I know many similar approaches have been asked about this error but none of the solutions solved my problem. I was trying to install Nord VPN on my Ubuntu by this command: sudo apt-get install {/path/to/}nordvpn-release_1.0.0_all.deb  and it gives me this erorr: E: Unable to locate package {/path/to  What shold I do?
Say, I have foo-1.2.3.deb which depends on perl and python, however, running command:  dpkg -i ./foo-1.2.3.deb   won't install these dependencies. So I must apt-get install perl python by hand.  How to make dpkg -i install these dependencies for me automatically?
Newton's Law of Graviation: Why $G$ and not e.g. $\dfrac{1}{4\pi G_0}$? Every subsequence of $x_n$ has a further subsequence which converges to $x$. Then the sequence $x_n$ converges to $x$. Is the following true? Let $x_n$ be a sequence with the following property: Every subsequence of $x_n$ has a further subsequence which converges to $x$. Then the sequence $x_n$ converges to $x$.  I guess that it is true but I am not sure how to prove this. A sum of series problem: $\frac{3}{1!+2!+3!} + \frac{4}{2!+3!+4!} + \cdots + \frac{2008}{2006!+2007!+2008!}$ I have a question regarding the sum of this series: $$\frac{3}{1!+2!+3!} + \frac{4}{2!+3!+4!} + \cdots + \frac{2008}{2006!+2007!+2008!}$$ My approach: I found that this sum is equal to: $$\sum_{n=3}^{2008}\frac{n}{(n-2)!+(n-1)!+(n)!}$$  I reduced it to : $$\sum_{n=3}^{2008}\frac{1}{n(n-2)!}$$  Please suggest how to proceed further. Why not use development provisioning instead of ad hoc? How do I run an executable file with a double click? I'm trying to run an executable (testdisk) but double click doesn't work. The only way is to run:  sudo ./testdisk   from terminal. But I'd like to open executables with double click in future. How can I do this? We are always introduced to magnets by pictures illustrating a parallepiped magnet, a horseshoe magnet, etc... Anyway the first time we actually calculate a magnetic field is for eelectromagnets. Indeed I've rarely seen explaining or calculating the magnetic field of a permanent magnet. I know formulas for the magnetic field of a moving charge, around a conductive wire, inside a solenoid, but I don't have idea on how to go about calcualting the filed of a simple permanent magnet. It's like that without the help of electricity I'm stuck. I'd guess it would be heavily dependent on the magnetic material, its shape and the medium in which is placed. I hope that someone would provide me some insights on why such formulas are  never introduced in most physics courses and lay down some examples of a permanent magnet field caluclation. How to prevent book class from vertically justifying the contents? If we use the book class, the output looks like the following screenshot.    But if we use the article class, the output looks better as follows.    The MWE is given as follows. Note: please enable -shell-escape!  \documentclass[12pt]{article}% please change to article and compare the output.  \usepackage{filecontents} \begin{filecontents*}{"article sample.tex"} \documentclass{article} \usepackage{lipsum} \begin{document} \lipsum[1-20] \end{document} \end{filecontents*}  \usepackage{showexpl}  \lstset {     breaklines=true,     breakindent=0pt,     tabsize=2,     columns=flexible,     language={[LaTeX]TeX},     basicstyle=\small\ttfamily\hbox{}, }  \newcount\x  \newcommand\MyLTXinputExample[2][2mm]{% % #1: length of gap, % #2: filename with .tex,      \lstinputlisting[caption=\url{#2.tex}]{"#2.tex"}     \bgroup         \parskip=#1\relax         \fboxsep=0pt         \pdfximage{#2.pdf}%         \x=0         \loop             \ifnum\x&lt;\pdflastximagepages                 \advance\x by 1                 \noindent\hfill                 \fbox{\includegraphics[width=0.5\dimexpr\linewidth-4\fboxrule-#1\relax,page=\x]{"#2"}}%                                  \ifnum\x&lt;\pdflastximagepages                 \advance\x by 1                 \hfill                 \fbox{\includegraphics[width=0.5\dimexpr\linewidth-4\fboxrule-#1\relax,page=\x]{"#2"}}%             \fi                 \hfill\null\par         \repeat     \egroup }  \PassOptionsToPackage{obeyspaces}{url} \usepackage{hyperref}  \begin{document} \immediate\write18{pdflatex "article sample"} \MyLTXinputExample{article sample} \end{document}   How to prevent book class from vertically justifying the contents? In other words, I want to use the book class but its output (only the justification is under consideration) must look like the output that article class produces. iBooks preview not working? I recently converted one of my books into an iBooks format using Author. However when I connected to my iPad and went into 'preview', I saw my device, clicked it, but the 'preview' button to enable the previewing process was faded and I could not click it. Has anyone actually used the preview feature enough to give me some help? Thanks! How to install mysql? Allowing users to compile / run PLSQL and SQL As a DBA - assuming my users are knowledgeable with PLSQL and SQL - why would I not grant my users privileges to compile and run their own PLSQL code. We have an MI database environment where the data has undergone ETL. The tables contain a large numbers of rows but not necessarily large rows in size. The analysis - will be - I assume of calculus in nature. The users are wanting to run their own code on the data for the purposes of ad-hoc analysis - within their own schemas. They come from a SAS background which from my understanding has allowed them to write and run their own analysis of data. Albeit, SAS runs on its own dataset - extracted from Oracle or elsewhere.  