Search operators

Operators turn a search box into a filter over a crawled index. The cost is that you are querying somebody's index, not the web — coverage, freshness and operator fidelity vary enormously between engines. The mistake beginners make is assuming their query ran as typed. Google routinely drops, stems, and synonym-expands your terms, so a zero-result dork and a silently-rewritten dork look nothing alike but are equally useless.

Which engine for which job