Ubuntu 19.04 apt update fails Update from such a repository securely E: The repository 'http://archive.ubuntu.com/ubuntu disco Release' no longer has 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://archive.ubuntu.com/ubuntu disco-updates Release' no longer has 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://archive.ubuntu.com/ubuntu disco-security Release' no longer has 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.   sources.list  deb http://archive.ubuntu.com/ubuntu disco main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu disco-updates main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu disco-security main restricted universe multiverse
How to install software or upgrade from an old unsupported release? Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc
Tips for getting really good answers on SO XMLHttpRequest Origin null is not allowed Access-Control-Allow-Origin for file:/// to file:/// (Serverless) Equivalence principle question I understand the  as "The physics in a freely-falling small laboratory is that of special relativity (SR)." But I'm not quite sure why this is equivalent to "One cannot tell whether a laboratory on Earth is not actually in a rocket accelerating at 1 g". How to create a new object instance from a Type One may not always know the Type of an object at compile-time, but may need to create an instance of the Type.    How do you get a new object instance from a Type? Getting ssh to execute a command in the background on target machine How to get exact camera view? I'm currently a beginner when it comes to 3D modelling but doing okay so far. I'm struggling a bit when it comes to the final renders of my scene, specifically on the camera view I want. Sometimes its to zoomed in and sometimes to zoomed out that it's gone out of the environment of the blender. I realized the settings for the camera on blender are for actual cameras / photography and I'm no expert on that too. A tip on how to control them precisely would be nice. Thank you. Frequently loaded packages: Differences between pdfLaTeX and XeLaTeX Until now, I have been compiling my LaTeX documents with pdfLaTeX. My standard document preamble includes the "usual suspects" for non-English speakers (, , ) and a bunch of other packages. Assuming I were to convert to XeLaTeX, what modifications of my preamble are advisable? I'm aware that the expansion=true option of the  package is not (yet) available for XeLaTeX, and that  is sort of a default package for OpenType fonts. What other packages (and package options) should be removed and, vice versa, incorporated when switching from pdfLaTeX to XeLaTeX? (Google) Title of page not updated, everything else did My website changed significantly this month.  Amongst the changes was the website's title.  Two weeks ago, I finally used Webmaster Tools and submitted the page.  So far, Yahoo and Bing have updated the title in the search results, but not Google.  I've resubmitted via Webmaster Tools the website, and the bots have crawled the page, and have added "content keywords".  But the title still doesn't match.  The "content keywords" lists many of the words in the new title (but contains keywords of the existing title also).  Must say that 4 of the top 5 key words in the "significance" list are the new title's.  Still, no change.  Any remedies for this problem?  Is adding the "alt" tag for the logo significant enough to trigger the change?  There isn't an appropriate place to put the company name between  tags on the front page.  Any suggestions?  Thanks. Invite people who liked my first page to like another one in Facebook Feedback Request: New Timeline Question View There is an experimental timeline view for questions now available on meta ONLY! (Now working on SO, SF, and SU as well)  This is partially motivated by comments about how difficult it is to follow very active questions which have a lot of activity, and also the feedback on the API which was heavily dominated by "we need to know what happened in this time range" type responses.  It can only be accessed through URL hackery at the moment. To get to it, enter question URLs like so:  https://meta.stackexchange.com/posts/{id}/timeline  This is a chronological timeline of everything that happened on a question, including   initial question ask answers  revisions comments closure, deletion, reopen, undelete, etc votes   all based on when they happened in chronological order.  We are thinking about making this a fourth tab on the question, like so:  Timeline | Oldest | Newest | Votes  Please try it out and provide feedback. It is still a little rough, so we are not looking for highly detailed bug reports, just more general feedback.  Timeline view for this question: Changing email addresses on my @me.com and @icloud.com I will be writing scripts for ArcGIS Desktop in Python with ArcPy.   Is there a community or open source project where code and models can be shared? I've previously used the default Email app on my CyanogenMod 7 EVO because I had an Exchange account at work. However, I switched jobs recently and my new place just uses GMail corporate accounts (which I enjoy). Since I don't have the Exchange account anymore, I'd like to move over to the GMail app because I prefer the UI and whatnot, but I can't for the life of me find any kind of "Select All" functionality in it.  The Email app allows me to do this from the options menu (Menu-&gt;Select All selects everything in the current folder). In GMail I noticed that if I select one or more items, then "Deselect All" becomes available in the options menu, but not "Select All". I've also tried various forms of long-pressing on messages, accounts, and folders to no avail.  Is there any way to do this in the GMail app, or am I just stuck without it? I searched the issue tracker and didn't find anything relevant, which surprised me a bit, to be honest. Obviously I can do this from a computer if I need to empty a folder/label, but I'd kind of like to retain the functionality on my phone, too. Am I missing some non-obvious (or perhaps even obvious) menu item somewhere? override Home key in android ICS How to get the environment variables of a subprocess after it finishes running? What methods can be used to micro-adjust autofocus of a camera body to a particular lens? I have a Canon 7D with a 50mm f/1.4 lens, and I think the auto-focus of the lens is off.  How can I test and adjust this reliably?  Will this approach work with all of my lenses? If I had a different camera body, would I have other/different options? Is there a "null coalescing" operator in JavaScript? Is there a null coalescing operator in Javascript?  For example, in C#, I can do this:  String someString = null; var whatIWant = someString ?? "Cookies!";   The best approximation I can figure out for Javascript is using the conditional operator:  var someString = null; var whatIWant = someString ? someString : 'Cookies!';   Which is sorta icky IMHO. Can I do better? How do I close a connection early? In  (the original movie), Marty comes back from 1955 10 mins early to prevent Doc from being shot (which he fails at). He then rolls up to the Lone Pine Mall and sees himself hit 88 mph and shoot back to 1955 (again). Marty then carries on with this life as usual. What happens to the Marty that goes back to 1955 at the end of the film?  This obviously is a recursive problem where it would create another timeline and Marty would keep coming back 10 mins early to view another Marty zip back to 1955? "Yesterday" time specification shown when it was actually the day before yesterday