$ cd / /$ ls bin   dev  home        initrd.img.old  lib64       media  opt   root  sbin  sys  usr  vmlinuz boot  etc  initrd.img  lib             lost+found  mnt    proc  run   srv   tmp  var  vmlinuz.old  /$ cd // //$ ls bin   dev  home        initrd.img.old  lib64       media  opt   root  sbin  sys  usr  vmlinuz boot  etc  initrd.img  lib             lost+found  mnt    proc  run   srv   tmp  var  vmlinuz.old //$ pwd //  //$ cd /// /$ /$ pwd /   What is this trickery? What is //?
In unix/linux, any number of consecutive forwardslashes in a path is generally equivalent to a single forwardslash. eg.  $ cd /home/shum $ pwd /home/shum $ cd /home//shum $ pwd /home/shum $ cd /home///shum $ pwd /home/shum   Yet for some reason two forwardslashes at the beginning of an absolute path is treated specially. eg.  $ cd ////home $ pwd /home $ cd /// $ pwd / $ cd // $ pwd // $ cd home//shum $ pwd //home/shum   Any other number of consecutive forwardslashes anywhere else in a patch gets truncated, but two at the beginning will remain, even if you then navigate around the filesystem relative to it.  Why is this? Is there any difference between /... and //... ?
How to be granted root rights while browsing files/directories with Nautilus I'd like to know if there a way to be granted root rights while using Nautilus 2.30 ?   For example I'd like to move some old folders of long unused users from the home directory - remains of previous distros (Debian).   Of course I can open a terminal, but I want to know if it is possible to do that with a mouse in Nautilus. "elements required by agent" is "required" here an adjective or verb? "elements required by agent" is "required" here an adjective or verb?  another example "elements expressed by person". I have both Windows 7 and Ubuntu installed on a shared machine. Because a lot of the non-developers use Windows, I'd like to change the boot order to make it easier for them.  Currently the boot order looks like the following:   Ubuntu 11.10 kernelgeneric *86 Ubuntu 11.10 kernelgeneric *86 (safe boot)  Memory test Memory test Windows 7 on /dev/sda6   How do I change the default order so that Windows 7 is at the top of the list?   Windows 7 on /dev/sda6 Ubuntu 11.10 kernelgeneric *86 Ubuntu 11.10 kernelgeneric *86 (safe boot)  Memory test Memory test Trying to identify a very old short story about aliens colonizing human bodies Don't remember the exact start to the story, but it went something like "walking along a path" or something, and when he hears what sounds like a shotgun blast behind him, he then feels something strike him in the butt. He passes out, and when he awakens, he discovers that the "shotgun blast" was actually a miniature spaceship that exploded and shot miniature aliens into his body. The aliens prove to be very beneficial because they clean up all the toxins and other poisons in his body. They can be transmitted through kissing or sexual activity.  Any help with the name of the story would be greatly appreciated.  Dan Find the solution of following differential equation:     $$\frac{dy}{dx}=\frac{1}{xy(x^2 \sin (y^2)+1)}$$   Could someone hint me something to get through this problem? A commercial airport being any airport that has regular scheduled passenger flights.  The mathematics of  got me thinking: is the network of scheduled flights a connected graph?  That is, is there a pair (or triplet or even larger set) of airports such that they only have scheduled flights with each other?  Or can you get from any airport to any other?  Ignore vagaries like cargo and general aviation. I'm looking for two airports that I can shuttle between, but would have to drive (or sail) to get to one or the other of them. I had the following two problems:     Find a counterexample for $f_*(A \cap B) \supseteq f_*(A) \cap f_*(B)$ and $ f_*(A-B) \subseteq f_*(A) -f_*(B).$ Where $f_*(X)$ is the image of $X$ under $f$ for some function $f:A \rightarrow B $ and some subset $X \subseteq A$.   I came with the following answer:  Let $ f: \mathbb{Z} \rightarrow \mathbb{Z} $, where $f: x\mapsto 0$; let $A=\{1,2\}$, and $B=\{3,4\}$.     For $f_*(A \cap B) \supseteq f_*(A) \cap f_*(B)$, $$ f_*(A \cap B) = f_*\{ \varnothing\} = \varnothing \hspace{1cm} \text{and} \hspace{1cm} f_*(A) \cap f_*(B)=\{0\} \cap \{0\} = \{0\}. $$ It follows that $ \varnothing \nsupseteq \{0\} $. For $ f_*(A-B) \subseteq f_*(A) -f_*(B)$, $$f_*(A-B)=f_*(\{1,2\})=\{0\} \hspace{1cm} \text{and} \hspace{1cm} f_*(A) - f_*(B) = \{0\} - \{0\} = \varnothing$$ It follows that $ \{0\}  \nsubseteq \varnothing $.   Now (assuming my answer is correct), let's say I want to find more counterexamples or maybe a more general answer (e.g. all the conditions under which the inclusion fails). Other than by trial and error or just intuition, how would I do that?   I know this is a broad question, so I'm specifically asking for methods or advice on how to build counterexamples in elementary set theory (for example, tips on where to begin or rules that apply in general that may be unobvious). Warning  If you're looking for advice how to make your document look like it's been written in Word, this is most likely not the question you're looking for. This question is mostly of theoretical nature, as it results in tiny differences, which will most likely not be noticed by someone who doesn't allow the use of LaTeX.  