I want to build a Linux system from scratch, and i want the most basic Ubuntu package. If possible only the command line and that's it. What should i download for it?
I keep having to re-install Ubuntu after trying advice.  This is very frustrating.  All I want is to boot to a Linux command prompt.  Please help!
How to compute $$\sqrt{(1\sqrt{(2\sqrt{(3\dots)})})}$$ &amp; $$\sqrt{(1+\sqrt{(2+\sqrt{(3+\cdots)})})}$$?  I understand that  $$\sqrt{(1\sqrt{(2\sqrt{(3\dots)})})}=(1^{1/2})(2^{1/4})(3^{1/8})\cdots$$  and  $$\sqrt{(1+\sqrt{(2+\sqrt{(3+\cdots)})})}=(1+(2+(3+(\cdots))^{1/8})^{1/4})^{1/2} $$  How to Proceed further? How to escape braces (curly brackets) in a format string in .NET How can brackets be escaped in using string.Format? For example: String val = &quot;1,2,3&quot; String.Format(&quot; foo {{0}}&quot;, val);  This example doesn't throw an exception, but it outputs the string foo {0}. Is there a way to escape the brackets? What is the regular expression to match strings (in this case, file names) that start with 'Run' and have a filename extension of '.py'?  The regular expression should match any of the following:  RunFoo.py RunBar.py Run42.py   It should not match:  myRunFoo.py RunBar.py1 Run42.txt   The SQL equivalent of what I am looking for is ... LIKE 'Run%.py' .... How to extract img src, title and alt from html using php? I would like to create a page where all images which reside on my website are listed with title and alternative representation.  I already wrote me a little program to find and load all HTML files, but now I am stuck at how to extract src, title and alt from this HTML:  &lt;img src="/image/fluffybunny.jpg" title="Harvey the bunny" alt="a cute little fluffy bunny" />  I guess this should be done with some regex, but since the order of the tags may vary, and I need all of them, I don't really know how to parse this in an elegant way (I could do it the hard char by char way, but that's painful). How to load up CSS files using Javascript? Is it possible to import css stylesheets into a html page using Javascript? If so, how can it be done?  P.S the javascript will be hosted on my site, but I want users to be able to put in the &lt;head&gt; tag of their website, and it should be able to import a css file hosted on my server into the current web page. (both the css file and the javascript file will be hosted on my server). Label rows of a matrix by characters LaTeX package "titling", titles with hard line breaks, and \MakeUpperCase I have a document with a title that is spread over several lines using hard line breaks. To configure the title formatting, I use the titling package with code adapted from its documentation:  \documentclass{article}  \usepackage{titling} \pretitle{\begin{center}\LARGE\sffamily\bfseries} \posttitle{\par\end{center}\vskip 0.5em}  \title{Higgelty Pigglety Pop! \\ or \\ There Must Be More to Life}  \begin{document} \maketitle \end{document}   …and it works perfectly.  I now want the title additionally to be in all caps and therefore change the \pretitle command:  \pretitle{\begin{center}\LARGE\sffamily\bfseries\MakeUppercase}   …and I get the following error message:  ! Use of \@icentercr doesn't match its definition. &lt;argument&gt; \def  l.12 \maketitle   This only happens with a title that includes hard line breaks.  What does this error message mean? How can I fix it? I read (or do I say "have read"?) many rules for when to use the present perfect. I found them complex and hard to understand (or do I say "have found"?). I am finding it hard to apply these rules in real sentences.  Is there a simple and clear way to explain the difference between past simple and present perfect? If there is a simple explanation, please tell it! If there is no simple explanation, please tell why it is so complicated. Maybe if I knew why there is no simple explanation, that would help me understand what work I need to do in order to learn the difference. How do I make a bootable USB from Windows? Marker shadows in Google Maps v3 Shell script works when saved with nano but not when saved with Notepad++ When I copy my bash script across from Notepad++ into a new file with nano editor inside SSH and save. It runs fine. (sh ./install).   But if I save the file (Exact same contents), upload to my web server, download it using Wget on the same machine. I get syntax errors. I've checked the encoding and they seem to be the same. I have since used a plethora of character encoding to see if it will resolve the issue. I am also setting the file to executable once I download it using wget!  The file runs fine and I have zero errors when copy and pasting using nano. Any idea what this may be? I faced this issue when I want to use sudo command :  sudo: /etc/sudoers is owned by uid 1000, should be 0 sudo: no valid sudoers sources found, quitting sudo: unable to initialize policy plugin   then I tried a solution from a similar question in order to change the owner back to the root:   $ pkexec visudo   also I tried this one   $ pkexec chown root:root /etc/sudoers /etc/sudoers.d -R   but I have faced another issue with these commands:   Error getting authority: Error initializing authority: Could not connect: No such file or directory   So is there a solution to this issue?    