你的osx中没有gitk？

你的osx中没有gitk？一句话：你的git版本太低了，gitk是跟随git一起安装的。

解决办法：重新使用brew安装git就好了。

先看下git版本：

andy@AndyMacBookPro:~$ git --version
git version 1.9.5 (Apple Git-50.3)

可以使用brew重新安装git：

首先升级brew：

brew update

然后安装git：

andy@AndyMacBookPro:/usr/local/webdata/chrome_ext/fanlihelper$ brew install git
==> Downloading https://homebrew.bintray.com/bottles/git-2.6.2.mavericks.bottle.tar.gz
######################################################################## 100.0%
==> Pouring git-2.6.2.mavericks.bottle.tar.gz
==> Caveats
The OS X keychain credential helper has been installed to:
  /usr/local/bin/git-credential-osxkeychain

The "contrib" directory has been installed to:
  /usr/local/share/git-core/contrib

Bash completion has been installed to:
  /usr/local/etc/bash_completion.d

zsh completion has been installed to:
  /usr/local/share/zsh/site-functions
==> Summary
/usr/local/Cellar/git/2.6.2: 1398 files, 33M

安装之后发现git版本还是没有变：

andy@AndyMacBookPro:/usr/local/webdata/chrome_ext/fanlihelper$ git --version
git version 1.9.5 (Apple Git-50.3)

我们使用which git，发现git的目录还是/usr/bin/git，按理git应该位于/usr/local/bin/git中才对，是目录在profile中没有设置好，所以我们先升级brew：

brew upate

最后发现有此提示：

Consider setting your PATH so that /usr/local/bin
occurs before /usr/bin. Here is a one-liner:
    echo 'export PATH="/usr/local/bin:$PATH"' >> ~/.bash_profile

然后我们根据提示来执行：

echo 'export PATH="/usr/local/bin:$PATH"' >> ~/.bash_profile

参考（）这里，这么说的：

If you already have git installed via homebrew, you can just do upgrade:

也就是说，刚刚我们已经brew install git过了，我们现在导入了path之后，我们可以直接：

brew upgrade git就可以了，效果如下：

$ which git
/usr/bin/git
$ brew upgrade git
$ which git
/usr/local/bin/git

之后我们看到git版本正确了：

andy@AndyMacBookPro:/usr/local/Cellar/git/2.6.2$ git version
git version 2.6.2

然后我们这时候在shell中执行gitk也可以了~~

最后我们看一下系统中的情况：

andy@AndyMacBookPro:/usr/local/Cellar/git/2.6.2$ /usr/bin/git version
git version 1.9.5 (Apple Git-50.3)
andy@AndyMacBookPro:/usr/local/Cellar/git/2.6.2$ git version
git version 2.6.2
andy@AndyMacBookPro:/usr/local/Cellar/git/2.6.2$ which git
/usr/local/bin/git
andy@AndyMacBookPro:/usr/local/Cellar/git/2.6.2$ which gitk
/usr/local/bin/gitk
andy@AndyMacBookPro:/usr/local/Cellar/git/2.6.2$

可以看到目前我们osx中有两个git，而gitk也在/usr/local/bin/ 目录下。

参考：
http://stackoverflow.com/questions/17582685/install-gitk-on-mac