how to set desired language in git-gui?

For Windows users the are two choices as well:

1) Set the LANG environment variable to en.

a) Overall for Windows: http://www.itechtalk.com/thread3595.html

b) For the git shell only:

If you don't want to affect anything else except git applications you might add the following line in the beginning of C:\Program Files\Git\cmd\git.cmd file:

@set LANG=en

Please note that this will only work when launching commands from the git shell - GIT GUI launched from the start menu will not be affected

2) Delete or rename relevant *.msg file in C:\Program Files\Git\share\git-gui\lib\msgs

You save on not modifying any setup shell (especially if you use cmd.exe shells) butyou lose on international functionality.

Credits: These answers originated in the official issue raised in msysgit project which can be found here: http://code.google.com/p/msysgit/issues/detail?id=302

You could remove/rename the translation file from the install, french would be

... /share/git-gui/lib/msgs/fr.msg

Don't know about OS-X, but under windows (msysgit) that would normally be C:\Program Files\Git\share\git-gui\lib\msgs\, and on Linux (and others) /usr/share/git-gui/lib/msgs/ .

(and gitk ... /share/gitk/lib/msgs/ )

Note that setting @set LANG=en in cmd file helps, but only when you start GitGUI with that cmd file. This is not the case when you start it from the Start menu: it calls wish.exe directly. If you change the link to run cmd script, it shows text command window along with GUI, which is unwanted. That is why for me renaming .msg file is a way of choice.