my $filename = '/tmp/somefile.html';
my $find = "<option SELECTED>[ Current time range ]";

my $replace = '<option SELECTED> Current time';
{
   local @ARGV = ($filename);
   local $^I = '.bac';
   while( <> ){
      if( s/$find/$replace/ig ) {
         print;
      }
      else {
         print;
      }
   }
}