I changed "other" permissions to none for bin, etc and dev folders as root, and now there is no access to terminal, programs, also no possibility to login in a window as admin. When I was still using the terminal after changing these permissions, shortly before the terminal stopped to be displayed by Ctrl+Alt+T, the format <[email protected]:~$> changed to <I have no [email protected]:~$> and a folder with PCname in home/username directory was created.
I'm using Ubuntu Mate 18.04.1. I didn't shut up the PC for a few days, so a folder var/log/tiger (as superuser) is still opened and I can create files there, but can't copy.
At #ubuntu by support I was advised to boot from a different but compatible file system or Ubuntu Live CD and change the permissions from there. But they said that PC may not also properly boot up, so I'm not shutting it down yet. They also didn't provide an estimate of how likely will it be possible to restore "other" permissions to at least the bin folder if booting up and mounting a compatible file system.
Can you advise on how to handle permissions to bin folder while booting from Live CD?
I wrote an Ubuntu Mate 18.04.3 .iso image to an USB stick (18.04.1 not available for download) and it seems to start ok in active current GUI session, despite that I set "other" permissions to 0 for /dev also.
I thought that as an alternative for booting from a Live CD it would be better to have some "Root restore tool" bootable from an USB stick into active GUI session. As I have another PC with Ubuntu Mate 16.04, there I could write this app onto USB stick to be bootable from USB and enter and save my Ubuntu Mate 18.04 root password into this app. So that after inserting into PC with 0 "other" permissions for bin folder it would access the file system already as root so I could change the permissions in current active GUI session.
Does such tool already exist or is it very difficult to write such script to be root-bootable from USB?