I know this is kinda stupid thing but I had some issues in my mysql database, I fixed them but when I had to delete some folders I executed a command to delete this folder /etc/mysql I have a lot of important databases which disallows me to reinstall MySQL. Is there anything like any command that allows me to recover these files? Everything was in default format so I don't really care about like the old format. If so please reply to this topic with answer or even send me a .zip file contains all files with default format for the latest MySQL version (5.7).  Thanks. I use ubuntu 16.04 by the way.   EDIT: after processing what is showing here as someone linked this topic in comments  So now I have an issue with MySQL itself.   Here's the Error message:  Job for mysql.service failed because the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details. invoke-rc.d: initscript mysql, action "start" failed. ● mysql.service - MySQL Community Server    Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)    Active: activating (auto-restart) (Result: exit-code) since Sat 2019-12-21 16:59:38 EST; 5ms ago   Process: 3942 ExecStartPost=/usr/share/mysql/mysql-systemd-start post (code=exited, status=0/SUCCESS)   Process: 3941 ExecStart=/usr/sbin/mysqld (code=exited, status=2)   Process: 3933 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)  Main PID: 3941 (code=exited, status=2)  Dec 21 16:59:38 ns529730 systemd[1]: Failed to start MySQL Community Server. Dec 21 16:59:38 ns529730 systemd[1]: mysql.service: Unit entered failed state. Dec 21 16:59:38 ns529730 systemd[1]: mysql.service: Failed with result 'exit-code'. dpkg: error processing package mysql-server-5.7 (--configure):  subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing:  mysql-server-5.7 E: Sub-process /usr/bin/dpkg returned an error code (1)
I would like to restore LightDM to its default state, because for some reason /etc/lightdm/unity-greeter.conf is now an empty file.  Deleting /etc/lightdm/unity-greeter.conf and then running sudo apt-get install --reinstall unity-greeter doesn't create a new config file as you might expect.   How can I restore a missing config file?
How do I give myself an item that can only be placed on a block with a certain damage value? I'm currently in the process of making a custom map and I want to add blocks that can only be placed on a certain colour clay.  This is the command I tried using.  /give @p cobblestone 1 0 {CanPlaceOn:["hardened_stained_clay"],Damage:3}   However, even with this command the cobblestone can be placed on any colour of stained clay. What command can I use for placing only on a certain block? Prove that $ AB$ is a subgroup of order $mn$ if $m$ and $n$ are relatively prime. Let $A \in \mathbb{R}^{p \times p}$ and $B \in \mathbb{R}^{q \times q}$ be nonsymmetric positive definite matrices in the sense that $v^T A v &gt; 0, \forall v \in \mathbb{R}^p$ and $v^T B v &gt; 0, \forall v \in \mathbb{R}^q$.  I know that $A \oplus B$, i.e. a matrix with a block structure \begin{align} \pmatrix{A &amp; 0 \\          0 &amp; B} \end{align} is positive definite and I also know that if $p=q$, then $A+B$ is positive definite as well.  Can I say that as well if the blocks overlap partially? When?   For instance a matrix as follows: \begin{align} \pmatrix{a_{11} &amp; a_{12} &amp; a_{13} &amp; a_{14} &amp; 0&amp; 0\\          a_{21} &amp; a_{22} &amp; a_{23} &amp; a_{24}&amp; 0&amp; 0\\          a_{31} &amp; a_{32} &amp; a_{33} + b_{11} &amp; a_{34} + b_{12} &amp;b_{13}&amp;b_{14}\\          a_{41} &amp; a_{42} &amp; a_{43} + b_{21} &amp; a_{44} + b_{22} &amp;b_{23}&amp;b_{24}\\          0 &amp; 0 &amp; b_{31} &amp; b_{32} &amp;b_{33}&amp;b_{34} \\          0 &amp; 0 &amp; b_{41} &amp; b_{42} &amp;b_{43}&amp;b_{44}} \end{align} Someone is offering to pay me in a sort of sugar daddy/sugar baby arrangement. They want to make online deposits to me, and they're asking me for my online banking username and password. Is that information alone enough for them to be able to take my money out of my account, or am I safe? I have windows 7 in Arabic. Now I dowloaded QGIS 2.14.3-2 in French.  But when I installed it shows Arabic menu/tools...  How can I change the menu language to French? My book uses the argument that the multiplicities of a few macrostates in a macroscopic object take up an extraordinarily large share of all possible microstates, such that even over the entire lifetime of the universe, if each microstate had an equal chance of being accessed, fluctuations away from equilibrium would never occur.  My question to this statistical proof is this: In the real world, is there really an infinitesimal but nonzero chance that macroscopic systems could access some of the more unlikely macrostates (e.g. heat transfer from a cold object to a hot object)? Underscore doesn't work in Coffeescript's console I was wondering if there is any way to escape a CDATA end token (]]&gt;) within a CDATA section in an xml document. Or, more generally, if there is some escape sequence for using within a CDATA (but if it exists, I guess it'd probably only make sense to escape begin or end tokens, anyway).   Basically, can you have a begin or end token embedded in a CDATA and tell the parser not to interpret it but to treat it as just another character sequence.  Probably, you should just refactor your xml structure or your code if you find yourself trying to do that, but even though I've been working with xml on a daily basis for the last 3 years or so and I have never had this problem, I was wondering if it was possible. Just out of curiosity.  