What is the most important configuration file used in Apache on an Amazon EC2 linux instanc code example

Example 1: how to configure httpd in amazon ec2 instance

[ec2-user ~]$ sudo service httpd start

Example 2: how to configure httpd in amazon ec2 instance

[ec2-user ~]$ sudo yum install -y httpd24 php56 php56-mysqlnd

Example 3: how to configure httpd in amazon ec2 instance

[ec2-user ~]$ sudo chgrp -R www /var/www