When was stdbuf introduced?

[Peng Yu]

Hi,

I see stdbuf available in coreutils.

http://www.gnu.org/software/coreutils/manual/html_node/stdbuf-invocation.html

But I don't find it in my system. Was stdbuf just introduced recently?
Or there is something wrong with my installation?

~$ wc --version
wc (GNU coreutils) 8.21
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Paul Rubin and David MacKenzie.
~$ which stdbuf 2> /dev/null || echo $?
1
~$ uname -o
Darwin

-- 
Regards,
Peng