在shell脚本中获取命令标准输出的fd文件名的可移植方法

Question

我很确定我在这方面缺少术语，这可能是谷歌让我失望的原因。是否有一种可移植且简单的方法将标准输出重定向到多个命令?

换句话说，我如何解决这个可移植性问题:

$ /bin/bash -c '(echo to your mom) | tee >(read b; echo "agent 1 reports $b") >(read b; echo "agent 2 reports $b")  >(read b; echo "agent 3 reports $b")'
to your mom
agent 1 reports to your mom
agent 2 reports to your mom
agent 3 reports to your mom
$ /bin/zsh -c '(echo to your mom) | tee >(read b; echo "agent 1 reports $b") >(read b; echo "agent 2 reports $b")  >(read b; echo "agent 3 reports $b")'
to your mom
agent 1 reports to your mom
agent 3 reports to your mom
agent 2 reports to your mom
$ /bin/sh -c '(echo to your mom) | tee >(read b; echo "agent 1 reports $b") >(read b; echo "agent 2 reports $b")  >(read b; echo "agent 3 reports $b")'
/bin/sh: 1: Syntax error: "(" unexpected

请注意，输出顺序不是问题，/bin/sh产生错误才是问题。

Answer 1

使用命名管道:

#!/bin/sh
fifo1=$(exec mktemp --dry-run)
mkfifo "$fifo1"
( read b; echo "agent 1 reports $b" ) < "$fifo1" &
fifo2=$(exec mktemp --dry-run)
mkfifo "$fifo2"
( read b; echo "agent 2 reports $b" ) < "$fifo2" &
fifo3=$(exec mktemp --dry-run)
mkfifo "$fifo3"
( read b; echo "agent 3 reports $b" ) < "$fifo3" &
echo to your mom | tee "$fifo1" "$fifo2" "$fifo3"
rm -f "$fifo1" "$fifo2" "$fifo3"

用法:

sh script.sh

输出:

to your mom
agent 2 reports to your mom
agent 1 reports to your mom
agent 3 reports to your mom

这就是科学。通过函数，您可以根据您的喜好使技术使管道更容易。