尽管这是一个老问题，但我在获取动态变量名时仍然遇到了一些困难，同时避免使用eval (evil)命令。

用declare -n解决了这个问题，它创建了一个动态值的引用，这在CI/CD进程中特别有用，其中CI/CD服务所需的秘密名称直到运行时才知道。方法如下:

# Bash v4.3+
# -----------------------------------------------------------
# Secerts in CI/CD service, injected as environment variables
# AWS_ACCESS_KEY_ID_DEV, AWS_SECRET_ACCESS_KEY_DEV
# AWS_ACCESS_KEY_ID_STG, AWS_SECRET_ACCESS_KEY_STG
# -----------------------------------------------------------
# Environment variables injected by CI/CD service
# BRANCH_NAME="DEV"
# -----------------------------------------------------------
declare -n _AWS_ACCESS_KEY_ID_REF=AWS_ACCESS_KEY_ID_${BRANCH_NAME}
declare -n _AWS_SECRET_ACCESS_KEY_REF=AWS_SECRET_ACCESS_KEY_${BRANCH_NAME}

export AWS_ACCESS_KEY_ID=${_AWS_ACCESS_KEY_ID_REF}
export AWS_SECRET_ACCESS_KEY=${_AWS_SECRET_ACCESS_KEY_REF}

echo $AWS_ACCESS_KEY_ID $AWS_SECRET_ACCESS_KEY
aws s3 ls

虽然我认为声明-n仍然是最好的方法，但还有另一种没有人提到的方法，在CI/CD中非常有用

function dynamic(){
  export a_$1="bla"
}

dynamic 2
echo $a_2

此函数不支持空格，因此动态“2 3”将返回错误。

我希望能够创建一个包含该命令的第一个参数的变量名

script.sh文件:

#!/usr/bin/env bash
function grep_search() {
  eval $1=$(ls | tail -1)
}

测试:

$ source script.sh
$ grep_search open_box
$ echo $open_box
script.sh

根据帮助评估:

作为shell命令执行参数。

你也可以使用Bash ${!间接展开，正如前面提到的，但是它不支持检索数组下标。

欲进一步阅读或示例，请查看BashFAQ/006关于Indirection的内容。

我们不知道有任何技巧可以在POSIX或Bourne shell中复制该功能，而不需要eval，这可能很难安全地做到。所以，考虑这是一个自担风险的使用黑客。

但是，您应该根据以下注意事项重新考虑使用间接方法。

Normally, in bash scripting, you won't need indirect references at all. Generally, people look at this for a solution when they don't understand or know about Bash Arrays or haven't fully considered other Bash features such as functions. Putting variable names or any other bash syntax inside parameters is frequently done incorrectly and in inappropriate situations to solve problems that have better solutions. It violates the separation between code and data, and as such puts you on a slippery slope toward bugs and security issues. Indirection can make your code less transparent and harder to follow.

尽管这是一个老问题，但我在获取动态变量名时仍然遇到了一些困难，同时避免使用eval (evil)命令。

用declare -n解决了这个问题，它创建了一个动态值的引用，这在CI/CD进程中特别有用，其中CI/CD服务所需的秘密名称直到运行时才知道。方法如下:

# Bash v4.3+
# -----------------------------------------------------------
# Secerts in CI/CD service, injected as environment variables
# AWS_ACCESS_KEY_ID_DEV, AWS_SECRET_ACCESS_KEY_DEV
# AWS_ACCESS_KEY_ID_STG, AWS_SECRET_ACCESS_KEY_STG
# -----------------------------------------------------------
# Environment variables injected by CI/CD service
# BRANCH_NAME="DEV"
# -----------------------------------------------------------
declare -n _AWS_ACCESS_KEY_ID_REF=AWS_ACCESS_KEY_ID_${BRANCH_NAME}
declare -n _AWS_SECRET_ACCESS_KEY_REF=AWS_SECRET_ACCESS_KEY_${BRANCH_NAME}

export AWS_ACCESS_KEY_ID=${_AWS_ACCESS_KEY_ID_REF}
export AWS_SECRET_ACCESS_KEY=${_AWS_SECRET_ACCESS_KEY_REF}

echo $AWS_ACCESS_KEY_ID $AWS_SECRET_ACCESS_KEY
aws s3 ls

我最近一直在寻找更好的方法。联想数组对我来说太夸张了。看看我发现了什么

suffix=bzz
declare prefix_$suffix=mystr

.．.然后……

varname=prefix_$suffix
echo ${!varname}

从文档中可以看出:

The ‘$’ character introduces parameter expansion, command substitution, or arithmetic expansion. ... The basic form of parameter expansion is ${parameter}. The value of parameter is substituted. ... If the first character of parameter is an exclamation point (!), and parameter is not a nameref, it introduces a level of indirection. Bash uses the value formed by expanding the rest of parameter as the new parameter; this is then expanded and that value is used in the rest of the expansion, rather than the expansion of the original parameter. This is known as indirect expansion. The value is subject to tilde expansion, parameter expansion, command substitution, and arithmetic expansion. ...

将两个评分较高的答案结合成一个完整的例子，希望有用且不言自明:

#!/bin/bash

intro="You know what,"
pet1="cat"
pet2="chicken"
pet3="cow"
pet4="dog"
pet5="pig"

# Setting and reading dynamic variables
for i in {1..5}; do
        pet="pet$i"
        declare "sentence$i=$intro I have a pet ${!pet} at home"
done

# Just reading dynamic variables
for i in {1..5}; do
        sentence="sentence$i"
        echo "${!sentence}"
done

echo
echo "Again, but reading regular variables:"
echo $sentence1
echo $sentence2
echo $sentence3
echo $sentence4
echo $sentence5

输出:

你知道吗，我家里有一只宠物猫 你知道吗，我家里有只宠物鸡 你知道吗，我家里有一头宠物牛 你知道吗，我家里有一只宠物狗 你知道吗，我家里有只宠物猪

同样，但是读取的是常规变量: 你知道吗，我家里有一只宠物猫 你知道吗，我家里有只宠物鸡 你知道吗，我家里有一头宠物牛 你知道吗，我家里有一只宠物狗 你知道吗，我家里有只宠物猪