vi /etc/apt/sources.list

原有的先注释，改为阿里的。

deb http://mirrors.aliyun.com/raspbian/raspbian/ buster main non-free contrib rpi
deb-src http://mirrors.aliyun.com/raspbian/raspbian/ buster main non-free contrib rpi

install pip-autoremove

pip install pip-autoremove

remove "somepackage" and it's dependencies:

pip-autoremove somepackage -y

git clone的时候，填错密码，再次git clone也不会提示输密码，表现如下

$ git clone https://wwww.git www
Cloning into 'www'...
remote: Coding 提示: Authentication failed.
remote: 认证失败，请确认您输入了正确的账号密码。
fatal: Authentication failed for 'https://wwww.git/

原因是 windows将密码信息保存在本地。需要这样处理
Control Panel\All Control Panel Items\Credential Manager
即 控制面板 > 用户账户 > 管理你的凭据 > Windows凭据
在Windows Credentials中找到git地址，编辑密码即可。

1 check the latest docker-compose version
https://github.com/docker/compose/releases

2 run the command

curl -L https://github.com/docker/compose/releases/download/1.25.0/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose
chmod +x /usr/local/bin/docker-compose
ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose

3 here we go.
docker-compose --version

if [ -z ${var+x} ]; then 
    echo "var is unset"; 
else 
    echo "var is set to '$var'"; 
fi

var is the variable name,

To check for non-null/non-zero string variable, i.e. if set, use
if [ -n "$1" ]

if [ -n "$1" ]; then
    echo "You supplied the first parameter!"
else
    echo "First parameter not supplied."
fi

https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash