$directory =~ s<^/*></>
               .   </*$></>;

##</code><code>##

    $directory =~ 
        s< ^  /?            # match leading '/' if present
              (             # capture what is between ends
                [^/]*       # match anything not a '/'
                (?:         # might be a '/', 
                  (?! /$ )  # but don't allow a '/' at EOL
                  .         # okay, eat the '/'
                ) *
              )
              /? $          # match trailing '/'
         >
         </$1/>x;    # now surround the middle with '/'