AppleScript to check if application is open on host and networked Mac

Question

Hello
Hoping someone can help me with an AppleScript.
Background: I'm running ChronoSync to bi-directionally sync iTunes and one-way mirror my Aperture libraries between a MacPro and an external drive attached to a MacBook Pro. ChronoSync has told me that it's recommended to have the applications closed on both machines and that a script to check this and error if not would be a good way to be sure (the error would be picked up my ChronoSync and abort the sync process).
So, I need a script that sits on the Mac Pro and can check whether Aperture or iTunes is open on that machine or, if it's available on the network, the MBP. If either are open, the script should error invisibly and that will abort the sync. I want to avoid any dialogues or other notifications of the error, and let syncing take place invisibly only when the applications are shut down.
Any help much appreciated.
Thanks
Ben

Answer 1

There are various ways of doing this. One is to ask System Events for a list of all running processes and just check for the one in question:
tell application "System Events"
  if (get name of every application process) contains "Shades" then
  -- your code here
  end if
end tell
You may need to check how the app presents itself to System Events. Some use the short application name (e.g. 'Shades') while others, especially backgound apps, may use application IDs such as 'com.apple.WebKit.WebDeveloper', but a quick check of the output of 'every application process' should be easy enough.