I have a question about sending big documents to the database. When i insert my edited word doc with colors on some words into tinyMCE the text display properly. But sending to the database fails because of commas in the text i guess. Is there a simple way to fix this?
If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?
I have a batch file which I use to create an .apk file on my Windows machine. Now I need to be able to create the .apk file in Ubuntu but I don't know how translate my .bat file to a script to be able to run it on Ubuntu.  Below is the batch file which works fine on Windows.  Will you please give me some hints on how I can run it on Ubuntu?  @echo off set PAUSE_ERRORS=0 :user_configuration  :: Path to Flex SDK  set FLEX_SDK=C:\sdk\flex_sdk_4.5.1.21328  :: Path to Android SDK set ANDROID_SDK=C:\sdk\android  :validation if not exist "%FLEX_SDK%\bin" goto flexsdk if not exist "%ANDROID_SDK%\platform-tools" goto androidsdk goto succeed  :validation if not exist "%FLEX_SDK%\bin" goto flexsdk if not exist "%ANDROID_SDK%\platform-tools" goto androidsdk goto succeed  :flexsdk echo. echo ERROR: incorrect path to Flex SDK echo. if %PAUSE_ERRORS%==1 pause exit  :androidsdk echo. echo ERROR: incorrect path to Android SDK in 'bat\SetupSDK.bat' echo.  if %PAUSE_ERRORS%==1 pause exit  :succeed set PATH=%PATH%;%FLEX_SDK%\bin set PATH=%PATH%;%ANDROID_SDK%\platform-tools  :: Android packaging set AND_CERT_NAME="PeymanApp" set AND_CERT_PASS=fd set AND_CERT_FILE=cert\SampleApp.p12 set AND_ICONS=icons/android  set AND_SIGNING_OPTIONS=-storetype pkcs12 -keystore "%AND_CERT_FILE%" -storepass     %AND_CERT_PASS%  :: Application descriptor set APP_XML=application.xml  :: Files to package set APP_DIR=bin set FILE_OR_DIR=-C %APP_DIR% .  :: Your application ID (must match &lt;id&gt; of Application descriptor) set APP_ID=air.com.doitflash.SampleApp  :: Output packages set DIST_PATH=dist set DIST_NAME=PeymanApp  :validation %SystemRoot%\System32\find /C "&lt;id&gt;%APP_ID%&lt;/id&gt;" "%APP_XML%" &gt; NUL if errorlevel 1 goto badid goto end_validation  :badid echo. echo ERROR: Application ID (APP_ID) does NOT match Application descriptor '%APP_XML%'     (id)  echo.  :end_validation  set TARGET= set PLATFORM=android  ::call bat\Packager.bat if "%PLATFORM%"=="android" goto android-config  :android-config set CERT_FILE=%AND_CERT_FILE% set SIGNING_OPTIONS=%AND_SIGNING_OPTIONS% set ICONS=%AND_ICONS% set DIST_EXT=apk set TYPE=apk goto start  :start if not exist "%CERT_FILE%" goto certificate :: Output file set FILE_OR_DIR=%FILE_OR_DIR% -C "%ICONS%" . if not exist "%DIST_PATH%" md "%DIST_PATH%" set OUTPUT=%DIST_PATH%\%DIST_NAME%%TARGET%.%DIST_EXT% :: Package  echo true echo. call adt -package -target %TYPE%%TARGET% %OPTIONS% %SIGNING_OPTIONS% "%OUTPUT%"     "%APP_XML%" %FILE_OR_DIR% -extdir lib/ echo. if errorlevel 1 goto failed goto end  :certificate echo Certificate not found: %CERT_FILE% echo.  if %PAUSE_ERRORS%==1 pause exit  :failed echo APK setup creation FAILED.  if %PAUSE_ERRORS%==1 pause exit  :end Prove that  $ n &lt; 2^{n}  $ for all natural numbers $n$.  I tried this with induction: Inequality clearly holds when $n=1$. Supposing that when $n=k$, $k&lt;2^{k}$. Considering $k+1 &lt;2^{k}+1$, but where do I go from here?  Any other methods maybe? Let mods see the names of the flaggers for chat offensive flags There have been    (not to pick on the Bridge, just that these are the ones I found) occurrences where users abuse chat flags to cause drama. Random stuff gets flagged, and users from other rooms are needlessly summoned into the room. The issue is, while mods can tell the room to stop flagging random things, there's no way to enforce this. Spam/offensive flags in chat are anonymous, and can be abused with impunity without the mods finding out. I don't think there's anything stopping a user from letting out an endless stream of flags, annoying everyone. Can mods have the ability to see who flagged a message in chat? Clearly this is an edge case and I probably shouldn't have even tried awarding the bounty to a deleted answer, but why is the bounty award button even available?  