#!/bin/sh
set -e
# git snap: (re-)commit a snapshot of exactly another commit
# an alternative to 'pick' in git rebase -i: use x git snap <sha>
if [ -z "$1" ]; then
  echo "usage: git snap <commit sha1>"
  exit
fi

case `git cat-file -t $1` in
  commit) ;;
  *)
    echo "$1 is not a git commit"
    exit
  ;;
esac

SHA=$1
git read-tree $SHA^{tree}
git commit -C $SHA | head -n1
git reset --hard --quiet