Installing MySQL Server in Ubuntu 16.04

Server Operating System        : Ubuntu 16.04 (Xenial Xerus)

Basically, this is a post which is made to describe on how to uninstall MySQL Server installation in Ubuntu Linux distribution. I decide to uninstall MySQL server because it has already crashed. Due to the space storage which has already full caused the operation performed by MySQL service to write data has already failed. I am trying to recover it but the process itself has come to a dead end.  Instead of wasting lots of time for troubleshooting  trying to straight up MySQL Server in order to be properly functioned, I decide to uninstall it and reinstall it with a brand new one. Below is the installation process :

  1. Using apt-get command, we can remove any kinds of package which have already been installed. The execution of the command is shown below :
apt-get install mysql-server
  1. After finishing on execute the above command, we will execute another command which is shown as follows with the steps explained :

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Checking Firewall State in Linux CentOS 7

Checking Firewall State in CentOS 7

How to make sure that you have activate firewall in your CentOS 7 which is mainly your currently used operating system in either can be your PC, laptop or server ?. Firewall function which is represented by firewalld service can actually be monitored by accessing several command.  Below is the steps :

1. First of all, you have to know that you have to make sure the firewalld service has already been installed. You can read the following link to understand the steps.

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Switching User in Linux Operating System

Switching User in Linux Operating System

As multi-user operating system, many users can log in to the operating system at the same time. But not only limited to that aspect, even a user can switch to other user after that user successfully logged in to the operating system.

How can you even switch to another user after you successfully logged in to the Linux operating system ?. You can use the following command to do that :

username@hostname:~ $ su

It can be recognized which is the short abbreviation of switch user, substitute user or super user. It is actually depends on the purpose of the command’s execution.  We can describe several functions of the command as follows :

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Checking your Current User Logging in Linux

Check Your current User Identifier Information

Linux as a multi-user operating system permit several users login to the operating system at the same time. Other cool thing is it also permit someone to switch from a user to another. But how do we know or do we check currently user whom we used right now ?. Basically it can be read from the bash prompt as soon as we login to the operating system via terminal or CLI (Command Line Interface). Below is the standard format of bash prompt which is displayed normally in terminal or CLI (Command Line Interface) :

For normal user, below is how the bash prompt will be displayed as the following pattern :

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Installing Firewall Utility in CentOS 7

Installing Firewall Utility in CentOS 7

Since CentOS 7, the mechanism for filtering incoming and outgoing packet data has been replaced. The previous version of CentOS has been utilizing iptables as the default utility to perform firewall function up to CentOS 6. But since CentOS 7, the function which is previously handled by iptables has been replaced with firewalld. It is actually a dynamic daemon responsible managing firewall tasks.

But those who prefer iptables as their utilities to administer the firewall rules can still prefer this utility by installing it with yum package manager which is used in CentOS. Although iptables still can be installed by using yum utility,it is strongly suggested to migrate by using firewalld since there are highly chance that iptables itself will be discontinued. Below is the process on installing firewalld in CentOS 7 :

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Changing Java Executable Program Using alternative Command in Linux

Operating System            :  CentOS 7

Java                                  : JDK 1.8.0_91

In order for several utilities or programs to run normally some of them need to be executed on top of Java Runtime Environment. Sometime we need to install different version of Java Runtime Environment from the one which has already installed as default Java Runtime Environment in order for those utilities or programs run well.  Below is the step which has to be done :

  1. First of all, we have to install Java Runtime Environment which I preferably do that by downloading portable compressed file of Java Standard Development Kit which is provided from the official site of Java available. In the past, I usually visit Sun Microsystem’s website to look for the compatible JDK, but nowadays since the Sun Microsystem’s acquisition by Oracle has already happened, the official JDK can now be found in Oracle’s official website.  Normally, I put all utilities or program which is installed by extracting it in /opt,  so the command for installing Java Runtime Environment which also regularly come as a package with Java Development Kit.

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Checking Alfresco Version

Checking Alfresco Version

Based on the official site of Alfresco, it is said that Alfresco is a software which is intended for business software as an open platform. To check version of currently running Alfresco, we can do it by checking the log file which is produced by Alfresco itself. To check the log file, we can actually execute the following command so we can check currently running version of Alfresco :

grep –i “alfresco started” alfresco.log

Pattern :

grep [parameter] [keyword] [log file name]

Where grep is a command which is used to print lines matching a pattern specified in the parameter value.

-i is an additional parameter which is used for insensitive search.

The keyword is placed after the additional parameter given which is enclosed within double quotes. To be able to find alfresco’s version, we have to search keyword related with the start of the alfresco process. The keyword is “alfresco started” in this context is picked because it will also provide additional information of the already started alfresco process which is more specifically the version of alfresco.

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