How can I display contents of trash using terminal?
You can run
ls -al ~/.Trash
to show the content of the Trash of the current user.
To see the content of all Trashes, use
sudo ls -al /Users/*/.Trash
from an admin account.
And if you also want to include the content of the Trash on external volumes, use
sudo sh -c 'ls -al /Volumes/*/.Trashes/*/'