Taskkill question

Does Taskkill do a graceful shutdown or brute force?

T wrote in :

Does Taskkill do a graceful shutdown or brute force?

I am assuming you are refering to the task kill that is part of Task
Manager. If so, the sends a 'die' signal to the task, which is supposed to
have an overriding section of code that will terminate the task as soon as
possible. Usually it works, but I have had a few times when a task was
apparently really fubarred where it didn't work.

On 7/5/19 7:06 PM, lonelydad wrote:
T wrote in :

Does Taskkill do a graceful shutdown or brute force?

I am assuming you are refering to the task kill that is part of Task
Manager. If so, the sends a 'die' signal to the task, which is supposed to
have an overriding section of code that will terminate the task as soon as
possible. Usually it works, but I have had a few times when a task was
apparently really fubarred where it didn't work.


I am talking about the command line:

Taskkill /IM chrome.exe /F

I wonder if it also has a "die" function. "/F"
may be "force", in which case

Taskkill /IM chrome.exe
wait five seconds
Taskkill /IM chrome.exe /F

I am i Linux right now, so I can't look it up.

On 7/5/19 7:28 PM, T wrote:
IÂ*amÂ*iÂ*LinuxÂ*rightÂ*now,Â*soÂ*IÂ*can'tÂ*lookÂ* itÂ*up.

Well DuckDuckGo has it:

https://docs.microsoft.com/en-us/pre...725602(v=ws.10)

/f Specifies that processes be forcefully terminated.

So first try, leave off the "/f".

T wrote:
On 7/5/19 7:06 PM, lonelydad wrote:
T wrote in :

Does Taskkill do a graceful shutdown or brute force?

I am assuming you are refering to the task kill that is part of Task
Manager. If so, the sends a 'die' signal to the task, which is
supposed to
have an overriding section of code that will terminate the task as
soon as
possible. Usually it works, but I have had a few times when a task was
apparently really fubarred where it didn't work.


I am talking about the command line:

Taskkill /IM chrome.exe /F

I wonder if it also has a "die" function. "/F"
may be "force", in which case

Taskkill /IM chrome.exe
wait five seconds
Taskkill /IM chrome.exe /F

I am i Linux right now, so I can't look it up.

What happened to your VM ?

Windows 10 doesn't have to be "activated" to be useful.
An unactivated copy, only the Personalization portion
of the Setup wheel is blocked.

You can get a Windows 10 for "quick jobs" here.

https://developer.microsoft.com/en-u...dge/tools/vms/

A VM is a 4 to 5GB download. If the VM were to refuse to
run, simply delete the VM and unpack a new copy. (On
VirtualBox, the appliance file is a 5GB .ova file and
you keep the original download so you can unpack it
over and over again.)

Using your VM, you could

taskkill /?

to get more info.

And the time to collect those VMs, was around 5 years ago,
so you could get "a complete set".

Paul

T wrote:

Does Taskkill do a graceful shutdown or brute force?

With the /f switch, taskkill sends a shutdown request to the process,
similar to how a shutdown sends a similar request. Some apps will
continue to refuse to respond, so you have to add /f switch to brute
force their kill.

MS Outlook (the local program, not the outlook.com web site) has no
command-line switch to tell it to gracefully shutdown. When doing
backups, and if your backup program doesn't support VSC (Volume Shadow
Copy), then it cannot read locked/inuse files, and that would include
Outlook's .pst file while Outlook is running. You could try to use
"taskkill.exe /f /im outlook.exe" to kill off MS Outlook before the
backup job begins, but smashing Outlook means it doesn't get to save any
changes to its PST file, and that can lead to corrupt of the database
file. So, you get a backup program that supports VSC, or you forego
including Outlook's PST file in your backups (if you leave Outlook
loaded 24x7).

First the process must recognize the shutdown request. If it ignores
the request, you're stuck having to kill the process. Even if it does
recognize the request, it may not honor it, so you have to kill it.
After recognizing the request and branching to its exit code, the exit
could take too long, so the OS sees the process as unresponsive and will
kill it (after prompting you). The response wait time is configurable
in the registry. I'd have to go look it up again, but an online search
on "windows process shutdown wait time" will probably find the registry
edit(s).

https://www.google.com/search?q=wind...down+wait+time

found many, like:

https://www.howtogeek.com/282062/con...s-at-shutdown/

I'm guessing the shutdown wait times also apply to when you request
individual processes to exit. Seems something you could test by
altering the values, but you'd need to find a stubborn process that
doesn't recognize or doesn't honor the request or takes way too long to
run its cleanup & exit code.

On 7/5/19 9:40 PM, Paul wrote:
WhatÂ*happenedÂ*toÂ*yourÂ*VMÂ*?

