Empty Trash From Command Line In Ubuntu

CLI is such a sexy piece so why bother using GUI, even for cleaning up your trash. In this post, you will see how you can empty trash in Ubuntu from command line.

The trash you see in GUI is nothing but just the view for the files deleted by users which are temporarily moved to the special location of user's home directory. For any user, the trash location is ~/.local/share/Trash/. That is, whatever a user deletes gets saved in this location.

samar@samar-Techgaun:~$ rm -rf ~/.local/share/Trash/

I hope this becomes useful :)


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Enable Fingerprint Authentication In Ubuntu

So you got fingerprint reader in your device but have not been able to use it under ubuntu? Follow this How To to enable fingerprint authentication in ubuntu using the Fingerprint GUI from fingerprints reader integration team.

First make sure your fingerprint hardware is supported. You can check for the vendor and device ID by entering the following command:

samar@TG:~$ lsusb | grep -i finger | awk -F " " '{print $6}'
138a:0005

This link provides the list of the supported fingerprint readers.

Installation is easy. Fire up the terminal and enter the following commands:

sudo add-apt-repository ppa:fingerprint/fingerprint-gui
sudo apt-get update
sudo apt-get install libbsapi policykit-1-fingerprint-gui fingerprint-gui

You will have to restart the system or log out the session and login back to use and configure the fingerprint GUI.

Press Alt + F2 and type fingerprint-gui. From this GUI, you can configure and enroll your fingerprints.

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Add Google Search Support In Gnome-Terminal

Gnome-terminal is my favorite thing in my system and recently I came to know that I could add google search support in gnome-terminal which is totally awesome. Ubuntu Tweak already includes the google search support but if you want google search in your terminal without the whole ubuntu tweak, you can follow this guide.

All you need to do is add the PPA and you can easily install the gnome-terminal with google search support. Fire up the terminal and enter the following commands:

sudo add-apt-repository ppa:tualatrix/personal
sudo apt-get update
sudo apt-get install gnome-terminal

Credits: Ubuntu Tweak


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Pinkie Pie Wins $60K In Pwnium2

The teenage hacker who goes by the handle "Pinkie Pie" once again successfully exploited the google chrome browser in the Pwnium 2 event held in HITB2012 conference in Kuala Luampur. With the goal to reward the exceptional vulnerability researchers, Google Chromium team had started Pwnium earlier this year and this is the second installment of Pwnium.

Google software engineer Chris Evans writes in a blog post:

" We’re happy to confirm that we received a valid exploit from returning pwner, Pinkie Pie. This pwn relies on a WebKit Scalable Vector Graphics (SVG) compromise to exploit the renderer process and a second bug in the IPC layer to escape the Chrome sandbox. Since this exploit depends entirely on bugs within Chrome to achieve code execution, it qualifies for our highest award level as a “full Chrome exploit,” a $60,000 prize and free Chromebook. "

Chromium team has already released the patched and updated google chrome in less than 10 hours after the exploit was confirmed. The Stable channel has been updated to 22.0.1229.94 for Windows, Mac, and Linux which contains the fix for the security exploit discovered by Pinkie Pie


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Keccak Wins The SHA-3 Competition

After five years of competition, National Institute of Standards and Technology (NIST) has announced the winner of SHA-3 competition. The Keccak has been selected as the standard for SHA-3 algorithm among the 64 entries made for SHA-3 cryptographic algorithm announced by NIST back in November 2, 2007.

After three rounds of competitions, the finalists were five hash algorithms. On December 9, 2010, NIST announced five third-round candidates – BLAKE, Grøstl, JH, Keccak and Skein, to enter the final round of the competition. And, the winner is Keccak.

Keccak was designed by a team of cryptographers from Belgium and Italy, they are:

• Guido Bertoni (Italy) of STMicroelectronics,
• Joan Daemen (Belgium) of STMicroelectronics,
• Michaël Peeters (Belgium) of NXP Semiconductors,
• Gilles Van Assche (Belgium) of STMicroelectronics.

The NIST team praised the Keccak algorithm for its many admirable qualities, including its elegant design and its ability to run well on many different computing devices. The clarity of Keccak’s construction lends itself to easy analysis, and Keccak has higher performance in hardware implementations than SHA-2 or any of the other finalists.

“Keccak has the added advantage of not being vulnerable in the same ways SHA-2 might be,” says NIST computer security expert Tim Polk. “An attack that could work on SHA-2 most likely would not work on Keccak because the two algorithms are designed so differently.”

Though SHA-2 is still considered to be still secure enough for general usage, SHA-3 is thought to provide a new security tool for system and protocol designers, and that may create opportunities for security in networks that did not exist before.

If you are interested in quick summary about the pseudocode of Keccak, you can read the summary of Keccak.


