[How to] Change default search engine in Iceweasel (Firefox)

Type in the URL bar ‘about:config‘ and search for ‘keyword.url‘ and modify the ‘Value‘ from

http://www.google.com/search?ie=UTF-8&oe=UTF-8&sourceid=navclient&gfns=1&q=

to your preferred search engine, for me I changed it to Duck Duck Go

https://duckduckgo.com/?q=

You can find a full list of available parameters here to have a more custom search string

https://duckduckgo.com/?kl=au-en&kp=-1&q=

Now all there is left to do is restart Iceweasel (Firefox) and enjoy the new default search engine you can use from the URL bar