I have an Intel NUC running 3.13.11.6; and I have written an application that runs some simple data polling (cpu, memory usage, disk usage etc ...).  The NUC is headless, so I connect via SSH (putty) and can execute the program.  My issue is that I need the program to run for days; and if I close the putty session, the process is killed.  I do not have cron on the system, or some way to remote execute the application (that I am aware of).  *** edit - some recommendations for using screen and tmux were great, however I am learning this is a custom implementation of Ubuntu and these are not available.  Does anyone have any suggestions on the best way to run an application on a headless Ubuntu system and not have the process killed when the ssh session disconnects?  Appreciate any help!  Thank you,  Dan.
Let's say I launch a bunch of processes from a ssh session. Is it possible to terminate the ssh session while keeping those processes running on the remote machine?
Is there a way to export large multi-layered Illustrator file to Photoshop?  When I export with preserve layers and text edit-ability, the complex layers are flattened. I've reorganized my layers to have simple groupings but that's time consuming.  Is there a more effective way of doing this? Or script to automate it? Taylor expansion for $\arcsin^2{x}$ I stumbled upon this particular expansion that was included in  post.    $$ \displaystyle \arcsin^{2}(x) = \frac{1}{2} \sum_{n=1}^{\infty} \frac{1}{n^{2} \binom{2n}{n}} (2x)^{2n}$$    This caught my eye because I remember trying to derive a Taylor series for $\arcsin^{2}(x)$ a while ago without much success.  Can anyone prove this or point me to a material that would show a proof of this identity?  EDIT :  Feel free to use any mathematical apparatus at hand. I'm not interested in a proof fit for a certain level, nor am I looking for utmost elegance (though that would be lovely). When I input [asdf][lisp] into the search field on , without being logged in, only one tag remains. Is it broken? How to download packages from a command-line given repository? It is not about the common download &amp; install thing, what apt (aptitude, etc) does, it is a scripted download a package file.  I found the dget tool for this task, which works quite well. But, unfortunately, it doesn't have any option to specify a different repository URL as it is given in the /etc/apt/sources.list.  Is it somehow possible? Actually, a dget-like functionality would be the best, but where I can also specify the repo URL.    P.s. thank you very much the scripts, but I would like to prefer a debian tool for this very simple task. It will be part of a buildscript, for external usage, and any unneeded complexity has intolerable collateral costs. It must be done by a debian tool.  P.s.2. Finally I solved this with updating the system-wide repos, and downloading the packages with dget. Thank you very much the scripts! Is it ok to say 'sorry' where you otherwise would use 'excuse me'?  Example: "Sorry, but could you show me the way to the next train station?" Is it possible to convert a Physical Ubuntu Install (Intel based PC with Ubuntu 10.10) to a virtual box disk, so that I can use that same environment on a separate pc or can keep it virtual for testing?  Something similar to "Disk2VHD" which converts a physical Windows 2K3 and above box into a VHD or VMware image.  Will be grateful for your assistance ! Kind Regards Mathematica envelope for the bottom of a plot, a generic function How to modify an invalid '/etc/sudoers' file? Speed $v$ of a wave on a tightrope I generally know how to use a hyphen, but when should I use an en-dash (–) instead of an em-dash, or when should I use a hyphen (-) instead of an em-dash (—)? The below statement is a true/false exercise.  Statement: For all square matrices A and B of the same size, it is true that $(A + B)2 = A^2 + 2AB + B^2$.  My thought process: Since it is not a proof, I figure I can show by example and come to a valid conclusion based on such example.  My work:  Come up with a square matrix A and B let both be a 2 by 2 matrix(rows and cols must be same).  Matrix $A$:  $A = \begin{array}{ccc} 3 &amp; 5 \\ 4 &amp; 6 \\ \end{array} $  Matrix $B$:  $B =  \begin{array}{ccc} 5 &amp; 8 \\ 9 &amp; 4 \\ \end{array} $  $A + B =  \begin{array}{ccc} 8 &amp; 13 \\ 13 &amp; 10 \\ \end{array}$  $(A + B)^2 =  \begin{array}{ccc} 233 &amp; 234 \\ 234 &amp; 264 \\ \end{array}$  $A^2 =  \begin{array}{ccc} 29 &amp; 45 \\ 36 &amp; 56 \\ \end{array}$  $(AB) =  \begin{array}{ccc} 60 &amp; 44 \\ 74 &amp; 56 \\ \end{array}$  $2(AB) =  \begin{array}{ccc} 120 &amp; 88 \\ 234 &amp; 112 \\ \end{array}$  $B^2 =  \begin{array}{ccc} 97 &amp; 72 \\ 81 &amp; 88 \\ \end{array}$  $A^2 + 2AB + B^2 =  \begin{array}{ccc} 246 &amp; 205 \\ 265 &amp; 256 \\ \end{array}$  Based my above work, the answer is false.   