Nothing shown after logging in. Only Desktop picture (is it right? the purple one) is shown. that's all.  How can I do about this? I normally used Ubuntu 15.10. But Ubuntu 16.04 doesn't.  My system is  - Intel core-i7 6700k - Asus Z170-A - Samgsung DDR4 8GBx2 - Samgsung SSD 850 Pro 1TB - nVidia Geforce 970
When I login, nothing happens.   I am presented with my desktop wallpaper.    No Dash, no Launcher, nothing.
How to completely uninstall gnome-shell and all extensions? In Python, is there a concise way of comparing whether the contents of two text files are the same? I don't care what the differences are.  I just want to know whether the contents are different. How to find a program which is preventing sleeping? I am noticing that recently my laptop does not go to sleep/lockout after its configured X minutes of inactivity like it did in the past. I suspect some program (like media player does) is preventing it from going to sleep. I do not have any media player running, so how can I find which program is preventing it from sleeping?  It does go to sleep if I close the lid. But I would also like for it to go to sleep after X minutes of inactivity.  Update: Upgraded to Ubuntu 18.04 with default Gnome and Wayland enabled. How can I revert a config file back to the originally installed version after I have edited it? I want to revert a file in /etc/ back to its originally-installed form. I have edited the file since it was installed. How can I revert this config file? Apt is smart enough not to overwrite edited config files, so how do I tell it that I want it to do so?  For argument's sake, let's say that I want to revert the file /etc/foo.conf from the package foo. How to get this blur texture effect in photoshop? Prove that T is diagonalizable if and only if the minimal polynomial of T has no repeated roots. Efficient computation of $\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor$ I realize that there is probably not a closed form, but is there an efficient way to calculate the following expression?  $$\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor$$  I've noticed $$\sum_{k=1}^n \left\lfloor \frac{n}{k}\right\rfloor = \left\lfloor\frac{1}{2}\sum_{k=1}^{\left\lfloor\frac{n}{2}\right\rfloor} \left\lfloor\frac{n}{k}\right\rfloor\right\rfloor + \sum_{k=1,\ odd(k)}^n \left\lfloor \frac{n}{k}\right\rfloor$$  But I can't see an easy way to let the second term enter in a recursion. In a world without air, I understand they definitely would. However, with drag taken into account, I think they wouldn't. Since the drag force varies proportional to the square of speed (ignoring the change in coefficient of drag with speed), wouldn't the total impulse due to drag on a bullet fired from a gun from a specific height horizontal to ground be higher than the total impulse on an identical bullet dropped from the same height with no horizontal velocity?  Also, when bullet spin is taken into account, the bullet fired from a gun should resist change in orientation; therefore, it should maintain a small but non-zero angle of attack, and also have a lift force, correct? Find the product $\prod_{n=1}^{\infty} (1+x^{2n-1}) $ Who is responsible for defining a site logo? I mean, there are moderators of the site that define it, or stackexchange defines it? t-test for partially paired and partially unpaired data I am using eclipse and i get this error--I think it's an error with the way i imported becker.robots Partitions of $n$ into distinct odd and even parts proof Let $p_\text{odd}(n)$ denote the number of partitions of $n$ into an odd number of parts, and let $p_\text{even}(n)$ denote the number of partitions of $n$ into an even number of parts.  How do I prove that    $|p_\text{even}(n) - p_\text{odd}(n)|$ is equal to the partitions of $n$ into distinct odd parts. Show that the number of partitions of $n$ for which no part appears exactly once is equal to the number of partitions of n for which every part is divisible by 2 or 3. Show that the number of partitions of $n$ for which no part appears more than twice is equal to the number of partitions of $n$ for which no part is divisible by 3. Is any quotient of a Euclidean domain by a prime ideal a Euclidean domain? Let $R$ be a Euclidean domain, i.e., a ring with a norm $N : R \rightarrow \mathbb N$ such that for any $a,b\in R$ with $b\not=0$, we may write $a = qb + r$ for some $q,r \in R$ with $N(r) &lt; N(b)$. Let $I$ be a prime ideal of $R$, so $R/I$ is a domain. Must $R/I$ in fact be a Euclidean domain?   I know that this is true if we replace "Euclidean domain" with "PID", and false if we replace it with "UFD", so there is no clear intuition to be gained from similar concepts. My first attempts at a proof was to borrow a construction from analysis and define a norm on $R/I$ by  $N(a + I) = \inf\{N(a+i) : i\in I\}$  but this didn't really get me anywhere.   So, this fact true? If so, how can I prove it? If not, whats a counterexample? How do the Treasure Goblins work? Every once in a while I'll come across the sneaky devils and they always flee.  What determines when they flee (time, distance, etc.) and do I get better loot by killing them faster?  Is there anything else I should know in order to get the most out of the encounter?  EDIT: What I mean is: Is the final drop better based on how effectively I defeat them? I know that the usual ordering of $\mathbb R$ is not a well-ordering but is there an uncountable $S\subset \mathbb R$ such that S is well-ordered by $&lt;_\mathbb R$?   Intuitively I'd say there is no such set but intuitively I'd also say there is no well-ordered uncountable set at all, which is obviously wrong. I still struggle to grasp the idea of an uncountable, well-ordered set. JAXB Java generating XML, Why lowercase? Octal number literals: When? Why? Ever? I have never used octal numbers in my code nor come across any code that used it (hexadecimal and bit twiddling notwithstanding).  I started programming in C/C++ about 1994 so maybe I'm too young for this? Does older code use octal? C includes support for these by prepending a 0, but where is the code that uses these base 8 number literals? Reset or remove the BIOS password on my laptop Recently, Firefox has changed the default folder for newly created bookmarks (using Ctrl+D) from the Bookmarks Menu to "Other Bookmarks".  Is there some way to change that back? Or some alternate method instead of Ctrl+D?  EDIT  A native way to do this (without an add-on) would be best.