How does my tablet know when I open the cover?
How do Android tablets use magnet to auto-lock the device?
Is there a Ubuntu sanity check? Is there a standard procedure to 'unit test' an Ubuntu system against the deb packages?  Assume, a system has ubuntu-desktop installed according to the package manager. Can I find out, whether the file system has all the files in ubuntu-desktop and dependencies?   related question: Why is 8 so special? I have been reading about multi-dimensional numbers, and found out that it's been proven that the Octonions are the composition algebra of the largest dimension. I was wondering why, despite having infinitely many different dimensions of numbers, the only composition algebras are of 1, 2, 4, and 8 dimensions. What's so special about 8? Dual monitor setup, why does NVidia 340 Prime only detect one monitor? How do I install the latest OpenOffice? What i did?   [root@mdfdevha1 ~]# Group_ID=`/opt/keycloak/bin/kcadm.sh get groups -r TEST`  [root@mdfdevha1 ~]# echo $Group_ID [ { "id" : "57c86153-11ba-4d19-aafb-9903ee00086b", "name" : "Admin_UserGroup", "path" : "/Admin_UserGroup", "subGroups" : [ ] } ] [root@mdfdevha1 ~]# SURE_USER_ID=`echo $Group_ID | cut -d : -f2 | awk -F\" '{print $2}'` [root@mdfdevha1 ~]# echo $SURE_USER_ID 57c86153-11ba-4d19-aafb-9903ee00086b   In this case i am able to get the id but my requirement little bit complex  I run below command   [root@mdfdevha1 ~]#  Group_ID=`/opt/keycloak/bin/kcadm.sh get groups -r My_Realm`   and then   [root@mdfdevha1 ~]# echo $Group_ID   Output was multiple record in JSON format  [ { "id" : "e27206c0-aeb6-43db-acda-c4ba43233071", "name" : "A1", "path" : "/A1", "subGroups" : [ ] },  { "id" : "89f3bd6a-33a9-4e02-9fe3-eae660c5a6cf", "name" : "Admin_UserGroup", "path" : "/Admin_UserGroup", "subGroups" : [ ] },  { "id" : "cdc2bce5-c3bb-4b88-bdaf-d87b8bb6c644", "name" : "Group104", "path" : "/Group104", "subGroups" : [ ] },  { "id" : "a0d749f2-ab6c-4c27-ad55-3357eaab9527", "name" : "Group105", "path" : "/Group105", "subGroups" : [ ] },  { "id" : "fbf99c34-d50d-408b-8d19-9713f9af3e3a", "name" : "Group106", "path" : "/Group106", "subGroups" : [ ] },  { "id" : "ebd8336f-4017-4fb1-8035-153ae1d9ba37", "name" : "Group201", "path" : "/Group201", "subGroups" : [ ] },  { "id" : "38f4aef7-caf0-4430-9e61-1ae7026e872f", "name" : "Group202", "path" : "/Group202", "subGroups" : [ ] },  { "id" : "436a0f4a-8b1b-4d7d-a014-fcec3513644e", "name" : "Group203", "path" : "/Group203", "subGroups" : [ ] },  { "id" : "41962c5f-e7e9-4748-b81f-e3f1880b78de", "name" : "Sure_Groups", "path" : "/Sure_Groups", "subGroups" : []}]   Now from the above output i want to get the ID where name = Admin_UserGroup.  How can this will achieve ? Who in the DC Universe can stop Superman if he has a breakdown? Is there anything or anyone in the DC universe that can defeat Superman just in case he goes berserk on everybody?  Maybe Batman stores kryptonite in his Cave or something. I don't know if Batman actually has kyptonite, the example was just a theoretical example.  Who can stop Superman if needed, and how? Are there any hash outputs not produced by the MD5 hash function? I need to use it as a placeholder for an empty hash while comparing two hashes. Disable StringBuilder optimisation in javac Suppose one is trying to find the radius of convergence of  $$ \exp(x)=\sum\limits_{k=0}^{\infty} \frac{x^k}{k!} $$  This "proof" was given in the lecture: $$ \begin{align} r =&amp; \frac{1}{\limsup\limits_{n \rightarrow \infty}\sqrt [n]{|a_n|}} \\ =&amp; \frac{1}{\limsup\limits_{n \rightarrow \infty}\sqrt [n]{\frac{1}{n!}}} \\ =&amp;\lim\limits_{n \rightarrow \infty} \sqrt [n]{n!}\\ r=&amp; \infty \end{align}$$  Other proofs involving the ratio test also seem to inspect the convergence of $\frac{1}{k!