Reference(s):
http://www.sourcegear.com/diffmerge/downloads.php - get the installer version, NOT the dmg version
git config --global diff.tool diffmerge
git config --global difftool.diffmerge.cmd 'diffmerge "$LOCAL" "$REMOTE"'
git config --global merge.tool diffmerge
git config --global mergetool.diffmerge.cmd 'diffmerge --merge --result="$MERGED" "$LOCAL" "$(if test -f "$BASE"; then echo "$BASE"; else echo "$LOCAL"; fi)" "$REMOTE"'
git config --global mergetool.diffmerge.trustExitCode true
git config --global mergetool.keepBackup false
Any time you encounter a merge conflict, just do git mergetool
Via brew installing of diffmerge looks simple:
brew install --cask diffmerge