在shell脚本中使用只读变量 [英] Use of read-only variables in shell scripts

问题描述

这是好壳的编程习惯使用只读变量只要有可能还是有什么缺点？例如。如果我想要写一些脚本，由多个脚本文件使用的不可变的文件路径，这将是有意义的声明这样的路径：

Is it good shell programming practice to use read-only variables whenever possible or does it have any drawbacks? E.g. if I wanted to write some script that consists of multiple script files that make use of immutable file paths, would it make sense to declare the paths like that:

readonly LOGS
export LOGS 
LOGS="/some/path"

另一个问题：这是个好主意分裂单片和过于繁琐的阅读shell脚本code到单独的文件？
非常感谢您的回答。

Another question: Is it a good idea to split monolithic and tedious too read shell script code into separate files? Many thanks for your answers.

推荐答案

这听起来像你可能会认为只读不超过它确实。一方面，只读状态不会导出到环境或由子进程继承：

It sounds like you might think that readonly does more than it really does. For one thing, readonly status is not exported into the environment or inherited by child processes:

$ declare -rx LOGS=hello
$ LOGS=goodbye
bash: LOGS: readonly variable
$ bash -c 'echo "$LOGS"'
hello
$ bash -c 'LOGS=goodbye; echo "$LOGS"'
goodbye
$ 

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