SSH session drops - Does the command continue executing?
Does getting disconnected from an SSH session kill your programs?
What are the most downvoted questions and answers on Stack Overflow, Server Fault, Meta, and Super User history to date?  Similarly, what are the most upvoted questions and answers on SO, SF, Meta, and SU to date? My months and days in my File Manager are in German, how do I change that? On the photo you see 'Dez' : It means Dezember (German for December). I also saw one day Mittwoch (German for Wednesday). How do I change that German issue? This is only my File Manager and not completly but partially. Weird. Can I view a list of my "great comments", perhaps in my profile? I'm a little surprised no one asked this yet, but why isn't it possible to show your comments in descending order of "great comment" votes it has received? You can do this with upvotes on questions and answers, and since I think comments are the third major activity on SO, I'd like to view them. Even if you couldn't order them, it should at least show the number of votes on the activity#comments page of your profile... What exactly is an environment variable? How does mission progress work in multiplayer? Proof if $a \vec v = 0$ then $a = 0$ or $\vec v = 0$ I'm kicking myself over this one, but I just can't seem to make the argument rigorous. From Axler's Linear Algebra Done Right:  for a vector space $V$ with an underlying field $F$:  Take an element $a$ from $F$ and $\vec{v}$ from $V$. $a\vec{v}=\vec{0}\implies a=0 $ or $ \vec{v}=\vec{0}$  After only being able to come up with half of a direct proof, I tried doing this by proving the contrapositive $a\neq 0 \wedge \vec{v} \neq \vec{0} \implies a\vec{v}\neq \vec{0}$  Say $a\vec{v}=\vec{u}$. Since $a$ is non-zero, we can divide both sides by $a$.  $$\vec{v}=\frac 1 a \vec{u}$$  If $\vec{u}$ were $\vec{0}$ then by  $$\frac 1 a \vec{0}=\frac 1 a (\vec{0}+\vec{0})\implies\frac 1 a \vec{0}=\vec{0}$$ $v$ would be $0$ as well. Since it isn't by assumption, $\frac 1 a \vec{u}$ cannot be zero and so $\vec{u}$ cannot be as well.   Is this fully rigorous? It seems like a very simple question, but I'm not sure about it. Namely, the last step of $\frac 1 a \vec{u}\neq 0 \implies \vec{u}\neq 0$ doesn't seem obvious. I think I need to use the $1\vec{v}=\vec{v}$ axiom, but I'm not sure how.  Is there a more direct proof? This whole contrapositive business seems a bit clunky for something so simple. Is fractional scaling ( ) available in 18.04 LTS yet? I am waiting until this is available before I install. Does Windows 7 allow auto-login with a stored password, like TweakUI did? The TweakUI powertoy for Windows XP had an option to auto-login. It stored your password and did the login for you. This was useful, since you kept password protection, but had login programs loaded when you first booted.  When you switched users or hibernated, it would still ask for a password, which is the desired behavior.  Is there a way of doing this in Windows 7? At the end of the scene in the cemetery in GoF, the spirits who emerged from Voldemort's wand tell Harry to go grab the trophy (which, of course, was a portkey that took Harry and Cedric from the maze to the cemetery), and that the trophy portkey would take Harry back to Hogwarts.  Why would the portkey do that?  Are all the portkeys 2-way?  If possible, I would prefer as much of the answer based on canon (or JKR) as feasible SSH tunnelling with multiple dynamic port forwardings I am trying to monitor multiple JVMs running on different servers through an ssh tunnel.  Thanks to one of the UNIX gurus here, I have managed to get this running for a single server by:   Run jstatd on the target server Set up Visual VM to use 9696 as its socks proxy port. On my local PC, run:  ssh -L 2222:server1:22 bastion-host  On my local PC, run:  ssh -o port=2222 -D 9696 -L 1099:localhost:1099 localhost    This does the trick. Now when I try and tunnel to a second server I try:   On my local PC, run:  ssh -L 3333:server2:22 bastion-host  On my local PC, run:  ssh -o port=3333 -D 9696 -L 2099:localhost:1099 localhost    However, the last step complains with:  bind: Address already in use channel_setup_fwd_listener: cannot listen to port: 9696   Has anyone managed to do something similar?  