Two Matlab icons in Dash
How to remove duplicate entries in dash?
How do I remove all sub-directories from within a directory? This question is kind of a phase II to the first question I posted at   I have a directory that contains a bunch of sub-directories, .zip files, and other random files not contained within a sub-directory.  I'd like a command line script to remove all sub-directories from within the parent directory, but keep all zip files and loose files that don't belong to any sub-directories. All of the sub-directories have content, so I believe I'd need to force their deletion with the -f command.  So basically, a command that looks inside the parent directory (or the current directory), deletes all folders from within it, but keeps all other content and files that are not a folder or contained within a folder.  I understand that deleting items from the command line requires special care, but I have already taken all necessary precautions to back up remotely. Hubble's law says that the universe is expanding. How come the Milky Way and the Andromeda galaxies are on a collision course? How will they end up colliding with each other? I downloaded the iso file for XUbuntu. I created a live usb using Pen Drive Linux. I turned on my computer, booted to the XUbuntu installation screen, and selected "check disk for defects".  A minute later, it says that it found one defect. How do I figure out what this defect is? Exactly half of the elements of $\mathcal{P}(A)$ are odd-sized Let $A$ be a non-empty set and $n$ be the number of elements in $A$, i.e. $n:=|A|$.  I know that the number of elements of the power set of $A$ is $2^n$, i.e.  $|\mathcal{P}(A)|=2^n$.  I came across the fact that exactly half of the elements of $\mathcal{P}(A)$ contain an odd number of elements, and half of them an even number of elements.  Can someone prove this? Or hint at a proof? How To Get Command Blocks Talking in Chat GPU usage monitoring (CUDA) I installed CUDA toolkit on my computer and started BOINC project on GPU. In BOINC I can see that it is running on GPU, but is there a tool that can show me more details about that what is running on GPU - GPU usage and memory usage? I've seen many science popularisation documentaries and read few books (obviously not being scientist myself). I am able to process and understand basic ideas behind most of these. However for general relativity there is this one illustration, which is being used over and over (image from Wikipedia):    I always thought that general relativity gives another way how you can describe gravity. However for this illustration to work, there needs to be another force, pulling the object down (referring to a direction in the attached image). If I put two non-moving objects in the image, what force will pull them together?  So where is my understanding incorrect? Or is general relativity not about explaining gravity and just describes how heavy objects bends spacetime (in that case the analogy is being used not correctly in my opinion)?    UPDATE Thank you for the answers and comments. Namely the XKCD comics is a spot on. I understand that the analogy with bent sheet of fabric pretty bad, but it seems that it can be fixed if you don't bent the fabric, but just distort the drawn grid.   Would you be so kind and answer the second part of the question as well - whether general relativity is explaining gravitational force. To me it seems that it is not (bending of spacetime simply can not affect two non-moving objects). However most of the time it is being presented that it does. I want to know if this is grammatically correct " How long would the conference be for?". Understanding backtick (`) Laplace transform of $1/t$ Best practices for managing and deploying large JavaScript apps What are some standard practices for managing a medium-large JavaScript application? My concerns are both speed for browser download and ease and maintainability of development.  Our JavaScript code is roughly "namespaced" as:  var Client = {    var1: '',    var2: '',     accounts: {       /* 100's of functions and variables */    },     orders: {       /* 100's of functions and variables and subsections */    }     /* etc, etc  for a couple hundred kb */ }   At the moment, we have one (unpacked, unstripped, highly readable) JavaScript file to handle all the business logic on the web application. In addition, there is jQuery and several jQuery extensions. The problem we face is that it takes forever to find anything in the JavaScript code and the browser still has a dozen files to download.  Is it common to have a handful of "source" JavaScript files that gets "compiled" into one final, compressed JavaScript file? Any other handy hints or best practices? Word for an event that will likely never happen again I've read , but none of them are what I am looking for. I once read a book that used a word to describe an event that has happened in the past, but the odds were so astronomical that it will likely never happen a second time. The context I read these words in were the creation of the first life on earth (without any theological ideas). Basically, the text said that the scenario for the creation of the first living organism happened on a planet where conditions were just right by complete chance, and that the odds of this were so astronomical that it would likely never happen again anywhere in the universe over any length of time.  