Your first snippet should work fine:
var text = $LineEdit.text
Or, at least, that'll store the text contents of a child
LineEdit control in a local variable named
I assume the problem might be in the use it in another scene part of your question. With the above code, the
text variable (along with its value) will disappear when the scene is changed. If that's the problem, the simplest solution is to create a separate, singleton script that you can store this value (and any other global values in). Such variables will retain their values regardless of scene changes.
So, create a new script (say,
Globals.gd), and add your variable to it:
Make the script an autoloaded singleton via
Project | Project Settings | Autoload. Just select your new
Globals.gd script and add it to the list.
Next, store your
LineEdit value in the global script like:
Globals.line_edit_text = $LineEdit.text
Then, in any other scene (as needed), retrieve the value from the same global variable...