I am getting errors while updating and upgrading kali linux  apt-get clean &amp;&amp; apt-get update &amp;&amp; apt-get upgrade -y &amp;&amp; apt-get dist-upgrade -y    error>  Ign:1 http://http.kali.org/kali sana InRelease                                  Ign:2 http://security.kali.org/kali-security sana/updates InRelease Err:3 http://http.kali.org/kali sana Release     404  Not Found Err:4 http://security.kali.org/kali-security sana/updates Release   404  Not Found Reading package lists... Done E: The repository 'http://http.kali.org/kali sana Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://security.kali.org/kali-security sana/updates Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   But doing just update doesnt give any errors  but upgrade does and due to this i am not able to install new applications what should i do?  I have changed repository address to  deb http://http.kali.org/kali kali-rolling main contrib non-free   and   deb http://old.kali.org/kali sana main non-free contrib   this from the official kali site   [kali][1]   and now getting the error >      Get:2 http://old.kali.org/kali sana InRelease [20.3 kB]                         Err:2 http://old.kali.org/kali sana InRelease                         The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository &lt;devel@kali.org&gt; Get:1 http://ftp.yzu.edu.tw/Linux/kali kali-rolling InRelease [30.5 kB] Err:1 http://ftp.yzu.edu.tw/Linux/kali kali-rolling InRelease   The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository &lt;devel@kali.org&gt; Reading package lists... Done W: GPG error: http://old.kali.org/kali sana InRelease: The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository &lt;devel@kali.org&gt; E: The repository 'http://old.kali.org/kali sana InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. W: GPG error: http://ftp.yzu.edu.tw/Linux/kali kali-rolling InRelease: The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository &lt;devel@kali.org&gt; E: The repository 'http://http.kali.org/kali kali-rolling InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   got this error.
I cannot update my Kali Linux, when trying to execute apt-get update I get this error message:  # apt-get update  Get:1 http://kali.mirror.garr.it/mirrors/kali kali-rolling InRelease [30.5 kB] Err:1 http://kali.mirror.garr.it/mirrors/kali kali-rolling InRelease   The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository &lt;devel@kali.org&gt; Reading package lists... Done W: GPG error: http://kali.mirror.garr.it/mirrors/kali kali-rolling InRelease: The following signatures were invalid: EXPKEYSIG ED444FF07D8D0BF6 Kali Linux Repository &lt;devel@kali.org&gt; E: The repository 'http://kali.mirror.garr.it/mirrors/kali kali-rolling InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   If you need my kernel version:  # uname -a 4.13.0-kali1-amd64 #1 SMP Debian 4.13.10-1kali2 (2017-11-08) x86_64 GNU/Linux   How can I fix this?
Best way to include pdfs in an app Behaviour of printf when printing a %d without supplying variable name I've just encountered a weird problem, I'm trying to printf an integer variable, but I forgot to specify the variable name, i.e.  printf("%d");   instead of  printf("%d", integerName);   Surprisingly the program compiles, there is output and it is not random. In fact, it happens to be the very integer I wanted to print in the first place, which happens to be m-1.  The errorneous printf statement will consistently output m-1 for as long as the program keeps running... In other words, it's behaving exactly as if the statement reads  printf("%d", m-1);   Anybody knows the reason behind this behaviour? I'm using g++ without any command line options.  #include &lt;iostream&gt; #define maxN 100 #define ON 1 #define OFF 0  using namespace std;  void clearArray(int* array, int n); int fillArray(int* array, int m, int n);  int main() {     int n = -1, i, m;     int array[maxN];     int found;      scanf("%d", &amp;n);      while(n!=0)     {         found=0;         m = 1;         while(found!=1)         {             if(m != 2 &amp;&amp; m != 3 &amp;&amp; m != 4 &amp;&amp; m != 6 &amp;&amp; m != 12)             {                 clearArray(array, n);                 if(fillArray(array, m, n) == 0)                 {                     found = 1;                 }             }             m++;         }          printf("%d\n");          scanf("%d", &amp;n);     }      return 0; }  void clearArray(int* array, int n) {     for(int i = 1; i &lt;= n; i++)         array[i] = ON; }  int fillArray(int* array, int m, int n) {     int i = 1, j, offCounter = 0, incrementCounter;      while(offCounter != n)     {         if(*(array+i)==ON)          {             *(array+i) = OFF;             offCounter++;                }         else          {             j = 0;             while((*array+i+j)==OFF)             {                 j++;             }             *(array+i+j) = OFF;             offCounter++;                    }         if(*(array+13) == OFF &amp;&amp; offCounter != n) return 1;         if(offCounter ==n) break;          incrementCounter = 0;                while(incrementCounter != m)         {             i++;             if(i &gt; n) i = 1;             if(*(array+i) == ON) incrementCounter++;          }            }      return 0; } My mother is given a UK tourist visa for 2 years with a duration of stay as 180 days. It is a c type multiple entry visa. Is this 180 days is the total stay she can take or is it duration of stay per visit.  Thanks in advance for your reply. Set multicolumn width to default table width JavaScript 64 bit numeric precision Is there a way to represent a number with higher than 53-bit precision in JavaScript? In other words, is there a way to represent 64-bit precision number?  I am trying to implement some logic in which each bit of a 64-bit number represents something. I lose the lower significant bits when I try to set bits higher than 2^53.  Math.pow(2,53) + Math.pow(2,0) == Math.pow(2,53)   Is there a way to implement a custom library or something to achieve this? Why is     $$\lim_{n \to \infty} \frac{2^n}{n!