To see the contents of a .deb package file on a Debian or Ubuntu system, you can use the dpkg command with the --contents option. This will list the files contained within the package, along with their installation paths.
For example, to see the contents of the package file package.deb, you can use the following command:
dpkg --contents package.deb
Alternatively, you can use the dpkg-deb command with the --contents option to achieve the same result.
For example:
dpkg-deb --contents package.deb
You can also use the ar command to extract the contents of the package file to a directory. For example:
ar p package.deb data.tar.gz | tar zxf -
This will extract the data.tar.gz file contained within the package.deb file, which contains the files that will be installed by the package.