That's 1. a security risk, and 2. probably not portable.

You should at least tell us which OS you're running this on.

That is pretty much what I want to do. I have emulated a similar application that runs on windows and does exactly what I am trying to do. I am running this on Linux (Puppy 3.01 if it matters). I simply want to hijack the arrow keys while my application is minimized.

Try this(Escape key is the only way to close):

#!/usr/bin/perl
use Tk;
$mw = MainWindow->new;

# the window must be mapped for a global grab
# so make a 1 pixel window in lower right corner
$mw->geometry('1x1-1-1');

$mw->bind("<Key>", [  \&process_key_press , Ev('K')  ] );
$mw->bind("<KeyRelease>", [ \&process_key_release , Ev('K')  ] );

$mw->after(100,sub{$mw->grabGlobal;});
$mw->focusForce;

MainLoop;

sub process_key_press{
  my ($caller, $key) = @_;
   print "Press $key\n"; 
   if ($key eq 'Escape'){exit}
}

sub process_key_release{
  my ($caller, $key) = @_;
   print "Release $key\n"; 
}
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Zentara, I think he was after a global hotkey, which works regardless of which app has focus. AFAIK there is no uniform way of doing this on linux, it depends on the window manager in use.

Zentara, Thank you for the example. It doesn't quite do the trick though. I need something that allows me to open another application even when this is running and your example does not seem to allow this. Let me explain exactly what I'm trying to do: I have a Pan/Tilt/Zoom camera control application built with Perl/Tk. I need to use it with a web browser opened to a webcam site. Everything works very well except that when the control application looses focus, the bindings to the keys (up, down, left, right arrows) stop working until the application gets focus again. A hotkey won't work either unless I change my application to run as a daemon so it can listen to external commands as far as I can tell. I don't want more that one application to run as I'd like to keep it simple and easily portable to other machines.