James-MacBook-Pro:blog user$ sudo brew install iftop
Password:
==> Downloading http://www.ex-parrot.com/pdw/iftop/download/iftop-1.0pre4.tar.gz
######################################################################## 100.0%
==> ./configure --prefix=/usr/local/Cellar/iftop/1.0pre4 --mandir=/usr/local/Cellar/iftop/1.0pre4/share/man
==> make install
==> Caveats
iftop requires root privileges so you will need to run `sudo iftop`.
You should be certain that you trust any software you grant root privileges.
==> Summary
🍺 /usr/local/Cellar/iftop/1.0pre4: 9 files, 102.2K, built in 9 seconds
James-MacBook-Pro:blog user$ sudo iftop
sudo: iftop: command not found
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