sh -c 'echo hello ; echo world' Works fine on both host and remote machine, with the output of: hello world  but when I do ssh username@remote sh -c 'echo hello ; echo world', then the output is:  world  Why did the command eat my first echo hello command?
I have an odd error that I have been unable to find anything on this. I wanted to change the user comment with the following command.  $ sudo usermod -c "New Comment" user   This will work while logged onto a server but I want to automate it across 20+ servers. Usually I am able to use a list and loop through the servers and run a command but in this case I get a error.  $ for i in `cat servlist` ; do echo $i ; ssh $i sudo usermod -c "New Comment" user ; done  serv1 Usage: usermod [options] LOGIN  Options: lists usermod options  serv2 Usage: usermod [options] LOGIN  Options: lists usermod options . . .   When I run this loop it throws back an error like I am using the command incorrectly but it will run just fine on a single server.  Looking through the ssh man pages I did try -t and -t -t flags but those did not work.  I have successfully used perl -p -i -e within a similar loop to edit files.  Does anyone know a reason I am unable to loop this?
Is the Echo of a Echo Knight actually a creature? I've always been certain that the echo created by an Echo Knight fighter using their 3rd-level feature Manifest Echo is not defined in game terms as a creature, since the description of the echo never explicitly tells it is a creature. But the presence of people believing the echo to be a creature in lieu of the fact that it is immune to all conditions and might make saving throws (game characteristics typically associated with creatures only) brought this doubt to my mind.  from Jeremy Crawford implies it is just an image and not a creature, further confirming that the feature should tell you, but  implies that the echo is an object whilst the feature doesn't explicitly say so. (Included for reference and insight, since tweets are not eligible as official ruling) Is the echo a creature? Start + Gerund vs Start + Infinitive: is there a subtle tense difference? Is there a subtle difference between these fragments:  Jack walked over to the car, opened the door, and started to look for the aspirin vial in the glove compartment. Jill looked on skeptically. Jack walked over to the car, opened the door, and started looking for  the aspirin vial in the glove compartment. Jill looked on skeptically. Installing Numpy on 64bit Windows 7 with Python 2.7.3 Consider:  List&lt;String&gt; someList = new ArrayList&lt;String&gt;(); // add "monkey", "donkey", "skeleton key" to someList     for (String item : someList) {     System.out.println(item); }   What would the equivalent for loop look like without using the for each syntax? How to run GUI applications remotely on a headless server? I'm new to Ubuntu - sorry for novice questions. What I have - is Ubuntu server, to which I have access only via ftp and putty. What I would like to do - is to run firefox (or any other browser) from that Ubuntu machine.  I've managed to install firefox , but when I'm trying to run something like this:  x-www-browser http://google.com   It is saying:  Error: no display specified   I don't understand - there is no display at all at Ubuntu sever - it is just computer case on rack, the only display I have - is mine.  Don't know, how to redirect this display output to my machine (if this is possible at all). Name tikz pic as if it was a node I'm confused about tikz pics. I can freely define them without issue, and even add coordinates inside that will be available by name inheritance like (-A) as for example in \pic (S) at (0,0) {myPic}; \draw (S-A) -- ++(0,0);. This is all documented around p. 255 of the pgf manual.  However I don' understand why it is not possible to give a name to a pic like the one above if no coordinate is defined inside it. By default it would be great if it could behave like a normal node.  MWE:  \documentclass{minimal} \usepackage{tikz}  \tikzset{     myBlock/.pic = {         \node[draw,minimum width=1cm,minimum height=0.5cm] at (0,0) {};     },     myBlockNamed/.pic = {         \node[draw,minimum height=1cm,minimum width=0.5cm] (-m) at (0,0) {};     }, }  \begin{document} \begin{tikzpicture}     \pic () at (0,0) {myBock}; % can't give it a name     \pic (S) at (3,0) {myBlockNamed}; % can give it a name     \draw (S-A) -- ++(2,0); \end{tikzpicture} \end{document}   The underlying point is I'm working on a control blocs library (so that we can stop the chat below with @Alenanno). For example here is the definition of a math operator  \tikzset{     mySum background/.style = {         circle, minimum size=1.5em, fill=white,     },     mySum edge/.style = {         draw=black, circle, minimum size=1.5em, line width=.5pt,     },     pics/bOp/.style = {     code = {       \node [mySum background] {};       \foreach \t [count=\i] in {#1}{         \pgfmathsetmacro{\angle}{\i*90}         \node[anchor=center, font=\tiny] at (\angle:0.45em) {$\t$};       }       \node [mySum edge] {};     },   }, } Please help me  to evaluate combinatorially the following sum: $$\sum_{k=0}^n \binom{n}{k}$$   Thank you. A sine integral $\int_0^{\infty} \left(\frac{\sin x }{x }\right)^n\,\mathrm{d}x$ The following question comes from   post $$\int_0^{\infty} \left(\frac{\sin x }{x }\right)^n\,\mathrm{d}x$$ but now I'd be curious to know how to deal with it by methods of complex analysis. Some suggestions, hints? Thanks!!!  Sis. It is currently said that MD5 is partially unsafe. Taking this into consideration, I'd like to know which mechanism to use for password protection.  This question,   suggests that hashing multiple times may be a good idea, whereas  suggests using salt.  