Starting and Stopping httpd APACHE in CENTOS

https://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-apache-startstop.html

21.3. Starting and Stopping httpd

After installing the httpd package, review the Apache HTTP Server's documentation available online at http://httpd.apache.org/docs/2.2/.
The httpd RPM installs the /etc/init.d/httpd script, which can be accessed using the /sbin/service command.
Starting httpd using the apachectl control script sets the environmental variables in /etc/sysconfig/httpd and starts httpd. You can also set the environment variables using the init script.
To start the server using the apachectl control script as root type:

apachectl start

You can also start httpd using /sbin/service httpd start. This starts httpd but does not set the environment variables. If you are using the default Listen directive in httpd.conf, which is port 80, you will need to have root privileges to start the apache server.
To stop the server, as root type:

apachectl stop

You can also stop httpd using /sbin/service httpd stop. The restart option is a shorthand way of stopping and then starting the Apache HTTP Server.
You can restart the server as root by typing:

apachectl restart 
or:
/sbin/service httpd restart

Apache will display a message on the console or in the ErrorLog if it encounters an error while starting.
By default, the httpd service does not start automatically at boot time. If you would wish to have Apache startup at boot time, you will need to add a call to apachectl in your startup files within the rc.N directory. A typical file used is rc.local. As this starts Apache as root, it is recommended to properly configure your security and authentication before adding this call.
You can also configure the httpd service to start up at boot time, using an initscript utility, such as /sbin/chkconfig, /usr/sbin/ntsysv, or the Services Configuration Tool program.
You can also display the status of your httpd server by typing:

apachectl status

The status module mod_status however needs to be enabled in your httpd.conf configuration file for this to work. For more details on mod_status can be found on http://httpd.apache.org/docs/2.2/mod/mod_status.html.