Need help verifying OS .iso image

Support & Help Requests
,
1

I tried verifying my ISO image of the OS I am using (Ubuntu MATE 16.04.3) using the Ubuntu MATE terminal after dragging the .iso file into my Desktop folder but when I entered the proper Sha256sum command into terminal it either says 'No such file or directory' OR it just says nothing at all.

How big of a risk is it to use an unverified ISO? I used the torrent file officially listed on the Ubuntu MATE website. Am I not doing this right? Images included below. I know, ignore where I typed 'calculate'.

Thanks!

Screenshot at 2018-01-05 03:08:50.png753Ă—476 25 KB
Screenshot at 2018-01-05 03:02:49.png754Ă—475 51.1 KB

2

If you have a good internet connection, it’s usually not too risky to assume that the ISO file has been downloaded fine. Besides, when you boot on it (after you’ve made a CD or USB key), the Ubuntu menu has an option to check the files to be sure everything is fine. The boot menu isn’t displayed by default, you have to quickly press a key when you see a keyboard logo at the bottom of the screen.

Anyway, about your issue:

  1. You have to type the command sha256sum (or md5sum or whatever) followed by the name of the file, not just the command and validate. You did it right on the first two tries of the second screenshot.

  2. You say that you put the ISO file on your desktop but you’re typing your commands from your home dir; you can see the path at the end of the prompt, which in your case is ~ (it’s a shortcut name for your home dir). That’s why it can’t find the file, it’s simply not there. You have to place yourself into your Downloads dir first:

    cd ~/Downloads
    sha256sum ubuntu-mate-16.04.3-desktop-amd64.iso

(Note: I don’t use Ubuntu in english, so I’m not sure if the folder is “Downloads” or “Download”. Adapt the first command if I got it wrong.)

2 Likes
3

Thanks I got it to work! .iso verified!

4

Welcome to the forum @Aquassassinator.

This is how I check SHA256SUMS.

1. Open MATE Terminal and type in sha256sum followed by a space.

2. Drag the .iso file to MATE Terminal and release. This will cause MATE Terminal to add the correct path to the .iso file.

Example:

sha256sum '/home/steven/Downloads/ubuntu-mate-16.04.2-desktop-amd64.iso'

3. Depress the Enter key and wait for the output.

4. If you also downloaded the SHA256SUMS file, copy the hash string from MATE Terminal

Example:

39cb4d4069dd79a9104b8c1c5d0d4a5b009779eec55fafeceafcf43c7ebcaba4

5. Open the the SHA256SUMS file in Pluma (text editor), and use the search function to search for the the hash string. If a match is found, Pluma will highlight it in the SHA256SUMS file.

Screenshot at 2018-01-05 19:15:31.png822Ă—242 140 KB

The yellow highlight makes it quick and easy to see if the the hash strings match. Thus eliminating the need to verify each character of the hash string.

Alternative Method

1. If you downloaded the SHA256SUMS file from the server, place that file and the .iso file in the same folder. The Downloads folder will work fine.

2. Open MATE Terminal and enter cd Downloads

3. Next in MATE Terminal enter the following one line script to cause Mate Terminal to check the SHA256SUMS file against the .iso file and verify that the hash is correct.

sha256sum -c <(grep ubuntu-mate-16.04.2-desktop-amd64.iso SHA256SUMS)

4. This should result in a output simular to the following example.

sha256sum -c <(grep ubuntu-mate-16.04.2-desktop-amd64.iso SHA256SUMS)
ubuntu-mate-16.04.2-desktop-amd64.iso: OK

You will need to change ubuntu-mate-16.04.2-desktop-amd64.iso to the name of you .iso file your checking.

2 Likes