$mac = join( ':' => ($mac =~ /(..)/g) );

##</code><code>##

$mac = join( ':' => ($mac =~ /../g) );

##</code><code>##

join("", my_slurp_file_function($fname) =~
   /^=begin[ \t]+$sname[ \t]*\n(.*?)^=end[ \t]+$sname[ \t]*$/msg);