How do I change file system in recovery mode to read-write mode?

Question

I have messed up my sudoers file and I want to change the permission on it.

When I login in recovery mode, I cannot run the command chmod as it is read-only option.

I tried mount -o remount,rw / in recovery mode. Didn't work for me:

Err : Ext4-fs remount. Opts errors=remount-ro

How can I boot into recovery mode and with read-write option?

score 197 · Answer 1 · edited Nov 09 '16 at 17:14

197

I did some web searching on "Recover Mode Read Only" and came across this post on LinuxQuestions.org website.

Shutdown the computer
Boot into Recovery Mode --After BIOS load, hold down Shift key to access the grub menu --Once in grub menu, select the entry ending in "(recovery mode)"
From the next menu selected option to enter Root Session
At the root session, execute command mount -o rw,remount / to remount the filesystem as read-write

edited Nov 09 '16 at 17:14

Cristiana Nicolae

4,500

answered Apr 01 '12 at 16:54

twister_void

5,924

I get: "mount: special device remount does not exist" – Rishabh Agrahari Feb 03 '19 at 18:54
2

@RishabhAgrahari You'll get that message if you added a space after "rw" in the command (ask me how I know :) ).
It's as-written: mount(space)-o(space)rw,remount(space)/
– 8bitartist Apr 27 '19 at 05:22
@8bitartist Lol, true. Why is it like this? – Rishabh Agrahari Apr 28 '19 at 06:04

score 21 · Answer 2 · answered Jun 22 '15 at 02:16

21

Since the answer is a bit old and did not work for me, I share with you my solution. I mistyped an option in fstab for the / directory (very bad, I know).

In order to mount in recovery mode with read write option the mentioned solutions did not work for me.

I simply chose the kernel with recovery mode option and pressed e to modify the boot parameter from ro to rw.

answered Jun 22 '15 at 02:16

Ely

459

1

+1 for an alternate solution, even if it might not be ideal in many cases. – Stunts Sep 18 '15 at 23:22
2

Your answer is gold! – reexmonkey Aug 09 '19 at 15:11
Finaly... Best solution – Vitalicus Jan 21 '20 at 23:56

score 19 · Answer 3 · answered Aug 28 '13 at 16:52

19

I always use following way to change into read/write mode

Login in Safe Mode
From the Menu just go to Grub option, it will give a message like Updating grub will mount your system in read/write mode. Just chose yes to mount your system in read/write mode. It will update your grub and will exit from Grub menu.
Finally login as root, your system will be in read/write mode.
You can also chose dpkg option from the menu to change file system to read/write mode.

It always worked for me. It helps when you don't remember the command to change into read/write mode.

Just give it a try..

answered Aug 28 '13 at 16:52

Saurav Kumar

14,916

what does "login in safe mode" mean? – gman Oct 10 '18 at 00:43
@gman: Safe Mode is kind of login without the GUI part! You can do so by holding Shift while your system restarts. You'll get a GRUB menu from where you can choose to login in SAFE MODE – Saurav Kumar Oct 15 '18 at 14:50
@gman recovery mode – mchid Jul 30 '19 at 07:12

How do I change file system in recovery mode to read-write mode?

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