Command ifconfig not found, but can be installed with: sudo apt install net-tools

原因是系统 缺少东西，需要更新

输入： sudo apt-get update

结果出现下面这个

E: 无法获得锁 /var/lib/apt/lists/lock - open (11: 资源暂时不可用)
E: 无法对目录 /var/lib/apt/lists/ 加锁
 

接着输入 sudo rm /var/lib/apt/lists/lock

输入： sudo apt-get update

安装了一堆文件

如果sudo apt-get update下载特别慢的人，可以尝试换镜像源

主目录进入 /etc/apt

复制source文件，换下镜像源，这样可以留下源文件，：sudo cp sources.list sources.list.bak

打开source文件，sudo gedit /etc/apt/sources.list

将里面的内容全选替换为

# deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted

deb-src http://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial main restricted

deb-src http://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial universe

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates universe

deb http://mirrors.aliyun.com/ubuntu/ xenial multiverse

deb http://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse

deb http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties

deb http://archive.canonical.com/ubuntu xenial partner

deb-src http://archive.canonical.com/ubuntu xenial partner

deb http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted

deb-src http://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties

deb http://mirrors.aliyun.com/ubuntu/ xenial-security universe

deb http://mirrors.aliyun.com/ubuntu/ xenial-security multiverse

现在输入sudo apt-get update就快了

下载好后在输入sudo apt-get install net-tools

再输入ifconfig就查到了ip信息