I have:  $ find 1 2 -printf '%i %p\n' 40011805 1 40011450 1/t 40011923 1/a 40014006 1/a/e 40011217 1/a/q 40011806 2 40011458 2/y 40011924 2/a 40013989 2/a/e 40013945 2/a/w   I want:  &lt;inode&gt;  &lt;path&gt; any      2 40011450 2/t 40011458 2/y any      2/a 40014006 2/a/e 40011217 2/a/q 40013945 2/a/w   How do do it?
I'm trying to merge two directory trees that have many common elements but also each have elements that are only present in one of the two trees. The main issue I am having is that when mv encounters two sub-directories with the same relative paths it either keeps the source (with -f) or the destination (with -n) but I can't make it take the union of both sub-directories. I could of course use rsync with --remove-source-files but this will actually copy the data and then delete the old files as opposed to a true move. The two directory trees contain several hundred GB of data and are both on same partition so I would love to do a true move if possible for the sake of time.   Right now I have find * -type file -exec mv -n {} /destination/{} but this only moves  files from the source to the destination when the target directory already exists. I can preface this command with something like mv -n * /destination/ but this only brings over the top level directories. Is there any way to do this in a single line? I could  always write a script to check if the directory exists before copying the file but this seems like such a basic task, it seems like there should be an easier way.
Why doesn't **sort** sort the same on every machine? Using the same sort command with the same input produces different results on different machines.  How do I fix that? What is the difference between correlation, causation and prediction? Suppose we have a set of events $\Omega$, containing events $A$ and $B$. My econometrics professor tried to distinguish the following three terms today.    Causation --- $A$ causes $B$ if the occurrence of $A$ always leads to another specific outcome $B$. For example, clapping my hands causes a sound to be emitted.  Prediction --- $A$ predicts $B$ if on average, $B$ is the expected outcome from $A$ occurring. In other words, whereas causality is deterministic, prediction is probabilistic. For example, studying for a test would predict doing well on the exam. But there's no guarantee.   Correlation --- $A$ and $B$ are correlated if when one occurs the other does too. But there may be some hidden variable causing both.    Are these distinctions meaningful? Or did he make these terms up?   My Questions   What is the difference between causation and correlation?  Are "causes" always deterministic? Since a few months, on one of the desktop Ubuntu 14.04 systems I use, CPU has regularly been going up to 80-100% for no apparent reason. htop would usually attribute responsability to file system processes, such as nemo or ntfs. To get CPU back down I would kill these process, which in some cases would lead to loss of access to the file system and a consequent restart.  Days ago I noticed that whenever this situation happened another process was always present also using high CPU: mediascanner-service-2.0. Some research lead me to  that simply advised its removal. So I did.  The end result has been unexpectedly positive: not only are the high CPU load episodes gone, the system is altogether much faster. The speed up of the Lens is dramatic: finding an application like Calc now takes 2 seconds at most when previously it took some 20 seconds. Finding a file takes now some 5 seconds, whereas before it took in the order of 30 seconds. Heavy programmes like Eclipse are starting up faster and workspaces are more fluid. There seems to be also an overall reduction in the frequency of disk access.  What is exactly this mediascanner2.0 package? Is it part of Unity 7 or a dependency that gets installed a posteriori? Is it possible to prevent its installation?  Update: following  it is possible to track this package down to indicator-session:  $ sudo aptitude why mediascanner2.0 i   indicator-session         Recommends indicator-applet (&gt;= 0.2) | indicator-renderer i A unity8                    Provides   indicator-renderer                             i A unity8                    Recommends unity-scope-mediascanner2                      pi  unity-scope-mediascanner2 Depends    mediascanner2.0                                  Apparently, mediascanner2.0 (and the Unity 8 shell) are part of the base 14.04 system. Left to answer is the exact function of this rogue package. Comprehensive book on group theory for physicists? I am looking for a good source on group theory aimed at physicists. I'd prefer one with a good general introduction to group theory, not just focusing on Lie groups or crystal groups but one that covers "all" the basics, and then, in addition, talks about the specific subjects of group theory relevant to physicists, i.e. also some stuff on representations etc.  