Finally, we'll add an arbitrary 30-second sleep to ensure the command sequence finishes after the two subshells do.
最后，我们添加任意30秒的休眠时间，确保两个subshell完成之后命令序列完成。
2
To demonstrate the use of nice to set priorities, let's start two copies of the count1.sh script in different subshells at the same time, but give one the maximum niceness of 19.