On of the first things I do when first using a fresh Firefox profile, is to set browser.urlbar.trimURLs to false (which really should be changeable though ‘Preferences’ or should have remained default), and to change the search and homepage defaults to DuckDuckGo. Currently I manually go to about:config, click through the angry warning message, and search for the keys (which unlike in DConf Editor, aren't even organised).

So I would like to know how to read and write these keys from the command-line so that I can add these tweaks to my customisations script.