The ij.protocol.protocolName property is similar to the ij.protocol property. The only difference is that it associates a name with the value, thus allowing you to define and use more than one protocol.
ij.protocol.protocolName=protocolForEnvironment
java -Dij.protocol.derby=jdbc:derby: \
-Dij.protocol.emp=jdbc:derby: org.apache.derby.tools.ij
ij version 10.13
ij> Connect 'newDB' protocol derby as new;
ij>