Wrong source.list entry
How do I remove a malformed line from my sources.list?
Not a problem, but have been seeing questions recently of people not being offered upgrade from 18.04 to 20.04.  I thought these upgrades were offered back in June.  I upgraded to 20.04 from 19.10 and this was offered back in May.  Imagine that different versions paths have different schedules, but google does not help explaining(that I found).  Does someone know the schedules? I would like to convert a Mp4 file in HD into a Mp4 file of lower resolution. Is there any software that can be used for this? Why no ooVoo on ubuntu? The only reason I ever boot into Windows (7) is to use the popular video chat software ooVoo (). It's useless under Wine and there seems to be no way to run it in Ubuntu except for some proprietary tools. Does anyone have any information on some alternatives to running it with Wine? Why don't I get a link error when I provide my own malloc and free? An investigator wishes to produce a combined analysis of several datasets.  In some datasets there are paired observations for treatment A and B.  In others there are unpaired A and/or B data.  I am looking for a reference for an adaptation of the t-test, or for a likelihood ratio test, for such partially paired data.  I am willing to (for now) to assume normality with equal variance and that the population means for A are the same for each study (and likewise for B). Eigenspace of the companion matrix of a monic polynomial How do I prove that the eigenspace of an $n\times n$ companion matrix  $$ C_p=\begin{bmatrix} 0 &amp; 1 &amp; 0 &amp;\cdots &amp; 0\\ 0 &amp; 0 &amp; 1 &amp;\cdots &amp; 0 \\ \vdots&amp;\vdots &amp;\vdots&amp;\ddots&amp;\vdots\\ 0 &amp; 0 &amp; 0 &amp;\cdots &amp;1 \\ -\alpha_0 &amp;-\alpha_1 &amp;-\alpha_2 &amp;\cdots&amp;-\alpha_{n-1} \end{bmatrix} $$ equals $\operatorname{Span}\{v_{\lambda} \} $ where $v_{\lambda}$ is an eigenvector of the companion matrix w.r.t. the eigenvalue $\lambda$: $$ v_{\lambda} =  \begin{bmatrix} 1 \\ \lambda\\ \lambda^{2} \\ \vdots\\ \lambda^{n-1} \end{bmatrix}. $$ How can I get the Cartesian product (every possible combination of values) from a group of lists?  Input:   somelists = [    [1, 2, 3],    ['a', 'b'],    [4, 5] ]   Desired output:  [(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), (2, 'a', 5) ...] What is a lambda (function)? For a person without a comp-sci background, what is a lambda in the world of Computer Science? How to grep for text in a file and display the paragraph that has the text? Below is the text in the file:  Pseudo name=Apple Code=42B state=fault  Pseudo name=Prance Code=43B state=good   I need to grep for "42B" and get the output from the above text like:   Pseudo name=Apple Code=42B state=fault   Does anyone have idea on how to achieve this using grep/awk/sed? How to use the symbol \angle at the section title Executing SSIS 2012 package that has script components from external application How to close entire application when application has more than 2 forms without showing messagebox more than once I have recently installed Ubuntu 14.04 LTS on my laptop Sony Vaio VPCEA16FG. I have been getting system freezes (everything including display, mouse, keyboard stops working and I have to do a restart with the power switch) and there are random popups of "System program problem Detected"  On startup my screen is all splashed with black and white pixels and a System program problem detected message.  My video card info:    01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Madison [Mobility Radeon HD 5650/5750 / 6530M/6550M How does the referral system work? I don't understand how the referral program works even after reading everything about it. Do I only get the 500 CC if the referred person subscribes within 14 days, or if I just refer the person? And do I get 500 CC for every month that referred person subscribes, or is it just one time? 5v output to 3.3v? I have a microcontroller and a Raspberry Pi, both running off of the same 5v supply, in parallel. The microcontroller has 4 5v output pins and the other is a Raspberry Pi, that can only accept inputs of 3.3v and less.    Obviously I cannot directly connect the outputs to the inputs - that'll fry the Raspberry Pi.    How can I connect 5v outputs to the GPIO pins on the Raspberry Pi? How to parse HTML with PHP? I am trying to work out how to get the value of table cell for each row using jQuery.  My table looks like this:  &lt;table id="mytable"&gt;   &lt;tr&gt;     &lt;th&gt;Customer Id&lt;/th&gt;     &lt;th&gt;Result&lt;/th&gt;   &lt;/tr&gt;   &lt;tr&gt;     &lt;td&gt;123&lt;/td&gt;     &lt;td&gt;&lt;/td&gt;   &lt;/tr&gt;   &lt;tr&gt;     &lt;td&gt;456&lt;/td&gt;     &lt;td&gt;&lt;/td&gt;   &lt;/tr&gt;   &lt;tr&gt;     &lt;td&gt;789&lt;/td&gt;     &lt;td&gt;&lt;/td&gt;   &lt;/tr&gt; &lt;/table&gt;   I basically want to loop through the table, and get the value of the Customer Id column for each row.  In the code below I have worked out that I need to do this to get it looping through each row, but I'm not sure how to get the value of the first cell in the row.  $('#mytable tr').each(function() {     var cutomerId =  } How can we differentiate between change and progress in the area of history and natural sciences? Evaluate the integral $\int_0^\infty \frac{dx}{\sqrt{(x^3+a^3)(x^3+b^3)}}$ Custom post type - posts list - white screen of death i am getting a weird error - white screen in the list of posts for a specific Custom post type (just for that one)   tried deactivating all the plugins tried checking for error (debugging = true)   Still nothing the page just doesnt echos anything... (nothing in source too)  I am talking about such a url in the admin:     Here is register_post_type part i am using:    function register_submodelcpt() {     $labels = array(         'name'                  =&gt; __('Sub Models', THEME_NAME),         'singular_name'         =&gt; __('Sub Models', THEME_NAME),         'add_new'               =&gt; __('New Model', THEME_NAME),         'add_new_item'          =&gt; __('Add new Model', THEME_NAME),         'edit_item'             =&gt; __('Edit Model', THEME_NAME),         'new_item'              =&gt; __('New Model', THEME_NAME),         'all_items'             =&gt; __('All Sub Models', THEME_NAME),         'view_item'             =&gt; __('Watch Model', THEME_NAME),         'search_items'          =&gt; __('Search Models', THEME_NAME),         'not_found'             =&gt;  __('No Models found', THEME_NAME),         'not_found_in_trash'    =&gt; __('No Models found in trash', THEME_NAME),          'parent_item_colon'     =&gt; '',         'menu_name'             =&gt; __('Sub Models', THEME_NAME),      );      $args = array(         'labels'                =&gt; $labels,         'public'                =&gt; true,         'publicly_queryable'    =&gt; true,         'show_ui'               =&gt; true,          'show_in_menu'          =&gt; true,          'query_var'             =&gt; true,         'rewrite'               =&gt; array('slug' =&gt; 'submodels'),         'capability_type'       =&gt; 'post',         'has_archive'           =&gt; true,          'hierarchical'          =&gt; true,         'menu_position'         =&gt; 5,         'menu_icon'             =&gt; get_stylesheet_directory_uri().'/images/cpt/subcars.png',                     'supports'              =&gt; array('title', 'thumbnail', 'revisions', 'page-attributes')     );      register_post_type('submodelscpt',$args); } add_action('init', 'register_submodelcpt');   Did anyone encounter such an issuse? can you think of a reason this might happen?   Another weird thing when i change this:    To this:     The posts list loads correctly...