Edit: This is not asking how to get Ubuntu to remember WiFi passwords. I'm asking for the opposite.  Most of the other questions I find ask how to get Ubuntu's NetworkManager to stop forgetting the WiFi password. Instead, here I'm wondering how to get it to forget the password each time. That is, for security purposes, I would like it so that I would manually need to choose a WiFi network and enter its password each time I start Ubuntu and login. I already know how to get it to stop automatically connecting to a network, but not how to get it to be amnestic about passwords.
I'm connecting to some enterprise wireless network (eduroam).  The thing is that it saves the User/Password in the wireless settings, anyone can click 'Show password' and see my university account password.  What I want is that it prompts me everytime the credentials inputs when I try to connect to the network and don't save it under the 'settings' page.  Is this possible? If yes, how?  Thanks  Ubuntu 18.04 LTS
How to reinstall default packages In an attempt to uninstall wine I ran the command sudo apt-get purge wine* which as you may have guessed removed many of the default packages. I am wondering if there is a way to use the installation disk to reinstall the default packages without overwriting the file system. Not sure if it makes a difference or not, but I am duel booting Windows 8 and Ubuntu 14.04 which was updated from Ubuntu 12.04.  Thanks in advance. How does one prove that addition on $\mathbb{R}$ is associative? \includegraphics optional argument not resolved if macro Beamer - place text of footnote in footline I must place footnotes and footcites at the bottom of the frames, like shown in the picture:   The line above the footnotes must always be there, and it must have a minimum distance to the bottom of lets say 2.5em.  So I see two possible solutions:   Add the footnote via \setbeamertemplate to the footline. Change the format of the footnoteline and let it always appear, even if no footnote was used.   For the last hours, I tried to accomplish point 1, but I had absolutely no success. Can you please help me? Otherwise I have to use *whisper* Powerpoint. ;)    EDIT: Do you know the phenomenon that only after you ask someone, you can get the right ideas? ;)  Here is a MWE of my current solution:  \documentclass[xcolor={dvipsnames}]{beamer}  \usepackage[absolute, overlay]{textpos} \usepackage{environ}   \usetheme{default} \setbeamertemplate{navigation symbols}{}%remove navigation symbols   \newcommand{\makemyrule}{%     \setlength{\unitlength}{14pt}%      minimum distance to bottom     \ifdim\footnoteheight&gt;\unitlength \setlength{\unitlength}{\footnoteheight} \fi%     check which distance is bigger     \begin{textblock*}{\linewidth}(0pt,\dimexpr\textheight-\unitlength)%    place with use of textpos         \textcolor{blue}{\rule{\paperwidth}{.3ex}}     \end{textblock*} }   \let\oldfootnote\footnote%      redefine the footnote command \renewcommand{\footnote}[1]{\Addheight{#1}\oldfootnote{#1}}  \newlength{\footnoteheight} \newsavebox{\mytext} \newcommand{\Addheight}[1]%     measure height of the text         {%                 \savebox{\mytext}{\small\strut\parbox{\textwidth}%                 {\hspace*{2em}\thefootnote#1}\strut}%       approximated by eye, not perfect!                 \addtolength{\footnoteheight}{\ht\mytext}%                 \addtolength{\footnoteheight}{\dp\mytext}%         }     \NewEnviron{myframe}[1]{%     \begin{frame}{#1}%     \setlength{\footnoteheight}{0pt}%     \BODY%     \makemyrule%     \end{frame}%     }    \renewcommand\footnoterule{}  \begin{document} \begin{myframe}{} \frametitle{Beamer example} using\footnote{Y LUSPIN, et al} footnotes\footnote{P. GHOSEZ, et al and a lot more information to create a linebreak} excessively \footnote{You do not need to read this, this is only blindtext to create even more and more text. Blindtext will go on forever, nobody can stop the allmighty blindtext. I think I am a blindtext author.} \end{myframe}{} \begin{myframe} \frametitle{Beamer example} using\footnote{Y LUSPIN, et al} footnotes\footnote{P. GHOSEZ, et al} \end{myframe}{} \begin{myframe} \frametitle{Another example} without footnotes\\ \end{myframe} \end{document}   What this does: At the beginning of each myframe-environment, the length \footnoteheight is reseted to zero. When a \footnote is placed, the height of the text is added to this length. At the end of each frame, via \makemyrule the bottom rule is created, which is above the footnote texts (my solution is not perfect) or, if there are no footnotes, at least 14pt above the bottom.  