For testing purposes I have this shell script  #!/bin/bash echo $$ find / &gt;/dev/null 2&gt;&amp;1   Running this from an interactive terminal, ctrl+c will terminate bash, and the find command.  $ ./test-k.sh 13227 &lt;Ctrl+C&gt; $ ps -ef |grep find $   Running it in the background, and killing the shell only will orphan the commands running in the script.   $ ./test-k.sh &amp; [1] 13231 13231 $ kill 13231 $ ps -ef |grep find nos 13232     1  3 17:09 pts/5    00:00:00 find / $   I want this shell script to terminate all its child processes when it exits regardless of how it's called. It'll eventually be started from a python and java application - and some form of cleanup is needed when the script exits - any options I should look into or any way to rewrite the script to clean itself up on exit?
I want to kill a whole process tree.  What is the best way to do this using any common scripting languages? I am looking for a simple solution.
Gameplay programmers write game code, but so do game designers and developers. Where is the line drawn? What skills do gameplay programmers use that game designers or developers do not? A inequality proposed at Zhautykov Olympiad 2008 An inequality proposed at Zhautykov Olympiad 2008.     Let be $a,b,c &gt;0$ with $abc=1$. Prove that:    $$\sum_{\mathrm{cyc}}{\frac{1}{(a+b)b}} \geq \frac{3}{2}.$$   Set $a=\frac{x}{y}$, $b=\frac{y}{z}$, $c=\frac{z}{x}$.   Our inequality becomes: $$\sum_{\mathrm{cyc}}{\frac{z^2}{zx+y^2}} \geq \frac{3}{2}.$$  Now we use that: $z^2+x^2 \geq 2zx.$ $$\sum_{\mathrm{cyc}}{\frac{z^2}{zx+y^2}} \geq \sum_{\mathrm{cyc}}{\frac{2z^2}{z^2+x^2+2y^2}} \geq \frac{3}{2}.$$  Now applying Cauchy-Schwarz we obtain the desired result.  What I wrote can be found on this link: . But now, I don't know how to apply Cauchy-Schwarz.   Thanks:) Subsample of a random sample: random sample? Let's say you have a large random sample of soccer players in Europe but you are only interested in what happens in Spain. Could you reduce your sample to players in Spain and still call it a random sample (but of a different population)? If not, how would you call that subsample and which specific precautions should you take to be able to make inferences on the population of spanish soccer players?  My feeling is that using that subsample would be fine as long as it is large enough, but maybe I am missing something. On-screen keyboard popping up whenever I touch screen I'm in 17.10. Whenever I touch the screen, whether to change windows/apps, scroll within a browser, or press a button, the stupid little keyboard pops up in the bottom left corner.  I have never left Screen Keyboard enabled in Universal Access, but if I toggle it on, that's the same keyboard popping up in the bottom left corner.    In this screenshot, I'm simply touching the screen in a full-screen youtube video. You can see the menu pop up on the right, under the point where I'm touching.  I don't have a before pic, but it was similar look/color keyboard, but it was smaller, maybe half as wide, and only in the bottom left section of the screen, as opposed to stretching across the entire width. This change from little left-hand keyboard to full-width keyboard happened after following @pomsky 's advice below.    This is a . You can mark yourself affected by it to hopefully increase its received attention. How to redirect stderr and stdout to different files and also display in terminal? I want to see the output of a command in the terminal as if there was no redirection.  Also, stderr needs to be redirected to err.log and stdout needs to be redirected to stdout.log.  It would be nice to also have the exact copy of what is shown in terminal, i.e. errors printed as and when it occurs, in a separate file: stdouterr.log. Saving Arduino sensor data to a text file Replaced wrong car in garage in GTA Online Ever since adding an iTunes gift card to my account, I'm getting verification requests like crazy. I can't even download free apps. It takes me to my payment info and when I try to select none, I continually get a message under the payment info that says "you must verify your payment info to continue"  I don't want a credit card on file and would really like the none option to work. My ID shows I still have iTunes credit. Is there any cryptographic algorithm immune to side channel attacks based on scan chain? In VLSI point of view. Choosing C++ debugger on linux What is "it" in the following sentence: It is clear that Bob likes doughnuts I am very confused. Unless I am mistaken, I know "it" has to be a noun of some sort, but I am unable to figure out what noun "it" is referring to.   