With so many packages available, it can be hard to find the exact thing you need using command-line APT. The general search tool is called
apt-cache and is used like this:
matthew@seymour:~$ apt-cache search kde
Depending on which repositories you have enabled, that tool returns about a thousand packages. Many of those results will not even have KDE in the package name but will be matched because the description contains the word KDE.
You can filter through this information in several ways. First, you can instruct
apt-cache to search only in the package names, not in their descriptions. You do this with the
–n parameter, like this:
matthew@seymour:~$ apt-cache –n search ...