The sub-shell (wrapped in parentheses) performs a series of tasks-albeit sleep delays in this contrived example-and emits output to a Zenity progress meter via a pipe.
sub - shell(包含在括号中)执行一系列任务—在这个人为例子中albeit sleep延迟—且通过一个管道将输出发出到一个Zenity过程表。
2
The system function opens a subshell and executes the contents.
system函数打开一个子shell并执行相关内容。
3
When a command or the bash shell itself initiates (or spawns) a new shellsub-process to perform a task, it is known as forking.