Countable intersections in topological space

Question: If a T1 topological space is closed under countable intersections, does this necessarily make the topology discrete? It is easy to construct a counterexample if the topological space is not assumed to be T1, and it is also easy to see that the claim is true in a metrizable topological space. If the claim is false under the assumption that the space is T1, then what is the weakest condition required to ensure the topology is discrete?
Comment: Consider a cocountable topology for a counterexample. A condition under which it is true is first countability, and I don't think you can do much better than that.
Comment: Keyword: P-spaces.
Comment: A $T_1$ space is discrete if and only if arbitrary intersections of open sets are open.
Comment: Also a compact Hausdorff space in which the topology is closed under countable intersection, is finite (this is mentioned in Rudin, Duke 1956). Indeed, the assumption implies that all countable subsets are closed, while every infinite Hausdorff compact space has an infinite countable discrete subset, necessarily non-closed.
Comment: A Hausdorff non-discrete topological space in the topology is stable under countable intersections is as follows: consider a set $X\sqcup\{\infty\}$ with $X$ uncountable, and say that a subset $U$ is open if either $\infty\notin U$, or if $U$ has countable complement. Clearly this satisfies the required conditions. (Actually, all its countable subsets are closed and discrete.)
Comment: Every connected regular space where the countable intersection of open sets is still open is still open is a single point.
Answer: Here I am gathering information in the comments along with some information of my own to form an answer.
A $P$-space is a regular space where every countable intersection of open sets is open. There are many examples of $P$-spaces which are not discrete. For example, the co-countable topology is a topological space $(X,\mathcal{T})$ where $X$ is an uncountable set and $\mathcal{T}$ consists of all subsets $R\subseteq X$ where $|R^{c}|\leq\aleph_{0}$ or $R=\emptyset$. The co-countable topology is a $T_{1}$-space where the intersection of countably many open sets is still open.
An Alexandroff space is a space where the intersection of arbitrarily many open sets is open. The only $T_{1}$-Alexandroff spaces are the discrete spaces.
Here are a few examples of benign topological properties for which the only $P$-spaces which satisfy those properties are the discrete spaces. From this point on, let us limit our scope to only the regular spaces.
Connectedness: Every $P$-space is zero-dimensional (a zero-dimensional space is a space with a basis of clopen sets). Therefore, any connected or locally connected regular $P$-space consists of a single point. Furthermore, any regular space $X$ with a connected subset consisting of more than one element cannot be a $P$-space.
Disconnectedness: A topological space $X$ is said to be extremally disconnected if for each open set $U$, the closure $\overline{U}$ is still open. A cardinal $\lambda$ is said to be below the first uncountable measurable cardinal if there does not exist a non-principal ultrafilter $M$ on $\lambda$ such that the intersection of countably many elements of $M$ still belongs to $M$. Every uncountably measurable cardinal is very large and it is consistent with ZFC that there are no measurable cardinals. Every extremally disconnected $P$-space of non-measurable cardinality must be discrete, but there are extremally disconneced $P$-spaces of measurable cardinality such as the one in this answer (this space happens to be the poset used for Prikry forcing).
Compactness: Every compact $P$-space is discrete and finite. In fact, in every $P$-space, every countable subspace must be closed. However, every infinite compact space must have infinite discrete non-closed subspace, so infinite compact spaces cannot be $P$-spaces at the same time. If $X$ is a $P$-space which is pseudocompact, countable compact, or locally compact, then $X$ must be discrete.
Countability: Suppose that $L$ is one of the following properties: metrizable spaces, second countable, first countable, points are $G_{\delta}$, sequential spaces. Then the only $P$-spaces that satisfy property $L$ are the discrete spaces.
Non-examples: There are many topological properties for which there are many non-discrete $P$-spaces which satisfy those properties including the following (somewhat redundant) list: completely regular, normal, paracompact, Lindelof, realcompact, scattered, the Baire property and its generalizations, the negation of the Baire property.


Correct use of Prepositions

Question: Which of the following is grammatically correct
a)  The documents are attached along with.
b)  The documents are attached in.
c) The documents are attached.
d) The documents are attached with.
Please first rate which of above is correct then suggest any better structure if you have.
Comment: Please include more detail to explain why this structure is confusing to you, and what research you have done to answer it.  Otherwise the question should be closed as proofreading.
Answer: The only one that makes sense as is, is:

The documents are attached

Assuming it's something like an email and the sender is notifying the receiver that something is attached with the mail.
The other three are basically unfinished sentences, so you would need to include what they are in, or what they are with
For example:

The documents are attached in this email
Comment: Please review the site rules.  We try not to answer "proofreading" questions here, unless the question includes enough detail that the answer may be useful to someone else.  Instead this question should be closed.
Comment: Note that *attached **with** this email* and *attached **to** this email* could also be considered correct. The problem with the question is not that three of the example sentences are using incorrect prepositions, but that they are incomplete sentences. If a), b), and d) all ended with *this email*, they would all be correct.
Comment: @JasonBassford - yep I agree, I did say they were unfinished sentences as they stand.
Comment: I do agree I couldn't perceive the sense, as well. But the problem of mine being, I encountered the question as mcq, as it is,  in annual paper of mine. So I thought if someone could tell me the best among choices. Well thanks for response!

Correct use of Prepositions


Can my S Corp pay my personal tax liability and can my S Corp be able to deduct the taxes?

Question: I understand S Corps are flow through entities so if I am paying the net income on my personal taxes then can the S Corp pay for the taxes due?  Also can the S Corp be able to deduct the taxes paid as a deduction?
Answer:
can the S Corp pay for the taxes due?

Why? Why would the corporation, a separate legal entity, pay your personal obligations? Do you want to pierce the corporate veil? Because that's how you pierce the corporate veil.

Also can the S Corp be able to deduct the taxes paid as a deduction?

Of course not, how is it a deduction for the corporation? It's not a legitimate business expense.
The corporation can pay you a salary, and withhold taxes on your behalf from that salary. In fact, the corporation is required to do that if it's profitable (you're required to pay yourself a reasonable salary before taking distributions). But the corporation cannot and should not pay your personal obligations.
Comment: @Dallat it is not a tax incurred *by the corporation*. It is a tax incurred *by you* because you received net profit from the corporation, as the owner.
Comment: The corporation does pay me a salary and with withholdings I am entitled to a refund.  However when the corporations net income flows over to my personal then I now owe taxes.  The taxes due is from the corporation.  If the corp is able to pay and be able to deduct the annual $800 corp tax then I don't see how this is any different because it is a tax incurred by the corporation.


According to the Catholic Church, is practicing spiritism moral?

Question: What does the Catholic Church teach about Spiritism, especially the Kardecist Spiritualism Doctrine (covered in the link above)?  According to the Catholic Church, it is wrong to try to communicate with the dead and to gain knowledge from spirits?
Comment: Welcome to Christianity.SE! Your question *could* be a good one here, but as it is now, it's a little too broad to be answered objectively. Are you looking for the views of any particular branch of Christianity, such as Catholicism or Protestantism? We're not about what individual Christians believe, but about what whole groups of Christians believe.  See: [How we are different than other sites](http://meta.christianity.stackexchange.com/questions/1808/how-we-are-different-than-other-sites).
Comment: I am a catholic so I am most intrested in this branch of Cristianity but I am open for views from other branches too :)
Comment: I've revised your question to ask for the Catholic view, so that it is inline with site guidelines.  If you later want other perspectives, you are welcome to ask more questions.
Answer: The Catechism of the Catholic Church has a paragraph specifically referenced as "Spiritism — forbidden" in its index, and which unequivocally and categorically condemns the practice of spiritism.

2117 All practices of magic or sorcery, by which one attempts to tame occult powers, so as to place them at one's service and have a supernatural power over others — even if this were for the sake of restoring their health — are gravely contrary to the virtue of religion. These practices are even more to be condemned when accompanied by the intention of harming someone, or when they have recourse to the intervention of demons. Wearing charms is also reprehensible. Spiritism often implies divination or magical practices; the Church for her part warns the faithful against it. Recourse to so-called traditional cures does not justify either the invocation of evil powers or the exploitation of another's credulity.
Comment: Well, yes, except that Kardec [mentioned in the question] used seances. These occasions either tame occult (hidden) powers, or they exploit credulity.
Comment: This condemnation seems to apply primarily to the practice of magic and sorcery. Though spiritism is mentioned, by saying that spiritism "often implies divination or magical practices" it suggests that the actual condemnation is of divination or magical practices in connection with spiritism. I.e. the condemnation doesn't seem quite as unequivocal and categorical as suggested in the commentary on the passage.
Comment: Note that I'm not trying to defend spiritism. Just to clarify the Catholic Church's exact position on it.


Bigdata use cases

Question: we are trying to create a dashboard using BigData. The Data are currently transacted in SQLServer and the front end is in MVC. As the data flow is extremely high to analyse using SQLServer itself it is decided to use BigData. I had chosen Cloudera Manager CDH, SQOOP to import data from SQLServer to HIVE and running the analytic using IMPALA. Decided to up the results with Microstrategy to provide the charts in mobile platform to the clients.
    Any Ideas or suggestion are welcome to improve the process?
Answer: Looks like you're off to a great start. Remember your analytics can be done with a multitude of tools, not just Impala.
Once you're in Hadoop, Hive and Pig give a lot of power (more available with UDFS) with an easy learning curve.
If you eventually want to do some iterative use cases (and exploit machine learning), you might want to check out Spark (those two things are in its wheelhouse), which is not constrained by (to?) MapReduce.
Tons of great tools available. Enjoy the journey.
Answer: I would consider to use two stages. Data Analysis and Data Visualisation.
Use two stages makes the solution more flexible and decouple the responsiblility.
Data Analysis

Ingest the data (Include cleaning), Sqoop can do the ingest step, might require extra steps to cleaning the data.
Explore/Analyse the data, Apache Spark is a very flexible and powerful tool.
Store the analyse result in a specified format

Data Visualisation

Load the data from data analysis phase
Visualise it. Using Highcharts/Kibana/Dashing. Or use D3 create customised dashboard.

