Final answer:
The command 'cat >> /cases/wisp-body' appends the contents of a file to another file, or creates a new file if it doesn't exist.
Step-by-step explanation:
The command cat >> /cases/wisp-body is used to append the contents of a file to another file, or create a new file if it doesn't exist. In this case, it is appending the contents of the file being read by the 'cat' command to the file '/cases/wisp-body'.