Ubuntu 20.04: move window buttons to left / right

Problem

You want to move the window buttons (e.g. Close) to the left / right. How to do that?

Solution

I found a short video about it here (length: 45 sec).

To sum up: launch the app Tweaks, then Window Titlebars -> Placement.

[mongodb] move docs from one collection to another one

var documentsToMove = db.collectionA.find({});
documentsToMove.forEach(function(doc) { 
    db.collectionB.insertOne(doc); 
    db.collectionA.remove(doc);
});

Tip from here.