Just let less do its thing for you.

• Either pipe the output from your program to less:

  yourApp | less
  [download]

• Or do the same thing from within the program with a piped open:

  open LESS, '| less' or die $!;
  select LESS;
  
  ## print stuff as normal.
  
  ...
  
  select STDOUT;
  close LESS;
  [download]

According to an item in the less FAQ, it appears to use the termcap libraries for screen handling. There are at least one or two modules, including Term::Cap, that appear to interface that library.

Alternately, you might also be able to use another screen-handling module (such as the Curses module) to manipulate the output as you desire.

HTH.

I haven't messed with any of this stuff in about 8 years but suspect you'll find what you need in things like Term::Screen and Term::Cap. Search for "term" at search.cpan.org for more possibilities.

Tk, although that may be a little fraught using a terminal session under *nix (would work fine with Windows though).

What you are describing is the "alternate screen" feature that some terminal emulators have. The linux virtual console, for instance, doesn't have this feature.

not leaving a trace in your terminal.

Actually this is not 100% true. In xterm you can find "Show alternate screen" in the menu that opens when you hold down Ctrl-MiddleButton. Even after less has been quit, xterm still shows its display (of your secret files) in the alternate screen.

Update: Regarding your question how you can do this: I think that ncurses (which "less" uses) does this by default when you initiate the screen, so you should be able to do this with the Curses module (as atcroft suggests).