Tag Archives: Operating system

Simple Terminal Commands to check 32/64-bit Version and Installed RAM on Ubuntu Computer


Courtesy of nixpal.com

When you want to check if you have a 32-bit or a 64-bit Linux you can open a Terminal and just type:

file /sbin/init



If you prefer to know how much about the RAM you installed on the PC, type:

free -m


grep MemTotal /proc/meminfo

for more detailed info you can try:

cat /proc/meminfo


grep MemTotal /proc/meminfo

if you prefer to monitor your RAM in real time.


Courtesy of validwebs.com

Configure OpenDNS on your Ubuntu Computer through DDclient in just 6 steps – Tutorial

1 – Why should I change DNS? 
You “use” them in any moment, every time you are in front of a computer but usually you don’t consider to directly manage or change them because you think that it is not worthy to do anything with them. 
On the contrary, you know that many different online companies offer dedicated DNS addresses you can use to substitute the default DNS addresses provided by your ISP.
So, at this point, your main question is “Why should I change DNS on my route or my computer”?
For example, for one or more of these different reasons:
– to have a chance of a possible increasing of speed and reliability when you surf Internet; 
– if you want to delegate to a third “professional” part some security tasks (e.g. third party security filtering to protect yourself against phishing or viruses);
acces websites that are normally geoblocked by commercial policies/agreements or censorship imposed by Governments;
parental monitoring if you prefer to have a rough idea of what websites your children visit or if you whant to filter some specific contenents.
2 – Choose a reliable DNS provider
If you decide that you want to try a different DNS provider you need to choose a reliable one. A quick search on Internet will help you to find the most appropriate DNS Provider for your needs.
In this specific case we are examining how to configure the DNS from OpenDNS.com so, if you want to test it, you have to sign up for a free account on opendns.com or simply copy the DNS addresses you find in the bottom right of their homepage or sign up for a OpenDNS.com free account. In the last case, you have the possibility of monitoring your traffic in a professional statistical way and probably you will satisfy one or more of the reasons that may explain your choice to use different DNS. 
3 – Install DNS from OpenDNS on your router
If you want to use OpenDNS on your LAN you have to configure the router through the its configuration interface. The way you can do this varies from one router to another but in all the popular models you will easily find a specific sub-menu where you could activate the “use predefined DNS” option compiling the two addresses provided by OpenDNS.
In this way all your LAN traffic will be pipelined through OpenDNS and you will not need to singularly configure each computer you have.

Image from: oriental-press.com

4 – Install DNS from OpenDNS on your Linux computer
4a – Preliminary configuration.
The problem with opendns.com is that it doesn’t provide an official tutorial to correctly install its DNS on a Linux machine. For this reason you can follow this brief notes that I wrote after installing it on a Ubuntu 14.04 LTS Ubuntu computer.
Go to the OpenDNS.com support page dedicated to the installation on Ubuntu and follow their instructions:
I exactly followed all the instruction till the point 8 but, when I had big problems when I typed:
sudo ifdown eth0 && sudo ifup eth0
because this message appeared:
ERROR unknown interface eth0=eth0
The matter is that my ethernet is really named eth0 (I double checked using the commands ifconfig and netstat -r -n) but it was not possible to operate on it.
To solve this problem I used the Poorak’s Blog suggestion and I had to open the interface file via Terminal with:
sudo nano /etc/network/interfaces 

– or if you prefer:

sudo gedit /etc/network/interfaces
and manually add these lines:
auto eth0
iface eth0 inet dhcp
then I restarted my networking
sudo /etc/init.d/networking restart
4b – Install DDclient on Ubuntu if you have a dynamic IP
Normally the Internet Service Provides provides a dynamic IP to users that may change over time. So, if you don’t want to pay more to obtain a static IP, you need to install a software that could constantly communicate your actual IP address to OpenDNS.com. In my case, I dedcided to install DDclient to be able to continue to properly use the OpenDNS.com services.
To install DDclient I preliminarly had to install coreutils through Terminal:
sudo apt-get install coreutils
and the required SSH and SSL sockets:
sudo apt-get install ssh libio-socket-ssl-perl
and finally the DDclient:
sudo apt-get install ddclient
At this point you manually edit the configuration file:
sudo nano /etc/ddclient.conf
(or, if you prefer sudo gedit /etc/ddclient.conf)

## OpenDNS.com account-configuration
use=web, web=myip.dnsomatic.com


– ‘opendns_network_label’ is the label given to the network you’re updating in your account.
If you have spaces in your network label, replace them with an underscore ( _ ) 
You can find the network label in the Settings Tab of the OpenDNS Dashboard.
– the login is your email address with OpenDNS
– the password is your opendns password. 
“If you have special characters in your password wrap the password in single-quotes ( ‘ ). 
If there are any single-quotes in your password, put backslash ( \ ) before the single-quote to escape the character”.
5 – Start OpenDNS and DDclient on your Ubuntu computer
At this point you have all the elements to start  so you can open a Terminal and type: 
sudo /usr/sbin/ddclient chkconfig ddclient on && sudo /usr/sbin/ddclient service start
On the other side, if you want to check the status of DDclient, you will type:
sudo /etc/init.d/ddclient status

6 – Configure Linux OS to start DDclient at boot on Ubuntu

On Ubuntu is really simple to configure DDclient to start at the computer boot. You have to open the Session and Startup manager through the desktop Dash. Now you are able to Add a specific command to the Application Autostart menu to run DDclient at the boot:
sudo /usr/sbin/ddclient chkconfig ddclient on && sudo /usr/sbin/ddclient service start
If you are configuring OpenDNS through DDclient on a different Linux distribution you can google the right tutorial or follow the guide created on aboutLinux.info.
At this point you will automatically use OpenDNS on your Ubuntu computer. 

