On Windows, the sublime_text.exe program has a couple of command line options that help here. The
-n option causes a new editing window to be created and the
-w option tells Sublime Text to wait until you close the window before returning.
By default, the Sublime Text 3 installer puts everything into “C:\Program Files\Sublime Text 3”. The spaces in the folder names makes the git command to configure the editor slightly trickier than normal. The following command sets up the global editor for git.
git config --global core.editor "\"C:\Program Files\Sublime Text 3\sublime_text.exe\" -n -w"
You can check that the configuration has been correctly stored with
git config --global -l