PGAGetIntegerFromGrayCode(1) on Linux

The text 18a9d989a957, as Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze), Debian 5.0 (Lenny) shipped it. The page shows this text now.

interpets a binary reflected Gray code sequence as encoding an integer value and returns the integer value it represents.