You don't need the 'q{ }' in the line then. The join() command assembles a single string from the second and following parameters using the first parameter as a separator. So, if you said $str = join(q{asdf}, 1, ( 2, 4, 6 ));, then $str would contain '1asdf2asdf4asdf6', or if you said $str = join(q{|}, qw/a s d f z x c v/);, $str would contain 'a|s|d|f|z|x|c|v'. In the line you mention, there would be a space, followed by a tab character, then the value of $k, then a tab character, then the values in @data, separated by tab characters.

Hope that helps.