This used to work by default in previous versions of FF.
now they don’t.
My personal favorite was
sadly that’s gone too.
Here’s how to fix it…
Open about:config and search for keyword.URL - it should be blank.
Double-click to edit and enter
withOUT the quotes. (This is the code at Google to press the I’m Feeling Lucky button)
This will restore the previous Firefox keyword search behavior.
No restart necessary.