For certain packages to work properly, it seems to be necessary to enable the option --shell-escape, for example with pdflatex and auto-pst-pdf. I am informed that it enables external programs to interact with the engine, in the case of auto-pst-pdf a perl-script, and that this possibility is otherwise not enabled per default.  My question is: What are the dangers or known negative effects of setting this option as a standard?  (Two related questions could be: What is the exact reason this is set per default? Wouldn´t it be desirable to enable pdflatex to interact with external programs per default?)  The reason I am asking this is that I have know set --shell-escape as the standard in my editor. It is necessary for me to do this for certain documents, and I don`t want to bother thinking about it with every new document.
I stumbled upon an example, which needed to be compiled with the additional option --shell-escape. Using this option it worked just fine, but I'm curious:     Why or when is this option needed and what does it actually do?
How to Generate surface from points Hi Guys,  I have a set of points in 3D. How can I convert this into a surface ? Is an integer a sum of two rational squares iff it is a sum of two integer squares? Let $a\in \mathbb Z$. Is it true that $a$ is a sum of two squares of rational numbers if and only if it is a sum of two squares of integers?  I came to face this problem while dealing with quaternion algebras. I am struggling to convert .dwg to .shp, ideas? Any ideas as to how can I convert dwg to shp?  I tried Kosmo and gvSIG. gvSIG kind of worked but it seems like I lost information.. in addition everything was converted into lines, no polygons. I can manually recreate the polygons, but there must be a better program to do this conversion.  Ideas? I am trying to work through Hartshorne's book and while working through one of the exercises, I need to show the following:  Let $k$ be an algebraically closed field. Let $Y \subseteq A^3$ be the set $Y=\{(t,t^2,t^3)\;|\;t \in k\}$. Show that $Y$ is an affine variety.  The rest of the problem I have completed. I'm just not sure how to show that this set is closed and irreducible. I assume that they intend for $A^3$ to have the Zariski topology. Why isn't Jon executed on sight? So, to get spoilers out of the way -       Jon Snow is too honorable to break his oath and leave the Night's Watch.  However, he is stabbed a bunch, dies, and due to a line in the Night's Watch oath - "It shall not end until my death" - is able to leave without his usual reservation.   Now, this is fine from Jon's perspective.  However, there is a fairly rigid law about the Wall's deserters being punished by death. Which makes me wonder: why isn't Jon having more trouble with this?   He knows what happened, but others don't.  And the explanation that he actually did die doesn't seem like one the lands' lords and authorities would take on faith.  I know I wouldn't.  His story isn't quite like Sam's, who was sent by the Night's Watch to become a maester.  Jon is famous enough that many would know who he is, and that he has taken the black.  But a story like him dying and coming back to life is probably one that takes quite a but of time to stick - if it ever does.  A possible explanation might be that people know Jon is honorable and trust him. Or that they don't care about the law, and think that they can somehow benefit from not executing him - although the law seems to be a strict one, and not everyone seems to be psyched to help Jon out.  Or maybe by that time people coming back to life is a common enough thing that people believe it that easily.  Speculation aside, however, I am curious whether this was directly addressed from the higher-ups - the makers of the show, or the big boss himself.  Why isn't Jon executed on sight? Object-oriented shell for *nix Suppose that $f:\Bbb R\to \Bbb R$ is continuous and that $f(x)\to 0$ as $x\to \pm\infty$. Prove that $f$ is uniformly continuous.   Since $f(x)\to 0$ as $x\to \pm\infty$ we have $|f(x)|&lt;\epsilon $ whenever $x&lt;-K$ and $x&gt;K$ where $K&gt;0$.  Also $f$ is uniformly continuous on $[-K,K]$ as the domain is compact.  Hence $f$ is uniformly continuous in $(-\infty,-K)\cup [-K,K]\cup (K,\infty)$.  But how to conclude that $f$ is uniformly continuous on $\Bbb R$ from above as I may chose $x\in (-\infty,-K);y\in [-K,K]$ ,how to conclude that $|f(x)-f(y)|&lt;\epsilon $ from above for a given $\epsilon$?  Please suggest the edits required. Access a custom .NET DLL in VBScript I wrote a DLL in .NET and I want to access it in VBScript. I don't want to add it to the assembly directory.   