The recoll program provides the user interface for searching. It is based on the QT library.
Start the recoll program.
Enter search term(s) in the text field at the top of the window.
Click the Search button or hit the Enter key to start the search.
By default, this will look for documents with any of the search terms (the ones with more terms will get better scores). You can check the All terms checkbox to ensure that only documents with all the terms will be returned. Use the Tools / Advanced search dialog for more complex searches.
After starting a search, a list of results will instantly be displayed in the main list window. Clicking on an entry will open an internal preview window for the document. Double-clicking will attempt to start an external viewer (have a look at the ~/.recoll/mimeconf file to see how these are configured).
By default, the document list is presented in order of relevance (how well the system estimates that the document matches the query). You can specify a different ordering by using the Tools / Sort parameters dialog.
You can click on the first paragraph (Query results or No results found) in the result list to get an exact display of the query actually performed, after stem expansion and other processing.