Global .gitconfig settings for external diff/merge tool (Note: The order is important)

Global.GitConfig

[mergetool "kdiff3"]
    path = /usr/local/bin/kdiff3
    keepBackup = false
    trustExitCode = false
[mergetool "diffmerge"]
    cmd = /Applications/DiffMerge.app/Contents/MacOS/diffmerge --merge --result=$MERGED $LOCAL $BASE $REMOTE
    keepBackup = false
    trustExitCode = false
[merge]
  tool = diffmerge 
[difftool "kdiff3"]
    path = /usr/local/bin/kdiff3
    keepBackup = false
    trustExitCode = false
[difftool "mvim"]
    path = /usr/local/bin/mvim
    keepBackup = false
    trustExitCode = false
[difftool "diffmerge"]
    cmd = /Applications/DiffMerge.app/Contents/MacOS/diffmerge $LOCAL $REMOTE
    keepBackup = false
    trustExitCode = false
[difftool]
    prompt = false
[diff]
	tool = diffmerge