I am a new ubuntu use. please help me out here.  apt-get update   Output:  Reading package lists... Done W: chmod 0700 of directory /var/lib/apt/lists/partial failed - SetupAPTPartialDirectory (1: Operation not permitted) E: Could not open lock file /var/lib/apt/lists/lock - open (13: Permission denied) E: Unable to lock directory /var/lib/apt/lists/ W: Problem unlinking the file /var/cache/apt/pkgcache.bin - RemoveCaches (13: Permission denied) W: Problem unlinking the file /var/cache/apt/srcpkgcache.bin - RemoveCaches (13: Permission denied)
I get this error whenever I try to install programs using the terminal:  home@ubuntu:~$ apt-get install myunity E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?   Also I'm unable to install updates using the terminal.
Label and caption without float I’d like to have an environment that works much like a float, except that it doesn’t float.  That is, in fact, I’d like to be able to define an environment that has a label and a caption.  I explicitly do not want to use a floating environment, though. For one thing, floats do many things fancy which I just don’t need, nor want (such as spacing) and for another, floats have their share of problems (for example consider the problem of ).  Is there a ready-made way to achieve this? Of course, I could always write my own based on the result of the other answer, i.e. harnessing \refstepcounter. But I’m not sure how to use that, documentation is scarce, and I’d prefer an existing solution. I've seen many posts regarding a combinatorial proof of the following question. But for a non-combinatorial proof would the following method work? Also... is this the easiest way to arrive at a proof? It seems to be rather verbose.  Show the formula $k {n\choose k} = n {n-1 \choose k-1}$ is true for all integers $n,k$ with $0\le k \le n$.  My answer:  Observe that  $$\begin{align*} {n\choose k}&amp;= \frac {n}{k} {n-1 \choose k-1}\\ &amp;= \frac {n}{k}\left[ {n-2 \choose k-2} + {n-2 \choose k-1}\right]\\ &amp;= \frac {n}{k}\left[ \frac{(n-2)!}{(k-2)!(n-2-(k-2))!} + \frac {(n-2)!}{(k-1)!(n-2-(k-1))!}\right]\\ &amp;= \frac {n}{k}\left[ \frac{(n-2)!}{(k-2)!(n-k)!} + \frac {(n-2)!}{(k-1)!(n-k-1)!}\right]\\ &amp;= \frac{(n-1)!}{(k-1)!(n-k)!} + \frac {(n-1)!}{(k)!(n-k-1)!}\\ &amp;= \frac{(n-1)!}{(k-1)!(n-1-(k-1))!} + \frac {(n-1)!}{(k)!(n-1-k)!}\\ &amp;={n-1 \choose k-1} + {n-1 \choose k}={n \choose k}. \end{align*}$$ So I did a fresh install of Ubuntu 20.04 on a computer with the new RTL8125B Realtek network card and I cannot get the network to work. I was very suprised since this is supposed to be the new feature of the 5.4 kernel (I have 5.4.0-26-generic installed). Does anyone have any idea on how to get it working? Thank you. $ lspci -knn | grep Eth -A3 06:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller [10ec:8125] (rev 04) Subsystem: ASUSTeK Computer Inc. RTL8125 2.5GbE Controller [1043:87d7] Kernel modules: r8169 07:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/570X/580/580X/590] [1002:67df] (rev e7)  $ dmesg | grep -i r8169 [    0.911236] r8169 0000:06:00.0: unknown chip XID 641 Cannot modify files installed by `snap` I have installed a package using snap and I need to modify one of the files but when I try to change its ownership or permissions, I always get the following message:  sudo chmod +x ./my_file.js chmod: changing permissions of '/snap/my_app/my_file.js': Read-only file system   How can I modify files that are installed via snap? How to select even or odd elements based on class name if you create html layout like so  &lt;ul&gt;      &lt;li class='a'&gt;&lt;/li&gt;      &lt;li class='b'&gt;&lt;/li&gt;      &lt;li class='a'&gt;&lt;/li&gt;      &lt;li class='b'&gt;&lt;/li&gt;      &lt;li class='a'&gt;&lt;/li&gt;      &lt;li class='b'&gt;&lt;/li&gt;      &lt;li class='a'&gt;&lt;/li&gt;      &lt;li class='b'&gt;&lt;/li&gt; &lt;/ul&gt;   and try to select odd elements with 'a' class like so $$('.a:odd') you will get empty array, and if you do $$('.a:even') you will get all four li elements with 'a' class.. It really strange.. But im new to mootools, maybe im doing something wrong..    