hi all,

how do you do a checksum of a file folder, i want to use sha512 as md5 is cracked

file -


sha512 path/to/file/file.tar


folder -


find -s path/to/folder -type f -exec sha512 {} \; | sha512


many thanks,

rob

First, someone has to have made a list of files and their checksums. You can do that, if the files are yours and you know they are good.

Then once you have a file with the checksums with two columns, the first being the checksum, the second being the file name, someone else receiving the files in question plus the checksum file can verify it.

The checksums are intended to guarantee integrity. Often for further guarantees of authenticity, the checksums are usually signed with OpenPGP. The utility gnupg, version 1.x can do that.

what does the option -c do

also i imagine your first code i will put it in a script?

From the manual page for sha512sum it says:

The first draft, before the edit, was more script-oriented.

so cant i do just

sha512 filename.tar

or should it be

sha512 -c filename.tar

i thought your first code was to be put in a script, i will do that and get back to you

thanks man

This will generate a checksum and save it in a file:

The following will use that checksum file to verify the other file(s)

It's kind of pointless to do both yourself. Usually that second step is done by someone else to verify that a transfer was successful.

It looks like you missed a very important point: check in this case means you check your file against an external information, which is called checksum (and actually is another file)
Usually you download a file and a checksum too and you can check if the checksum of the given file is identical to the checksum downloaded. (if yes we assume the downloaded file is ok, if not we assume the download was unsuccessful.
creates the checksum
checks if that checksum is valid

ok i have done a file by doing this -

sha512 Even\ When\ I\ Fall\ -\ January\ 2017\ Project.tar

how do i do a directory now

many thanks,

rob

what do you mean by that?
And again, what do you want to do? I'm afraid, there is no such thing for directories, but files.

sorry i mean this -

sha512 Even\ When\ I\ Fall\ -\ January\ 2017\ Project.tar
SHA512 (Even When I Fall - January 2017 Project.tar) = fa8a0c210f4616f27de9e66d5316bce62881baf794214ebecbf4a6fd576e09b274b278f0bef278315e12159083073975f02e 5f03aff18682e5273722287df799

ok so now i know what the checksum is for the tar file

now i want to find out what the checksum is for the directory (i created the directory into the tar file)

i want to check if the two have the same checksums

There can be no checksum for the directory itself, it is not a file, only for any files that might be in the directory.

only files can have checksums, and if that dir could have a checksum that would be definitely different (so not the same as the one you posted)

What you clearly want to do is crc check a tar file. gzip does this, so if you gzip the tar using the z command line option it will add the checksum.

Refer to tar(1), gzip(1)

And this:

wow, wasnt expecting this, im getting all different checksum values

i think i will extract the tar and cross reference it with the source directory ie do on both

count number of files

size of directory

SHA512 (/vol/cha-work/_ARCHIVE/to_be_archived/audio/chad_r/2017-05-17/Even When I Fall - January 2017 Project.tar) = fa8a0c210f4616f27de9e66d5316bce62881baf794214ebecbf4a6fd576e09b274b278f0bef278315e12159083073975f02e 5f03aff18682e5273722287df799

find -s /vol/cha-work/_ARCHIVE/to_be_archived/audio/chad_r/2017-05-17/Even\ When\ I\ Fall\ -\ January\ 2017\ Project/ -type f -exec sha512 {} \; | sha512
9bc5b7f9b2dcf68fc5b113cd359282e34876ad796c43e5b16701c9ff0cba3ba3b038af67db9f8a8dbadfa6d22ee3584f1c4a c840b710c5f422d7435f59c09c42

tar -cf - Even\ When\ I\ Fall\ -\ January\ 2017\ Project/ | sha512
ac81d3bc9dc843fd4c7d6e6bdbc477076437727044f291b5c162232efb8e8747c8b2d2bd82567e381ea235d158fba5d28e3c 5eab9a60a86acba6b452960bb7da

You're sending different data to sha512. In the first line, you send only the file itself to sha512 and then make an SHA512 hash of that hash. In the second line, you are providing a complete tarball to it.