}$ instead of $\frac{x^k}{k!}$. Why is one allowed to substitute $\frac{1}{k!}$? Wires do not connect in Circuitikz I've been trying to use relative coordinates to make my drawings more precise but it seems I don't know how the command \node works since I've been having this problem while connecting a circuit element to another:    I'm trying to eliminate the blank between the two wires.  This is the minimal code:  \documentclass{book} \usepackage[siunitx,RPvoltages]{circuitikz} %Circuit Schematics/Diagram \usetikzlibrary{arrows,shapes,calc,positioning} \begin{document}     \begin{circuitikz}             \path (0,0) coordinate (C);             % Comparatore             \path (C) + (0,-1) + (1,0) coordinate (com) node[above]{};             \path (com) + (1.5,-1) node[op amp] (comp) {};             % Collegamenti Comparatore             \node (G1) at ([shift=({-1.3cm,0cm})]comp.-) {};             \draw (G1) -- (comp.-);             \node (G2) at ([shift=({-1.3cm,0cm})]comp.+) {};             \draw (G2) -- (comp.+);             \draw (C) -- (G1); % Collegamento Rettificatore - Comparatore         \end{circuitikz} \end{document}   Thanks for any help! How do I find the particular solution of this second order inhomogenous differential equation? (Using undetermined coefficients).  $y''-4y'+5y = 4e^{2x} (\sin x)$  I can find the generel homogenous solutions but I need help for the particular. Write a number with two decimal places SQL Server Expanding code in etoolbox's \ifblank I am trying to use the etoolbox \ifblank (and its cousin \notblank), but I want to expand any macros in its test statement.  For example:  \documentclass{article} \usepackage{etoolbox}  \begin{document}  \newtoggle{longformt} \newcommand{\longform}{\toggletrue{longformt}} \newcommand{\iflong}[2]{\iftoggle{longformt}{#1}{#2}}  \newcommand{\quoteifnotblank}[1]{%     \notblank{#1}{``#1''}{}% }  % Try commenting this line. \longform  This should be completely blank if the form is short: \quoteifnotblank{\iflong{Some long quoted text}{}}  \end{document}   The problem here is that \notblank sees its argument of \iflong{Some long quoted text}{} as a string, not as code to be expanded, so the quotes always appear.  How do I expand arguments before they are passed to \notblank? C# Interfaces. Implicit implementation versus Explicit implementation What are the differences in implementing interfaces implicitly and explicitly in C#?  When should you use implicit and when should you use explicit?  Are there any pros and/or cons to one or the other?    Microsoft's official guidelines (from first edition ) states that using explicit implementations are not recommended, since it gives the code unexpected behaviour.  I think this guideline is very valid in a pre-IoC-time, when you don't pass things around as interfaces.  Could anyone touch on that aspect as well? This is a follow-up to .     When I click a link to an SE site in the Android app, it gives me an "open with" pop-up that has two options:         Chrome   Stack Exchange         I can then choose to open SE posts like this "Just once" or "Always."      The problem is that when I set the SE app to "always," and I click "open in browser,"   Except, the app crashes when trying to open it in browser.  