My wishes (not real problems, but I want it to work better) are   The height of the footnotetext is only approximated. I would like a solution where you can measure the height of the formatted footnote. The frame environment needs to be renamed to myframe. I would like a solution which works without changing the document. But it all failed, because I could not execute \makemyrule before \end{frame} automatically. Quotient ring of Gaussian integers Divisibility tests and remainder mod $9,11,99,101,999,1001\,$ (casting out nines and elevens) Now I have proved the following two problems:      (1) Prove that a number and the sum of its digits have the same remainder upon division by 9.    (2) Given an integer, consider the difference between the sum of the digits in odd positions (counting from the right) and those in even positions. Show that the difference has the same remainder as the number itself when divided by 11.    Then, I need help on the following problem:      Partition the digits of a number into groups of two and three, respectively, starting from the right. Treat these as two- and three-digit numbers, respectively, and proceed similarly as in the two problems above. What divisibility rules arise?    In fact, I did not quite get what this problem asks for and not clear about this process. Could anyone give me some hints on this, please?  Thanks in advance. How can I make a div not larger than its contents? I believe that umask is something that controls , but do not fully understand it.  After running umask 0644 in a , I cannot read the files I create with the command-line text editor nano. I noticed that the permissions of that file are set to 0022 instead of the default 0755.  How does umask work? I thought I could just remove the each digit in the umask from 0777, 7 - 6 = 1 and 7 - 4 = 3, so I expect the permissions to be 0133, but apparently, this is not the case.   What is umask exactly? Explain it to me like I was a "Linux noob" How do I calculate with umask? What are use cases for umask? resizable serial console window? I would like to ask a question about Java that doesn't have a specific answer. It's a question to see what people think and to share their opinion.    Will Stack Overflow tolerate this, or is there another Stack Exchange resource where I may ask a question like this? Add an Image Upload button to the Mobile Site With the release of iOS 6, the most commonly used mobile browser now supports standard generic image upload buttons. This is actually really handy.  I can take screenshots on my phone or iPad, and use them to answer questions about apps made to run on those devices (or ) to answer questions. Until the release of iOS 6 however, the only way to use these images in my answer was to either sync them over to my computer, and then answer from a desktop, or use a specialized app to upload the images, such as PicUp or DropBox, and then manually write out the markdown code.  After iOS 6, the Image Upload button works just fine, if I switch to viewing the full site from my iDevice, rather than the mobile view. I can upload images directly, and the markdown is handled for me. It's awesome, except for the fact that the non-mobile site is decidedly non-awesome on the small screen of my phone.  Which brings me to my feature request: Add the Image Upload button (and other markdown shortcuts, as deemed worthwhile) to the ask/answer editors on the mobile version of SE sites. Stripped out bottom bracket The bottom bracket of my bike was completely stripped to the point that when you push the left side crank arm, the right crank moves and you can see the bottom bracket lock move out the frame. The bike shop tried putting Teflon tape but it's temporary. It's a 26' xc hard tail. For all I know both sides of the bottom bracket(square tapered) are stripped clean hence the Teflon tape put by the previous owner. Can I fix the problem by changing into a hallow tech cranks because it works like a thread less bb, or should I just buy a thread less square tapered bb? Any suggestion on what to do? Prove $X$ is compact iff for each family $\{ F_\alpha\}_{\alpha\in I}$ of closed subsets of $X$ with the FIP, we have $\cap F_\alpha\neq\varnothing$. I'm reading Intro to Topology from Mendelson.  The entire problem statement is,  Prove that $X$ is compact if and only if for each family $\lbrace F_\alpha\rbrace_{\alpha\in I}$ of closed subsets of $X$ that has the finite intersection property, we have $\bigcap_{\alpha\in I} F_\alpha\neq\varnothing$.  