Screencast only records a black box
Why are some of my screen-recording/capturing/sharing applications (or app features) not working in Ubuntu 17.10 (and later releases)?
Where did the age go on the network profile? Ever since the profile redo, the age was shown in the network profile, but not in the per-site profiles. So if someone wanted to see the age, they had to go to the network profile. However.. It's vanished! The field is still there in the profile editing, however. It doesn't appear as if this was implemented:   So... Where is it? Continuous Fibonacci number F(n) About the structure of ''There are/is'' I want to discuss the structure of ''There are/is''. First of all, what is the difference between:  There are three children.  and  Three children exist.  Do they have the same meaning? And secondly, In my native language, we would say that  Üç çocuk vardır.  &quot;Üç çocuk&quot; = Three children, &quot;var&quot; = existence (something  that exists, a being), and &quot;dır&quot; is a copula. So basically, this structure is not different from -for example- ''three children is a car''. ''a car'' and ''existence'' have the same function. But ın English, that structure that I have mentioned is confusing for me. I know that you are all used to it. Some can say ''What's the problem with that? It is just ''there are'' and ''there is.'' ''. I realize that I still did not ask a question. Well, let me try to ask a good one, I guess. Normally, ''there'' means a place where I am not in that place. Is there any relevance between ''there'' that means a place where I am not in that place AND ''There'' that is used in the structure of ''There are/is''? What kind of structure is this? By the way, I am new in English. Please excuse my naive usage of language. What do you think about it? Proving by induction that $\sum\limits_{k=2}^n \frac1{k^2}\le 1$ Web service - current time zone for a city? Is there a web service of some sort (or any other way) to pull a current time zone settings for a (US) city. For the parts of the country that don't follow the Daylight Saving Time and basically jump timezones when everyone else is switching summer/winter time... I don't fancy creating own database of the places that don't follow DST. Is there a way to pull this data on demand?   I need this for the database server (not for client workstations) - there entities stored in the database that have City, State as properties. I need know current timezone for these entities at any moment of time. Convergence/Divergence of infinite series $\sum_{n=1}^{\infty} \frac{(\sin n+2)^n}{n3^n}$ $$ \sum_{n=1}^{\infty} \frac{(\sin n+2)^n}{n3^n}$$  Does it converge or diverge?   Can we have a rigorous proof that is not probabilistic?   For reference, this question is supposedly a mix of real analysis and calculus. What are the C++ coding and file organization guidelines you suggest for people who have to deal with lots of interdependent classes spread over several source and header files?  I have this situation in my project and solving class definition related errors crossing over several header files has become quite a headache. If $-1&lt;x&lt;1$ show that $\lim\limits_{n \to \infty}{n\,x^n} = 0$. I don't have idea. I only prove that $n\,x^n$ is decreasing. Does one work in or on an aeroplane? In an exam paper, there was a picture of an air stewardess in the aeroplane serving passengers. One of my pupils wrote the following:      The air stewardess works on an aeroplane.    Shouldn't it be the air stewardess works in an aeroplane? How can I find all files that do NOT contain a text string? What concise command can I use to find all files that do NOT contain a text string?  I tried this (using -v to invert grep's parameters) with no luck:  find . -exec grep -v -l shared.php {} \;   Someone said this would work:  find . ! -exec grep -l shared.php {} \;   But it does not seem to work for me.   has this example:  find ./logs -size +1c  &gt; t._tmp while read filename do      grep -q "Process Complete" $filename      if [ $? -ne 0 ] ; then              echo $filename      fi done &lt; t._tmp rm -f t_tmp   But that's cumbersome and not at all concise.  