A ‘QR’ (short for Quick Response) code is a so-called ‘two-dimensional barcode’ made up from black squares on a white background. QR Codes are usually contains URLs, Text or something like ID of Product, the QR Code technology is widely use in Android and Blackberry mobile phone, if you are Blackberry or Android user i think you must be familliar with this. The image bellow is some example of QR Code.
The QR Codes
There are many resources which can help you to generate a QR Code, in Ubuntu you can use application called 'qrencode', the qrencode could help you to generate your own QR Code complete with what size do you like (Large, Medium, or Small), a manual how to use a qrencode can completely find in here. Anoher way, you can visit this website (http://qrcode.kaywa.com/) to generate your own QR Code.

This article will discuss how to read a QR Code in Ubuntu, to read a QR Code in ubuntu we need library (program) named libdecodeqr-simpletest - libdecodeqr library's simple test program, this  sample program can recognize the image file of the QR code of JIS X 0510 and ISO/IEC18004. Before we start, you should Install libdecodeqr-examples using apt-get or Synaptics Package Manager. 

  • apt-get install libdecodeqr-examples
libdecodeqr-simpletest is command based application program which is accessible through ubuntu terminal, all command and output of this application is displayed through the screen of terminal, use libdecodeqr-simpletest by using structure above :
  • libdecodeqr-simpletest <the path of QR Code image>
For more detail see the example bellow (you must have QR Codes to be testing if you don't have any please download here) :
  • libdecodeqr-simpletest /home/white/qrcode.png
the line command above is illustrated of 'reading the QR Code on the image of qrcode.png', the command above will give output on the terminal like this :
    root@ubuntubuzz:/home/white# libdecodeqr-simpletest /home/white/qrcode.png
    libdecodeqr version 0.9.3 ($Rev: 42 $)

    Hit any key to end.
The bold line above is 'exactly' the content of QR Codes inside of qrcode.png.