Hello.
I changed "resolv.conf" file via "chattr" command to read only but when I use "sudo chattr -i /etc/resolv.conf" my file permission can't change

$ ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 68 Sep 11 20:12 /etc/resolv.conf

Any idea?

Technically, +i isn't read only. It's immutable. As in, nothing can make changes to it of any kind, including deletion, renaming, linking, moving.

Have you tried doing a then trying to clear the immutable attribute? I believe this should work, as sudo chattr you're changing as yourself with root privelages, but the immutable attribute can only be cleared by superuser, not just as a normal user with escalated privelages.

However, why exactly did you want to make the file immutable in the first place if you don't mind my asking?

FIRST why are you looking to change the attributes of /etc/resolve.conf in the first place?

If you need to make a change, you can edit the file using sudo vi or sudo vim.

To do what you want use chmod(1).

And since this file is owned by root, you'll need to use sudo(8) for this.

The attributes affected by chattr do not affect the permission bits shown by "ls -l". You need to use lsattr to see them.

I was confused when the OP stated that they made the file read-only.

Still, I wonder why they're messing with that file.

root user can't remove and change permission too :

# rm /etc/resolv.conf
rm: cannot remove ‘/etc/resolv.conf’: Operation not permitted

# chmod +rw /etc/resolv.conf
chmod: changing permissions of ‘/etc/resolv.conf’: Operation not permitted

It i so odd !!!!!!!

Until you remove the "immutable" attribute ("chattr -i /etc/resolv.conf"), nobody modify the file, create or remove a hard link to the file, or change its permissions. About all than can be done is to add or remove "chattr" attributes.

I think I remember there was a thread about permission in running the www folder and ways to get stuff going. Chattr was mentioned there. If I remember correct though, it was as a measure to protect files served by apache that does not require modification.

Op please turn off immutable on resolv.conf, that is asking for headache down the line. It really is not required on that file.

I used "chattr -i /etc/resolv.conf" but not matter

as the actual root user, not as sudo?

Problem solved via "chattr -ai /etc/resolv.conf" as root.