bitwise operator

基本解释

Bitwise-or adds bits to the resulting expression, whereas bitwise-and selects only those bits in common between its two operators.
按位或向结果表达式添加位，而按位与只选择两个运算符之间相同的位。
The shell doesn't have a large collection of arithmetic operators, but it's sufficient for most programming tasks, including bitwise shifts, remainders, and comparisons.
Shell 并没有提供大量的算术操作符，但是已经足以完成大多数编程任务，包括移位、求余和比较。
The arithmetic and concatenation operators have the order of precedence described in the following section, and all have greater precedence than the comparison, logical, and bitwise operators.
算术和串连运算子优先顺序如下节所述，其优先顺序都高于比较运算子、逻辑运算子和位元运算子。