Bigdata use cases


Adding vertices

Question: Is there a way to add vertices to an object in edit mode? Say I want to add some more vertices to a row of vertices of a torus, but do not want to subdivide the whole thing
Comment: select what you want to subdivide and subdivide it?
Answer: If you press Ctrl+R. you will get the same result as adding a Loop Cut - except it adds a vertice(s) to the string instead of edges.  Then just scroll to decide how many.
This will only allow you to add vertices between two previously added vertices, however.  So, you may want to consider @lemon's suggestion, of selecting the area of vertices where you want to add more and subdividing that area.
Hope that helps!
Answer: If you have lets say an edge which has only 2 vertices but you want 3 on 1 edge which means simply that you want to make it into 2 edges , (What i decipher from your question) , then you can select your 2 vertices and right click>Subdivide the vertices
Answer: @SHkha's answer is what I would recommend, you positively know where your new vertex is.
However, if, for example, you have a long edge, whose center is inconveniently out of view, you have the option of selecting a vertex you want to duplicate, hovering over the edge you would like the copy to be in, and hitting AltD.
You can either follow this directly with a transform, (e.g AltDX.5), or right-click to drop the copy in place, still selected, right on top of  the original.
You can then follow up with your transform, or, say, GG to slide it down the edge.

Adding vertices


UiTableview ContentInset

Question: I am working on very small app. In this app I am using UIrootviewController's table view to display some content in it. I want that content to be displayed at particular position so I am setting its contentInset. when I do it in viewDidLoad or in xib it is not showing any effect at first time. I have written it in shouldAutorotateToInterfaceOrientation function it is giving me proper location after orientation change but at first time it is showing table content at same location whatever may be the content insets values
here is my code for setting content insets
self.tableView.contentInset = UIEdgeInsetsMake(120, 150, 0.0, 0.0);

I have wrote this code inside viewDidLoad, and shouldAutorotateToInterfaceOrientation
 but it is not showing any effect when application starts. is there any other method to achieve this.
i even tried setFrame, but did not worked.
Answer: I think you may be confused about what method to use. If you want to set the position and size of the view you should set its frame.
Answer: Put your code in the viewWillAppear method.
Answer: Try the following in viewDidLoad or viewWillAppear:
self.tableView.contentInset = UIEdgeInsetsMake(120.0f, 150.0f, -120.0f, -150.0f);

UiTableview ContentInset


What causes the chemical taste in commercial bakery products?

Question: Over the last 10 years or so, I've noticed a chemical taste in most commercial bakery goods (not packaged factory ones but rather the in-store bakery at a grocery store). It's seems to be mostly on the base of the item or around the outside. For example, the base and crust of a danish/croissant will have the taste, but not the inside dough. Does anyone know what causes this taste? Is it perhaps a glaze or a non-stick spray..?
Comment: Do others taste this as well, or are you the only one you know that notices it? Some people are more sensitive to certain flavors and scents than others.
Comment: I'm more sensitive to taste than most. Others can also taste it, but they don't seem as bothered by it as I am.
Answer: This could be a number of factors.

Parchment sheets are ubiquitous in professional, non-commerical bakeries. As the sheets are treated to impart some nonstick properties, you may be tasting some residue from that paper, especially if the bakery is using bleached sheets. You can easily test this by baking something at home on parchment and seeing if it has that same flavor. This is unlikely but hey, worth a shot.
Commercial pan release sprays will sometimes contain suspended flour, anticaking agents (silicon dioxide for example,) and certain anti-foaming agents. When I worked in a bakery we would occasionally use a commercial spray like that when making items that were prone to sticking even on parchment, or when baking things that would be in direct contact with our metal baking pans (brownies, muffins, etc.) Most of the time we opted for a spray that was mainly canola oil and propellant, but occasionally we would use other sprays with additional ingredients.
Eggwash (or commercial substitute) is a potential culprit, especially as you mentioned croissants and danishes. We used a mix of egg and water sprayed on to certain items (mainly with puff pastry) before baking, but larger bakeries may use a product like Bake-Sheen sprayed before or after baking for the same effect. Those sprays contain several chemicals and would definitely impart a certain flavor to the items. Moreover, there is a possibility it could drip down and pool around the bottom of the item, creating that
In terms of glazes, those would likely depend on what is being used by the bakery in question, and they won't always be similar. If you're experiencing this regularly from one place or another, it might help to ask what they glaze their danish or other items with. We used an apricot glaze product to give our sweet puff pastry items a shine and added sweetness. These commercial glazes likely have artificial or chemical flavoring agents in them, which may impart an off flavor.


Is the work done by friction considered as heat?

Question: In the first law of thermodynamics, We write the change in internal energy in terms of heat exchanged and work done. The answer to the above question doesn't matter if our final aim is to find the change in internal energy. However, When calculating the efficiency of an irreversible cycle, We always write difference of the heat taken in and heat rejected to be the work done by the system. In this, are we also including the work that is being done against friction?
Comment: Work done by friction leads to a loss of energy
Comment: It depends on whether the frictional work occurs within the "system" containing the working fluid, or whether it occurs outside of the system, and is part of the work done on the surroundings.
Answer: Work done by friction is still work rather than heat. It is worth noting however that it is an irreversible process, not a reversible form of work.
In terms of efficiency, however, we are normally interested in "useful" work done by the system, or work done by the system on some other external system and so would not count work done against friction.
Comment: When we derive clausius inequality we consider the work done in that irreversible cycle as Q(high)-Q(low) for the work done by system, Why don't we also substract the work done by friction? If we only want to take into account  the "useful work".
Comment: I am not totally sure what you are getting at. Could you explain the proof of Clausius' theorem that you are looking at in more detail?


British TV series with robot dog and post-apocalypse

Question: I watched as a child, so not long ago, but because of my age, I must have watched the German dub, or there were subtitles, which may explain my confusion. Some memories are jumbled, so it is hard to recall, but there were aliens in the show, and a girl was crushed by some metal. The dog saved the main characters a lot, who were children. It was a children's show.
Comment: Was it a cartoon or live-action, for example?
Comment: This question would be improved by going through the checklists here; [How to ask a good story-ID question?](https://scifi.meta.stackexchange.com/questions/9335/how-to-ask-a-good-story-id-question)
Answer: There was a K-9 children's series; it would have been broadcast around 2009-2010.
The title character is a robot dog, based on one seen in Doctor Who and The Sarah Jane Adventures. The owner of the the copyright on K-9 allowed the character to be used (sparingly) in those shows, but was not allowed to reference either show in this series.
As I've never seen it, I cannot say if it would have even seemed as if it was post-apocalyptic. It appears to have been set in London in the "near future"; however, there was an element of time travel to the show, which might have resulted in adventures with a post-apocalyptic backdrop.
It was a live action show, with CGI.
I should note that the Wikipedia page lists a number of countries where it was shown, and the channel it was on in each, but that Germany was not included in that list. Not sure if that's just missing information, or if that means it wasn't shown in Germany.
Here's a link to the first episode on YouTube (in English):
Comment: It could also be the Sarah Jane Adventures, another Doctor Who spin-off in which K-9 appears. I think there were a couple of episodes of it that showed potentially apocalyptic events.
Comment: @ConMan - Not impossible, but I wouldn't say he "saved the main characters a lot, who were children", in SJA.
Comment: True, I think your answer is much more likely. Just mentioning it in case.
Comment: No problems - always good to provide alternatives!
Comment: Thank you, this is it! I did not know it was a doctor who show.


Change sort order with shortcuts in Midnight Commander?

Question: How to change sort order with shortcuts? I know that I can put that in ~/.config/mc/mc.keymap file but what exactly to type?
Answer: Yes, of course you can put your preferred shortcuts in ~/.config/mc/mc.keymap to override the default in /etc. don't forget to put the section. e.g [main] , [panel].
if you want to change the default keymap, but you don't know what to type, you can always refer the format in /etc/mc/mc.default.keymap
this is mine
[panel]
Sort = alt-!
SortPrev =
SortNext =
SortReverse = alt-@
SortByName = alt-#
SortByExt = alt+$
SortBySize = alt-%
SortByMTime =  alt-^

according to Use a hotkey to toggle between two preferred sort orders and sort hotkey
Comment: For some reason this doesn't work with `alt-·`, [a middle dot (U+00B7)](https://unicode-table.com/en/00B7/) which is over 3 on es/Spanish layout (`localectl | grep 'X11 Layout'`).


What causes low power on hypothesis tests?

Question: I've been doing hypothesis tests to compare two proportions in a product. Although the sample size is supposed to be more than enough based on the population and $\alpha$ (type I error), the power of the experiment ($\beta$, type II error) is very low. Why is that?
Comment: Usual culprits: sample size, difference in means, standard deviations of means, $\alpha$.
Answer: There isnt a lot in your question to go on. So, you might not get much of an answer to your specific question.
A few thoughts.
1. Power = 1-beta, so if your beta is very low, then your power is actually very high.
2. The sample size calculation you performed should indicate a sample that is big enough to reject the null with a Type 1 error equal or less than alpha and Type 2 equal or less than Beta. But your sample size calculation is just an estimate based on an educated guess. Depending on what tests you are running and how the sample size was calculated you likely used an effect size from the literature or from a pilot study. If you are getting very different results than expected, it could either be that there was a flaw in the original sample size calculation, or there is always the chance that you have drawn an unrepresentative sample.


What does 転勤になる mean?

Question: Is it an abbreviation of 転勤することになる? How is it different from just 転勤する?
Example: 父は京都支店へ転勤になりました
Is it similar to the humbleness of 結婚になりました!?
Answer: I assume you already know the basics of how ことになる works.
転勤することになりました normally refers to a future event (relative to the time of the statement). "It was decided that (someone) would be transferred."
転勤になりました can also refer to a future event, in which case the two sentences are interchangeable. But 転勤になりました can be used also to refer to a past event, like "(Someone) was transferred (following someone's decision)". So 先月転勤になりました usually means this person was actually transferred last month, whereas 先月転勤することになりました usually means such a decision was made last month (but the actual transfer may happen much later).
Note that noun + になる works like this only when the noun is inherently related to some decision/judgement (有罪, 合格, 採用, 離婚, etc.). Otherwise, noun + になる may mean something different. For example, 勉強することになりました means "(It was decided that) I am going to study", whereas 勉強になりました normally means "I learnd a lot / It was a good lesson".
Answer: In this case, することになる adds a "ended up/resulted in" to  the sentence
It emphasizes on the result of getting a job transfer and makes it a decisive fact
The meaning for 転勤になる and 転勤する is almost the same imo, only difference is that 転勤する is the verb form

What does 転勤になる mean?


