Lucene defines a term as a single word. Entering multiple terms in the search box will retrieve documents which contain at least one of the terms. For example, oracle calendar will search for documents with either oracle or calendar . A phrase , however, consists of multiple terms surrounded by quotes. For a document to match, it must contain the phrase, exactly as entered in the search box. So, in contrast to the previous example, "oracle calendar" (note the quotation marks) will only return those documents which contain the phrase oracle calendar .

Unless otherwise specified, terms and phrases are searched for throughout the entire document. Lucene supports field specific searches if you need to narrow your search down to a specific part of the document, such as the document's title. To search for a term or phrase in a specific field, enter the field name, a colon and your search term or phrase. For example, title:"windows xp" will only match documents with the phrase windows xp appearing in the title. The following fields are available for searching on help.unc.edu:

Lucene recognizes the Boolean operators AND , OR and NOT . Please note, Boolean operators must be capitalized in order to be recognized as Boolean operators.

The wildcard characters * and ? are also available for use in Lucene. The * wildcard matches multiple characters and the ? wildcard matches a single character. For example, network* would match network , networks or networking , whereas the search term network? would only match networks. (Why doesn't network? match network , you might ask? The ? wildcard matches only one character, not zero characters. Perhaps a more useful application of the ? wildcard is for capturing variant spellings, e.g. gr?y .) Wildcard characters can be placed in the middle of words, too, but you cannot put a wildcard character at the beginning of a word.

Parenthesis can be used to group multiple search terms into logical groups. They are often a good idea if you are combining multiple terms with different Boolean operators, as the results will be easier to predict. For example, the search photoshop AND (tutorial OR howto) will return documents containing the word photoshop and either tutorial or howto .