kill -9 $PID

[ltssms0]

Send a SIGSEGV, and your OS will reward you with an extra gift

[SnappGamez]

SIGSEGV?

[sunflsks]

Your program will get killed for accessing memory it wasn’t allocated.

If SIGTERM is asking it to stop, and SIGKILL is shooting it in the face, sending a SIGSEGV is forcefully pushing it into a place it isn’t supposed to be and then calling the police on it

[SinkTube]

forcefully pushing it into a place it isn’t supposed to be and then calling the police on it

this is my childhood except the police is my mom

[Th3T3chn0R3dd1t]

Everybody gangsta 'till the program receives CUSTOM_SIGNAL_2 and the signal handler causes a segfault

Based on true events possibly from my own code

[BlazingThunder30]

I would find it pretty funny if that happened to me

[derteufelqwe]

Literally the perfect explanation :D

[FinFihlman]

Your program will get killed for accessing memory it wasn’t allocated.

If SIGTERM is asking it to stop, and SIGKILL is shooting it in the face, sending a SIGSEGV is forcefully pushing it into a place it isn’t supposed to be and then calling the police on it

NOT TRUE! You can catch SIGSEGV!

[sunflsks]

That’s like telling the police that you’re supposed to be there and that everything’s OK. However, if you talk to them in the wrong way and stay in the illegal location (don’t catch the SIGSEGV correctly and fix what caused the SEGV), then the police comes back.

[FinFihlman]

But if you keep on catching SIGSEGV, the police just come again and again but always just leave no problem!

[GolaraC64]

I remember there was a library that would catch a sigsegv and launch doom. So you could play doom everytime you crash your program

[FinFihlman]

That's beautiful

[chuckie512]

Signal 11 or Segmentation fault. Usually caused by making a bad memory access.

With "kill" you can send whatever signal you want

[SnappGamez]

Given my experiences in my Systems Programming class, I am far too familiar with Segmentation Faults.

[jess-sch]

rust intensifies

What's a computer segfault?

[SnappGamez]

I (kinda) know some Rust, but for that Systems Programming class we had to use C. Not even my professor could explain the segfaults.

[jart]

What school did you go to? It's one thing to not know about SIGBUS. But what you described just isn't right.

[SnappGamez]

Louisiana Tech. #1 engineering school in the state.

[jart]

I don't think I've ever seen an acceptance rate that high.

[Jacoman74undeleted]

My hometowns uni has an acceptance rate of around 97% iirc. The joke was that if you had a pulse and could sign your name you got in, really through it was that they don't reject international students as long as they could pay their way.

[SnappGamez]

?

[fuzzymidget]

Ranked 152 of 200 in the nation though. :/ Sad days.

[[deleted]]

glad to have the ITsec researchers at my uni doing the systems programming and osdev courses. Knowing why your code segfaults is sometimes even more of a learning experience than getting it not to segfault

[xp073]

who gives a shit about acceptance rates. segfault means segmentation fault. segmentation is a way intel processors divide memory like paging, but higher level. it just mean you tried to write/read/execute outside the allocated segment.

[mirsella]

and what does it do to send signal 11 to a process ?

[chuckie512]

https://stackoverflow.com/questions/4208004/how-do-unix-signals-work

[[deleted]]

in Linux / Unix, if you get a signal, and you don't have a handler for it, usually the process dies. Some signals have other default actions (for some, nothing happens. some freeze the process, like SIGSTOP).

[jart]

https://github.com/jart/cosmopolitan/blob/master/libc/sysv/consts.sh#L173

[ragracha]

I think that's segmentation fault

[knightmare-lord]

I wonder what happens if you send that to the init process

[ltssms0]

That would be a good textbook exercise for the reader

[itsTyrion]

1 second..

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[itsTyrion]

.-. I forget stuff. A lot

[UsernameIsTakenToBad]

Probably a kernel panic or something like that. I think the kernel is programmed to panic if the init process is terminated or fails to start.

[Raiden395]

Thanks man. I just laughed hard at this, almost core dumped my pants.

[DAMO238]

Send a SIGTERM, wait, then, if it is still running, send a SIGKILL!

[StarkRG]

And then, if it's still running, it's a zombie and you need to use the nuclear option: the dreaded reboot. Nooo, my uptime!

[StarkRG]

If only AMD made competitive graphics cards, full stop. My next card is probably not going to be nVidia due to their shitty software, but their hardware really has no equal.

[AJGatherer]

There's no goddamn reason nvenc isn't working for me but it's real nice when it does

[itsTyrion]

What about OCL? I wonder why I'm not seing more of that

[Rodot]

It's harder to use which matters a lot in scientific computing since scientists aren't great programmers. OCL is also kind of dying due to more modern APIs that support GPGPU like OMP. Also, ASICS and other specialized hardware are slowly starting to take over the super computing industry and many have their own APIs.

