Credit Card numbers or IMEI in Java (Luhn Algorithm)

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Credit Card, Credit Card Number, Hans Peter Luhn, IMEI number, Java Luhn, Java Luhn Implementation, Luhn, Luhn Algorithm, Test Credit Card, Test IMEI

Some people ask me about how banks or online retailer know when their credit card number is wrong without a regular request or how their mobile services provider or mobile apps know their smartphone or tablet identification(IMEI) are invalid due to initial system configuration manipulation.

What if I tell you the similarity between this identifications and the java code behind the scene?

It sounds really cool, yeah?

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Open Terminal in Nautilus

Ubuntu is very cool but in order to be great to programmers and OS administrators I thing it will helpful to add “Open terminal here” option to Nautilus context by right-clicking menu.
The additional benefit over Ctrl+Alt+T shortcut will be a fast way to locate the new terminal prompt in the context of open Nautilus window.

Procedure:
1. Install nautilus-open-terminal package
2. Restart Nautilus

To do this, Open terminal and run:

sudo apt-get install nautilus-open-terminal
nautilus -q

Now you can be able to see “Open in terminal” option on right-clicking.

Note: In Ubuntu 16.04 LTS, this procedure isn’t necessary because Canonical finally include this functionality to the default distro.

Enjoy !.

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How can I remove old kernels/install new ones when /boot is full?

Some time ago the Ubuntu 14.04 LTS Software Updater show me this error “Not enough free disk space. The upgrade needs a total of 93.1 M free space on disk ‘/boot’. Please free at least an additional 5,664 k of disk space on ‘/boot’.”

I find it strange that Canonical has removed the solution message of the original text, moreover, when I was searching the command to clean /boot (I had forgotten :-D) I found some caveman procedures, therefore, I going to show you the easy way to remove old kernels to install new ones when /boot is full.

Create a directory if doesn’t exist

If you have to create a directory if doesn’t exist, you can use this code:

Defensive programming

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Defensive programming

I think that one of best coding practices I have learned over time which can help improve the quality of software is the defensive programming; consequently, I share this link with you in order to explain what I’m refer to.

Go to Bolivartech article: Defensive programming to mitigate security breach and unforeseen events

Video: What’s a computer programmer ?

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Bill Gates, computer program, Mark Zuckerberg, Programmer, Steve Jobs

I love this video!!!
It’s a short and beautiful presentation about what’s a computer programmer with short interviews with some personalities like Bill Gates, Mark Zuckerberg, Steve Jobs, etc. What although perhaps you are a programmer I recommend you to see it.

Enjoy!!!

Hackers against Islamic State?

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anonymous war, ISIS, Paris attacks

Regarding the latest attacks by ISIS in Paris, I think this article is very interesting for my readers who are thinking how dangerous is the presence of terrorist groups on the Internet and the answers of another potentially dangerous groups like hackers.

Go to Bolivartech article: Hackers can be a Threat to Islamic State?

How to Install Oracle Java 8 or 7 in Ubuntu

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oracle java ubuntu install

In some situations you need to run applications developed in Oracle Java over Ubuntu.
If you try to do this with recommended open souce flavors like openjdk-8-jdk and/or openjdk-8-jre sometimes rise up errors or malfunctions.

You can correct this situations by installing original Oracle Java Version 7 or 8 doing this procedure in a terminal:

Bitcoin developer nominated to Nobel Prize in economics

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Bitcoin, Novel, Satoshi Nakamoto

The mysterious creator of the Bitcoin cryptocurrency Satoshi Nakamoto, has been nominated for the Nobel Prize in Economics by the Professor of Finance PhD Bhagwan Chowdhry, University of California (UCLA). The big problem is that nobody knows their identity.

Ubuntu: How to set a keyboard shortcut for System Monitor

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kill process, monitor, shortcut, system, ubuntu

GNOME System Monitor

I love Ubuntu but I felt frustrated with the fact it doesn’t have a shortcut to open the GNOME System Monitor like you can do on Windows with CRTL + SHIFT + ESCAPE shotcut to open System Monitor, this is especially good when you have programs like Chrome who likes to consume memory so fast and some times it freeze and you want to kill its processes.

Don’t misunderstand me, I don’t like Windows but actually some little things are more practical.
I going to show you some alternatives: