title: Perl: identification of unknown code
body: <p>I have to include a perl script into a web system for my work, however the original author is no longer here and no one else in the office knows perl.<br>
  I've only first dealt with perl this morning and i'm stuck trying to figure out a couple lines that maybe someone might be able to help with</p>
  
  <pre><code>1] $customer = $q-&gt;param('account') || '';
  2] $customer =~ s/[^\d]//g; 
  3] $customer ||= ''; 
  4] if( $customer and ( $customer =~ /^10\d{5}$/ or $customer eq '1' ) ) {
  5]    $no_error = 1;
  6] }
  </code></pre>
  
  <p>I found out that line 2 removes all non-numeric values, but I am not so sure how that statement actually functions..?<br>
  Again, i'm unsure to what <code>=~ /^10\d{5}$/</code> means.<br>
  Line 3 is the main one i cannot figure out, i'm used to <code>||</code> meaning logical <code>OR</code>.</p>