How can I tell state of program seemingly running

Question

I had Firefox running, then (possibly) as a result of a key combination I don't recall, it quickly vanished from screen and Task Bar/Window List.

ps ax | grep firefox returns the below+the unneeded grep firefox line (Both ps and the GUI Task Manager, show firefox with seemingly unchanging RSS, VM-SIZE and 0% CPU usage):

johndoe      1916 36.6 14.0 923772 504372 tty1    Sl   13:30  12:15 firefox

*CORRECTED*
pstree | grep firefox returns:

init─┬─2*[ROX-Filer───firefox───25*[{firefox}]]

How can I tell what state the program is in?

Answer 1

It's probably a zombie process.

Z defunct ("zombie") process, terminated but not reaped by its parent.

If you run ps ax | grep firefox it will show you the status of the process, you can check against this list of status of the process (you must read the STAT column). Sadly, is unlikely that without fiddling with debuggers you can recover your data.

tree probably doesn't show you the process for the same reason.

Answer 2

Personally, I like top run from the command line. Works to find that one app that is slowing everything down.