Codelite 13.0 can't be installed in Ubuntu 18.04
Unable to correct problems, you have held broken packages
L293, L298 and SN754410 H-bridge drivers on low voltage power supply How do I reset a lost administrative password? I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution? What is the difference between apt and apt-get? Create any number of paragraph fields in a multiple value field on node create form I have a paragraphs field that takes a term reference.  I need to count how many terms there are for a specific vocabulary and then create that many instance of the paragraphs multiple value field for when creating a node of a certain type. Can this be done with Hook_form_alter ?  It is important that these fields are loaded when the node creation form is loaded rather than the user having to click add more  Any help would be greatly appreciated  I have tried this but when saving the node it doesn't save the new fields  function hook_form_alter(&amp;$form, $form_state, $form_id) {    if ($form_id == 'my_form') {    $item = $form['field_features']['widget']['0'];    // get taxonomy terms   $query = \Drupal::entityQuery('taxonomy_term');   $query-&gt;condition('vid', "my_voc");   $tids = $query-&gt;execute();   $terms = \Drupal\taxonomy\Entity\Term::loadMultiple($tids);    $count = count($terms);    $i = '1';   foreach($terms as $term){     $form['field_features_para']['widget'][$i] = $item;     $form['field_features_para']['widget'][$i]['#delta'] = $i;     $form['field_features_para']['widget'][$i]['#weight'] = $i;     $i ++;   }  } } What is the correct way to completely remove an application? How to write a while loop with the C preprocessor? I am running a fresh install of Linux Mint Nadia (14). I am following the instructions on Vagrant  but have gotten stuck on the . It seems the Vagrant box cannot connect outside and so I can't install anything using either Chef or Puppet.  In the basic Vagrant resolve.conf contains nameserver 10.0.2.3. But with that set I can't ping us.archive.ubuntu.com.  If I change it to 8.8.8.8 then I can ping us.archive.ubuntu.com but it does not stay set, and after a reboot it changes back to 10.0.2.3 - so provisioning fails again.  Ideally I would like for 10.0.2.3 to work on my setup. Failing that I would like a way to permanently change resolv.conf so that I can do provisioning. A problem from Isaacs' FGT This is problem 3B.12. from the afore mentioned book. It asks to show that, if $G$ is a solvable Frattini-free group (that is, $Φ(G)=1$) and $H$ is a subgroup of some maximal subgroup $M$ of $G$, then $G$ contains a subgroup of index $|M:H|$. It is easy to see that, if   $N \unlhd G$ and $M\cap N=1$, then $G=MN$, $M\cong G/N $ and $H\cong K/N $ for some $ K \leqslant G $, where $K$ contains $N$. Then $|G:K|=|G/N:K/N|=|M:H| $ and we are done. However, the hypothesis will not necessarily hold. But, if $N$ is minimal among normal subgroups of $G$ (in the sense of containment), then $N$ is elementary abelian, hence nilpotent, which implies that $M \cap N \lneq N_G(  M \cap N ) \cap N $. Thus, $M \lneq N_G(  M \cap N )$ and by the maximality of $M$ we deduce that $M \cap N \unlhd G$. So, for this particular $M$, if it is not true that there exists some normal subgroup of $G$ with which it intersects trivially, then $M \cap N = N$ by the minimality of $N$. Hence $M$ contains every minimal subgroup of $G$.     How should I proceed from here? Encouraging software publishers to use StackExchange as support mechanism Whenever I deal with an application publisher's custom support mechanism because I can't see any evidence of activity on StackExchange, I always wish they'd just migrate to StackExchange, particularly when I get a prompt response from them. What a waste, I think, that my question and answer weren't captured on SE.  In cases where there is some activity for the application on SE, I'll post my question there and, if I get no response, reference the SE question in my email follow-up. In the case of , that had a happy ending where the support person posted the answer to the SE site at the same time they emailed me.  My related meta questions are:   Are there any obvious downsides to publishers effectively "giving up" their custom support mechanisms, or at least their custom forum, in favor of the appropriate SE site? Are there any obvious downsides to SE for publishers making this transition? Is SE staff engaged in any systematic marketing efforts to get publishers to make this transition? Is there any SE documentation which lists the advantages of publishers making this transition? Change Folder Permissions I started off with changing to the folder I want to change permissions for, and that is the opt folder.  $ cd /opt/ test@testVM:/opt$   So I tried changing the permissions for this folder now using:  sudo chmod 775   And that hasn't worked. It showed this message:  Try 'chmod --help' for more information.   There is something I am forgetting or leaving out.  Please can you show me what I am doing wrong?  