Fix the constructor message in complex queries

Signed-off-by: zhuzeyu <zhuzeyu0409@gmail.com>

docs/source/couchdb_tutorial.rst

@@ -641,6 +641,7 @@ the marbles chaincode:
 .. code:: bash
 
   // Example one: query fully supported by the index
+  export CHANNEL_NAME=mychannel
   peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["queryMarbles", "{\"selector\":{\"docType\":\"marble\",\"owner\":\"tom\"}, \"use_index\":[\"indexOwnerDoc\", \"indexOwner\"]}"]}'
 
 The marbles chaincode was installed with the ``indexOwnerDoc`` index:
@@ -688,7 +689,7 @@ marble and every item owned by tom.
 .. code:: bash
 
   // Example four: query with $or supported by the index
-  peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["queryMarbles", "{\"selector\":{"\$or\":[{\"docType\:\"marble\"},{\"owner\":\"tom\"}]}, \"use_index\":[\"indexOwnerDoc\", \"indexOwner\"]}"]}'
+  peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["queryMarbles", "{\"selector\":{\"$or\":[{\"docType\":\"marble\"},{\"owner\":\"tom\"}]}, \"use_index\":[\"indexOwnerDoc\", \"indexOwner\"]}"]}'
 
 This query will still use the index because it searches for fields that are
 included in ``indexOwnerDoc``. However, the ``$or`` condition in the query
@@ -700,7 +701,7 @@ Below is an example of a complex query that is not supported by the index.
 .. code:: bash
 
   // Example five: Query with $or not supported by the index
-  peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["queryMarbles", "{\"selector\":{"\$or\":[{\"docType\":\"marble\",\"owner\":\"tom\"},{"\color\":"\yellow\"}]}, \"use_index\":[\"indexOwnerDoc\", \"indexOwner\"]}"]}'
+  peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["queryMarbles", "{\"selector\":{\"$or\":[{\"docType\":\"marble\",\"owner\":\"tom\"},{\"color\":\"yellow\"}]}, \"use_index\":[\"indexOwnerDoc\", \"indexOwner\"]}"]}'
 
 The query searches for all marbles owned by tom or any other items that are
 yellow. This query will not use the index because it will need to search the