I've written two recursive functions that trace parents of a process

get_parent()

{

 ps --no-headers -p $1 -o ppid,cmd 

}



process_list()

{

  if [ "$1" -ne "1"  ]; then

   PARENT="$(get_parent $1 )"

   printf "%s

" "$PARENT"

   process_list $( printf "%s" "$PARENT" | awk '{print $1}'  )

  fi 

}



print_header()

{

  printf "PPID	PROCESS

"

  for i in $(seq 1 20 ) 

  do

     printf "-"

  done

  printf "

"

}

print_header

process_list $$

What I've found in the process is this:

$ bash get_process_list                                                        

PPID    PROCESS

--------------------

31264 bash get_process_list

31251 mksh

16696 gnome-terminal

15565 /bin/mksh

 2164 x-terminal-emulator

 1677 init --user

 1342 lightdm --session-child 12 19

    1 lightdm

So we could use the two functions and grep the gnome-terminal, assuming that's what the user wants. If the user wants any terminal emulator, that may be problematic because aside from checking lsof for a pts device open, there's no way to tell whether or not the process is a terminal emulator.

Aside from that , there is something very interesting as well:

$ bash get_process_list                                                                    

PPID    PROCESS

--------------------

32360 bash get_process_list

23728 -mksh

 2164 tmux

 1677 init --user

 1342 lightdm --session-child 12 19

    1 lightdm

tmux apparently forks itself and the process gets picked up by init , so again there's the obstacle.

Using Unity's Ayatana

The code bellow uses qdbus and Ayatana's dbus interface to list all gnome-terminal windows and whether they are focused at the moment or not. This can be later parsed or edited to output only active/focused window PID

Sample run:

$ bash get_gt_pd.sh                                                                    

XID:33554486    PID:20163   ACTIVE:true

XID:33554444    PID:20163   ACTIVE:false

And the code itself

get_gt_xid()

{ # Prints XID of each gnome-terminal window

 qdbus --literal org.ayatana.bamf 

      /org/ayatana/bamf/matcher 

     org.ayatana.bamf.matcher.XidsForApplication 

    /usr/share/applications/gnome-terminal.desktop

}



for window in  $(get_gt_xid | awk -F'{' '{ gsub(/,|}|]/," ");print $2  }' )

do

  PID=$(qdbus org.ayatana.bamf /org/ayatana/bamf/window/"$window"

        org.ayatana.bamf.window.GetPid)

  ACTIVE=$( qdbus org.ayatana.bamf /org/ayatana/bamf/window/"$window"

            org.ayatana.bamf.view.IsActive  )

  printf "XID:%s	PID:%s	ACTIVE:%s

" "$window" "$PID" "$ACTIVE"

done