lookbib(1), lkbib(1) and indexbib(1) man pages.
For searching in a database, two programs exist, lookbib(1) and lkbib(1). For a faster response time using these two programs, use indexbib(1) to create an index.
The lookbib program is more aimed at a interactive use. It prints a prompt for you to input a search string and returns the matching results. Whereas the lkbib program is not interactive and the search string is to be given as a command line argument.