So my question is how to select first and third li elements with a class. I know that i can do it with function like this  $$('.a').filter(function(item, index) { return index%2; }  but its too complicated for such small task as selecting odd or even elements.. Do cards with abilities that target trigger heroic? Cannot use polyglossia/babel with biblatex in LuaTeX: etoolbox Toggle undefined This is an example test.tex document. Both babel and polyglossia failed and produce the same error: \documentclass{book}  %\usepackage[vietnamese]{babel} \usepackage{polyglossia} \setdefaultlanguage{vietnamese}  \usepackage{biblatex}   \title{Sth}  \begin{document}  \maketitle  \end{document}   is the full log. And my config for VS Code: &quot;latex-workshop.latex.recipes&quot;: [     {         &quot;name&quot;: &quot;lualatex-&gt;biber&quot;,         &quot;tools&quot;: [             &quot;lualatex&quot;,             // &quot;biber&quot;,         ]     } ], &quot;latex-workshop.latex.tools&quot;: [     {         &quot;name&quot;: &quot;lualatex&quot;,         &quot;command&quot;: &quot;lualatex&quot;,         &quot;args&quot;: [             &quot;--shell-escape&quot;,             &quot;-synctex=1&quot;,             &quot;-interaction=nonstopmode&quot;,             &quot;-file-line-error&quot;,             &quot;-pdf&quot;,             &quot;%DOC%&quot;         ]     },     {         &quot;name&quot;: &quot;biber&quot;,         &quot;command&quot;: &quot;biber&quot;,         &quot;args&quot;: [             &quot;%DOCFILE%&quot;         ]     } ],  I installed all Vietnamese-related package I found using tlmgr search, notably babel-vietnamese and vntex, to no avail. When I use English language, it works. When I paste the exact document to Overleaf, it also works. So it's something on my part. How can I fix this? Remove preinstalled apps on Big Sur MacBook Pro M1 Sorry for my English, I'm French and  I have  tried a lot (even with SIP disabled) but nothing works. I'm kind very desperate since I’m not sure how I would set up screen time to limit my children’s usage of the Pre-installed apps. The reason why I need to do so, is that my kid waste time in stead of studying. Is there a guide how to set this up? To be short, I want to copy a folder to a location /usr/share/screenlets/.... in Ubuntu 10.04 system. I tried by logging in as root from terminal giving su.   I even changed my user account type to ADMINISTRATOR; Yet, no use. PASTE option in the context menu's list in the folder /usr/share/... is INACTIVE.  How can I copy those files? Using something like this:  try:    # Something... except Exception as excep:    logger = logging.getLogger("component")    logger.warning("something raised an exception: " + excep)    logger.info("something raised an exception: " + excep)   I would rather not have it on the error-level cause in my special case it is not an error. I committed and joined  in private beta. As per private beta privilege page casting close and reopen votes requires only 1 reputation. So anyone is able to access close votes and reopen votes review queues. But there is no link of the review page in the top bar or anywhere. So I thought I am not able to access any review queue. I opened the review page by typing the URL manually (to see review statistics for curiosity). But I found that I can access close &amp; reopen votes review queues.        Probably I won't be able to access any review queue if I have less than 350 and the site goes to public beta. But during private beta off topics, unclear, or closable questions are likely to come. So it is very important to close/reopen them during private beta.  So can we please add the "review" link in the top bar if I am able to review some queues? What element saved Iron Man from his blood poisoning? I just watched Iron Man 1&amp;2 the other day. I'm new to the entire story. In IM2 we learn that his blood is being poisoned and that he has tried every combination of every existing element as a cure - unsuccessfully. Then he deducts &quot;the key&quot; from the Expo park's plans which saves him. What is that key? What element had he not tried? I realize that the movie story has to be simplified, compared to the original story, so there are probably story elements that I have completely missed because they're only in the original works. We also saw that in LOTR. How to add coloured line before caption? ascending/descending in LINQ - can one change the order via parameter? Regex for parsing directory and filename I'm trying to write a regex that will parse out the directory and filename of a fully qualified path using matching groups.  so...  /var/log/xyz/10032008.log   would recognize group 1 to be "/var/log/xyz" and group 2 to be "10032008.log"  Seems simple but I can't get the matching groups to work for the life of me.  NOTE:  As pointed out by some of the respondents this is probably not a good use of regular expressions.  Generally I'd prefer to use the file API of the language I was using.  