Ruby 备份gem与openafs客户端混淆

我下面是一篇关于Ruby备份gem的入门文章

我运行了

gem install backup

，效果很好，但当我尝试运行时：

backup generate:model --trigger my_backup \
--archives --storages='local' --compressor='gzip' --notifiers='mail'

我得到了错误信息：

The program 'backup' is currently not installed. You can install it by typing:
sudo apt-get install openafs-client

我使用的是Ubuntu 14.04

知道我的问题是什么或如何解决吗

更新： -Ruby版本：

Ruby 2.1.6p336（2015-04-13修订版50298）[x86\u 64-linux]

-使用rbenv

echo $PATH
/usr/local/heroku/bin:/home/stoebelj/.rbenv/plugins/ruby-build/bin:/home/stoebelj/.rbenv/shims:/home/stoebelj/.rbenv/bin:/home/stoebelj/.rbenv/plugins/ruby-build/bin:/home/stoebelj/.rbenv/shims:/home/stoebelj/.rbenv/bin:/home/stoebelj/.rbenv/plugins/ruby-build/bin:/home/stoebelj/.rbenv/shims:/home/stoebelj/.rbenv/bin:/home/stoebelj/.rbenv/plugins/ruby-build/bin:/home/stoebelj/.rbenv/shims:/home/stoebelj/.rbenv/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin:/home/stoebelj/.rvm/bin:/home/stoebelj/.rvm/bin

---

你的ruby版本是什么？备份版本打印什么？ruby是如何安装的（rvm/rbenv/一些软件包/等等）？您的

echo$PATH

是什么？更新中给出了答案。