Pre-built, or “binary” packages are the easiest and most common way to install aptitude. You should only attempt a source install if binary packages are not available for some reason, or if you have unusual needs that are not met by binary packages.
If you are using a Debian system, execute the following
aptitude. If you are not using a Debian system,
your system provider might have created a pre-built package
of aptitude; if you are not sure, you can contact them for