Update:  The reason this is so complex is that jstatd is an RMI server application:    As with RMI applications, these register with an rmiregistry. Using rmi through a firewall requires me to use SOCKS as described here:    Unfortunately, visualvm only lets me set the SOCKS proxy port once, and the -D option won't allow me to forward the same local port to both servers... Regex to match only letters Does this need a comma? I am trying to prove the statement:  If $X\sim\mathcal{N}(0,\sigma_1^2)$ and $Y\sim\mathcal{N}(0,\sigma_2^2)$ are independent random variables, then $\frac{XY}{\sqrt{X^2+Y^2}}$ is also a Normal random variable.  For the special case $\sigma_1=\sigma_2=\sigma$ (say), we have the well-known result that $\frac{XY}{\sqrt{X^2+Y^2}}\sim\mathcal{N}\left(0,\frac{\sigma^2}{4}\right)$ whenever $X$ and $Y$ are independent $\mathcal{N}(0,\sigma^2)$ variables. In fact, it is more generally known that $\frac{XY}{\sqrt{X^2+Y^2}},\frac{X^2-Y^2}{2\sqrt{X^2+Y^2}}$ are independent $\mathcal{N}\left(0,\frac{\sigma^2}{4}\right)$ variables. A proof of the last result follows by using the transformation $(X,Y)\to(R,\Theta)\to(U,V)$ where $x=r\cos\theta,y=r\sin\theta$ and $u=\frac{r}{2}\sin(2\theta),v=\frac{r}{2}\cos(2\theta)$. Indeed, here $U=\frac{XY}{\sqrt{X^2+Y^2}}$ and $V=\frac{X^2-Y^2}{2\sqrt{X^2+Y^2}}$. I tried to imitate this proof for the problem at hand but it appears to get messy. If I haven't made any error, then for $(u,v)\in\mathbb{R}^2$ I end up with the joint density of $(U,V)$ as $$f_{U,V}(u,v)=\frac{2}{\sigma_1\sigma_2\pi}\exp\left[-\sqrt{u^2+v^2}\left(\frac{\sqrt{u^2+v^2}+v}{\sigma_1^2}+\frac{\sqrt{u^2+v^2}-v}{\sigma_2^2}\right)\right]$$ I have the multiplier $2$ above as the transformation is not one-to-one. So density of $U$ would be given by $\displaystyle \int_{\mathbb{R}}f_{U,V}(u,v)\,\mathrm{d}v$, which isn't readily evaluated. Now I am interested to know if there is a proof where I can only work with $U$ and don't have to consider some $V$ to show that $U$ is Normal. Finding the CDF of $U$ doesn't look so promising to me at the moment. I would also like to do the same for the case $\sigma_1=\sigma_2=\sigma$. That is, if $X$ and $Y$ are independent $\mathcal{N}(0,\sigma^2)$ variables then I wish to show that $Z=\frac{2XY}{\sqrt{X^2+Y^2}}\sim\mathcal{N}(0,\sigma^2)$ without using a change of variables. If somehow I can argue that $Z\stackrel{d}{=}X$, then I'm done. So two questions here, the general case and then the particular case. Related posts on Math.S.E: . . Edit. This problem is in fact due to L. Shepp as I found out in the exercises of An Introduction to Probability Theory and Its Applications (Vol. II) by Feller, alongwith a possible hint:  Surely, $U=\frac{XY}{\sqrt{X^2+Y^2}}=\frac{1}{\sqrt{\frac{1}{X^2}+\frac{1}{Y^2}}}$ and I have the density of $\frac{1}{X^2}$ at hand. Let's see what I could do now. Apart from this, a little help with the integral above is also welcome. Although elements like &lt;div&gt;s normally grow to fit their contents, using the float property can cause a startling problem for CSS newbies: If floated elements have non-floated parent elements, the parent will collapse. For example:   &lt;div&gt;   &lt;div style="float: left;"&gt;Div 1&lt;/div&gt;   &lt;div style="float: left;"&gt;Div 2&lt;/div&gt; &lt;/div&gt;    The parent div in this example will not expand to contain its floated children - it will appear to have height: 0. How do you solve this problem? I would like to create an exhaustive list of solutions here. If you're aware of cross-browser compatibility issues, please point them out. Solution 1 Float the parent.   &lt;div style="float: left;"&gt;   &lt;div style="float: left;"&gt;Div 1&lt;/div&gt;   &lt;div style="float: left;"&gt;Div 2&lt;/div&gt; &lt;/div&gt;    Pros: Semantic code. Cons: You may not always want the parent floated. Even if you do, do you float the parents' parent, and so on? Must you float every ancestor element? Solution 2 Give the parent an explicit height.   &lt;div style="height: 300px;"&gt;   &lt;div style="float: left;"&gt;Div 1&lt;/div&gt;   &lt;div style="float: left;"&gt;Div 2&lt;/div&gt; &lt;/div&gt;    Pros: Semantic code. Cons: Not flexible - if the content changes or the browser is resized, the layout will break. Solution 3 Append a &quot;spacer&quot; element inside the parent element, like this:   &lt;div&gt;   &lt;div style="float: left;"&gt;Div 1&lt;/div&gt;   &lt;div style="float: left;"&gt;Div 2&lt;/div&gt;   &lt;div class="spacer" style="clear: both;"&gt;&lt;/div&gt; &lt;/div&gt;    Pros: Straightforward to code. Cons: Not semantic; the spacer div exists only as a layout hack. Solution 4 Set parent to overflow: auto.   &lt;div style="overflow: auto;"&gt;   &lt;div style="float: left;"&gt;Div 1&lt;/div&gt;   &lt;div style="float: left;"&gt;Div 2&lt;/div&gt; &lt;/div&gt;    Pros: Doesn't require extra div. Cons: Seems like a hack - that's not the overflow property's stated purpose. Comments? Other suggestions? Is it costly to do array.length or list.count in a loop I know that in JavaScript, creating a for loop like this: for(int i = 0; i &lt; arr.length; i++) is costly as it computes the array length each time. Is this behavior costly in c# for lists and arrays as well. Or at compile-time is it optimized?  Also what about other languages such as Java, how is this handled? Lightning - dynamically creating force:inputField Are wormholes really a valid shortcut to distant points in the universe? Lately I encountered a few times references to wormholes as a way to reach distant places in the universe in a short time. I have to admit I don't have a proper knowledge of the mathematics behind wormholes (although I won't mind a complete GR explanation in the answer, if necessary). All I know is that wormholes are usually compared to something analogous to a tunnel through the planet Earth to reach distant places in less time. The problem is, if I want to reach the other side of the planet I have to travel 20.000 km on its surface and "only" 12.000 km through its center. While the latter is surely shorter, it's still more than 50% of the initial value and this is the best-case scenario. For shorter distances, the difference becomes more and more negligible.  Now, I know enough of GR to understand that this explanation could be a simplification so extreme that any comparison makes little to no sense, but I'm curious to understand if the same problems arise for wormholes too. I don't really care if wormholes exist, are traversable by spaceships and both the crew and the vessel can survive the travel undamaged, I know they are still a theoretical construct and probably there is more than one formulation for it. What I'm really interested in is:   How much shorter will the travel be? I'm interested in Earth proper time, because if the reduction is only in the spaceship proper time, the we can achieve the same result "simply" by traveling closer to the speed of light. Does the amount of reduction in time depend on the distance between the endpoints? If so, it seems unpractical to travel to near stars through wormholes, if the spacetime geometry of our galaxy doesn't help somehow (local curvature should be higher than global curvature). I've recently updated to Ubuntu 20.04. When English is not the chosen language all shortcuts don't work (such as Ctrl + C, Ctrl + A, etc). It was working fine in the previous versions. What happened and What can I do to fix it? How to remove GNOME Shell from Ubuntu 20.04 LTS to install other desktop environment from scratch? What do the words 'RELATED' and 'ESTABLISHED' individually signify in RELATED,ESTABLISHED state in iptables?