If you’re new to Linux, and to Apache, chances are you are going to make a couple of mistakes when updating configuration files.
Fortunately there are a few commands to help you fix these issues before you make the changes matter.
With most changes to the Apache configuration file, you are required to restart Apache for the changes to take affect, but if you’ve made a mistake in your reconfiguration then Apache will still restart with those mistakes present, or what’s worse it won’t restart at all and you’ll be without a website.
That’s when a nice little command like
sudo /usr/sbin/apache2ctl configtest
or,
sudo /usr/sbin/apachectl graceful
come in very handy. These commands return any error messages that you might receive if you were to reboot.
Once you’re happy the changes you have made are right to go, use the trusty
sudo /etc/init.d/apache2 restart