Successful brew install iftop still shows "sudo iftop: command not found"
I had to add /usr/local/sbin to /etc/paths. But that add does nothing if you do not close and reopen terminal. Terminal apparently loads paths when it opens, but does not see new changes while open.


sudo nano /etc/paths
Then add the path /usr/local/sbin, Ctrl-O to save, Ctrl-X to close
Restart Terminal (or just open a new tab), then run sudo iftop