It's not a bug since someone added in the notification seen in the final image.  But that sure seems like a roundabout way to let the user know that they can't award a bounty to a deleted answer.  The second step is particularly strange since the system really ought to know that the warning is pointless: no bounty can be awarded.  My suggestion is to rip-off the  and let bounties be awarded without the warning.  Then remove the single click button from deleted answers. Story about an intelligent, walled city; people are reproduced by machines, protagonist rebels and tries to leave Directory index forbidden by Options directive If you have a conducting hollow sphere with a uniform charge on its surface, then will the electric field at every point inside the shell be 0. The reason the electric field is 0 at the center is clear from the symmetry of the sphere, but for a point at a certain distance from the center, shouldn't a net electric field exist?  I saw a similar question on the site but it was vaguely explained. What word describes random unfitting accusations I really dont know how to describe this. Im having a discussion with someone, I was sharing information that I found on a topic. Randomly im called out as being rude when nowhere was there evidence of rudeness exchanged. This person seems to have a history of claiming people have a problem or are being rude out of the random blue.   Is there a word to describe these random accusations that dont connect to anything? I'm trying to write a basic program in C using gedit or sublime text (which I prefer), but no matter what I do when I try to compile or run, or even while writing, I have no option to use 'stdio.h' or any similar package. Even when I start typing #include &lt;st the only word completion sublime suggests is 'struct'.  I've read dozens of threads, but all managed to fix this by installing gcc, which I've tried to reinstall multiple times, with no luck.  This is the output from gcc -v:  Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper OFFLOAD_TARGET_NAMES=nvptx-none OFFLOAD_TARGET_DEFAULT=1 Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 7.2.0-8ubuntu3' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 7.2.0 (Ubuntu 7.2.0-8ubuntu3) `   This is the code:   #include &lt;stdio.h&gt;  int main(void) { printf("hello, world\n"); }   When I compile using gcc, I get nothing, no error at least. but when I try to run using just ./hello.c this is what I get. How can I analytically prove that randomly dividing an amount results in an exponential distribution (of e.g. income and wealth)? In this current  the following is being proposed:      Suppose you randomly divide 500 million in income among 10,000   people. There's only one way to give everyone an equal, 50,000 share.   So if you're doling out earnings randomly, equality is extremely   unlikely. But there are countless ways to give a few people a lot of   cash and many people a little or nothing. In fact, given all the ways   you could divvy out income, most of them produce an exponential   distribution of income.   I have done this with the following R code which seems to reaffirm the result:  library(MASS)  w &lt;- 500000000 #wealth p &lt;- 10000 #people  d &lt;- diff(c(0,sort(runif(p-1,max=w)),w)) #wealth-distribution h &lt;- hist(d, col="red", main="Exponential decline", freq = FALSE, breaks = 45, xlim = c(0, quantile(d, 0.99)))  fit &lt;- fitdistr(d,"exponential") curve(dexp(x, rate = fit$estimate), col = "black", type="p", pch=16, add = TRUE)     My question How can I analytically prove that the resulting distribution is indeed exponential?  Addendum Thank you for your answers and comments. I have thought about the problem and came up with the following intuitive reasoning. Basically the following happens (Beware: oversimplification ahead): You kind of go along the amount and toss a (biased) coin. Every time you get e.g. heads you divide the amount. You distribute the resulting partitions. In the discrete case the coin tossing follows a binomial distribution, the partitions are geometrically distributed. The continuous analogues are the poisson distribution and the exponential distribution respectively! (By the same reasoning it also becomes intuitively clear why the geometrical and the exponential distribution have the property of memorylessness - because the coin doesn't have a memory either). Why didn't Sauron become invisible while wearing the One Ring? I'm curious as to why Sauron is the only being/person shown wearing the One Ring who does not become invisible?   