Unable to exit from an existing branch
Git for beginners: The definitive practical guide
Foreign key constraint on array member? Why is the direct product of a finite number of nilpotent groups nilpotent? A coin is tossed three times: The probability of zero heads is 1/8 and the probability of zero tails is 1/8.  And my question is: What is the probability that all three tosses result in the same outcome?   So, if P(zero heads)= 1/8 , then that should be the same of p(all tails)?  If so, we could use the Addition Rule which is $P(A \cup B) = P(A) + P(B)$  where A and B are disjoint events, i.e. $A \cap B = \emptyset$, A is the event of tossing all heads and B is the event of tossing all tails.  I'm not sure how to continue after that... would the complement be used? How to cd into a directory with this name "-2" (starting with the hyphen)? I have a directory named:  -2   I want to cd into it but the cd complains:  bash: cd: -2: invalid option   With no success, I've tried:  cd "-2" cd '-2' cd \-2   Any solution?  Edit: no file browsers like mc, etc. available on the server. How does the basic RS Flip-Flop (also known as latch) works? I am sure there is something wrong i am doing but i just want someone to point it to me.  Why can't we say that $e^{\frac {\pi i}{3}} = \left(e^{\pi i}\right)^{\frac {1}{3}} = (-1)^{\frac {1}{3}} = -1$ Why do we have to calculate it by the formula as it is (which produces different value)  Another question is why can't we say that $ (-1)^{\frac {1}{2}} = \left(\left (-1\right)^{2}\right)^{\frac {1}{4}} = 1^{\frac {1}{4}} = 1$  Again i have to say that i know this is all wrong i just want to know why it is wrong How to draw simple table Within a custom command, I'm doing the following to write to a file:  \newcommand\mycommand[1]{   \newwrite\file   \immediate\openout\file=foobar.tex   \immediate\write\file{     foo     bar     #1     blarg   }   \immediate\closeout\file }   Of course when I invoke it as \mycommand{baz}, I get the following contents in foobar.tex:  foo bar baz blarg   with all new lines turned into spaces by LaTeX. My question is, is there a way to output these lines into the file "as expected", i.e. with real new lines at the end of each line instead of a space? I'm thinking some \catcode wizardry should do the trick, but I'm not sure which character I need to redefine and to what category code.  Update  The solution in  works perfectly. The only problem is when #1 contains embedded newlines. I can of course send it to mycommand with its own slew of ^^J, I was wondering if there is a way to avoid this. How do I add more categories to Mac OS X Finder's sidebar? My Finder sidebar has two categories: Favorites and Devices. How do I add more categories? Are the known exoplanets representative of the population of exoplanets? An  states that most of the 715 newly announced exoplanets orbit very close to their host stars.   Do the theories predict that this is a representative sample and that most planets are very close to their host stars? Or is it just that our current detection techniques are predisposed to finding only those planets close to their stars (because the sensors look for dimming of the host star for example)? Given a pointed category $X$, is $|N(X)|$ contractible ($N(X)$ is the nerve of $X$)? Or are there counter-examples? Just wondering, I'm about to buy it and it sounds awesome, but how many characters can I have in Skyrim on the PS3? Am I limited to just 1, or can I make more than one character at once? Comparing $2^n$ to $n!$ MonoTouch.Dialog: How to set limit of number of characters for EntryElement Let $x_{1},x_{2},\cdots,x_{n}$ be real numbers. Show that     $$\sum_{i,j=1}^{n}|x_{i}+x_{j}|\ge n\sum_{i=1}^{n}|x_{i}|.$$   I think this problem may be solved using nice methods, but I can't find them yet; I know this may be of use: $$|a|+|b|\ge |a+b|.$$ But I can't make it work. Thank you everyone. Units and Nilpotents If $ua = au$, where $u$ is a unit and $a$ is a nilpotent, show that $u+a$ is a unit.   I've been working on this problem for an hour that I tried to construct an element $x \in R$ such that $x(u+a) = 1 = (u+a)x$. After tried several elements and manipulated $ua = au$, I still couldn't find any clue. Can anybody give me a hint? How to confirm that mail has been delivered or not? What is the best way to randomize an array of strings with .NET? My array contains about 500 strings and I'd like to create a new Array with the same strings but in a random order.  Please include a C# example in your answer. Ctrl -C, Ctrl -V not working in different keyboard layout When I am in English, Ctrl+C, Ctrl+V works fine when I need to copy paste. But when I turn to Greek, Ctrl+C and Ctrl+V and basically no shortcut almost works in Greek.  So each time I have to alt shift and go back to English in order to user Ctrl+C to copy something. How can I apply this to the Greek keyboard profile?  EDIT  I also realized that when using NetBeans IDE 7.4,  I can copy and paste in Greek but I can't use the tonic system of the language over the words. In Aptana studio I can't use Copy and paste Ctrl+C, Ctrl+V When using gedit everything works fine. Different software use different keyboard layout settings? Find three real orthogonal matrices of order $3$ having all integer entries.   I have no idea to solve the problem. I don't know how to start. If $A$ be such matrix then $AA^T=A^TA=I_3$. Please help me.