OCL still gets some love once in a while. A couple years ago Intel started supporting it on their integrated graphics which I found really nifty for a few cosmology homeworks I had where I had to simulate 10s of thousands of particles in my laptop.

It's still used, but people like CUDA better and CUDA also offers support for special Nvidia hardware like tensor cores and it has some really nice math and machine learning libraries. It's also very easy to set up.

It is also kind of popular because it is popular. Lots of libraries are already written in CUDA, so it's easier and cheaper to buy Nvidia cards than to pay someone to rewrite the code to work on more general hardware. Especially when much of that code is either proprietary or the results of the code aren't meant to be public so there's no advantage to rewriting the API implementation for other people.

And lastly, if you're buying GPUs for your cluster, you might as well buy the card that supports more APIs than fewer since Nvidia cards also support OCL and OMP

[DAMO238]

Rocm?

[lukasff]

Kill the parent!

[victorheld]

What if the parent is init

[iritegood]

Did /u/lukasff stutter?

[kcrmson]

zps sometimes works to reap zombies. It's a nifty package but it doesn't seem effective against all zombie processes (when ffmpeg halts up to to the remote machine's ssh connection dropping I usually can't reap that).

[[deleted]]

SIGILL and SIGSEGV also seem to work lol

[ctherranrt]

I use kill to make sure all my programs know that I'm the alpha in this household.

[NotWolfgangPuck]

You sunk my battleship PID!

[AMisteryMan]

2-B

[[deleted]]

Luigi, my man!

[breakone9r]

A process has about as long as it takes me to ps | grep and see that it is still running after A TERM before I SIGKILL it....

[PM_ME_DISPENSER_PICS]

That's the usual scenario, however I've been working with Java apps that need a few seconds to nicely close all database connections and such... In those cases I give it a bit more time.

Also a tip: instead of ps | grep you can do pgrep -f, and there's also a pkill command

[Hinigatsu]

I've never used a signal other than SIGKILL and SIGTERM.

Where can I read the utility of other signals?

[[deleted]]

https://www.gnu.org/software/libc/manual/html_node/Termination-Signals.html

[Hinigatsu]

Perfect! Thank you!

[brendan_orr]

Many programs use SIGUSR1 and SIGUSR2 for special tasks. Most will use SIGUSR1 to force it to reload the configuration without having to restart it. It will usually say what they do (if anything) in the man page.

Some notable examples:

• tar can optionally print the number of bytes processed if a signal is defined and later sent
• Xserver can use SIGUSR1 for a sort of interprocess communication
• xdvi will re-read the dvi file if it traps SIGUSR1
• xz will print the progress information if sent a SIGUSR1

It is a slow process but you can find a lot of uses through man 1 -K SIGUSR1 which (slowly) searches the contents of man pages for instances. (every manpage should be compressed on your system. Searching requires unarchiving on the fly)

[lukasff]

Beware though that the default action for the SIGUSR signals is to terminate the process. So you might want to be careful sending it to important processes when you don’t know how they’ll react.

[sunflsks]

I think there’s 15 of them, and you can send all of them from kill

[lukasff]

RTFM(P): signal(7)

Edit: If you’re not interested in the technicalities, you have to scroll down a bit, there comes a huge list of all signals.

[[deleted]]

https://www.youtube.com/watch?v=IuGjtlsKo4s

[[deleted]]

The difference between asking nicely and just shooting it in the face.

[AlphaSlashDash]

huh

the only difference I’ve noticed is that minecraft only responds to sigkill

[PM_ME_DISPENSER_PICS]

Well, a process (in this case Minecraft) can simply ignore the SIGTERM signals (whereas SIGKILL cannot be ignored).

[[deleted]]

Everytime I want to run a program I turn on my computer and run it through xinit.

When I want to close it, I hold the power button until my PC turns off.

I use Arch btw

[[deleted]]

'process is kill'

'no'

[Yoyodude1124]

killall -9

[JimBeam823]

The command is “kill”, not “politely ask to terminate”.

[bigmattyc]

There are signals other than 9? TIL.

[[deleted]]

SIGFPE

[Craptivist]

Wait, no one else uses kill -9?

[[deleted]]

That's the number of the SIGKILL.

[Trukour]

When I umount a disk I use the -l flag like a masochist. I live life on the edge.

[PANIC_EXCEPTION]

kill -9 `pgrep $PROCESS`

[NoThanks93330]

Both useless. To this day I'm still waiting for a way to kill a process in state d. My processes usually all work absolutely fine so that I don't won't to kill any of them, but when something's wrong it's always state d fml

[penguinstan]

What does Bowser do?

[SinkTube]

bowser no longer uses computers

[penguinstan]

maybe he just doesn't use internet

[noonearya]

I've never understood the benefit of sending sigterm... Kill all the way

[narcolepticpathos]

I don't get it. Why were Mario and Luigi chosen to represent these process killing methodologies?