What I'm actually trying to do is a little more complicated than this but would have been much more difficult to explain, so I chose a domain that everyone would be familiar with in order to most succinctly describe the root problem. Deriving upper bound for derivative of analytical function $f$ is an analytical function on the unit disk $\mathbb{D}$ for which there is a $C &gt; 0$ such that  $\forall z \in \mathbb{D} \colon |f(z)| \leq \dfrac{C}{1-|z|}$.  I know have to prove that    $\forall z \in \mathbb{D} \colon |f'(z)| \leq \dfrac{4C}{(1-|z|)^2}$.  I tried using the Cauchy integral formula but I can't find a fitting circle to get this result. How can a point-particle have properties? I have trouble imagining how two point-particles can have different properties.  And how can finite mass, and finite information (ie spin, electric charge etc.) be stored in 0 volume?  Not only that, but it can also detect all fields without having any structure. Maybe it can check curvature of spacetime to account for gravity, but how can a point contain the information of what the other fields-vectors are? This seems to mean that also the information/volume in space is infinite.  Mathematically, a point cant have any intrinsic structure, so how does physics which is a mathematical theory explain this? Restricing domains for universal and existential quantifiers I am currently using Rosen's "Discrete Mathematics and Its Applications" (7th ed.) for my discrete mathematics course. We recently talked about quantifiers, more specifically the universal and existential quantifier. What confuses me is when we started talking about restricting the domain (i.e. instead of all real numbers, only all real positive numbers), where does the conditional statement come from when restricting the domain of a universal quantifier and where does the conjunction come from when restricting the domain of a existential quantifier?  This link did help:   However, the part that confuses here is how are the domains restricted in the answer given in the link above? reCaptcha v1 is shutting down on March 31, but SEDE still uses it According to this , I thought the new recaptcha API was used network-wide. Though today, when going to  (which for whatever reasons never recognized me automatically), I got this message instead of a usable captcha image.   V1 Unsupported Please direct siteowner to   (Doing a second try doesn't show this message anymore, and the recaptcha v1 works as intended.)  According to , the reCAPTCHA v1 API will stop working on March 31, 2018:  What happens to reCAPTCHA v1? Any calls to the v1 API will not work after March 31, 2018. Starting in November 2017, a percentage of reCAPTCHA v1 traffic will begin to show a notice informing users that the old API will soon be retired. Most websites around the world have already switched to reCAPTCHA v2, where humans pass effortlessly. With our advanced risk analysis engine, reCAPTCHA v2 can effectively separate humans from bots and always stay ahead of the attackers. If your site still uses reCAPTCHA v1, please upgrade to reCAPTCHA v2 immediately. We no longer support reCAPTCHA v1. Any calls to the v1 API will not work after March 31, 2018. Please register a new key and upgrade to v2.  I'm really hoping this will not take  to fix, because we've only got three and a half weeks left! Testing Classification on Oversampled Imbalance Data I am working on severely imbalanced data. In literature, several methods are used to re-balance the data using re-sampling (over- or under-sampling). Two good approaches are:   SMOTE: Synthetic Minority Over-sampling TEchnique () ADASYN: Adaptive Synthetic Sampling Approach for Imbalanced Learning ()   I have implemented ADASYN because its adaptive nature and ease to extension to multi-class problems.  My question is how to test the oversampled data produced by ADASYN (or any other oversampling methods). It is not clear in the mentioned two paper how they performed their experiments. There are two scenarios:  1- Oversample the whole dataset, then split it to training and testing sets (or cross validation).  2- After splitting the original dataset, perform oversampling on the training set only and test on the original data test set (could be performed with cross validation).  In the first case the results are much better than without oversampling, but I am concerned if there is overfitting. While in the second case the results are slightly better than without oversampling and much worse than the first case. But the concern with the second case is if all minority class samples goes to the testing set, then no benefit will be achieved with oversampling.  I am not sure if there are any other settings to test such data.