I am using Ubuntu 16.04.1 LTS through the Oracle VM Virtualbox. At the beginning of my installation, I was asked to set a password for my login, which works perfectly every time I log in to my virtual box.  However, when I tried today to change my password with passwd, I get the following error messages:  passwd: Authentication token manipulation error passwd: password unchanged   Therefore, I cannot change my password. The point is that I am pretty sure I am typing correctly my password since it is also my log-in password (it consists of characters [some in upper case], numbers, and an asterisk *).  Is there anything I could do to find out what's happening or a way to change my password?  PS: Everything began from my attempt to use sudo -, where again my typed password gets rejected.
I am logging in to my Ubuntu Server using my username. Once I am logged in I am typing passwd command. Entering a new password but a second after getting following error messages:  passwd: Authentication token manipulation error passwd: password unchanged   What is wrong here? How can I change my password otherwise if I don't have access to that server physically, i.e. I am connecting remotely with ssh using terminal.
The differences between TeX engines I am confused about what TeX and its offspring (LaTeX, pdfTeX/pdfLaTeX, e-TeX, ConTeXt, LuaTeX, etc.) are.  Some, like LaTeX, seem like add ons to TeX (maybe a change to the eyes and mouth, but not stomach). Others, like pdfTeX, seem like changes to the underlying system (i.e., a change to the stomach).  Is there a good reference that explains the differences and the evolution? Activate physics by keyframe I'd like to have a group of debris fall from a ceiling onto the floor, but not have them drop all at the same time. Is there a way to set a keyframe that dictates when the object enters the simulation? For example, object 1 starts falling on frame 0, object 2 on frame 5, object 3 on frame 24, etc. Given $E[Y]=1$ , $E[Y^2]=2$ and $E[Y^3]=5$, Y non negative integer random variable, find min of $P[Y=0]$ Would someone give a thorough explanation of 1.14 Minecraft's /data modify? Okay, so I've been searching all over the internet for an explanation of data modify ever since I heard Sethbling passively mention it in one of his videos. The only  thing I could find on it was the wiki and the update log for the 1.14 snapshot. So, I checked these, and they hardly explained it at all. I can get /data modify block 123 20 123... and that's as far as I get.  Minecraft wiki does not at all define clearly what  is (the thing meant to go after coords), nor does it specify what each operation does to what. Operations include (without explanation, and excluding set (which it does explain)): append, insert, merge, and prepend. Then, it has from|value as the next option, which aren't explained either. After this, it just has block/entity and coords/id. So, I know the format (mostly), but I haven't the slightest idea what any of it means. And nothing I've seen on the internet even mentions the command save for Minecraft wiki itself.  Please explain if you know what data modify is. Thanks! 90s (or earlier) Japanese anime movie: two planets at war, young man is in love with princess from the other planet, and floods his own village I would like to find out the title of a Japanese anime feature film (not a series) that I saw on Romanian TV in the early 90s.   It was about a feud between the peoples of two planets (one very technologically advanced, the other not). The two planets go to war against each other, and a young man from one of the planets falls in love with a princess from the other planet.  I recall a scene where the army of the second planet take off in hot air balloons when they go to war.  The only other thing I recall is that there is a dam next to the village where the young man lives, and for some reason he opens the dam gates and floods his own village.   I do not recall there being robots in the movie, however I remember very vaguely that the technology level was probably at the level of late 19th century Europe on one planet and pre-industrial on the other one.  What it's not:   Nobunaga the Fool Aldnoah Zero Queen Millennia Uchuu Senkan Yamato (movie) What is the promotion rate of professors in United States? I'm writing an essay, and want to know the promotion rate and average duration from assistant professor to associate professor and associate professor to professor in recent years. Sadly I don't know the data for the US. Could anyone tell me? Is it possible to find all classes or interfaces in a given package? (Quickly looking at e.g. , it would seem like no.) Windows 7 task bar at autohide, make it totally disapear? My desktop look is empty so all I have is a nice wallpaper. My Windows taskbar has the "Taskbar Appearance" setting to "Auto-hide the taskbar". Although hidden, it leaves a thin top layer so you can still see it a bit, and where the pinned shortcuts are. Is it possible to totally have it hidden without a trace? This is a serious question. It really bugs m. In Fantastic Beasts: The Crimes of Grindelwald Dumbledore teaches DADA. But from the books we always heard about him as of a Transfiguration teacher (say, in Tom Riddle's days). It is stated in the movie that Dumbledore was prohibited to teach DADA by the Ministry, though the limitations seemed to be canceled at the end of the movie together with the removal of his handcuffs (not completely clear about the teaching though). The strange thing is, however, that Dumbledore was a Transfiguration teacher and even the Head of Transfiguration Department in Hogwarts before Newt's days, as we learn from Pottermore:  Under the guidance of her [McGonagall] inspirational Transfiguration teacher, Albus Dumbledore, she had managed to become an Animagus She [McGonagall] sent an owl to Hogwarts, asking whether she might be considered for a teaching post. The owl returned within hours, offering her a job in the Transfiguration department, under Head of Department, Albus Dumbledore.  