I’d heard about nmap before I knew about most of life at the console. Not that I understood it — or even do now — but I knew about it.
And I wouldn’t pretend to know or understand everything nmap can do. Like the other two, it’s exceedingly flexible and very powerful.
It’s worth learning if you have the time and the necessity. For my part, I can honestly say in the past six or seven years of Linux-only living, I have probably used it in earnest (meaning, not for the screenshot above 😉 ) about five times.
And each of those times, It was mostly a copy-and-paste network test. I can’t claim I know what I was really doing.
That’s my attempt to rationalize my ignorance by saying I (almost) never needed it. 🙄
But that’s all I’ll say, aside from
nmap -vv -A microsoft.com is a good place to start. Might as well harass Redmond while learning how to use these things. 😈
Oh! I almost forgot: Install nmap and you also get ndiff. Output your nmap scans to files, and you can use ndiff to show where they differ. You can thank me later. 😉