I recently installed Ubuntu 20.04 LTS (Focal Fossa) (dated 23 April 2020), with the intention of creating a VM using VirtualBox 6.0.22 (released 15 May 2020). I had issues with VirtualBox guest additions, and this is how I solved it.
On my MacBook Pro with retina display, when I take a screenshot, the image is saved with a DPI of 144. But, using ImageOptim to compress the image with Strip JPEG/PNG Metadata enabled will remove (or reset) the DPI setting to 72 DPI - resulting in a double sized image when displayed in Preview and Quick Look. Here is how I correct this.
From macOS Catalina 10.5 onwards,
zsh is the default shell, instead of
bash. I have a lot to learn about this shell, and so far, this is how I configured zsh... There is an overload of snippets on-line, but I’ve not seen a post doing what I do, so hopefully this helps someone!