Isildur, Gollum, Bilbo, Frodo, and Samwise all become invisible while wearing the One Ring.  Why didn't Sauron become invisible while wearing the one ring?  I became interested after reading Pearsonartphoto's question asking what effect wearing the One Ring would have had on . Deriving the conditional distributions of a multivariate normal distribution We have a multivariate normal vector ${\boldsymbol Y} \sim \mathcal{N}(\boldsymbol\mu, \Sigma)$. Consider partitioning $\boldsymbol\mu$ and ${\boldsymbol Y}$ into  $$\boldsymbol\mu = \begin{bmatrix}  \boldsymbol\mu_1 \\  \boldsymbol\mu_2 \end{bmatrix} $$ $${\boldsymbol Y}=\begin{bmatrix}{\boldsymbol y}_1 \\  {\boldsymbol y}_2 \end{bmatrix}$$  with a similar partition of $\Sigma$ into $$  \begin{bmatrix} \Sigma_{11} &amp; \Sigma_{12}\\ \Sigma_{21} &amp; \Sigma_{22} \end{bmatrix} $$ Then, $({\boldsymbol y}_1|{\boldsymbol y}_2={\boldsymbol a})$, the conditional distribution of the first partition given the second, is  $\mathcal{N}(\overline{\boldsymbol\mu},\overline{\Sigma})$, with mean $$ \overline{\boldsymbol\mu}=\boldsymbol\mu_1+\Sigma_{12}{\Sigma_{22}}^{-1}({\boldsymbol a}-\boldsymbol\mu_2) $$ and covariance matrix $$ \overline{\Sigma}=\Sigma_{11}-\Sigma_{12}{\Sigma_{22}}^{-1}\Sigma_{21}$$  Actually these results are provided in Wikipedia too, but I have no idea how the $\overline{\boldsymbol\mu}$ and $\overline{\Sigma}$ is derived. These results are crucial, since they are important statistical formula for deriving Kalman filters. Would anyone provide me a derivation steps of deriving $\overline{\boldsymbol\mu}$ and $\overline{\Sigma}$ ? Thank you very much! How (and why) use stderr for both reading and writing? According to , less reads navigation commands from stderr if it's not able to open /dev/tty.  This seems puzzling, since I've never seen anything write to another program's stderr stream, and I don't know how I would even accomplish that.  What is the purpose of stderr being open for both reading and writing? And if this is useful, how do I make use of it on modern systems? (Is there some arcane syntax to pipe something into stderr instead of stdin, for instance?) Installing gcc-7 (and newer packages) in Ubuntu 16.04 Links being changed to cppreference.com Someone just edited a link in one of my answers to point to a 'better reference'.    I've no problem with links being changed in general, but this smells like part of a concerted attempt to redirect traffic.   Is this kind of activity acceptable on SO? If I'm logged in to a system via SSH, is there a way to copy a file back to my local system without firing up another terminal or screen session and doing scp or something similar or without doing SSH from the remote system back to the local system? How can I add an empty directory to a Git repository? How can I add an empty directory (that contains no files) to a Git repository? Convert date to another timezone in JavaScript $E[e_te_s\Delta B_t\Delta B_s]$ for $\Delta B_t$ Brownian motion increments and $e_t(\omega)$ a measurable function. If there are injective homomorphisms between two groups in both directions, are they isomorphic? If I have two groups, $G$ and $H$ and two injective homomorphisms $\phi:G \to H$ and $\psi: H \to G$, then by the first isomorphism theorem applied to $\phi$, we have that $G \cong \mathrm{Im} (\phi)$, a subgroup of $H$. Similarly, $H$ is isomorphic to a subgroup of $G$. For finite groups, this guarantees that $G \cong H$ but does this hold for infinite groups?  Weird things can happen for infinite groups, e.g $n\mathbb Z \subsetneq \mathbb Z$ but $n \mathbb Z \cong \mathbb Z$. I'm wondering if this kind of thing stops an isomorphism from occurring.  I think this question generalises to rings, modules, fields and so on. Can this be answered for all of these structures?