Space after LaTeX commands
No space following macro without argument
How to detect when a variable changes value How can I easily detect when a variable changes value? I would like the execution of the program to break on the debugger whenever a specified variable changes value. Right now I'm using Eclipse's debugger. 14.04 --> 16.04 failed; apt (>= 1.0.1ubuntu2.13)' is not installed I'm trying to figure out how to assign higher priority to one PPA over another PPA. I had a look on bunch of the answers on this forum but none of them solves my problem.  We have two PPA sources on some of our servers which we stick into separate files in /etc/apt/sources.list.d . Some of these repos provide same packages (in terms of names) but different versions and possibly different binaries. Is there a way how we can PRIORITISE one repo over another ?  I read apt_preferences tutorial but it could not be more obscure and didn't find the answers for my question. Here is the situation. WE have the following sources:  $ ls -l /etc/apt/sources.list.d  total 12 -rw-r--r-- 1 root root 66 Jan  2 16:50 nginx-source.list -rw-r--r-- 1 root root 84 Jan  2 16:49 ruby-ng-experimental-source.list   where nginx-source.list content is:  deb     http://ppa.launchpad.net/nginx/stable/ubuntu precise main   and ruby-ng-experimental-source.list content is:  deb     http://ppa.launchpad.net/brightbox/ruby-ng-experimental/ubuntu precise main   Both of these sources provide nginx-full package of different versions etc. When I list the priorities ruby-ng-experimental-source.list is on top of output hence nginx-full is installed from that repo:  $ apt-cache policy nginx-full                                  nginx-full:   Installed: 1:1.2.3-1~38~precise1   Candidate: 1:1.2.6-1~43~precise1   Version table:      1:1.2.6-1~43~precise1 0         500 http://ppa.launchpad.net/brightbox/ruby-ng-experimental/ubuntu/ precise/main amd64 Packages  *** 1:1.2.3-1~38~precise1 0         100 /var/lib/dpkg/status      1.4.1-1ppa0~precise 0         500 http://ppa.launchpad.net/nginx/stable/ubuntu/ precise/main amd64 Packages      1.1.19-1ubuntu0.1 0         500 http://mirror.rackspace.co.uk/ubuntu/ precise-updates/universe amd64 Packages      1.1.19-1 0         500 http://mirror.rackspace.co.uk/ubuntu/ precise/universe amd64 Packages   How do I prioritize repo listed in nginx-source.list over the one which is on top of the list now ? I tried something like this:  $ cat /etc/apt/preferences Package: nginx-full Pin: origin http://ppa.launchpad.net/nginx/stable/ubuntu Pin-Priority: 1000  Package: nginx-full Pin: origin http://ppa.launchpad.net/brightbox/ruby-ng-experimental/ubuntu Pin-Priority: 100   But that has changed priorities of both sources to the same number - or something like that ? So this has NOT changed the priorities and nginx-full is still being installed form the brightbox PPA  $ apt-cache policy nginx-full   nginx-full:   Installed: 1:1.2.3-1~38~precise1   Candidate: 1:1.2.6-1~43~precise1   Package pin: (not found)   Version table:      1:1.2.6-1~43~precise1 1000         500 http://ppa.launchpad.net/brightbox/ruby-ng-experimental/ubuntu/ precise/main amd64 Packages  *** 1:1.2.3-1~38~precise1 1000         100 /var/lib/dpkg/status      1.4.1-1ppa0~precise 1000         500 http://ppa.launchpad.net/nginx/stable/ubuntu/ precise/main amd64 Packages      1.1.19-1ubuntu0.1 1000         500 http://mirror.rackspace.co.uk/ubuntu/ precise-updates/universe amd64 Packages      1.1.19-1 1000         500 http://mirror.rackspace.co.uk/ubuntu/ precise/universe amd64 Packages   Anyone has any idea how to achieve what I'm trying to do ? How do I answer "Where do you work?" What are the main purposes to ask someone 'Where do you work?' apart from to find out the type of place he or she works in?  I can answer:     I work in a shop.   I work in a hospital.   I work in an office.   But what other things can (or should) I use as a reply to this question?    Extra question:  sometimes I see     I work at a shop.    I work at a hospital.    I work at an office.   What's the difference between 'at' and 'in' in this case? Should I use the first or last bits from a SHA-256 hash? I have the need for a hexadecimal token that is smaller than the normal length of the hexadecimal representation of a  hash.  Should I take the first bits or the last bits? Which of them contain the most entropy? MacBook Pro locked with Find My Mac and won't let me boot Page title with substitution on views page I have a view page that requires a dynamic page title. It is a simple substitution of the label field.  If I use {{ label }} it works fine for the title displayed on the page, but it doesn't substitute the label for the actual page title (in meta)  I was able to fix this by using hook_views_post_render using the following code  // Set the route title. $route = \Drupal::routeMatch()-&gt;getCurrentRouteMatch()-&gt;getRouteObject(); $route-&gt;setDefault('_title', $title);  $view-&gt;setTitle($title);   However, the title only works if the page is not cached. For the cached pages, the page title is missing. This feels like a bug in drupal, but I am hoping that there is a simple way to get this done. Choose a default app for opening files with no extension? Is it possible to set a default application to open files with no extension?  