Updating from such repository can't be done securely, and is therefore disabled by default I'm trying to install Wacom Tablet Drivers on Ubuntu 18.04, Code:   sudo add-apt-repository ppa:doctormo/wacom-plus   However, I keep getting the error:   E: The repository 'http://ppa.launchpad.net/doctormo/wacom-plus/ubuntu bionic 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`   I have tried --allow-unauthenticated But it doesn't work. I also have deleted the Docker repository, as Raffa said in comments. Still no dice. Does anyone know any fixes? Thanks!
What can I do if a repository/PPA does not have a Release file? When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?
I accidentally removed all the packages starting with the name jpeg with:  sudo apt-get remove jpeg*   This screwed up a lot of things, removed Unity, Firefox, Flash player etc.  I somehow managed to recover the desktop and unity but then a lot of things are still buggy. For example .rpm files and .tag.gz just won't open up at all.  What I want is a way to fix everything that's amiss. Something that is the equivalent of a 'repair installation' with a windows disc.  Any tips, anyone? The system L0 is defined as follows:  Axioms: A1 (α → (β → α))  A2 2. (α → (β → γ) → ((α → β) → (α → γ))  A3 ((¬β → ¬α) → ((¬β → α) → β))  In one of my problem sheets, I am told that I am allowed to use the following theorem: if   ⊢ (α → α)    ⊢ (α → α) → (α → α)  My attempt to solve/prove the second one  ⊢ (α → α) → (α → α) choose 2 axioms which match.  α →α   β→α  γ→α  (α → (α → α) → ((α → α) → (α → α))  I'm struggling to see an obvious way of proving the theorem.  Is it provable? And if so, can you point me in the right direction?  Thanks a lot! Unsolved mystery - I was given a coworker's Ubuntu 12.04.1 LTS machine and set up my own (sudo/admin) user on there from the command line. I switched to my user (from his sudo/admin user) and confirmed everything was okay using the groups command and the /etc/passwd file looked great. After months of everything working perfectly, a power outage shut down the machine for the first time since I inherited it.  After booting, my new user disappeared. It's not in the /etc/passwd file and there is no entry in the /home directory. I created the user the same as I did before, and there were no errors to indicate that the user still existed.  What happened?  As requested, here is the output of   olduser@machine:~$ ls -lait /home  total 16  3408126 drwxr-xr-x 2 newuser newuser 4096 Nov 20 10:28 newuser  3407873 drwxr-xr-x 4 root root 4096 Nov 20 10:28 .  3407874 drwxr-xr-x 36 coworker coworker 4096 Nov 20 10:00 bvillupu  2 drwxr-xr-x 26 root root 4096 Oct 3 2012 ..  3408259 lrwxrwxrwx 1 root root 44 Aug 9 2012 .directory -&gt; /etc/kubuntu-default-settings/directory-home Are there wizarding schools in the rest of the "magical" world? Are there other schools for witches and wizards in the rest of the world? In the books they only speak of 3 schools, but what about Asian or American people?  And even more, were they affected by the events happening in Europe? Is there a way to determine the device running an application. I want to distinguish between iPhone and iPod Touch, if possible. Downcasting in Java Upcasting is allowed in Java, however downcasting gives a compile error.   The compile error can be removed by adding a cast but would anyway break at the runtime.   In this case why Java allows downcasting if it cannot be executed at the runtime? Is there any practical use for this concept?   public class demo {   public static void main(String a[]) {       B b = (B) new A(); // compiles with the cast,                           // but runtime exception - java.lang.ClassCastException   } }  class A {   public void draw() {     System.out.println("1");   }    public void draw1() {     System.out.println("2");   } }  class B extends A {   public void draw() {     System.out.println("3");   }   public void draw2() {     System.out.println("4");   } } Why is the spoken German in many US films and TV shows so inaccurate? Is there a reason why in so many English-language movies and TV series, whenever someone is speaking "German", they (actors, writers etc.) just don't care about if what they say is right or wrong? This can range from:    just minor grammatical errors e.g. "Schieß dem Fenster" in "Die Hard":                                rambling some made-up words and claiming them to be German e.g. "Lebenslangeschicksalssatz" in "How I met your mother"                                wrong German paired with a bad accent e.g. in "Scrubs"                                up to native German speakers talking complete nonsense e.g. Heidi Klum in HIMYM                                  I don't know if this is the same with other languages (for example there is a scene in Scrubs where the cast speaks Spanish, but there might be similar mistakes:                                 Do the creators and actors just not want to speak correct German and at least use correct German words, or is there simply no money in a $100,000,000 movie production to ask a native speaker to look over your script and maybe correct some of the lines? Installing "firmware-b43-installer" offline I need to convert one into 1, two into 2 and so on.  Is there a way to do this with a library or a class or anything? Why didn't Dumbledore just hunt Voldemort down? $f(z)$ and $\overline{f(\overline{z})}$ simultaneously holomorphic Compiling C code in the terminal Can't install Oracle JDK 9 I uninstalled jdk packages and now can't install them back. I managed to install oracle-java7-installer and oracle-java8-installer but can't install oracle-java9-installer. It seems that my computer tries to download wrong version of oracle-java9-installer 177 when version i would be able to download is 178.    $ wget http://download.java.net/java/jdk9/archive/178/binaries/jdk-9+178_linux-x64_bin.tar.gz --2017-07-21 11:00:02--  http://download.java.net/java/jdk9/archive/178/binaries/jdk-9+178_linux-x64_bin.tar.gz Connecting to 10.144.1.10:8080... connected. Proxy request sent, awaiting response... 200 OK Length: 293348142 (280M) [application/x-gzip] Saving to: 'jdk-9+178_linux-x64_bin.tar.gz'  jdk-9+178_linux-x64_bin.tar.gz     1%[&gt;                                                          ]   5.42M  5.04MB/s               ^C  $ wget http://download.java.net/java/jdk9/archive/177/binaries/jdk-9+177_linux-x64_bin.tar.gz --2017-07-21 11:00:16--  http://download.java.net/java/jdk9/archive/177/binaries/jdk-9+177_linux-x64_bin.tar.gz Connecting to 10.144.1.10:8080... connected. Proxy request sent, awaiting response... 404 Not Found 2017-07-21 11:00:17 ERROR 404: Not Found.   Can you help? apt-get tries to install Oracle JDK 9.  I run Ubuntu 16.04 in virtual machine hosted by win7  Full error message:  sudo apt-get install oracle-java9-installer Reading package lists... Done Building dependency tree        Reading state information... Done oracle-java9-installer is already the newest version (9b177-1~webupd8~0). 0 upgraded, 0 newly installed, 0 to remove and 147 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue? [Y/n] Y Setting up oracle-java9-installer (9b177-1~webupd8~0) ... Using wget settings from /var/cache/oracle-jdk9-installer/wgetrc Downloading Oracle Java 9... --2017-07-21 10:54:11--  http://download.java.net/java/jdk9/archive/177/binaries/jdk-9+177_linux-x64_bin.tar.gz Connecting to 10.144.1.10:8080... connected. Proxy request sent, awaiting response... 404 Not Found 2017-07-21 10:54:13 ERROR 404: Not Found.  download failed Oracle JDK 9 is NOT installed. dpkg: error processing package oracle-java9-installer (--configure):  subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing:  oracle-java9-installerE: Sub-process /usr/bin/dpkg returned an error code (1) Notepad doesn't open files created by Gedit? AutoScroll on chat exchange doesn't work in chrome 61 I updated the chrome to version 61, and the auto-scroll stopped working, it is necessary to scroll down the page manually. The problem does not occur in the previous version or in firefox.  Also, the reply icon no longer working when the message replied to is not in the current chat page. (Middle click still works and opens the link in new tab.) Can't get Freeglut to work with Haskell on Windows How can I check which songs or videos that I purchased from the iTunes Store have DRM restrictions?  All of the mobile OSes are very impressive to me at the moment, and I'm thinking about trying a non-iOS device again. I want to know now the impact it has on my Apple-sourced music collection though.  Is there a date cut-off for purchases when items went DRM free? Handling circular entity references with Migrate I am using  on a Drupal 6 to Drupal 7 migration right now.  I have three types: type1, type2, type3.  Each of the three types has a entityreference field on it, which is configured to be able to point to all three types.  This means that there can be circular references, and when a particular node is being migrated, the destination node may not exist yet and could potentially be any of the three types.  My migration class looks like this:  class MyNodeMigration extends DrupalNode6Migration {   public function __construct(array $arguments) {     parent::__construct($arguments);      $this-&gt;addFieldMapping('field_legacy_nid', 'nid');      $this-&gt;addFieldMapping('field_the_reference', 'field_the_reference')       -&gt;sourceMigration(array('type1', 'type2', 'type3');   } }  $node_arguments = array(   array(     'class_name' =&gt; 'MyNodeMigration',     'description' =&gt; 'type1',     'machine_name' =&gt; 'type1',     'source_type' =&gt; 'type1',     'destination_type' =&gt; 'type1',     'dependencies' =&gt; array('roles', 'users'),   ),    array(     'class_name' =&gt; 'MyNodeMigration',     'description' =&gt; 'type2',     'machine_name' =&gt; 'type2',     'source_type' =&gt; 'type2',     'destination_type' =&gt; 'type2',     'dependencies' =&gt; array('roles', 'users'),   ),    array(     'class_name' =&gt; 'MyNodeMigration',     'description' =&gt; 'type3',     'machine_name' =&gt; 'type3',     'source_type' =&gt; 'type3',     'destination_type' =&gt; 'type3',     'dependencies' =&gt; array('roles', 'users'),   ), );  $common_node_arguments = $common_arguments + array(   'user_migration' =&gt; 'users', );  foreach ($node_arguments as $arguments) {   $arguments = array_merge_recursive($arguments, $common_node_arguments);    Migration::registerMigration($arguments['class_name'], $arguments['machine_name'], $arguments); }   When I run the migrations, most nodes are fine, but I get a decent amount of Stubs (*) created.  Some of the destination nodes have the entityreference pointing to these Stub nodes.  The source nodes are fine.  What I have uncovered is that the bundle on the destination nodes that are being made as stubs are incorrect, and look like they are all type1.  A node of the proper type does end up being created, but it never gets set as the entityreference target.  Another way to explain this is that I end up with   node: nid=123, type=type1 node: nid=234, type=type1, field_the_reference=123 node: nid=345, type=type2   where it should be   node: nid=234, type=type1, field_the_reference=345 node: nid=345, type=type2   How do I handle this situation?  (*): a "Stub" in the context of this question here refers to a node which is created for the purpose of being a reference target, but does not get its data initially. The term is used throughout the Migrate documentation and source code. Overview of basic facts about Cauchy functional equation Mcrypt extension is missing in 14.04 server for mysql