<listitem><para><option>upgrade</option> is used to install available
upgrades of all packages currently installed on the system from the
sources configured via &sources-list;. New packages will be
- installed if required to statisfy dependencies, but existing
+ installed if required to satisfy dependencies, but existing
packages will never be removed. If an upgrade for a package requires
the remove of an installed package the upgrade for this package
isn't performed.