How to upgrade from 19.10 to 20.04?
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How can I set up Samba shares to only be accessed by certain users? I have a RAID10 array mounted on Ubuntu Server 12.04. I have created a few folders within the mount point and want the following functionality.  There will be 4 users, 3 of them are windows users: 'one' 'two' &amp; 'three'. 'four' is a media streamer that only needs to access the MEDIA share. One Two and Three need to have full access to the media share and their own personal shares (for documents) which no other users but them can access.  Currently, User Four works perfectly (Has full access to the MEDIA folder and can't access folders owned by other users). The problem is, when logged in as the other user, I can't access either share; (tried using valid users =  and using chmod to add permissions to no avail).  TL;DR: I need to know how to configure Samba properly to restrict access to certain shares for certain users and allow all of them to access one communal folder (all files on a RAID10 mount). Why couldn't River Song's memories bring back The Doctor in the rebooted universe? In the season 5 finale of Doctor Who, in the wedding ceremony of Amy, River Song showed up outside the door. Moments later, we discovered that she gifted Amy her blank diary which was supposed to contain information about The Doctor. It means River Song remembered The Doctor.  Memories of The Doctor was able to bring The Doctor back to existence in the rebooted Spacetime. Why couldn't River Song's memories work? Why does $\lim_{n\to\infty}(1+\frac{1}{n})^n = e$ instead of $1$? On Wikipedia, it says that $\lim_{n\to\infty}(1+\frac{1}{n})^n = e$ :     It [e] is approximately equal to 2.71828,[1] and is the limit of (1 + 1/n)n as n approaches infinity, ... ()   When I evaluate $(1+\frac{1}{n})^n$ for $n = 10^8$, I get approximately $2.718281798347$ which indeed is pretty close to $e$.  But when I try to "solve" the limit using the laws of limits, I get  $$\lim_{n\to\infty}\left(1+\frac{1}{n}\right)^n = \left(\lim_{n\to\infty}\left(1+\frac{1}{n}\right)\right)^n$$  because of the power law  $$ = \left(\lim_{n\to\infty}(1)+\lim_{n\to\infty}\left(\frac{1}{n}\right)\right)^n$$  because of the addition law  $$=\left(1+0\right)^n = 1$$  but that would mean that $e=1$, which is obviously not true.  What am I missing / doing wrong?  Thanks in advance. I followed the beginner steps for creating a .  The child theme was created and it appears as an option on my Themes page. But unlike the other Themes on the page (including its parent), there is no preview.  The other themes ("Twenty Twelve," "Twenty Thirteen," and "Twenty Fourteen") are all listed with an image preview.  My child theme ("Twenty Fourteen Child") does not have any image. The child theme can be applied without issue.  This issue arises when I create child themes from other themes as well. Any ideas why this is happening and if I can resolve? stop Ipod from asking for old Apple ID password Run a command without making me wait On the CLI, sometimes a command I type takes a while to complete, and sometimes I know when that's about to happen. I'm a bit confused on "backgrounding" and such in Linux.  What is the most common (or user-friendly way) of telling the CLI that I don't want to wait, please give me back my prompt immediately. And if it could give me a progress bar or just busy-spinner, that would be great! Why is plain-hash-then-encrypt not a secure MAC? How to make equally sized windows in corners of the screen? combining results of two select statements Why is the atmosphere transparent in the visible spectrum? One of the great 'coincidences' in physics is that the Sun happens to shine most brightly at exactly the wavelengths our eyes can see; it's an easy explanation that our eyes evolved to make the most out of what was available.  However, this spectral window is also , with Rayleigh scattering and the ozone layer protecting us from the UV and strong water vapour absorption in the IR until way into the radio range.  