My attempt at the proof is as follows:  First assume that $X$ is compact. For the sake of contradiction, suppose that there exists a family $\{ F_\alpha\}_{\alpha\in I}$ of closed subsets of $X$ with FIP such that $\bigcap_{\alpha\in I} F_\alpha=\varnothing$. Since $X$ is compact if $\lbrace F_\alpha\rbrace_{\alpha\in I}$ any family of closed sets such that $\bigcap_{\alpha\in I} F_\alpha=\varnothing$, then there exists a finite set of indices $\lbrace \alpha_1,\dots,\alpha_n\rbrace$ such that $\bigcap\limits_{i=1}^n F_{\alpha_i}=\varnothing$. Yet, since $\lbrace F_\alpha\rbrace_{\alpha\in I}$ has the finite intersection property, for every finite index of $J\subset I$, $\bigcap\limits_{\alpha\in I} F_\alpha\neq\varnothing$.  Suppose now that $X$ is not compact, that is, there exists an open cover $\lbrace U_\alpha\rbrace_{\alpha\in I}$ of $X$ with no finite subcover. Consider the set $F_\alpha=C(U_\alpha).$ Then $\lbrace F_\alpha\rbrace_{\alpha\in I}$ is a collection of closed subsets of $X$ with the finite intersection property and were $\bigcap_{\alpha\in I} F_\alpha=\varnothing.$  Thanks for any feedback! I was reading a blogpost here:  () One thing that threw me off was that after the first four large displayed equations, there is the statement &quot;it is sufficient to prove that if the theorem holds for $n=m+1$, then it holds for $n=m$.&quot; How is this type of induction valid? I browsed around for things like backward induction, reverse induction, and Cauchy induction, but couldn't find a justification for how this is valid. With the usual forward induction of verifying a base case and proving $P(n)\implies P(n+1)$, it's easy to intuitively understand how induction will show a property holds for all natural numbers (or at least starting at the base case). But with this reverse induction, it seems to me that if you prove $P(m+1)\implies P(m)$, then if you were able to verify a specific case like $P(15)$, then you would only know it's true for numbers up to $15$. How does it actually prove the property for all naturals? Purpose: Construct a 95% confidence interval for $\theta$.   A common strategy is to construct a confidence interval for $\log(\theta)$ and then exponentiate.  Why is it valid?   My concern is that $E(\log(\theta)) \neq \log(E(\theta))$ and $Var(\log(\theta)) \neq \log(Var(\theta))$...   Do people use this back transformation because it has proven to work fine? What about other transformations (e.g. logit)? Understanding relation between Quotient Space and $S^1$ There is this example at the Wikipedia article on Quotient spaces (QS):     Consider the set $X = \mathbb{R}$ of all real numbers with the ordinary topology, and write $x \sim y$ if and only if $x−y$ is an integer. Then the quotient space $X/\sim$ is homeomorphic to the unit circle $S^1$ via the homeomorphism which sends the equivalence class of $x$ to $\exp(2πix)$.   I understand relations, equivalence relation and equivalence class but quotient space is still too abstract for me. This seems like a simple enough example to begin with.  I understand (sort of) the definition but I can't visualize. And by this example and others, there is a lot of visualizing going on here! torus, circles etc. A guy scammed me, but he gave me a bank account number & routing number. Can I use that to take out what he owes me? How can I use JUnit4 idiomatically to test that some code throws an exception?  While I can certainly do something like this:  @Test public void testFooThrowsIndexOutOfBoundsException() {   boolean thrown = false;    try {     foo.doStuff();   } catch (IndexOutOfBoundsException e) {     thrown = true;   }    assertTrue(thrown); }   I recall that there is an annotation or an Assert.xyz or something that is far less kludgy and far more in-the-spirit of JUnit for these sorts of situations. There is a kind of situation that seems to occur somewhat commonly, that goes something like:   Figure out some way to handle a particular situation do it regularly, and make a habit of it, as it seems to work OK … … and only much later actually realize that it very much isn’t OK, that it’s been doing harm all the time, and that it’s too late to fix anything.   Does there exist any good words or phrases for this kind of situation? Tuning PostGIS for production environments? What PostGIS documentation have you come across that has been helpful when tuning PostGIS for a production environment?  I would like to get together with my DBA to setup a Postgresql/PostGIS installation that is fit for production. I have read that there is some tweaking involved to achieve this, and I was hoping to find the answer on the .  So far I have found some documents on the OpenGeo site helpful, .  And this  is the kind of information I have found helpful, this is probably just basic DB stuff but to me its good stuff.  I would be interested to see what resources have helped others in achieving a stable production installation of PostGIS.