In the past hour, we've had 9 10 meta posts reporting various bugs. Pages are showing no questions, questions are getting flipped/mixed up, etc. Clearly, this is not a coincidence. Stack Exchange is going crazy!  I see nothing posted on , so I want to know: what is causing this? Is it caching? Localization? Just some turbulence in the servers? Or has the spammer threatening to hack us actually succeeded? :P  (To devs: please post the cause of this on StackStatus if you find it.)
The entire  site is blank right now.  The header and footer are shown, but no questions.
How to set system-wide environment variables on OS X Mavericks $\sigma$-algebra vs. $\sigma$-field: is there any difference? The subject says it all: is there any difference between the two concepts of $\sigma$-algebra and $\sigma$-field? In probability theory, they seem to be used more or less interchangeably. If there is no difference, is there any historical reason why some people/schools use the term $\sigma$-algebra, while others use the term $\sigma-$field? How do open files behave on linux systems? What is the most efficient way to clone a JavaScript object? I've seen obj = eval(uneval(o)); being used, but . I've done things like obj = JSON.parse(JSON.stringify(o)); but question the efficiency.  I've also seen recursive copying functions with various flaws.  I'm surprised no canonical solution exists. How to use a variable for a key in a JavaScript object literal? Unbounded continuous function on non-compact metric space Suppose $(S,d)$ is a non-compact metric space. Is it possible to construct an unbounded continuous function from $S$ to $\mathbb{R}$? If it is possible, please show the construction method :)  Here's my attempt to solve this problem: Because $S$ is not compact, we can find a neighborhood assignment function $N(x)$ so that a finite cover is not possible. Then each time we can find an uncovered point from the union of neighborhoods before, and change the function by $f(x):=max\{f(x),\text{a function which equals to the indice of this point at that point and gradually vanishes at further points from the selected point}\}$. However I'm concerned that while this function is unbounded, there may be some invalid points for this function (goes to infinity)...  EDIT: As I found out there is a duplicate question, however the elementary solution is not presented in that question, so I still wish to know about this problem. :) No Dialect mapping for JDBC type: -9 with Hibernate 4 and SQL Server 2012 Does anyone know the general strategy for summing a series of the form:  $$\sum_{n=1}^{\infty} \frac{1}{n^2 + a^2},$$  where $a$ is a positive integer?  Any hints or ideas would be great! import Excel sheets by name Dual Booting win 10 and Ubuntu 18.04 on two separate physical ssds I have gotten as far as to create the bootable usb, booting into that bootable usb and getting to the install options however i quit because I had some concerns.  I currently have a Samsung 850 evo 1tb that has win 10ninstalled. I want to dual boot with Ubuntu 18.04 by installing it on a brand new unformatted uninitialized Samsung 860bevo 250gb. Should i format the brand new ssd as a new volume in win 10 and then proceed with the Ubuntu install on this volume. What else should i do? Im a first time Ubuntu user and installer.  Any and all help is appreciated. iOS 7 Locked Bug via Ubuntu 13.10 I wanted to bring up an issue with the latest Ubuntu release that I hope can be solved. Although I will agree with the community that iOS 7 is not the most open platform release, it still is my desire to be able to grab Photos, Music, and Files off my Phone similar to what I would do to any other device.  Every time I connect my device to Ubuntu, I receive the following notification:  The device "Justin's iPhone" is locked. Enter the passcode on the device and click "Try again".   On my iPhone, I select the following   Unfortunately, this is where problems start to arise. It appears that Ubuntu either does not recognize the permissions from my iPhone or the iPhone is not allowing itself to truly be unlocked. As we can see the permissions are   Browsing askubuntu, I encountered the following   After running the code, I receive the following error:  justin@justin-CT15:~$ idevicepair unpair &amp;&amp; idevicepair pairERROR: Device d1fea2c56e51199f901eb34020a1581ea31a2a50 is not paired with this host   If I call the command again, i receive another error:  justin@justin-CT15:~$ idevicepair pair ERROR: Could not pair with the device because a passcode is set. Please enter the passcode on the device and retry.   Ultimately, I am stuck to experiment with solutions that end up not working. I am troubled by the lack of information and support for the iOS 7 platform on Ubuntu's latest release. If anyone has a workable solution or experiment for a workaround, I am happy to try  Thanks for reading and have a wonderful day! How to draw commutative diagrams? Can anyone help me in giving commands for commutative diagrams in LaTeX ? It doesn't seem to appear properly in the LaTeX guides that I have. A command for a simple triangular diagram with arrows associated to maps would be good enough, or maybe some appropriate reference. Interview Question Asked In yahoo Can you find the smallest positive number such that if you shuffle the digits of the number in a particular order, the shuffled number becomes twice the original number.  