Let's say I run a command which takes a long time to do its stuff, but I don't want or need to look at it the whole time, and as I need to do some other stuff as well I might get into that and forget to check on how the command is doing for some time... Then when I finally do check I may find that the command finished 3 hours ago and needed my attention then... Or perhaps it didn't need my attention, if I had seen that it had finished at the time I would have had more time to run more commands...  So I was wondering if there is a way to get it so that when a command or program has been run, whenever it finishes and returns to $, for it to make a little sound, like play an mp3 file or something? Though it would be acceptable just to get this working in gnome-terminal, I would like it in as many CLI environments as possible including the TTYs if that would be possible... I am running Ubuntu GNOME 15.10 with GNOME 3.18.
I have started a long process through a terminal. Is it possible to make the Ubuntu terminal make a sound once the process is complete? This way, I don’t need to keep checking, but will instead be notified through a sound.
I updated LyX to 2.3.0-1, and found that LyX was displaying all the "-" characters in Math Mode as "\lyxminus". No such problem occurs when entering outside of Math Mode. LyX also seems to have no problem compiling to TeX, and the PDF output looks normal.  I removed and re-installed LyX, and this issue was still there.   Does anyone have any ideas on what might be going on? I am using Linux Mint 18.2 Sonya.  Note: I previously saw this question ask about the same thing, but the author appears to have deleted their post: If $$(1+ \cos A) (1+ \cos B) (1+\cos C)= y = (1- \cos A) (1-\cos B) (1-\cos C)$$ then prove that $$y = \pm \sin A \sin B \sin C$$ Let $A \in \mathbb{R}^{p \times p}$ and $B \in \mathbb{R}^{q \times q}$ be nonsymmetric positive definite matrices in the sense that $v^T A v &gt; 0, \forall v \in \mathbb{R}^p$ and $v^T B v &gt; 0, \forall v \in \mathbb{R}^q$.  I know that $A \oplus B$, i.e. a matrix with a block structure \begin{align} \pmatrix{A &amp; 0 \\          0 &amp; B} \end{align} is positive definite and I also know that if $p=q$, then $A+B$ is positive definite as well.  Can I say that as well if the blocks overlap partially? When?   For instance a matrix as follows: \begin{align} \pmatrix{a_{11} &amp; a_{12} &amp; a_{13} &amp; a_{14} &amp; 0&amp; 0\\          a_{21} &amp; a_{22} &amp; a_{23} &amp; a_{24}&amp; 0&amp; 0\\          a_{31} &amp; a_{32} &amp; a_{33} + b_{11} &amp; a_{34} + b_{12} &amp;b_{13}&amp;b_{14}\\          a_{41} &amp; a_{42} &amp; a_{43} + b_{21} &amp; a_{44} + b_{22} &amp;b_{23}&amp;b_{24}\\          0 &amp; 0 &amp; b_{31} &amp; b_{32} &amp;b_{33}&amp;b_{34} \\          0 &amp; 0 &amp; b_{41} &amp; b_{42} &amp;b_{43}&amp;b_{44}} \end{align} Is floating point math broken? Why isn't Force Speed used more often? How do I convert materials from Blender Internal to Cycles? I know this may be a tough or confusing question, but I have numerous existing materials I created and reuse for a project, which were all prepared for Blender Internal.  Now, I want to start the transition to Cycles, but I've hit a roadblock. How can I transition my materials without completely starting over? Or should I just forget it and start with fresh materials? Notice: Undefined variable: logged in C:\xampp\htdocs\Site\Site\view_category.php How can I highlight text before a character with listing? Are any fictional worlds available in some GIS format? Is there any fictional world (e.g. ,  etc.) which could be used in a GIS context?  For example, an MBTiles archive and a shapefile or any other format usable with OpenLayers / Polymaps / Leaflet? Getting hybrid graphics to work nvidia-prime GT650M I recently made the switch to Ubuntu. Everything on my laptop works fine except my hybrid graphics card. It is Intel graphics combined with Nvidia GeForce GT650M. I tried Bumblebee, but primusrun doesn't work (segmentation fault, core dumped) and optirun works with glxspheres64, but steam games look worse with optirun than with Intel graphics (e.g. Surgeon Simulator 2013 runs fine with Intel and hangs a lot with optirun)   I tried Nvidia Prime, but it gives me a black screen on startup after install, so I can't do anything and have to power off my PC with the power button. I also tried nvidia-prime 0.5 on Ubuntu 14.04, and then I get 'low-graphics mode' and I can't get to Unity. The Stack Exchange beta iOS app distributed over TestFlight will expire in 2 days has expired. After the 100 day test period, the app won't start any more so all beta testers can't use the app then.  