How does electricity travel near the speed of light if electrons drift at a snail pace?
Why the electric bulb turns on almost instantly when the switch is closed?
Is there a word for two persons dodging each other on the street? Jump between open windows on multiple monitors in Task View on Windows 10 with keyboard I'm using two monitors with Windows 10 and I have a few windows open on each monitor. When I open the Task View (Win + Tab) I can only navigate between the main monitor's windows with keyboard (using arrow keys or the Tab key). I see the other display's windows on that display but can't figure out how to cycle through those windows with my keyboard.  Is there a way I can give focus to secondary monitor's windows in the Task View using keyboard?  To put it another way, how do I select the first item on the right monitor in the following screenshot using keyboard? i was stopped by my sister from upgrading Ubuntu, for the reason she explained was that i would have to reinstall all the softwares that I've installed in last 6 months. but i think if that's the case, the upgrade itself includes all softwares that i have installed. so please tell me what's the truth?     please note that i just can't afford mentally to reinstall all apps due to slow INTERNET speed.because it may take 3 to 4 days of constant downloading.   if you are an Indian living in an suburban city,you can understand my situation.   i think the question itself explains everything.still I'll explain everything in detail.i want to upgrade my current Ubuntu 12.10 OS to 13.10(now please don't ask what is 13.10). this option is available from "about this computer" and many other places.the upgrade is of about 700mb to 800 MB.    BTW, i don't know why i think it's a rule here to put some question on questions asked here,however detailed or/and simple it may be.at least that's what i feel after looking at many questions. Is there a new auto-login feature? I am trying to copy multiple files named "F3.bam" two level of directories to up and then rename these files with the name of the sub-directory after copy.  For example:  /samples/mydata1/RUN1/ID_date/PCR2/TIME1/F3.bam /samples/mydata2/RUN1/ID2_date4/PCR2/TIME7/F3.bam /samples/mydataxxx/RUN1/IDxxx_datexxx/PCR2/TIMExxx/F3.bam   Expected results:  1. The files are first copied two directories level up:  /samples/mydata1/RUN1/ID_date/F3.bam /samples/mydata2/RUN1/ID2_date4/F3.bam /samples/mydataxxx/RUN1/IDxxx_datexxx/F3.bam   2. The files are renamed according to the name of the current sub-directory:  /samples/mydata1/RUN1/ID_date/ID_date_F3.bam /samples/mydata2/RUN1/ID2_date4/ID2_date4_F3.bam /samples/mydataxxx/RUN1/IDxxx_datexxx/IDxxx_datexxx_F3.bam   Ideally a bash loop would be great (working on a Mac). Is it possible to use an Ubuntu Live CD and run GParted to partition a my HDD (including the partition that is usually mounted on a given system)? I'm encountering a problem with my HDD's partitions and can't resize it. I've described my problem and my system here: .  Now, from a more general perspective, I was thinking on whether it is possible to use an Ubuntu Live CD and use GParted in a live session to possibly go around that problem. Is that possible? I made a separate question as I'm interested in the possibility independently from my current problem.  You see, I only have one partition and that's mounted. When I use GParted through Ubuntu I don't get any error reports (unlike the case reported in the question linked above).  Thanks beforehand. Is there an exception to the prohibition against ending a sentence with “ ’s ” at work here? The ’s can be used as a contraction representing a weak, unstressed word that is not pronounced.  It allegedly cannot occur in sentence final position.        She is not ready, but he is.   She’s not ready, but he is.   She’s not ready, but *he’s.      The last one is not grammatical there.  Similarly, here the last one is not grammatical:        He has not started yet, but she has.   He’s not started yet, but she has.   He’s not started yet, but *she’s.       claims this is because you cannot end a sentence with a weak form.  It backs up its point with reasonably scholarly documentation.  However, this does not seem to be invariably true.        Shall we go to the movies?  Yes, let us go.   Shall we go to the movies?  Yes, let’s go.   Shall we go to the movies?  Yes, let’s.      Unlike the third example in the first two sets, here in this case the third example is indeed grammatical, despite ending with a weak form.  Is this an exception to the rule, or is there another rule at work here? How can I remove the white pixels around the edges when exporting a transparent GIF? I took the loaders from  then exported them with the help of the included action to a GIF. But I have some white pixels around the loader which are really annoying when displayed on a dark background. You can see it here, in a frame I extracted from the gif:    How can I prevent those white pixels and maintain the transparent background? Is 512 bits a more secure hashing than 256 bits? What is the name of the first decade in a century? 