title: How do I use a regular expression to match a fixed-length number with a hyphen in the middle?
body: <p>I am new to regular expressions and wanted to know how to write a regular expression that does the following:</p>
  
  <p>Validates a string like 123-0123456789.  Only numeric values and a hyphen should be allowed.  Also, verify that there are 3 numeric chars before the hyphen and 10 chars after the hyphen.</p>