sed中的環境變量替換 - Environment variable substitution in sed

問題：

If I run these commands from a script:如果我從腳本運行這些命令：

#my.sh
PWD=bla
sed 's/xxx/'$PWD'/'
...
$ ./my.sh
xxx
bla

it is fine.沒事。

But, if I run:但是，如果我運行：

#my.sh
sed 's/xxx/'$PWD'/'
...
$ ./my.sh
$ sed: -e expression #1, char 8: Unknown option to `s' 

I read in tutorials that to substitute environment variables from shell you need to stop, and 'out quote' the $varname part so that it is not substituted directly, which is what I did, and which works only if the variable is defined immediately before.我在教程中讀到，要從 shell 替換環境變量，您需要停止，並“引用” $varname部分，以便它不會被直接替換，這就是我所做的，並且僅當變量在之前定義時纔有效.

How can I get sed to recognize a $var as an environment variable as it is defined in the shell?我怎樣才能讓 sed 將$var識別爲 shell 中定義的環境變量？

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解決方案：

參考一： https://stackoom.com/question/2S9m
參考二： Environment variable substitution in sed