Wanton stranger's

Question: Would you please tell what does the following mean?
Thanks in advance.
"... her skin flushed, and her body felt like a wanton stranger's.
Comment: What does a dictionary say???
Comment: Perhaps also add some context, where did you see this sentence?
Answer: This sounds like a sentence from a Harlequin romance novel, US publisher of soft-core chick lit.
Wanton is defined as...

done, shown, used, etc., maliciously or unjustifiably: a wanton attack; wanton cruelty.
deliberate and without motive or provocation; uncalled-for; headstrong; willful: Why jeopardize your career in such a wanton way?
without regard for what is right, just, humane, etc.; careless; reckless: a wanton attacker of religious convictions.
sexually lawless or unrestrained; loose; lascivious; lewd: wanton behavior.
extravagantly or excessively luxurious, as a person, manner of living, or style.
luxuriant, as vegetation.

While nearly all of these definitions will work, without more context it's hard to pin down the author's precise intention. The leading contenders are the latter three (definitions 4-6) with their sexual connotations. So wanton, in this case, likely refers to a 'forbidden' pleasure.
Stranger's, on the other hand, is most likely a reference to a feeling of alienation akin to psychological dissociation of someone's mind from their body rendering them unable to make conscious, willful decisions of their own volition.
Putting all of this together a plausible interpretation of the meaning of the phrase is...

...her skin flushed, and her body felt a release of sexual luxuriance so unfamiliar it was as if it belonged to someone else...
Comment: Please resist doing the research the OP should have done!
Comment: @HotLicks  Will observe that admonition going forward.

Wanton stranger's


Benefits of peering with Transit Providers at exchange points

Question: Whilst investigating choices of IXPs and browsing through member lists, I realised that Hurricane Electric publicly peered on AMS-IX and other popular IXs. I also came across their peering policy that says they are open to peering with anyone. Whilst I can see the benefit of HE peering with networks on an exchange, I can't quite understand how the other party is mutually benefited. Does peering with a large transit provider at an exchange point offer any benefits for myself? Does it provide the equivelant to (or close to) a transit connection with HE? On a peering agreement you normally don't announce routes announced to you on the IX back up to your own peers, so that would infer it's not the equivelant of transit, so does it provide any increased connectivity?
Comment: There is an open document here about the benefits of peering: https://docs.google.com/document/d/1i2bPZDt75hAwcR4iKMqaNSGIeM-nJSWLZ6SLTTnuXNs/edit?usp=sharing
Answer: The peering is for connectivity between HE networks (basically their transit customers) and your networks (your customers) and not for transit between you and the Internet as a whole.
The benefit is they will accept and deliver traffic to/from their transit customers without a complex peering agreement or any fees.
Comment: So basically, anyone who purchases transit from HE would be reachable over a peering connection with HE?
Comment: Yep, pretty much.  HE would only be announcing their networks to you over bgp, and you should do the same.
Comment: @yoonix so HE would also announce their transit customers prefixes across this IX peering session? I was under the impression you only announced your own routes with peering?
Comment: Announcing a transit customer's route is basically what transit is.  You can't really offer transit if HE doesn't announce to the world that the customers' networks are reachable are reachable through their network, packets flow in both directions.
Answer: The general idea of peering is that the two operators agree to directly exchange traffic destined to each other's own networks/customers.
Peering generally makes sense when doing this will save money and improve connectivity for both parties (typically that would imply that they operate on similar scale).
It sounds like the described scenario may be one where you're not really peers (stricly speaking) but that HE is just very open about who they agree to do peering with.
If you're a significantly smaller player and a bigger player is still willing to exchange any traffic at all for free I would think it's more likely to be good for you than for them, provided that the traffic exchanged this way is a non-negligible portion of your total traffic.
Often the bigger player may rather see such a situation as an opportunity to have you instead be their customer and refuse to peer on that basis. (You get free access to much more than they do if you peer.)
If you instead were to buy transit from HE I would assume they could give you connectivity to the full Internet if you need that, but you would obviously be paying them for that traffic.
Peering with an internet exchange is probably a worthwhile read as well.
Comment: I've actually read that article. For me it's a bit different as I know what I'm doing and I have a very good reason to be peering with an exchange (large volumes of traffic between us and Amazon, Google and Microsoft). I was just wondering if it was worth it to peer with HE considering we were already present at the IX.


Will google remove the old caches if noarchive is added to robots.txt?

Question: If you want google's cache of your site to remain unchanged, is it a good idea to add noarchive to robots.txt? Or will this wipe out your caches?
Comment: As a note if you're interested, Cloudflare free plan includes a more "on demand" sorta cached site. Only comes online if your server is down, whereas G always makes cached available. I'm not affiliated with CF just figured I'd let ya know.
Answer: Firstly, there is no such thing as noarchive in robots.txt. You need to add a meta tag to all pages on which you wish to prevent caching:
<meta name="Googlebot" content="noarchive">

When you have done that, then Google will stop caching the page entirely and won't show a cache link at all. There is no way to keep showing the old cache while preventing new caches.
Answer: The only problem is, it could take a month before Google re-crawls your entire site.
add_action( 'wp_head', 'add_meta_tag' );
function add_meta_tag() {
echo '<META NAME="GOOGLEBOT" CONTENT="NOARCHIVE">';
}

Add this PHP to your child themes functions file
Then re-build your site map
And submit the sitemap URL to Webmaster Tools > Crawl > Fetch as Google
Comment: Whoe man, please note that the above script is for WordPress. We don't need folks dropping in undefined functions to their non-wp platforms. Also you are better off doing that in htaccess using X_ROBOTS header for a fully encompassed flag. Think media files and stuff.


How can I know my rating in chess

Question: I play chess sometimes.
I don't know any chess strategy. I just know the direction of each piece.
How can I know my rating?
Comment: Then you don't have a rating.
Answer: If you do not play in tournaments, then you do not have a rating. You are unrated.
If you play online, then you will have a rating. However, this is unofficial and cannot be used anywhere else.
Answer: There isn't one rating. Each site or chess federation would rate you differently. Even if two different organizations use the exact same rating system, the separate pools of players make the numbers incomparable. You can find your rating for a certain organization by playing enough games for the statistics to become meaningful.
What's this about statistics? Ratings are approximations of our playing strength.  Rating systems are based upon opponents' ratings and use statistics to predict the outcome of games. The results of games are used to adjust ratings. The more we play, the more accurate the ratings become.
I don't know where you're located, but in the USA, you'd likely be rated about 800. An average club player is about 1500. The 700 point difference would mean you'd have virtually no chance of defeating someone who had a poor chance of defeating that average player.
Comment: 800 seems like it's pulled out of a hat.  It could just as easily be 200, from the given description.  800 is very weak compared to a club player, but someone at that level does know more than just how to move the pieces.
Answer: So long as you understand the tules of the game, playing on a chess based website such as Chess.com will give you an approximation of your rating. That would be a good starting point, although in general a beginner would start at around 1200 elo. (In chess, we measure one's rating in elo)
Comment: beginners start at 100 in USCF.  The real question is how beginner is a beginner.
Comment: "*In chess, we measure one's rating in elo.*" Not everywhere. Also, it's Elo, with a capital "E", as it is named for its [inventor](https://en.wikipedia.org/wiki/Arpad_Elo).
Answer: your rating is 100 but only because they dont go lower
start reading some books to improve
play over grandmaster games to get a feel for what good moves look like in an opening
work through tactical problem collections to learn to recognise patterns of winning moves
to get a provisional rating play in rated events
to get an established rating play in lots of events
Comment: again some coward downvoted a correct answer without saying why.
Comment: @edwinaoliver: The downvote wasn't mine, but last time I tried to leave an explanation for a downvote I got a pop up saying such practice is discouraged - a 180 from how SE once operated. Also, this isn't a "correct answer"; an unrated player is simply unrated, not 100. Furthermore, without knowing the player's federation you don't know what the minimum rating would be - while I believe the Brits are changing their system, in the past a 100 rating in England was considered decent for a club player.

How can I know my rating in chess


How a psychiatrist must talk?

