title: Source RVM script - "grep: invalid option -- 'p'"
body: <p>Whenever I try to use RVM on Ubuntu or one of it's derivatives, I get the following error:</p>
  
  <p><code>grep: invalid option -- 'p'
  Usage: grep [OPTION]... PATTERN [FILE]...
  Try 'grep --help' for more information.</code></p>
  
  <p>I checked <code>type grep</code>, and got 
  <code>grep is /bin/grep</code>.
  So grep is not aliased.</p>
  
  <p>Is this a known bug in RVM? If not, what else could be causing this behavior?</p>
  
  <p>EDIT: This occurs when I <code>source ~/.bash_profile</code>. I've gone and reproduced the behavior when I run just the RVM related part.</p>