Finding a file starting with '-' dash
How do I delete a file whose name begins with "-" (hyphen a.k.a. dash or minus)?
Series about being that could change sex and age - "The Morph*" I'm trying to remember information about a series of three books I read in the early 1980's (first book could have been published in the 1970's). The book featured a character who was a scientific creation of some sort. It was (initially, I believe) an assassin, and had the ultimate getaway scheme; with effort, it could change its body, becoming about 10 years younger and switching sex. It changed 4 or 5 times in the first book, coming down from a senior citizen to someone in their teens or twenties; in the second and third books, it changed once per book (by the last book, it was a child or a young teenager).  The first book was title something like "The Morph..." where whatever the word was that started with "Morph" was this creature. No recollection of the author's name, or the titles of the other two books.  I think the cover of the first book was predominantly yellow, with black silhouettes representing the character at the four ages seen in the book, and a black title. And/or, the book might have been published by DAW (all their books at the time had yellow spines with black letters). $H$ is normal subgroup of $G$ iff $gHg^{-1}=H$ for every $g$ of $G$ Given the following definition of normal subgroup     A subgroup $H$ of a group $G$ is said to be normal if, for every $g\in G$: $$gH=Hg$$   I've tried to show that $H\mathrel{\unlhd} G$ if and only if we have $gHg^{-1}=H$ for every $g\in G$:  (if) Let $H\mathrel{\unlhd} G$, $g\in G$; if $l\in gHg^{-1}$, there exists $h\in H$ such that $l=ghg^{-1}$ and since $gh$ = $h'g$ for some $h'\in H$, then $l=ghg^{-1}=h'(gg^{-1}) = h'\in H$. Let $h\in H$; we can write $h$ as $hgg^{-1}$, and since $hg = gh'$ for some $h'\in H$, we obtain $h = hgg^{-1} = gh'g^{-1}\in ghg^{-1}$. So $gHg^{-1}=H$.  (only if) Let $gHg^{-1}=H$, $g\in G$; if we take an $l\in Hg$, $l = hg$ for some $h\in H$, we note immediately that $l=hg=(gh'g^{-1})g=gh'\in gH$. What should I do to show that $gH\subset Hg$?  I'm also wondering if this mess is correct, and if it is possible a more elegant proof of this fact. What is the most elegant proof of the Pythagorean theorem? The  is one of the most popular to prove by mathematicians, and there are  (including one from ).    What's the most elegant proof?  My favorite is this graphical one:    According to cut-the-knot:     Loomis (pp. 49-50) mentions that the   proof "was devised by Maurice Laisnez,   a high school boy, in the   Junior-Senior High School of South   Bend, Ind., and sent to me, May 16,   1939, by his class teacher, Wilson   Thornton."      The proof has been published by Rufus   Isaac in Mathematics Magazine, Vol. 48   (1975), p. 198. $\lfloor x\rfloor + \lfloor y\rfloor \leq \lfloor x+y\rfloor$ for every pair of numbers of $x$ and $y$ Give a convincing argument that $\lfloor x\rfloor + \lfloor y\rfloor \leq \lfloor x+y\rfloor$ for every pair of numbers $x$ and $y$. Could someone please explain how to prove this? I attempted to say that the largest values that could be added to $x$ and $y$ is $0.99$ and that doing so still made $\lfloor x\rfloor + \lfloor y\rfloor &lt; \lfloor x+y\rfloor$. However, my answer was not accepted. How many constructor arguments is too many? Let's say you have a class called Customer, which contains the following fields:   UserName Email First Name Last Name   Let's also say that according to your business logic, all Customer objects must have these four properties defined.  Now, we can do this pretty easily by forcing the constructor to specify each of these properties.  But it's pretty easy to see how this can spiral out of control when you are forced to add more required fields to the Customer object.    I've seen classes that take in 20+ arguments into their constructor and it's just a pain to use them.  But, alternatively, if you don't require these fields you run into the risk of having undefined information, or worse, object referencing errors if you rely on the calling code to specify these properties.  Are there any alternatives to this or do you you just have to decide whether X amount of constructor arguments is too many for you to live with? Open local folder from link PhD in Europe without scholarship from non-European homeland I earned my bachelors in Computer Engineering from my home country. I am now enrolled in a Physics masters program in the same university. Next year I plan to find a different university in Europe in which to enroll in a Computer Engineering PhD program.  