tree. In a typical setup, this directory contains a bin directory for the httpd Apache executable and the apachectl control utility; the configuration and log directories (conf and logs ); a directory for executable CGI scripts, cgi-bin; a directory for dynamically loaded modules, libexec; header files for building C-language modules, include; and the document root directory, htdocs.
 The directory layout we describe here is the default Apache layout. Other predefined layouts may be configured with the Apache configuration option --with-layout=Type where Type can be GNU or another user-defined layout. Consult the Apache installation documention for more details.
The default server root directory on Unix machines is /usr/local/apache, which we'll use throughout the book. However, ...