$ wget -qO- https://cli-assets.heroku.com/install-ubuntu.sh | sh
$ wget https://cli-assets.heroku.com/heroku-cli/channels /stable/heroku-cli-REPLACEME_OS-REPLACE_ME_ARCH.tar.gz -O heroku.tar.gz
--2017-08-24 02:13:33-- https://cli-assets.heroku.com/heroku-cli/channels /stable/heroku-cli-REPLACEME_OS-REPLACE_ME_ARCH.tar.gz
Resolving cli-assets.heroku.com (cli-assets.heroku.com)... 54.192.209.81,54.192.209.52, 54.192.209.134, ...
Connecting to cli-assets.heroku.com (cli-assets.heroku.com)|54.192.209.81|:443... connected.
HTTP request sent, awaiting response... 404 Not Found
2017-08-24 02:13:38 ERROR 404: Not Found.
How about this?
$ mv heroku-cli-v6.x.x-darwin-64 /usr/local/lib/heroku
mv: cannot stat ‘heroku-cli-v6.x.x-darwin-64’: No such file or directory