Thanks in advance. Why is it bad practice to test for item names? I've heard that testing for item names and lores in Minecraft JE is bad practice. For example, the following commands are not good: execute if entity @e[nbt={Inventory:[{tag:{display:{Name:'[{&quot;text&quot;:&quot;Test Thing&quot;}]'}}}]}] clear @p minecraft:diamond{display:{Name:'{&quot;text&quot;:&quot;Shiny…&quot;}'}} 0 clear @p minecraft:netherite_sword{display:{Lore:['{&quot;text&quot;:&quot;A Mysterious Sword&quot;}']}} 0  Why are these commands considered bad practice? Are they prone to failure and may not work? And what can I do to fix them? Note that this only applies to reading item names, not setting them. The following are not considered bad practice and in fact are the only ways to accomplish these tasks: give @p minecraft:diamond{display:{Name:'{&quot;text&quot;:&quot;Shiny…&quot;}'}} replaceitem @p weapon.mainhand minecraft:netherite_sword{display:{Lore:['{&quot;text&quot;:&quot;A Mysterious Sword&quot;}']}} I need to compile between two and four times before I see changes I make in the editor (TeXstudio) and each time I compile, a new .tex file is created with random letters and numbers at the end.   For example, If I create the file hello.tex and compile two to four times I'll get the file,   hello.tex.QU6664      then I make some small changes in the editor and compile two to four times I'll get the additional file,   hello.tex.Ak6664   After continuing to do this (each time compiling between two to four times before I see the changes I made), I now have many files that look like  hello.tex.QU6664, hello.tex.Ak6664, hello.tex.YX6664, hello.tex.sN6664, hello.tex.Ss6664, ...   A little bit of additional information (in case it's relevant): Everything was working fine up until a few days ago, i.e. only needed to compile once and only the file hello.tex was created. I still only get one .aux,  .synctex and .pdf files. I use TeXstudio to write and compile. I don't think it has anything to do with the bibliography (I tried removing bibliography altogether and still having the same problem).  How do I prevent these additional files from appearing and only compiling once like I used to? Has anyone had a similar problem? Why isn't apt full-upgrade getting an updated software key signature for skype After a recent apt update &amp;&amp; apt full-upgrade I started getting the following error when running apt full-upgrade subsequently: Get:4 https://repo.skype.com/deb stable InRelease [4,502 B]                                         Err:4 https://repo.skype.com/deb stable InRelease   The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository &lt;se-um@microsoft.com&gt; W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://repo.skype.com/deb stable InRelease: The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository &lt;se-um@microsoft.com&gt; W: Failed to fetch https://repo.skype.com/deb/dists/stable/InRelease  The following signatures were invalid: EXPKEYSIG 1F3045A5DF7587C3 Skype Linux Client Repository &lt;se-um@microsoft.com&gt; W: Some index files failed to download. They have been ignored, or old ones used instead.  Is there a way to correct this, or is it down to Microsoft/Canonical to produce/update the necessary key signatures? I was told that computers with more than 2 gig's memory need a 64 bit operating system to utilize all RAM.  Is the 64bit Ubuntu download really JUST for AMD processors? I am asking because the disk image I downloaded says AMD64.  So will my new Intel 2.3Ghz Core i3 Dual Core processor work with 64 bit Ubuntu?  It runs the 64bit version of Windows without any qualm. Django: manage.py does not print stack trace for errors Convergence test of the series $\sum\sin100n$ I need to prove that $$\sum_{n=1}^{\infty} {\sin{100n}} \; \text{diverges}$$ I think the best way to do it is to show that $\lim_{n\to \infty}{\sin{100n}}\not=0$. But how do I prove it? Imaginary line on the Earth is straight or not? I was watching Google map. Saw a line which is joinging north to south pole. It is going between middle of China and Mexico. But, the line is not straight. Tried to search in net but not able to get anything. Can anyone check and let me know  or Is there an uncountable family of infinite parts of $\mathbb N$ with two to two intersection finite? Choosing OpenLayers or Leaflet? I was debating with one of my collegues on OpenLayers v/s Leaflet. I made a point that OpenLayers is much better API if we wish to build a project, where you need direct connectivity to the Geoserver and PostGIS.  Then I found , which looks pretty new but has the features of connectivity with the Geoserver and PostGIS.  So my project details are as follows,   Use the map interface to fetch Feature Info Create a customized tool that takes the lat/lon from user as to where he/she clicks on the map and then fetches the Climate Data from the raster (which is handled by a py script on the server) Allows user to upload excel, which is sent to the py script, which returns a GeoJSON, which creates Vector Features on the map Allow user to create vector polygons, which will fetch the Features it intersects from the WFS Layer. Fetches Layer from the PostGIS Datastore on GeoServer and displays the layers on the map.   So now I am confused on which is better and why using OpenLayers over Leaflet makes more sense or not? t-test for partially paired and partially unpaired data 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).