A comparison between public-domain search engines

The enormous amount of information available today on the Internet requires the use of search tools such as search engines, meta-search engines and directories for rapid retrieval of useful and appropriate information. Indexing a website?s content by search engine allows its information to be located quickly and improves the site?s usability. In the case of a large number of pages distributed over different systems (e.g. an organization with several autonomous branches/departments) a local search engine rapidly provides a comprehensive overview of all information and services offered. Local indexing generally has fewer requirements than global indexing (i.e. resources, performance, code optimization), thus public-domain SW can be used effectively. In this paper, we compare four open-source search engines available in the Unix environment in order to evaluate their features and effectiveness, and to understand any problems that may arise in an operative environment.