Homebrew 卸載時出現：Failed to locate Homebrew! 錯誤

今天在 MacBook 上安裝 Homebrew，結果中間斷了網，想從新卸載重裝，結果一直卸載失敗。問題現象以下：

問題現象

卸載時錯誤以下：

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
Failed to locate Homebrew!

重裝時錯誤以下：

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
It appears Homebrew is already installed. If your intent is to reinstall you
should do the following before running this installer again:
    ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
The current contents of /usr/local are bin Cellar etc Frameworks Homebrew include lib opt sbin share var

問題分析

google 後發現有這樣的問題討論帖子，有人建議執行：

rm -rf /usr/local/.git

後再從新安裝。貌似這個解決方案有不少人成功了。不過我這麼作後仍是出現卸載失敗。

粗粗想了一下，大概由於是斷網形成的，斷網致使了安裝不徹底，在安裝目錄產生了一些不完整的目錄文件。
查找了一下，找到一個目錄
執行：

mdfind homebrew

找到：

/usr/local/Homebrew

cd 到/usr/local/目錄，ls -al 了一下，發現還存在幾個安裝時出現過的目錄名字，因而一併刪除了。

下面是當初安裝時的提示信息：

➜  local ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
==> This script will install:
/usr/local/bin/brew
/usr/local/share/doc/homebrew
/usr/local/share/man/man1/brew.1
/usr/local/share/zsh/site-functions/_brew
/usr/local/etc/bash_completion.d/brew
/usr/local/Homebrew
==> The following new directories will be created:
/usr/local/Cellar
/usr/local/Homebrew
/usr/local/Frameworks

Press RETURN to continue or any other key to abort

下面是 ls -al 的信息:

➜  local ls -al
total 0
drwxr-xr-x  13 Ade   wheel  442  9 12 19:15 .
drwxr-xr-x@ 12 root  wheel  408 12  5  2015 ..
drwxrwxr-x   2 Ade   admin   68  9 12 19:15 Cellar
drwxrwxr-x   2 Ade   admin   68  9 12 19:15 Frameworks
drwxrwxr-x   3 Ade   admin  102  9 12 19:15 Homebrew

問題解決

刪除 Homebrew 安裝時產生的目錄

rm -rf Cellar Frameworks Homebrew

從新執行安裝命令：

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

按照提示 回車 繼續執行，
最後出現下面的提示表示安裝成功

==> Installation successful!
==> Next steps
Run `brew help` to get started
Further documentation: https://git.io/brew-docs
==> Homebrew has enabled anonymous aggregate user behaviour analytics
Read the analytics documentation (and how to opt-out) here:
  https://git.io/brew-analytics

執行 brew help，正常顯示命令幫助，Nice ！