The tcpdump command is a network packet analyzer tool that can capture and display network traffic. The -w option specifies a file name to write the captured packets to, in a binary format that can be read by tcpdump or other tools later. This option is useful for capturing large amounts of network data that will be analyzed at a later time, as the question requires. The packet capture does not need to be in a format that is readable by humans, since it will be put into a binary file called "packetCapture". The capture must be as efficient as possible, and the -w option minimizes the processing and output overhead of tcpdump, reducing the likelihood that packets will be missed.