Tag Archives: Synology

Getting file checksum on Synology

cksum utility can calculate the file checksum using 3 different algorithms. The third one is the well-known CRC32.

  • CRC32 of a single file: cksum -o3 filename
  • CRC32 of all files in the current directory: cksum -o3 *

To verify the checksum in Windows, I recommend using HashTab. After installing it, just check the proerpties of a file and compare the CRC32 value returned by HashTab to the value calculated by cksum. Note that HashTab shows CRC32 as a hex number while cksum shows a decimal value; you can use an online converter to compare the two values.

Example (for some file on my Synology):

ds414> cksum -o3 mrr40320.JPG
946866417 14531 mrr40320.JPG

The first number returned by cksum is the CRC32 value, the second the file size in bytes.

Value returned by HashTab for this file is 387008F1 which is the same as 946866417 returned by cksum.

Does anybody know what the 1st and the 2nd algorithms of cksum are? 

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