我是个小白，在网上看文章说需要换源，我不明白什么意思？能请大神给解释一下，和告诉我怎么换源。谢谢大神了

1.打开命令行
2.$ su root
passwd:输入密码
转到超级管理员用户
3.$ leafpad /etc/apt/sources.list
跳出窗口，将下面代码替换原文：
##中科大软件源
deb http://mirrors.ustc.edu.cn/kali-security kali/updates main contrib non-free
##Bleeding Edge repositories
deb http://repo.kali.org/kali kali-bleeding-edge main
deb-src http://repo.kali.org/kali kali-bleeding-edge main
##kali国内源的地址：
deb http://ftp.sjtu.edu.cn/debian wheezy main non-free contrib
deb-src http://ftp.sjtu.edu.cn/debian wheezy main non-free contrib
deb http://ftp.sjtu.edu.cn/debian wheezy-proposed-updates main non-free contrib
deb-src http://ftp.sjtu.edu.cn/debian wheezy-proposed-updates main non-free contrib
deb http://ftp.sjtu.edu.cn/debian-security wheezy/updates main non-free contrib
deb-src http://ftp.sjtu.edu.cn/debian-security wheezy/updates main non-free contrib
deb http://mirrors.163.com/debian wheezy main non-free contrib
deb-src http://mirrors.163.com/debian wheezy main non-free contrib
deb http://mirrors.163.com/debian wheezy-proposed-updates main non-free contrib
deb-src http://mirrors.163.com/debian wheezy-proposed-updates main non-free contrib
deb-src http://mirrors.163.com/debian-security wheezy/updates main non-free contrib
deb http://mirrors.163.com/debian-security wheezy/updates main non-free contrib
保存关闭此窗口！
4.继续在命令行输入：
$ apt-get update && apt-get dist-upgrade -y
命令的作用是：更新源及更新系统软件
5.在此，就完成了换源及更新源及更新系统软件的工作啦！

请问是这样吗？我没有看到能输入密码啊？

用什么超级啊！直接从 leafpad开始