Moving files from one hard drive to another using Ubuntu 18.x and live disk

I have 3 hard drives on this desktop, a 128gb ssd, a 1tb and a 3tb mechanical. I have booted up to a live usb version of Ubuntu, 18.x I would like to know if I can copy files from the 128gb disk to the 3tb disk using the live disk, and if so, how can I do it?

Yes, you can do that. If you open the file manager should see the other disks, and if they are not formatted oddly they should mount.

Thank you for your prompt response! All three are mounted, but I cannot move them, either by dragging or by right click. The rename, cut and move to commands are ghosted. When I use copy to it only shows me options of copying to the same drive. I can see that they are mounted. Any suggestions? It tells me that the 3tb drive is read only.

Would have to be permissions on the mounts. I don't use Ubuntu, and I wouldn't use a GUI filemanager either. Open a terminal and use "sudo cp ..."

syg00 may be correct, the live usb must have mounted the drives as root, so you do not have permission.

If you are not familiar with command line, you use the terminal to launch the gui file manager as root.Something like 'sudo naultilus' might do it.

Thank you! The live disk does not provide an icon for terminal...question one, how do I find that? All of the help I find online assumes that I can access that. Am I suffering from using a live version of the OS?

Hit the "Windows" key - start typing terminal. Else <Ctrl>-<Alt>-t will probably work.

Becomes more and more complicated...seems I need to get to the root to do these things...try su - and it asks me for a password, Thing is, I have not set up a password with this. I looked up some references...seems you must be in root to set a password

Whose on first?

First, you don't say what the live disk is. Is it an distribution installation disk? If so, which? Often live disks use a passwordless root but the password is still asked for. Have you tried simply simply hitting return when the password is asked for, or guessing something simple like 'admin' or 'root'? Perhaps if you tell us what the live disk is we will recognize it.

I assume your desktop does not have a bootable system of some sort on it or you wouldn't be using a live disk, but on the outside chance, does it?

If your live disk is something esoteric so there really is a problem would it be possible to obtain a distribution's installation disk to use? Seems like an awful lot of work to go to, but if it is really important . . . .

Sorry if I am switching the topic here, but I have a captive audience! The ubuntu was downloaded from the website...it has a complicated history I presently have 2 computers, one a win10 and one a former Mint (yes, there is a history to this problem), soon to be Ubunto box. The Linux computer has hardware issues and is not worth putting money in to fix. I am going to take the hard drives from the Linux box and put them in the windows box and make a dual boot computer. Survey says the best way to do this to install windows first, without other hard drives, then connect a hard drive and install Ubuntu on it without the windows drive hooked up to it, then add the data drives. Is this a valid sequence? I can google to find the method to do the dual booting...but the urgent question...once I have a full, stable version of Ubuntu up and running, will I be able to easily access these 2 hard drives? I am new at Linux...have been using Mint for a while, learning a bit here and then...and then this. I have read that Ubunto is better at managing multiple hard drives automatically.

..try su - and it asks me for a password

That is because the Ubuntu developers have chosen to disable the root user by default and on their live/install media, you need to use sudo. Explained at the link below.

https://help.ubuntu.com/community/RootSudo

First thing you would need to post here is which windows version are you using? Are you using GPT drive(s)? Are you going to do UEFI installs? If you want to boot both windows and Ubuntu from Grub you will need to update grub after the Ubuntu install with the windows drive attached and both windows/Ubuntu will need to be installed in the same mode (both UEFI or both Legacy). Your data partitions on the other drives will need to be formatted with something like vfat or ntfs as a default install of windows is not capable of accessing/reading/writing to a Linux filesystem.

Ubuntu has a site which has been available for years on dual booting with windows 10 UEFI which would probably be useful reading in your case.

https://help.ubuntu.com/community/UEFI