fixtimestamp.sh - fix timestamp

fixtimestamp.sh

#!/usr/bin/env bash
#
# fixtimestamp.sh - fix timestamp
# Copyright (c) 2019 Koichi OKADA. All rights reserved.
# This script is distributed under the MIT license.
#

if (( $# <= 0 )); then
  cat <<-EOD
	Usage: ${0##*/} [OPTIONS] <shifted_time> <correct_time> [<files> ...]
	EOD
  exit
fi

SHIFTED_TIME="$(date -d "$1" "+%s.%N")"
CORRECT_TIME="$(date -d "$2" "+%s.%N")"
shift 2

for i; do
  TIME="$(date -r "$i" "+%s.%N")"
  FIXED_TIME=$(perl -e "print $TIME - $SHIFTED_TIME + $CORRECT_TIME" )
  echo touch -d \"@$FIXED_TIME\" \"$i\"
done