I installed OpenStack and then I shutdown the laptop. After turning on the laptop again I can't enter the programmer.  How can I save my work in Ubuntu?
Is there a way to save all my typed terminal commands and view it like history in a log book?
How to make `cd dir/filename` take me to dir/? I would find it very convenient to be able to use cd with a file argument.  cd myDirectory/anyname.anyExtension would be equivalent to cd myDirectory/  What would be the best alias or function to achieve this behavior ?  EDIT: Sorry I didn't mention it in the 1st place: I use zsh Can Cycles use multiple UV layers? Why is the network configuration I set in /etc/network/interfaces ignored on Ubuntu 17.10? If $X$ is measurable space, $f : X\to [-\infty,+\infty]$, function such that $f^{-1}([-\infty,r))$ measurable for all rational numbers $r$,prove than $f$ is measurable  I know that $f$ is measurable iff set $\{x\in X : f(x)&lt;a\}$ is measurable for all $a\in \mathbb{R}$ but for $a\in\mathbb{Q}$ I don't know how to proceed. Check for missing fonts/characters in XeLaTeX? How do you factorise $x^3z - x^3y - y^3z + yz^3 + xy^3 - xz^3$? I'm trying to factorise $$ x^3z - x^3y - y^3z + yz^3 + xy^3 - xz^3 $$ into four linear factors.  By plugging it into WolframAlpha I've learned that it's $$-(x-y)(x-z)(y-z)(x+y+z)$$  My question is: what are the steps involved in factorising the expression? Is there a method I don't know about that I'd have access to with my limited maths?  Really appreciate any help! Fantasy piece involving different worlds and a crippled protagonist This is a novel that I think I remember reading somewhere in the 1990s courtesy of my brother (who does not remember the book). Only a few details are coming to mind at the moment. It's a male protagonist. Something was not quite right with his legs, which led to him being nicknamed Frog or Leapfrog due to his usual method of locomotion, which consisted of pushing off from his legs to his hands and vice versa. Something happens and he winds up moving between a number of worlds (I want to say that he fell into a well or a hole in a field). There was a part which stuck with me where he's in a bottomless hole and finds he keeps falling faster and faster without end with the rushing wind becoming actively painful (I don't remember if he actually reaches a terminal velocity or if some aspect of the world prevented it while still allowing the rushing air to affect him physically).  Unfortunately, that's all I can remember. I don't remember whether he eventually gains companions on the voyage or how it ended. The most vivid memory is that of the nonstop falling. How to add a guest account without a password? Default Class Accessibility in C# by default is a class:   private ? internal ?  sealed ? I'm looking for a short story whose title I can't remember.  In it a wealthy man practices cloning and consciousness transfer to achieve immortality, often parading older bodies around his estate naked (not a nice guy). The story follows a final transplant, which doesn't go as expected. The man is left trapped with his memories and no ability to speak, while the clone walks off behaving exactly as he would. Greatest common divisor of two positive integers Viruses: Adaptation to a new host through repeated host jumps Extracting one band from three band raster in ArcMap? `test` and `[` - different binaries, any difference? I noticed while answering another question that test and [ are different binaries, but the [ manpage pulls up test's. Besides the requirement for an ending ], is there any difference?  If not, why are they separate binaries instead of being symlinked? (They are also bash builtins, and bash doesn't show a difference either.) How to rename objects with python? I want to rename the number 1->picture (32) with python not the number 2->picture with the (3745), can someone help me with that ? I'm hoping someone can help me as this is driving me nuts! Context and Chronological info I'm trying to find the title/author of a short story that I read in some or other anthology ages ago. I couldn't give you an exact date but I'd say it was probably 50s/60s. Plot The human population has increased to the point where input and output of resources on Earth is in exact equilibrium. As such, no other living matter can be permitted to exist, as its use of resources would throw this equilibrium out of balance. One man in a vast tower block has managed to hide some flowers, and, I think, one or a few small animals - perhaps a mouse. These are detected by the relevant authorities, and the story ends when an official arrives at the apartment and requires the man to destroy them - the last non-human living things on Earth. It just struck me that Utility Companies world-wide supply domestic users at either 50/60Hz. It could have been selected to be 10 Hz, or 100 Hz ... whatever  Was 50/60 chosen at random? Is there some rationale involved (efficiency, easier to construct/control etc) in restricting domestic supply to either 50/60 Hz?  In other words, if I were designing a power system, why would I pick 50/60 Hz instead of some other frequency? Mysql resolving 127.0.0.1 to hostname How can I clear the water out of this area? I've sectioned of this area in the sea near my base, and I need to get rid of all the water from it.  From what I've tried the only way I can see to clear it is fully cover one layer, delete the blocks, then go down to the next layer. Is that the only way I can clear the area or is there a better approach?  Ideally I'd like a survival method (if there is a better one), but any commands what could be used I'd like to hear just so I can learn more commands :) Equivalent Definitions of the Operator Norm How do you prove that these four definitions of the operator norm are equivalent? $$\begin{align*} \lVert A\rVert_{\mathrm{op}} &amp;= \inf\{ c\;\colon\; \lVert Av\rVert\leq c\lVert v\rVert \text{ for all }v\in V\}\\ &amp;=\sup\{ \lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert\leq 1\}\\ &amp;=\sup\{\lVert Av\rVert\;\colon\; v\in V\text{ with }\lVert v\rVert = 1 \}\\ &amp;=\sup\left\{ \frac{\lVert Av\rVert}{\lVert v\rVert}\;\colon\; v\in V\text{ with }v\neq 0\right\}. \end{align*}$$