title: How to mentally rationalize apt-get install "unable to find package error" and outline a troubleshoot approach
body: <p>I've been programming for about 6 months but have just started moving into Operating Systems and the internals of Linux/Ubuntu and how OS's work in general. For my job, I'm tasked to do a lot of configuration setups with packages Linux, nginx,rails, etc and every once in a while I run into an error like the one I am currently experiencing.</p>
  
  <pre><code>sudo apt-get install cvsnt
  
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  E: Unable to locate package cvsnt
  </code></pre>
  
  <p>These errors frustrate me because I don't have a formulated attack plan to troubleshoot it. I'm taking EdX's introduction to Linux and that has been helpful, but the internals of Linux is still a mystery me and when something like this pops up its very difficult for me to figure out what to do. Most of the time I hope that stackoverflow has an answer for the specific problem I'm having.</p>
  
  <p>So how would I attack this problem? There is no error that is helpful other than that the package has not been found. Do I check the CVSNT docs first? Is there something wrong with Ubuntu Linux? Is there something wrong with dpkg? Is there a file to check for stuff? Is it a path problem? Where do you start. I'd like to be able to navigate through these problems effectively because they won't be going away anytime soon as long as I'm assigned to configure things. Thanks.</p>