Question: I wrote a scene of a psychiatrist talking to a traumatized child, and I read and read it several times but still not convinced and satisfied with it. Are there any book recommendations or extracts that deal with the same "theme", if so I may say, that could help guide me or at least, give me a general idea on the way psychiatrists talk?
Answer: How old the child is will determine the approach the psychologist/psychiatrist will have.
Also, another matter to note is that depending on the trauma no one will be able to simply talk to the kid and gather useful information no matter his education and reputation.
However, if the talk was conducted in the form of therapy and for instance, the kid was about 8 years old, sessions would most likely consist of multiple interactions with toys, drawings, and games to slowly but surely include the subjects of the possible reason for the trauma.
About how he should talk, usually playfully (as to keep the pressure down) and treading very carefully about the subject to avoid losing trust with the child.
Comment: Also, when talking to a child a therapist can never ask leading questions. It can derail any criminal investigation into the events and it can even implant the idea of abuse where there was none. Some googling also suggest treatments like TF-CBT, further googling might give details on how such therapies work.
Comment: I should also add, that's a good therapist... this could of course be a crap therapist that leaves the kid scarred for life... https://thepsychologist.bps.org.uk/volume-30/july-2017/false-memories-childhood-abuse
Answer: A psychiatrist should talk how the author wants them to. That's the most detail any stranger can give you. I'll just try to illustrate what factors they should consider.
If the aim is realism, do your research; if the aim is something else, you'll need to consider the needs of plot and characterization, and the latter's influence depends on, among other things, whether the psychiatrist, patient, both or neither is a main character.
Realism may or may not be your concern, but authors find it convenient to depart from it in certain typical ways. It's common for fictional psychiatrists to talk, in particular, at far greater length to the patient than is typical in real-life sessions today. The stereotypical hour-long discussion of one's childhood and dreams on a couch contrasts with the modern practice of determining in minutes what the symptoms are, and what combination of drugs, CBT etc. would be most effective.
I don't seek to disparage authors for the "old-fashioned" approach. Maybe it's more interesting, or fits their story well; maybe it's what they know, or think their audience do; maybe the story is set in a time and place where it would be more relevant than I make it sound, and that's another consideration.
Frasier is worth discussing in this regard because it features multiple psychiatrists, most prominently the titular Frasier Crane and his brother Niles, and to a lesser extent the former's ex-wife Lilith and late mother Hester. Needless to say, insofar as their on-the-job language is showcased, it differs in ways that make sense in-universe (not to mention being funny). They worked in different times and places, and their careers were very different.
Most of their known speech is off-the-job; they differ there too, in part because their personalities differ. The off-the-job differences naturally filter into the on-the-job aspects. Of course, this example is less relevant to an author who wants a psychiatrist to only appear in an on-the-job setting, either prominently or just in one scene. So clearly, there's no standard answer one can give on how to voice a psychiatrist.
I apologize if I've made it sound like there's a sharp contrast between two choices here, to write accurately and to write something interesting. There... is and there isn't. To return to the example of Frasier, there are different kinds of psychiatrist. Lilith is a researcher (and as best I can tell so was Hester), while Niles has a practice and Frasier offers radio "McSessions", to borrow Niles's disparaging description of them. But the brothers also have different theoretical backgrounds: Frasier is Freudian while Niles is Jungian. The latter fact leads to such hilarious lines as, "so no blaming mother today" when Niles fills in for Frasier. On the one hand, the scriptwriters no doubt proved some of their research in the inclusion of this difference between the brothers.
On the other hand, neither Freud's ideas nor Jung's are anywhere near as well-entertained among psychiatrists or psychologists as there once were. (Again, your chosen setting may make all the difference.) Theory, like practice (both have changed over time due to evidence), informs the way a psychiatrist would talk.

How a psychiatrist must talk?


Create a DApp using Geth

Question: I need to create a sample DApp from scratch within a private blockchain using Geth. Can anyone post links of sample apps which have been made in such a way for reference.
Answer: We can develop full stack dApps(Decentralized Applications) based on Ethereum Blockchain using Truffle, Solidity and Web3 tech stack by creating your own Ethereum private network and a private single geth node(geth is the the command line interface for running a full ethereum node)
I have demonstrated how to build your First Full Stack 'Hello World' dApp on Ethereum Blockchain with Solidity, Truffle and Web3 tech stack. You'll be able to develop more dApps on real use cases using the template I have created for 'Hello World' dApp. Please find the link below:-
Build Your First Full Stack 'Hello World' dApp on Ethereum Blockchain
Hope, this helps. Please comment down your issues if any.
Answer: Most of the work required to build a Dapp for the Ethereum mainnet and a private Ethereum chain is identical. In fact, if you've been deploying your Smart Contracts to a private testnet (for testing before deploying) it's the same.
Really the only thing that might needs to change is the configurations pointing to how to instantiate the web3 provider, but if your Dapp is running a local, private Ethereum node then the code doesn't need to change at all; just the way that the Geth instance on the box is started.
Here are some links that you might find useful:

http://truffleframework.com/boxes/ - lots of sample Dapps
http://truffleframework.com/docs/advanced/configuration#networks - configurations for deploying to other networks with Truffle
https://dickolsson.com/building-dapps-on-ethereum-part-6-private-testnet/
Answer: Here are some sample references :-
1) https://medium.com/@mvmurthy/full-stack-hello-world-voting-ethereum-dapp-tutorial-part-1-40d2d0d807c2
2)  http://truffleframework.com/tutorials/pet-shop
Comment: Thanks for the help! But the issue is that we are using a Blockchain simulator, Ganache in both the cases. I was looking for references that are helpful from creating a blockchain from scratch.

Create a DApp using Geth


How to stop ipad from auto locking while play games?

Question: I know I can switch off auto-lock altogether, but actually I just want to prevent the screen from being locked when I am playing games.
Comment: Those games are able to be rendered in different orientation? I'm not sure I understand the question - You have auto-lock switched ON, but You want it to be OFF only when playing games?
Answer: If the game maker didn't program the screen to not lock, you have to use Apple's switch for the entire system. It's hard to imagine many games where you don't touch the screen once every 5 minutes, but if so, request the game developer to add a switch or setting at overrides the system default for their game.
Settings App > General > Auto Lock
Then you can choose between
<code>- 1 Minute
- 2 Minutes
- 3 Minutes
- 4 Minutes
- 5 Minutes
- Never
</code>


Integrating functions that return an array in Python

Question: I have a lot of data to integrate over and would like to find a way of doing it all with just matrices, and would be willing to compromise on accuracy for a performance boost. What I have in mind is something like this:
import numpy
import scipy

a = np.array([1,2,3])

def func(x):
    return x**2 + x

def func2(x):
    global a
    return a*x

def integrand(x):
    return func(x)*func2(x)

integrated = quad(integrand, 0, 1)

So I am trying to integrate each element in the array that comes out of integrand.
I'm aware that there is a possibility of using numpy.vectorize() like this:
integrated = numpy.vectorize(scipy.integrate.quad)(integrand, 0, 1)

but I can't get that working. Is there a way to do this in python?
Solution
Well now that I learnt a bit more python I can answer this question if anyone happens to stable upon it and has the same question. The way to do it is to write the functions as though they are going to take scalar values, and not vectors as inputs. So follow from my code above, what we would have is something like
import numpy as np
import scipy.integrate.quad

a = np.array([1, 2, 3]) # arbitrary array, can be any size

def func(x):
    return x**2 + x

def func2(x, a):
    return a*x

def integrand(x, a):
    return func(x)*func2(x, a)

def integrated(a):
    integrated, tmp = scipy.integrate.quad(integrand, 0, 1, args = (a))
    return integrated

def vectorizeInt():
    global a
    integrateArray = []
    for i in range(len(a)):
        integrate = integrated(a[i])
        integrateArray.append(integrate)
    return integrateArray

Not that the variable which you are integrating over must be the first input to the function. This is required for scipy.integrate.quad. If you are integrating over a method, it is the second argument after the typical self (i.e. x is integrated in def integrand(self, x, a):). Also the args = (a) is necessary to tell quad the value of a in the function integrand. If integrand has many arguments, say def integrand(x, a, b, c, d): you simply put the arguments in order in args. So that would be args = (a, b, c, d).
Answer: vectorize won't provide help with improving the performance of code that uses quad.  To use quad, you'll have to call it separately for each component of the value returned by integrate.
For a vectorized but less accurate approximation, you can use numpy.trapz or scipy.integrate.simps.
Your function definition (at least the one shown in the question) is implemented using numpy functions that all support broadcasting, so given a grid of x values on [0, 1], you can do this:
In [270]: x = np.linspace(0.0, 1.0, 9).reshape(-1,1)

In [271]: x
Out[271]:
array([[ 0.   ],
       [ 0.125],
       [ 0.25 ],
       [ 0.375],
       [ 0.5  ],
       [ 0.625],
       [ 0.75 ],
       [ 0.875],
       [ 1.   ]])

In [272]: integrand(x)
Out[272]:
array([[ 0.        ,  0.        ,  0.        ],
       [ 0.01757812,  0.03515625,  0.05273438],
       [ 0.078125  ,  0.15625   ,  0.234375  ],
       [ 0.19335938,  0.38671875,  0.58007812],
       [ 0.375     ,  0.75      ,  1.125     ],
       [ 0.63476562,  1.26953125,  1.90429688],
       [ 0.984375  ,  1.96875   ,  2.953125  ],
       [ 1.43554688,  2.87109375,  4.30664062],
       [ 2.        ,  4.        ,  6.        ]])

That is, by making x an array with shape (n, 1), the value returned by integrand(x) has shape (n, 3).  There is one column for each value in a.
You can pass that value to numpy.trapz() or scipy.integrate.simps(), using axis=0, to get the three approximations of the integrals.  You'll probably want a finer grid:
In [292]: x = np.linspace(0.0, 1.0, 101).reshape(-1,1)

In [293]: np.trapz(integrand(x), x, axis=0)
Out[293]: array([ 0.583375,  1.16675 ,  1.750125])

In [294]: simps(integrand(x), x, axis=0)
Out[294]: array([ 0.58333333,  1.16666667,  1.75      ])

Compare that to repeated calls to quad:
In [296]: np.array([quad(lambda t: integrand(t)[k], 0, 1)[0] for k in range(len(a))])
Out[296]: array([ 0.58333333,  1.16666667,  1.75      ])

Your function integrate (which I assume is just an example) is a cubic polynomial, for which Simpson's rule gives the exact result.  In general, don't expect simps to give such an accurate answer.
Comment: For completeness, I'd mention [scipy.integrate.romb](https://docs.scipy.org/doc/scipy/reference/generated/scipy.integrate.romb.html) which can squeeze a somewhat more accurate result out of the same data (provided it has `2**k+1` samples).
Comment: I know this answer is nearly five years old, but it really helped me out today. Thanks! :)
Answer: quadpy (a project of mine) is fully vectorized. Install with
pip install quadpy

and then do
import numpy
import quadpy

def integrand(x):
    return [numpy.sin(x), numpy.exp(x)]  # ,...

res, err = quadpy.quad(integrand, 0, 1)
print(res)
print(err)

[0.45969769 1.71828183]
[1.30995437e-20 1.14828375e-19]


Getting particles to sink and stay in solution

Question: I'm working on a project that involves finding moving particles in a solution (in my case, a syringe, or vial). The goal is to identify particles as small as 125um(micrometers), but the problem I face when I spin the container to get the particle moving, is that the particle gets stuck on the sidewall of the container, or on the top of the solution. Being that these are very small particles, I'm assuming my problem is surface tension related. The solution i'm working with is distilled water. I want to add a surfactant to reduce the surface tension, but I'm not sure what to use because I can't have bubbles forming due to the surfactant, and I need to retain the color of the solution. An idea I had was maybe some p80? Any other ideas? Also, do you think spraying the particles with a hydrophobic spray would help with anything?
Comment: Particles sticking to the sidewalls is an indication that possibly there is an adhesive force between the particle molecules and the wall molecules which is not related to surface tension.
Answer: Here are some things to try.
First, there are non-foaming surfactants available. They are commonly used in commercial floor-scrubbing machine solutions, where the presence of foam in the pump system would upset the pumping action. Many are hydrolyzable silicones.
Second, you could try agitating the test solution with ultrasonics, as in miniature jewelry-cleaning tanks for use in the home.
Third, there are surfactants which are used to prevent particles of dirt from settling out of solution & redepositing themselves once they have been dislodged from things like dishes, floors, and car bodies. These are called dispersion agents.
Comment: Thank you for that detailed answer. I don't mean to sound like i'm just trying to get all the answers to my project here but, from doing some research on non-foaming surfactants, i found a bunch, but do you know any that have a clear color to them?
Comment: Also, what would agitating the test solution with ultrasonics do? Trying to understand the physiology behind it. test solution as in the particle? or the vial?
Comment: test solution as in the vial, the ultrasound mixes the liquid inside it.


