The "*" quantifier is used to know the number of times a character or a sequence preceding "*" may occur at least zero or more times.It just matches any number of occurence or even if does'nt occur.

For example if we have a pattern "lt*" it matches the string that has the letter "l" followed by zero or more number of "t" as it is the preceding character to the quantifier "*". So the string matched would be "l","ltt","later" etc.

    <?php
    $name = "bcd";
    if (preg_match("/a(bcd)*/", $name))
     {echo "Pattern matches!";} 
    else 
     {echo "Pattern not matched!";}
    ?>

    Pattern not matched!

In the above example the possible matches are "a", "abcd", "abcdbcd" etc. Here "bcd" is grouped using a "()" to match zero or more times.

    #! C:\programfiles\perl\bin\perl
    print "content-type: text/html\n\n";
    if ("laaer" =~ m/lt*/) 
      {
       print "The pattern matched.!\n";
      } 
    else 
      {
       print "The pattern not found!\n";
      }

     The pattern matched.! 

In the above example's the pattern "lt*" means the string should start with "l" with a following "t" or even can be without a "t" ie., so the string "laaer" is matched.