Sorry, this is a bit of a noob question, but...  I am creating a login page and I am having difficulty getting the login page to send me back to the web page that prompted the login redirect...  Can the previous page be stored via POST variable and accessed on the next page (login.php)?...I am having trouble just keeping that webpage url...if someone could show me how and explain why that would be amazing!  If I could just see how it looks to store variables to post so they can be viewed on the next page that would solve all my problems  original webpage:  &lt;?php     //how do I post current url so it can be accessed on login     require_once('./../User_Auth/includes/authenticate.php'); ?&gt;  login webpage:  `header("Location:");`
I want to get user input in one page, store that in a php variable and use it in another php page. I have tried using 'sessions' but it doesn't seem to be working. Is there another safe alternative? This information is likely to be usernames and passwords.
When should I add another answer? I have been member of SO for 4 months. I have a question regarding some functionality. Whenever I give an answer to a question, there is functionality given Add Another Answer. I can comment on my answer at any time and also able to edit answer. Then   Why this functionality given on SO to add another answer?  When should I add another answer?  Why there is requirement of multiple answers? What is limit of adding answers to single question? Why won't OS X trust GitHub's SSL certificate? Standard error of regression coefficient without raw data Can I clear an area of my prison for everyone BUT max security prisoners? `sudo echo "bla" >> /etc/sysctl.conf` permission denied Disclaimer: I'm pretty novice at sysadmin stuff.  I'm trying to set up port forwarding in an AWS EC2 instance, this has to be done in the command-line because I don't want to go in and edit anything, it has to be automatic (it's part of a build process).   sudo echo "net.ipv4.ip_forward = 1" &gt;&gt; /etc/sysctl.conf      Permission denied   The weird thing is I've been (successfully) using sudo for pretty much every command that required su privileges. If I do sudo su before the command (trying it out by hand in an ssh session), then it works.  Reasons behind this? Possible solutions that don't involve sudo su or manual edits? How can I retrieve mp3 metadata in Python? Poincaré inequality for a subspace of $H^1(\Omega)$ The following is the well known  for $H_0^1(\Omega)$:       Suppose that $\Omega$ is an open set in $\mathbb{R}^n$ that is bounded. Then there is a constant $C$ such that   $$ \int_\Omega u^2\ dx\leq C\int_\Omega|Du|^2\ dx\quad \textrm{ for all   }\ \ \color{red}{u\in H_0^1(\Omega)}. $$   Here is my questions:    Can the condition $u\in H_0^1(\Omega)$ be relaxed so that the inequality is still true? More precisely, suppose $H$ is a subspace of $H^1(\Omega)$ such that for any $u\in H$, $u|_\Gamma=0$, where $\Gamma$ is a ([Added:]nonempty) closed proper subset of the boundary $\partial\Omega$ and the idenity is in the sense of trace. In other words, $u$ is only zero on a part of the boundary. Do we still have the Poincaré ineqaulity in $H$?    [Added:] This question is motivated by the following exercise Does an Evocation shield have a reactive utility to it? Cancel misclicked flags YA coming-of-age fantasy series, protagonist keeps pigs I lost a series books during a move and I'm thinking I might like to get them for my son.  They are about a teenage orphan who lives with a (sort of) wizard who's primarily known for his prize pig. There is a "bad guy" but he doesn't do much - he starts off the action in one by scaring the pig, and the boy has to chase after it. He goes on several such adventures, notably one to "find his true nature" that ends with him staring into a pool.  I suppose it could be the early books of , but I'm pretty sure I read them in the 1980s, not 90s, and title seems wrong. And unlike the Wiki description, in the series I'm thinking of, there's no real magic to speak of - its "out there" but does not seem to be part of the action that I recall. PHP/MYSQL login error? ... namely that if $n &gt; 1$ and $(n − 1)!\equiv−1\pmod{n}$, then $n$ is prime.  This is for a number theory class I'm in at Penn State. My idea is to follow accordingly, but I can't get it concretely..  Reason by contradiction, suppose that $n$ is not prime.   Then $n = ab$, where $1 &lt; a, b &lt; n$  In particular $(n-1)! = ai$ for some $i\in\Bbb{Z}$. $\\$ If $(n-1)! = nj - 1$ for some $j\in\Bbb{Z}$ then it follows that a probably doesn't divide $-1$? I am trying to change the page size in the QGIS 3.0 Composer but I am not able to see the Composition tab.  I have right clicked an empty space in the toolbar but did not see anything about composition.  I am using Windows 7.  I tried looking at the QGIS docs but they are still in testing. I've seen the  here before, as well as on many sites on the web.  