My OS drive won't boot

I made a huge mess of my system partition. Now instead of booting, it offers me Grub. I am able to boot from the USB, of course, but I don't know enough about the command line yet to get to my system partition. If I could, I think even I could repair it. I think I have my data backed up. I managed to do that. I'd rather not reinstall. Especially when I have system images taken with Timeshift. If I knew how to get to the images when I can't boot.

Here's what happened:

I found my pc slowing and freezing, and then noticed my OS drive was packed. Indications were I had 60 gig left on a half ter partition. So, I uninstalled apps until I had had 90 gig. Then I updated and ran Bleachbit. It froze right after it gave a message that I only had a half gig of space and needed to empty the trash. Oops! Forgot about that, but it had already crashed.

And it won't boot now. If I could just get to the drive and empty the trash, it'd probably boot again, provided bleachbit didn't damage it.

Suggestions?

If you can see Grub, you should be able to access terminal. use Advanced Options for Zorin then, Recovery
Arrow key to Enable Networking
Once done, back up to the menu, then arrow key down to Drop To Prompt.
First clear your trash, etc. The easiest may be (do not worry, it is a tiny CLI app):

sudo apt install trash-cli

trash-empty

Now:

sudo apt clean && sudo apt autoremove

Once done, restore desktop:

sudo apt install --reinstall zorin-os-desktop

Hopefully, that is all that is needed...
60 gigs of 500 remaining... Are you gaming or saving a LOT of files? Or is that shrinkage a shock to you?
I ask in case that was unexpected and there is a backlog of errors building up...

I am pretty sure there way a way to trigger loadng timeshift backups from GRUB, some distros even have that set-up by default, though I'd need to look up if we can do that manually :thinking:

I've relied a lot on redundancy, and have to clear some of it. How I do I recover a few of the files in the trash? I think what must've happened was I cleared space on one of my backup-data drives before backing up my current data. I forgot those go to the trash bin as well. That's the only way I could have suddenly consumed 90 gigs again. I dont think it could have been malware.

If trash has already been emptied, you would need to use Recovery software like DiskDigger.
If it has not been emptied, there are two trash bins- one in Home and one in Root.
~/.local/share/Trash
/root/.local/share/Trash

No fault of you, or anyone else here, but I've made no progress at all.

I know I should hit the left shift key at the right time, and it's hard to do, but so far, I haven't seen a trace of Advanced Options for Zorin.

I'll clarify my question: how do use the terminal from a flash-drive boot to get to my hard drive? I know how to change directory, I know how to list my hard drive, now how do I get to my hard drive and run commands that affect it?

If I knew that, I think I could figure the rest out. Right now I'm just looking through the help list of commands, trying to find the right ones.

Presume I know absolutely nothing about this and any gap in instruction might bring me to a screeching halt.

Yes, you must I.D. and mount your hard drive, while booted into Live CD...
A Full Fledged Guide may be more helpful than a post:
https://help.ubuntu.com/community/LiveCdRecovery

you can just hold it lol
no need to time anything

that is indeed a thing

there is a command called chroot, it is short for "Change Root" and it's purpose is, well, to change the Root directory

it's useful for accessing a drive through a USB, as you mentioned

what you want to do is the following:

mount your drive
see where it is mounted either through properties or the Disks tool
run the following:

chroot --userspec=root:root /wherever/your/hard/drive/is/mounted/

from that point on, you're operating as if you were booted into your Zorin installation (pretty much, at least)

thus, you can run commands like sudo apt upgrade for instance, or diagnose the system, do whatever you want really

Edit:

in that case

the disks tool which is included shows the location a drive is mounted at as the last little bit of information after selecting a partition, here I show my USB Flash Drive for instance:


"NTFS - Eingehängt in media/rush/80482A50482A456E"

I'm going by my memory of Aravisian's own instructions in another post I read in my vast browsing on this subject. Apparently, it works differently then for entering bios. But just in case, I tried leaning on it this time. Is anybody ready to break it to me that Grub is Zorin's advanced options? Because that's the only thing that comes up from my hard drive, with or without the left shift key.

Left shift is for Legacy Install (MBR).
Try esc or tab if using EFI (UEFI).

Hey, thank you both. That gives me something to start with tomorrow. I expect to solve it, then.