使用 brew update 指令
# 报错
Error: The following directories are not writable by your user:
/usr/local/sbin
/usr/local/share/man/man5
/usr/local/share/man/man7
解决办法：
```javascript
sudo chown -R $(whoami) /usr/local/*
```
重新调用即可：
```
brew update
```
mac 使用 homebrew.md
Copyright: 采用 知识共享署名4.0 国际许可协议进行许可