}=0\text{ ?}$$   Can we generalize it to any exponent $x \in \Bbb R$? This is to say, is     $$\lim_{n \to \infty} \frac{x^n}{n!}=0\text{ ?}$$     This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: . Why can rm remove read-only files? How might the weight of a falling object affect the damage it causes? Fall damage is 1d6 per 10 feet. What adjustments if any should I make for objects falling on a player character? (e.g. a bear)  Assuming the objects are meaningful threats but not instant character death, should the weight of an object change the calculation, e.g. more then 1d6 per 10 feet.  Or is this more in the spirit of improvising damage chart? i.e. the setback (cat to face) dangerous (orc fell on me), and deadly (the large bear).  If this is house-rule territory does any one have any experience or advice beyond  relevant to 5e. List the files accessed by a program Possible Duplicate:          I was wondering if there's any good reason to still use blob fields in a database. A couple of years ago I worked with a DB with a bunch of images in it, the DB was very slow and I couldn't see any good reason to keep the images inside the DB, so I got the images out and stored the filenames instead.  Was this a smart move? What would you do in my place? Not enough free disk space when upgrading Near-universally applicable alternative to "sanity check" The phrase "sanity check" is  as it implies that there is something wrong with people who have mental illnesses and the word "sanity" has been used to discriminate against such people.  Therefore, it should should be avoided.  What is a better alternative in the context of software?  Example usage:     _: if this is not what it should be, we have memory corruption (a fatal   error) and should terminate the program. Why is it impossible, without attempting I/O, to detect that TCP socket was gracefully closed by peer? As a follow up to a , I wonder why it is impossible in Java, without attempting reading/writing on a TCP socket, to detect that the socket has been gracefully closed by the peer? This seems to be the case regardless of whether one uses the pre-NIO Socket or the NIO SocketChannel.  When a peer gracefully closes a TCP connection, the TCP stacks on both sides of the connection know about the fact. The server-side (the one that initiates the shutdown) ends up in state FIN_WAIT2, whereas the client-side (the one that does not explicitly respond to the shutdown) ends up in state CLOSE_WAIT. Why isn't there a method in Socket or SocketChannel that can query the TCP stack to see whether the underlying TCP connection has been terminated? Is it that the TCP stack doesn't provide such status information? Or is it a design decision to avoid a costly call into the kernel?  With the help of the users who have already posted some answers to this question, I think I see where the issue might be coming from. The side that doesn't explicitly close the connection ends up in TCP state CLOSE_WAIT meaning that the connection is in the process of shutting down and waits for the side to issue its own CLOSE operation. I suppose it's fair enough that isConnected returns true and isClosed returns false, but why isn't there something like isClosing?  Below are the test classes that use pre-NIO sockets. But identical results are obtained using NIO.  import java.net.ServerSocket; import java.net.Socket;  public class MyServer {   public static void main(String[] args) throws Exception {     final ServerSocket ss = new ServerSocket(12345);     final Socket cs = ss.accept();     System.out.println("Accepted connection");     Thread.sleep(5000);     cs.close();     System.out.println("Closed connection");     ss.close();     Thread.sleep(100000);   } }   import java.net.Socket;  public class MyClient {   public static void main(String[] args) throws Exception {     final Socket s = new Socket("localhost", 12345);     for (int i = 0; i &lt; 10; i++) {       System.out.println("connected: " + s.isConnected() +          ", closed: " + s.isClosed());       Thread.sleep(1000);     }     Thread.sleep(100000);   } }   When the test client connects to the test server the output remains unchanged even after the server initiates the shutdown of the connection:  connected: true, closed: false connected: true, closed: false ... For random variables $X \in \mathbb{R}^h$, and a positive semi-definite matrix $A$: Is there a simplified expression for the expected value, $\mathop {\mathbb E}[Tr(X^TAX)]$ and variance, $Var[Tr(X^TAX)]$? Please note that $A$ is not a random variable. Whenever I start an application like Terminal or Preview, they are always opened as a small window on the top left corner of the screen. Is there any way to set them to open in the center of the screen? Preferably maximized too? How do I set a static IP address in Windows? Cannot set up multiple desktops (workspaces) Publish and/or subscribe to Platform Events between separate Orgs? How can I send the stdout of one process to multiple processes using (preferably unnamed) pipes in Unix (or Windows)? I'd like to redirect the stdout of process proc1 to two processes proc2 and proc3:           proc2 -&gt; stdout        /  proc1        \           proc3 -&gt; stdout   I tried   proc1 | (proc2 &amp; proc3)   but it doesn't seem to work, i.e.   echo 123 | (tr 1 a &amp; tr 1 b)   writes   b23   to stdout instead of    a23  b23 I have a script that reads a text stream and generates a file of sed commands that is later run with sed -f. The generated sed commands are like:  s/cid:image002\.gif@01CC3D46\.926E77E0/https:\/\/mysite.com\/files\/1922/g s/cid:image003\.gif@01CC3D46\.926E77E0/https:\/\/mysite.com\/files\/1923/g s/cid:image004\.jpg@01CC3D46\.926E77E0/https:\/\/mysite.com\/files\/1924/g   Assume the script which generates the sed commands is something like:  while read cid fileid do     cidpat="$(echo $cid | sed -e s/\\./\\\\./g)"     echo 's/'"$cidpat"'/https:\/\/mysite.com\/files\/'"$fileid"'/g' &gt;&gt; sedscr done   How can I improve the script to ensure all regex metacharacters in the cid string are escaped and interpolated properly?