I'm not referring to files with hidden extensions, but those completely lacking an extension -- e.g. README, CHANGELOG, mbox, etc.  "Open With" => "Change All" on these files doesn't work, returning the error shown below:    Ideally, I would like the system to try opening all such files in TextMate.  I know I can drag files onto Dock icons to open them in specific apps, but I'm looking for a more seamless solution than that (especially since I have my Dock auto-hide, which makes it much more cumbersome).  I am familiar with the  QuickLook plugin that can enable QuickLook for some of these files, but I would prefer a solution with selecting/copying/editing capabilities. Asking users to accept answer when they comment that it answers their question Understanding reference counting with Cocoa and Objective-C I'm just beginning to have a look at Objective-C and Cocoa with a view to playing with the iPhone SDK. I'm reasonably comfortable with C's malloc and free concept, but Cocoa's references counting scheme has me rather confused. I'm told it's very elegant once you understand it, but I'm just not over the hump yet.  How do release, retain and autorelease work and what are the conventions about their use?  (Or failing that, what did you read which helped you get it?) strptime() equivalent on Windows? Is there a good equivalent implementation of strptime() available for Windows?  Unfortunately, this POSIX function does not appear to be available.   - summary: it converts a text string such as "MM-DD-YYYY HH:MM:SS" into a tm struct, the opposite of strftime(). Let $A$ and $B$ be $n\times n$ matrices such that $ABAB=0_{n\times n}$.  Can we conclude that  $BABA$ must be  $0_{n\times n}$?   I fail to give a counterexample when $n=2$， so I guess the answer is "yes" How can gravitions exist without violating GR? update-java-alternatives vs update-alternatives --config java On Ubuntu 12.04 LTS I have installed Sun's JDK7, Eclipse, and the Arduino IDE. I want the Arduino to use OpenJDK 6 and want Eclipse to use Sun's JDK 7.   From my understanding I need to manually choose which Java to use before running each application. This led me to the update-java-alternatives -l command. When I run this I only see the following:   java-1.6.0-openjdk-amd64 1061 /usr/lib/jvm/java-1.6.0-openjdk-amd64   but when I run update-alternatives --config java I see the following:   *0  /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   auto mode 1  /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java   manual mode 2  /usr/lib/jvm/jdk1.7.0/bin/java                   manual mode 3  /usr/lib/jvm/jre1.7.0/bin/java                   manual mode   I don't understand why the update-java-alternatives doesn't display the same 3 options. I also don't understand how to switch between OpenJDK6 and JDK7. How I can go about using the OpenJDK6 for Arduino development and Sun JDK7 for Eclipse/Android development? Is my solution correct for solving $\cos(z)=2$, $z\in \mathbb{C}$ When should we consider a dataset as imbalanced? I'm facing a situation where the numbers of positive and negative examples in a dataset are imbalanced.  My question is, are there any rules of thumb that tell us when we should subsample the large category in order to force some kind of balancing in the dataset.  Examples:   If the number of positive examples is 1,000 and the number of negative examples is 10,000, should I go for training my classifier on the full dataset or I should subsample the negative examples? The same question for 1,000 positive example and 100,000 negative. The same question for 10,000 positive and 1,000 negative. etc... We are all told at school water vapour and carbon dioxide are the top two greenhouse gases, and that they absorb thermal infra red radiation, trap heat and warm up the Earth. My question is how do they do that? Why can't Oxygen or Nitrogen or any other gas not absorb infra red radiation as well as water vapour or CO2? Solve $\lim_{x\to 0} \frac{\sin x-x}{x^3}$ I'm trying to solve this limit     $$\lim_{x\to 0} \frac{\sin x-x}{x^3}$$   Solving using L'hopital rule, we have:  $$\lim_{x\to 0} \frac{\sin x-x}{x^3}= \lim_{x\to 0} \frac{\cos x-1}{3x^2}=\lim_{x\to 0} \frac{-\sin x}{6x}=\lim_{x\to 0} \frac{-\cos x}{6}=-\frac{1}{6}.$$  Am I right?  I'm trying to solve this using change of variables, I need help.  Thanks  EDIT  I didn't understand the answer and the commentaries, I'm looking for an answer using change of variables. What are the integer solutions to $a^{b^2} = b^a$ with $a, b \ge 2$ Why doesn't Doctor Strange remove the Infinity Gauntlet from Thanos? Doctor Strange seemingly has the ability to open portals wherever he wants. We see at the beginning of Infinity War what happens when he closes a portal and someone isn't fully through it.  Is there any reason why he can't open a portal around the left-elbow of Thanos, and then close it?  I realize that Thanos probably wouldn't allow this to happen normally,      but when he is mostly asleep, and Tony and Spider-Man are pulling on the gauntlet, Doctor Strange has ample opportunity, and plenty of space to just sever Thanos' arm.   Why doesn't he?