Making a file unalterable with chattr
You can make a file "unalterable" so that it cannot be changed or deleted even by root. To set it up :
chattr +i /path/to/file
After that the file is untouchable, it can only be read, and it cant be deleted or altered even by root.
To update the file firstly we need to remove the attribute using the -i flag:
chattr -i /path/to/file
To get the attrs list we do:
lsattr /path/to/file