My question is: is this a coincidence? Were there geological factors that made it so? Or is it just lucky chance? (I also notice other planets in our neighbourhood weren't quite so lucky.) Or had atmospheric absorption been different our eyes would have tuned to whatever spectral window were brighter as a whole? I have a very simple component:  PushTopicTest.cmp &lt;aura:component implements="flexipage:availableForAllPageTypes" access="global"&gt;     &lt;lightning:empApi aura:id="empApi"/&gt;     &lt;aura:handler name="init" value="{!this}" action="{!c.onInit}"/&gt; &lt;/aura:component&gt;    PushTopicTestController.js ({     onInit: function(component, event, helper) {         var empApi = component.find("empApi");         empApi.setDebugFlag(true);         empApi.subscribe("/topic/AccountChanges?Id=0011t0000033C9QAAU", -1, function(message) {             console.log("Event Received : " + JSON.stringify(message));         });     } })   I also have PushTopic created like this:   What I am trying to do, is to only receive events for specific record Id. Based on documentation this should work: "/topic/AccountChanges?Id=0011t0000033C9QAAU", but it doesn't.   "/topic/AccountChanges" works though.  I've tried Id='0011t0000033C9QAAU' aswell, but no luck.  Do you know if it is possible at all? How do I fill arrays in Java? As a(n) noun vs as only How to access the Keyboard Layout Options in 13.10+ How to UPSERT (MERGE, INSERT ... ON DUPLICATE UPDATE) in PostgreSQL? $SU(3)$ irreducible representations with tensor method I am dealing with the tensor product representation of $SU(3)$ and I have some problems in understanding some decomposition.  1) Let's find the irreducible representation of $3\otimes\bar{3}$  we have that this representation trasforms like   $${T^\prime}^i_j=U^i_k {U^{\dagger}}^l_j T^k_l $$  hence I observe that  $$Tr(T)=\delta^j_iT^i_j$$ is an invariant and so  $$T^i_j=\left(T^i_j-\frac{1}{3}\delta^j_iT^i_j\right)+\frac{1}{3}\delta^j_iT^i_j$$  allows me to write $$3\otimes\bar{3}=8\oplus1$$ Here comes my questions: I have heard that this $8$ representation is an "$8_{MA}$" where MA is for "mixed-antisymmetric". The meaning of "mixed-antisymmetric" shold be: "the tensor $\left(T^i_j-\frac{1}{3}\delta^j_iT^i_j\right)$ should be antisymmetric for an exchange of 2 particular indexes but not for a general exchange of 3 indexes". What does this mean? I see only 2 index in that tensor.  2) Consider this representation: $$3\otimes3\otimes3=3\otimes(6\oplus\bar{3})=3\otimes6_S\oplus3\otimes\bar{3}=3\otimes 6_S\oplus8_{MA}\oplus1$$  and now on my notes I have $$3\otimes6_S=10_S\oplus8_{MS}$$  Where "MS" is for "mixed symmetric": symmetric for an exchange of 2 particular indexes but not for a general exchange of 3 indexes.  I could not demonstrate this last decomposition using tensor method. I started noticeing that: $$3\otimes6_S=q^iS^{k,l}$$ where $S^{k,l}$ is a symmetric tensor But then I am not able to proceed in demonstrating the above decomposition (note: I would like to demonstrate this decomposition using only tensor properties, not Young tableaux). I tried to look on Georgi, Hamermesh, Zee and somewhere online but I have not found any good reference which explains well this representatin decomposition...  EDIT: the demonstration should not include the use of Young diagrams...my professor started the demonstration by writing $\epsilon_{\rho,i,k}q^i S^{k,l}=T'^l_\rho=8_{MS}$ and then stopped the demonstration. So I wanted to make some minecoins and I also heard that anyone become a marketplace creator could but I don't know where to apply. I'm in Minecraft Pocket Edition 1.14.30. Can you tell me where I can apply? Given $a>b>2$ both positive integers, which of $a^b$ and $b^a$ is larger? Given $a&gt;b&gt;2$ both positive integers, which of $a^b$ and $b^a$ is larger?  I tried an induction approach. First I showed that if $b=3$ then any $a \geq4$ satisfied $a^b&lt;b^a$.  Then using that as my base case I tried to show that given any pair of positive integers $a,b$ satisfying $a&gt;b&gt;2$ and $a^b&lt;b^a$, then $(a+1)^{b+1}&lt;(b+1)^{a+1}$ - but that is where I got stuck.  Any help would be appreciated. Prove: If a linear map, $φ: U→V$ is bijective, then $φ(x)=0$ has only the solution $x=0$. How do I upgrade from 14.04 LTS to 16.04.1 LTS?