使用bash从ubuntu上的文件中读取带有未转义字符的环境变量

本文介绍了使用bash从ubuntu上的文件中读取带有未转义字符的环境变量的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

限时送ChatGPT账号..

如何在 bash 中读取包含空格和可能需要转义的其他字符的环境变量?

How to read environmental variable in bash that contains spaces and possibly other characters that need to be escaped?

我有一个文件 server.env

I have a file server.env

PUBLIC_KEY=ssh-rsa whatever+whatever+8whatever/whatever+p+whatever user@alans-MacBook-Pro.local

我正在尝试将此文件作为环境变量读入 bash 脚本:

I am trying to read this file into bash script as an environmental variable:

export $(cat server.env | xargs)

我收到一个错误:

-bash: export: `user@alans-MacBook-Pro.local': not a valid identifier

好的，尝试引用 server.env 中的值:

OK, trying to quote the value in server.env:

PUBLIC_KEY='ssh-rsa whatever+whatever+8whatever/whatever+p+whatever user@alans-MacBook-Pro.local'

同样的错误

双引号:

PUBLIC_KEY="ssh-rsa whatever+whatever+8whatever/whatever+p+whatever user@alans-MacBook-Pro.local"

还有错误

我在这里遗漏了什么?

推荐答案

Bash 提供了参数扩展和子字符串删除，这将允许您分离读取的 NAME=value 对从 server.env 文件，然后 export NAME=value 对.

Bash provides parameter expansion with substring removal that will allow you to separate the NAME=value pairs read from the server.env file and then export the NAME=value pairs.

您只需要一个简单的读取循环:

A simple read loop is all you need:

#!/bin/bash

while read -r line; do              ## read each line of server.env
    val="${line#*=}"                ## trim to 1st =, save in val
    export ${line%=$val}="$val"     ## remove =$val leaving name, export val with name
done < server.env

printf "%s\n" "$PUBLIC_KEY"         ## confirm

示例使用/输出

$ bash test.sh
ssh-rsa whatever+whatever+8whatever/whatever+p+whatever user@alans-MacBook-Pro.local

基本的参数扩展在哪里:

${var#pattern}      Strip shortest match of pattern from front of $var
${var##pattern}     Strip longest match of pattern from front of $var
${var%pattern}      Strip shortest match of pattern from back of $var
${var%%pattern}     Strip longest match of pattern from back of $var

(注意: pattern 可以包含普通的 shell glob，如 '*' 和 '?')

(note: pattern can contain normal shell globs like '*' and '?')

实际上有许多有用的参数扩展可用于字符串操作.只需检查 参数扩展" 标题下的 man bash.

There are literally dozens of useful parameter expansions you can use for string manipulations. Just check man bash under the "Parameter Expansion" heading.

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