Backtrack Team: Ubuntu

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How to install CentOS in Ubuntu Virtualbox (step by step for dummies)

In this tutorial I'm going to share on how to install CentOS in Ubuntu Virtualbox. Currently CentOS 7 is the latest version in the market. This tutorial can also be used for future reference

Tutorial rundown

1)Download latest CentOS

2)Setting CentOS desired parameter in Virtualbox

3)Install CentOS

4)Restart and run CentOS from hard drive.

let's begin .

1) Download latest CentOS .

1.1) Download latest CentOS from the website.

1.2) Move the file to the location where you want virtualbox to look for.

(I prefer to keep all my image file in one folder)

2) Setting CentOS desired parameter in Virtualbox

2.1) Name the new OS and choose "Redhat" as OS version.

2.2) Set the memory size value for this Operating System.

2.3) Create a virtual hard drive.

2.4) Choose "VDI" as the hard drive file type.

2.5) Choose the file size .

2.6) Set virtualbox to use the downloaded image file. Go to "Setting>system" and look for the CentOS image file.

3) Install CentOS

3.1) Run CentOS in the Virtualbox

3.2) Since CentOS Live CD doesn't support guest os version in virtualbox, you will be prompted with warning message once you are in CentOS environment . Basically, once you use mouse to click in the CentOS space, you wouldn't be able to use the mouse on your host system .To use mouse in the host, you need to press "CTRL" button on your right hand side. Please read the message for more info.

3.3) Begin CentOS installation by clicking "Install to hard drive"

3.3) Choose the language that you will use during the installation and click "continue"

3.4) Before you start with the installation, you can customize Date,Keyboard, installation destination and network host name details .

3.4.1) Date and time setting

3.4.2) Keyboard setting

3.4.3) Installation destination and location

3.4.4) Hostname

Once you done playing around customizing installation details, click

"Begin Installation"

3.5) During the installation process, you need to create root password and you can also create a user.

3.5.1) Create root password for CentOS .

3.5.2) Create a user and it's details

3.6) Once installation finish quit the panel .

4) Restart and run CentOS from hard drive.

4.1) Power off Live Cd Centos .

4.2) Make hard disk as the first boot device for CentOS in the virtualbox.

Go to "setting>system " and drag hard disk as a first or second on the list.

4.3) Run CentOS from virtualbox. You will be using the newly installed CentOS .

Finally :)

by Malik korrich ~ mercredi 3 juin 2015 0 commentaires

Linux Bash Shell Tutorial : How to use I/O redirection.5 tips and tricks

Understanding Input Output or I/O redirection works in Linux helps us streamline our job better when working with the terminal. In this tutorial,I will share quick tips and tricks on how to use I/O redirection in our system.

A few terminology that will help you understand this tutorial is as below:

Standard Input -what is being type in terminal from keyboard.

Standard output -text that display in terminal on command execution

Standard error – text that display in terminal when a command runs and exit with an error

Content List

1)Redirecting standard output to a file.

2)Redirecting a file to standard input.

3) Redirecting standard error to a file.

4)Redirecting Standard output and error to one file

5) Disposing unwanted output -/dev/null (bit bucket)

1)Redirecting standard output to a file.

Use “>” operator sign to redirect and save output file in current directory .

To append/update existing file use “>>”

2)Redirecting a file to standard input.

Use “<” operator to redirect an input to the terminal

In above example, I write new content to file stdin and redirect stdin file to the terminal using "<" sign operator.

3) Redirecting standard error to a file.

Use “2>” operator sign to redirect standard error to a new file in current directory.

To append/update existing file use “2>>”

4)Redirecting Standard output and error to one file

Use “&>” operator sign to redirect standard output and standard error to a new file in current directory .

To append/update existing file use “&>>”

file stdouterr

5) Disposing unwanted output -/dev/null (bit bucket)

Use “2> /dev/null” operator sign to redirect unwanted output to bit bucket. Data that are redirect to bit bucket will be deleted without a trace. As such some people also call bit bucket as a black hole.

*NOTE:If you execute the same command using ">" ,"<" ,"2>" ,"&>" to same file name but with different content, the file will be overwritten with new file content .

by Malik korrich ~ vendredi 8 mai 2015 0 commentaires

Linux Bash Shell Tutorial : How to change user terminal password in Ubuntu using command line and GUI

Changing terminal password is an important part in managing a Linux system. There will be a time when you want to change terminal password to something more secure or reliable. This tutorial will guide you on how to change user terminal password using either the terminal command or Ubuntu GUI.

1)Change password from the Terminal

1.1) Run in terminal "passwd" command

orca@Positive-Space:~$ passwd

On running the command, you will be prompted to enter your new password. Enter your new password to confirm. Your password will be updated straight away .

2)Change password from Ubuntu GUI

2.1) Search user accounts from Ubuntu dash panel

Search for User accounts setting panel .

2.2)Click password panel to change the password.

2.3)Change your password and click "Change"

Logout from the system and test your new password !! :-)

by Malik korrich ~ jeudi 7 mai 2015 0 commentaires

How to delete old kernels in Ubuntu using Ubuntu tweak GUI

Kernel is an important part of Linux system. When you upgrade to new kernel version, the old kernel will be left in your system . As time goes by, this might consume your hard drive and cause problem to your system.

One of the examples that old kernel might do to your system is the system unable to install update from Ubuntu Software updater. When you click "Install Now" button, an error will occur .

"The upgrade needs a total of 79.0M free space on disk '/boot'. Please free at least an additional 7,381k of disk space on '/boot' .Empty your trash and remove temporary packages of former installation using 'sudo apt-get clean' "

One of the reasons why this problem happens is because the old kernel images are filling up your /boot drive partition .

There are few ways on how to remove old kernel. In this tutorial, I share on how to remove old kernel file images using Ubuntu Tweak program.The guide below will help you to install and delete old kernels using the program

1) Download Ubuntu Tweak program

1.1)Download Ubuntu Tweak from their website

Downloading Ubuntu Tweak

1.2)Double click the download file and finish the installation from Ubuntu Software Centre.

Ubuntu Software Centre

2)Run Ubuntu Tweak and delete old kernels

2.1)Search Ubuntu Tweak from Ubuntu dash panel and run the program.

2.2)On the Top side panel click "Janitor" and tick "Old kernel" under System.

2.3)Check your latest kernel version from the terminal by typing

orca@Positive-Space:~$ uname -r

2.4) Click the old kernel that you want to delete and click "clean" to delete old kernels. It is a good practice to keep previous latest old kernel version on your system .