You can copy the first string to the clipboard, then highlight the
second string and press Shift+Cmd+C.

However, as with Marcel's solution, I don't believe this provides in-line diffs.

On Tue, Aug 17, 2021 at 2:48 AM gettimothy via Squeak-dev
<squeak-dev at lists.squeakfoundation.org> wrote:
>
> Hi Folks,
>
> I did not find what I was looking for on forum world, so asking here.
>
> I would like to "diff" to strings
>
> "Lazy fat dog" diff: "Lazy fat cat"
>
> I took a brief glance at the Diff3 class and tests and saw nothing obvious, so I ask here.
>
> Thank you for your time
>
>