Updating the Debian software source

1. First back up the source list and then open the source list file with Gedit or another editor:

cp/etc/apt/sources.list/etc/apt/sources.list_backupsudo gedit/etc/apt/sources.list 

2. Replace all content in sources.list with the appropriate source found, save. For example, 163 of the Debian source is:

Deb http://Mirrors.163.com/debian Squeeze main Non-free contribDeb http://Mirrors.163.com/debian squeeze-proposed-updates main contrib non-freeDEB-SRC http://Mirrors.163.com/debian Squeeze main Non-free contribDEB-SRC http://Mirrors.163.com/debian squeeze-proposed-updates main contrib non-free
Deb http://mirrors.163.com/debian-security squeeze/updates main contrib non-freeDEB-SRC http://mirrors.163.com/debian-security squeeze/updates main contrib non-free
Deb http://Http.us.debian.org/debian Squeeze main contrib non-freeDeb http://non-us.debian.org/debian-non-us squeeze/non-us main contrib non-freeDeb http:// security.debian.org squeeze/updates main contrib non-free 

Copy and paste the above contents to replace all the contents of sources.list.
3. Update of the execution source:

sudo apt-get update

4. Then, perform a real software update:

sudo apt-get upgrade

Updating the Debian software source