Wifi doesn't work in Ubuntu 15.10 - Realtek RTL8723BE/RTL8188EE 802.11b/g/n Wireless LAN Drivers
Realtek RTL8723BE Wi-Fi incredibly weak
number of trailing zeros How do I add permissions via command line for "everyone" on external HDD I have an external HDD and I kind of messed up the file permissions but when fixing it I thought it is ok bc with my username I can access the files perfectly fine. Now that I use this with two PC (actually ATM I don't have access to my other PC) I can't access these files.  The problem is this directory has hundreds of folders with no permission for "everyone". I would like to give it the default permissions including have all access for the user "everyone". How do I do that via command line for these hundreds of folders? Isomorphism between $\mathfrak o(4,\mathbb R)$ and $\mathfrak o (3,\mathbb R) \oplus\mathfrak o (3,\mathbb R) $ I see an equation like this:  $$y\frac{\textrm{d}y}{\textrm{d}x} = e^x$$  and solve it by "separating variables" like this:  $$y\textrm{d}y = e^x\textrm{d}x$$ $$\int y\textrm{d}y = \int e^x\textrm{d}x$$ $$y^2/2  = e^x + c$$  What am I doing when I solve an equation this way?  Because $\textrm{d}y/\textrm{d}x$ actually means  $$\lim_{\Delta x \to 0} \frac{\Delta y}{\Delta x}$$  they are not really separate entities I can multiply around algebraically.    I can check the solution when I'm done this procedure, and I've never run into problems with it.  Nonetheless, what is the justification behind it?  What I thought of to do in this particular case is write  $$\int y \frac{\textrm{d}y}{\textrm{d}x}\textrm{d}x = \int e^x\textrm{d}x$$ $$\int \frac{\textrm{d}}{\textrm{d}x}(y^2/2)\textrm{d}x = e^x + c$$  then by the fundamental theorem of calculus  $$y^2/2 = e^x + c$$  Is this correct?  Will such a procedure work every time I can find a way to separate variables? Fiber from $S^1$ to $\mathbb{R} P^1$ that does not admit a section. Consider the map $q:S^1 \to \mathbb{R} P^1$ given by $v \mapsto \mathbb{R} v$. I want to show that this map does not admit sections. I've previously shown that $S^1$ is diffeomorphic to $\mathbb{R} P^1$ but this doesnt seem to be of much help. I've also shown that $TS^1$ is trivial, however I don't see how to use this. My only idea is that such a section wouldn't be well defined since it could go to either antipidal points when composing with $q$. Any hint or help with this would be amazing! Splitting string into pair of characters in Ruby For a certain Hibernate entity we have a requirement to store its creation time and the last time it was updated.  How would you design this?   What data types would you use in the database (assuming MySQL, possibly in a different timezone that the JVM)?  Will the data types be timezone-aware? What data types would you use in Java (Date, Calendar, long, ...)? Whom would you make responsible for setting the timestamps&mdash;the database, the ORM framework (Hibernate), or the application programmer? What annotations would you use for the mapping (e.g. @Temporal)?   I'm not only looking for a working solution, but for a safe and well-designed solution. Is there any mention of the lands east of Mordor? Sauron seems to have huge armies east of Mordor, the Blue Wizards went there and didn't come back, and early maps of Arda when it was still flat show rough landmarks, but not much, and everything changed after the Second Age.  Is there any canonical information about the East? The context for my question might be a bit strange.   I have stuttering and therefore I have some difficulties pronouncing some words starting with particular phonetics. And I've found that if a sentence starts with a /th/ sound, it makes me feel uncomfortable.  Especially in the word is "thanks" or "thank you".  So I want to know if there's a popular alternative for "thank you" that may not seem strange and that unnatural. I've searched the website and I know there are alternatives like "I appreciate your help." but that sounds a bit overly formal for me. (Or is it? correct me if I'm mistaken.) Number of Homomorphisms from $\Bbb{Z}_m$ to $\Bbb{Z}_n$ This question coutesy of Allan Clark's "Elements of Abstract Algebra" (60$\zeta$).   Find the number of homomorphisms from $\Bbb{Z}_m\to \Bbb{Z}_n$ as a function of $m$ and $n$.  This is stumping me, can anyone help? for loop wget directory creation error As a Ubuntu beginner. I am trying to download links from multiple text files with wget2 in batch. The -P &quot;$f&quot; creates directory name with .txt suffix. Is it possible to ignore .txt for -P &quot;$f&quot;. Any modification suggestions. for f in *.txt;do wget2 -i &quot;$f&quot; -P &quot;$f&quot;;done Prove $\sqrt{2}$ is between $\dfrac{a}{b}$ and $\dfrac{a+2b}{a+b}$ Let $a$ and $b$ be positive integers. Show that $\sqrt{2}$ always lies between $\dfrac{a}{b}$ and $\dfrac{a+2b}{a+b}$.  Please give the easy solution as possible. Currently, a user does not get any notification when a trivial edit (less than 6 characters, by a user who has the ) is made on one of his/her posts. As in .  Even though the user is trust-worthy (owing to the rep of the user), wouldn't it be nice for the OP to get a notification whenever an edit is made, even trivial? What is the cardinality of the set of all topologies on $\mathbb{R}$? This was  on Quora. I thought about it a little bit but didn't make much progress beyond some obvious upper and lower bounds. The answer probably depends on AC and perhaps also GCH or other axioms. A quick search also failed to provide answers. Control Android with broken screen from PC How do I find the address of last non-blank cell in a row (while skipping columns) I understand that the letter "J" is relatively new — perhaps 400–500 years old.  But since there has long been important names that begin with J, such as Jesus, Joshua, Justinian, etc., and which predate the introduction of a special letter, does that mean that the "J" sound predated the letter, or were such famous names spelled and pronounced differently? What is a smart pointer and when should I use one? Build and strengthen the Stack Exchange community with "crossover questions" between sites The computer gave me this output in a window:  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages E: The package lists or status file could not be parsed or opened.   How can I fix this?