use strict;
use warnings;

local $/ = "Window ";

while (<DATA>) {
    chomp;
    next if ! length;
    my $paragraph = $/ . $_;
    
    print "$paragraph\n";
}

__DATA__
Window 0x800022:
  Machine:  genus
  Name:  xterm
  Icon Name:  xterm
  Command:  xterm -u8 -geometry 156x62+190+-2
  Instance/Class:  xterm/XTerm
Window 0xc00022:
  Machine:  genus
  Name:  ~
  Icon Name:  psh
  Command:  xterm -e /usr/bin/psh
  Instance/Class:  xterm/XTerm
Window 0xe00001:
  Machine:  genus
  Name:  Gecko
  Icon Name:  mozilla-bin
  Command:  mozilla-bin
  Instance/Class:  mozilla-bin/Mozilla-bin