bash - bash 中 `<(...)` 'operator' 的名称是什么？

Question

我熟悉为 bash 中的命令输入创建“临时文件”，例如

cat file_1 <(echo hello) file_2

我想阅读有关该主题的更多信息，但我不知道 <( ) 的名称运算符(operator)。我怀疑这是一种 IO 重定向。

这个符号/运算符有名称吗？

Answer 1

这叫做 process substitution :

Process substitution is a form of redirection where the input oroutput of a process (some sequence of commands) appear as a temporaryfile.

同样来自 Bash Reference Manual → 3.5.6 Process Substitution :

Process substitution allows a process’s input or output to be referred to using a filename. It takes the form of

<(list)

or

>(list)

The process list is run asynchronously, and its input or output appears as a filename. This filename is passed as an argument to the current command as the result of the expansion. If the >(list) form is used, writing to the file will provide input for list. If the <(list) form is used, the file passed as an argument should be read to obtain the output of list. Note that no space may appear between the < or > and the left parenthesis, otherwise the construct would be interpreted as a redirection. Process substitution is supported on systems that support named pipes (FIFOs) or the /dev/fd method of naming open files.

When available, process substitution is performed simultaneously with parameter and variable expansion, command substitution, and arithmetic expansion.