I read  but I cannot really get the difference. I am running zsh 5.4.2 on 64-bit debian-buster. Both which and whence are shell-builtins .   Can people point out where whence would be more appropriate than which and vice-versa ?  /home/shirish&gt; zsh --version zsh 5.4.2 (x86_64-debian-linux-gnu)  /home/shirish&gt; type -a which which is a shell builtin which is /usr/bin/which which is /bin/which  /home/shirish&gt; type -a whence whence is a shell builtin
When looking for the path to an executable or checking what would happen if you enter a command name in a Unix shell, there's a plethora of different utilities (which, type, command, whence, where, whereis, whatis, hash, etc).  We often hear that which should be avoided. Why? What should we use instead?
I need help making a TRIGGER that compares two dates being entered into a table, but I'm not 100% on the syntax I should use.  Something like:  CREATE TRIGGER chk_dates    BEFORE INSERT ON `job_history`    FOR EACH ROW     BEGIN       IF( NEW.end_date &lt; OLD.start_date ) .../// error, don't insert data       ELSE .../// allow the data to be entered   My table job_history will have a start_date, and when end_date is entered, I want it to check to ensure that it isn't prior to start_date.    How do I accomplish this? How to find image coordinates of the rendered vertex? I have a simple mesh of a cube.  I would like to know what are the coordinates of each vertex in the rendered image (i.e. for each 3d vertex I'd like to know it's pixel coordinates).  Is there a way to do this?  Clarification:  I'm experimenting with a pose estimation algorithm (i.e. finding out the 3d pose of the object) from a (set of) 2d image(s).  Instead of taking an image of a real object with a real camera I synthetically render the image of a cube using blender.  In this way I know the pose of the object and the intrinsics of the camera, so I can easily validate the results of the pose estimation algorithm. Pose estimation algorithms usually require to provide them with world points on the object and the corresponding image points.  So what I'm looking for is a way to produce a dump of correspondences of the 3d point &lt;--> image point as a byproduct of the rendering procedure. Thanks, Alex How to remove the WordPress version from some .css/.js files I know that I can use the following function to remove the version from all .css and .js files:  add_filter( 'style_loader_src', 'sdt_remove_ver_css_js', 9999 ); add_filter( 'script_loader_src', 'sdt_remove_ver_css_js', 9999 ); function sdt_remove_ver_css_js( $src ) {     if ( strpos( $src, 'ver=' ) )         $src = remove_query_arg( 'ver', $src );     return $src; }   But I have some files, for instance style.css, in the case of which I want to add a version in the following way:  function css_versioning() {     wp_enqueue_style( 'style',         get_stylesheet_directory_uri() . '/style.css' ,         false,         filemtime( get_stylesheet_directory() . '/style.css' ),         'all' ); }   But the previous function removes also this version. So the question is how to make the two work together? Boggle: What is the dice configuration for Boggle in various languages? This is the dice configuration for the English Boggle:  Other variants and discussions concerning letter distributions for English can be found here:  , , ,  (Wikipedia).  I am interested in the 16 dice configurations for also other languages (Spanish in particular) and I am unable to find it anywhere online.  Versions I have managed to find so far:  ,  English 25 dice version:   Spanish 25 dice version:   Italian 25 dice version: image of polynomial map is not an algebraic set I am doing an exercise about algebraic geometry, where the exercise  tell us to provide example of the image of polynomial map $f:\mathbb{C}^{m}\rightarrow \mathbb{C}^{n}$ that is not an algebraic set. But I am thinking that the image of every polynomial is $\mathbb{C}$ thus every polynomial map is surjective. What have I misunderstand? When editing a question on , I observed that a link which was not rendered in the post was hyperlinked in the edit preview (see pictures below). I tried reproducing it in the  to see if this also happens when the post is posted for the first time and observed the same. It seems to be a bug after the shift to CommonMark, leading to the different rendering of links on client and server-side. A link following a special character (without any space) is not hyperlinked in the post but is hyperlinked in the preview. A link separated from the special character with a white space appears to have no such problem. (see pictures below and my ). Link not hyperlinked in post  Same link hyperlinked in preview Prove that the dihedral group $D_4$ can not be written as a direct product of two groups Has Marvel commented on the extra Infinity Gauntlet? If a variable is declared as static in a function's scope it is only initialized once and retains its value between function calls. What exactly is its lifetime? When do its constructor and destructor get called?  void foo()  {      static string plonk = "When will I die?"; } I wonder is it legal to register a domain name that contains a company name. For example cococola.cc (considering that this domain name is available). Can I buy and use any domain names that contain a name of a trademark? How can I disable the “News and Interests” Widget on the Windows 10 Taskbar? On Windows 10 version 1909 and newer releases, Microsoft has added a &quot;News and Interests&quot; widget on the Taskbar (see ):  How can I remove this Widget from the Taskbar? Flagging multiple comments versus flagging the whole post for moderator attention When multiple comments in a comment thread ought to be removed (especially if they're all for the same reason), should I flag each of them individually or flag the parent post for moderator attention?  