设置root权限密码
sudo passwd root后面用的sudo指令需要输入的密码就是这里设定的
遇到所有的“Permission denied”的问题都是没有在root模式下
换源
换国内的源能够提高我们的下载速度也能避免翻墙（如果能够翻墙的话最好），目前主要有“阿里”、“清华”和”中科大“三个源
1.阿里：
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
2.清华：
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse3.中科大：
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse对于u18使用阿里源，u20使用清华源，kali使用中科大源，试试是否还能用
首先备份原来的源：
su
mv /etc/apt/sources.list /etc/apt/sourses.list.backup新建源（注意这个操作也需要在root模式下进行）：
vi /etc/apt/sources.list
进入vim编辑器后按下键盘上的‘esc’，然后顺序按下“：”+“i”+回车进入编辑模式，调节光标到开头然后用ctrl+shift+v将复制的源粘贴好后，esc+:wq+回车保存并退出
换好后更新和升级
apt update
apt upgrade安装python
u18下无python，需要手动安装
对于pwn手来说python2绝对比python3香，因为在远程交互的时候不用考虑字节类型和字符串类型的差异，而且python3不支持一些比较老的工具包（如libcsearch）
sudo apt install python
出现这个表示python已经安装好了
安装pip
sudo apt install pip
出现这个就说明安装好了
安装pwntools
pip install pwntools
可以用这个检测一下是否安装成功
安装git
sudo apt install git
出现这个就说明安装好了
安装pwndbg
先装四个库不然会报错（主要是linux下64位和32位的环境）
sudo apt-get install libffi-dev
sudo apt-get install libssl-dev
sudo apt install libc6-dev-i386
sudo apt-get install lib32z1git指令会把github上的目标文件安装到当前所在的路径
cd Desktop
git clone https://github.com/pwndbg/pwndbg
cd pwndbg
./setup.sh
cd ..（ps：安装过程中会下载所需的依赖，比较吃网络环境，如果不成功可以多试几次）
装好后的效果：
安装ROPgadget
sudo apt-get install python-capstone
git clone https://github.com/JonathanSalwan/ROPgadget.git
cd ROPgadget
sudo -H python3 setup.py install对于使用kali的师傅，装capstone这步可能有问题：
那么先用git下载下来然后make安装
git clone https://github.com/aquynh/capstone
cd capstone
make
make install安装完成后直接使用貌似会报错（如果没有请跳过）
需要用如下命令：
sudo cp -r scripts /usr/local/lib/python3.6/dist-packages/ROPGadget-6.7.dist-info注意，后面的地址不一定，是上面那张图”at”后面的地址
然后成功：
安装one_gadget
sudo apt-get install ruby ruby-dev
sudo gem install one_gadget安装成功：
安装patchelf
sudo apt-get install autoconf automake libtool
git clone https://github.com/NixOS/patchelf.git
cd patchelf
./bootstrap.sh
./configure
make
make check
sudo make install安装成功：
安装ropper
拖到虚拟机中，然后用：
tar -zxvf 压缩文件名.tar.gz解压完成后：
su
cd ropper-1.11.2
python setup.py install
cd ..安装成功：
参考文章
Linux如何进入root权限-linux运维-PHP中文网
Ubuntu18.04更换国内源（阿里，网易，中科大，清华等源） – unionline – 博客园 (cnblogs.com)