In my opinion this is a dangerous set-up - but without answering my own question - what are the pitfalls? Open the default browser in Ruby In Python, you can do this:  import webbrowser webbrowser.open_new("http://example.com/")   It will open the passed in url in the default browser  Is there a ruby equivalent? Why gpedit and the corresponding registry entries are not synchronized? How to install CUDA 8.0 on Ubuntu 16.04 with Nvidia GeForce GTX 1080 I am attempting to install CUDA 8.0 within Ubuntu 16.04 for the Nvidia GeForce GTX 1080. I had CUDA 7.5 installed, but it did not appear to be compatible with the GTX 1080. I downloaded the .run installer from Nvidia's developer page, but the installation fails and outputs the following to a nvidia-installer.log     An NVIDIA kernel module 'nvidia-drm' appears to already be loaded in     your kernel.  This may be because it is in use (for example, by an X     server, a CUDA program, or the NVIDIA Persistence Daemon), but this     may also happen if your kernel was configured without support for     module unloading.  Please be sure to exit any programs that may be     using the GPU(s) before attempting to upgrade your driver.  If no     GPU-based programs are running, you know that your kernel supports     module unloading, and you still receive this message, then an error     may have occured that has corrupted an NVIDIA kernel module's usage     count, for which the simplest remedy is to reboot your computer.   I have rebooted the computer, but that did not resolve the problem. How do I unload the 'nvidia-drm' module so that I can install the 8.0 CUDA? Creating vimrc breaks vim I'm currently logged into a server via ssh with ssh -Y and running a tmux session. If I start vim and run :colorscheme elflord the color scheme is changed. (Although the colors are not exactly what I would expect although they are I think 256 color. If I create a ~/.vimrc file and put a single line colorscheme elflord  in it then when I run vim it shows no color (just white text) and I cannot change the color with the :colorscheme command. How to install with Wubi when it says "Could not retrieve the required disk image files"? piping in real time This is more a conceptual thing than a current problem.  Would it be possible to do this:  tail -f &lt;file&gt; | grep "string" | sed 's/stuff//g' &gt;&gt; output.txt  The problem I'm thinking is that tail -f never terminates so it won't progress in the command. I'm trying to read and output a file in real-time. If this doesn't work how would I do it? One of my bank accounts earned $1.50 for the entire year.  Because the amount is under $10 they did not send a 1099-INT form.   Is this bank policy or IRS policy?  Does that $1.50 need to be reported?  I'm not worried about the difference that this small amount makes on my taxes bur rather what is legally required. Why can't a CNAME record be used at the apex (aka root) of a domain? If we have two circles in the plane described by $(x_1, y_1, r_1)$ and $(x_2, y_2, r_2)$ we can determine if they are completely disjoint by simply:  $$(x_1 - x_2)^2 + (y_1 - y_2)^2 &lt; (r_1 + r_2)^2$$  Assume this is not the case, we now want to know if one completely overlaps the other.  (That is: if the second circles interior is a subset of the first circles interior.)  If $(x_1, y_1) = (x_2, y_2)$ than we can trivially compare radii, so lets assume their centers are distinct.  The way I have imagined is to create a parametric equation of the line that connects the two centers:  \begin{align} x_p(t) &amp;= x_1 + t(x_2 - x_1) \\ y_p(t) &amp;= y_1 + t(y_2 - y_1) \end{align}  Then we calculate the two line segments (represented as two pairs of t values) where the circles intersect this line.  One is a subset of the other if and only if the corresponding circles are subsets of each other.  Is there a simpler approach I am overlooking? On the photos where the lens flare is present, my Nikon D7000 is drawing strange labyrinth-looking artifacts. Here's an example.  The first image is a screenshot of a little part of the original photo zoomed 2:1 in Lightroom.  The second image is the same photo with Lightroom's contrast, clarity and sharpening set to the maximum to make the labyrinth pattern more visible.      This affects only some of the photos presenting lens flare. Here, for instance, the lens flare is present and light conditions are very close to the first photo, but there is no labyrinth pattern, only usual noise (screenshot of a part of a photo at 1:1 with contrast, clarity and sharpening set to the maximum):    Notes:   I can see this pattern only on some of the photos when the sun is in the frame or nearly in the frame. It is present with any lens I tested. The actual photo was shot at f/8, ISO 200, 1/640 s. I've seen this pattern in photos shot at ISO 100 as well. The photo is in RAW format, so this is not a JPEG artifact.   What is that? How do I avoid it?