Cant connect to the router/Connection refused

Question: I found today my older router "FritzBox" (Fon Wlan 7390). I searched the web for some things i could do with my router, then I found that I can use it with my new newer "Fritzbox" and use the old as an repeater. So plugged in the electricity and a lan cable. After it booted up, I found out the router ip using /ipconfig. But as I try to connect to the interface, by browser says "Connection refused".
I can ping my router with no loss. Somebody had the same issue?
Comment: Reset the router - there will be a pin-hole button somewhere. This should let you connect...
Comment: This model doesn't have any reset funktion from outside
Comment: Can you put the model in your question?
Comment: Yes its an Fritzbox Fon Wlan 7390
Answer: I used the "emergency IP" that is universal to access the router.
Link where I found my solution.(german)
https://avm.de/service/fritzbox/fritzbox-7390/wissensdatenbank/publication/show/374_Benutzeroberflaeche-im-IP-Client-bzw-WLAN-Repeater-Betrieb-aufrufen-wenn-IP-Adresse-unbekannt/
Answer: Do you know the model of the router?
Usual first step in these situations are a reset of the router like @bigchris has said i dont know of any routers which dont include a reset button off the top of my head.
By the sounds of connection refused you have disabled local access to the router i once did that on a draytek and had to restart the configuration because there is no way of accessing it locally. Its a slim chance but you may have remote access on the router enable so you could try and find the WAN address and access it that way.
Update
I have found this thread from a couple of years ago with the same problem.

it does appear that you need to find an analog touch-tone phone and plug it into the RJ11 (telephone) port on the device and dial those keys to reset it to factory default if you do not have the password (the manual states that it cannot be recovered without factory reset).

credit to @gravyface
How to reset a Fritz!Box DSL router to factory settings?
Second Solution

2 interface via "emergency IP"preparations
Disconnect all network cables from the LAN ports of the FRITZ! Box.
Press the WLAN button on the FRITZ! Box to turn off the WLAN radio network.
The wireless LED starts blinking. Once the WLAN LED goes out, the WLAN radio network is turned off.
Connect a computer via a network cable to a LAN port of the FRITZ! Box.
Call FRITZ! Box
Call the connected with the FRITZ! Box computer on the Internet browser's address  169.254.1.1 on.
If the user interface of the FRITZ! Box does not display:
Assign the network adapter that is connected to the FRITZ! Box, the IP address 169.254.1.2 .
Call the connected with the FRITZ! Box computer on the Internet browser again, >the address  169.254.1.1 on.

Source https://avm.de/service/fritzbox/fritzbox-7390/wissensdatenbank/publication/show/374_Benutzeroberflaeche-im-IP-Client-bzw-WLAN-Repeater-Betrieb-aufrufen-wenn-IP-Adresse-unbekannt/
Comment: You're right, but I cant use my phone cause no phone is longer set up.
I found something at myself.
Its called like Fritzbox emergency IP
Its allways "169.254.1.1"
Here's the link, but it's in german https://avm.de/service/fritzbox/fritzbox-7390/wissensdatenbank/publication/show/374_Benutzeroberflaeche-im-IP-Client-bzw-WLAN-Repeater-Betrieb-aufrufen-wenn-IP-Adresse-unbekannt/
Answer: What I did and It worked is to change the static IP address on the device you're trying to access to. Also, make sure the port to the device is used. For example, you change 10.0.0.1 to 10.0.0.2. If it's still not working, try changing it again. The port number is default to be 80, however, it can be different. If different for example http port is 81, you can simply have the address to be 10.0.0.1:81.
Have a good day.
Comment: Perhaps you and I understand the question totally differently. I understand the question to be asking how to establish a connection to a device that has no external user interface except for a power switch and maybe a carefully hidden reset button. Can you explain how to change the IP address of a device that you can't login to?


Modal Popup in IE submit button does not work

Question: We are using the Ctools modal popup for registration.  In every other browser, this works.
In IE8 and IE9, after filling out the popup form, when a user presses "Create Account", the form disappears, and then pops back with all the fields empty.  In other browsers, it reroutes to the registration page.
I tried debugging in F12 developer tools but I'm not sure where to look.
Answer: Have a look at http://drupal.org/node/1549934 for a potential fix.


Make items on an armor stand's head invisible?

Question: How do I make an item that is on a armor stand's head invisible, but able to be seen by specific teams.  If an armor stand is invisible, any items in its slots is visible.  I want to have the items invisible to some players, but visible to other players.  Is this possible?  If any of this is unclear or you have any questions, please let me know.
Comment: Depending on now you are utilizing this you could try only have it show if a certain team is around - of course that means that someone else might see it though
Answer: I don't have a full answer, but I know for sure that this is not possible in vanilla Minecraft.
Invisibility is controlled by the entity to make invisible, and is not configurable per player or per team.
The only way to make an entity invisible is to give it the Invisibility effect, or for armour stands, set its Invisibility data tag to 1b.
You may want to consider downloading some mods/data packs, or creating your own. I'm not an expert at that, so I'm not the right person to ask for the job. You can look into these topics or wait for the next answer.

Make items on an armor stand’s head invisible?


Separating a desktop application into a client-server application

Question: I have a multi-tiered desktop application with a well separated modular design. So far it has been working on a single PC, but now the scope was revised to create a distributed system with a server and multiple clients on a local network.
The Client requests historical data as well as real-time data updates by subscribing to various channels.
The Server read the historical data from the database and real-time data from the PLC and sends it to a client. If a client performs any data modifications, the server must notify all the connected clients of any changes.
I have looked into WCF as well as this article: http://www.codeproject.com/KB/IP/TCPServClntCommRMIFrmwrk.aspx
Does anybody have any other recommendations on how to approach this task?
Comment: Wow, that's a nice article on codeproject :)
Answer: You are describing a typical Client-Server Model with Publish-Subscribe Paradigm. Look at the articles to get more insight to how similar architectural problems are approached.


How to get virtualenv for compiled python (missing pip/easy_install)?

Question: To update an old system I had to compile python 2.7.14 with custom openssl version. The compiled system has no virtualenv binary and also neither pip nor easy_install for extension. How can I get virtualenv for the compiled version? How about pip?
Answer: From the docs on installing packages at https://packaging.python.org/tutorials/installing-packages/#ensure-you-can-run-pip-from-the-command-line there is a section on ensuring pip by running
/path_to_compiled_python/bin/python -m ensurepip --default-pip

which will install pip. You can then use it to install the virtualenv package with
/path_to_compiled_python/bin/pip install virtualenv

Answer: The steps that helped to setup a custom version of Python with a virtual environment without doing system wide installation.
Install dependencies:
sudo apt update
sudo apt install libssl-dev openssl g++ # and possibly more.

Get Python and build it:
wget https://www.python.org/ftp/python/3.8.8/Python-3.8.8.tgz
tar xzvf Python-3.8.8.tgz
cd Python-3.8.8
./configure
make

Install "pip" to "~/.local/lib/python3.8/site-packages":
./python -m ensurepip --default-pip
./python -m pip install --upgrade pip

Setup the virtual environment:
# Creates a directory "./python3.8-env".
./python -m venv python3.8-env

Activate the virtual environment and install other packages.
source python3.8-env/bin/activate
pip install --upgrade pip
pip install <package>


what is the difference between Device driver and kernel module

Question: i know that driver is a software that can communicate with the hardware in order to control the device that attached to the computer.whereas kernel module is a small piece of code that can inserted into the kernel to improve the performance of the kernel.
I want to ask how do the driver work together with the kernel and what is the main difference between device driver and kernel module,also how do they work?
Answer: Weeeeellll.....
A kernel module is something very specific: A part of the kernel that's being loaded as a module (i.e. dynamically), after the core kernel starts. That can be anything.
In order to use the hardware you need some parts that reside in the mostly kernel for two reasons:

In order to be able to perform hardware operations that cannot be done or are impractical in userspace, or to be able to keep state outside of a process scope.
Because it would be really really inefficient to do in userspace

In order to manage most hardware you need a kernel-space counterpart. This can be compiled as part of the kernel or as a module that gets loaded later on-demand. With modules one is able not to load all of them.
But modules don't have to be related to hardware only. There are modules that just add functionality like (e.g.) ipv6, firewalling options, etc.
A Driver on the other hand is something that provides easy access to the hardware in general. It usually incorporates all hardware-specific things and exposes a generic API. And by generic I mean something that's generic-enough but not necessarily global or standard. E.g. a driver for ATI graphics cards will expose a common API for all ATI cards, but it may not be the same as other cards.
Drivers can be made in userspace, in kernel (built-in or module) or can have legs at both ends. For example, nowdays' graphics card drivers have a part in the kernel and a part in userspace (e.g. the X server, DRI, etc)
Answer: A module is just a bunch of code that can be loaded into Linux.
In Linux:-
Frequently, modules will be device drivers (i.e.) the software that drives some specific piece of hardware (device). However there are drivers and modules that don't drive hardware. for example, some Linux systems may have IPv6 support as a loadable module. Or file systems such as ISO-9660 may be drivers or modules.
For more details:-
http://www.cs.umsl.edu/~sanjiv/classes/cs5780/lectures/kernel.pdf


What exactly happens, step by step, in string harmonics?

