Cannot launch Git GUI using Cygwin on Windows

I used to launch Git GUI within my Cygwin console without any problems, but since I updated Cygwin I've got the following error message:

$ git gui
Application initialization failed: no display name and no $DISPLAY environment variable
Error in startup script: invalid command name "tk_messageBox"
    while executing
"tk_messageBox  -icon error  -type ok  -title "git-gui: fatal error"  -message $err"
    invoked from within
"if {[catch {package require Tcl 8.4} err]
 || [catch {package require Tk  8.4} err]
} {
        catch {wm withdraw .}
        tk_messageBox \
                -icon error \
                -typ..."
    (file "/usr/lib/git-core/git-gui" line 34)

How can I solve this?

Cygwin's gitk and Git GUI require X11. 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 up and running:

1. Run the Cygwin installer again (download the relevant setup-*.exe again if you need to).
2. At the package list, select to install "xinit" 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 run echo "export DISPLAY=:0.0" >>~/.profile to have it run automatically whenever you create a new shell).

In the comments, it seems some people are getting errors stating 'couldn't connect to display ":0.0"'. If you get that, mouse over the X that should have appeared in your system tray (you may need to click the little up icon if the X icon has been hidden); the pop-up title should say something like "Cygwin/X Server:1.0". Use that ":1.0" (or whatever you see) as the value for DISPLAY in step 4, rather than ":0.0", making sure to include the colon.

If you have any other problems starting the X server, you will probably find you have a file called ~/.xsession-errors; check out the contents of that for what's going wrong. Also check whether you have a ~/.startxwinrc file, and try deleting it and seeing if that fixes the problem.

For the interested, the reason the X11 packages aren't installed automatically is that they're not 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.

Avoid X11 and add Git GUI support to Cygwin

If you want to avoid X11 (and who wouldn't?):

1. Install Git for Windows (non-cygwin) http://git-scm.com/download/win
2. Open its command shell C:\Program Files (x86)\Git\Git Bash
3. run git gui

(Optional) If you want to stay in Cygwin to launch Git GUI, add a function in your ~/.bashrc to do it. The only caveat is do not name the function git because of recursion and confusion with arguments, and the fact that you're Git for Windows shell may also be adding the same function when it starts. You may also run into path issues so be careful about setting up your paths correctly.

# Call Git GUI from Git For Windows path with `ggui`
    gg() {
    command "/cygdrive/c/Program Files (x86)/Git/bin/git" gui  2>/dev/null;


    }

When you're done editing your .bashrc, refresh your settings:

source ~./bashrc

and then simply:

gg

After spending more time than I'd care to admit, I managed to find a working solution to execute gitk from my Cygwin shell. I couldn't get any of the instructions with starting the X server to work reliably, and in the end, the solution was pretty simple.

The largest caveat is needing to have Git for Windows installed, the download for that can be found here.

Now for the whole running gitk part. Git for windows includes a cmd folder, that has a gitk.cmd windows command file. That's all you need to call to have gitk open.

$ [path-to-git]/cmd/gitk.cmd

On my system the Git path is in "C:\Program Files (x86)\Git", so the command would look like this:

$ "/cygdrive/c/Program Files (x86)/Git/cmd/gitk.cmd"

In my ~/.bash_profile file I've added a function to handle that call which looks like this:

gitk() {
  "/cygdrive/c/Program Files (x86)/Git/cmd/gitk.cmd"
}

echo "export DISPLAY=:0.0" >>~/.profile

or

echo "export DISPLAY=:0.0" >>~/.bash_profile

in my case

After following the four steps given by me_and and tititou36, you may still have issues of the XWin just die after you started the XwinServer.

The reason is it relies on a Cygwin terminal/console, which is the host, and the Xwin dies if there is no Cygwin console.

The solution for this is:

Start a Cygwin console (you can make it automatically start by putting mintty command into the file .startxwinrc under your Cygwin home directory).

Here is what worked for me:

cat >> ~/.bash_profile <<< "export DISPLAY=:0.0"

From the Cygwin package manager, do the following:

install xorg-server and some xorg fonts, xorg-x11-fonts-Type1 especially.

Next, create a link to the Windows font folders for Git GUI to use:

ln -s /cygdrive/c/Windows/Fonts /usr/share/fonts/win-fonts

Close the Cygwin terminal and open again then type

startxwin &> /dev/null &

git gui &

Based on AndrewD's answer: Don't use Cygwin's git, but use Windows Git's gitk and git gui. In other words, uninstall the git-gui and gitk packages from Cygwin (if installed). Then which gitk should point to the Windows file, not the Cygwin binary in /usr/bin.