/prog/ challenge 2009: tskbot

Create a program which accepts a string on stdin, and outputs to stdout either the string ``tsk'', or an empty string. The formar case happens when the input string contains the substring ``nigger'' (case-insensitive). The latter happens in other cases.

Shortest program wins. You have 7*24 hours from the timestamp of this poast. Good luck!

Would specifying flags for the program be cheating? If you do sed -n, you can do
s/nigger/tsk/ip
otherwise I need to add two characters more
s/nigger/tsk/ip;d
This requires GNU sed.