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Binary, Hex, Octal and Decimal Conversion Under Linux

Base conversions are easy with linux CLI. No need of fancy GUI-based calculator to perform base conversions when there is our favorite linux terminal.

We will be using bc, a calculator language that supports arbitrary precision numbers with interactive execution of statements. We will exploit the pipelining feature of shell and will let the bc process our query to convert the numbers from one base to other.

From binary to decimal

The syntax is obvious and we will follow the similar syntax for all the conversions. In this first example, we are converting the binary number 1101101 from input base binary to decimal(obase defaults to decimal unless specified).

samar@samar-Techgaun:~$ echo "ibase=2;1101101" | bc
109

From octal to decimal

samar@samar-Techgaun:~$ echo "ibase=8;1101101" | bc
295489

From Hexadecimal to decimal

samar@samar-Techgaun:~$ echo "ibase=16;A1F3DF" | bc
10613727

From N-base to decimal

All you need to do is provide the appropriate ibase value (eg. ibase=4 for 4-base to decimal conversion).

samar@samar-Techgaun:~$ echo "ibase=16;A1F3DF" | bc
10613727

As seen in all the examples above, the conversion to decimal numbers does not require you to specify the obase as obase defaults to decimal. The same thing applies for ibase i.e. ibase defaults to decimal base by default as seen in the examples below.

Now lets try some conversion with decimal numbers as the input base.

From decimal to binary

samar@samar-Techgaun:~$ echo "obase=2;109" | bc
1101101

From decimal to octal

samar@samar-Techgaun:~$ echo "obase=8;295489" | bc
1101101

From decimal to hexadecimal

samar@samar-Techgaun:~$ echo "obase=16;10613727" | bc
A1F3DF

From decimal to N-base

All you need to do is provide the appropriate obase value (eg. obase=4 for decimal to 4-base conversion).

samar@samar-Techgaun:~$ echo "obase=4;121" | bc
1321

Below are few more examples of base conversions to clarify the use of the command.

From binary to octal

samar@samar-Techgaun:~$ echo "ibase=2;obase=8;1111" | bc
17

From hexadecimal to binary

samar@samar-Techgaun:~$ echo "ibase=16;obase=2;AFBE" | bc
1010111110111110

I hope this is helpful ;-)


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Mozilla Announces First Beta Release Of Persona

Persona is finally ready for use. Today, Mozilla is going to announce the first public beta release of Persona, a login management system that eliminates per-site passwords in websites while being safe, secure and easy to use. Mozilla Persona is a completely decentralized and secure authentication system for the web based on the open BrowserID protocol. To get started with Mozilla Persona, you'll have to signup here. FYI, Persona was first introduced as BrowserID.

Persona is now ready to use for authentication and will be available from today to the public as the first beta release. It works in all major smartphone, tablet, and desktop browsers and the user experience has been thoroughly reviewed and polished.

Available in more than 25 languages, Persona does not need any API keys and it will always remain free. Persona is an open source project and you can easily use persona with your site. Persona is safe, secure, and built on top of public key cryptography. Instead of a password, the user's browser generates a cryptographic "identity assertion" that expires after a few minutes and is only valid on a single site. Because there are no site-specific passwords, websites using Persona don't have to worry about securely storing or potentially losing a password database.

The sites such as OpenPhoto and Times Crossword are already using Mozilla Persona in their websites.

Persona is built upon BrowserID protocol. Once popular browser vendors implement BrowserID, they will no longer need to rely on Mozilla to log in. You can easily integrate Persona in few minutes. Persona is already getting integrated in different applications.

Lets see how successful will be Mozilla Persona, its success depends upon the adoption by websites and applications and then the subsequent use by the users.

Want to read more?

Announcing the Beta release of Persona

Mozilla Persona Documentation

New API for Persona


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Ubuntu 12.10 Beta 2 Released

The ubuntu developers have just released the Beta 2 of Ubuntu 12.10 Quantal Quetzal which gives the preview of the next version of ubuntu. The final ubuntu 12.10 release is scheduled for 18^th October this year. The Beta 2 release is intended to give the preview of how the final release of Quantal Quetzal will be like. The previous beta 1 release was released on 6^th September.

As always, Ubuntu has chosen the Quetzal as codename for Ubuntu 12.10. According to Wikipedia, Quetzals are strikingly colored birds in the trogon family. They are found in forests and woodlands, especially in humid highlands, with the five species from the genus Pharomachrus being exclusively Neotropical, while the single Euptilotis species is almost entirely restricted to western Mexico.

Like we heard earlier, Ubuntu 12.10 releases are no longer available as Live CD.

Download Quantal Quetzal 12.10 Beta 2 Release


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