Hi, Richard Owlett > I used "linux tutorial chmod chattr" [w/o quotes] in both DuckDuckGo and > Google.
A general search topic would be "linux file permissions" and "chattr". I can show you an example shell session on an ext4 filesystem. I create a directory with a file and take away w-permissions: $ cd /home/thomas/test $ mkdir my_private_dir $ echo private_content >my_private_dir/my_private_file $ chmod a-w my_private_dir/my_private_file $ chmod a-w my_private_dir Now normal users including myelf cannot change the file content and cannot rename or remove the file $ echo new_content >my_private_dir/my_private_file bash: my_private_dir/my_private_file: Permission denied $ mv my_private_dir/my_private_file my_private_dir/renamed_private_file mv: cannot move ‘my_private_dir/my_private_file’ to ‘my_private_dir/renamed_private_file’: Permission denied $ rm my_private_dir/my_private_file rm: cannot remove ‘my_private_dir/my_private_file’: Permission denied But the superuser can override this without needing to use chmod # cd /home/thomas/test # echo foul >> my_private_dir/my_private_file # cat my_private_dir/my_private_file private_content foul # mv my_private_dir/my_private_file my_private_dir/renamed_private_file # ls -l my_private_dir total 4 -r--r--r-- 1 thomas thomas 21 Jan 1 18:58 renamed_private_file Now comes "chattr +i". Only the superuser can apply it. After restoring the old filename and content, i do: # chattr +i my_private_dir/my_private_file This keeps even the superuser from spoiling the file # echo foul >> my_private_dir/my_private_file bash: my_private_dir/my_private_file: Permission denied # mv my_private_dir/my_private_file my_private_dir/renamed_private_file mv: cannot move ‘my_private_dir/my_private_file’ to ‘my_private_dir/renamed_private_file’: Operation not permitted The protection does not depend on missing w-permissions of the directory: # chmod u+w my_private_dir # rm my_private_dir/my_private_file rm: cannot remove ‘my_private_dir/my_private_file’: Operation not permitted or missing w-permissions of the file file: # chmod u+w my_private_dir/my_private_file chmod: changing permissions of ‘my_private_dir/my_private_file’: Operation not permitted even if the superuser temporarily allows the change and them runs "chattr +i" again: # chattr -i my_private_dir/my_private_file # chmod u+w my_private_dir/my_private_file # chattr +i my_private_dir/my_private_file # echo foul >> my_private_dir/my_private_file bash: my_private_dir/my_private_file: Permission denied ---------------------------------------------------------------------- I can of course not comment on what particular GUI tools do when they promise the user to make something "Read-only". (... or what systemd is willing to do for its clients ....) Have a nice day :) Thomas