Is Wigner's text a good way to start? I guess it's a "classic", but I fear that its notation might be a bit outdated? SCJP6 regex issue Foreign key constraints failures Given the following tables:  CREATE TABLE `longdescs` (   `comment_id` int(11) NOT NULL AUTO_INCREMENT,   `bug_id` mediumint(9) NOT NULL,   `who` mediumint(9) NOT NULL,   `bug_when` datetime NOT NULL,   `work_time` decimal(7,2) NOT NULL DEFAULT '0.00',   `thetext` mediumtext NOT NULL,   `isprivate` tinyint(4) NOT NULL DEFAULT '0',   `already_wrapped` tinyint(4) NOT NULL DEFAULT '0',   `type` smallint(6) NOT NULL DEFAULT '0',   `extra_data` varchar(255) DEFAULT NULL,   PRIMARY KEY (`comment_id`),   KEY `longdescs_bug_id_idx` (`bug_id`),   KEY `longdescs_who_idx` (`who`,`bug_id`),   KEY `longdescs_bug_when_idx` (`bug_when`),   KEY `comment_id` (`comment_id`),   CONSTRAINT `fk_longdescs_bug_id_bugs_bug_id` FOREIGN KEY (`bug_id`) REFERENCES `bugs` (`bug_id`) ON DELETE CASCADE ON UPDATE CASCADE,   CONSTRAINT `fk_longdescs_who_profiles_userid` FOREIGN KEY (`who`) REFERENCES `profiles` (`userid`) ON UPDATE CASCADE ) ENGINE=InnoDB AUTO_INCREMENT=82727 DEFAULT CHARSET=utf8  CREATE TABLE `trace` (   `id` mediumint(9) NOT NULL AUTO_INCREMENT,   `comment_id` mediumint(9) NOT NULL,   `type` varchar(255) NOT NULL,   `short_hash` char(22) DEFAULT NULL,   `stack_hash` char(22) DEFAULT NULL,   `trace_text` mediumtext NOT NULL,   `quality` double NOT NULL,   PRIMARY KEY (`id`),   UNIQUE KEY `trace_comment_id_idx` (`comment_id`),   KEY `trace_short_hash_idx` (`short_hash`),   KEY `trace_stack_hash_idx` (`stack_hash`) ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8  ALTER TABLE trace ADD CONSTRAINT `fk_trace_comment_id_longdescs_comment_id` FOREIGN KEY (`comment_id`) REFERENCES `longdescs`(`comment_id`) ON UPDATE CASCADE ON DELETE CASCADE; ERROR 1005 (HY000): Can't create table 'bugs4.#sql-4bb_6f1d' (errno: 150)   MariaDB [bugs4]> show warnings;  | Level  | Code | Message | | Warning |  150 | Create table 'bugs4/#sql-4bb_6f1d' with foreign key     constraint failed. There is no index in the referenced table where the referenced columns appear as the first columns.  | | Error   | 1005 | Can't create table 'bugs4.#sql-4bb_6f1d' (errno: 150)                                                                                                                       |   Any idea why I get that error? FYI I looked it up and it appears that it was a bug but not anymore. Find $\lim_{x \to 0} (\frac{\tan(x)}{x})^{\frac{1}{x}}$ Find $$\lim_{x \to 0} (\frac{\tan(x)}{x})^{\frac{1}{x}}$$   My first idea to solve this was to try to evaluate it and then apply the L'Hospital's rule. This is what I managed to achieve: $$\left(\frac{\tan(x)}{x}\right)^\frac{1}{x}=e^{\frac{1}{x}\ln\left(\frac {\tan(x)}x \right)} $$ However, this is problematic, because the L'Hospital's rule is not applicable in the exponent, therefore my transformation was not a good shot. What transformation should I apply to get the desired form? Gamma Distribution out of sum of exponential random variables Stack Exchange iOS app nearing beta We're getting very close to releasing our iOS app on the App Store.  Since the , we have taken on hundreds of users, fixed a lot of bugs, and we have approached feature completion for v1.0.  We're still working on finishing touches and fixing crashes - but there aren't too many of those these days.  We believe we'll have this out in .    Current Alpha Testers:  We want to extend to you a huge thank you for using our app and giving us feedback.  We've made a ton of improvements that filtered through  here on meta.  We're pretty greedy, though, and we want more of your feedback as we get close to beta.  If you've been using the app, please leave an answer to tell us how you think we've done so far.  Don't go easy on us - we want to get this as right as we can before hitting the App Store.  You might even consider telling us how many stars you would give us if we were in the store.  Also, we created a room called  for more casual discussion about the app.  Everyone Else:  The alpha will continue in the interim, and we still .  The invitations are sent out once a week (usually), so if you don't get an invite right away, don't panic.  We'll get to you.  Bugs or feature requests should be reported here on meta and tagged .  Update, 5/1/2014    As of today, the app is submitted for review.  A great big thanks to all our alpha testers!  Your feedback has been invaluable and has truly helped us make the app much better than it would have been without you.  So what now?  Well, we intend to keep the alpha test group around, except now we're considering it the "beta channel".  It's still important to us, particularly since the update cycle through the AppStore is slow.  We'll still roll out updates in the same way that we have been.  We will also from time ask for targeted feedback on specific features.  And, lastly, if you're just now getting here and wished you had signed up for the alpha, feel free to sign up now anyway.  