Questions that might be more helpful for this matter are:           Question  I learned that MS Word uses a slightly different version of the unit "point" (pt) than TeX does:     The 12 point of Word will be PostScript point, which in TeX would be called 12bp. A TeX pt is slightly smaller: it's 1/72.27 inch, while a bp/PostScript point is 1/72 inch. See also    ( in )  I'm writing a paper that would usually be expected to be "typeset" in MS Word, thus I want to use the same font size as Word would.  How do I set a document e.g. in the "12pt" font size that MS Word would use?  In case it matters, I'm using the article document class, Latin Modern (lmodern) as a font with the T1 font encoding and compile with pdfLaTeX, but input on different set-ups is more than welcome. How to give an image or video a TV screen effect? I thought it would be interesting to create a .blend that filters any regular video or image with vintage television look.   Edit: Although this question initially arose from my desire to create a vintage look, it has since been pointed out in a comment that all displays use arrays of RGB emitters, so it's not really an issue of vintage or not. How vintage it will end up looking is probably more a matter of the shape, size, and density of the emitters.  Reference images:       Upon examining the structure of screens, the most common seems to be rows of vertical RGB bars:    Here is another type which I believe is common in computer displays - circular dots in a hexagonal grid:    I have been thinking about how to make a screen in Blender that takes its input from an image or image sequence and for each frame converts the RGB value for a pixel (or region) and uses that to illuminate the red green and blue phosphors in the correct ratios so that when viewed from a distance an image is distinguishable.  Do you think this will require python scripting? I made some initial attempts modeling an array of phosphors then using a Light Path node and a Separate RGB node in Cycles but I haven't gotten very far. I would love to hear what you all can suggest.  Thanks! Continuous function on R which tends to infinity on open interval must have a minimum Suppose we have $f : \mathbb{R} \to \mathbb{R}$ continuous and $$\lim\limits_{x \to \pm \infty} f(x) = \infty.$$  Then must $f$ have a minimum on $\mathbb{R}$?  Intuitively it seems so, and it's easy to prove for some arbitrary closed interval in $\mathbb{R}$ with the Extreme Value Theorem, but how can we apply that to an open interval like $(-\infty, \infty)$? Creating a row for each value in a comma-separated string I'm currently trying to create a View from a Table that does the following:  Table A ╔═════════════╦═══════════════╗  ║ PART NUMBER ║   FILE NAME   ║ ╠═════════════╬═══════════════╣ ║  PN0001-01  ║      FOO      ║ ║  PN0002-01  ║      BAR      ║ ║  PN0003-01  ║    FOO,BAR    ║ ║  PN0004-01  ║  BAR,FOO,FOB  ║ ╚═════════════╩═══════════════╝   To create  View B ╔═════════════╦═══════════════╗  ║ PART NUMBER ║   FILE NAME   ║ ╠═════════════╬═══════════════╣ ║  PN0001-01  ║      FOO      ║ ║  PN0002-01  ║      BAR      ║ ║  PN0003-01  ║      FOO      ║ ║  PN0003-01  ║      BAR      ║ ║  PN0004-01  ║      BAR      ║ ║  PN0004-01  ║      FOO      ║ ║  PN0004-01  ║      FOB      ║ ╚═════════════╩═══════════════╝   So, essentially, I need to take records from Table A and insert them into View B, where if the record from A has a LIKE '[,]' property, then that field is split into multiple records in B, depending on the number of times the ',' is present, with the text between each ',' being given its own record in View B. To show that $2$ | $x^{2n} - x^n$, $n \in \mathbb{Z^+}$ is the following adequate? Can I use a Thunderbolt display for a macbook pro with a mini display port? How to show $\omega^n$ is a volume form in a symplectic manifold $(M, \omega)$? postfix doesn't work after iptables set up How to print variables without spaces between values Trouble Viewing Whole HDR Image as cycles world When I load an HDR image into an environment texture using Cycles Render, only a small fraction of the image appears. I have a feeling it's an easy fix, but I can not find what needs to be changed. I have been reading the top posts here, and the recommendations for what to invest in are often similar. What I'd like to know, in as simply of terms as possible, is what the consensus is on priority of these investments.  I am new to this, but here are some of the obvious options:   Paying off credit card debt Paying off mortgage / student loans 401k up to employer match 401k past employer match IRA Emergency fund Other important investments that I have missed   Clearly this will vary person to person, but if you were asked to put an ordered recommendation on a highway billboard, what would it be?  (For example:   Pay off credit debt Emergency fund for 6 months 401k up to match ... ) Is there a way to make a fullscreen on VirtualBox? I tried many ways to make a bigger screen in VirtualBox because I do not like the small size of the guest window? Is there is a way to make it big? Can i install ubuntu on meizu mx4 android edition like ubuntu edition with iso recovery in this page "  "