use Meld for git diff

1. make a script, git-meld.sh #!/bin/bash meld "$2" "$5" > /dev/null 2>&1
2. put the script in the bin directory sudo mv git-meld.sh /usr/local/bin/ sudo chmod +x /usr/local/bin/git-meld.sh
3. add diff settings in the $HOME/.gitconfig [diff]     external = /usr/local/bin/git-meld.sh