Excellent guide to install MariaDB/MySQL on top of CentOS 7 or AWS Linux 2

Here's the URL to it:
https://computingforgeeks.com/how-to-install-mariadb-on-centos/

Fix blank empty page for PHP page

I'm getting a blank pahe for my 7.3 PHP page on top of Apache 2.4 and AWS Linux 2 OS:

<?
phpinfo();
echo "test";
?>

What I'm doing wrong? Well, it's just a php missing as per below:

<?php
phpinfo();
echo "test";
?>

After this addition, it works like a charm.

Install PHP 7.3 on Amazon AWS Linux 2 instance

Following scenario is outlined below: First will install default PHP that comes with AWS Linux 2 (5.x) then will install by mistake 7.2 and after properly install 7.3. All steps are done using sudo root privilegies:

1. Check the following command to see available php packages available and versions:
yum list available php\*

2. Install PHP:
yum install php

3. Using the below command check installed version of PHP - it shall default to 5.x:
php -v

4. Install php 7.2 using amazon-linux-extras:
amazon-linux-extras install php7.2

5. Now you get proper version:
php -v


6. But wait, you want to install latest version (7.3), how do you do that? It shows enabled only 7.2:
amazon-linux-extras list

7. First, disable 7.2 version:
amazon-linux-extras disable php7.2

8. Enable 7.3:
amazon-linux-extras enable php7.3

9. Install PHP, it shall install 7.3:
yum install php


10. Check version:
php -v

PHP 7.3.11 (cli) (built: Oct 31 2019 19:16:47) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.3.11, Copyright (c) 1998-2018 Zend Technologies

Good Job! You are now using the latest and greatest PHP.

Install httpd webserver on Linux RedHat, CentOS or AWS Linux instance

1. Install HTTPD on AWS Linux:
sudo yum -y install httpd

2. Start HTTPD service:
sudo service httpd start

3. Check status:
sudo service httpd status
Active: active (running) since Wed 2019-12-25 23:27:19 UTC; 1s ago

4. Default webfolder is under:
cd /var/www/html

5. Create a sample hmtl file:
touch index.html

vi index.html
Add Test:
Hello dtechie!

Save.

5. Under AWS Security Group, add the following inbound rule:










6. Test by navigating to instance public IP/DNS: 

Regular Linux yum update

1. Check your latest patches status:

sudo su 

yum check-update

2. Update all definitions to latest versions:

yum update 

Amazon AWS Linux - Enable password authentification only for certain user

1. Add new user part of sudoers:
sudo su
useradd dtech

2. Create password:
passwd dtech
 
3. Make sure it has sudo rights:
cd /etc/sudoers.d/
touch dtech_other_sudoers
chmod 440 dtech_other_sudoers
vi dtech_other_sudoers

dtech  ALL=(ALL)       NOPASSWD: ALL

# This comment is here to have new line at end of file
4. Enable password authentification:
vi /etc/ssh/sshd_config

5. Add following lines to the very end of the file:
Match User dtech
    PasswordAuthentication yes
  
6. Restart sshd service
service sshd restart

7. Test and you shall now get password prompt only for your user:
ssh dtech@35.171.158.153
dtech@35.171.158.153's password:
Last login: Wed Dec 25 22:17:05 2019

Delete a file that begins with "-"/ hyphen, dash or minus on Linux

Use the following command:

rm --  -filename