Duck Duck go was quicker. I had spaced on it
and forgot I could do that.

On 7/5/19 10:14 PM, VanguardLH wrote:
T wrote:

Does Taskkill do a graceful shutdown or brute force?

With the /f switch, taskkill sends a shutdown request to the process,
similar to how a shutdown sends a similar request. Some apps will
continue to refuse to respond, so you have to add /f switch to brute
force their kill.

MS Outlook (the local program, not the outlook.com web site) has no
command-line switch to tell it to gracefully shutdown. When doing
backups, and if your backup program doesn't support VSC (Volume Shadow
Copy), then it cannot read locked/inuse files, and that would include
Outlook's .pst file while Outlook is running. You could try to use
"taskkill.exe /f /im outlook.exe" to kill off MS Outlook before the
backup job begins, but smashing Outlook means it doesn't get to save any
changes to its PST file, and that can lead to corrupt of the database
file. So, you get a backup program that supports VSC, or you forego
including Outlook's PST file in your backups (if you leave Outlook
loaded 24x7).

First the process must recognize the shutdown request. If it ignores
the request, you're stuck having to kill the process. Even if it does
recognize the request, it may not honor it, so you have to kill it.
After recognizing the request and branching to its exit code, the exit
could take too long, so the OS sees the process as unresponsive and will
kill it (after prompting you). The response wait time is configurable
in the registry. I'd have to go look it up again, but an online search
on "windows process shutdown wait time" will probably find the registry
edit(s).

https://www.google.com/search?q=wind...down+wait+time

found many, like:

https://www.howtogeek.com/282062/con...s-at-shutdown/

I'm guessing the shutdown wait times also apply to when you request
individual processes to exit. Seems something you could test by
altering the values, but you'd need to find a stubborn process that
doesn't recognize or doesn't honor the request or takes way too long to
run its cleanup & exit code.



Thank you!

I was going to taskkill without the /f, wait
five seconds (maybe 10), then do it again with
the "/f".

On 7/5/19 6:11 PM, T wrote:
Does Taskkill do a graceful shutdown or brute force?


Follow up:

Set this off at 05:00

TaskKillAndReboot.bat
echo off

:: kill off select running tasks that do not respond to Volume Shadow
copy Service (VSS)

msg * Killing off selective tasks that are not Volume Shadow copy
Service (VSS) Friendly and rebooting
echo Killing off selective tasks that are not Volume Shadow copy Service
(VSS) Friendly
echo.

echo Asking nicely...
taskkill.exe /IM chrome.exe
taskkill.exe /IM brave.exe
taskkill.exe /IM firefox.exe
taskkill.exe /IM thunderbird.exe
taskkill.exe /IM QBW32.EXE
echo.
echo.

echo Sleeping for 10 seconds
C:\NtUtil\sleep 10s /quiet

echo Cutting their legs off
taskkill.exe /IM chrome.exe /f
taskkill.exe /IM brave.exe /f
taskkill.exe /IM firefox.exe /f
taskkill.exe /IM thunderbird.exe /f
taskkill.exe /IM QBW32.EXE /f
echo.

echo Sleeping for 10 seconds
C:\NtUtil\sleep 10s /quiet

shutdown.exe /r /f /t 15
/TaskKillAndReboot.bat

T wrote:
On 7/5/19 6:11 PM, T wrote:
Does Taskkill do a graceful shutdown or brute force?


Follow up:

Set this off at 05:00

TaskKillAndReboot.bat
echo off

:: kill off select running tasks that do not respond to Volume Shadow
copy Service (VSS)

msg * Killing off selective tasks that are not Volume Shadow copy
Service (VSS) Friendly and rebooting
echo Killing off selective tasks that are not Volume Shadow copy Service
(VSS) Friendly
echo.

echo Asking nicely...
taskkill.exe /IM chrome.exe
taskkill.exe /IM brave.exe
taskkill.exe /IM firefox.exe
taskkill.exe /IM thunderbird.exe
taskkill.exe /IM QBW32.EXE
echo.
echo.

echo Sleeping for 10 seconds
C:\NtUtil\sleep 10s /quiet

echo Cutting their legs off
taskkill.exe /IM chrome.exe /f
taskkill.exe /IM brave.exe /f
taskkill.exe /IM firefox.exe /f
taskkill.exe /IM thunderbird.exe /f
taskkill.exe /IM QBW32.EXE /f
echo.

echo Sleeping for 10 seconds
C:\NtUtil\sleep 10s /quiet

shutdown.exe /r /f /t 15
/TaskKillAndReboot.bat


You know, one thing that bothers me a bit, is
I got my Macrium backup finished, and it looks
like it didn't have a problem taking a snapshot
of "places.sqlite" while Firefox was open
to a news web page (the kind that puts up
fresh advertising every five seconds).