Sample sentence: "The creation of the first organisms was incredibly unlikely, the event can be called a _________ event, or an event that will likely never happen again."   I can't pretend to understand the validity of the claims by the text, but the words they used to describe these events were quite clever (and scientific sounding) that it would make a fun hyperbole.  I thought it was something along the lines of singularity event, but that doesn't sound quite right. p:commandbutton action doesn't work inside p:dialog How can I uninstall a nvidia driver completely ? As expected, Nvidia drivers have reduced my customizations. I can't login to Unity 3D session. I can't find any content to help me to uninstall the driver and I don't know what to do as I have never uninstalled them before. How to Combine IN-Opeator with LookupIds in a caml-query? What's the best way to build a string of delimited items in Java? While working in a Java app, I recently needed to assemble a comma-delimited list of values to pass to another web service without knowing how many elements there would be in advance. The best I could come up with off the top of my head was something like this:  public String appendWithDelimiter( String original, String addition, String delimiter ) {     if ( original.equals( "" ) ) {         return addition;     } else {         return original + delimiter + addition;     } }  String parameterString = ""; if ( condition ) parameterString = appendWithDelimiter( parameterString, "elementName", "," ); if ( anotherCondition ) parameterString = appendWithDelimiter( parameterString, "anotherElementName", "," );   I realize this isn't particularly efficient, since there are strings being created all over the place, but I was going for clarity more than optimization.  In Ruby, I can do something like this instead, which feels much more elegant:  parameterArray = []; parameterArray &lt;&lt; "elementName" if condition; parameterArray &lt;&lt; "anotherElementName" if anotherCondition; parameterString = parameterArray.join(",");   But since Java lacks a join command, I couldn't figure out anything equivalent.  So, what's the best way to do this in Java? Evaluate the integral   $$\int\frac{1}{x^2\left(x^4+1\right)^{3/4}}\,dx$$   My Attempt:  Let $x = \frac{1}{t}$. Then $dx = -\frac{1}{t^2}\,dt$. Then the integral converts to   $$ -\int \frac{t^3}{(1+t^4)^{3/4}}\,dt $$  Now Let $(1+t^4) = u$. Then $t^3\,dt = \frac{1}{4}du$. This changes the integral to  $$ \begin{align} -\frac{1}{4}\int t^{-3/4}\,dt &amp;= -u^{1/4}+\mathcal{C}\\ &amp;= -\left(1+t^4\right)^{1/4}+\mathcal{C} \end{align} $$  So we arrive at the solution  $$\int\frac{1}{x^2\left(x^4+1\right)^{3/4}}\,dx = - \left(\frac{1+x^4}{x^4}\right)^{1/4}+\mathcal{C.}$$  Question: Is there any other method for solving this problem? How does background blur (bokeh) relate to sensor size? This is a somewhat theoretical question.  Suppose I first take a photo of a subject using a full frame sensor DSLR, with a given lens (say 50mm prime lens at f/3.5).  Now suppose I exchange the camera for an APS-C sensor DSLR (with a 1.6× crop factor). I keep the same lens (same focal length, same aperture) and I step back a few meters in order to maintain the field of view (at least keep the same magnification of the subject). I now take a second photo.  Clearly depth of field will have increased between the two photos. But what about background blur (for example, trees at infinity)? Will I have the same amount of background blur, or will that have changed?  I have read somewhere that background blur depends on the physical aperture size. In this case the physical aperture (physical focal length divided by f/stop) stays the same. But should this number be taken in relation to the sensor size? In which case with the smaller APS-C sensor, the physical aperture will be relatively bigger, which would mean more background blur. This would be rather counter-intuitive as we usually consider it to be more difficult to get background blur on an APS-C camera.  Please give the reasoning behind the answer. I would answer the question myself using this  but I can't manage to get it to run on my computer. I want to redirect all requests from example.com to www.example.com.   Preferably, this should happen at DNS level. I tried using PTR records, but that simply fails, returning a 404.  wwww.example.com is an ALIAS for an Elastic Load Balancer.  What’s the simplest way to achieve this? Question of remainder on dividing by 7 Question :  What is the remainder when   $$ 10^{10} + 10^{10^2} +10^{10^3} + \ldots + 10^{10^{100}} $$  is divided by $7$?