$ whoami admin $ sudo -- sh -c 'f="/home/admin/.bashrc"; chown root:admin $f; chmod 640 $f ; chattr +i $f' $ ls -al /home/admin/.bashrc -rw-r---

$ whoami admin $ sudo -- sh -c 'f="/home/admin/.bashrc"; chown root:admin $f; chmod 640 $f ; chattr +i $f' $ ls -al /home/admin/.bashrc -rw-r----- 1 root admin 1445 Jan 31 09:53 /home/admin/.bashrc $ rm /home/admin/.bashrc rm: cannot remove '/home/admin/.bashrc': Operation not permitted $ echo "writing?" >> /home/admin/.bashrc -bash: /home/admin/.bashrc: Operation not permitted