/property: = Set or override these project-level properties. is the property name, and is the property value. Use a semicolon ...

/property:=  Set or override these project-level properties.  is
                     the property name, and  is the property value. Use a
                     semicolon or a comma to separate multiple properties, or
                     specify each property separately. (Short form: /p)
                     Example:
                       /property:WarningLevel=2;OutDir=bin\Debug\