systemd - how to power on USB drive?
How to reconnect a logically disconnected USB device?
Do resistances stack? If a creature had resistance to spells, and then cast fire resistance on it, would it take only 1/4 damage from all fire spells? How does reflection work? When quoting something said by someone else, should I use a comma before the quote? Suppose I quote the definition given in a dictionary. Am I correctly using the the punctuation marks in the following sentences? (I am using them in the way I think correct in American English.)     One of the meanings of cat is, "a small animal with soft fur that people often keep as a pet."        A cadet is, "a young person who is training to become an officer in the police or armed forces."   Should I use a comma only when I explicitly quote somebody?     Groucho Marx once said, "Although it is generally known, I think it's about time to announce that I was born at a very early age."   Should I use a comma in this case too?     As Groucho Marx said,            No one is completely unhappy at the failure of his best friend.      On Comma Sense, A fun-damental guide to punctuation (Richard Lederer and John Shore), I read the following about using the comma:     Use commas to set off complete quotations:           The great general George S. Patton once said, "No, no—the war is this way, you idiots!" What i did?   [root@mdfdevha1 ~]# Group_ID=`/opt/keycloak/bin/kcadm.sh get groups -r TEST`  [root@mdfdevha1 ~]# echo $Group_ID [ { "id" : "57c86153-11ba-4d19-aafb-9903ee00086b", "name" : "Admin_UserGroup", "path" : "/Admin_UserGroup", "subGroups" : [ ] } ] [root@mdfdevha1 ~]# SURE_USER_ID=`echo $Group_ID | cut -d : -f2 | awk -F\" '{print $2}'` [root@mdfdevha1 ~]# echo $SURE_USER_ID 57c86153-11ba-4d19-aafb-9903ee00086b   In this case i am able to get the id but my requirement little bit complex  I run below command   [root@mdfdevha1 ~]#  Group_ID=`/opt/keycloak/bin/kcadm.sh get groups -r My_Realm`   and then   [root@mdfdevha1 ~]# echo $Group_ID   Output was multiple record in JSON format  [ { "id" : "e27206c0-aeb6-43db-acda-c4ba43233071", "name" : "A1", "path" : "/A1", "subGroups" : [ ] },  { "id" : "89f3bd6a-33a9-4e02-9fe3-eae660c5a6cf", "name" : "Admin_UserGroup", "path" : "/Admin_UserGroup", "subGroups" : [ ] },  { "id" : "cdc2bce5-c3bb-4b88-bdaf-d87b8bb6c644", "name" : "Group104", "path" : "/Group104", "subGroups" : [ ] },  { "id" : "a0d749f2-ab6c-4c27-ad55-3357eaab9527", "name" : "Group105", "path" : "/Group105", "subGroups" : [ ] },  { "id" : "fbf99c34-d50d-408b-8d19-9713f9af3e3a", "name" : "Group106", "path" : "/Group106", "subGroups" : [ ] },  { "id" : "ebd8336f-4017-4fb1-8035-153ae1d9ba37", "name" : "Group201", "path" : "/Group201", "subGroups" : [ ] },  { "id" : "38f4aef7-caf0-4430-9e61-1ae7026e872f", "name" : "Group202", "path" : "/Group202", "subGroups" : [ ] },  { "id" : "436a0f4a-8b1b-4d7d-a014-fcec3513644e", "name" : "Group203", "path" : "/Group203", "subGroups" : [ ] },  { "id" : "41962c5f-e7e9-4748-b81f-e3f1880b78de", "name" : "Sure_Groups", "path" : "/Sure_Groups", "subGroups" : []}]   Now from the above output i want to get the ID where name = Admin_UserGroup.  How can this will achieve ? How can I clone an ArrayList and also clone its items in Java?  For example I have:  ArrayList&lt;Dog&gt; dogs = getDogs(); ArrayList&lt;Dog&gt; clonedList = ....something to do with dogs....   And I would expect that objects in clonedList are not the same as in dogs list. Four complex numbers $z_1,z_2,z_3,z_4$ lie on a generalized circle if and only if they have a real cross ratio $[z_1,z_2,z_3,z_4]\in\mathbb{R}$ Let $[z_1,z_2,z_3,z_4]$ denote the  of the complex numbers $z_1,z_2,z_3,z_4\in \mathbb{C}$. Show that the distinct points $z_1,z_2,z_3,z_4\in\widehat{\mathbb{C}}$ lie on a generalized circle if and only if $[z_1,z_2,z_3,z_4]\in\mathbb{R}$.    I saw this statement claimed in , and wondered how one would go about showing it. I know of some facts we could work with:   First, the definition: A  in $\mathbb{C}$ is either a circle or a line in $\mathbb{C}$. I know that a Mobius transformation maps generalized circles to generalized circles. I know that if $f$ is a Mobius transformation and $z_j'=f(z_j)$, $j=1,2,3,4$, then $[z_1',z_2',z_3',z_4']=[z_1,z_2,z_3,z_4]$.   I have posted a potential proof as an answer below. Please let me know if you think it's complete. Thank you! "Calling dibs" - what does it imply? The term "to have dibs on something" or "to call dibs on something" plays a recurring role in American film and television (e.g. ), so it gets exported a lot.   describes "dibs" as     [...] a common, "informal" convention to reserve or declare full or partial ownership of a community resource, such as a chair [...]   From the usages in the media I have seen, this convention also seems to contain some moral concept which is not described in dictionaries. For me, it looks like by calling dibs (or ), the caller actually receives the (implicit, moral) right to that resource, and this typically goes undisputed by their rivals.  Can you confirm the existence of this concept? Is this something that varies between groups of people (or maybe between regions), or is there a concensus on how to respond to this? How do I configure Apache 2 to run Perl CGI scripts? I would like to configure Apache 2 running on Kubuntu to execute Perl CGI scripts. I've tried some steps that I came across by googling, but nothing seems to work.  What is the right way of achieving this? Why do database guys go on about normalisation?    What is it? How does it help?    Does it apply to anything outside of databases? I have observed that in gedit if I edit a file, another file is created in the same directory (the one with the same filename and a tilde '~' suffix). The extra file remains even if I close gedit.  I understand the need for a temp file (eg. in case of a crash), but vim for example deletes the extra file it creates, when I close it.  