This is a Heroku buildpack for adding rar and unrar to your application.
More likely, you'll want to use it as part of a larger project, which needs to use rar and unrar. The easiest way to do this is with a multipack, where this is just one of the buildpacks you'll be working with.
$ cat .buildpacks git://github.com/heroku/heroku-buildpack-ruby.git git://github.com/hasibulkabir/heroku-buildpack-rarlab.git $ heroku config:add BUILDPACK_URL=git://github.com/ddollar/heroku-buildpack-multi.git
By this you can use rar and unrar command.
heroku config:add BUILDPACK_URL=git://github.com/HasibulKabir/heroku-buildpack-rarlab.git"
Copy the snippet above into CLI.