Change git commit time and author time

change_commit_time.sh

#!/usr/bin/env bash

usage() {
    echo "Script for rewrite commit time"
    echo 'Usage: ./gitignore_change_commit_time.sh --num 1 --time "$(date -v-46H)"'
    echo "  --num [NUM] ex: 3"
    echo "  --time [DATETIME] ex: 'Fri Nov 24 16:00:00 2017'"
    exit 1
}
for OPT in "$@"
do
    case "$OPT" in
        '-h'|'--help' )
            usage
            exit 1
            ;;
        '-v'|'--version' )
            echo $VERSION
            exit 1
            ;;
        # required params
        '--num' ) if [[ -z "$2" ]] || [[ "$2" =~ ^-+ ]]; then echo "$PROGNAME: option requires an argument -- $1" 1>&2; exit 1; fi
            E_TAR_NUM=t;TAR_NUM="$2"; shift 2 ;;
        '--time' ) if [[ -z "$2" ]] || [[ "$2" =~ ^-+ ]]; then echo "$PROGNAME: option requires an argument -- $1" 1>&2; exit 1; fi
            E_DATETIME=t;DATETIME="$2"; shift 2 ;;
    esac
done

# #
# check required params
# #
[ "${E_TAR_NUM}" != "t" ] && echo "param [NUM] is missing." && usage
[ "${E_DATETIME}" != "t" ] && echo "param [DATETIME] is missing." && usage


function confirm {
  echo -n "Is it OK ? [y/n]"
  read answer
  if [ "$answer" != "y" ]; then
    echo "Stoped"
    exit;
  fi
}


echo "You're going to exec:"
echo "$   git rebase -i HEAD~$TAR_NUM"
echo "$   git commit --amend --date=\"${DATETIME} +0900\""
echo "$   git rebase --continue"
echo "$   git rebase HEAD~$TAR_NUM --committer-date-is-author-date"

confirm

git rebase -i HEAD~$TAR_NUM
git commit --amend --date="${DATETIME} +0900"
git rebase --continue
git rebase HEAD~$TAR_NUM --committer-date-is-author-date

echo ""
echo "-----------"
echo "FINISHED:"

echo "$ git log --pretty=fuller -n $TAR_NUM"
git log --pretty=fuller -n $TAR_NUM