With the new release of GRASS, this command can be ran (like d.zoom) from the graphical interface by pressing this button on the Display Manager, like in many other GIS.
If a database table has been connected with the vector map, clicking on an object makes a popup window appear, displaying the related record of the database. Data can be updated directly from the form and it will be automatically saved in the database table.

Synopsis: (example)

> d.what.vect map=strade

On the right form are displayed all the information related to the selected (in violet) object (in this case the object is a street and information are about street's name and lenght, date and CO hourly emissions for that day).

For further informations