With regards to:   The link fully answered the question right from the boost documentation. What is wrong with it?
It was a useful answer.
I use youtube-dl to download videos for watching later offline. Usually, it works fine. However, due to frequent changes on the video sites, it sometimes requires a quick update. It wasn't a problem before on 13.04 but after upgrading to 13.10, I get  # youtube-dl -U It looks like you installed youtube-dl with a package manager, pip, setup.py or a tarball. Please use that to update.   I tried updating it via apt-get but there is no new package. So the app's update mechanism has been disabled and the maintainers aren't keeping up, what is the solution? How do I update it?  And why was it changed at all? It was updating a package manager version just fine in raring.   I'm already running into compatibility problems.   $ youtube-dl "http://vimeo.com/55784152" [vimeo] 55784152: Downloading webpage [vimeo] 55784152: Extracting information ERROR: Unable to extract info section; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.   QUICK UPDATE:  As requested,  # type youtube-dl youtube-dl is hashed (/usr/bin/youtube-dl)  # apt-cache policy youtube-dl youtube-dl:   Installed: 2013.08.29-1   Candidate: 2013.08.29-1   Version table:  *** 2013.08.29-1 0         500 http://pl.archive.ubuntu.com/ubuntu/ saucy/universe amd64 Packages         100 /var/lib/dpkg/status Let $X$ and $Y$ be independent $N(0; 1)$ random variables. Let $Z = \sqrt{X^2+Y^2}$.  (a) Derive the marginal pdf of $Z$ and then using the marginal pdf to compute ${\rm E}[Z^2]$  (b) Can you propose a different way other than that in (a) to compute ${\rm E}[Z^2]$  (c) Compute ${\rm E}[Z]$.  This is the whole question that I was asked. I can do (c) but I don't know how to find the marginal pdf of $Z$ with the given information and can't seem to find any formulas. Any help would be appreciated. "Activity" tab for the Community user's network profile sometimes leads to a server error What functionality do 'marks' offer in the El Capitan Terminal? Since upgrading to OS X El Capitan, I've noticed a change in the Terminal: Executed lines show an opening bracket on the left, and a closing bracket on the right, as shown in this screenshot:    Similar questions have been asked here:          Some of the questions are referring to these brackets as marks, and the Terminal's Edit menu has a couple of entries related to marks, for example:   Edit > Marks > Mark as Prompt and Send Return Edit > Clear to Previous Mark Edit > Navigate > Jump to Previous Mark     Is there a summary of what these marks can be used for? I have not seen any reference to this new feature in any of the El Capitan feature overviews. Are PDO prepared statements sufficient to prevent SQL injection? Let's say I have code like this:  $dbh = new PDO("blahblah");  $stmt = $dbh-&gt;prepare('SELECT * FROM users where username = :username'); $stmt-&gt;execute( array(':username' =&gt; $_REQUEST['username']) );   The PDO documentation says:     The parameters to prepared statements don't need to be quoted; the driver handles it for you.   Is that truly all I need to do to avoid SQL injections?  Is it really that easy?  You can assume MySQL if it makes a difference.  Also, I'm really only curious about the use of prepared statements against SQL injection.  In this context, I don't care about XSS or other possible vulnerabilities. Copy Physics To Multiple Objects Low-RAM Linux Distro Specifically for serving static sites If H is a subgroup of a group G and K is a normal subgroup of G the show that K is a normal subgroup of HK. Note K is a normal subgroup of HK  I thought I could just prove K is a subset of HK and vice versa so as to prove it a normal subgroup but then how to do this I have no idea because I keep getting hk element again while trying to do so.  I just tried to implement the steps to find HK is a subgroup of G. I just need to check the reasoning in my proof is correct, I think it is valid although I'm not totally convinced because I can't follow the logic; does proving that $x$ is an integer prove that $ac|bd$?  Theorem: Let $a$, $b$, $c$, $d$ be integers. If $a|b$ and $c|d$, then $ac|bd$.  Proof: $aj=b$ and $ck=d$ for integers $j$, $k$. Then, $ac|bd$ implies $acx=ajck$ and thus $x=jk$ for some $x$. Since the product $jk$ is an integer, $x$ is an integer and thus $acx=ajck$ and thus $ac|bd$. Folland, "Real Analysis", Chapter 5.3, Exercise 36. For me the distinction between sites is purely topical. I get that there's a right and a wrong place to ask questions, but I regularly ask questions across a number of sites. They all log me in (in a weird sort of way), and now there's the global inbox.  I've read that there's a feed  and that there's a  but neither of these are what I want.  