How can I view the complete httpd configuration?

As noted by arco444, you can use apachectl -S to display an overview of the VirtualHosts currently running from the configs, and apachectl -M to display all currently loaded modules - I'm not aware of a tool to display the verbose output of all configs parsed (and which order they were parsed in) at launch of httpd, but I would recommend that you familiarise yourself with the general structure of the httpd config files:

• Apache 2.2 - General structure of the httpd config files
• Apache 2.4 - General structure of the httpd config files

Of particular note to your question: the 'main' apache config file is located in /etc/httpd/conf/httpd.conf (in the region of line 221 on a default httpd installation from the repos included in CentOS 6, which I assume you are using based on your post tags), and the 'supplementary' config files are located in /etc/httpd/conf.d and require to be included explicitly in the main config file. For example, if you search the httpd.conf file for the term 'Include', you will find the line Include conf.d/*.conf which is what includes all files of extension .conf in the subdirectory conf.d - in alphabetical order, so you will want to familiarise yourself with the importance of config file parsing at some point if possible.

As an aside, if you are using a shell based text editor such as vim, I suggest that you enable line numbering and syntax highlighting by default so that such lengthy config files are a bit easier to parse yourself and navigate - in the case of vim, you'd do so by creating a file in your home directory called .vimrc (or append to an existing one) and add the following lines:

set nu
syntax on

As described in the Apache HTTP Server Documentation

If the config define -DDUMP_CONFIG is set, mod_info will dump the pre-parsed configuration to stdout during server startup.

httpd -DDUMP_CONFIG -k start

DUMP_CONFIG requires mod_infoenabled: a2enmod info!

In Ubuntu do the following

sudo apache2ctl -DDUMP_CONFIG

If you want to strip the line numbers do

sudo apache2ctl -DDUMP_CONFIG | grep -vE "^[ ]*#[ ]*[0-9]+:$"

or redirect to a file

sudo apache2ctl -DDUMP_CONFIG | grep -vE "^[ ]*#[ ]*[0-9]+:$" > /path/to/dump.conf

Known Limitations

mod_info provides its information by reading the parsed configuration, rather than reading the original configuration file. There are a few limitations as a result of the way the parsed configuration tree is created:

• Directives which are executed immediately rather than being stored in the parsed configuration are not listed. These include ServerRoot, LoadModule, and LoadFile.
• Directives which control the configuration file itself, such as Include, and are not listed, but the included configuration directives are.
• Comments are not listed. (This may be considered a feature.)
• Configuration directives from .htaccess files are not listed (since they do not form part of the permanent server configuration).
• Container directives such as are listed normally, but mod_info cannot figure out the line number for the closing .
• Directives generated by third party modules such as mod_perl might not be listed.