在sed中使用一个命令的输出作为替换文本(Use output of one command as replacement text in sed)

 我有一个.env文件，有一堆键值对，如下所示： 
 
NAME=John Doe
CITY=Timbuctoo
CSS=<some value>
PORT=3000
 
 这是我尝试以编程方式更改的第三行。 是一个动态生成的md5散列，每次运行该命令时，都需要用新的散列代替。 这就是我生成哈希的方式： 
 
$ date +%s | md5sum | cut -d' ' -f 1
 
 我希望在使用sed时使用上述命令的输出作为替换文本。 但无法弄清楚如何使其工作。 以下是我迄今为止所完成的解决方案： 
 
$ date +%s | md5sum | cut -d' ' -f 1 | sed -i.bak 's/^\(CSS=\).*/replacement/' ~/nano/.env
 
 什么应该代替“替换”来确保原始值被cut返回的值所取代？ 

I have a .env file with a bunch of key-value pairs like so:
 
NAME=John Doe
CITY=Timbuctoo
CSS=<some value>
PORT=3000
 
It is the third line I'm trying to change programmatically. is a dynamically-generated md5 hash and each time I run the command, it needs to be replaced by a new hash. This is how I'm generating the hash:
 
$ date +%s | md5sum | cut -d' ' -f 1
 
And I wish to use the output of the above command as the replacement text when using sed. But can't figure out how to make it work. The following is the solution I have so far which is far from complete:
 
$ date +%s | md5sum | cut -d' ' -f 1 | sed -i.bak 's/^\(CSS=\).*/replacement/' ~/nano/.env
 
What should put in place of "replacement" to ensure the original value gets replaced by the value returned by cut?

原文：https://stackoverflow.com/questions/45484115