It would be nice if we can spread the world, by just one click - email.
My two main questions:  Are all URLs that include your User Id tracked?  Can the visitors who use the tracked URLs have Stack Exchange accounts?   Specifically: Recently the ability to earn badges for sharing links to posts on Stack Exchange sites . I'd like to know when and how this tracking works. It's clear that if you go to a question, and make use of the link button, you will get a URL with your User ID that will be tracked if a visitor uses it to get to SO. For example, let's use  as an example. It's regular URL is:  https://stackoverflow.com/questions/309300/defend-php-convince-me-it-isnt-horrible  If you go to that page and use &quot;save link as&quot; in the link section of the question you will be given a tracked url with your User ID:  https://stackoverflow.com/q/309300/[USER ID]  My question is, are there other URLs that would be tracked? All of the following URLs take you to the Question / Answer, but are they tracked? For example what if I just tack my User ID onto the long url?  https://stackoverflow.com/questions/309300/defend-php-convince-me-it-isnt-horrible/[USER ID]  What if I add my User ID to an answer URL?  https://stackoverflow.com/questions/309300/defend-php-convince-me-it-isnt-horrible/309622#309622/[USER ID]  or even  https://stackoverflow.com/q/309622/[USER ID]   Is there a way to know that a URL is being tracked? Is there some sort of format to follow? Are the only tracked URLs the ones provided in the Question links? Finally, does this sentence from the blog post mean that visitors cannot have an account?  Also, the tracked IPs must originate from outside our existing network.
How to write conditional equations with one-sided curly brackets Replace environment variables in a file with their actual values? Is there an easy way to substitute/evaluate environment variables in a file? Like let's say I have a file config.xml that contains:  &lt;property&gt;     &lt;name&gt;instanceId&lt;/name&gt;     &lt;value&gt;$INSTANCE_ID&lt;/value&gt; &lt;/property&gt; &lt;property&gt;     &lt;name&gt;rootPath&lt;/name&gt;     &lt;value&gt;/services/$SERVICE_NAME&lt;/value&gt; &lt;/property&gt;   ...etc. I want to replace $INSTANCE_ID in the file with the value of the INSTANCE_ID environment variable, $SERVICE_NAME with the value of the SERVICE_NAME env var. I won't know a priori which environment vars are needed (or rather, I don't want to have to update the script if someone adds a new environment variable to the config file). Thanks! Are there wizarding schools in the rest of the "magical" world? Are there other schools for witches and wizards in the rest of the world? In the books they only speak of 3 schools, but what about Asian or American people?  And even more, were they affected by the events happening in Europe? How to install WhatsApp? biblatex: separator for citing multiple sources, some of them with page, some not I'm using biblatex for my references.  Normally, if I use \cite{source1, source2, source3}, I get a citation like  [3, 45, 98]   If I now want to give a page number for one of them, it looks confusing imho, as I should get (did not try it out up to now, honestly)   [3, 45, 78, p. 23f, 98]   So imho it would make sense to change one of the separator from a comma to e. g. a semicolon like:  [3; 45; 78, p. 23f; 98]   Question 1: Does that make sense, or are there other conventions for citing sources with and without page numbers together?  (Up to now I collected the citations without page number in one cite command and added singular \cite[][p. xy]{} commands for those with page numbers., so I'd get:   [3, 45, 98][78, p. 23f]   )  the \cites[]{}[]{}[]{} could also do that, but it also uses the same separators for entries and postnotes.  Question 2: How could I change the separator globally for those number-citations from comma to semicolon in biblatex? Inverse of a Positive Definite Why do I get "Exception; must be caught or declared to be thrown" when I try to compile my Java code? The rank of Jacobian matrix at a point of affine variety is independent of choice of generators Displaying layout marks in a document set with different layouts Is there any package that allows for the display of layout marks within a document where the layout changes several times throughout? I'm using the geometry facilities to issuing \newgeometry commands throughout my document, but it doesn't update the displayed layout and neither does the showframe package or the facilities of the memoir class.  EDIT: As Werner has pointed out, the showframe option of the geometry package displays correctly any updated page layout set by issuing \newgeometry commands.   