title: What character sequence should I not allow in a filename?
body: <p>I found out after testing that linux allows any character in a file name except for <code>/</code> and null (<code>\0</code>). So what sequence should I not allow in a filename? I heard a leading <code>-</code> may confuse some command line programs, which doesn't matter to me, however it may bother other people if they decide to collect a bunch of files and filter it with some GNU programs.</p>
  
  <p>It was suggested to me to remove leading and trailing spaces and I plan to only because typically the user doesn't mean to have leading/trailing space.</p>
  
  <p>What problematic sequence might there be and what sequence should I consider not allowing?
  I am also considering not allowing characters illegal in windows just for convenience. I think I may not allow dashes at the beginning (dash is a legal window character)</p>