GNU grep is based on a fast lazy-state deterministic matcher (about twice as fast as stock Unix egrep) hybridized with a Boyer-Moore-Gosper search for a fixed string that eliminates impossible text from being considered by the full regexp matcher without necessarily having to look at every character. The result is typically many times faster than Unix grep or egrep.
Debian package information is generally stored in files having a special file format, dubbed the Debian control file format (dctrl), a special case of the record jar file format. These tools operate on any files conforming in a general sense to that format, and are therefore widely applicable whenever this format is in play. The tools in this bundle are grep-dctrl, sort-dctrl, join-dctrl, and tbl-dctrl.
integrit is an alternative to file integrity verification programs like tripwire and aide. It helps you determine whether an intruder has modified a computer system. integrit's major advantages are a small memory footprint and simplicity. It works by creating a database that is a snapshot of the most essential parts of your computer system. You put the database somewhere safe, and you can then use it to make sure that no one has made any illicit modifications to the computer system. In the case of a break in, you know exactly which files have been modified, added, or removed.