Install & create QR code.

QR code stands for Quick Response code which is a 2D bar code, readable by dedicated QR barcode readers and camera phones. The code consists of black modules arranged in a square pattern on a white background.
The information encoded can be text, URL or other data. Read more here.

QR codes can be created in Linux using Qrencode.

Installing steps for Ubuntu:

#sudo apt-get install qrencode

You can use dpkg to know more about qrencode after installing it

#dpkg -s qrencode

Installing steps for RedHat/Fedora Linux:

#yum install qrencode

Check details of the package.

#yum info qrencode

You can also download qrencode from here

After installing, create QR codes through Terminal,

#qrencode -o [file.png] '[text/url/information to encode]'

Qrencode for this blog.

#qrencode -o linux-techy.png 'http://www.linux-techy.blogspot.com'

If you want to increase the size of QR code generated, use the ‘-s‘ argument where the value of ‘-s‘ will generate ‘sxs’ 2D image.

#qrencode -o ~/Desktop/google.png -s 8 'http://google.com' 

This will create 8x8 image.

References -

http://en.wikipedia.org/wiki/QR_code

http://www.linuxaria.com/pills/qr-code-in-linux?lang=en