3 things you need to remember when Upgrading to Fedora 23 as for the Unicmen’s instructions

The upgrade from Fedora 22 to Fedora 23 is not automatic, as usual in my Fedora experience, but it is really simple to manage if you follow the path suggested by Unixmen.

There are few things you need:

connect your laptop to the power plug (if you use a laptop);

– a couple of hours (something more or less depending on your CPU, RAM, Internet connection speed, etc..);

few lines of commands on the Terminal

The upgrading process is well structured and to start it you need to launch Terminal and upgrade the native Fedora Fedup with its new version that now is integrated into DNF:

dnf upgrade

Then you have to install the DNF plugin:

dnf install dnf-plugin-system-upgrade

and finally you can start the “core” part of the upgrade just typing:

dnf system-upgrade download –releasever=23 –allowerasing –best 


– allowerasing will continue the upgrade also in presence of any “old” (not yet upgraded) third part repositories that normally would have completely stopped the main upgrading process

-best is a verbose mode in case of unsatisfied dependencies

After a while, depending on your Internet connection speed, you will be able to conclude the upgrade typing:

dnf system-upgrade reboot

Your laptop will reboot and the upgrade starts.

From now you spend more than 40 minutes waiting and answering to few easy questions that the OS asks you to solve some configuration matters.

The length of the waiting time depends obviously on the CPU, the RAM and the type of Hard Disk installed into your PC.

That’s it!


Image from redpill-linpro.com

Cloning block devices online using Software RAID



Image: Jack Wallen


Ubuntu GNOME 15.10: The perfect Linux desktop distribution


TrueCrypt – Try it again! Waiting for CipherShed…

truecryptlogo_256TrueCrypt is safer than we thought! A specific audit tested TrueCrypt 7.1 unmantained through a complex verification process and the results are surprising.

First of all we have to consider that TrueCrypt is not mantained since 2014 and that its “natural” fork, VeraCrypt, is directly developed by Microsoft. For this simply reason many former TrueCrypt users prefer not to use VeraCrypt.

Secondly, the bugs revealed by the testers in TrueCrypt are less worrying than that discovered using its competitors solutions.

For this reason I decide to install TrueCrypt (that I use previously it was unmantained) on my Fedora 22 laptop.

To begin, I searched for a good repository and, at the end, I opted for that mantained by GRC. So I downloaded the TrueCrypt 7.1 archive from GRC that is still storing all the others TrueCrypt versions.

I decided to use the 7.1 version because it has more features than the last 7.2 version (the last known release of TrueCrypt). In any case I am monitoring the Swiss website and I wish that the CypherShed project will be completely developed soon.

After I extracted the file and moved it to a specific folder.

Last but not least I opened Terminal and typed:

sudo ./truecrypt-7.1a-setup-x64

and the software was correctly installed into my Fedora 22 OS.

After some tests I can adfirm that TrueCrypt is still a good security solution not only for the above mentioned audit but also because it is really stable, flexible, full of useful features and simple to use.

To sum up: Try it… again!

Update from Fedora 18 to 20 or 21 in few simple clicks and without (I hope) problems!

Fedora 21Sometimes simple things become hard problems. This happened to me when I discovered that my Fedora 18 OS was obsolete (very old indeed) and I tried to upgrade it to the Fedora 20 version.

Fedora 18 doesn’t support the automatic OS upgrade so I had to spend some hours to find information on Internet and create the right DIY solution for my case. At the end of my little (sic!) research I discovered that I was able not only able to upgrade the PC to Fedora 20 but I also found a good “trick” to upgrade to the latest Fedora 21 following in just a couple of steps with the help of fedup and some other escamotages.

This is how I succeed…

First, you have to open a Terminal and type:

init 3

but you will immediately leave the Fedora GUI and so it’s better if you write the below commands on an -old style, paper notepad- to be sure to have all the right information in you hands and correctly manage the upgrade from Fedora 18 to Fedora 20

sudo su -
yum update
yum install fedup
fedup-cli --network 20 --nogpgcheck

It’s better to add –nogpgcheck because often you are not able to complete your upgrade for the “old”, “bad saved” gpg key in your system.


Now, at the boot-up menu (GRUB 2 menu) you have to choose “System Upgrade (Fedup)”.

Then just to be sure you really have an up to date OS, in Terminal, type:

Yum update

If you have problems with one or more of your “old” repositories don’t forget to deconfigure them. In my case I had to launch this command line in Terminal due to skip an old repository and proceed with the upgrade:

yum-config-manager --save --setopt=home_moritzmolch_gencfsm.skip_if_unavailable=true

At this point, to upgrade from Fedora 20 to Fedora 21 you have to open (again) the Terminal and type:

fedup --network 21 --product=workstation --nogpgcheck


fedup --network 21 --product=server --nogpgcheck

(if your Fedora version is the server one)


fedup --network 21 --product=cloud --nogpgcheck

(for the Fedora cloud edition for generic virtual machines or Container)

Take it easy and go to bed for a long snap because, in my case, the download took some hours as for 2,577 files to be upgraded…

At the end, as before, you have to Reboot and select “System Upgrade (Fedup)” at the boot-up menu (GRUB 2 menu) and all the necessary files will be installed. Again, take a good book to read while you wait the installation.

Good luck and remind you MUST backup all your data before you start any upgrade because unforeseen risks are always around the corner!