如何将文件逐行传送到多个读取变量中? [英] How do I pipe a file line by line into multiple read variables?

问题描述

我有一个包含两列信息的文件:

I have a file that contains information in two columns:

box1 a1
box2 a2

我正在尝试将此文件逐行读取到read中，并将每个订单项都放入一个变量中.

I'm trying to read this file line by line into read and have each line items be put into a variable.

在第一遍中，$a将包含box1，而$b将包含a1.

On the first pass, $a would contain box1 and $b would contain a1.

在第二遍中，$a将包含box2，而$b将包含a2，依此类推.

On the second pass, $a would contain box2 and $b would contain a2, etc.

我要尝试实现的代码示例如下:

An example of the code that I am using to try to achieve is this:

for i in text.txt; do
    while read line; do
        echo $line | read a b;
    done < text.txt;
    echo $a $b;
done

这给了我以下结果:

box1 a1 box2 a2

当我期望以下结果时:

box1 a1
box2 a1

我该如何解决?

推荐答案

输入read命令会使变量在子shell中进行设置，这使得其余部分无法访问(实际上，它们已消失)代码.但是，在这种情况下，您甚至不需要for循环或第二个read命令:

Piping into a read command causes the variables to be set in a subshell, which makes them inaccessible (indeed, they are gone) to the rest of your code. In this case, though, you don't even need the for loop or the second read command:

while read -r a b; do
    echo "$a" "$b"
done < text.txt

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