If someone from Russia is leaving to visit the US, do they need plane tickets before they get a visa?
My online friend is asking for money in order to visit my home country. Is this a legit request or a scam?
I am doing some challenges. This is one them. I am trying to brute-force 4 digit pin with the password to get my desired answer. After connecting to the port It prompts me to enter the password then space then 4 digit pin. I tried to brute-force the pin using the script:  #!/bin/bash   nc localhost 30002   sleep 2    for i in {0000..9999};       if [[ $(echo 'UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $i' &lt;/dev/stdin) = ^Wrong*]];                         then          continue       echo '[+] Pincode Cracked! Pincode = $i'       fi   done  but it seems that this doesn't input the pass and pin to stdin, before i tried doing something like this -&gt; if [[ $(echo 'UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $i') = ^Wrong* ]]; What am I doing wrong here? UPDATE: Okay, so after researching around. I wrote this: for i in {0000..9999} do     if [ (echo &quot;UoMYTrfrBFHyQXmg6gzctqAwOmw1IohZ $i&quot; | nc localhost 30002 | grep -o Wrong) == &quot;Wrong&quot; ]    then       sleep 0.1       continue    fi    echo &quot;- - - - - - - - - - - - - - - - - - - - - - - - [$i]&quot; done  This might even work but as you can see it opens new connections in the loop which makes it really slow and exhaust the system. Can a character use the Misty Step spell to escape from the Iron Bands of Bilarro? Can a character escape the  (DMG p. 177, listed in the SRD as the ) with the  spell? To clarify, I am not asking if the bands prevent teleportation. I am asking whether the bands are teleported with the character as he teleports using misty step. An explanation of Hawking Radiation I want to disable the internal Microphone on my laptop and the internal Webcam completely that they're no longer selectable, and no longer available?  I will only use my external Webcam, and my external (USB) headset.  The internal audio should still be available for playback. How will multiple GPUs improve Cycles' rendering performance? I have an NVIDIA Titan GPU and I'm able to add another card, but I wonder whether  Blender will benefit from more than one GPUs?  Should I do it as SLI or should I just do it as an added card? I just need some help in understanding how Blender will use either SLI or a second GPU.  Note that I only use Cycles. Movie: Creature crawls out of its current hosts mouth into next hosts mouth How can I require an optional Perl module if installed? I have Perl code which relies on Term::ReadKey to get the terminal width. My installation is missing this module, so I want to provide a default if the module isn't present rather than throw an exception. How can I conditionally use an optional module, without knowing ahead of time whether it is available. # but only if the module is installed and exists use Term::ReadKey; ...  How can I accomplish this? How does entropy depend on location and scale? The entropy of a continuous distribution with density function $f$ is defined to be the negative of the expectation of $\log(f),$ and therefore equals  $$H_f = -\int_{-\infty}^{\infty} \log(f(x)) f(x)\mathrm{d}x.$$  We also say that any random variable $X$ whose distribution has density $f$ has entropy $H_f.$  (This integral is well-defined even when $f$ has zeros, because $\log(f(x))f(x)$ can be taken to equal zero at such values.)  When $X$ and $Y$ are random variables for which $Y = X+\mu$ ($\mu$ is a constant), $Y$ is said to be a version of $X$ shifted by $\mu.$  Similarly, when $Y = X\sigma$ ($\sigma$ is a positive constant), $Y$ is said to be a version of $X$ scaled by $\sigma.$ Combining a scale with a shift gives $Y=X\sigma + \mu.$  These relations occur frequently.  For instance, changing the units of measurement of $X$ shifts and scales it.  How is the entropy of $Y = X\sigma + \mu$ related to that of $X?$ In electromagnetism, why does nature prefer the right-hand rule over the left-hand rule? How can brackets be escaped in using string.Format? For example: String val = &quot;1,2,3&quot; String.Format(&quot; foo {{0}}&quot;, val);  This example doesn't throw an exception, but it outputs the string foo {0}. Is there a way to escape the brackets? How do I find out which DOM element has the focus? I would like to find out, in JavaScript, which element currently has focus. I've been looking through the DOM and haven't found what I need, yet. Is there a way to do this, and how?  