Installing loopback interfaces in Ubuntu

Note: Run all commands as root

apt-get install uml-utilities
modprobe tun


Running this command will install tap0, tap1 and so on..


tunctl 

To configure the loopback ip address/mask:

for tap0:
ifconfig tap0 (ip-address) netmask (mask) up

to test run ifconfig

To remove the configured ip addresses:

ip addr flush tap0


To remove the loopback interfaces:

tunctl -d tap#

How to setup a PDF Printer in Xubuntu

From Ubuntu Software Center, search for preferred PDF printer application. 

I have installed Master PDF Editor (free) Ubuntu.com user login required.

Install Cups PDF package: 

apt-get install cups-pdf

Go to System-----> Administration ----> Printing.

A pdf printer should be available. Try to print any documents and check 

the print out under /home/login-name/PDF/