Easy way to Verify Ubuntu ISO?

Question

Is there an easy way to verify the Ubuntu ISO? The tutorial here from canonical seems very difficult just to verify an iso of ubuntu 24.04

Answer 1

Go to the releases page https://releases.ubuntu.com/

Below is 24.04 https://releases.ubuntu.com/noble/

Click on the Sha256Sums link and right click and "save as" SHA256SUMS.txt (it will choose the name automatically) Make sure the iso and the checksum are in the same directory.

Then type this

sha256sum -c SHA256SUMS.txt --ignore-missing

You will get an OK message and a warning.

:~/Downloads$ sha256sum -c SHA256SUMS.txt --ignore-missing
ubuntu-24.04-desktop-amd64.iso: OK
sha256sum: WARNING: 1 line is improperly formatted

I hope this helps. The tutorial on the website is far more complex than it really needs to be. That is the problem with linux.

Someone asked.. "What is the use if the sha256 is not valid?" I think the ancient old instructions were before https was enforced with all browsers. Here is a screenshot below:

You can also use the usb image writer's verification by pasting url

Answer 2

After verifying the ISO is good and using it to create a bootable thumb drive, you can double check everything went ok by removing the thumb drive, plugging it back in, and running these two commands:

cd /media/YourUserName/'Ubuntu 24.04 LTS amd64'/

md5sum -c md5sum.txt | less

The first command CDs you to the thumb drive and the second uses the md5sum file on the thumb drive to verify that all the files are intact and readable.