Is there a way to point too the DLL and create an instance of it? How can I capitalize the first letter of each word in a string in Perl? When a person lifts a book while standing on the earth's surface. Why is his force considered external to the book-earth system? Isn't his force internal like the case of the forces that cause the exploson of a bomb. I think the forces the person exerts on both the book and the earth are internal since they are equal but opposite therefore resulting in the position of the centre of mass of the system being maintained and if i'm right is the mechanical energy of the system constant?  Am i wrong? Please correct me. There seems to be some bug where mac os is constantly contacting . You can prevent it by turning off the wifi, but then your computer is nothing more than a fancy calculator. Is there a program, vpn, or even the firewall option, to block this site from the whole os? Where do I get the key for the first house? Modify TikZ coil decoration Can I modify the existing tikz coil decoration, so that the downstrokes are not drawn in a certain interval, to produce a picture like this?    Edit: Previous attempts, code and MWE has been moved to or superseded by my own answer. How do I update my TeX distribution? I'm trying to compile a document that only works with an up-to-date distribution, so I'd like to know: how do I update my distribution? Please provide screenshots where appropriate.  List of answers           To keep an eye on what’s going on at CTAN you may subscribe to the  or the RSS feed feed://www.mail-archive.com/ctan-ann@dante.de/maillist.xml How can I tell if sheet a exists in a workbook? I have the following code that's not working as expected:  If Sheets("a") &lt;&gt; "" Then MsgBox ("sheet a exists")   How can I tell if sheet a exists in the workbook? I made my first sculpt model and I used a mirror modifier. But then I applied the mirror modifier, because I got a strange edge on the mirror line in sculpt mode. Now I modeled it, but it still mirrors the model, what in the beginning was good, but sometime I want to do asymmetrical things.  What did I wrong? Many thanks for your help!! Happy modeling :D Saving image from PHP URL When I'm not exploring fresh caves or lands in minecraft, I'm busy trying to find deposits of diamond, gold and iron deep in the earth. So far I've just been digging around just above bedrock on a whim to look for these rare minerals but I've started thinking that I should be taking a more controlled, efficient approach to mining.  What is the optimal mining strategy that yields the most rare minerals while minimizing blocks removed and time spent digging and traveling?  Edit: The existing answers are great for mining, but no one has addressed travel time to and from the mine which is usually ~60 blocks downward and incredibly tedious. Solutions? Test Class for a Custom Controller I know SO's policy is &quot;you don't have to register to ask questions,&quot; but there are so many new members and so many hit-and-runs... The majority of the questions I see now are coming from new users (i.e., it's their first question). Although unregistered users should still be able to ask questions, I think we should encourage users to create an account. Here is a couple of ways we could do that:  Explicitly encourage people to get an account: there's currently nothing telling people to do that. Maybe tell people something like &quot;Get an account, it's easy!&quot; and maybe show some of the perks of having an account (and having rep).  Maybe give a few bonus points for registering; and have that enable a basic privilege. It could be taken from one of the , for example.   Of course getting people to register is just half of the battle. I don't know what the stats are on this, but I think there's a number of users who create multiple accounts anyways. We could curb that by:  Having smart(er)? duplicate account detection systems, alerting someone who is about to create a new account and possibly has an account already. Give them a message like &quot;Hey, it looks like you already have  account, are you sure you want to create a new one?&quot;  Create a new privilege (10k? 20k?) that gives users tools to detect possible duplicate accounts, eg: &quot;List users with the same e-mail,&quot; &quot;List users with the same IP addresses,&quot;  etc. (without revealing said emails and IPs). Then the 10k/20k can look at other stuff (e.g.: posts) and refer the new user to a moderator for a possible merge.