htop - an interactive process viewer for Unix
hisham.hm/htop
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Since version 2.0, htop is now cross-platform! Check out the video and slides of my presentation at FOSDEM 2016 about how this came to be. This release includes code supporting Linux, FreeBSD, OpenBSD and Mac OS X.