What is "it" in the following sentence:      It is clear that Bob likes doughnuts.   Heres another couple of examples:     It is impossible to fly. Good way to make \textcircled numbers? This question led to a new package:      I'm trying to make some good-looking numbers in a circle, using the simple command:  \textcircled{1}   However, the circle is misaligned vertically with the number, and look a bit sloppy:    Any suggestions how can I adjust the vertical alignment so that the numbers look more centered w.r.t to the circles? Or, if that's not an option, what other ways to achieve the same results are possible?  I will use those only for numbers, and in very few places, so manual adjustment per glyph is an option.  I'm using pdfLaTeX with Computer Modern, if that matters. $\operatorname{Supp}(M)=V(\operatorname{Ann}M)$ if $M$ is finitely generated Why did skilled wizards use He-Who-Must-Not-Be-Named? Pursuant to , it's plausible that the typical witch or wizard would use 'He-Who-Must-Not-Be-Named' (if they assume Taboo Spell is intact after death of Voldemort). But, why would the Aurors and those in the Ministry of Magic (who had first rate protection) also use it? Even Snape (the Half-Blood Prince) hesitated to say 'Voldemort', and he was under the protection of Dumbledore, Dumbledore being the only wizard Voldemort ever feared.  What was the point of the Death Eaters being scared to say 'Voldemort' when, ostensibly, Voldemort wasn't even alive? Yes, it's true that some believed Voldemort would return, but, at the time, it was just that -- a belief. Were people scared that the Death Eaters might give a list of all those who used Voldemort's name to Voldemort upon his return? Is the word tenfold a misnomer? How can I set up dual monitors with nVidia? How to get access to USB-storage from an application installed as Snap? I have Ubuntu 18.04 LTS installed. I inserted USB-flash to my laptop. It was automounted to /media/username/DISKLABEL and opened in Nautilus. I can read and write objects to it. How can I access it from the application, which is installed as Snap? I tried snaps of the following applications such as gedit, arduino-mhall119, organize-my-files. All them show me errors if I navigate to /media folder:    Could not read the contents of Media Error opening the directory of '/media': permission denied  Output of active Snap  is below: $ snap interfaces  | grep -v &quot;.*-$&quot; Slot                             Plug :browser-support                 organize-my-files :core-support                    core:core-support-plug :cups-control                    gedit :desktop                         gedit,organize-my-files :desktop-legacy                  gedit,organize-my-files :gsettings                       gedit,organize-my-files :home                            arduino-mhall119,gedit,organize-my-files :network                         arduino-mhall119,gedit,organize-my-files,pulsemixer :opengl                          organize-my-files :pulseaudio                      organize-my-files,pulsemixer :unity7                          arduino-mhall119,gedit,organize-my-files :wayland                         gedit :x11                             arduino-mhall119,organize-my-files,pulsemixer gnome-3-26-1604:gnome-3-26-1604  gedit gtk-common-themes:gtk3-themes    gedit gtk-common-themes:icon-themes    gedit gtk-common-themes:sound-themes   gedit -                                arduino-mhall119:serial-port -                                gedit:avahi-observe -                                gedit:mount-observe  Updates:  connecting mount-observe to Gedit with snap connect gedit:mount-observe does not help. it seems that we need special Snap with support of  interface. How to Deserialize XML document One of my Fellows asked me whether total induction is applicable to real numbers, too ( or at least all real numbers ≥ 0) . We only used that for natural numbers so far.  Of course you have to change some things in the inductive step, when you want to use it on real numbers.  I guess that using induction on real numbers isn't really possible, since $[r,r+\epsilon]$ with $\epsilon > 0$, $r \in \mathbb R$ is never empty.  Can you either give a good reason, why it isn't possible or provide an example where it is used? The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead