When you request that a package is installed, and as a result
other packages are installed to satisfy its dependencies, the
dependencies are marked as being automatically installed, while
- package you installed explicitely is marked as manually installed.
+ package you installed explicitly is marked as manually installed.
Once a automatically installed package is no longer depended on
by any manually installed package it is considered no longer needed
and e.g. <command>apt-get</command> or <command>aptitude</command>