Install PHP 7 on AWS EC2 Linux Instance

aws-ec2-php7.2-script.sh

# Pick the topic name or number from the list below

#sudo amazon-linux-extras list
#  0  ansible2   disabled  [ =2.4.2 ]
#  1  emacs   disabled  [ =25.3 ]
#  2  memcached1.5   disabled  [ =1.5.1 ]
#  3  nginx1.12   disabled  [ =1.12.2 ]
#  4  postgresql9.6   disabled  [ =9.6.6 ]
#  5  python3   disabled  [ =3.6.2 ]
#  6  redis4.0   disabled  [ =4.0.5 ]
#  7  R3.4   disabled  [ =3.4.3 ]
#  8  rust1   disabled  [ =1.22.1 ]
#  9  vim   disabled  [ =8.0 ]
# 10  golang1.9   disabled  [ =1.9.2 ]
# 11  ruby2.4   disabled  [ =2.4.2 ]
# 12  nano   disabled  [ =2.9.1 ]
# 13  php7.2=latest  enabled  [ =7.2.0 ]
# 14  lamp-mariadb10.2-php7.2   disabled  [ =10.2.10_7.2.0 ]

sudo amazon-linux-extras enable php7.2

sudo yum update
# check available php packages
yum list available '*php*'

# install desired packages (at your convenience)
sudo yum install php-json php-xml php-cli php-mbstring

It is not necessary to do all this manually if you want to host a dynamic website on AWS. There are tools to automate, like server provisioning tool Chef and Puppet. There are also PaaS that makes the process easier and simpler.

You are right, this is useful when you want to simply test or try something on AWS before using any provisioning tool.