#!/bin/sh# A sample hook to validate the branches involved in a rebase operation######################################################################### This hook is invoked right before `git rebase` starts its work and# prevents anything else to happen by returning a non-zero exit code.## The following arguments are provided:## $1 - the branch that contains the commit from which $2 was forked.# $2 - the branch being rebased or no second argument at all if the rebase applies to `HEAD`.## This example hook aborts the rebase operation if the branch being rebased is not up to date# with the latest changes from the upstream branch, or if there are any uncommitted changes.## To enable this hook remove the `.sample` suffix from this file entirely. upstream_branch=$1if [ "$#" -eq 2 ]; then  branch_being_rebased=$2else  branch_being_rebased=$(git symbolic-ref --quiet --short HEAD) || exit 0 # ignore rebases on detached headsfi # Check if the branch being rebased is behind the upstream branchif git log --oneline ${upstream_branch}..${branch_being_rebased} > /dev/null; then  echo "Warning: The branch being rebased (${branch_being_rebased}) is behind the upstream branch (${upstream_branch})." 1>&2  echo "Please update your branch before rebasing." 1>&2  exit 1fi # Check if there are any uncommitted changesif ! git diff-index --quiet HEAD --; then  echo "Warning: There are uncommitted changes in your branch ${branch_being_rebased}." 1>&2  echo "Please commit or stash your changes before rebasing." 1>&2  exit 2fi # All good, let the rebase proceed.exit 0