This topic describes how to run the hash command to calculate the MD5 hash or CRC-64 of a local file.

Notice Sample command lines in this topic are based on the 64-bit Linux system. For other systems, replace ./ossutil64 in the commands with the corresponding binary name. For more information, see ossutil.

Command syntax

./ossutil64 hash localfile [--type=<value>]

The following table describes the parameters that you can configure when you run the hash command.

Parameter Description
localfile The full path of the local file you want to upload.
--type The method used to calculate the value of the local file. Default value: crc64. Valid values:
  • md5:

    If --type is set to md5, the MD5 hash and Content-MD5 value are displayed at the same time. The Content-MD5 value is obtained by calculating the MD5 hash to obtain a 128-bit number, and then encode the number in Base64. For more information about Content-MD5, see RFC 1864.

  • crc64

    The CRC-64 is calculated by using Standard ECMA-182.

After you upload the local file to the specified bucket, take note of the following items when you want to query or use the CRC-64 or MD5 hash:

  • You can use the X-Oss-Hash-Crc64ecma field to query the CRC-64 or the Content-Md5 field in the stat command to query the MD5 hash of the local file. For more information, see stat.
  • If you upload a local file before Object Storage Service (OSS) supports CRC-64, the stat command cannot be run to query the CRC-64 of the local file.
  • If you upload a local file by using append upload or multipart upload, the stat command cannot be run to query the Content-MD5 value of the local file.

Examples

  • Calculate the CRC-64 of the test.txt local file 
    ./ossutil64 hash test.txt --type=crc64
CRC64-ECMA                  : 295992936743767023
  • Calculate the MD5 hash of the test.txt local file 
    ./ossutil64 hash test.txt --type=md5
 MD5                         : 01C3C45C03B2AF225EFAD9F911A33D73
 Content-MD5                 : AcPEXAOyryJe+tn5EaM9cw==