I found an academic paper, that claimed (somehow!)
you could use two or more VSS shadows, and do a
"logical OR" to gather sectors, and this somehow
makes it possible to snapshot files like places.sqlite.

I don't really see any evidence Macrium is doing that.

There is more to this than meets the eye.

Anyway, here is a poorly formatted short article
from some guys in India, who claim to have added
a VSS wart to the side of sqlite3.exe.

http://www.digitalxplore.org/up_proc...1689512-14.pdf

What's the problem ? No download link for any sample code.
I don't know what the purpose of writing a paper is, if
there's no sample.

Paul

On 7/8/19 10:03 PM, Paul wrote:
T wrote:
On 7/5/19 6:11 PM, T wrote:
Does Taskkill do a graceful shutdown or brute force?


Follow up:

Set this off at 05:00

TaskKillAndReboot.bat
echo off

:: kill off select running tasks that do not respond to Volume Shadow
copy Service (VSS)

msg *Â* Killing off selective tasks that are not Volume Shadow copy
Service (VSS) Friendly and rebooting
echo Killing off selective tasks that are not Volume Shadow copy
Service (VSS) Friendly
echo.

echo Asking nicely...
taskkill.exe /IM chrome.exe
taskkill.exe /IM brave.exe
taskkill.exe /IM firefox.exe
taskkill.exe /IM thunderbird.exe
taskkill.exe /IM QBW32.EXE
echo.
echo.

echo Sleeping for 10 seconds
C:\NtUtil\sleep 10s /quiet

echo Cutting their legs off
taskkill.exe /IM chrome.exeÂ*Â*Â*Â*Â* /f
taskkill.exe /IM brave.exeÂ*Â*Â*Â*Â*Â* /f
taskkill.exe /IM firefox.exeÂ*Â*Â*Â* /f
taskkill.exe /IM thunderbird.exe /f
taskkill.exe /IM QBW32.EXEÂ*Â*Â*Â*Â*Â* /f
echo.

echo Sleeping for 10 seconds
C:\NtUtil\sleep 10s /quiet

shutdown.exe /r /f /t 15
/TaskKillAndReboot.bat


You know, one thing that bothers me a bit, is
I got my Macrium backup finished, and it looks
like it didn't have a problem taking a snapshot
of "places.sqlite" while Firefox was open
to a news web page (the kind that puts up
fresh advertising every five seconds).

I found an academic paper, that claimed (somehow!)
you could use two or more VSS shadows, and do a
"logical OR" to gather sectors, and this somehow
makes it possible to snapshot files like places.sqlite.

I don't really see any evidence Macrium is doing that.

There is moreÂ* to this than meets the eye.

Anyway, here is a poorly formatted short article
from some guys in India, who claim to have added
a VSS wart to the side of sqlite3.exe.

http://www.digitalxplore.org/up_proc...1689512-14.pdf

What's the problem ? No download link for any sample code.
I don't know what the purpose of writing a paper is, if
there's no sample.

Â*Â* Paul


My solution was just to shut them off. Quick Books is a
particular pain in the ass to backup

T wrote:

...
C:\NtUtil\sleep 10s /quiet
...

Windows 7, and later, has its own timeout command to let you pause the
script for a specified time. Run "timeout /?" for help. Just something
to reduce dependence of your batch script to 3rd party software.

If you still want to use a 3rd party program, I would test it exists
before trying to use it. If it doesn't exist, do you really want to run
the rest of the script? If the 3rd party program sets the errorlevel,
you could test if it ran okay instead of pre-testing it exists.

Note that when you kill Firefox, it will attempt to reload the prior
tabs unless you disable its recovery. Google Chrome will bitch on its
next load that it wasn't exited properly and offers to reload the prior
tabs. Hell, just using its own "X" exit button at the right end of the
titlebar sometimes makes Chrome think it wasn't closed properly. For
Chrome, there is no option to disable recovery and the only clumsy
method I've seen is to edit some config file to eradicate the flag that
makes Chrome think it had a dirty exit ("exited_cleanly":false).

In fact, with both web browsers, I've seen where, for example, a
corrupted cookie or tab history prevented loading the web browser. It
would crash when loaded. The solution was to load it in its safe mode,
exit, and reload.

I'd use "taskkill.exe /im processname" to see which web browser will
run their exit code when they are requested to unload. Are you sure any
of them reject or don't honor that request, so you don't have to smash
them to get rid of their processes? Smashing a process that has open
files can lead to corruption of those files.

When Windows shuts down, it gives a default 20 seconds (can be changed
in the registry) for a process to respond. Your timeout of 20 seconds
might not be reliably long enough. Microsoft is probably being
generous, but they've also probably had more statistics as to when the
vast majority of processes would unload when requested.

