Is "neither have I wings to fly" grammatically correct?
"He added" vs. "Did he add" (inversion after negative adverb)
How much web can Spider-Man produce? Get last insert id after a prepared insert with PDO I've been using mkvmerge to merge a video file and subtitles, I'm using the following command  mkvmerge -o output.mkv video.mp4 subtitles.srt   Which is working fine but as you can probably guess this is really slow operation   I've to open terminal in every one of those directories where movies are stored. Then I've to copy and paste the names of the files in the command Then I've to rename the output file Then delete the original files which I used   This is a lengthy process.     Ideal situation that I want.   I'll go into the folder which contains a movie file and a subtitle file with the same name. I select a movie file and and a subtitles file, right click and run a nautilus script on them. They get merged Original file gets deleted. Rename the merged file with the name of the orignal file with mkv extension      This doesn't need to be recursive, I don't want my HDD creating and deleting 100's of files at ones. Movie files and Subtitle files generally have the same name but some times have "_en" post fixed to subtitle files. If you have another approach of doing it I'm on board with that too. Why are login forms centered? Why are login forms always centered on the screen? Most horizontally, some vertically also. Sites like Apple/Amazon/Adobe/Microsoft/Google/PayPal/Instagram/Twitter etc. are all centered! Is this an undocumented best practice everyone unanimously decided to use?         &ndash; Wireframes created with   Obviously it's most aesthetically pleasing, but is there any other reasons why?  Edit: Many of these sites do not support mobile either, so it wasn't done specifically for that. When two phrases are pronounced alike but have different spelling and meaning, can we call them homophones?  e.g. "ice-cream" and "I scream", "nitrate" and "night rate", "that's tough" and "that stuff".  Or is there another term for them?  What linguistic phenomenon distiguishes these near homophones?  I've checked the putative duplicate at  but it isn't exactly what I'm asking here. Simulating the Windows key on an old keyboard I am trying to show $$\lim_{n\rightarrow \infty} \int_{[0,1]^n} \frac{|x|}{\sqrt{n}}dx=\frac{1}{\sqrt{3}}$$ where $[0,1]^n$ is the unit cube in $\mathbb{R}^n$. I would appreciate any hint. What does "sudo apt-get update" do? I am wondering what sudo apt-get update does?  What does it update? How to select an element whose id is dynamic and keeps changing There is a type and search drodown which will appear after user type in the value. I need to click on the dropdown which contains the name of the drop down field.   The problem here is that there is no unique attribute present (No unique class, no unique name) &amp; the id keeps on changing after every login so cannot take id also. Given fields $M/E/F$, why does $[M:F] = [M:E][E:F]$? Let $M$ be a finite extension of $E$ and let $E$ be a finite extension of $F$. Then $M$ is a finite extension of $F$ and $[M:F] = [M:E][E:F]$.   Is there an easy explanation and/or proof for this theorem? My instructor gave an incomplete proof in class but got stuck and I'm kind of confused of what's going on. $$f(x,y) = \begin{cases} 2 &amp; 0&lt; x&lt; y&lt;1  \\     0 &amp;\text{otherwise} \end{cases} $$  I need to find   the density function of $y$ and conditional pdf of $X$ given $Y$.   My answer is coming out to be   $2y$ $\frac1y$ I used Sound Juicer to rip a CD of audio for a language learning book so that I could listen to them on my Android. However, Sound Juicer seems to only have the option of numbering files without leading zeros. Like this:  track_1.mp3 track_10.mp3 track_11.mp3   This leads to some confused ordering on my music player. So, I want to add some zeros to the name, so that they're ordered properly, like this:  track_01.mp3 track_02.mp3 track_03.mp3   How do I accomplish this? I tried using GPRename, but while it has the ability to add numbers, it doesn't seem to have any options for adding leading zeros.  Is there a better program or something I can do at the command line? factorization of a^n+1? I'm trying to prove that $a^n+1$ can only be prime if $n$ is a power of $2$. Is there a general factorization of $a^n+1$? Given that the majority of biologists do not currently consider viruses to be alive, a virus can never die.  It can, however, get destroyed by long exposures to soapy water, alcohol, and apparently certain frequencies of UV light.  Why is an individual SARS-CoV2 virion not infectious forever?  Or is it? Why is df -h size, util and dispo not corresponding to each other When I'm using the command "df -h" I'm having the following output :   Filesystem                 Size   Used  Avail Use% Mounted on /dev/mapper/fedora-root    20G    9,4G  8,8G  52% / devtmpfs                  1,9G       0  1,9G   0% /dev tmpfs                     1,9G    1,2M  1,9G   1% /dev/shm tmpfs                     1,9G    1,0M  1,9G   1% /run tmpfs                     1,9G       0  1,9G   0% /sys/fs/cgroup tmpfs                     1,9G    108K  1,9G   1% /tmp /dev/sda1                 477M    129M  319M  29% /boot /dev/mapper/fedora-home   916G    279G  591G  33% /home   Or it says my root is of 20G with 9.4 used and 8.8 still available it's 2G that disappeared. I know a very similar question as been answered here  and I'm just wondering if the reason could be the same here since I'm using LVM.  If not is there any way to reclaim that space that disappeared because for home there is an amazing 46G that disappeared. Magic quotes in PHP According to the , in order to make code more portable, they recommend using something like the following for escaping data:  if (!get_magic_quotes_gpc()) {     $lastname = addslashes($_POST['lastname']); } else {     $lastname = $_POST['lastname']; }   I have other validation checks that I will be performing, but how secure is the above strictly in terms of escaping data? I also saw that magic quotes will be deprecated in PHP 6. How will that affect the above code? I would prefer not to have to rely on a database-specific escaping function like mysql_real_escape_string(). I'm trying to understand a "subproof" of the divisor Master Theorem (Cormen et al., Introduction to Algorithms, page 99), and in some point they state:  $$\Large a^{\log_b n} = n^{\log_b a}$$  where $a\geq 1$, $b &gt; 1$ and $n = b^i$, for some $i$. That is, $n \in \{1, b, b^2, ...\}$  I would appreciate a simple explanation of this equality (just OK for a CS undergraduate). Symmetrical twin paradox in a closed universe Take the following gedankenexperiment in which two astronauts meet each other again and again in a perfectly symmetrical setting - a hyperspherical (3-manifold) universe in which the 3 dimensions are curved into the 4. dimension so that they can travel without acceleration in straight opposite directions and yet meet each other time after time.  On the one hand this situation is perfectly symmetrical - even in terms of homotopy and winding number. On the other hand the Lorentz invariance should break down according to , so that one frame is preferred - but which one?  So the question is: Who will be older? And why?  And even if there is one prefered inertial frame - the frame of the other astronaut should be identical with respect to all relevant parameters so that both get older at the same rate. Which again seems to be a violation of SRT in which the other twin seems to be getting older faster/slower...  How should one find out what the preferred frame is when everything is symmetrical - even in terms of GRT?  And if we are back to a situation with a preferred frame: what is the difference to the classical Galilean transform? Don't we get all the problems back that seemed to be solved by RT - e.g. the speed limit of light, because if there was a preferred frame you should be allowed to classically add velocities and therefore also get speeds bigger than c ?!? (I know  is only a local theory but I don't understand why the global preferred frame should not 'override' the local one).  Could anyone please enlighten me (please in a not too technical way because otherwise I wouldn't understand!)  EDIT Because there are still things that are unclear to me I posted a follow-up question: What is the correct formula for gravitational time dilation for a satellite in a circular orbit? How to import a module given the full path? How can I load a Python module given its full path? Note that the file can be anywhere in the filesystem, as it is a configuration option.