Formation of sample according to the reference

The command vsn offers two possibilities to make selection according to the references. Either one looks for the stars in a given reference, which is done with option -eq, or one wishes the data from the references which are different from the given reference, which is accomplished with the option -ne.

Extraction of the data for a given reference:
vsn ref -eq source
Extraction of the data from all references, except the given one:
vsn ref -ne source

Examples:

vsn ref -e 10 lists the data from reference 10
vsn ref -n 10 lists all the data that do not belong to reference 10