bash - 为什么管道重置当前工作目录？

Question

第一个脚本:

$ { mkdir dir; cd dir; pwd; } | cat; pwd;
./dir
.

第二个脚本:

$ { mkdir dir; cd dir; pwd; }; pwd;
./dir
./dir

为什么这个| cat 对当前目录有影响吗？以及如何解决？我需要第一个脚本与第二个脚本完全一样。我不希望 cat 将当前目录更改回 .。

Answer 1

引自manual :

Each command in a pipeline is executed in its own subshell (see Command Execution Environment).

另见 Grouping Commands :

{}

   { list; }

Placing a list of commands between curly braces causes the list to be executed in the current shell context. No subshell is created.