Have a look at this screenshot:    $ mkdir someDir $ cd someDir $ ls -l total 0 $ touch someFile $ ls -l total 8 -rw-rw-r-- 1 user user 0 Nov 5 01:29 someFile   Pardon for my language used when I installed Ubuntu. Anyways, it is beyond my imagination how come creating an empty file actually creates eight files, alas, the extra seven won't be listed more than have their saying in the statistics. The total column clearly says eight. I'm using Ubuntu 12.10 x86. Also, in my Nautilus file explorer, I have checked the option to view hidden and system files. Maneuvering to the new someDir directory won't show more than just one file, the someFile file. So is the total count lying in my face or are there even more hidden files than the "ordinary" hidden files? I'm keen to know exactly what files gets created here, why so, and how come I can't list them.  As a side note, adding the sudo prefix to the ls -l command won't make any difference for me.  Thank you so much in advance.
Apparently I cannot count. I think there are three files in /media  $ tree /media /media ├── foo ├── onex └── zanna 3 directories, 0 files   However, ls -l finds 12.  $ ls -l /media total 12 drwxr-xr-x  2 root root 4096 Jul 31 20:57 foo drwxrwxr-x  2 root root 4096 Jun 26 06:36 onex drwxr-x---+ 2 root root 4096 Aug  7 21:17 zanna   And, if I do ls -la I get only . and .. in addition to the above, but the count is total 20  What's the explanation?
I'm trying to migrate a MySQL-based app over to Microsoft SQL Server 2005 (not by choice, but that's life).  In the original app, we used almost entirely ANSI-SQL compliant statements, with one significant exception -- we used MySQL's group_concat function fairly frequently.  group_concat, by the way, does this: given a table of, say, employee names and projects...  SELECT empName, projID FROM project_members;   returns:  ANDY   |  A100 ANDY   |  B391 ANDY   |  X010 TOM    |  A100 TOM    |  A510   ... and here's what you get with group_concat:  SELECT      empName, group_concat(projID SEPARATOR ' / ')  FROM      project_members  GROUP BY      empName;   returns:  ANDY   |  A100 / B391 / X010 TOM    |  A100 / A510   So what I'd like to know is: Is it possible to write, say, a user-defined function in SQL Server which emulates the functionality of group_concat?   I have almost no experience using UDFs, stored procedures, or anything like that, just straight-up SQL, so please err on the side of too much explanation :) Let $p$,$\ q$ be prime numbers and $n\in \mathbb{N}$ such that $p \nmid n-1$. If $p \mid n^q-1$, then $q \mid p-1$. Why is $\sqrt{-x}*\sqrt{-x}=-x?$ Why is $\frac{1}{\infty } \approx 0 $ and $ \frac{1}{0} = {\infty}$? First I have checked the search option but found nothing relevant to my problem and also level of math. I just started learning the language of mathematics, on my own and I have trouble understanding why  $  \frac{1}{\infty } \approx 0 $ and  why $\frac{1}{0} = {\infty}$?  I want to know how exactly do I get to these answers. It might sound strange but it's hard for me as a beginner to picture things like this on my own. Meaning of $\int\mathop{}\!\mathrm{d}^4x$ What the following formula mean?  $$\int\mathop{}\!\mathrm{d}^4x$$  I know that this $\int f(x)\mathop{}\!\mathrm{d}x$ is the integral of the function $f$ over the $x$ variable, but the following $\int\mathop{}\!\mathrm{d}^4x$ leave empty the argument and also have the $\mathrm{d}$ elevated to the fourth power. What that mean?  Update.  In the Einstein-Hilbert action we have (note that I have understand that the other parts of the integral are relevant only after your answers, thus sorry.):  $$S=\frac{c^4}{16\pi G}\int\mathop{}\!\mathrm{d}^4x \, \ R \sqrt{-g}$$ Cannot detect wireless driver intel ac wireless 9560 [logs included] Currently using Ubuntu 18.04, and my wireless driver is not being detected.  I've included a .  $ dmesg | grep iwl [    6.212724] Loading modules backported from iwlwifi [    6.212724] iwlwifi-stack-public:master:6988:0d8892f2 [    6.224583] iwlwifi 0000:00:14.3: enabling device (0000 -&gt; 0002) [    6.229811] iwlwifi 0000:00:14.3: Direct firmware load for iwl-dbg-cfg.ini failed with error -2 [    6.230540] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-39.ucode failed with error -2 [    6.230547] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-38.ucode failed with error -2 [    6.230552] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-37.ucode failed with error -2 [    6.230557] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-36.ucode failed with error -2 [    6.230562] iwlwifi 0000:00:14.3: Direct firmware load for iwlwifi-9000-pu-b0-jf-b0-35.ucode failed with error -2 [    6.236670] iwlwifi 0000:00:14.3: loaded firmware version 34.0.0 op_mode iwlmvm [    6.248314] iwlwifi 0000:00:14.3: Detected Intel(R) Dual Band Wireless AC 9560, REV=0x318 [    7.264081] iwlwifi 0000:00:14.3: SecBoot CPU1 Status: 0x3, CPU2 Status: 0x2477 [    7.264084] iwlwifi 0000:00:14.3: Failed to start INIT ucode: -110 [    7.276165] iwlwifi 0000:00:14.3: Failed to run INIT ucode: -110   sudo modprobe iwlwifi returns no output. How do I install drivers for Realtek RTL8812BU? So I've been experimenting with Ubuntu on and off for a while, but I honestly have no idea what the hell I'm doing. So I have a realtek RTL8812bu WiFi dongle that I'm hoping to get working. I did some research, and came across  