link files were created as follows: (so we can type X rather than X.sh)
ln -s lstree.sh lstree
chmod +x lstree
This is precompiled and downloaded from github.
origin = https://github.com/antonmedv/countdown/releases
The current binary works ok on Ubuntu.
To install for Mac:
brew install go
go get github.com/antonmedv/countdown
chomd +x countdown