I'd try it out but I don't have l^Hbsd. One initial reaction, upon glancing at the code, however, was that the following code could and probably should be transformed into a hash dispatch:

  if    ($sel == 1) { show_installed() }
  elsif ($sel == 2) { show_available() }
  elsif ($sel == 3) { rgetpkglist()    }
  ...
[download]

Like so:

  my %dispatch = (
    1 => \&show_installed,
    2 => \&show_available,
    3 => \&rgetpkglist,
    ...
  }

  $dispatch{$sel}->();
[download]

   MeowChow                                   
               s aamecha.s a..a\u$&owag.print