Question: I know that a string when plucked shows harmonics but I do not really understand how. Like, I understand resonating air column and how standing waves are formed there, but I can't seem to get the step by step process of what happens in a string plucked at some point on it. Does the string produce a pulse which propagates and reflects? That doesn't seem to be the case to me. Does the plucked part keep oscillating between crests and troughs? But as far as I know, it will cause the amplitude to increase and the amplitude is constant for a specific harmonic over time (please correct me if I'm wrong). What exactly causes that standing wave pattern while plucking a point $\frac 1x ^{th}$ of the length of the string (where $x$ is even)?
Comment: https://www.youtube.com/watch?v=_X72on6CSL0
Answer: Here is an easier way to think about this.
A stretched string, once excited into oscillation, will follow a sine curve as it vibrates up and down. But when you pluck a string, you snag it on your fingernail, pull it sideways into not a sine wave shape but instead a triangle shape (two straight lines of string extending to the ends with an offset in the center), and then release it.
If you perform a fourier decomposition of a triangle or sawtooth wave like this, you will discover that the triangle wave contains a family of harmonic overtones which are absent in the case of the fundamental sine wave, and these harmonics are responsible for the particular tonal quality of a plucked string.
Answer: The best way to think about string harmonics is through the "superposition principle."
The allowed harmonics (a better term is "normal mode") for a string of length $L$ fixed at both ends are of the form $$\psi_n(x)=\sin(k_nx);\quad k_n=\frac{n\pi}{L};\quad n\in \mathbb{N}\tag{A}.$$The time evolution of each of these harmonics is found using the wave equation. We have $$\Psi_n(x,t)=\psi_n(x)\times\cos(\omega_nt+\phi_n);\quad\omega_n=\frac{n\pi v}{L}\tag{B},$$ where $v$ is the speed in the wave equation.
The key argument of the superposition principle is this: if we deform the string at $t=0$ and then allow it to oscillate on its own, there exists a set of time-independent constants $c_n$ such that the state of the string at time $t$ is given by $$\Psi(x,t)=\sum_nc_n\Psi_n(x,t)\tag{C}.$$
To understand this equation, we first consider what happens if $c_1$ is nonzero, and $c_n=0$ for all other $n$. This is a familiar pure harmonic with amplitude $c_1$. Thus, the entire equation means that at every time $t$, the state of the entire string is just a the "sum" of the harmonics, each of which is oscillating independently at its own frequency; the amplitude of each harmonic is $c_n$.
We may now apply this model to the case at hand: a plucked string. We first assume that the "pluck" involves deforming the string such that at $t=0$, it is completely stationary and it takes the form $\Psi_0(x)$. This could be triangle-like if we consider the image of a stringed instrument, but it could be anything sufficiently small. Since the wave is initially stationary, we must have $\phi_n=0$ (this can be proved by considering the derivative of $\Psi_n$ with respect to $t$). Our goal is to find $c_n$ at $t=0$, then everything that the string does after that follows from the superposition principle. Considering the projection of each harmonic e have $$c_n=\int_0^L\mathrm{d}x\,\psi_n(x)\Psi_0(x)\tag{D}.$$
To summarize, if we pluck a string by moving it $\Psi_0(x)$ at $t=0$ and then letting go of it, the state of the string at any future time $t$ is given by equation (C), with variables therein defined by equations (A), (B), and (C), with $\phi_n=0$ in (B).
Numerous special cases, including the case where the string is plucked at $x=L/m$ for even $m$, can be examined by evaluating the integral in (C).

This may initially look like it's just a lot of math math, but actually deeply reflects the mechanisms of the wave propagation. The fact that equation (C) holds follows from the linearity of the wave equation for strings, which is, in turn, a result of the linear relation between the restoring force on a particle of the string and the displacement of the particle. Visual effects, like the apparent initial propagation of the pluck's perturbation, are just results of this description of time evolution. We haven't actually proved it here, but any instantaneous configuration $\Psi(x,t_0)$ that the wave could possibly take, i.e. any displacement that respects the boundary conditions, can be expressed as a weighted sum of functions given by equation (A). And since each of these $\psi_n$ must be made to evolve in agreement with the wave equation, the net evolution of the wave must follow the superposition thereof.


How to Automate UI, API, Performance & Security testing using a single Framework?

Question: How to Automate UI, API, Performance & Security testing using a single Framework. One test case should check all these things. Any suggestions?
Comment: This is an unrealistic goal for an undefined objective.
Comment: `One test case should check all those things`- why do you want to do this?
Comment: Why do you want only one framework ?
Comment: One test case will check security, performance and functionality? Can you give a real example of such case?
Answer: My solution is to pick a language, for example Ruby (a good choice imho) or Java or C# as the 'framework' for your solutions (I'm avoiding the word framework lately though, badly abused).
Then select tools based on that toolset, for example, for ruby: cucumber, rspec, minitest.
Answer: You need to choose a performance testing tool which supports all aforementioned requirements, for example take a look at Apache JMeter:

UI tests can be integrated via WebDriver Sampler
API testing is naturally supported via HTTP Request sampler, see Building a WebService Test Plan user manual entry for details.
You can use JMeter for Security Testing as well, see Security Testing With JMeter - Learn How article for several use cases
And last but not least you can kick off any external command or program via OS Process Sampler so theoretically you can integrate anything into JMeter test.
Comment: +1 for jmeter.  You can use jmeter for functional testing.  You can schedule quick diagnostic checks to ensure that your website and/or API is up and running.  One of my favorite things about jmeter is that you can setup an API test and use the exact same test for performance testing your API.  Then there is the JSR223 Processor, where you can write custom scripts using your favorite language.


What is the opposite of Love?

Question: The answer to this question will reveal the single greatest identifier of the antichrist who is the lawless one spoken of in 2 Thessalonians 2:-7.
Comment: The question has not established how, exactly, determining the opposite of love will 'identify' the lawless one (it is ανομοσ, _anomos_). And it is a matter of opinion what the opposite of love is, in any case. It could be hatred, murder, selfishness or other things. I think the question needs focus and clarity, myself to get it away from mere opinion.
Comment: Welcome to BH. Please see the Tour and the Help (below, bottom left) as to the purpose and the functioning of the site.
Comment: If loves opposite is hate, what is the best biblical example of love?
Comment: Satan and other devils his rank are evil spirits. Lesser devils are called unclean spirits, because they are not chaste. Both evilness and uncleaness are anti God. Satan will survive the end times and not succumb until the end of the millennium. The spirits of the beast and the false prophet looks like frogs, and are therefore unclean spirits.
Answer: The opposite of love is selfishness:

 So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy, 2 complete my joy by being of the same mind, having the same love, being in full accord and of one mind. 3 Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves. 4 Let each of you look not only to his own interests, but also to the interests of others. 5 Have this mind among yourselves, which is yours in Christ Jesus, 6 who, though he was in the form of God, did not count equality with God a thing to be grasped, 7 but emptied himself, by taking the form of a servant, being born in the likeness of men. 8 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross. 9 Therefore God has highly exalted him and bestowed on him the name that is above every name, 10 so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.
(Php 2:1–11, ESV)
Comment: Amen, very well put. What does this tell of the nature of the antichrist?
Comment: @Perry you might also want to quote Romans 2:7-8
Answer:
For this is the message that ye heard from the beginning, that we should love one another. Not as Cain, who was of that wicked one, and slew his brother. And wherefore slew he him? Because his own works were evil, and his brother's righteous. [1 John 3:13 KJV]

Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. [John 8:44 KJV]

The wicked one, 1 John 3:13, of whom was Cain, is here characterised by Cain's slaying of his brother.
And the devil (diabolos), John 8:44, is here characterised by, firstly, murder and, secondly, by lying (to Eve, as a means to the murder of humanity in the beginning).
I would say that the opposite of love is murder - the negation of another rather than love to that other. The emotion is hatred ; the activity is murder.

... he that hateth his brother is a murderer. [1 John 3:15 KJV]

John, here, equates the two. One might say hatred is the opposite of love, but then hatred is the same as murder. There is an equivalence between the two. They are interchangeable.
And this murderous hatred is what characterises the Wicked One who shall be manifest, on earth, in humanity, in the last times.
The murder upon which he will be intent is the murder not of humanity generally, for humanity is that which he indwells. It will be the murder of the saints, God's people, the true Church, on which he will be focused.
This is already evident in certain parts of the world, today.
Comment: @JeremySt.Germain I would not dream of attempting to describe the character of the Lord God almighty with just one word. God's attributes and characteristics are dealt with in many ways, throughout the history of scripture, by multiple (appointed and qualified) authors. We need to imbibe _all_ of that to understand, appreciate and believe in the One who is revealed in his Own word.
Comment: @JeremySt.Germain John also says that 'God is Light'. You need to bear that, also, in mind. It is also said (and repeated) that 'our God is consuming fire'. That, also, needs to be borne in mind. There is also nothing inherently wrong in self-preservation. That is why we procreate : to preserve the species. It is only when self-preservation contradicts the will and purpose of God that self-preservation becomes a sin. But that matter is resolved when 'I am crucified with Christ, nevertheless I live, yet not I, but Christ liveth in me'. Amen.
Comment: Love is John 3:16. Based on this, what one word would you use to describe the character of God, and what is the opposite of that word?
Comment: If I may share what He told me about his character that is found in John 3:16. This verse is the DNA of YHWH, it is the quintessential definition of Love and the revelation of the character of YHWH. Love is giving to the point of sacrificing self for the benefit of others. The word that most completely describes a nature such as this is, selfless. The opposite of Love then is selfishness. Selfishness is also the most defining characteristic of man due to the influence of the strongest human instinct-self preservation.
Comment: Yes indeed He is all of those things but none of those describe His character. God is Love, Love is his character and the nature of Love is to give. We don't procreate to preserve the species, we procreate to preserve our own genetic heritage-self preservation. This instinct always opposes the will and purpose of God. Scripture says in Romans 8:7 the flesh is enmity against God, this is the source of the carnal mind. It is rooted in self preservation, here is where you find the very worst of humanity. Greed, corruption, gluttony, fear etc...
Comment: @JeremySt.Germain On this site, as you will see in the Tour and Help, comments are not for prolonged discussion, so I will not further comment. There is a chat facility to permit private discussions.

