というツールを作りました lswin
$ python lswin.py
    PID WinID  x,y,w,h                  [Title] SubTitle
------- -----  ---------------------    -------------------------------------------
    169  1956 {0,-38,1280,25        }   [Window Server] Backstop Menubar
    169  1955 {0,-60,1280,22        }   [Window Server] Menubar
    169   396 {0,-38,1280,25        }   [Window Server] Backstop Menubar
    169   395 {0,-60,1280,22        }   [Window Server] Menubar
    169     6 {0,0,0,0              }   [Window Server] Cursor
    169     4 {0,22,1280,25         }   [Window Server] Backstop Menubar
    169     3 {0,0,1280,22          }   [Window Server] Menubar
    169     2 {0,0,1280,800         }   [Window Server] Desktop
    262   404 {0,-38,1280,38        }   [Google Chrome] 
    262   393 {0,0,1280,800         }   [Google Chrome] 
    262   380 {100,100,1,1          }   [Google Chrome] Focus Proxy
    ... ...
次に、grepを使用して、ウィンドウのpidを見つけることができます。
スクリプトのソースコードは次のとおりです。
#!/usr/bin/env python
import Quartz
#wl = Quartz.CGWindowListCopyWindowInfo( Quartz.kCGWindowListOptionOnScreenOnly | Quartz.kCGWindowListExcludeDesktopElements, Quartz.kCGNullWindowID)
wl = Quartz.CGWindowListCopyWindowInfo( Quartz.kCGWindowListOptionAll, Quartz.kCGNullWindowID)
wl = sorted(wl, key=lambda k: k.valueForKey_('kCGWindowOwnerPID'))
#print wl
print 'PID'.rjust(7) + ' ' + 'WinID'.rjust(5) + '  ' + 'x,y,w,h'.ljust(21) + ' ' + '\t[Title] SubTitle'
print '-'.rjust(7,'-') + ' ' + '-'.rjust(5,'-') + '  ' + '-'.ljust(21,'-') + ' ' + '\t-------------------------------------------'
for v in wl:
    print ( \
        str(v.valueForKey_('kCGWindowOwnerPID') or '?').rjust(7) + \
        ' ' + str(v.valueForKey_('kCGWindowNumber') or '?').rjust(5) + \
        ' {' + ('' if v.valueForKey_('kCGWindowBounds') is None else \
            ( \
                str(int(v.valueForKey_('kCGWindowBounds').valueForKey_('X')))     + ',' + \
                str(int(v.valueForKey_('kCGWindowBounds').valueForKey_('Y')))     + ',' + \
                str(int(v.valueForKey_('kCGWindowBounds').valueForKey_('Width'))) + ',' + \
                str(int(v.valueForKey_('kCGWindowBounds').valueForKey_('Height'))) \
            ) \
            ).ljust(21) + \
        '}' + \
        '\t[' + ((v.valueForKey_('kCGWindowOwnerName') or '') + ']') + \
        ('' if v.valueForKey_('kCGWindowName') is None else (' ' + v.valueForKey_('kCGWindowName') or '')) \
    ).encode('utf8')