apt search for packages on Ubuntu / Debian

Sure there's a gui for doing this, but sometimes you're adminitering or working on a Debian/Ubuntu box and you need to figure out the package name for that software package you need.

The command is

apt-get search

Useful options are:

--installed
--names-only

The first option searches only the installed packages. The default is to search both installed and non-installed packages.
The second option searchs only the names. The default is to search the name and description.