I've usually adopted the former strategy - flagging each comment with the same flag reason, often a custom one copied and pasted. I had always assumed the following things that led me to follow this strategy:   Flagged comments were discretely marked as flagged in some way when the reviewer viewed the question (much like how I can see others' pending suggested edits now that I have editing privileges). By individually flagging all the comments that needed cleaning up, I was allowing the flag reviewer to see at a glance which comments needed removing, thereby providing them with useful additional information that wouldn't be available if I flagged the entire parent post. By flagging comments individually, rather than flagging the whole post, I was letting my flags be handled by anyone with 10k+ rep and access to the mod tools, rather than having to be handled by a diamond moderator.   However, I just read  (now deleted) by Shog9 that makes me suspect that approach is misguided, and question whether any of my assumptions about how comment flags work are actually true. Notably he says:     If you'd pinged me once for every comment in that thread you found noisy, I would probably be plotting my revenge instead - at very least, I would think you very rude for doing so. Yet, that's exactly what you're doing when you start flagging multiple comments in a single thread: instead of taking a few seconds to describe a problem, you're attempting to use a moderator as a tool to do your bidding, without any real effort to communicate.   He also said some more stuff on the topic - I think there was something about huge offensive boxes blotting out the UI when he views questions with multiple flags - but I now can't recover it any more because that question was deleted while I was in the process of writing this one, and it doesn't seem to be available in the Google cache.  Much of the flagging and review system is still a black box to me as a low/mid rep user, and it's difficult for me to figure out what flagging behaviors are appropriate and helpful when I have no idea what actually happens when I flag a comment. (The Privileges section doesn't mention comment flags anywhere that I can find. I don't even know who reviews them at the moment, and can't find a Meta question anywhere that addresses that.)  Could somebody provide some input on when (if ever) flagging lots of individual comments in a thread is appropriate, and when flagging the entire parent post is? A pretty screenshot of the UI of the relevant review/mod tools, demonstrating the effect of each approach, might also be helpful for understanding this, if that's not asking too much. Limiting floats to two decimal points Can I get UAC prompt for user from batch file? Can I get UAC prompt for user from batch file?  For example I need put some keys to registry under CurrentControlSet from batch file by     reg import path\to\my.reg   PS. runas is not a solution as my customers uses different Windows localisation and I can not guess which name used for Administrator account (this can be Администратор)...  And script don't know administrator password.  And UAC dialog box does not require password entering... IMAP: how to move a message from one folder to another (using the IMAP commands, not with the assistance of any other mail package) Prove that for $ 0&lt;x&lt; \pi $, $$ \quad S_n(x) = \sin x + \frac{ \sin3x }{3} + ... + \frac{ \sin((2n-1)x) }{2n-1} &gt;0 \quad \forall n = 1,2,... $$  Having trouble with this problem. This is an olympiad-style question, so an answer that doesn't use calculus or analysis would be preferred. A possible approach is induction, but for this we need to find a function in terms of $n$ and $x$ so that we can actually use the inductive step. If anyone has any ideas they would be appreciated.  If you really want to go down the calculus route (at this point I don't mind), then $ S_n' (x) = \cos x + \cos 3x + ... +\cos((2n-1)x) $ , which you can find a closed form for, but I don't know how useful that is. How to preserve non-ASCII characters in ogr2ogr import? Can you explain the "Axiom of choice" in simple terms? Representing every positive rational number in the form of $(a^n+b^n)/(c^n+d^n)$ About a month ago, I got the following :      For every positive rational number $r$, there exists a set of four positive integers $(a,b,c,d)$ such that    $$r=\frac{a^\color{red}{3}+b^\color{red}{3}}{c^\color{red}{3}+d^\color{red}{3}}.$$      For $r=p/q$ where $p,q$ are positive integers, we can take    $$(a,b,c,d)=(3ps^3t+9qt^4,\ 3ps^3t-9qt^4,\ 9qst^3+ps^4,\ 9qst^3-ps^4)$$   where $s,t$ are positive integers such that $3\lt r\cdot(s/t)^3\lt 9$.      For $r=2014/89$, for example, since we have $(2014/89)\cdot(2/3)^3\approx 6.7$, taking $(p,q,s,t)=(2014,89,2,3)$ gives us $$\frac{2014}{89}=\frac{209889^3+80127^3}{75478^3+11030^3}.$$   Then, I began to try to find every positive integer $n$ such that the following proposition is true :   Proposition : For every positive rational number $r$, there exists a set of four positive integers $(a,b,c,d)$ such that $$r=\frac{a^\color{red}{n}+b^\color{red}{n}}{c^\color{red}{n}+d^\color{red}{n}}.$$  The followings are what I've got. Let $r=p/q$ where $p,q$ are positive integers.   For $n=1$, the proposition is true. We can take $(a,b,c,d)=(p,p,q,q)$. For $n=2$, the proposition is false. For example, no such sets exist for $r=7/3$. For even $n$, the proposition is false because the proposition is false for $n=2$.   However, I've been facing difficulty in the case of odd $n\ge 5$. I've tried to get a similar set of four positive integers $(a,b,c,d)$ as the set for $n=3$, but I have not been able to get any such set. So, here is my question.     Question : How can we find every odd number $n\color{red}{\ge 5}$ such that the following proposition is true?      Proposition : For every positive rational number $r$, there exists a set of four positive integers $(a,b,c,d)$ such that $$r=\frac{a^n+b^n}{c^n+d^n}.$$   Update : I posted this question on .  Added :  asks the case $n=3$. Probability of area being greater than 0.5 with random lines