I haven't used taskkill.exe for awhile, but I would expect it to return
a status code. While stopping services immediately returns a status
despite the service may take awhile to unload (the shutdown request is
asynchronous between when the return status is returned for the request
and when the service actually stops). If taskkill.exe returns a zero
status, seems you could test on that using:

@echo off
cls
echo Kill any existing processes for the following web browsers:
echo - Google Chrome
echo - Mozilla Firefox
...
echo.
echo Attempting soft request to stop the web browsers ...
set chrmflag=1
set fxflag=1
...
taskkill.exe /im chrome.exe
if "%errorlevel%" EQU "0" do (
echo Google Chrome exited.
set chrmflag=0
)
taskkill.exe /im firefox.exe
if "%errorlevel%" EQU "0" do (
echo - Mozilla Firefox exited.
set fxflag=0
)
....
set /a flags=%chrmflag%+%fxflag%+...
if %flags% EQU 0 do (
echo All web browsers unloaded.
goto EndBatch
)

echo.
echo Some did not exit. Force unload on remaining processes ...
for /L %i in (1,1,24) do (
if "%chrmflag%" NEQ "0" taskkill.exe /im chrome.exe /f
if "%errorlevel%" EQU "0" sdo (
echo Google Chrome exited.
set chrmflag=0
)
if "%fxflag%" NEQ "0" taskkill.exe /im firefox.exe /f
if "%errorlevel%" EQU "0" do (
echo Mozilla Firefox exited.
set fxflag=0
)
...
set /a flags=%chrmflag%+%fxflag%+...
if %flags% EQU 0 goto EndBatch
echo ... wait 5 seconds ...
timeout /t 5
)

echo ERROR! The following process(es) refused to exit after 120 seconds:
if "%chrmflag%" NEQ "0" echo chrome.exe
if "%"fxflag%" NEQ "0" echo firefox.exe
...
echo Hit a key to exit batch script ...
pause nul

:EndBatch
echo -DONE-
echo.

Since taskkill is synchronous (its return value immediately reflects
whether or not the process got killed or not), you grab its return value
(since errorlevel get stepped on by a subsequent taskkill). You add up
all the errorlevels. If zero, all were successful, so there's no point
to wait any longer or to use /f with taskkill. When using /f, there's
no point in retrying a force kill if the process managed to exit in the
next iteration of the for-loop, nor even in the 1st iteration for any
processes that did exit without using /f. The timeout of each iteration
is just 5 seconds, so any that close sooner than the 2-minute total
expiration (up to 24 iteration with each at 5 seconds = 120 seconds)
don't bother getting retried with /f. If all taskkill /f return a zero
status, no point in running any remaining iterations of the for-loop.

Instead of waiting 20 (or 30) seconds for all taskkill /f to complete,
you only run taskkill /f on those processes that haven't yet exited, and
wait only 5 seconds on each iteration. You might wait 0 seconds, 5
seconds, or up to 120 seconds for /f to work.

If after 2 minutes at 5-second intervals one, or more, processes still
have refused to unload, you list those that are stuck. That's assuming
someone is watching the console window whereing the batch script runs.

I find trying to remember the priority of various errorlevel values and
trying to test from top down in value a nuisance, so I just use
errorlevel as a string against which to test for a value.

The above batch script is off the top of my head. Probably needs some
debugging.

Oh, remember that taskkill needs elevated privileges. You cannot alter
the properties for a .bat file to elevate its privileges. You can
elevate a shortcut that runs the .bat file, or when an event in Task
Scheduler. Without elevated privs, all the taskkill commands will fail.

Paul wrote:

You know, one thing that bothers me a bit, is I got my Macrium backup
finished, and it looks like it didn't have a problem taking a
snapshot of "places.sqlite" while Firefox was open to a news web page
(the kind that puts up fresh advertising every five seconds).

As I replied to Slootweg in T's other thread ("places.sqlint read
timeout"), SQLite has a CLI where you can issue commands to it to
quiesce its database during a backup; however, my guess is the backup
program would need to create an ODBC driver to issue API calls to
SQLite. VSS isn't needed *if* the backup program is SQLite aware.

On 7/9/19 3:50 AM, VanguardLH wrote:
Oh, remember that taskkill needs elevated privileges. You cannot alter
the properties for a .bat file to elevate its privileges. You can
elevate a shortcut that runs the .bat file, or when an event in Task
Scheduler. Without elevated privs, all the taskkill commands will fail.


I tested it by opening Firefox, Chrome, Brave, and Thunderbird.
Closed all four without elevated privileges.

Shutdown /f /r /t 00 also ran fine without elevated privileges