Using putty, by mistake, I've used this command to change the folder permission /etc:  sudo chown -R ec2-user:ec2-user /etc   Now when I'm trying to restart my Apache server the result is:  $ sudo service httpd restart  sudo: /etc/sudo.conf is owned by uid 500, should be 0 sudo: /etc/sudoers is owned by uid 500, should be 0 sudo: no valid sudoers sources found, quitting sudo: unable to initialize policy plugin   How to recover of this situation? I don't have physical access, but I have WinSCP and I can change permission directly.
I accidently ran  sudo chmod 755 -R /   instead of  sudo chmod 755 -R ./   I stopped it after few seconds, but now there is some problems such as  sudo: must be setuid root   How can I revert permissions back?
What does (obj.length === +obj.length) compare? How was the torque-force relationship discovered I get this error in the deployment step of a share-point farm based project. Most of the suggested solutions on the net are a simple Visual Studio re-start, however, a simple VS restart won't fix this.   Any ideas on what might be causing this? Saying that refers to not going overboard in solving a problem when a simple solution exists So I know I've heard this saying in American English before but I just can't quite find the original.  I have come up with several made up variations like:   I don't send the Navy (or whole army, or a battalion) when all you need is a diplomat. Don't buy the whole cow when all you need is milk.   What's the more commonly heard saying/phrase for this of expression? PHP expression <<<EOB Find & Delete duplicated files on multiple harddisks at once Quick-and-dirty way to ensure only one instance of a shell script is running at a time Sobolev inequality If $f\in H^2(\mathbb R^2)$, I want to show that    $||f||_{L^\infty}\le c||f||_{H^2}$ $||f||_{L^\infty}\le c||f||_{H^1} [1+\ln(1+||f||_{H^2})]$   For 1, I use $||f||_{L^\infty}\le \sup_{x\in \mathbb R^2} |f|\le\int_{\mathbb R^2} |\hat f(\xi)|d\xi = \int(1+|\xi|^2)^{-1}(1+|\xi|^2)|\hat f(\xi)|d\xi \le (\int (1+|\xi|^2)^{-2}d\xi)^2(\text {which is integrable in this case})||f||_{H^2}\to \text{is this correct?}$   But for 2, I am stucked. How can I get the "ln"? and how can I make it into a product of $H^1$ and $H^2$ norm? I know how to detect when resistors are arranged in parallel or series arrangement and I can also find their equivalent resistance in simple circuits or when resistances are connected in form of triangle but what happens when the arrangement is complex like this :   Which resistors are parallel and which are in series ? How can I find the equivalent resistance in such cases ? Is there rule or method for figuring this out ? How did Google find my unlinked newly created pages? I am building a new site, but creating the content using a subdirectory on an existing site. I have never posted a link to this subdirectory anywhere, yet searching Google reveals that Google has found these pages on my site and indexed them.  Further, I updated the site with a robots.txt file that WMT reports as being read, and testing the blocked pages using the WMT test tool indicates that the pages will not be indexed. Apparently this does not remove the pages from existing results, though I submitted a request to do so.  How did Google find these pages to begin with? Is it because I used a common subdirectory name and Google guesses at common subdirectories? Find missing indexes tool available to find missing indexes in mssql 2008 ? can we find the missing index using Database Engine Tuning Advisor In Minecraft, the NBT (Named Binary Tag) format is used to store data of our Minecraft worlds, including block, entity, and item properties. In the Java Edition of Minecraft, you can modify this data by including the data in the command, like so: /give @s diamond_sword{Enchantments:[{id:&quot;minecraft:knockback&quot;,lvl:10s}]}  In the Bedrock Edition, on the other hand, NBT is inaccessible from commands. In order to modify NBT, we need to use an external editor. What are some useful item properties that I can modify with an NBT editor, and how can I do so?  Related: How to access HTML element without ID? For instance in the snippet below - how do I access the h1 element knowing the ID of parent element (header-inner div)?  &lt;div id='header-inner'&gt;     &lt;div class='titlewrapper'&gt;        &lt;h1 class='title'&gt;        Some text I want to change       &lt;/h1&gt;     &lt;/div&gt;  &lt;/div&gt;   Thanks! Properties of $\liminf$ and $\limsup$ of sum of sequences: $\limsup s_n + \liminf t_n \leq \limsup (s_n + t_n) \leq \limsup s_n + \limsup t_n$ Let $\{s_n\}$ and $\{t_n\}$ be sequences.  I've noticed this inequality in a few analysis textbooks that I have come across, so I've started to think this can't be a typo:  $\limsup\limits_{n \rightarrow \infty} s_n + \liminf\limits_{n \rightarrow \infty} t_n \leq \limsup\limits_{n \rightarrow \infty} (s_n + t_n) \leq \limsup\limits_{n \rightarrow \infty} s_n + \limsup\limits_{n \rightarrow \infty} t_n$.  I understand the right two-thirds of the equation, and can prove it.  I'm stuck on the far-left third.  I don't understand how that is true. How to delete files listed in a text file Best way to detect when a user leaves a web page? What is the best way to detect if a user leaves a web page?  The onunload JavaScript event doesn't work every time (the HTTP request takes longer than the time required to terminate the browser).  Creating one will probably be blocked by current browsers. How to enable exFAT in Ubuntu 14.04 Auto Increment Problem in Mysql $ a+b+c+d=6 , a^2+b^2+c^2+d^2=12$ $\implies$ $ 36 \leq 4(a^3+b^3+c^3+d^3)-(a^4+b^4+c^4+d^4) \leq48 $ Let $a , b, c, d$ be real numbers such that $$ a+b+c+d=6 \\ a^2+b^2+c^2+d^2=12$$  How do we prove that $$ 36 \space \leq\space 4(a^3+b^3+c^3+d^3)-(a^4+b^4+c^4+d^4) \space\leq48\space$$ ? Help finding a combinatorial proof of $k {n \choose k } = n {n - 1 \choose k -1}$ Help finding a combinatorial proof of $k {n \choose k } = n {n - 1 \choose k -1}$  I have expanded it this far:  $$\frac{k \cdot n!}{k!(n-k)!} = \frac{n \cdot (n-1)!}{(k-1)!(n-k)!} $$  but then I am stuck from where to go from there.