I made another big screw-up, but I might be able to fix it. Whenever I use sudo [command], I always get  -bash: /usr/bin/sudo: cannot execute binary file: Exec format error   I recently did chmod -R 777 /,but stopped it immediately, however, I get the error above. Does anybody know how this can be fixed?  Thank you in advance
I accidently ran  sudo chmod 755 -R /   instead of  sudo chmod 755 -R ./   I stopped it after few seconds, but now there is some problems such as  sudo: must be setuid root   How can I revert permissions back?
It looks like this issue has , but it just happened again on Travel.SE. Perhaps this is another corner case? These two questions are closed as duplicates of each other.           I had the last vote on each, although in both cases, my vote was for "Unclear what you're asking", but the weight of votes in both cases were for the duplicate status. So if the existing checks are only in place at the time someone casts a close vote, that would explain how this one got in under the radar. Perhaps another check needs to be done when the question is actually closed, not just when close votes are cast?  And as @gnat points out, low-rep/logged-out users get a Redirect loop when trying to load either question.  NOTE: A moderator has already fixed this particular circular duplicate situation by closing one of the questions with a different close reason. Does Auto White-Balance Really Work? How? Calling Table with custom iterator Hibernate has a handful of methods that, one way or another, takes your object and puts it into the database. What are the differences between them, when to use which, and why isn't there just one intelligent method that knows when to use what?  The methods that I have identified thus far are:   save() update() saveOrUpdate() saveOrUpdateCopy() merge() persist() Is it possible to load a raster file (e.g. geotiff or erdas img) directly into a Leaflet map? If so, can you guide me to the correct documentation or method to do this? I am trying to do this with the imageOverlay() function in Leaflet currently.   var imageUrl = 'http://localhost/test/my_raster.tif',         imageBounds = [[30.430224, -87.193133], [30.435867, -87.185944]];         L.imageOverlay(imageUrl, imageBounds).addTo(map);    I am new to Leaflet. requireJS optional dependency Does time stretch all the way back for infinity or was there a point when time appears to start in the universe?  I remember reading long ago somewhere that according to one theory time began shortly before the creation of the universe.  Does time have a starting point of note? Why does the logo not show up when signing up for a site and confirming the account? How to Recover truncate table in MySQL? Let $\Bbb R^+$ be the set of positive real numbers. Use Zorn's Lemma to show that $\Bbb R^+$ is the union of two disjoint, non-empty subsets, each closed under addition. Aiming at specific body parts How to convert strings into integers in Python? I have a tuple of tuples from a MySQL query like this:  T1 = (('13', '17', '18', '21', '32'),       ('07', '11', '13', '14', '28'),       ('01', '05', '06', '08', '15', '16'))   I'd like to convert all the string elements into integers and put them back into a list of lists:  T2 = [[13, 17, 18, 21, 32], [7, 11, 13, 14, 28], [1, 5, 6, 8, 15, 16]]   I tried to achieve it with eval but didn't get any decent result yet. I have a profile on AskUbuntu.com which is recognized on my StackEchange profile (). I have already asked and answered questions there. But even though I'm logged in stack exchange, Askubuntu does not see me as logged in. I have a long history of problems with that and though I have been able to access it up to end 2018, and I don't understand why it can't do it anymore. I have seen multiple questions about similar problems, but they all are older than 2018 and do not really helped me solve it. Amongst other, they proposed to log in with the same user and password, but using the same user and password on two different log in systems is a security hole. either your credential cookies are shared, or one should use different logging info. EDIT: it has been suggested to deactivate third party cookies blocking, but I do not want to ruin my browser's tracking protection. How to prove for each positive integer $n$, the sum of the first $n$ odd positive integers is $n^2$? I'm new to induction so please bear with me. How can I prove using induction that, for each positive integer $n$, the sum of the first $n$ odd positive integers is $n^2$?  I think $9$ can be an example since the sum of the first $9$ positive odd numbers is $1,3,5,7,9,11,13,15,17 = 81 = 9^2$, but where do I go from here. In the first book, Harry sees his Gringotts vault for the first time.  (Quotes thanks to Slytherincess!)     Griphook unlocked the door. A lot of green smoke came billowing out, and as it cleared, Harry gasped. Inside were mounds of gold coins. Columns of silver. Heaps of little bronze Knuts.      "All yours," smiled Hagrid.      All Harry's -- it was incredible. The Dursleys couldn't have known about this or they'd have had it from him faster than blinking. How often had they complained how much Harry cost them to keep? And all the time there had been a small fortune belonging to him, buried deep under London.      Hagrid helped Harry pile some of it into a bag. "The gold ones are Galleons," he explained. "Seventeen silver Sickles to a Galleon and twenty-nine Knuts to a Sickle, it's easy enough. Right, that should be enough fer a couple o' terms, we'll keep the rest safe for yeh."      Harry Potter and the Sorcerer's Stone - pages 58-59 - US Hardcover Edition   Jk Rowling posts in the Harry Potter Lexicon      JKR has stated in an interview (Comic Relief 2001) that she estimates the value of one Galleon to be "about five pounds," which works out to around US$9.75 (the exchange rate at the time of the interview was US$7.33). In the introduction to both QA and FB, US$250-million is stated to be the equivelent of 34 million Galleons. That also works out to a value of £5 to the Galleon, at the exchange rate of the time. The price listed on the back of the books, however, is not correct, since US$3.99 would equal less than half a British pound, or 8 sickles and 15 knuts. The book instead incorrectly lists US$3.99 as being equal to 14 sickles and 3 knuts. (Unfortunately, CNN.com uses this incorrect value for their Knuts-to-dollars converter.)      This gives us approximate values as follows:      1 bronze Knut = £0.01 (US about 2 cents)      1 silver Sickle = £0.29 (about US$0.57)      1 Galleon = £5.00 (more or less US$9.75)      These rates vary as the exchange rate fluctuates - see the Wizarding World Currency Converter for the current rate.   Now looking at the quote      Hagrid helped Harry pile some of it into a bag.   and     Right, that should be enough fer a couple o' terms, we'll keep the rest safe for yeh.   Obviously "some" is unspecified, but presuming the costs of ...     Typical elementary-school textbooks cost more than $100 each   He would be carrying at least 10 galleons for each school book, and going by the list of books just for his first year,  (Thanks Ibid!)     COURSE BOOKS      All students should have a copy of each of the following:         The Standard Book of Spells (Grade 1) by Miranda Goshawk   A History of Magic by Bathilda Bagshot   Magical Theory by Adalbert Waffling   A Beginners’ Guide to Transfiguration by Emeric Switch   One Thousand Magical Herbs and Fungi by Phyllida Spore   Magical Drafts and Potions by Arsenius Jigger   Fantastic Beasts and Where to Find Them by Newt Scamander   The Dark Forces: A Guide to Self-Protection by Quentin Trimble         (Harry Potter and Philospher's Stone, Chapter 5)   That's 80 Galleons just for books. This does not include the list of other expenses Harry has for his school years (wand, potion reagents, etc.)  How many Galleons is "some" or is Diagon Alley selling supplies for third world prices?  Sidenote, is this just a case of bad JK maths? Run command whenever someone joins a Minecraft server Is there any way to run a command automatically when a player joins the server? I need to do this without the use of a Bukkit plugin. I think it's possible with MCP but I want to know how! Kaplansky's theorem of infinitely many right inverses in monoids? There's a theorem of Kaplansky that states that if an element $u$ of a ring has more than one right inverse, then it in fact has infinitely many. I could prove this by assuming $v$ is a right inverse, and then showing that the elements $v+(1-vu)u^n$ are right inverses for all $n$ and distinct.  To see they're distinct, I suppose $v+(1-vu)u^n=v+(1-vu)u^m$ for distinct $n$ and $m$. I suppose $n&gt;m$. Since $u$ is cancellable on the right, this implies $(1-vu)u^{n-m}=1-vu$. Then $(1-vu)u^{n-m-1}u+vu=((1-vu)u^{n-m-1}+v)u=1$, so $u$ has a left inverse, but then $u$ would be a unit, and hence have only one right inverse.  Does the same theorem hold in monoids, or is there some counterexample? Is CAT5 cable good enough for RS-485 vs "true" RS-485 cable How To Make A Solid Object Drop To The Ground Like It Was Liquid So I have a simple bouncing ball animation, but I just wanted to something "weird" for the ending. Is there a way to change the ball's material on the fly, where after the last bounce it changes materials and physical composition from a rigid body(baked animation now) to a fluid sim?  (within 30-40 frames) What would happen if the earth would stop spinning? How much heavier would we be? I mean absolutely stop spinning. How much does the centrifugal force affect us?  If you give technical answers (please do), please explain them in laymen's terms, thanks.  Edit: I am asking what would be different if the earth were not spinning. Nevermind the part about it stopping.