Can we please get an updated release so we don't have to remove the app and install the current release from the App Store instead? Why use the 'ref' keyword when passing an object? Correct way of declaring pointer variables in C/C++ In classical logic, why is $(p\Rightarrow q)$ True if $p$ is False and $q$ is True? How to dynamically change a web page's title? I have a webpage that implements a set of tabs each showing different content. The tab clicks do not refresh the page but hide/unhide contents at the client side.  Now there is a requirement to change the page title according to the tab selected on the page ( for SEO reasons ). Is this possible? Can someone suggest a solution to dynamically alter the page title via javascript without reloading the page? Prove that $1^2+2^2+\cdots+n^2=\frac{n(n+1)(2n+1)}{6}$ for $n \in \mathbb{N}$. Problem: Prove that $1^2+2^2+\cdots+n^2=\frac{n(n+1)(2n+1)}{6}$ for $n \in \mathbb{N}$.  My work: So I think I have to do a proof by induction and I just wanted some help editing my proof.  My attempt:  Let $P(n)=1^2+2^2+\cdots+n^2=\frac{n(n+1)(2n+1)}{6}$ for $n \in \mathbb{N}$.  Then $$P(1)=1^2=\frac{1(1+1)(2+1)}{6}$$ $$1=\frac{6}{6}.$$ So $P(1)$ is true.  Next suppose that $P(k)=1^2+2^2+\cdots+k^2=\frac{k(k+1)(2k+1)}{6}$ for $k \in \mathbb{N}$. Then adding $(k+1)^2$ to both sides of $P(k)$ we obtain the following: $$1^2+2^2+\cdots+k^2+(k+1)^2=\frac{k(k+1)(2k+1)}{6}+(k+1)^2$$ $$=\frac{2k^3+3k^2+k+6(k^2+2k+1)}{6}$$ $$=\frac{2k^3+9k^2+13k+6}{6}$$ $$=\frac{(k^2+3k+2)(2k+3)}{6}$$ $$=\frac{(k+1)(k+2)(2k+3)}{6}$$ $$=\frac{(k+1)((k+1)+1)(2(k+1)+1)}{6}$$ $$=P(k+1).$$ Thus $P(k)$ is true for $k \in \mathbb{N}$. Hence by mathematical induction, $1^2+2^2+\cdots+n^2=\frac{n(n+1)(2n+1)}{6}$ is true for $n \in \mathbb{N}$. Understanding shape and calculation of confidence bands in linear regression I am trying to understand the origin of the curved shaped of confidence bands associated with an OLS linear regression and how it relates to the confidence intervals of the regression parameters (slope and intercept), for example (using R):  require(visreg) fit &lt;- lm(Ozone ~ Solar.R,data=airquality) visreg(fit)     It appears that the band is related to the limits of the lines calculated with the 2.5% intercept, and the 97.5% slope, as well as with the 97.5% intercept, and the 2.5% slope (although not quite):  xnew &lt;- seq(0,400) int &lt;- confint(fit) lines(xnew, (int[1,2]+int[2,1]*xnew)) lines(xnew, (int[1,1]+int[2,2]*xnew))     What I don't understand are two things:   What about the combination of 2.5% slope &amp; 2.5% intercept as well as 97.5% slope and 97.5% intercept? These give lines that are clearly outside the band plotted above. Maybe I don't understand the meaning of a confidence interval, but if in 95%  of the cases my estimates are within the confidence interval, these seem like a possible outcome? What determines the minimum distance between the upper and lower limit (i.e. close to the point where the two lines added above intercept)?    I guess both questions arise because I don't know/understand how these bands are actually calculated.   How can I calculate the upper and lower limits using the confidence intervals of the regression parameters (without relying on predict() or a similar function, i.e. by hand)? I tried to decipher the predict.lm function in R, but the coding is beyond me. I'd appreciate any pointers towards relevant literature or explanations suitable for stats beginners.  Thanks. I want wp_link_pages (mutli-page posts) to display the page numbers, the word "previous" before those numbers, and a "next" after those numbers.  It would look like this:  Prev 1, 2, 3, 4 Next  I'm attempting to do this without a plugin.  Here's what I've tried so far, but it isn't working, it is only displaying numbers.  &lt;?php wp_link_pages(array(     'before' =&gt; '&lt;span style="clear:both; display:block"&gt;Pages',      'after'  =&gt; '&lt;/span&gt;',     'next_or_number'=&gt;'number',     'previouspagelink' =&gt; 'previous',     'nextpagelink'=&gt; 'Next' )); ?&gt; What’s the best way to reload / refresh an iframe? I would like to reload an &lt;iframe&gt; using JavaScript. The best way I found until now was set the iframe’s src attribute to itself, but this isn’t very clean. Any ideas? Counting inversions in an array I'm designing an algorithm to do the following: Given array A[1... n], for every i &lt; j, find all inversion pairs such that A[i] &gt; A[j]. I'm using merge sort and copying array A to array B and then comparing the two arrays, but I'm having a difficult time seeing how I can use this to find the number of inversions. Any hints or help would be greatly appreciated.