that a couple people across two threads said worked for them:  At the bottom it said there is a new version . So somewhere it said it was confirmed to work on kernels up to 4.16, so I checked and I'm on 4.15.0. But the problem I'm having, is what am I supposed to do? There is some installation guide at the bottom that is about as clear as mud to me since I don't know much. Do cards with abilities that target trigger heroic? Archimedes' principle for two liquid layers Problem: I have a cylindrical vessel of height $H$ and radius $R$. There are two liquid layers in the vessel. The first has density $D_1$ and height $h_1$, the second has density $D_2$ and height $h_2$. The second liquid is floating on the first liquid (thus $D_2 &lt; D_1$) and they are both entirely within the vessel ($h_1+h_2 \le H$). Now I have a cube of density $D$ and edge length $n$. The cube fits into the vessel ($n \le \sqrt2R$) but it might not be completely inside it ($n&gt;H$ is possible). I place it into the vessel such that one side is horizontal (the cube is not lopsided). Some liquid might overflow as a result. How do I use Archimedes' principle to calculate the topmost liquid level after placing the cube? I can ignore damping and other physical effects. EDIT: Note that the only values I know are $H, R, D_1, h_1, D_2, h_2, n$ and their abovementioned constraints.  My workings: I tried using the formula directly, where $\text{weight of cube}=\text{weight of displaced liquid}$. I first get $Dn^3=D_2n^2s_2$ where $s_2$ is the height submerged in the second liquid. If $s_2 \le h_2$ then the cube is only submerged in the second liquid. So the answer is $\min(H, h_1+h_2+{n^2s_2\over\pi R^2})$, accounting for overflows. This case is simple. But if $s_2&gt;h_2$ then the cube can be submerged in the first liquid too. I thought of subtracting the weight of the second liquid displaced to obtain the height submerged in first liquid, but realize that I don't know that. The weight displaced depends on the final liquid height, which can be affected by overflows, whether the cube fits totally within the two liquids, etc. In fact, it can be the case that after the liquid level rises, the cube now displaces more of the second liquid, causing it to not be submerged in the first (is that even possible?) It seems very messy and I have no idea how to start. :( Does anyone have a nice solution to this problem? Can't boot XP after Ubuntu Installation, how to fix? I installed Ubuntu and after the installation, i can't boot to XP. When i choose XP from the Grub menu, I got black screen for like 30 sec, and then it returns to the Grub menu.  Thanks! bash: syntax error near unexpected token `}' I've been looking for this feature in Blender, either upon the time of creation using Edge Cut and Slide or afterwards, in just editing the mesh. I'd like to know if it's possible to evenly slide two edges away from one another in Blender?  Here's a picture of what I'd like to be able to do:    Thanks upfront!! How to adjust the gap between figure and caption within the same subfloat My question is:  How to adjust the gap between figure and caption within the same subfloat  Not the gap between two subfloat.  For the following example:  \begin{figure}     \centering     \subfloat[A]{\includegraphics[ scale=0.5]{images/a.jpg}}     \vspace{-10pt}     \subfloat[B]{\includegraphics[scale=0.5]{images/b.jpg}}     \vspace{-10pt}     \caption{}\label{fig:online_test} \end{figure}   I got the following figure:    The sub-caption of (a) is too close to the sub-figure B. I hope the caption (a) to stay closer to sub-figure A. How can I adjust the space between the caption and figure within a subfloat?  Thank you all for helping me and I would prefer a solution for subfloat, instead of using other packages. But I would also appreciate a solution of using other packages.   I know my question looks similar to . But please make it clear. I'm asking for how to adjust the gap between figure and caption within a subfloat, not the gap between two subfloat. That is, the gap between the caption "a" and the figure "A"  Thank you. How to create posters using LaTeX How to keep leading zeros in PHP integer Casting nines and elevens in other bases (radix) and doing check sums for binary How to prevent automatic redirection of 404 errors and "incorrect" URLs? Wordpress has a feature whereby it will automatically redirect your URLs if it percieves them to be written wrongly. Here is an example: I have a page called my-page  If I go to:  www.mysite.com/something/my-page/   it will immediately redirect me to   www.mysite.com/my-page/   as nothing exists at the first URL.   How can I turn this feature off, and instead just get a 404 if incorrect URL's are typed in? Is there any reason to not complete the game? Would there be anything in Skyrim where you wouldn't want to complete the main story? (Yes, I know the game continues after that)  Like something you can no longer access, or do after beating the game? I am having trouble getting onto a server in Minecraft PE on iOS. When I tap on the person's server it just says invalid name:    I have tried turning off and restarting the iPad, going to home screen and logging back into the server but I have had no luck and no change. Is there a reason why this is so? If I don't want to set any special behavior, is it OK if I don't bother to have a robots.txt file?