ps: I know that grep -L * will do this, but how can I use the find command in combination with grep to excluded files is what I really want to know.  pss: Also I'm not sure how to have grep include subdirectories with the grep -L * syntax, but I still want to know how to use it with find :) Zoom in/out on click in OpenLayers 3? Confused By Copyright Rules \xymatrix undefined How to configure an exposed filter in a view using a date picker? I would like to update VirtualBox on my 32 bit Ubuntu 15.04 machine from 4.3.26 to 4.3.28, using a Debian package I manually downloaded from . But simply double-clicking the package opens up the Software Centre which gives an error that installing it would break an existing package (the exact message was:   Breaks existing package 'virtualbox' conflict: virtualbox-4.3 ()   and it does not appear to have an option to ignore this and proceed with the installation anyway. Is there a command-line work-around this problem, perhaps? Is $\frac{\textrm{d}y}{\textrm{d}x}$ not a ratio? In the book Thomas's Calculus (11th edition) it is mentioned (Section 3.8 pg 225) that the derivative $dy/dx$ is not a ratio. Couldn't it be interpreted as a ratio, because according to the formula $dy = f'(x)dx$ we are able to plug in values for $dx$ and calculate a $dy$ (differential). Then if we rearrange we get $dy/dx$ which could be seen as a ratio.   I wonder if the author says this because $dx$ is an independent variable, and $dy$ is a dependent variable, for $dy/dx$ to be a ratio both variables need to be independent.. maybe? Getting "Not found" message when running a 32-bit binary on a 64-bit system I recently installed Ubuntu Server edition 13.10 (Saucy Salamander). But I have run into a bit of problem. At the end of the installation, it asks about several extra packages whether you want them or not, like OpenSSH server and virtual machine host. Here's what I'm looking at:  Now, my problem is that I can't remember if I have checked the &quot;virtual machine host&quot; checkbox. How do I check if my server has the corresponding packages? What packages come with the virtual machine host? Getting MTP enabled devices to work with Ubuntu? Since Ubuntu 13.04 storage access to external devices via MTP is supposed to work out of the box via a GVFS-MTP module.      While this question is about the Galaxy Nexus, other Android devices as well as Windows Phones and MTP enabled media players are also supported.      For troubleshooting see .     I am having quite a bit of problems getting file-transfers working over MTP with the Galaxy Nexus. I am using Kubuntu 11.10 64-bit, and this is what I have done and the results I get:   Added rule for device in /etc/udev/rules.d/51-android.rules. The rule is the following and works for adb:  SUBSYSTEMS=="usb", ATTRS{idVendor}=="04e8", ATTRS{idProduct}=="6860", MODE="0666", OWNER="leob" #Galaxy Nexus  Restarted udev (and computer just to make sure).   Adb works, and all methods for reading from the device via MTP seems to work (I have tried mounting with mtpfs, gmtp and using the mtp-tools package directly). When I try to write to the device however, nothing I have tried works.  As an example, running mtp-newfolder test_dir 0 0 gives the following output:  libmtp version: 1.1.0 Device 0 (VID=04e8 and PID=6860) is a Samsung GT-P7510/Galaxy Tab 10.1. Folder creation failed. ERROR: Could not close session!   If I run mtp-folders after a failed mtp-newfolder without re-plugging the device, I get the following output:  Attempting to connect device(s) Device 0 (VID=04e8 and PID=6860) is a Samsung GT-P7510/Galaxy Tab 10.1. PTP_ERROR_IO: failed to open session, trying again after resetting USB interface LIBMTP libusb: Attempt to reset device mtp-folders: Successfully connected Friendly name: (NULL) Error 1: Get Storage information failed. Error 2: PTP Layer error 02fe: get_all_metadata_fast(): could not get proplist of all    objects. Error 2: (Look this up in ptp.h for an explanation.) Error 2: PTP Layer error 02fe: get_handles_recursively(): could not get object handles. Error 2: (Look this up in ptp.h for an explanation.) LIBMTP_Get_Storage() : Resource temporarily unavailable OK.   Accompanied by the following in dmesg:  [ 1000.912082] usb 2-4: reset high speed USB device number 7 using ehci_hcd [ 1001.045877] usb 2-4: usbfs: process 3166 (mtp-folders) did not claim interface 0 before use   Does anyone have any idea about what to do?  EDIT:  I also tried the PTP mode. Again, reading works fine, but I cannot write anything to the device. Numerical integration of divergent function I am having trouble with the numerical integration of a divergent function. For example, \begin{equation} n= \int f(x)\,dx = \displaystyle\int \dfrac{\Theta(x-\varepsilon)\,dx}{\sqrt{x-\varepsilon}} \end{equation} is not behaving good when calculated numerically: \begin{equation} n_\text{numerical} \approx f(x_j)(x_j-\varepsilon) + \sum_{k=j+1}^N f(x_k)\Delta x \end{equation} with \begin{equation} x_i = x_\text{min} + i\Delta x \end{equation} and $x_j$ being the smallest point larger than $\varepsilon$. Due to the divergent behavior of $f(x)$ near $\varepsilon$, the numerical result has discontinuities and jumps at every $\varepsilon=x_i$ when I sweep $\varepsilon$. The smoothness of this integration is crucial in the convergence of my simulations. Can anybody suggest a simple trick to solve the problem? All I need is to have a continuous numerical result by continuously changing $\varepsilon$.