The form is still there, and we may still let in additional users to the beta channel depending on what our "active users" count looks like. If the quotient group $G/N$ be isomorphic to $G_2$, is $G$ isomorphic to $G_1\times G_2$ where $N$ is isomorphic to $G_1$? How to test if a player is near coordinates in 1.13? Option clash when using graphicx and tikz packages The following code fails Option clash for package graphicx, it seems to be an incompatibility between the package graphicx (when the option pdftex is used) and the package tikz.  \documentclass[a4paper,10pt]{book} \usepackage[T1]{fontenc} \usepackage[utf8x]{inputenc} \usepackage{tikz} \usepackage[pdftex]{graphicx}  \begin{document}      The lazy dog...  \end{document}   I am currently working with Debian wheezy (updated as of 10th November 2012), and the latest TeXLive LaTeX distribution included.  Any ideas? If $a,b$ are the roots of the equation $2 x^2 -3 x +1 = 0$, find an equation whose roots are $a/(2b +3)$, $b/(2a +3)$ If $a,b$ are the roots of the equation $2 x^2 -3 x +1 = 0$, find an equation whose roots are $a/(2b +3)$, $b/(2a +3)$   I was practicing quadratic equation questions online but I am stuck on this question.  I found the values of roots $a= 1$, $b= 1/2$ Totally ordering the power set of a well ordered set. Let's say I take a set $S$, where $S$ can be well ordered. From what I understand, one can use that well ordering to totally order $\mathscr{P}(S)$.  How does a body actually use the well ordering of $S$ to construct a total ordering of $\mathscr{P}(S)$?  Perhaps construct is too strong a word. Is there a way to prove that a total ordering of $\mathscr{P}(S)$ just exists, no need to explicitly state what it is, since that might be very difficult. I've always had this question about the pronunciation of Sean.  Is Sean a word from another language? Is it actually not pronounced Shawn and instead it's some sound between Shawn and Seen? Also, why isn't it pronounced as Sawn instead of Shawn, when the word Sean doesn't even have the letter 'h' in it to get that -sh sound?  Bottom line is, why is Sean pronounced Shawn instead of Seen? I am trying to take pictures of large rugs. The rug size is about 10mx5m, and I'm  planning to purchase , and Canon 7D Mark II with Canon EF 50MM F/1.2L USM lens, since we need high quality images.  We want to set up a studio to take giga-pixel quality images of the large rugs for museum conservation purposes  Could you please suggest the best way for mounting the camera to the ceiling, and any other recommendations for my camera/lens setup, and required lighting? It will be  an indoor shoot. Just we want to setup a studio to shoot the large rugs. What is the purpose of wrapping whole Javascript files in anonymous functions like “(function(){ … })()”? Add markdown toolbar to mobile web On the full site, there's that helpful Markdown toolbar above the post box:   This is conspicuously missing in the mobile site:   It's difficult just to get a bracket on my iPad. Backticks aren't even available. If there's a view that really needs it, i vote mobile. Changing left margin in itemize environment of beamer class I can't figure out how to line up the symbols of an itemize environment in beamer with the left part of the main text. In other words, I would like to supress the left margin in beamer itemize lists.  It would be nice if the solution worked with any itemize label defined with  \setbeamertemplate{itemize item}[]   In order to make myself clearer, what beamer produces by default is something like:  Main text. Main text. Main text...    * Item 1    * Item 2    * Item 3    ....   and the desired result is   Main text. Main text. Main text... * Item 1 * Item 2 * Item 3 .... How many possible electromagnetic wavelengths are possible? Disclaimer: Please keep in mind that I am a young highschool student with no background in physics, this research was done in the course of an hour, and my reasoning could very well be wrong.  After a short conversation about color, I did some thinking, and read  The answer claims that there are $\infty^{\infty}$ colors   My first problem is the definition of colors, I'm going to simplify this (although it's not the same thing) as electromagnetic frequencies. This is what I mean when I refer to color in the rest of this question  The problem with $\infty^{\infty}$ colors is that the plank length exists. This causes two problems to arise with $\infty^{\infty}$. If $l_p$ is assumed to exist (as it is), this means the smallest distance in the universe is $l_p$. So, all wavelengths of light can be divided into a set, of the wavelengths produced by objects at $0^{\circ}$ Kelvin to $\infty^{\circ}$ Kelvin. According to this logic, there are simply $\infty$ colors.  Things are complicated further, when you introduce the Plank Temperature ($P_t$). $P_t$ is the theoretical limit temperature of the universe (at least for the purposes of light and color) Because an object hotter than $P_t$ will produce light with wavelengths shorter than $l_p$. This would introduce an upper limit on colors too.  Wouldn't this mean that the total number of possible colors is equal to however many plank lengths difference there is between an electromagnetic wave produced by a 0 degree object and a $l_p$ object? And therefor far less than $\infty$? Does this reasoning make sense at all?