How to add Debian software repository

Software repository does not add when we install Debian Linux from CD/DVD without Internet connection. You can't update the Debian Linux without software repository. But you can add software repository later. Find a repository near your area. Download from remote server take long time to download updates.

You can find Debian software repository near your area by visiting Debian Source List Generator. 

In my experience, repositories from India is slow and so I make use Debian repositories from Japan. 

Add repository address to Debian

Open Applications > Accessories > Terminal 

Open sources file and add repository address.

su

leafpad /etc/apt/sources.list

Copy paste the lines to the file. Here is the repository from Japan,

deb http://ftp.jp.debian.org/debian/ wheezy main
deb-src http://ftp.jp.debian.org/debian/ wheezy main

deb http://security.debian.org/ wheezy/updates main
deb-src http://security.debian.org/ wheezy/updates main

# wheezy-updates, previously known as 'volatile'
deb http://ftp.jp.debian.org/debian/ wheezy-updates main
deb-src http://ftp.jp.debian.org/debian/ wheezy-updates main

Save and close the file. Update the sources list.

apt-get update