"What library can I use to do X?" type of questions are not welcome on Stack Overflow, right?  Even if they are not welcome on SO proper, is there any other SE board where I could ask such questions?
I have a list of requirements for a program, but I don't know what program meets these criteria. That's about general-purpose software, for example, not a programming IDE or statistical workbench, questions about which would certainly go to respective sites.  Is this question appropriate on Stack Overflow? Where should I ask about it? On Super User or elsewhere?
Getting secondary citations right I have some questions regarding secondary citations (in an computer-science research paper that should be published in a journal). I know that they should be avoided when possible, but it is not always that easy. More specifically, my situation is this:  Article A says:     The average value of ... in ... is ... [B]. [C]’s study says that in ... the value is ...   This statement is exactly what i need for my paper. If I read [B] and [C], I see that [A] cited them correctly and if I would have found these two other articles myself, I would have written the same.  Now how to cite this in a correct way?      [B] and [C] say (cited in [A]) ...   and do a “bad” secondary quote;    [B] and [C] say ...   and neglect the investigation done by [A] and peform citation plagiarism;    [A] says ...   and neglect that the data was the achievement of [B] and [C].    [A] says based on the findings of [B] and [C] ...   and do a secondary quote again. At the end of a makefile I saw   rm -f *~ *.class   I understand the *.class, but what's *~? biblatex - issue number of journal in date Option clash for package xcolor Why is "chmod -R 777 /" destructive? This is a  about File Permission and Why 777 is "destructive".   I'm not asking how to fix this problem, as there are a ton of references of that already on Server Fault (reinstall OS). Why does it do anything destructive at all?  If you've ever ran this command you pretty much immediately destroy your operating system. I'm not clear why removing restrictions has any impact on existing processes. For example, if I don't have read access to something and after a quick mistype in the terminal suddenly I now have access well... why does that cause Linux to break? Prove that $PSL(2,\mathbb{Z})$ is free product of $C_2$ and $C_3$ Prove that $PSL(2,\mathbb{Z})=C_2 \star C_3$.  Now $C_2 \star C_3=\langle a,b\ |\ a^2, b^3 \rangle$ i.e. the free product.  But how do I show that presentation of $PSL(2,\mathbb{Z})$ is this? An .mov video that is upside down in Windows appears right side up in OSX Can Excel show a formula and its result simultaneously? Remove Meta Privilege for MSE (only) What I am asking here is to please remove the privilege to participate in Meta for MSE.  This privilege is literally useless. You can't really have a meta site for a meta site. There's no Meta.Meta.SE here or any other SE site out there: Meta.SE covers for every site in SE, including itself.     When users find out that you don't really get anything new, it's kinda sad for those people. There is no use for it except just to be there and fill up the space between the first and third privilege. Privileges should be shown only if you earn something new, and this privilege to participate in the meta isn't new because it's where you report problems in all of SE, including Meta.SE.    So please remove the privilege to participate in meta just for Meta.SE.    This is not a dupe as this is a feature-request to remove it, not support on why it is there. Counting the occurrences / frequency of array elements Can you run Android in a VM on PC? I came across a how-to guide for running Android 1.7 in a virtual machine (VirtualBox), but 1.7 is old. I haven't been able to find a Android 2.2 or 2.3 image anywhere, does anyone have any ideas on how to virtualize newer Android OS's? Preferably a free virtualization solution like VirtualBox.  Here is the link about virtualizing 1.7:    They send you to here to download Android disk images:    But I can't find anything newer than 1.7, anyone have any ideas? Our production server (2012, VM + SAN) has 32 GB of RAM, the database size is ~80GB. The application uses TempDB heavily - disk is hit ~100 MBps both reads &amp; writes.  Seeing tons of SQL compilations/sec .. 95% of all batch requests are compilations.  Ideally would like to increase the RAM to 64GB or 128GB, but need to 'prove' to team that it's required.  Buffer Cache Hit Ratio (BCHR) is 99.9%, but Page Life Expectancy (PLE) is only ~400. What's the explanation for this ? I though PLE &amp; BCHR had a linear relationship (i.e. they increase or decrease together)  On other VMs with larger databases and lot more RAM, both BCHR &amp; PLE are high.  Current wait stats and perf counters Incompatible pointer type initializing 'CustomCellView *' with an expression of type UItableViewCell I know there are some similar posts on adding review queues to the mobile web page. However, this is regarding the Stack Exchange Android app. I really would like to review posts and edits from the Android app, however this isn't included in the app yet. I'm not sure how it would be implemented; maybe there could be a button or something for review. Could we please see this? Travelling to India via Germany with 2 stops, do i need transit visa? I have Indian passport and USA H1 valid visa, will be travelling US and my itinerary is Mumbai – Munich – Frankfurt – San Francisco. This route has two stops in Germany, Munich – Frankfurt is German domestic flight. I am not sure if I would need a Schengen or Transit Visa. I was going through few German and Indian consulate visa website but I am not able to get the correct info, specially below two statements are confusing. Could you please help me with this?    In these five airports in Germany you can stay at the International Transit Area without a visa: 1.  Cologne/Bonn 2.  Düsseldorf 3.  Frankfurt/Main 4.  Hamburg  5.  Munich  Airport transit privilege does not apply in the following cases and you will need to get a visitor visa if: You are transiting through two or more airports in the Schengen Countries How to use a proxy on the command line? I can set my proxy username and password along with proxy settings in the proxy ui but these settings do not work on the command line. How can I use apps such as wget &amp; ping on the command line with a proxy?  Example Details:   username: 1234 pass: linux proxy: proxy port: 8080 How can I sort arrays and data in PHP? Why do you need to change your position rather than just focal length to affect perspective? Why must you change your distance from an object to change your perspective of it? Why is it not sufficient to change the focal length of your lens (the zoom level) to change  your perspective? How do I get a remote host IP address if I don't have ping, and don't have any bind utilities like dig, nslookup, etc?  I need an answer that does not include 'install X' or 'use sidecar container'. I am looking for something that relies on nothing more than bash and the basic shell commands. Class of sets of a given infinite cardinality This question was inspired by the question on .  From the discussion in the comments there, it seems there does not exist a set of all sets of a given cardinality.  To me, it seems easy to see that this is true for any nonzero finite cardinality $n$. Given any set $x$, you can always make a set of size $n$ by adding $n-1$ other sets to $x$ to make a set of size $n$, which exists by repeated use of the pairing axiom.   But how would you do this for infinite cardinalities? For suppose $\kappa$ is some given infinite cardinality. To show that the set of all sets of cardinality $\kappa$ does not exist, it seems you would have to show that for any set $x$, there exists a set of that size with $x$ as an element, and then you could take the union of that set to find the set of all sets, and thus a contradiction. But it doesn't seem reasonable to simply say, for a given set of size $\kappa$ if $x$ is in the set, we have no problem. If not, just take an element out of the set and put $x$ in. Something about that seems like it would not be allowed.  So how would you do this for infinite cardinalities?