如何prevent文件名扩展为在bash循环 [英] How to prevent filename expansion in for loop in bash

问题描述

在一个像这样的循环，

for i in `cat *.input`; do
    echo "$i"
done

如果输入文件之一，包含像项* A ，会，并给
文件名中的'A'的结局。

if one of the input file contains entries like *a, it will, and give the filenames ending in 'a'.

有$ P $的pventing这个文件名扩展一个简单的方法？

Is there a simple way of preventing this filename expansion?

由于使用多个文件，通配符（设置-o noglob ）不是
好的选择。我也应该能够猫的输出滤波器来
特殊字符转义，而

Because of use of multiple files, globbing (set -o noglob) is not a good option. I should also be able to filter the output of cat to escape special characters, but

for i in `cat *.input | sed 's/*/\\*'`
    ...

还是引起了 *一个扩大，而

for i in `cat *.input | sed 's/*/\\\\*'`
    ...

给我 \\ *一个（包括反斜杠）。 [我想这是一个不同的
虽然问题]

gives me \*a (including backslash). [ I guess this is a different question though ]

推荐答案

这将猫所有文件的内容的和迭代结果行：

This will cat the contents of all the files and iterate over the lines of the result:

while read -r i
do
    echo "$i"
done < <(cat *.input)

如果文件的包含的的通配符，他们将不会扩大。这些键是不使用为并引用您的变量。

If the files contain globbing characters, they won't be expanded. They keys are to not use for and to quote your variable.

在不支持进程替换伯恩衍生弹，这相当于：

In Bourne-derived shells that do not support process substitution, this is equivalent:

cat *.input | while read -r i
do
    echo "$i"
done

的理由不这样做，在Bash是它创建一个子shell，当子shell（环）出口，内设置任何 CD 目录更改变量的值将丢失。

The reason not to do that in Bash is that it creates a subshell and when the subshell (loop) exits, the values of variables set within and any cd directory changes will be lost.

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