bash *导出*所有变量从键=值文件到shell
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*export* all variables from key=value file to shell
提问by uml?ute
If I want to inherit environment variables to child processes, i do something like:
如果我想将环境变量继承给子进程，我会执行以下操作：
export MYVAR=tork
Assume I have a a file site.confcontaining assignments of values (that can contain spaces) to variables:
假设我有一个文件，site.conf其中包含对变量的值（可以包含空格）的赋值：
EMAIL="[email protected]"
FULLNAME="Master Yedi"
FOO=bar
Now I would like to process this file whenever I open a new shell (e.g. with some code in ~/.bashrcor ~/.profile), so that any processes started from within that newly opened shell will inherit the assignments via environmental variables.
现在，每当我打开一个新的 shell（例如在~/.bashrc或 中使用一些代码~/.profile）时，我都想处理这个文件，以便从新打开的 shell 中启动的任何进程都将通过环境变量继承分配。
The obvious solution would be to prefix each line in site.confwith an exportand just source the file. However I cannot do this since the file is also read (directly) by some other applications, so the format is fixed.
显而易见的解决方案是在每一行前面site.conf加上一个前缀，export并且只提供文件的来源。但是我不能这样做，因为文件也被其他一些应用程序（直接）读取，所以格式是固定的。
I tried something like
我试过类似的东西
cat site.conf | while read assignment
do
export "${assignment}"
done
But this doesn't work, for various reasons (the most important being that exportis executed in a subshell, so the variable will never be exported to the children of the calling shell).
但这不起作用，出于各种原因（最重要的export是在子 shell 中执行，因此变量永远不会导出到调用 shell 的子级）。
Is there a way to programmatically exportunknown variables in bash?
有没有办法export在bash中以编程方式未知变量？
回答by chepner
Run set -abefore sourcing the file. This marks all new and modified variables that follow for export automatically.
set -a在获取文件之前运行。这会标记所有新的和修改后的变量，以便自动导出。
set -a
source site.conf
set +a # Require export again, if desired.
The problem you observed is that the pipe executes the exportin a subshell. You can avoid that simply by using input redirection instead of a pipe.
您观察到的问题是管道export在子外壳中执行。您可以简单地通过使用输入重定向而不是管道来避免这种情况。
while read assignment; do
export "$assignment"
done < site.conf
This won't work, however, if (unlikely though it is) you have multiple assignments on one line, such as
但是，如果（虽然不太可能）您在一行上有多个分配，则这将不起作用，例如
EMAIL="[email protected]" FULLNAME="Master Yedi"
回答by anubhava
Problem is cat site.conf | while read assignmentusing pipes.
问题是cat site.conf | while read assignment使用管道。
Pipes create a sub-shell, hence the variable created using exportget created in a sub-shell and are not available in your current shell.
管道创建一个子外壳，因此使用exportget 创建的变量在子外壳中创建，并且在您当前的外壳中不可用。
You can just do:
你可以这样做：
source $HOME/site.conf
from your ~/.bashrcto export all the variables and make them available in shell.
从您~/.bashrc导出所有变量并使它们在 shell 中可用。