However I doubt that I'll receive any scholarships from my homeland's government when studying abroad. Can I survive if I start to live out of my own my pocket? Is that enough to live in Europe just for a half year. Are there any available funds that can supplement my income such as a TA/RA's salary?  My main question is:   How to survive if I want to study PhD in Europe without any scholarship from my home country? Which country might provide sufficient support for a foreigner to study at graduate level?   I am interested to Germany and Finland but any European country would be acceptable! So we have something like:  \documentclass{article} \setcounter{secnumdepth}{2} \setcounter{tocdepth}{2} \usepackage{amsmath}  \begin{document}  \tableofcontents  \section{Brushless Motor Fundamentals} \subsection{Brushless Motor Operation} \subsubsection{DC Motor Operation} Torque is generated in DC motors from the magnetic force, also known as the Lorentz force, which is produced when an electric current is passed through a coil in a magnetic field. This force is given by $F=q[E+(v\times B)]$, where $F$ is the force perpendicular to the coil, $E$ is the electric field in the coil, $B$ is the magnetic field, and $v$ is the velocity of the charged particles in the coil. From mechanics, torque is $\tau=F\times r$.  \section{Brushless Motor Fundamentals 2} \subsection{Brushless Motor Operation} \subsubsection{DC Motor Operation 2} If the electrical force is ignored and the remaining magnetic force is used, with the assumption that $v$ is perpendicular to $B$, we find that $\tau=qvBrsin\theta$.  \end{document}   How to show subsubsections and paragraphs in TOC? What does "isomorphic" mean in linear algebra? What does the `who` command result `root :0` mean? The return value of command who will always include root :0 in X Window pts. I guess it actually means the GNOME login. Am I right?  Another question is where to get this knowledge, as I don't see it in the man who, neither in info who.  Example  [root@localhost root]# who root     :0           Sep 11 06:33  root     pts/0        Sep 11 06:36     (:0.0) $\infty = -1 $ paradox I puzzled two high school Pre-calc math teachers today with a little proof (maybe not) I found a couple years ago that infinity is equal to -1:   Let x equal the geometric series: $1 + 2 + 4 + 8 + 16 \ldots$  $x = 1 + 2 + 4 + 8 + 16 \ldots$ Multiply each side by 2:  $2x = 2 + 4 + 8 + 16 + 32 \ldots$ Again from the equation in step 1, move the $1$ term to the left hand of the equation:  $x - 1 = 2 + 4 + 8 + 16 + 32 \ldots$ So the following appears to be true:  $2x = x - 1 \implies x = -1$   This is obviously illogical. The teachers told me the problem has to do with adding the two infinite geometric series, but they weren't positive. I'm currently in Pre-calc, so I have extremely little knowledge on calculus, but a little help with this paradox would be appreciated. When to use "have" and "have got" Unfortunately hard disk of my system is damaged, now I recovered my database. But it cannot be attached again to SQL management studio 2005. The error is:  myfile.mdf is not a primary database file. (SQL server , error 5171) I registered my Stack Overflow account using the Stack Exchange OpenID provider. I later changed my e-mail, but I cannot change the e-mail address associated with my OpenID for some reason. Why is that, and how do I change it? I logged in to Stack Exchange and it lets me change my password, but never my e-mail. iOS app blocking actions with "you must join this site" message for sites I belong to See these sentences:     See there, it seems that someone is inside the house. OVER   See there, it seems that someone is in the house.   Another example:     The doctors found two bullets in his body. OVER   The doctors found two bullets inside his body.   Certainly, both are interchangeable, aren't they? But in the bullet's example, the second one looks natural. I'm not sure why. Is it something that bullets were first out and then they went inside? But if that's the case, someone is in the house is also okay. That person too was out first! In a complex vector space, $\langle Tx,x \rangle=0 \implies T = 0$ "It is not possible to check out a single file. The finest level of checkouts you can do is at the directory level."  How do I get around this issue when using Subversion?  We have this folder in Subversion where we keep all our images. I just want to check out one file (image) from that. This folder is really big and has ton of other stuff which I don't need now. Custom command does not reference a label created with a previous custom command How to check if a string contains a substring in Bash