Bash script to calculate Etag/S3 MD5 sum for very big files uploaded using multipart S3 API

Calculates the Etag/S3 MD5 Sum of a file, using the same algorithm that S3 uses on multipart uploaded files. Specially usefull on files bigger than 5GB uploaded using multipart S3 API. You can check file integrity comparing S3 Etag with the value returns by 's3md5 file'

Usage : $APP <size> <file>

- size : Multipart chunk size in MB
- file : Calculate Etag of this file

• Use 15 MB chunk size (as default in s3cmd .s3cfg config file)

  ~> s3md5 15 myfile.dat

s3md5 is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

s3md5 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with s3md5. For license details you can read LICENSE file. Also you can read GPLv3 from GNU Licenses.

Copyright (C) 2013
Antonio Espinosa
Email : aespinosa at teachnova dot com
Twitter : @antespi
LinkedIn : Antonio Espinosa
Web : Teachnova