I've also seen different info on what was covered.  I'm not a huge X-Men fan, but I do enjoy the characters and stories, so I know I'm probably missing out on a lot, and may have missed the obvious along the way because I didn't read a particular series or something like that.  I had a relative die from leukemia a few years ago and that reminded me of basic junior high science: that red and white blood cells are produced in the bone marrow and must be able to reach from the marrow into the blood vessels.  The leukemia my relative had was the kind where the "bad" cells would surround the marrow and prevent the new "good" blood cells from getting out to the rest of the body.  So just how much of Wolverine's skeleton is covered with Adamantium?  If it's the whole thing, there'd have to be openings for new red blood cells to get out if he is to remain alive.  I've never seen a reference to this issue, is it ever addressed?  That also raises another issue along the same line: Are hard to reach areas, such as ball and socket joints covered?  If not, then stress on other covered areas could be transferred to the weaker uncovered areas, which would lead to breakage there.  And if joints like that are covered, is there anything to say how it was done?  Are there openings or gaps in the Adamantium covering on his body?  Are there any references to any of these issues that deal with them? Which email was the verification email sent to? I started my app today and it said that I needed to verify my email. But I don't know the email I chose. I logged on every email in but there was never a verify email. Is there a way to know your email on Pokemon Go? Can there be a notification for those people that participated in the question in the past (either who asked or answered it) once a bounty is started on it? I'm working through Exercise 40 from section 1.2.3 of Knuth's The Art of Computer Programming volume 1, but am finding myself unable to produce a rigorous proof, and the one  is suspect and not quite clear enough (for me, at least) in some of the steps; in particular, how to "[identify] the $k$th order coefficient in [the] two polynomials."  The problem is this: given a Vandermonde matrix $[x_j^i]_n$, show that the inverse is given by  $$ [b_{ij}]_n = \left[ \frac{    \sum_{\substack{1 \leq k_1 &lt; \dotsc &lt; k_{n-j} \leq n\\k_1,\dotsc,k_{n-j} \neq i}} (-1)^{j-1} x_{k_1} \dotsc x_{k_{n-j}} }{    x_i \prod_{\substack{1 \leq k \leq n\\k \neq i}} (x_k - x_i) } \right]_n\text{.} $$  The author gives a hint by stating that the sum in the above numerator is just the coefficient of $x^{j-1}$ in the polynomial $(x_1-x)\dotsc(x_n-x)/(x_i-x)$; and he gives an intermediate result showing the explicit multiplication of the matrix and its inverse as  $$    \sum_{1 \leq t \leq n}b_{it}x_j^t    =    \frac{       x_j \prod_{\substack{1 \leq k \leq n\\k \neq i}} (x_k - x_j)    }{       x_i \prod_{\substack{1 \leq k \leq n\\k \neq i}} (x_k - x_i)    }    =    \delta_{ij}\text{.} $$  The only other hint as to the type of solution he was expecting is a reference to A. de Moivre's The Doctrine of Chances, 2nd edition, pp. 197-199, which deals with polynomial recurrence relations and difference products (available ).  At the least, I was just hoping someone could either verify the proof is correct at proofwiki and possibly fill in exactly how one identifies the $k$th order coefficient in the proof; or perhaps explain a proof strategy as to what steps to take where the intermediate result is obtained at some point before the final result.  Thanks so much for any help. Kernel requires an x86-64 CPU, but only detected an i686 CPU. How can I install Lubuntu/Ubuntu? I'm trying to install Lubuntu on my laptop (sorta old 2005). [Laptop stats: Intel® Celeron® CPU 410 @ 1.46 GHz 1.47GHz, 448 MB of RAM]  I press Install and this message appears:   This kernel requires an x86-64 CPU, but only detected an i686 CPU.  Unable to boot - please use a kernel appropriate for your CPU.   What can I do to install Lubuntu on my computer? I found this interesting problem in :     Given a point $P$ in space, and given a piece of malleable material of constant density, how should you shape and place the material in order to create the largest possible gravitational field at $P$?   Any ideas? Why do video cables (DVI, VGA) still screw in? I guess I could imagine that there was a time when accidentally disconnecting the monitor would have been catastrophic, though I don't see that being the case today.  Is it just a legacy holdover that they are still secured with screws?  Also, why is it that the video connection is really the only one that is still secured this way?  It seems like the power cable would be a better candidate to be secured with screws.  That really could be catastrophic.  In the end, the reason this question occurred to me is that I've never had a video cable come out when not screwed in, so why the significant security?