当httpd.conf中DocumentRoot被注释时，httpd内容根目录在哪？如何查询？

Nice question! Let's break this down for your CentOS Linux release 7.4.1708 (Core) and Apache/2.4.6 (CentOS) setup:

1. What's the active DocumentRoot when the httpd.conf line is commented? #

First, let's clear up the confusion around /usr/local/apache/htdocs: that's the default DocumentRoot for source-compiled Apache, but the CentOS yum package uses a standardized filesystem layout instead.

Here's what happens when you comment out the DocumentRoot directive in /etc/httpd/conf/httpd.conf:

• Apache will fall back to its compile-time default value. For your yum-installed Apache, this is almost certainly /var/www/html. You can verify this directly with:

  httpd -V | grep DOCUMENT_ROOT
  

  You should see output like -D DOCUMENT_ROOT="/var/www/html" — that's the directory Apache will use.
• Keep in mind Apache loads additional config files from /etc/httpd/conf.d/ (via the Include conf.d/*.conf line in httpd.conf). If any of those files define a DocumentRoot, that will take precedence over the compile-time default. But by default, none of the stock conf.d files override this setting.

2. Tools to check the active DocumentRoot #

You were right to look at apachectl — it does work, you just need the right flag! Here are the most reliable methods:

Use apachectl/httpd -S (recommended) #

This command outputs a summary of Apache's active configuration, including the DocumentRoot for the default server and any virtual hosts. It's the best option because it accounts for all loaded config files, not just a single one:

apachectl -S
# Or the equivalent direct command:
httpd -S

Look for lines like DocumentRoot "/var/www/html" in the output — that's your active content root directory.

Search all config files manually #

If you want to track down every occurrence of the DocumentRoot directive across your Apache configs, use grep to scan the main config directory and included subdirectories:

grep -r "DocumentRoot" /etc/httpd/conf /etc/httpd/conf.d

This will show you exactly where the directive is defined (if anywhere) across all loaded files.

内容的提问来源于stack exchange，提问作者Randall Stevens