$ cat /post/ubuntu-recovery-mode-mounting-read-only-filesystem.md
Ubuntu recovery mode mounting read only filesytem
I recently made some changes to my /etc/X11/xorg.conf file which backfired and Ubuntu (12.10 in this case) would crash while loading the operating system.
It should be simple enough to undo the last change you made to a system file when booting into recovery mode, but alas it is not straightforward because when booting into recovery mode the filesystem is mounted as read-only! Oh dear!
- Boot into the Advanced options → Recovery Mode entry on the GRUB menu (hold Shift during boot if GRUB is hidden).
- From the recovery menu pick “Drop to root shell prompt” (exact wording may vary slightly by Ubuntu version).
- Enter the following command to remount your filesystem as read-write:
mount -o remount,rw /- Make the required changes to your operating system and then exit /
reboot.
The mount -o remount,rw / incantation is the evergreen part — it has worked unchanged from Ubuntu 12.10 through every release since.