What is the opposite of Love?


Raspberry Pi or Similar to Go

Question: This question might be too broad, but I need a starting Point. I'm trying to find a little computer that can run with a battery for at least 24h, just using the cpu + wifi. Is raspberry suited for that or are there any better options? I basically want to use it as a control unit, to control other devices and log information in realtime. (For Filmsets)
Comment: You need to decide WHAT you actually want to do - you could probably do this with an Arduino.
Comment: You haven't given nearly enough information here for someone to give you any kind of a valid answer. What kind of task is this going to complete? What sized battery?
Answer: I think Pi is suitable for your need

Low power comsumption
Pi 2/3's CPU is enough for your tasks

I recommend you to try Pi Zero Wireless or Banana/Nano/Orange Pi from other manufacturers.
Comment: Oh that looks interesting, didn't know about the Pi Zero Wireless
Answer: Yes, try Pi Zero W. I have used it with my 10000 mAH battery pack and it ran for well over a day.
Answer: Another vote for Pi Zero W.
I have one here that I just measured that takes 80ma at idle, so 1920mah in 24hrs.
But note that you can't get the onboard wifi to act as an access point. To make an access point you can use a non-W zero and a supported USB wifi device.
I've just measured a Pi Zero with usb wifi and it idles at 100ma, though jumps to 160ma when I ping it!
Also note that a Pi won't cope with anything that is rapidly changing.
Eg I receive data from wireless thermometers as a bitstream but had to use an arduino to do that. The arduino does the receiving and decoding (and that is all it does) and then passes it to a Pi Zero which is the brains of the operation.

Raspberry Pi or Similar to Go


Linux crashed menu access

Question: I pressed the key combination ctrl + PrtSc on my Ubuntu with a browser window open, and it just crashed gnome. How can I get my system back without restarting the machine?
Answer: Press Alt + F2 which brings up the "Run" dialog, enter the letter r (which stands for "restart") and then press Enter:

This will restart Gnome without affecting your session or restarting your machine.

Linux crashed menu access


In Apple Mail, is there a keyboard command to shift focus from a message to the message list

Question: In my usual review of email, I have the message preview pane open and use the keyboard to delete, archive, or skip messages with the focus in the message list.  Sometimes I want to click a link in in an email.  When I'm finished with that, I usually switch back to Mail using ⌘-Tab.  In that case it takes a mouse/trackpad gesture to put the focus back in the message list.  Normally, I would expect to be able to use ⌥-Tab to shift focus between the panes, but instead, the focus moves to individual items in the toolbar and skips the message list.  What am I missing?
Answer: You can enable Favorites bar where each element has shorcuts like ⌘1, going from 1 to 9. When you keystroke shortcut of an inbox its message list gets focus.
If you have multiple mail accunts you have to use corresponding shortcut for each inbox. This is not as ergonomic as a single shortcut would be though.
Comment: This would be useful if I looked at each account separately, but there are a couple of barriers to using the favorites shortcuts in my workflow.  (1) I have one viewer window open to a single work account and another open to two personal accounts: iCloud and gmail. Use of ⌘-1 changes the mailbox of the current window.  (2) for whatever reason, ⌘-2 for gmail is greyed out, and there is no ⌘-3 for iCloud.
Answer: On macOS Mojave, tab cycles between Mailbox list, message list, message and search bar.
Answer: I've recently discovered that you can shift focus from a message to the message list with an awkward combination of two repetitions of ⇧⌥-Tab then ⌥-Tab.  I.e. you can't "back up" to the message list; rather, you have to shift focus to it in the "forward" direction.  It seems like there should be a better way to do this in a single keystroke.  If anyone knows a better keystroke or shortcut, I'd love to hear it.


how to disable ./watchbog process

Question: ./watchbog is using up 198% of my cpu processor and mem 52%. Solar is the user. I tried stopping solar service but of no use. Watchbog is still running and using up as much space.
Comment: Did you try executing this `echo '0' > /proc/sys/kernel/nmi_watchdog` as a root user.
Comment: thank you for your response ,
Comment: If your server has been hacked you need to do more than stopping the offending process.
Answer: 'watchbog' is a crypto miner stager which sets up xmrig on the system.
There is a guide written on how to remove a common instance of it here. This does not mean the procedure to remove yours will be exactly the same, but the guide will definitely be of assistance.
It sounds like your system has been breached. Stopping this process is not going to keep it from coming back in the long run. I suggest employing a firewall, checking for unknown listener sockets, and newly added authentication keys that do not belong.
Comment: thank you for your response.
Answer: Last time my VPS also got this problem. When run, see using top or PS and check which user that run it. After that you can see the cron of the user either using crontab -e or on /etc/cron.X/user or on /var/spool/cron and clean it. If it's not cleaned, find again where's the file belong, as far as I know, watchbog that I encountered is using curl to run it's process. Last time I uninstall curl first and clean the cron then wait a while, also don't forget to change the user password that's breached. When watchbog come into your system, it means some of your user password compromised and if your server have public ssh server then try to block user that brute force to login using fail2ban.
Comment: thank you, i find the same
Answer: Here is what I did to remove the Watchblog virus:
I found watchbog virus in one of my linux machine and here is what I did step by step that I finally manage to kill the virus. The virus is having a hidden process that create cronjob and use up the CPU. This can be detected by the following command:
ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
%CPU   PID USER     COMMAND
198.2%  8128 root     ./watchbog
31.5  8116 root     ./watchbog
31.4  8140 root     ./watchbog

So what to do? First, check the content of the crontab:
crontab -l

#
Thus,if there any cronjob unverify, the virus is automatically creating crontab. We can remove the crontab using the following command:
crontab –r

Then we can check if it is already empty using the following command:
ls /var/spool/cron/crontabs

Then, we remove the cron job and then kill the process.
crontab -r while true ; do killall watchbog ; done

Let us see again if it works.
crontab -l ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10

There is no more watchbog.
Then do not forget to change the password
sudo passwd root

how to disable ./watchbog process


Radio buttons with Paginator (CakePHP)

Question: I want to have a paginated list in a table and a radio button for each record.
I looked everywhere and I couldn't find anything. I know how to do this with checkbox (simply adding $this->Form->input('id', array('type' => 'checkbox')); of course) but it doesn't work when I change checkbox to 'radio'. It seems that radio needs an array as options.
I wonder if there's a way of doing something like this?
Answer: I guess you loop over the data to create the rows of the table. You'll have to create the radio inputs manually by typing the html then because the HtmlHelper can't know about that you're looping over the data and is not aware of the actual row. If I'm wrong: show the code.

Radio buttons with Paginator (CakePHP)


How to create an email address for a group in Gmail

Question: How do you create an email address that contains a group of other emails (in Gmail) E.g., when I send an email to firstname.lastname@example.com to go to firstname.lastname@example.com and firstname.lastname@example.com?
Answer: You can't do what you're thinking in the "normal" (consumer) Gmail. (What you want is possible with Google Apps Email, but I assume that's not what you're talking about.)
You can create a contact group in your Contacts that will make it easy to find and send email to multiple people, but ultimately it just adds all of their email addresses to the To: field. Just go to your Contacts (from the menu in Gmail or at http://contacts.google.com) and create a Group.
Your other alternative is to use a mailing list system like Google Groups. That offers you a way to have one email address that sends messages in turn to multiple email addresses, but it'll be in the form of email@example.com.


Can I abandon abusive parents?

Question: My father provides us everything he can but he is verbally abusive. To a point where I have zero respect for him and zero interest in interacting with him. What does Islam say about abusive parents?
Comment: If possible try to improve your relationship. If your dad is verbally abusive try teaching him that is bad and control your anger. Just make sure that even though he disrespects you you do not do the same to him.
Answer: In the name of Allah, the Most Gracious, Most Merciful
If he is truly abusive, then remind him of this verse in which Allah said:

"O you who have believed, protect yourselves and your families from a Fire whose fuel is people and stones, over which are [appointed] angels, harsh and severe; they do not disobey Allah in what He commands them but do what they are commanded." [Quran, 66:6]

And also tell your dad that if he don't quit being abusive, then angels of torment will awaits you to torture you in Hell and they don't disobey the command of Allah. So that he may stop being abusive towards you.
And as for you, Allah says:

"And your Lord has decreed that you not worship except Him, and to parents, good treatment. Whether one or both of them reach old age [while] with you, say not to them [so much as], "uff," and do not repel them but speak to them a noble word." [The Night Journey, 17:23]

Tips of how you can deal with your father

Forgive him [al Maida, 5:13]
Show him that you're better than him
show him kindness and goodness greater than his

But, if you dare to abandon your parents, then Paradise will be closed upon you because you have not fulfilled the duties which God made obligatory upon every kid.
Also, there is a severe punishment if you abandon your parents because of abusing you.
Allah said:

"So would you perhaps, if you turned away, cause corruption on earth and sever your [ties of] relationship? Those [who do so] are the ones that Allah has cursed, so He deafened them and blinded their vision..." chapter Muhammad
Jubair b. Mut'im reported on the authority of his father that Allah's Messenger (ﷺ) said:
  The severer would not enter Paradise. Ibn Umar said that Sufyan (explained it as): One who severs the tie of kinship would not enter Paradise. [Sahih Muslim, 2556]

Some narrations which encourages you to do good:

Abu Huraira reported that a person said:
  Allah's Messenger, I have relatives with whom I try, to have close relationship, but they sever (this relation). I treat them well, but they treat me ill. I am sweet to them but they are harsh towards me. Upon this he (the Holy Prophet) said: If it is so as you say, then you in fact throw hot ashes (upon their faces) and there would always remain with you on behalf of Allah (an Angel to support you) who would keep you dominant over them so long as you adhere to this (path of righteousness). [Sahih Muslim 2558]

Those who cut the ties of kinship deny themselves the reward for upholding the ties of kinship in the Hereafter, in addition to denying themselves much good in this world, which is a long life and ample provision (as we mentioned in a previous Hadith): that the Prophet (sal Allahu alaihi wa sallam) said: "Whoever would like his provision to be increased and his life to be extended, should uphold the ties of kinship." [Sahih Al-Bukhari and Sahih Muslim]

