Author Archives: Darren

Top Five MySQL Commands

As Sys admins we are often tasks with working on multiple and disparate systems we need to know a little about everything to allow use to do our jobs effectively. This post will detail my top five MySQL commands to know – with one bonus command! The commands are:

Create database wordpress;
1. This command creates a database call wordpress.
Show databases;
1. The Command shows all databases that reside on the server.
Use wordpress;
1. Selects the wordpress database for use – all subsequent commands will run the wordpress database.
show tables;
1. Shows all tables within the current selected database.
select * from courses;
1. Displays all information from the courses table.
Bonus Command! grant all on WordPress.* to ‘wordpressuser’@’localhost’ identified by ‘wordpresspass’;
1. Grants all permissions on the WordPress database from the user wordpressuser from the local machine with the password wordpresspass

If you want to see these commands in action check out the youtube video here:

Also be sure to download the cheetsheet here which you can save and print out:

How to Install Ubuntu on AWS

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This Ubuntu Linux AWS tutorial will show you how to install Ubuntu on AWS. First you will open EC2 and search for the Ubuntu AMI. You will then step through the wizard to configure connectivity options ensuring that the Ubuntu server has a public IP allowing you to access. You will then generate a key to access your server. Next you will convert that key from pem to ppk using puttygen. Finally you will connect to your Ubuntu instance on AWS using putty Putty & Puttygen are available from:

https://putty.org

If you found this tutorial useful please consider supporting on patreon:

https://www.patreon.com/darrenstechtutorials

How to learn CentOS

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Recently on YouTube I was asked to put together some of the best resources for learning CentOS.

I’ve gathered my top 5 resources below:

How To Forge https://www.howtoforge.com/tutorials/centos/
- Some really good tutorials on this site and easy to follow
Digital Ocean https://www.digitalocean.com/community/tags/centos?primary_filter=newest
- I use Digital Ocean to host servers and theior CentOs tutorials are great some are a little old but still of a very high quality
Shameless self plug Darren’s Tech Tutorials https://www.youtube.com/darrenstechtutorials
- Tonnes of CentOs Videos aswell as plenty on windows and AWS
The CentOs wiki https://wiki.centos.org/
- Has tonnes of Great information on Centos
Last but not least the official CentOS man pages are a wealth of good information.

The Video below shows me discussing these options

How to set up a billing alarm on AWS

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The video will show you how to set up a billing alert on AWS. We will do this by setting the alarm in AWS CloudWatch. To begin you will need to:

log into your AWS account.
Next you will need to navigate to the N Virginia region.
Once in the region you can open Cloud watch t
Then Click on billing
Click create alarm
Select metric
Select USD
Enter the value you want, in our case 100 USD
Click create a new topic and enter you email
Be sure to verify your email
Click next
Give your alarm a name and click next
Click create alarm.

A full video tutorial can be seen here:

Mariadb server installation CentOS 8

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This video will show you how to install MariaDB Server on CentOS 8.

MariaDB is a free and opensource database engine.

The commands that you need to follow this tutorial are:

sudo yum install mariadb
sudo yum install mariadb-server
sudo systemctl status mariadb
sudo systemctl start mariadb

How to install Virtual box Guest additions on CentOs 8, ake CentOS 8 full screen in Virtual box

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This virtualbox tutorial will show you how to install Virtual box Guest additions on CentOs 8.

When this process is done you will be able to make CentOS 8 full screen in Virtual box, so in affect the video shows how to make Centos 8 full screen in Virtual box.

The command that i run to download the relevant packages are:

sudo yum install tar bzip2 kernel-headers perl gcc make elfutils-libelf-devel

Solved: UnCaught Error Call to undefined json decode

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This Video will show you how to resolve the error: UnCaught Error Call to undefined json_decode

I got this issue while installing moodle on CentOS 8.

To bypass this error I ran;

sudo yum install php_json

How to use snapshots on Virtualbox

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This Virtualbox tutorial will show you how to take a snapshot on Virtualbox. First you will see how to take a snapshot of a running virtual machine. You will then see how to restore the snapshot. Snapshots allow you to save the state of a virtual machine; this can be useful when you want to test something, or you’re about to make a change to that virtual machine, and you need to be able to roll back to a working instance. Snapshots have saved me on numerous occasions and are an excellent feature!