Edit:  Other than using html encoding... Wrong numeration in toc longer then one page Being a fairly new user something I don't seem to be able to locate is information on whether small edits to the title are considered as trivial edits. I see the usual recommendation when suggesting an edit is:     Avoid trivial, tiny one-letter edits unless absolutely necessary.   I can see the logic in that for most cases, but for example I just read a question with a title containing "Andriod" which would be trivial in one way but also affect the ability of users to locate the question using both the site and external search engines. Would it be frowned upon to suggest an edit for those cases? Is 3+1 spacetime as privileged as is claimed? I've often heard the argument that having 3 spatial dimensions is very special. Such arguments are invariably based on certain assumptions that do not appear to be justifiable at all, at least to me. There is a  on Wikipedia.  For example, a common argument for why >3 dimensions is too many is that the gravitational law cannot result in stable orbital motion. A common argument for &lt;3 dimensions being too few is that one cannot have a gastrointestinal tract, or more generally, a hole that doesn't split an organism into two.  Am I being overly skeptical in thinking that while the force of gravity may not be able to hold objects in stable orbits, there most certainly exist sets of physical laws in higher dimensions which result in formation of stable structures at all scales? It may be utterly different to our universe, but who said a 4D universe must be the same as ours with one extra dimension?  Similarly, isn't it very easy to conceive of a 2D universe in which organisms can feed despite not having any holes, or not falling apart despite having them? For example, being held together by attractive forces, or allowing certain fundamental objects of a universe to interpenetrate, and thus enter a region of the body in which they become utilized. Or, conceive of a universe so incomprehensibly different to ours that feeding is unnecessary, and self-aware structures form through completely different processes.  While I realise that this is sort of a metaphysical question, is 3+1 dimensions really widely acknowledged to be particularly privileged by respected physicists? Why am I getting a NoClassDefFoundError in Java? Trying to open a http website on any web browser (event telnet) gives a ‘ERR_CONNECTION_REFUSED’ or ‘connection timed out’.  However, the same sites can be opened using https. I tried doing a traceroute and it works fine.  I am new to OS X but have experience with Linux. How do I go about troubleshooting this issue?  Update  I think I've tracked down the culprit to a rule in pf (firewall).  The result of sudo pfctl -s nat is:  No ALTQ support in kernel ALTQ related functions disabled rdr pass inet proto tcp from 192.168.0.101 to any port = 80 -&gt; 127.0.0.1 port 9882   192.168.0.101 is the current ip address of the computer.  I tried to remove the rule with sudo pfctl -F all, but it is back after a few seconds. I didn't find the rule in the default configurations (/etc/pf.conf). And disabling pf with sudo pfctl -d has no effect on it.  Is this a malware issue? While im going through the derivation of E step in EM algorithm for pLSA, i came across the following derivation . Could anyone explain me how the following step is derived.   $\sum_z q(z) log \frac{P(X|z,\theta)P(z|\theta)}{q(z)}  = \sum_z q(z) log \frac{P(z|X,\theta)P(X,\theta)}{q(z)} $ What does linear time series refer to? Using property() on classmethods I have a class with two class methods (using the classmethod() function) for getting and setting what is essentially a static variable.  I tried to use the property() function with these, but it results in an error.  I was able to reproduce the error with the following in the interpreter: class Foo(object):     _var = 5     @classmethod     def getvar(cls):         return cls._var     @classmethod     def setvar(cls, value):         cls._var = value     var = property(getvar, setvar)  I can demonstrate the class methods, but they don't work as properties: &gt;&gt;&gt; f = Foo() &gt;&gt;&gt; f.getvar() 5 &gt;&gt;&gt; f.setvar(4) &gt;&gt;&gt; f.getvar() 4 &gt;&gt;&gt; f.var Traceback (most recent call last):   File &quot;&lt;stdin&gt;&quot;, line 1, in ? TypeError: 'classmethod' object is not callable &gt;&gt;&gt; f.var=5 Traceback (most recent call last):   File &quot;&lt;stdin&gt;&quot;, line 1, in ? TypeError: 'classmethod' object is not callable  Is it possible to use the property() function with @classmethod decorated functions? Alka Seltzer Model: formulas/models requested This evening I became fascinated with how my Alka Seltzer tablet disintegrates over time within a small portion of Diet Lipton Citrus Ice Tea. I used a nearly frozen cup; tall, as one might request in a middle-class restaurant.  It is interesting to notice that the Alka Seltzer tablet attempts to float to the top of the glass; but it just cant quite make it, e.g., it keeps bobbing up and down and finally it becomes complete residue.  What are the formulas for this, completely? What might the mathematical model look like from start to finish? My first identifications include, but certainly not limited to: measuring the cup, the milligrams deposited into the cup and of course a the makings of a typical tablet of Alka Seltzer excluding room temperature? Does "until [date]" mean "before that date"? What does until mean in the following?     You need to deliver this product within 2 days (until August 18, 2011)   to meet your deadline and get paid.   Does this mean that I have to deliver the product by 23:59 on 17 August 2011 or 23:59 on 18 August 2011? The order time is 21:04 on August 16 2011. $$e^{i} = e^{i2\pi/2\pi} = (e^{2\pi i})^{1/(2\pi)} = 1^{1/(2\pi )} = 1$$  Obviously, one of my algebraic manipulations is not valid. Why won't attribute modifiers add up on my armor?