Tip of the day.. how to use tail in d3 like in linux

Hy to all i discovery this today only
to use the "tail" inside d3 like its used in linux:
first catalog the tail program, in your current account
CATALOG DM,BP, TAIL
then
use the comando watch
for exemple:
WATCH TAIL LOG.FILE 20386 (10
this will refresh the page continuously listing the last 10 lines of the file

i don't know why but i had to catalog the program TAIL 

Wow! Cool! I work here and still didn't know that existed!

OK, I tried that and it cataloged OK, but when I did 

WATCH TAIL LOG.FILE 20386  (10

I get

The verb' WATCH' is not defined.

What have I missed?

Thanks