The reason I was looking for this:  I'm trying to make keys like the arrows and enter navigate through a table of input elements. Tab works now, but enter, and arrows do not by default it seems. I've got the key handling part set up but now I need to figure out how to move the focus over in the event handling functions. What exactly do quotation marks around the table name do? I thought that the quotation mark (") was simply a type of grouping marker but I'm debugging some NHibernate code and notice that while  SELECT * FROM site WHERE site_id = 3;   Works fine  SELECT * FROM "site" WHERE site_id = 3;   fails with a table or view does not exist error.  What gives? I have a configuration file where a developer can specify a text color by passing in a string:   &lt;text value="Hello, World" color="Red"/&gt;   Rather than have a gigantic switch statement look for all of the possible colors, it'd be nice to just use the properties in the class System.Drawing.Brushes instead so internally I can say something like:   Brush color = Brushes.Black;   // Default   // later on...  this.color = (Brush)Enum.Parse(typeof(Brush), prasedValue("color"));   Except that the values in Brush/Brushes aren't enums.  So Enum.Parse gives me no joy.  Suggestions? checking if a number is a prime I was reading Wikipedia, and it was given that "all primes are of the form 6k ± 1"  (other than 2 and 3), where k = 1,2,3,4,...  Is this statement correct? If yes, can we use this to test if a given number is a prime number? For instance, we can say that 41 is a prime number, since there exists an integer K (K >= 1), such that 6k - 1 = 41 ==> k = 7.  I am confused why this test cannot be used to test if a number is prime?  Thanks, Sekhar Remove Background in Inkscape LaTeX figures side by side I want to place 2 images side by side in LaTeX. I have 2 .png files and I don't understand how to do it in LaTeX. I have tried many ways but could not get a good result. Why does the kinetic energy of a particle moving in circular motion increase when the turn radius decreases and no torque is acting? Why does the kinetic energy of a particle moving in circular motion increase when the turn radius decreases and there is no torque acting? E.g. if a planet is rotating about its axis and it shrinks to half of its radius then according to conservation of angular momentum velocity will doubled, i.e. its kinetic energy will increase. Does this mean that without any external force the kinetic energy of any thing can be increased? Please explain! Reading a bit about recent Monica Cellio related posts, I am afraid that I may be using a language that is a lot like English, but might not be the Stack-Exchange-approved version of English. For example, my English has had a certain gender-neutral pronoun in living use for centuries. That pronoun is used throughout the literature written in this version of English. It is used in the English I was taught as a grammar school student and later as a graduate student working on a master's thesis. I believe that this English is good enough to communicate about topics relevant to the various Stack Exchange sites.  The last thing I want from Stack Exchange is to be booted out because I slip up and accidentally use the language that has served me so well for a lifetime.  The topics discussed on Stack Overflow (I almost referred to it as a "sister site;" would that have been allowed? "mother site?" Good thing I didn't?) are often centered on languages which have formal descriptions.  Where is the formal description of the language that is to be used on Stack Exchange?     Strive not with a man without cause, if he have done thee no harm.      He shall die without instruction; and in the greatness of his folly he shall go astray. How does printf with multiple arguments separated by space work I have the following printf function:  $ printf '%s %s %s\t%s\n' 100644 blob 8e1e f1.txt 100644 blob 9de7 f2.txt | git mktree   Can anyone please explain what it produces and why? I expected to have equal number of formatting options %s for each argument string but I have a lot more arguments strings here. Change the default size of square brackets in latex math mode Personally I think the default size of square brackets in latex math mode is too small. For example, for an interval [a,b], I would prefer \big[\big] as opposed to plain []. My question is, what can I do to change the default size of [], so that when I input [] in math mode, they will show up automatically the same size as \big[\big]?  Right now I'm defining a new command called \b{} which takes one argument and inserts it between \big[ and \big], but the code looks ugly. Apparently \newcommand (or \def or \let) does not allow [ to be refined.  Any help is much appreciated. Thanks.