That is of course if we accept that Minerva McGonagall in the movie is the same Minerva we know. So it seems that he taught Transfiguration, then for some reason switched to DADA and then to Transfiguration again. While it is possible in general, is there any explanation for the reasons? Correctly typesetting a tilde How do I set the tilde (~) character correctly in LaTeX?  There’s a  on Stack Overflow, with a lot of answers. But dare I say it? They all suck:   \textasciitilde is too high, \texttildelow is too low. $\sim$ can be tweaked to look more or less acceptable: {\raise.17ex\hbox{$\scriptstyle\sim$}} – but even that is a hack and uses the wrong symbol.   The point is – the tilde character is definitely an existing glyph in any font I am tempted to use. How can I just access and typeset that character, please? Without resorting to some other, similar-looking glyph that first needs to be nudged into place using a cunning combination of font size and raised boxes?  There must be a possibility to access that glyph directly from the font definition.  To demonstrate, look at this screenshot which attempts simply to display a C++ destructor of a type T (~T):    Compare this with the symbol we get in the browser: ~ – that’s what I want. Complex towers: $i^{i^{i^{...}}}$ For an existing set of line features, I would like to generate a perpendicular line, of say 1km, at the midpoint of each existing line feature in ArcGIS.  I imagine that The methodology would be to:   create a tangent line at the midpoint of each existing line feature calculate the angle of the tangent line based on the angle of the tangent line, calculate the location of the endpoint of the new line create the new line with the calculated endpoint of the new line and the existing midpoint of the old line   Let's assume that we are in a UTM projection and can use coordinates to calculate distance and direction.  How would I do this with ArcGIS tools or with ArcPy? I want to do something like the following in TeX:  \begin{nobreak}    Text here will not split over pages, it will remain as one continuous chunk. If there isn't enough room for it on the current page a pagebreak will happen before it and the whole chunk will start on the next page.    \end{nobreak}   Is this possible? Possible Duplicate:                If in a multiple linear regression (enter method) the general model isn't significant (F>.05) but one of the predictors is significant (β&lt;.05), should I consider it as a significant result? I read on the :     Focal-length determines the angle-of-view seen through a lens for a   given sensor-size. With a full-frame sensor a lens gives the same   angle-of-view as it would on a 35mm film camera. With a smaller   sensor, the angle-of-view becomes smaller. The crop-factor, also   called FLM, is the ratio representing the difference in equivalent   focal-lengths. So a 150mm on a full-frame DSLR such as the Nikon D700   gives the same angle-of-view as a 100mm on a D7000 since its FLM is   1.5X.      Short focal-lengths show a greater angle-of-view compared to longer   ones. [...]   In layman's terms, what is angle-of-view? Is it the same as focal length? If not, how is it different? How is it used? Why do I need to know about it? I want to have an index entry typeset as $a_\text{T}$, so I issue the command \index{at@$a_\text{T}$}. Each use of this index command creates a separate line in the index. How can I get \makeindex to recognize they all reference the same topic?  My index entries look like this: Is this correct for Rudin exercise 3.7? Prove the series is convergent This is Baby Rudin exercise 7 of Chapter 3. Prove that the convergence of $\sum{a_n}$ implies the convergence of $\sum{\sqrt {a_k} \over k}$ if $a_n \ge 0$.  Proof:  I will attempt to show that the cauchy criterion is met so $${\sum_{k=n}^m {\sqrt {a_k} \over k}} \le \epsilon $$ for all $n,m \le N_1$. Im disregarding the absolute value since its all positive terms.   Since $\sum{a_n}$ converges, we know that the $\lim \limits_{n \to \infty} a_n =0$ So there exists some $N_2$ such that for all $n \ge N_2$, $$   a_n \lt \ {{(m-n)}^2k^2(\epsilon)^2} $$ I am again disregarding the absolute values because its always positive Let N=max{$N_1,N_2$} then for all $n,m \ge N$ $$\sum_{k=n}^m {\sqrt {a_k} \over k} \le \sum_{k=n}^m {\sqrt {{(m-n)}^2k^2(\epsilon)^2} \over k} \le \sum_{k=n}^m{(m-n)(\epsilon)} = \epsilon $$  Maybe this is just crazy, should I just use Cauchy-Schwarz inequality and forget about this or could I possibly make this method work? When does a target know it's under the effects of a charm/enchantment spell? How does Azkaban's management work? How can author deal with late reviews? Another problem I personally struggle with in peer-review publication process is the situation when review takes really, really, really long. The precise definition of "long" is probably very area-specific: for example a paper in Maths will probably took longer to review than one in Physics. Many well-established journals and major publishers, sadly, prefer not to specify the "rules of the game" precisely, particularly how long the review process should normally take. Fortunately, I quite often serve as a referee with the very same journals and know the amount of time I am given to write a review. Unfortunately, when I am an author, I do not observe these deadlines to be always met. For example, a notable U.S. publisher would ask a reviewer to send a review in 2 months; but in practice a first review of my paper once took as long as 8 months.  As a rule of thumb, I usually start writing to editors with questions about "the status of my paper" in X+1 months time, when X is a deadline time for a reviewer to submit a review. This strategy is not particularly successful &mdash; what I usually get is a recommendation to be more patient. Since there is no "official" deadline time announced, there is no formal ground for complaints here.  Of course, such delays lead to a whole bunch of funny situations, particularly if a preprint is put online (e.g., on arXiv) and the results are presented in some conferences. Follow-ups with no official paper to cite, grant applications in which you can not justify by a solid publication, good research but bad bibliometrics or CV, to name just a few.   Could you recommend an efficient way to deal with this problem?