I am looking for a small application that allows to capture a screen section and directly render to a gif file.  Is there any application that does this?  I searched a lot, but I didn't find one compatible with Linux/Ubuntu...
I've seen animated GIF images of screen casts (like the one below) promoted a few times on this site as a way to improve answers.    What toolchain is being used to create these? Is there a program that does this automagically, or are people taking screencasts, converting them into a series of static frames, and then creating the GIF images?
degree of freedom of a rigid body 5 or 6? I'm confused here. I have a three particle (rigid) system. What would be the degree of freedom? I found out five. 3 coordinates for center of mass and 2 for describing orientation. But we have only three constraints, i.e. three equations that reduce 9 coordinates by 3, 9 - 3 = 6, which gives 6 degrees of freedom?? Did I miss something above? Can a magnetic field be induced without an electric field? Because, as far as I know, a time varying electric field induces a magnetic field an vice versa.  But in the case of conductors carrying currennt, it doesn't seem that electric field varies with time, then how is a magnetic field induced? Find the first occurrence/starting index of the sub-array in C# Exit of "> " mode in Unix shell In sh (not Bash), how would we abort execution of command when the prompt is in &gt; mode?  For example, when entering a string with quotes only at the beginning, it makes the prompt look like &gt;, without the ability to quit it normally, unless hitting Ctrl + D. Example:  root@MyPC:~# echo "hello &gt; I am &gt; (How do I exit of this mode?)   In case that I don't know which character delimits the string (" or ' or simply escaping a newline/spaces with backslash), is there a way to let Bash know that I want to abort the execution of the current command? How many irreducible monic quadratic polynomials are there in $\mathbb{F}_p[X]$? Can some of you help me with my homework?     I had to count the irreducible, quadratic, monic polynomials in $\mathbb{F}_p[X]$ for arbitrary $p$.    I will show you what I tried myself.  Research effort  First of all the set $\{X^ 2 + bX +c : b, c \in \mathbb{F}_p \}$ contains $p^2$ elemenst. We need to substract the amount of elements that is reducible. These elements are exactly the set $A = \{(X+c)(X+d) : c, d \in \mathbb{F}_p \}$. There are $p(p-1)$ pairs of $(a,b) \in \mathbb{F}_p \times \mathbb{F}_p$ such that $a \neq b$, and there are $p$ pairs such that $a=b$.     When $a$ and $b$ are unequal, whe know that $a$ and $b$ can be swapped without changing anything to the polynomial $(X+a)(X+b)$, so I obtained that $|A| \leq p +(p-1)- \frac{1}{2}(p-1)=p-\frac{1}{2}(p-1)$.  In other to find out these are the elements, or that there are still less, I thought I had to assume that $(X+c)(X+d) = (X+\gamma)(X+\delta)$, to deduce some information about the realation between $(c,d)$ and $(\gamma, \delta)$, but this led to taking square roots in $\mathbb{F}_p$, and I am not familiar with that.  Could you please provide me some more information? Is the function $f(x)=|x|^{1/2}$ Lipschitz continuous near $0$? If yes, find a constant for some interval containing $0$.   I think the answer is yes since I can find $L=1$ that satisfies Lipschitz continuity criteria in a interval close to $0$, am I right? Why can't I edit attribute table imported through 'text as layer' I imported the coordinates from an Excel table. They show as single points as intended. Now I want to add columns to the attribute table, but I'm not able to edit it. I wanted to import the following columns from Excel as well, but that doesn't seem to work either.  Sorry for the noob-question, but I couldn't find anything relating the theme through google and such.  Ok, with pictures then: I want to use that to add columns with information to these       You see, the small pensil thingy is greyed out, so I can't edit anything in this layer and I can't add any information to my points.  If I try Ale suggestion I get this error: Comparing areas in scanned historical land use maps using QGIS? Can I publish an article or thesis about my research without supervisor? 14.04 --> 16.04 failed; apt (>= 1.0.1ubuntu2.13)' is not installed How to turn off Facebook notifications on Mac OS X? How to turn off Facebook notifications on Mac OS X Mountain Lion? In Windows, you can run android application using BlueStack.   I was wondering, is there any way these apps can be run on Ubuntu 12.04? java.net.SocketException: Connection reset I am getting the following error trying to read from a socket. I'm doing a readInt() on that InputStream, and I am getting this error. Perusing the documentation this suggests that the client part of the connection closed the connection. In this scenario, I am the server.  I have access to the client log files and it is not closing the connection, and in fact its log files suggest I am closing the connection. So does anybody have an idea why this is happening? What else to check for? Does this arise when there are local resources that are perhaps reaching thresholds?    I do note that I have the following line:  socket.setSoTimeout(10000);   just prior to the readInt(). There is a reason for this (long story), but just curious, are there circumstances under which this might lead to the indicated error? I have the server running in my IDE, and I happened to leave my IDE stuck on a breakpoint, and I then noticed the exact same errors begin appearing in my own logs in my IDE.  Anyway, just mentioning it, hopefully not a red herring. :-( Equivalence Relation problem Let $S$ be the relation on $\mathbb{N} \times \mathbb{N}$ defined by $(a,b)S(c,d)$ if and only if $ad=bc$. Prove this is an equivalence relation on $\mathbb{N} \times \mathbb{N}$.  I think I've found this to be reflexive and symmetric, but I'm stuck on transitivity. Can someone check my work so far and assist with testing transitivity?  Reflexive: Let $(x,y)S(x,y)$. Then $xy = yx$. So $S$ is reflexive. Symmetric: Suppose $(a,b)S(c,d)$. Then, $ad = bc$. Therefore, $da = cb$ and $cb = da$. Therefore, $(c,d)S(a,b)$. Thus, $S$ is symmetric.  Transitive: Suppose $(a,b)S(b,c)$. Then $ac = bb$.   This is where I'm stuck. Any ideas? Using `M` instead of `k` when rep is >= 1M on https://chat.stackexchange.com/users I read on  ()    Shouldn't it be 1.03m or (if we really follow the conventions of the metric system) 1.03M instead? How to create an extruded halftone effect in illustrator or photoshop Under , is $\exists x(x=a)$ true in every interpretation in first order logic (FOL) with equality? If so, could $\exists x(x=a)$ be considered a tautology? This question was motivated by  which was closed for lacking clarity. Here I have attempted to add that clarity myself so that the same question can be useful to others who are wondering a similar thing. This is a self answer question. Please help me to stop auto login in Skype. There is an account that is always login again and again, although I chose to logout and sign in with another Skype name. I tried on Settings/applications/Skype to kill the account and to quit synchronise, but still whenever I open Skype again, I'm logging in automatically. How to force the Y axis to only use integers in Matplotlib? I have created a logo with pen tool in Illustrator but between lines (where they intersect with each other) there is a gap where it gets the color of the background.  Something like this:  (Black color is the background color) - As you can see where the paths join each other there is a kinda dotted black line. I Grouped them but still the same. I converted to jpeg just to be sure it is not only shown like that but same effect.   NOTE: I want to export that logo as SVG file type and use it in the WEB. I tried some solutions given like anti-aliasing in preferences or art optimize when saving for optimization. But still I have same problem. I want to get that logo in SVG and put it on the web where it will display clean without those strange gaps.  How can i get rid of this?