How to get a specific PID #

[Ralf Mardorf]

On Wed, 30 Dec 2015 19:06:58 -0800, rikona wrote:
>Wednesday, December 30, 2015, 1:14:53 PM, Ralf wrote:
>
>> On Wed, 30 Dec 2015 21:57:24 +0100, I wrote:  
>>>On Wed, 30 Dec 2015 22:20:28 +0200, Amichai Rotman wrote:   
>>>>Just use the 't' key to switch htop to 'tree mode'.    
>>>
>>>How does this show what xfw window belongs to what PID?
>>>
>>>  1  [||                                        2.8%]     Tasks: 59,
>>> 83 thr; 1 running 2  [|||
>>> 4.2%]     Load average: 0.03 0.04 0.05
>>> Mem[||||||||||||||||||||||||||||||||||||840/3704MB]     Uptime: 2
>>> days, 21:45:15 Swp[|                                    19/4706MB]
>>>
>>>  PID USER      PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+
>>> Command 7665 rocketmou  20   0  123M 14020 11652 S  0.0  0.4
>>> 0:00.19 ├─ xfw 7663 rocketmou  20   0  123M 13960 11592 S  0.0
>>> 0.4  0:00.14 ├─ xfw  
>
>> By the following example you can see, when using wmctrl I can see
>> what instance of pluma, IOW what window, belongs to what PID, but
>> for xfw the PIDs aren't displayed correctly. As shown by an earlier
>> reply, even if window title bars should share the same name, it's
>> possible to change the name with wmctrl, but this only makes sense,
>> if it also displays the PID.  
>
>> $ ps aux|grep -v grep|grep xfw
>> rocketm+ 28733  0.2  0.3 126964 13836 pts/4    S+   14:25   0:00 xfw
>> root     28734  0.0  0.1  72312  5216 pts/3    S+   14:26   0:00
>> sudo xfw root     28735  0.2  0.3 127744 14220 pts/3    S+   14:26
>> 0:00 xfw $ ps aux|grep -v grep|grep pluma
>> rocketm+ 28736  4.0  1.0 625936 40996 pts/2    Sl+  14:26   0:03
>> pluma root     28741  0.0  0.1  72312  5112 pts/1    S+   14:26
>> 0:00 sudo pluma root     28742  3.1  0.8 991168 32152 pts/1    Sl+
>> 14:26   0:01 pluma $ wmctrl -lp
>> 0x00a00003 -1 25836  archlinux panel
>> 0x00e0001d -1 25835  archlinux panel
>> 0x00800007  0 28670  archlinux rocketmouse at archlinux:~
>> 0x014004be  0 0            N/A .jackdrc - /home/rocketmouse
>> 0x018004bf  0 0            N/A .bashrc - /root
>> 0x01a00114  0 28736  archlinux .jackdrc (~) - Pluma
>> 0x01c00110  0 28742  archlinux .bashrc (~) - Pluma  
>
>
>wmctrl -lp does display the title bar BUT the PIDs in wmctrl are
>different from *most* of what is given by top, so it's a bit more
>difficult to get the correct PID to kill.
>
>Top lists many more PIDs than wmctrl - it seems that each tab in kate
>has a different PID - this seems to account for the difference in the
># of PIDs displayed. Other pgms display multiple tabs in a window that
>has only one PID, so different pgms work in different ways.

You seem not to understand what I explained, from all the things
explained by this thread wmctrl is the only way to get the PID that
belongs to a window.

wmctrl gives information about all windows, including the PID of the
program using this window, but it does not give information about all
the other programs that are running. 

top, htop, atop, ps aux gives information about all programs running,
but not about what program runs in what window.

>If I look in htop in tree mode it looks as though the extra tabs are
>listed as children to the main window PID. It looks like wmctrl
>displays only one PID for the kate 'window' which actually contains
>multiple PIDs. But, the # displayed IS the parent window PID, so this
>can give me the PID I need to kill the window.

You never mentioned that you want to exit a tab, you claimed you run
several windows of kate and want to close a window.

>If I do kill the 'parent' kate PID, would that also kill the children
>kate PIDs? If it would, is there a way to keep AND access the
>children, and just kill the parent? And, if I kill a children window,
>will that also kill the parent?

Why don't you simply start a new instance (window) of kate and open a
few tabs, all old PIDs do not change, so the new PIDs are all related to
the new Kate Window and it's tabs. With wmctrl check the PID of the
window, then kill just the PID of a tab for testing purpose. This would
have no impact to your other Kate windows and you could do tests.

Btw. whgy didn't you simply kill all Kate instances in the meantime and
reopened them again?

On Wed, 30 Dec 2015 19:07:32 -0800, rikona wrote:
>Tuesday, December 29, 2015, 9:02:30 PM, Keith wrote:
>> You can use the command: xkill
>Does this work at a 'window' level?

I doubt that a GUI tool is able to select a tab of a window that isn't
responsive, IOW if xkill should work, then it most likely would kill
the complete window.

However, I also doubt that killing the PID of a tab by command line
will make the windows with the rest of the tabs responsive again.

On Wed, 30 Dec 2015 21:13:41 -0800, Keith wrote:
>Yes this works at the window level. All instances of kate that are
>running will be killed when you use xkill so save your work in other
>windows first.

With "instances" you mean tabs, but assumed you run two or more windows
of Kate, then it would just kill one window, right?