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?