So, do you wish a long life with too many provisions from Allah? Then, don't abandon your parents even if they abuse you.
CONCLUSION: I have not found any report from Sunnah of Prophet in which he allows the cutting of ties with parents. I have made researches and found that the Prophet encourages you to not abandon your father even if he abuse you, otherwise if you do abandon your parents, then you will have a terrible life and a terrible Day. So based on my researches, it is haram whatsoever for you to abandon your abusive parents. The wisest thing you can do is just forgive your dad and give him good treatment and be kind with him and don't mind what he does to you if you find abusive.
Comment: Peace Alex, Re "But, if you dare to abandon your parents, then Paradise will be closed upon you because you have not fulfilled the duties which God made obligatory upon every kid."..., there's no way you can know this. What do you think Abraham did?
Comment: @rahi Well, as far as I know, Abraham did not abandoned his parents.
Comment: Al'hamdulilah. What about the context of chapter 60, and particularly 60:4? However, you're right. We know Abraham and his dad didn't get along, but the Quran refers to emigration away from hostile environments. Right?
Comment: @rahi I have read just now that verse and my opinion is that Abraham was free from shirk and he was absolute Islamic monotheist man alongside with his followers. But still he did not abandoned his father, because in that verse it shows that Abraham loved his father so much at he wanted to pray for his forgiveness. But even if he is free from shirk, still he did not abandoned his father unless he was abusive, but I doubt that he was abusive father.
Comment: ✌ 19:44 to 19:50 clearly shows you that Abraham's father was abusive, *and* that Abraham abandoned him.
Comment: @rahi Sorry, I didn't had to look through it. I had homework to do. Well, I think I have misunderstood it and wrote things that are out of context.
Comment: Thanks for letting me know. I hope you are able to revise the misleading bits from your answer considering the evidence from the Quran. Peace, with God's special mercies and blessings.
Comment: @rahi hey bro, I didn't meant to mislead anyone, I only thought that I did according to Sunnah and Quran. But, thanx for opening my eyes and made me realize that I made a misleading answer. Anyways, you can give me a dislike.
Answer: Peace, from the source of peace. I am sorry to hear about your poor relationship with your father. Does not sound pleasant.
Prophet Abraham is certainly one example of a person who abandoned his dad. However, it took a fair bit of frustration and really crimes against Abraham before cutting ties with his dad.
Parents are a big deal in the Quran. Simply no doubt about it. Therefore, seeking avenues to remedy the relationship ought to be exhausted before you consider abandoning them. Indeed, life without parents have lots of challenges you may not be aware of yet.
That said, and paraphrasing into English, God says:

29:8: And We instructed the human being to be good to his parents. But if they strive to make you set up partners with Me, then do not obey them. To Me are all your destinies, and I will inform you of what you used to do.

God is giving you explicit permission to disobey your parents if they're getting in the way of you cultivating a relationship with God.
and

4:135: O you who believe, stand with justice as witnesses to God, even if against yourselves, or the parents or the relatives. Even if he be rich or poor, God is more worthy of them, so do not follow desire into being unjust. And if you twist or turn away, then God is Expert over what you do.

God is basically giving you the license to disobey your parents if it is for a just cause. You can watch for that the next time you hear foul language from your father. You can push back firmly on a justice front. You can ask "is it fair to say ?" for example. Obviously use your discretion.
However, these words from God, again paraphrasing in English, truly makes the poor choice of words from your dad an issue, which with God's help, you can try and raise

68:7: Your Lord is fully aware of those who strayed off His path, and He is fully aware of those who are guided.
68:8: So do not obey those who deny.
68:9: They wish that you compromise, so they too can compromise.
68:10: And do not obey every lowly swearer.
68:11: A slanderer, a backbiter.
68:12: Forbidder of charity, a transgressor, a sinner.
68:13: Unappreciative, and greedy.

68:10 in particular is a characteristic you're witnessing in your dad. That's unfortunate.
Bottom line
Abandoning parents can open up a whole other set of problems you didn't anticipate. However, enduring verbal abuse is not a virtue.
If there's a good time to speak with you dad, maybe when he's less stressed, perhaps talk to him about it. Tell him to cut it out or drastically reduce it. Tell him that it's affecting your relationship with him.
Tell him the truth, and encourage him towards it, as God advises us to

103:1: By time.
103:2: The human being is indeed in loss.
103:3: Except those who believe, and do good works, and support one another with the truth, and support one another with perseverance.

May God ease your hardships in this part of your journey.
Answer: I can fully relate to your predicament of abuse.  My father a devout muslim prays five times a day, fasts, gives to charity etc. But he is not only verbally abusive but physically abusive as well.  He ran our home like a Dictator and often would assault my mother and us, often to no fault of ours mostly for just having a bad day.  It was not uncommon for him to leave the house without saying where he was going because he was above telling a woman his whereabouts.  In a fit of rage during an argument over dinner my father would lose his temper and take all the food and wipe it off the table and it would go every which way on the walls, floor and ceiling.  He made us all walk on eggshells and your opinion was of no significance.  Until today almost at 50 still I suffer from anxiety mostly from retriggering whenever I am in his presence or on the phone.  He is one to put everyone down in his family especially his wife and children and loves to tell us how hell will be full of woman.  I have tried to keep communication with them through the years and one thing is for sure my quality of life has been affected.  Suffered with low self-esteem and found it difficult to interact with others as would hear the negative verbal confirmations of both my parents in my head.
If we were back in our home country I could have turned to an aunt, grandmother, uncle anyone who could have interjected but being in a foreign land away from family you are left flailing.  My grandmother upon her visit said that my grandfather never ever hit her and she did not know where this behavior is coming from. My grandmother on my mothers side said to divorce him within the first year as he slapped my mother across the face for asking him why he was late for dinner.
If one of Allahs description is the Just, how can this injustice be considered ok.  If he is the God of Mercy, again why would he allow this to continue.  We as a muslim community have a responsibility to our Ummah to keep its children safe and to teach respect toward the spouse.  We should have confidential counselling centers to address these concerns.  We are very fragmented and alone when there is a problem.  If no one is advising my father then he is left without putting himself in check.  There are hadiths stating the prophet never layed his hands on a woman or servant are they not worth mentioning.  Or the one where the prophet was praying an a child crawled on top of him, and instead of yelling stopped his praying to play with a child and then resumed his prayer.  He could have scolded the child and destroyed his spirit.  Islam is a religion of everyday conduct and parents as they have a right over their children their children also have rights.
Life is harder than ever we no longer have the tribe to support us.  Wars have also warped many of our muslim brothers minds as my father was bombed twice in his life once as a child and the other during war. In addition, behavior is learned and we are expected to be kind without experiencing kindness.  Seems like taking a test without knowing what will be on it.  We have a new world problem that isn't being addressed and the trickle down to their families is having a very real and lasting affect. Yes, be kind to your parents but the child even an adult child only has so much power and may also be psychologically suffering.  Try your best, ignore their comments, limit your interaction if need be but there is a point where you may have to decide whether the verbal abuse is Islamic, several hadiths on that as well comparing those that are loud to a braying donkey and slanderous foul language as being held in contempt in the eyes of Allah.
Comment: Salam and welcome to IslamSE the Q&A site about Islam. Please don't confound us with a typical internet forum. We are not sharing life experience nor are we a peer support group. For further information take the [tour] and check our [help].

Can I abandon abusive parents?


How do I find a renamed wallet whose name I can't remember?

Question: I bought BTC in 2011 and renamed my wallet.dat to something else that I cannot remember. How can I find my wallet file on my computer? I'm prepared to use the command line and scripting.
Comment: What operating system are you using?
Comment: I'm using Windows 7.
Answer: Place to start - use the linux "file" command, which will show the following for a bitcoin wallet (at least in the client I use)
wallet.dat: Berkeley DB (Btree, version 9, native byte-order)
So - you could run something like:
find / -type f exec file '{U}' \; | grep "Berkeley DB"
That would be a start!
Comment: This worked for me: `find / -type f | xargs file | grep "Berkeley DB (Btree, version 9, native byte-order)"`
Comment: My wallet file is on Windows 7.  I don't use Linux. :(
Comment: Well - you could install "cygwin" and execute the command there (it's more or less a linux environment for windows) - or you could figure out the header and paste it into the "content" part of the Windows search.

Or you could boot from a linux LiveCD / LiveUSB!
Answer: In Windows 7 download and install Altap Salamander 2.54 (Google for it)
It's file manager (you can use any other file manager as well)
Then press Ctrl and key F to bring search window
Then set all options exactly as in this screen: http://s21.postimg.org/5qdx5cb1j/search.png
In Containing field enter: name"1 (each wallet has this text inside) and then click: Find Now
It takes a while to search entire disc C:
To speed up the process You can setup also Advanced options - see this screen: http://s21.postimg.org/xzb01t1wn/advanced.png
(I presume that Your wallet size is from 30KB to 10MB. If not change second value)
Comment: Thanks for your comment.  I noticed your png file shows search results only ending in .dat.  I believe I renamed my wallet file something innocuous like config.sys.  In that scenario, will the Find function still find the wallet file, or does it depend on the extension ending in .dat?  Also, if I find it I WILL tip you, not sure why you edited that comment out. :) You'd deserve it.
Answer: Write a script (e.g. Perl, Python, Ruby... ) that opens every file on your computer and looks inside it to check the format.  I'm not sure what that format is exactly.  It may be as simple as a certain constant sequence of bytes at the beginning (a so-called "magic number").
Comment: How do I "check the format".  I can write scripts but I have no idea how to do those 3 words, "check the format".
Comment: First you have to find out what the wallet.dat format is... is there a "magic number" at the beginning that identifies it?  Many file formats have such a magic number.  If so, your script must open each file in binary reading mode and read the length of bytes that would be in the magic number and see if it matches the particular bytes for the wallet.dat magic number. You may be able to use PyWallet (https://en.bitcoin.it/wiki/Pywallet) as a helper from your script.  Or at least you could look at the source for Pywallet to see if there are any clues about the existence of a magic number.