$ sudo mkdir /usr/local/bar
$ sudo touch /usr/local/bar/foo
$ ls -l /usr/local
total 11M
drwxr--r--  2 root root 4,0K jul 24 23:56 bar/
[...]
$ ls -l /usr/local/bar/
ls: cannot access '/usr/local/bar/foo': Permission denied
total 0
-????????? ? ? ? ?            ? foo
$ sudo ls -l /usr/local/bar/
total 0
-rw-r--r-- 1 root root 0 jul 24 23:56 foo

Defaults    env_reset
Defaults    mail_badpass
Defaults    secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

root    ALL=(ALL:ALL) ALL

%admin ALL=(ALL) ALL

%sudo   ALL=(ALL:ALL) ALL

#includedir /etc/sudoers.d

myusername  ALL=NOPASSWD: ALL