The KTMS Search Engine is an adaptation of the htgrep search engine written by Oscar Nierstrasz of the University of Berne (Switzerland). It is written in Perl (Practical Extraction and Reporting Language -- Larry Wall's ubiquitous scripting language). The following information is excerpted from the htgrep online documentation.
To find parts of words, use an asterisk (*) to represent missing parts of the word. For example, if you enter "world*" it will match "worldwide", "worlds", etc. Similarly, "*world" would find "underworld", etc.
If instead of the word or you entered and it would match only records which contained both the word "apple" and the word "orange". Note that this would be the same as a simple search for "apple orange" because if the boolean commands are omitted, it defaults to assuming an and between each search word.
To find records which do not contain a particular word, place the word not before it. For example, "not blue" would find all the records which do not contain the word "blue". You can combine the "and", "or" and "not" commands, for example "apple and not red" would find records containing the word apple but not the word red.
For advanced use, you can use brackets to group the expression. For example, "apple and (red or green)" would find all records containing the word "apple" and either "red" or "green" (or both). If the brackets are omitted, the and command has higher precedence, so "apple and red or green" would find all records contain "apple" and "red", and also records containing "green".