What is the purpose of -oG and how can you parse its output to extract open ports?

• A. -oG provides grepable output; you can filter lines with '/open/' to list open ports programmatically
• B. -oG outputs JSON; you can parse the 'open' fields
• C. -oG writes to a single log file; search for 'OPEN' everywhere
• D. -oG outputs XML; extract port numbers with XPath

Answer: (A)

Greppable output designed for text processing is what -oG provides. Because the format is tailored for tools like grep, awk, and sed, you can pull out open ports by filtering for the marker that appears in the Ports section when a port is open. For example, running a scan with grepable output and filtering with grep '/open/' yields lines such as: Host: 192.168.0.5 () Ports: 22/open/tcp//ssh///, 80/open/tcp//http///. From there, extracting just the port numbers is straightforward with standard text tools, e.g. pipe to cut -d'/' -f1 to grab the number before the first slash. This makes open-port data easy to access programmatically.