cygwin下git图形界面gitk和git gui安装

     在终端输入gitk后出现错误：

      Application initialization failed: no display name and no $DISPLAY environment variable

    解决方案：http://stackoverflow.com/questions/9393462/cannot-launch-git-gui-using-cygwin-on-windows

    

As of a recent Tcl/Tk update, Cygwin now uses X11 instead of GDI. In short, this means you need to install some of the Cygwin X11 packages and set them up to be able to open the GUI.

This should get you back up and running:

1. Run the Cygwin installer again (download setup.exe again if you need to).
2. At the package list, select to install "xinit" and "X-start-menu-icons"; both are under the X11 category. Click next, accept all the dependencies, and install.
3. In the Windows Start menu, you should have a new group: Cygwin-X. From there, run XWin Server.
4. In your Cygwin shell, run export DISPLAY=:0.0.

You'll need to repeat step 3 every time you reboot your computer, and step 4 every time you open a new Cygwin shell (or just runecho "export DISPLAY=:0.0" >>~/.profile to have it run automatically whenever you create a new shell).

For the interested, the reason the X11 packages aren't installed automatically is that they'renot technically needed: it's possible through somewhat convoluted means to use a different X11 server than the one Cygwin installs when you install the "xinit" package