My trouble came out of the fact that I'm issuing also \pagecolor commands and the page color seems to be hiding the layout lines typeset according to the geometry package. My confusion only worsened because the showframe package layout lines were not hidden by the page color (the package got the layout wrong on some pages, though). So, it all boils down to a conflict with the page color.   Even though I'm using geometry's showframe option for "debugging" ends, and I don't mind to have no page color at that stage of development, is it possible to override this problem and have at the same time both the page layout displayed by geometry as well as the page colored?   Btw, should I open a new question given that the problem is actually different from the originally posted one? Gambler's ruin and coin toss How do I check if an object has a specific property in JavaScript?  Consider:  x = {'key': 1}; if ( x.hasOwnProperty('key') ) {     //Do this }   Is that the best way to do it? As a developer of free software, I want to get my application into Ubuntu.  Should I provide a source tarball and ask for packaging? Or should I create a package myself? Should I target Ubuntu directly, or should I try to get into Debian and then into Ubuntu automatically? I have a question about my choice of name for publication.  I recently got married and legally changed my name to my husband's surname (for example's sake: from Hunter to Jones). So, despite legally being Ms Jones now, I would quite like to use the hyphenated name Hunter-Jones in the professional context and in publications. This is so that people realise that it is still me and so that I can somewhat keep my maiden name.  Is this possible or do I have to use my legal name professionally and when publishing? Thank you for any help What will happen if a plane trys to take off whilst on a treadmill? So, I thought I had a good understanding of this, but just ran a test (in response to a conversation where I disagreed with someone) and found that my understanding is flawed...  In as much detail as possible what exactly happens when I execute a file in my shell? What I mean is, if I type: ./somefile some arguments into my shell and press return (and somefile exists in the cwd, and I have read+execute permissions on somefile) then what happens under the hood?  I thought the answer was:   The shell make a syscall to exec, passing the path to somefile The kernel examines somefile and looks at  of the file to determine if it is a format the processor can handle If the magic number indicates that the file is in a format the processor can execute, then   a new process is created (with an entry in the process table) somefile is read/mapped to memory. A stack is created and execution jumps to the entry point of the code of somefile, with ARGV initialized to an array of the parameters (a char**, ["some","arguments"])  If the magic number is a  then exec() spawns a new process as above, but the executable used is the interpreter referenced by the shebang (e.g. /bin/bash or /bin/perl) and somefile is passed to STDIN If the file doesn't have a valid magic number, then an error like "invalid file (bad magic number): Exec format error" occurs   However someone told me that if the file is plain text, then the shell tries to execute the commands (as if I had typed bash somefile). I didn't believe this, but I just tried it, and it was correct. So I clearly have some misconceptions about what actually happens here, and would like to understand the mechanics.  What exactly happens when I execute a file in my shell? (in as much detail is reasonable...) Accented letters with IM FELL fonts How can I add text in a non-english language? How can I add text with non Latin characters? I'd like to get text in other languages like Arabic, Russin (Cyrilic), Japanese, Chinese, Malayalam among others, but I get rectangles instead of Arabic letters. I just noticed that I lost a bunch of points from my reputation score, and I used the "reputation" tab on my user profile page to try and track down the cause.  During my investigation, I noticed there was an unusual event of type "reversal". In the normal place of a question title, it says "voting corrected".     What does this mean, and what caused it?  Did I do something wrong? Why did I lose all of that reputation? Is the system punishing me for leaving too many good answers?  Is there any way to earn it back? I've got a rather large number of files on my Windows drive that have a colon in their name. (These came from unpacking some Unix archives.)   When I try to delete them, Windows (XP) complains that the file does not exist, and refuses to delete it. This happens when trying to delete or rename it from explorer or the command line. Still, chkdsk does not complain about those files nor fix the problem.   Any ideas on how to get rid of them? Use the beamer TOC style elsewhere