title: What are valid characters for Windows environment variable names and values?
body: <p>After some reseach, I found out that <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/ms682653%28v=vs.85%29.aspx">length limits</a> for names are 255 and for values 32767 characters.</p>
  
  <p>But which characters are allowed for <em>names</em>?<br>
  And which characters are allowed for <em>values</em>?</p>