I'm using PHP. I want a safe and fast password encryption system. Hashing a password a million times may be safer, but also slower. How to achieve a good balance between speed and safety? Also, I'd prefer the result to have a constant number of characters.   The hashing mechanism must be available in PHP It must be safe It can use salt (in this case, are all salts equally good? Is there any way to generate good salts?)   Also, should I store two fields in the database (one using MD5 and another one using SHA, for example)? Would it make it safer or unsafer?  In case I wasn't clear enough, I want to know which hashing function(s) to use and how to pick a good salt in order to have a safe and fast password protection mechanism.  Related questions that don't quite cover my question: Solve this integral for free WiFi I saw this today, I checked in Mathematica and the integral comes out to $\pi$, but I have no idea how to solve it.     FREE Wi-Fi: The Wi-Fi password is the first $10$ digits of the answer.   $$\int_{-2}^2\left(x^3\cos\frac x2+\frac12\right)\sqrt{4-x^2}\ dx$$ Factorial Inequality problem $\left(\frac n2\right)^n > n! > \left(\frac n3\right)^n$ I met an inequality, I ask, do not mathematical induction to prove that:     Prove \[ \left(\frac n2\right)^n > n! > \left(\frac n3\right)^n \] without using induction Why XML-Serializable class need a parameterless constructor I'm writing code to do Xml serialization. With below function.  public static string SerializeToXml(object obj) {     XmlSerializer serializer = new XmlSerializer(obj.GetType());     using (StringWriter writer = new StringWriter())     {         serializer.Serialize(writer, obj);         return writer.ToString();     } }   If the argument is a instance of class without parameterless constructor, it will throw a exception.     Unhandled Exception:   System.InvalidOperationException:   CSharpConsole.Foo cannot be serialized   because it does not have a   parameterless constructor.    at   System.Xml.Serialization.TypeDesc.CheckSupported()   at   System.Xml.Serialization.TypeScope.GetTypeDesc(Type   type, MemberInfo sourc e, Boolean   directReference, Boolean throwOnError)   at   System.Xml.Serialization.ModelScope.GetTypeModel(Type   type, Boolean direct Reference)    at   System.Xml.Serialization.XmlReflectionImporter.ImportTypeMapping(Type   type , XmlRootAttribute root, String   defaultNamespace)    at   System.Xml.Serialization.XmlSerializer..ctor(Type   type, String defaultName space)    at   System.Xml.Serialization.XmlSerializer..ctor(Type   type)   Why must there be a parameterless constructor in order to allow xml serialization to succeed?  EDIT: thanks for cfeduke's answer. The parameterless constructor can be private or internal. How to evaluate this trigonometric limit? I have been struggling to solve this limit.  What is the limit as $x$ approaches $45^0$ of $$\frac{\sqrt{2}\cos x-1}{\cot x-1}?$$   I know how to use L'Hospital's rule to calculate this limit and got the answer as $0.5$. But, how do I calculate the limit by manipulating the function? Please provide only some hints to proceed. Do electrons have shape? Using separation of variables to solve the wave equation Flying with a desktop computer (as checked luggage) On an upcoming trip, I will be taking a desktop computer and monitor as checked luggage (on a United/Continental flight). What should I be aware of when doing this? What needs to be done to properly protect all the components? Are there any airline policies I should be aware of? Is it possible to understand the One Piece storyline by watching the movies only? I am trying to run a function from  in ArcMap 10.1; Sink evaluation. But before it can finish it returns an error message, that, frankly, I don't understand at all.  It goes System.runtime.interopservices.comexception (0x80004005): error hresult e_fail .  Can anyone help me solve this? I have tried all I can think of. Run the function from the toolbox instead of dropdown menus, shorten paths, restart ArcMap, reinstall AHT, open new map documents, restart my computer, wait till next day and see if it automagically have fixed itself...   After searching this forum I found a , although it's got no answers. Now I'm all out of ideas, can anyone please help me?!    I'm using ArcMap 10.1 SP1 basic license and Windows 7.    I think I have narrowed it down a bit, still not clear what's wrong though. Sink evaluation uses a series of functions in Arcmap, of which one is Zonal statistics as table. That's the one it gets stuck on. The input raster somehow does not exist, path unknown. I guess this is some intermediary raster.       After consulting the Arc Hydro team, I got the advice not to use grids stored in a gdb (which I didn't). I have also tried to change target locations, thanks to @G.Oxsen. Unfortunately neither of those solved the issue. According to the Arc Hydro team, GPL0 that I asked about earlier is an in-memory grid, so probably no problem there.   I am currently pursuing that it is related to the installation of SP1. Anyone out there using AHT with SP1 and got Sink evaluation working?    Uninstalling SP1 did not change anything, unfortunately. Still working on this, but with less intensity. Seems like I'll have to find workarounds...    By reducing the number of sinks in need of processing I managed to get Sink evaluation running. Having the files not stored in a gdb seem to help as well, as mentioned earlier, and using integer grids.  Changing the "Maximum number of unique values to render" in ArcMap Options (Customize menu), tab Raster --> Raster dataset is another tip that I got (from the Arc Hydro Team). Restarting ArcMap after running every one or two functions also helps keeping things stable. What screenshot tools are available? I have noticed that many people use images in their Ask Ubuntu answers. What software are people using? Why didn't Spock die in The Search for Spock?