Is there a linux command to determine the window IDs associated with a given process ID?

Question

Given a process iD of XX, I\'d like to have a list of any window id\'s where _NET_WM_PID = XX. Even better would be the oldest still active window id if possible.

I

Answer 1

xterm $WINDOWID feature

Under xterm environment as some other implementation, you could find this variable:

echo $WINDOWID
58720292

So for any other pid:

Shortly by using sed:

targetpid=12345
sed -zne 's/WINDOWID=//p' /proc/$targetpid/environ

...

xdotool windowactivate $(sed -zne 's/WINDOWID=//p' /proc/$targetpid/environ)

Or in a pure bash function:

getWinFromPid () { 
    local pid=$1 array line
    [ -z "$pid" ] || [ ! -d /proc/$pid ] && return -1
    local -n result=${2:-winIDfromPid[$pid]}
    mapfile -d $'\0' -t array 

Then

getWinFromPid 123456 myWinId
xdotool windowactivate $myWinId

For other term, like gnome-terminal:

This is strong because we don't want pid of terminal process, but pid of shell using terminal. For sample:

wmctrl -lp

don't show wanted pids!

So we have to navigate in hierarchy of process

1. Get Window ID from process ID

1a. Current active terminal window

From active session himself:

SHWINID=$(xprop  -root | sed -ne 's/^_NET_ACTIVE_WINDOW.*[)].*window id # //p')

This work as you type this in any active terminal console.

Then now, with xdotool:

sleep 12; xdotool windowactivate $SHWINID

You can now switch to another window, will be back in 12 seconds.

1b. Window ID from any shell or subprocess ID

I wrote this little function:

getWinFromPid () { 
    local pid=$1 ttypid crtpid wid xprop ttycheck
    [ -z "$pid" ] || [ ! -d /proc/$pid ] && return -1
    local -n result=${2:-winIDfromPid[$pid]}
    read ttycheck < <(ps ho tty $pid)
    ttypid=$ttycheck
    while [ "$ttypid" = "$ttycheck" ]; do
        crtpid=$pid
        read pid ttypid < <(ps ho ppid,tty $pid)
    done
    result=
    while [ -z "$result" ] && read wid; do
        xprop=$(xprop -id $wid)
        [ "$xprop" ] && [ -z "${xprop//*_NET_WM_DESKTOP*}" ] &&
            [ -z "${xprop//*_NET_WM_PID(CARDINAL) = $crtpid*}" ] && result=$wid
    done < <(xwininfo -root -children -all |
       sed -e '1,/children:$/d;s/^ *\(0x[0-9a-fA-F]\+\) .*/\1/p;d')
}

Then

getWinFromPid  []

If no variable name submited, this will populate global array $winIDfromPid with pid id as index number:

getWinFromPid 1234 winId
echo $winId
0x0100012345

getWinFromPid 1234
echo ${winIDfromPid[1234]}
0x0100012345

declare -p winIDfromPid 
declare -a winIDfromPid=([1234]="0x0100012345")

Nota: this was tested with xterm, mate-terminal, konsole and gnome-terminal.

Nota2: If you already have wmctrl installed, you could replace two last lines of function:

    done < <(xwininfo -root -children -all |
       sed -e '1,/children:$/d;s/^ *\(0x[0-9a-fA-F]\+\) .*/\1/p;d')

by:

    done < <(wmctrl -l|sed -ne 's/^ *\(0x[0-9a-fA-F]\+\) .*/\1/p');}

function will become approx 2time faster.

2. Get process running PID from a window ID

winID=0x123456
ps --ppid $(xprop -id $winID _NET_WM_PID|sed s/.*=//) ho sid |
    xargs -I{} -n1 ps --sid {} fw

or without ID, you will have to click with mouse:

ps --ppid $(xprop _NET_WM_PID|sed s/.*=//) ho sid|xargs -I{} -n1 ps --sid {} fw

Into a function

psWin() {
    ps --ppid $(xprop ${1+-id} $1 _NET_WM_PID|sed s/.*=//) ho sid |
        xargs -I{} -n1 ps --sid {} fw
}

Then:

psWin $SHWINID
  PID TTY      STAT   TIME COMMAND
30529 pts/2   Ss     0:00 bash
19979 pts/2   S+     0:00  \_ bash
19982 pts/2   S+     0:00      \_ xargs -I{} -n1 ps --sid {} fw
19986 pts/2   R+     0:00          \_ ps --sid 30529 fw

3. List of shell windows, with process

Finally, there is a little function for showing a list of window with process.

shWinList () {
    local pids=() wids=() wtitl=() ttys=() pid ttypid wpid crtpid line title desk ttycheck
    for pid in $(ps axho pid,tty| sed -ne 's/ pts.*//p') ;do     # list pid / tty
        wpid=$pid ttypid=
        read ttycheck < <(ps ho tty $pid)
        ttypid=$ttycheck
        while [ "$ttypid" = "$ttycheck" ]; do
            crtpid=$wpid
            read wpid ttypid < <(ps ho ppid,tty $wpid)
        done
        [ -e /proc/$pid ] && pids[crtpid]+=$pid\  ttys[crtpid]=$ttycheck
    done
    while read wid; do   title= pid= desk=                       # list wid / tty
        while read line; do
            [ "$line" ] && { 
                [ -z "${line%%_NET_WM_PID*}" ] && pid=${line##*= }
                [ -z "${line%%WM_NAME*}" ] &&
                    title=${line#*\"} title=${title%\"*}
                [ -z "${line%%_NET_WM_DESKTOP(*}" ] && desk=${line##*= } ;}
        done < <(xprop -id $wid)
        [ "${pids[pid]}" ] && [ "$title" ] && [ "$desk" ] &&
            wtitl[16#${wid#0x}]=${title} wids[16#${wid#0x}]=${pids[pid]} \
                 ttys[16#${wid#0x}]=${ttys[pid]}
    done < <(xwininfo -root -children -all |
                 sed -ne 's/^ *\(0x[0-9a-fA-F]\+\) .*/\1/p')
    for xwin in ${!wids[@]} ;do  out=                            # merge & print
        printf "  0x%x %-9s %-40s " $xwin "${ttys[$xwin]}" "${wtitl[$xwin]}"
        for pid in ${wids[$xwin]} ;do
            mapfile -d '' cmdl < /proc/$pid/cmdline
            echo -n " $pid[${cmdl[*]}]"
        done ; echo
    done
}

Then

shWinList
  0xa600024 pts/42    user@hostloc: /tmp            14817[bash]
  0x1c00024 pts/3     user@hostloc: ~               29349[watch ps --tty pts/3 fw] 31989[bash]
  0x4600024 pts/16    user@remote: ~                14441[ssh user@remote]
  0x6000024 pts/43    user@hostloc: ~               5728[bash]