Is there a way to do the same with gedit? Some configuration perhaps? Why do some actors in credits appear as - Character (As Actor) Minimum reputation for answering your own question should be higher than what is needed to ask If we're implementing , why don't we also require that users have at least 1.5 times the amount of reputation needed to ask their current question in order to answer their current question?  I believe this would really reduce the amount of non-answers that should have been edits to the original question, or perhaps a comment under another answer.  Edit  Inspired by marcog's excellent suggestion , perhaps it would make more sense to set a minimum amount of time that must pass before you can answer your own question. New users would need to wait in the neighborhood of six hours, while users with more reputation could answer their own question within minutes if they discovered the solution on their own.  This would get in the way of the behavior that we don't want, which is people posting answers that should have been edits while not annoying most. How should a physics student study mathematics? Note: I will expand this question with more specific points when I have my own internet connection and more time (we're moving in, so I'm at a friend's house).  This question is broad, involved, and to some degree subjective.  (I started out as a physics-only student, but eventually decided to add a mathematics major. I am greatly interested in mathematics; the typical curriculum required for physics students is not deep or thorough enough; mathematics is more general (that means work!); and it only requires a few more classes. Naturally, I enjoy  immensely.)  This question asks mainly of undergraduate-level study, but feel free to discuss graduate-level study if you like.  Please do not rush your answer or try to be comprehensive. I realize the StackOverflow model rewards quick answers, but I would rather wait for a thoughtful, thorough (on a point) answer than get a fast, cluttered one. (As you probably know,  produces clear, useful writing; and a properly-done comprehensive answer would take more than a reasonable amount of time and effort.) If you think an overview is necessary, that is fine.  For a question this large, I think the best thing to do is focus on a specific area in each answer.    Update: To Sklivvz, Cedric, Noldorin and everyone else: I had to run off before I could finish, but I wanted to say I knew I would regret this; I was cranky and not thinking clearly, mainly from not eating enough during the day. I am sorry for my sharp responses and for not waiting for my reaction to pass. I apologize.  Re: Curricula:   Please note that I am not asking about choosing your own curriculum in college or university. I did not explicitly say that, but several people believed that was my meaning. I will ask more specific questions later, but the main idea is how a physics student should study mathematics (on his or her own, but also by choosing courses if available) to be a competent mathematician with a view to studying physics.  I merely mentioned adding a mathematics major to illustrate my conclusion that physics student need a deeper mathematical grounding than they typically receive.   And now I have to run off again. What does functools.wraps do? Is there a reason why people can't just take the helicopter to mount Everest? Why is it that helicopters can't reach that high? How/when to become independent in research as a graduate student? I am in the last months of my MSc and I have done my thesis. I have published some conference papers but most of them were literature reviews.  My MSc thesis is about solving wave equations by means of method of potentials and boundary elements. I am interested in pursuing research in another field (differential equations) but I have no idea how to start any topic that may lead to a journal publication.    By asking this question, I want to understand how a research student, whether a recently graduated MSc student or a PhD student, can start searching for a new research topic and develop some researches based on his own interests. Specially, I would like to know:   To what extent should a graduate student be dependent on faculty members? How can he be more independent and start his own research activities? Is it a good idea that the graduate work on another topic with the faculty member or work independently on a more recent research topic? If the person is in a research group or at the university, is it a good idea or is it ethical that he develop his own research interests, besides to the topics which are being developed in that institute? How should a graduate student manage this and make some progress in the research fields of his own interest? (In particular, sometimes the faculty members are not interested in the topics you are interested in and the person has to start his own research activity.)      And also, if this research is part of his independent research, at the time of publishing what affiliation should be used in the publications. Should it be "Independent Scholar" as mentioned in  or something else? This is important in academic publications, because sometimes, the person is in a research group, but he is publishing a paper as part of his own researches not the things he is doing in that institute; in this case, has he mention that institute's affiliation or use his own one? So please make it clear that how the affiliation would be when the person does research independently in the cases like when he is not working in a research group or he is working with a professor or research group but his publication is output of his own research activities? It is a little unclear. Aligning numbers by decimal points in table columns Integrate $\int_{0}^{\pi}{\frac{x\cos{x}}{1+\sin^{2}{x}}dx}$ Prove $0! = 1$ from first principles How can I prove  from first principles that $0!$ is equal to $1$? Prove the following inequality:   $$\dfrac{e^x + e^{-x}}2 \le e^{\frac{x^2}{2}}$$   This should be solved using Taylor series.  I tried expanding the left to the 5th degree and the right site to the 3rd degree, but it didn't help.  Any tips?