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If I test an archive will it verify the CRCs?

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mccoyn
2014-09-17
2014-09-22
  • mccoyn

    mccoyn - 2014-09-17

    I have some large archives that I made that are 10 to 20 GB in size. I would like to verify that the archives contain the original files without corruption, but I don't have space to decompress them and diff. What I would like to do is create a list of files with their CRCs and diff it to a list created from the archive with all the files and the CRCs reported in the archive. If these lists match I will use the test command on the archive and if that passes delete the original files. This works on the assumption that the test command will fail if the CRCs are incorrect. Is this assumption valid?

     
  • Igor Pavlov

    Igor Pavlov - 2014-09-18

    yes, you can do it.
    Also 7-Zip can calculate sum of CRCs in archive and disk.

    7z t a.7z -scrc
    7z h c:\dir\*
    

    So you don't need to check each file, if sums are same.

     

    Last edit: Igor Pavlov 2014-09-18
  • mccoyn

    mccoyn - 2014-09-22

    I didn't see these options, but after upgrading from 9.20 to 9.30 I was able to do it. I had to wait until some long compression operations were completed to upgrade. Now that I have, it looks like this will work. Thank you.

     

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