Is there another way to approach the problem? It seems like a lot of work needed to be done for a true/false question which raised my suspicion about whether there is a better way to look at the problem. This is a canonical question and answer developed by the community to help address common questions. If you've been directed here, or your question has been closed as a duplicate, please look through the resources here and use them to shape more specific questions. To browse all canonical questions and answers, including more unit test resources, navigate to the  tag.  This canonical question is intended to address several classes of common questions by providing a quick summary and links to comprehensive resources:   How do I start writing my first unit test?  How do I unit test this code?  I need help writing this unit test.   Salesforce Stack Exchange looks for detailed, specific questions that the community can help you with, and can't write tests on your behalf. We feel that working with the resources below can help you get started, and we encourage you to make an attempt to write your test and return to SFSE with your specific questions when you encounter challenges you can't resolve. I tried to install wine using these commands: sudo apt-get install -y wine  And: sudo apt-get install wine  But terminal says that: Reading package lists... Done Building dependency tree        Reading state information... Done Package wine is a virtual package provided by:   winehq-staging 2.16.0~zesty   winehq-stable 2.0.2~zesty   winehq-devel 2.16.0~zesty   wine-development 2.0-3ubuntu1 You should explicitly select one to install.  E: Package 'wine' has no installation candidate  So there are 4 different version of wine. What is the difference between these versions. Which one is better? I wanted to install Internet Explorer from it and I installed winehq-stable. But I couldn't see that among applications in Winetricks. Do the other versions of wine have more applications to install? What is the difference? I was trying to concatenate text files in sub-folders and tried:  cat ./{mainfolder1,mainfolder2,mainfolder3}/{subfolder1}/book.txt &gt; out$var   However this did not return anything. So, tried adding a non existing 'subfolder2'  cat ./{mainfolder1,mainfolder2,mainfolder3}/{subfolder1,subfolder2}/book.txt &gt; out$var   And this time it did work out, concatenating the files successfully. Why does this happens? Evaluation of Indefinite Integral resulting in Hypergeometric Function I am attempting to derive the result:  $$ \int \left(1+x^n\right)^{-1/m}dx= x\,_2F_1\left(\frac 1m,\frac 1n;1+\frac 1n;-x^n\right)$$  First, I start off with the binomial expansion of the integrand to get:  $$\int\sum_{k=0}^{\infty}\frac{(1/m)_k}{k!}\left(-x^n\right)^kdx  $$  Then, I pull out a $-1$ and interchange summation and integration:  $$\sum_k\int (-1)^k\frac{(1/m)_k}{k!}x^{nk}dx  $$  $$ \sum_k (-1)^k\frac{(1/m)_k}{k!}\frac{x^{nk+1}}{nk+1} $$  $$ x\sum_k \frac{(1/m)_k}{k!}\frac{(-x^n)^k}{nk+1}  $$  So, I'm just right there, but not sure how to express this series in the general form of a hypergeometric series with the two additional Pochhammer symbols.  I even typed this last series into Mathematica, and it returned the Hyper. Function. What am I missing, or how do I transform this last series into the desired form? I've heard that i can travel to the US any time before my tourist visa expiry.  Is that true?  (please advise) Im trying to solve the following question         In the second step  where do they get $k!=2^k-1?$ I was wondering whether the time shown is the time I would be arriving in France so its time zone etc.  I know France is an hour ahead so not sure if I'm right in my assumption... It would be useful to know as I plan on traveling to the States and other European countries soon as well. I'm calculating the covariance of a distribution in parallel and I need to combine the distributed results into on singular Gaussian. How do I combine the two?  Linearly interpolating between the two almost works, if they are similarly distributed and sized.   provides a forumla at the bottom for combination but it doesn't seem right; two identically distributed distributions should have the same covariance, but the formula at the bottom of the page doubles the covariance.  Is there a way to combine two matrices? Probability that median falls within a range? If I draw 5 samples from a distribution that is cont., what is the probability that the median of the population is between the xmin and xmax of the draw samples?  What is the formula to apply here?