How to verify your Ubuntu download

Tutorials
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Hello! “sha256sum” isn’t on MacOS builds by default, but there is shasum -a 256. If you run sha256sum -c SHA256SUMS 2>&1 | grep OK it will always return an empty response,

If you get no results (or any result other than that shown above) then the ISO file does not match the checksum. This could be because the ISO has been altered, or it downloaded incorrectly - either way you should download a fresh ISO from a known good source.

leading the user (including me) to thinking the iso is invalid. I assume this hasn’t been picked up before because not a ton of people verify their ISOs, even though they should. https://ubuntu.com/tutorials/how-to-verify-ubuntu#6-check-the-iso

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sha256sum -c SHA256SUMS 2>&1 | grep OK

This command give no output if the system locale is not English!

1 Like
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I just thought I’d mention that I got no results when checking my iso but the file apparently worked fine nonetheless. I downloaded it a second time and checked it again before creating the startup disk but still got no result. Eventually on the advice of a fellow community member from a local forum, I decided to assume the file was okay and proceed. Everything seems to have worked well. I still don’t know why I didn’t get the “OK”, though.

This was on Ubuntu. I am just noticing right now that someone mentioned the command sha256sum -c SHA256SUMS 2>&1 | grep OK will always return an empty response on MacOS. Maybe it was the same problem for me, or a similar one.

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I copied and pasted the command and got no results. Then I noticed that the txt file extension was missing from the command. So the command should be:

sha256sum -c SHA256SUMS.txt 2>&1 | grep OK

With this command I got a result.

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Same in French: “Réussi” is localisation for “OK”.

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The tutorials were licensed under the GNU Lesser General Public License version 3 (https://www.gnu.org/licenses/lgpl-3.0) and the initial commit is here add tutorial - how to verify · canonical-web-and-design/tutorials.ubuntu.com@d1be37f · GitHub .

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