title: Cygwin commands don't work
body: <p>I'm sorry that my question seems rather vague but this is the entire problem i'm facing. I tried installing an rpm package on cygwin after downloading it from the website but i always get the same error</p>
  
  <pre><code>-bash: rpm: command not found
  </code></pre>
  
  <p>and I have reinstalled it twice, but i always get the same problem, and it's not just that, i can't even use simple commands like ls. Even if i write ls I get no output. This is what my screen looks like.</p>
  
  <pre><code>User@User-PC ~
  $ rpm -ivh avr-binutils-2.17tinyos-3.cygwin.i386.rpm
  -bash: rpm: command not found
  
  User@User-PC ~
  $ locate rpm | grep bin
  
  User@User-PC ~
  $ 
  
  User@User-PC ~
  $ ls
  
  User@User-PC ~
  $
  </code></pre>
  
  <p>what do I do to fix this?</p>