Full shell issue snippets:   ubuntu@LAPTOP-D4T16P7J:~$ sudo -i sudo: /etc/sudoers is owned by uid 1000, should be 0 sudo: no valid sudoers sources found, quitting sudo: unable to initialize policy plugin ubuntu@LAPTOP-D4T16P7J:~$ pkexec visudo Error getting authority: Error initializing authority: Could not connect: No such file or directory ubuntu@LAPTOP-D4T16P7J:~$ pkexec chown root:root /etc/sudoers /etc/sudoers.d -R Error getting authority: Error initializing authority: Could not connect: No such file or directory     This is my /etc/sudoers file:   ubuntu@LAPTOP-D4T16P7J:~$ cat /etc/sudoers # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults        env_reset Defaults        mail_badpass Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL  # See sudoers(5) for more information on "#include" directives:  #includedir /etc/sudoers.d     OS info:    Ubuntu WSL2. What free/open source image design programs can you recommend? Are there any free/ open source image designing programs that you can recommend? Proving that the Hopf map $S^3 \to S^2$ is a submersion I need to show that the Hopf map $H : S^3 \to S^2$ is a submersion. There are many ways to define it, but for now I've gone with the restriction of the function $F : \mathbb{R}^4 \to \mathbb{R}^3$ mapping $$(x,y,u,v)\mapsto (2(xu+yv), 2(xv-yu), x^2+y^2-u^2-v^2).$$ It wasn't too bad to show that $F$ is a submersion, but is there a way to go from here to show that $H$ is a submersion? I can write down $H$ as the composition $$S^3 \overset{\iota}{\hookrightarrow} \mathbb{R}^4 \overset{F}{\to} \mathbb{R}^3 \overset{\pi}{\to} S^2,$$ and define $\pi(p) = p/\lVert p\rVert$, but I don't really know where to go after computing the Jacobian of $\pi$, and I don't know if this will even work for my purposes (I don't see how to argue that the composition of the corresponding differentials here isn't rank $1$ — I know $d\iota$ has trivial kernel but things seem to break down once I get to $d\pi$). I'm really just trying to avoid having to compute the Jacobian of $H$ with respect to the stereographic projections and show that that beast of a thing is full rank. Am I on the right track, or is there a better way? Should I delete my own questions with answers? I don't know much about this,  But I've some of the questions on which some user has answered (not helpful answer) also but I want to delete those questions, but whenever I go to delete that question. It is prompting with     What does it mean? Can someone tell me what would be the action taken by Stack Exchange if I delete more questions? Hash join between master/detail tables produces too-low cardinality estimate CSS Display an Image Resized and Cropped I want to show an image from an URL with a certain width and height even if it has a different size ratio.  So I want to resize (maintaining the ratio) and then cut the image to the size I want.  I can resize with html img property and I can cut with background-image.  How can I do both?  Example:  This image:     Has the size 800x600 pixels and I want to show like an image of 200x100 pixels   With img I can resize the image 200x150px:  &lt;img      style="width: 200px; height: 150px;"      src="http://i.stack.imgur.com/wPh0S.jpg"&gt;    That gives me this:    &lt;img style="width: 200px; height: 150px;" src="https://i.stack.imgur.com/wPh0S.jpg"&gt;       And with background-image I can cut the image 200x100 pixels.  &lt;div      style="background-image:            url('https://i.stack.imgur.com/wPh0S.jpg');      width:200px;      height:100px;      background-position:center;"&gt;&amp;nbsp;&lt;/div&gt;    Gives me:        &lt;div style="background-image:url('https://i.stack.imgur.com/wPh0S.jpg'); width:200px; height:100px; background-position:center;"&gt;&amp;nbsp;&lt;/div&gt;      How can I do both?  Resize the image and then cut it the size I want? How to use GeoPandas buffer function to get buffer zones in kilometers? Is "architect" a verb and a noun? I hear the word architect used as a verb in the technical field and now more often in other industries and groups, for example:     We need to architect a better solution to the problem.   I am interested if this is considered acceptable usage, as I see this word being used more in published technical documents (not necessarily books, but corporate publications).  I can see how a conductor can conduct, a typist can type, but can a scientist "science"?  A scientist might research, analyze, and so forth, as an architect might design, create, build, etc.  Merriam-Webster , however, I have been told that other dictionaries exist that define architect as both a noun and a verb&nbsp;— is there a credible reference or source that authoritatively answers this question? From this  on Bayesian Least Mean Square estimation:  $$\mathbf E\left[(\Theta -\hat\theta)^2\right] = \rm{var}(\Theta -\hat\theta) + \left(\mathbf E[\Theta -\hat\theta]\right)^2 = \rm{var}(\Theta) + \left(\mathbf E[\Theta -\hat\theta]\right)^2$$  which is to say that $\rm{var}(\Theta -\hat\theta) = \rm{var}(\Theta)$.  I would like to ask how that comes about?  Thanks.  $\Theta$ is the random variable being estimated, and $\hat\theta$ is a constant estimate.