Search your Firefox bookmarks, history and tabs from the address bar

available in : Firefox 4 (SeaMonkey 2.1) and later. Better support in Firefox 48 with multi process.

If you are looking for a specific type of result, like a bookmark or tag, you can speed up or restrict the process of finding it by typing in special characters after or before each search term in the location bar separated by spaces:

• Add ^ to search for matches in your browsing history.
• Add * to search for matches in your bookmarks.
• Add + to search for matches in pages you've tagged.
• Add % to search for matches in your currently open tabs.
• Add ~ to search for matches in pages you've typed.
• Add # to search for matches in page titles.
• Add @ to search for matches in web addresses (URLs).
• Add $ to search for matches in suggestions.
• Add ? to search keyword to search using default search engine.

For example, if you're looking for a page you bookmarked called Mozilla Firefox Support, you might type mozilla. The autocomplete results appear, but might not show the page you want.

You can narrow your results down to bookmarks only by making your search string mozilla  *.

If you still have too many results, you can further restrict the search by making your search string mozilla  *  support  #. Now the autocomplete list will only show bookmarked pages with mozilla and support in the page title.

Notes:

• When you see the page you want, just click on it or use the up and down arrows on your keyboard to highlight it and then press Enter.
• Press the ALT key while clicking or press Enter on the page in the autocomplete list that appears below your address bar. This will open your page in a new tab instead of switching to an existing one.
• Press the CTRL key while clicking on the page in the autocomplete list that appears below your address bar. This will open your page in a new tab instead of switching to an existing one.
• Press the SHIFT key while clicking on the page in the autocomplete list that appears below your address bar. This will open your page in a new window instead of switching to an existing one.

How to turn on awesome bar / Troubleshooting

• Using Location Bar Options
1. Search Engine suggestion
1. Load about:preferences#search in the browser's address bar and hit enter.
2. You define the default search engine that Firefox uses when you type in the location bar.
3. In addition to selecting a different engine from the list, you may also define whether the search engine is allowed to provide search suggestions, and to display those suggestions in location bar results.
4. If you don't find your favorite search engine listed by the selection menu, use Mozilla addon search engine to find it.
2. Whatever you have done inside Firefox browser
1. Load about:preferences#privacy in the browser's address bar and hit enter.Scroll down until the Location Bar section is displayed. You may use it to select which suggestions Firefox should display when you type in the location bar.
2. It will suggest history, bookmarks and open tabs by default, but you can uncheck any item here to block those suggestions.
• Location Bar preferences (about:config)
  The following preferences are only accessible via about:config and not the Firefox options. You can reset any of those you may have changed to their default value with a right-click and the selection of reset.
1. Load about:config in the Firefox address bar and hit enter.
2. If you have never been there, confirm the prompt that appears.
3. Change the value of a preference, double-click on it. If it is a Boolean (True or False, it will change its state to the other), while a field is displayed for all other data types.
4. Type, or copy and paste, the following preferences to change their values.
   browser.urlbar.autoFill - true.
   browser.urlbar.autoFill.typed - true.
   browser.urlbar.maxRichResults - Change the number of suggestions displayed from 12 to another value. Increase limit, if you want it and default is 12.
   browser.urlbar.unifiedcomplete - If you set it to false, Firefox will no longer show "visit" or "search with" suggestions in the location bar.
   keyword.enabled - true.
   browser.urlbar.match.title     #    Returns results that match the text in the title.
   browser.urlbar.match.url     @    Returns results that match the text in the URL.
   browser.urlbar.restrict.bookmark     *    Returns only results that are from the bookmarks.
   browser.urlbar.restrict.history     ^    Returns only results that are from the browser’s history.
   browser.urlbar.restrict.tag     +    Returns only results that have been tagged.
   browser.urlbar.restrict.typed     ~    Returns only results that have been typed.
   browser.urlbar.restrict.openpage     %     Returns only open tabs (visible tabs, not active tab).
• Using Search box
• Click the Search icon placed at the left top of Firefox Awesome bar and select “Manage Search Engines”.
• In the next window, deselect the checkbox “Show Search suggestions” and press Ok. You are done.

reference:
support.mozilla.org
ghacks.net
maketecheasier.com