Permanently revealing Library directory ...



I have a backup drive of my previous MacBook Pro which includes the user Library directory. However, when I go to access this directory it is, understandably, invisible since Apple restricts access to the User Library directory. I know there are ways to reveal the User Library directory on the current user's Mac, but I need a way to permanently reveal this directory on the backup drive of my previous MacBook.

There must be a UNIX command which can accomplish this ...

Thanks for any assistance you can offer.

I think since High Sierra, maybe Sierra, you can simply type Shift-Command-. (period), which will show all hidden files and folders.
Type same Shift-Command-. to toggle hidden files back into hiding.
I know, that doesn't really answer your question about having the library displayed regardless of the system that you might use to view it.
but, you can also use the Go to Folder... (Shift-Command-g), type in the path to the hidden library folder (such as: /volume/"volume name"/Users/"username"/Library -- which will bring up that Library folder you need to access.

You may find a better method to do that, such as manually changing the user library to be visible, but that may change if you plug in to another system that doesn't respect the "unhide" command through the terminal, so you might need to mess with that each time you connect to a different Mac.
That's one reason why I don't try a master command, and just browse to the folder through that "Go To Folder" command in the Finder. It's just a method that I usually use, and it works for me.
Maybe someone else will respond with a better way to do that...
Are you wishing to 'browse' that library, or you looking for a specific file?
If specific, I would use EasyFind to bring it up to read, duplicate, or copy.