What I'd like is to have an RSS feed from my global inbox, i.e. to include notification of updates to my public questions, answers, comments. Is this possible? SQL MAX of multiple columns? How do you return 1 value per row of the max of several columns:  TableName  [Number, Date1, Date2, Date3, Cost]   I need to return something like this:  [Number, Most_Recent_Date, Cost]   Query? How to Set a Short User Password in macOS Mojave and Later (10.14+) I just installed macOS Mojave and put in my usual short desktop-only password I've been using for years (yes, you read that right). Now though, the operating system rejects setting a password less than 4 characters. It also does not allow having no password at all.  I am completely comfortable using the shell if need be.  How can I change the password policy to allow quite short passwords? Mechanism of Screenshot Basically I with my team are figuring out a way to block screenshots taken on our corporation's computers (Mac mostly). I have searched it extensively and found that there is something called Screen buffer which is being accessed by any screenshot taking software (eg. Snipping Tool etc). I tried to find the exact mechanism and the actual implementation of such softwares but with no luck. Also I found out that Netflix uses some kind of technology which corrupts screenshot image and blackens it. I did not find any actual mechanism or implementation to study it further. I also came across something called Hardware overlays but did not understand it properly in order to use it for actual implementation. I have considered a way to edit scancode maps in registry but I am looking for a more general way. I read a few articles for apple's FPS though. Can somebody please guide me through this? Some good resources for the same would be highly appreciated. Any particular or relevant forums or subs to discuss this are also welcome $\int_0^\infty \frac{\log(x)}{x^2+\alpha^2}$ using residues I'm trying to find $\int_0^\infty \frac{\log(x)}{x^2+\alpha^2}dx$ where $\alpha&gt;0$ is real.  My approach was to take an integral along the real line from $1/R$ to $R$, around the circle counterclockwise to $-R$, along the real line to $-1/R$, and then around the circle clockwise to $1/R$.  I have encountered 2 problems with this:   This path encloses one pole, at $z=\alpha i$.  I found the residue at $z=\alpha i$ to be $\frac{\ln(\alpha)+i\pi/2}{2\alpha i}$.  However, this gives me that $\int_0^\infty \frac{\log(x)}{x^2+\alpha^2}dx=\frac{\pi(\ln(\alpha)+i\pi/2)}{2\alpha}$.  Since I have a real function integrated over the real line, there cannot be an imaginary part.  Where did I go wrong?  (Also, doing a few examples, the correct answer seems to be $\frac{\pi\ln(\alpha)}{2\alpha}$, the same as I have but without the imaginary part.) At first chose my path so instead of going all the way around the upper semicircle, it only went 3/4 of the way around, as I wanted to avoid anything that might go wrong with the discontinuity of $\log(x)$ at the negative real axis.  When I do this, though, I get a different answer than before (the denominator of the fraction is $\alpha(1-e^{3\pi i/4})$ instead of $2\alpha$.  What am I doing wrong that gives me different answers? I know that VARIABLE=value creates an environment variable, and export VARIABLE=value makes it available to processes created by the current shell. env shows the current environment variables, but where do they live? What comprises an environment variable (or an environment, for that matter)? proving the inequality $\triangle\leq \frac{1}{4}\sqrt{(a+b+c)\cdot abc}$ How to wait in bash for several subprocesses to finish and return exit code !=0 when any subprocess ends with code !=0? For example, in a novel, if someone is so powerful that no one can stop him, something like this would be said:     He [insert word] in the continent [or some other location].   "Moved unhinderedly" somewhat fits it, but it doesn't really seem like the right term.  The word I'm looking for describes a few things:   Should have an implication that the person himself is powerful That person can go wherever he wishes to, and cannot be stopped because of his strength That person can do whatever he wishes to, and like above, cannot be stopped because of his strength   The other word I have is "swept", i.e.:     He swept through the continent.   I used "swept" because when you sweep the floor, nothing stops you and everything is swept away, similar to the example. However, the dictionary definitions don't match up, so that isn't the word either.  Any suggestions? indefinite article before proper names Kafka, discovered in the 1920s by the Expressionists, damned by the Nazis in the 1930s and by the Marxists at more or less the same time, was reinvented after World War II by the French Existentialists. They saw in him the father of Angst and the Angst for the father: an Albert Camus before his time.   Can you tell me what the purpose of using the indefinite article before the proper name is in the sentence above. What it be a mistake to write just "Albert Camus" without the article?