to install upx, I was running this: ruby -e "$(curl -fsSL http s://raw.githubusercontent.com/Homebrew/install/master/install)" < /dev/null 2> /dev/null what was working, afterwards I was running this: brew install upx But then I am getting this answer: ==> Searching for similarly named formulae... Error: No similarly named formulae found. Error: No available formula or cask with the name "upx". ==> Searching for a previously deleted formula (in the last month)... Error: No previously deleted formula found. ==> Searching taps on GitHub... Error: No formulae found in taps. What have I done wrong?