lsmvictor的专栏

 检测一个无符号数是不为2^n-1(^为幂)： x&(x+1)将最右侧0位改为1位： x | (x+1)二进制补码运算公式：-x = ~x + 1 = ~(x-1)~x = -x-1 -(~x) = x+1~(-x) = x-1x+y = x - ~y - 1 = (x|y)+(x&y) x-y = x + ~y + 1 = (x|~y)-(~x&y) x^y = (x|y)-(x&y)x

转一篇讲Grep的文章，比较好 转自：http://www.panix.com/~elflord/unix/grep.html Why grep ? Back to top grep is not only one of the most useful commands, but also, mastery of grep opens the gates to master