工作日の印象 002

## check who is using 'apt'
## -i ignores uppercase/lowercase
ps aux | grep -i apt
  
## you find apt.systemd.daily update, 这是一个后台自动运行的系统更新的守护进程
sudo kill $pid
  
## check again by "ps aux | grep -i apt", if not, force to kill it
sudo kill -9 pid

## 备份源列表
cp /etc/apt/sources.list /etc/apt/sources.list.bak
  
## 使用清华源覆盖或者置顶（推荐覆盖如果有其他源的报错）
## https://mirror.tuna.tsinghua.edu.cn/help/ubuntu/
sudo vim /etc/apt/sources.list
---
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-security main restricted universe multiverse
  
# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ xenial-proposed main restricted universe multiverse
---
  
## update index
sudo apt update

## -v, verbose, 打印拷贝文件过程
cp -v a b
  
## -r 递归复制目录到目标位置下,若目标不存在则类似复制为目标
cp -r dir1 dir2