bash function to implement a non-destructive git rebase

git-squash.sh

# Like git-rebase -i, but without touching the index or working tree.
function git-squash() {
    if [ "$1" == "" ]; then
        echo "usage: git-squash <number_of_commits_to_squash>"
        return
    fi

    # note the current HEAD commit
    old_head=$(git rev-parse HEAD)
    echo "Current HEAD: $old_head"

    # http://stackoverflow.com/a/5201642
    git reset --soft HEAD~$1 && git commit --edit -m"$(git log --format=%B --reverse HEAD..HEAD@{1})"

    # print undo action
    echo
    echo "To undo this change: git reset $old_head"
}