You can specify individual properties on the command line, using the syntax
/property:<name>=<value>
or
/p:<name>=<value>
Only property types which support conversion to and from string can be assigned in this way.
You can include multiple instances of the /property switch on the command line to define multiple properties in this way.
If you specify both a property set XML file and a property value on the command line, the property value will override any setting in the property set XML file.