fried-plantains:/home/biella# whoami
root
fried-plantains:/home/biella# rm super-magical-file 
rm: remove write-protected regular empty file `super-magical-file'? y
rm: cannot remove `super-magical-file': Operation not permitted
fried-plantains:/home/biella# ls -la
total 12
drwxr-xr-x  2 biella enid  8192 May 14 14:45 .
drwxrwsr-x  7 root   staff 4096 Apr 10 23:04 ..
-rw-r--r--  1 root   root     0 Feb  4  2003 super-magical-file
fried-plantains:/home/biella#