If you are working in the internet with ubuntu, you may need some software to be installed before it is being used actually.
If you install ubuntu with a live CD, you will not have VLC Media player, etc.
Proxy setup needed to install/update software in ubuntu
1. proxy support for Synaptic package manager
Go to Settings-> preferences –> Network Tab, click manual proxy configuration and then set the proxy ip and port
2. proxy support for apt-get
Open the file /root/.bashrc and type the following line
If your proxy server does not have username/password combination then include the following line
(NB: .bashrc file is available for all the users of ubuntu, for example if the Linux user login name is “pradeepkumar” then there will be a .bashrc file at /home/pradeepkumar/, but setting the http_proxy in those files will be of no use, because ubuntu allows installation/upgrading of software only for super users ie root, so /root/.bashrc alone will be set with the http_proxy variable)