Source:   I understand the answer is $125874 =&gt; 251748$  $251748$ is twice the $125874$ and have same digits $1,2,4,5,7$ &amp; $8$  but how to solve this non programmatic ? Print programs with its proper syntax I have defined my own language whose syntax is very close to the one of Pascal. I would like to type the following program for instance. Many people use the packages algorithmicx or algorithm2e to print programs, but it seems that we have to use their specific keywords of its syntax like procedure, end while.  I just want to indent spaces when needed, and bold some words when I want (sorry that I could not bold letters in the following figure). Do I have to use  texttt for each line? Also, with verbatim, I could not bold words...  Also, as the program is not large, I would need to put it on the left side of the page, and leave space for some explanasion text on its right hand side. So I  guss I need to get them all together, and use multicols.  Could anyone help?  program test                                      some text here var   i : integer;                                    ...    b : boolean; begin    i := 1;                                        ...    b := true;    while i &lt; 15 do       i := i  + 1;       b := not b                                  some text here    od end   Edit1: Following @Werner's tabbing solution, I have made the code a minipage:  \begin{minipage}[t]{0.48\linewidth}% \begin{tabbing} Werner's solution \end{tabbing} \end{minipage}\hfill \begin{minipage}[t]{0.48\linewidth} a paragraph \end{minipage}   Actually as the code shows, I want the texts to be another separated minipage on the right hand side of the code. I have then 2 questions:   is it reasonable to make 0.48\linewidth instead of 0.5\linewidth? 0.48\linewidth is a conventional choice? is it possible to make a frame around the code, and use \caption and \label to make it a reference (I prefer figures)? How to perform hard / cold reboot of iPhone or iPad? What is the best word describing the nature of expiring in a short amount of time, connoting "losing public attention"? Is there an adjective that describes the nature of expiring, connoting a sense of losing public attention, in a very short amount of time? For example,  In a fast-paced era, news articles are ____. During the 1990s, compared with traditional technologies, computer  technologies are ___; for example, a new generation of CPU technologies usually comes out every one to two years.  (I thought about &quot;perishable,&quot; but it does not seem connoting &quot;losing public attention.&quot;) No reputation for editing questions? Running this script on: "Red Had Enterprise Linux Server release 5.11 (Tikanga)"  Mail is: version 8.1 6/6/93 (appears quite old).  Have tried various things and cannot seem to get this to work..  echo "Email message" | mail -a /home/user/checks/notprocessed.txt -a /home/user/checks/dirlist.txt -s "Subject" recipient@company.com /home/user/checks   Resulting message:     mail: invalid option -- a   mutt is not installed and I have limited access to this system as it is owned by the company I work for.  I could add in other components, but has to go through change management, and related processes.  uuencode is not available either.  Here is what I am using today and I am trying to add a second file to:  if grep 'Not Empty' /home/user/checks/notprocessed.txt    then    echo "files were found";     SUBJECT="NIGHTLY DIRECTORY LISTING OF FILES SENT TO VENDOR";    FROM="SENDER&lt;sender@company.com&gt;"    # EMAIL="JOHN DOE&lt;recipient@company.com&gt;"    EMAIL="MARY DOE&lt;recipient@company.com&gt;";    /bin/mail -s "$SUBJECT" "$EMAIL" -- -f "$FROM" &lt; /home/user/checks/notprocessed.txt /home/user/checks/dirlist.txt     exit -20 fi   And..  /home/user/checks/dirlist.txt is not attached or included as part of the e-mail.  I would like /home/user/checks/dirlist.txt to be actually an attachment  This actually does work - but includes the notprocessed.txt as the body of the email..  if grep 'Not Empty' /home/user/checks/notprocessed.txt    then    echo "files were found";     SUBJECT="NIGHTLY DIRECTORY LISTING OF FILES SENT TO VENDOR";    FROM="SENDER&lt;sender@company.com&gt;"    # EMAIL="JOHN DOE&lt;recipient@company.com&gt;"    EMAIL="MARY DOE&lt;recipient@company.com&gt;";    /bin/mail -s "$SUBJECT" "$EMAIL" -- -f "$FROM" &lt; /home/user/checks/notprocessed.txt     exit -20 fi Is it possible to use the enumerate/itemize environment within the proof/remark environment in a nice way? What is the probability that the selected function maps prime numbers to prime numbers? Let $X = \{1, 2, 3, . . . , 25\}$. If a student selects a function randomly from the set of all functions from $X$ onto $X$, then what is the probability that the selected function maps prime numbers to prime numbers ? No idea how to proceed, please guide.