Abdul Rahman bin Osman or known by his stage name Man Bai (born30 November 1967)is a Malaysian rock singer since the 1980's. He was the vocalist for the group band Gersang. Abdul Rahman bin Osman or known by his stage name Man Bai (born30 November 1967)is a Malaysian rock singer since the 1980's. He was the vocalist for the group band Gersang.