Best guess - the code got corrupted while being copied.

Or maybe while being "simplified".

Since you didn't post the actual code you are running, it's hard to tell :(

The code which I tried to run:


local $_ = join '', sort map "$_\n", map {
    join ',', reverse split /,/
    }
  map s/\.\/|\n//gr, <DATA>;

sub transpose
  {
  my $tmp = '';
  $tmp .= "\n" while s/^./ $tmp .= $&; '' /gem;
  $_ = $tmp;
  }

my @p = map quotemeta, /[^,\s]+/g;
my $lead = do { local $" = '|'; qr/(@p)/ };
1 while s/^[-| ]*\K$lead,/|-- /m;
my $line = '';
$line |= $_ for /.+/g;
my $length = length $line;
s/.+/ sprintf "%-${length}s", $& /ge;
transpose;
s/\|*\K\|/`/g;
transpose;
s/ +$//gm;
s/--(?= [|`])/  /g;
s/^/    /gm;
s/    /`-- /;
print;

__DATA__
./strict.pm,./hello_world.pl
./strict.pm,./bye.pl,./hello_world.pl
./hello_world.pl
./bye.pl,./hello_world.pl
./bin-perl,./hello_world.pl
./bin-perl,./bye.pl,./hello_world.pl
[download]

It's before I tried to simplified. Speaking about simplifying. I really have no I idea what those operators do. Do you have a link where I can view them?

The code you just posted runs fine on my linux machine.

Are you running it in a standard terminal?
Are you trying to run it in a browser?

You don't need a link, just use perldoc. Start with "perldoc perl" on your command line.