Git External merge and difftools Setting up KDiff3 as merge tool
Example
The following should be added to your global .gitconfig file
[merge]
tool = kdiff3
[mergetool "kdiff3"]
path = D:/Program Files (x86)/KDiff3/kdiff3.exe
keepBackup = false
keepbackup = false
trustExitCode = false
Remember to set the path property to point to the directory where you have installed KDiff3