LogCat (just right after selecting "Open in browser")  01-22 18:03:36.354: E/AndroidRuntime(16064): FATAL EXCEPTION: main 01-22 18:03:36.354: E/AndroidRuntime(16064): Process: com.stackexchange.marvin, PID: 16064 01-22 18:03:36.354: E/AndroidRuntime(16064): java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.stackexchange.marvin.utils.Helpers.getNonMarvinViewIntent(Helpers.java:452) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.stackexchange.marvin.ui.question.QuestionDialog$1.onClick(QuestionDialog.java:39) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:1108) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AdapterView.performItemClick(AdapterView.java:310) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AbsListView.performItemClick(AbsListView.java:1145) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AbsListView$PerformClick.run(AbsListView.java:3066) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.widget.AbsListView$3.run(AbsListView.java:3903) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.os.Handler.handleCallback(Handler.java:739) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.os.Handler.dispatchMessage(Handler.java:95) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.os.Looper.loop(Looper.java:148) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at android.app.ActivityThread.main(ActivityThread.java:5417) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at java.lang.reflect.Method.invoke(Native Method) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 01-22 18:03:36.354: E/AndroidRuntime(16064):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)   I suspect it's related to , but not sure.  Specs:   Device model: Nexus 5 Android version: Android 6.0.1 SE app version: 1.0.82 (beta) Installed browser: Chrome 47.0.2526.83 (latest at current writing) Why do I get 'HDIO_GET_IDENTITY failed' message when booting with external usb hard drive? I've installed Ubuntu 11.10 on an external USB (2.0) Hard Drive (/dev/sdb1) but when Ubuntu starts I get a message that says:     ata_id[279]: HDIO_GET_IDENTITY failed for '/dev/sdb': Invalid argument   where I made a mistake? The first HD contains Windows 7 (the official OS of my packard bell notebook). Can I use a 23 W CFL in a fixture that's rated for a 60 W incandescent? I have a lamp that is rated at 60 Watts for an incandescent bulb with a disclaimer to use a 13 Watt bulb instead when using a CFL replacement. Do I really need to respect that disclaimer? Would not a 23 Watt CFL be just as safe to use? It still draws less power than a 60 Watt incandescent, right? I have complicated math expression:    Vertical spacing between text and fraction line is too small. I tried to define new \frac command (with amsmath package) with adjustable vertical spaces. As you can see, the result is not satisfying:    \documentclass[a4paper,fleqn,leqno]{article} \usepackage{polyglossia} \usepackage{color,pifont,fontspec} \usepackage[top=2.54cm,bottom=2.54cm,left=2.54cm,right=2.54cm]{geometry} \usepackage{tikz,tikz-3dplot,graphicx} \usepackage{mathtools,breqn,amsmath} \usepackage[fontsize=12]{scrextend} \usepackage{array,multirow} \usepackage{pgfplots} \DeclareMathSizes{12}{14}{14}{10} \newcommand{\myfrac}[3][0pt]{\genfrac{}{}{}{}{\raisebox{#1}{$#2$}}{\raisebox{-#1}{$#3$}}} \begin{document} \begin{dmath*}[breakdepth={0},style={\mathindent=0pt},spread={10pt}] {n=\myfrac[3pt]{\myfrac[3pt]{0,0625N+0,0215}{2}-0,043}{\myfrac[3pt]{\myfrac[3pt]{\scriptstyle 0,0625N+0,0215}{\scriptstyle 2}-0,043}{\myfrac[3pt]{\scriptstyle N}{\scriptstyle 2}-1}+0,0215}} \end{dmath*} \end{document}   How can I enlarge verticall spacing in whole fraction? Bounded in Probability and smaller order in probability I wanted to prove that if $X_n$ is bounded in probability and $Y_n = o_p(X_n)$, then $Y_n \rightarrow 0$ in probability   I  know the following definitions that is $X_n$ is bounded in probability meaning that   $P(|X_n|&lt;M)&gt;1-\epsilon$  and I know that $Y_n = o_p(X_n)$ implies that $Y_n/X_n \rightarrow0$ in probability There is a button in the "basic math assistant" which wraps highlighted text in chosen brackets. Is there no keyboard command for this?