Final answer:
In SQL, the command to change the name to "Greg" for all cats that are 11 years old in the 'cats' table is: UPDATE cats SET name = 'Greg' WHERE age = 11.
Step-by-step explanation:
You've asked how to write a command for the table cats that changes the name to "Greg" for all cats who are 11 years old. Assuming you are using SQL (Structured Query Language), the command would look like this:
UPDATE cats SET name = 'Greg' WHERE age = 11;
This SQL statement updates the name field to "Greg" for all records in the cats table where the age is equal to 11.