80s: the "Eighties"   90s: the "Nineties"   00s: the ???   For that matter, what is the second decade called? The "tens" just doesn't sound right. Execute a command once per line of piped input? I want to run a java command once for every match of ls | grep pattern -. In this case, I think I could do find pattern -exec java MyProg '{}' \; but I'm curious about the general case - is there an easy way to say "run a command once for every line of standard input"? (In fish or bash.) Isn't $HOME supposed to be the location of the user's home directory? I'm having trouble with a web application I'm writing: The web application, which runs as user nobody, needs to launch an inkscape process to manipulate some SVG files. Because this runs as user nobody, there is no home directory. What I am doing is creating a temporary directory under /tmp and trying to set that as the home directory via export HOME=/tmp/someUniqueId. I then set a few things in that "temporary" home directory, like a symlink .fonts to the folder for the font files to use.  I know this works for finding the ~/.fonts directory. But when I launch Inkscape, all I get is a message that Inkscape could not create the .inkscape directory:    Doesn't $HOME set the location of my home directory? Why is Inkscape still trying to access / as my home directory? How can I prove that     $$1^3+ 2^3 + \cdots + n^3 = \left(\frac{n(n+1)}{2}\right)^2$$    for all $n \in \mathbb{N}$? I am looking for a proof using mathematical induction.  Thanks C++ deleting line of text in a file How to disable GNOME keyring? I want to disable GNOME keyring globally on my machine. So I deleted the lines  auth    optional        pam_gnome_keyring.so session optional        pam_gnome_keyring.so auto_start   in /etc/pam.d/gdm. It seems to me that this has no effect. When I lock in the syslog writes  Aug 24 18:37:03 foobar gnome-screensaver-dialog: gkr-pam: unlocked login keyring   and another user sees a menu window where he hs to enter his credentials. So what is the correct way to disable keyring for every user on that machine? How to work the BibTeX? I have searched the tutorials but have not been successful in understand them. The tutorials always mensionam concepts that I do not know. I would like to understand the basics of BibTeX.  By basics I mean:   How do I install BiBTeX? How to build a file in bib? For this question assume that I already have the bibtex format each reference provided by databases like MathSciNet. See observation 1 below. What I write commands in the file format. Tex to call call the format file bib? How to exploit the format of the bibliography that comes out in PDF? The commands are made in the preamble of the file. Arquifo bib or format. Tex? What must be the BiBTeX with biblatex? Is there any tutorial (in pdf or video) that teaches step by step how to operate BiBTeX?   Observation 1 I already have the bibtex format each reference provided by databases like MathSciNet:   @article {MR2373353,  AUTHOR = {Avila, Artur and Lyubich, Mikhail},  TITLE = {Hausdorff dimension and conformal measures of {F}eigenbaum {J}ulia sets},  JOURNAL = {J. Amer. Math. Soc.},  FJOURNAL = {Journal of the American Mathematical Society},  VOLUME = {21},  YEAR = {2008}, NUMBER = {2},  PAGES = {305--363},  ISSN = {0894-0347},  MRCLASS = {37F35 (37F10 37F25)},  MRNUMBER = {2373353 (2009i:37112)},  MRREVIEWER = {Feliks Przytycki},  DOI = {10.1090/S0894-0347-07-00583-8},  URL = {http://dx.doi.org/10.1090/S0894-0347-07-00583-8}, } Should I mention my Canadian visa refusal in my UK visa application? Strange object.ray_cast() behavior object.ray_cast() is not behaving as I would expect in Blender 2.77. I understand that it expects object local coordinates, but this problem happens when the object is not translated, rotated, or scaled.  If I edit the shape of the cube mesh without moving the cube, the results of ray_cast() seem plain wrong.  Steps to reproduce   Create a cube at 0,0,0 Move a vertex of the cube from 1,1,1 to 5,5,5 Create an empty called "src" at 2,2,2 Create an empty called "dst" at 2,2,6   Run this python  cb = bpy.data.objects['Cube'] src = bpy.data.objects['src'] dst = bpy.data.objects['dst'] hit, loc, norm, face = cb.ray_cast(src.location, dst.location) bpy.ops.object.empty_add(location = loc)   This is the result on my system. The new Empty created at the interesection point is selected:    The source and the destination are both at x = 2 and y = 2. The cube has a surface at x = 2 and y = 2. So why on earth is the intersection point at x = 2.22222, y = 2.22222? Why does Ubuntu force users to create a password upon installation? Should my first trip be to the country which issued my Schengen Visa?