While Google is a great search engine, you've probably noticed that when you do a search, Google usually returns more results that you can comfortably chew. But how can you limit Google's search results?

Using Booleans

Booleans are simply expression that Google (or a text processor) expects to be either true or false. When performing a Google search, booleans can be your friend.

Every time you do a search, Google assumes that you want to find all of the words or terms in your query. For example, typing tips Linux “Windows Vista” is the same as typing the Boolean tips AND Linux AND “Windows Vista”.  Google will search for Web sites that contain any combination of the words tips, Linux, and Windows Vista.

But what if you only want to find sites containing tips for Linux or tips for Windows Vista? Just type tips OR Linux OR “Windows Vista”. You can further focus the search by surrounding some of the options in parentheses. So, typing tips (Linux OR “Windows Vista”) is the same as typing tips AND Linux or  tips AND “Windows Vista”.

Searching Files

The language of the Web is HTML. A Web page is just a text file that contains formatting which tells a Web browser how to display the elements on a page.

But people don't just post HTML pages to the Web. They also post Word documents, spreadsheets, slides, and PDFs. Often, these files are packed with information that you won't find anywhere else on the Web. You can get Google to zoom in on those files using the filetype: command. Google can actually search within the contents of the following file types:

• doc (Word documents)
• xls (Excel spreadsheets)
• ppt (PowerPoint presentations)
• pdf (PDF files)
• odt (OpenDocument files)
• ps (Postscript files)
• rtf (Rich Text File documents)
• sfw (Flash multimedia files)
• txt (plain text files)

You can also use Google to search such older or seldom-used formats as Lotus 1-2-3 spreadsheets, Microsoft Words files, and MacWrite documents.

So, if you want to search for information on building a PC from scratch that may reside in a PDF file somewhere on the Web, type “build a PC” filetype:pdf in the Google search box. You can either download the documents that the search returns, or click the View as HTML link beside a result to view the document in your browser.