Correct way to quote variables for use in Bash backticks? I have a script which I want to go over 4 sets of files PURO*.xml, PURR*.xml, SALO*.xml and SALR*.xml.  for j in PUR SAL do         mask=("${j}O*.xml" "${j}R*.xml")         for k in 0 1         do                 for file in `find ${CDIR} -maxdepth 1 -daystart -mtime ${MTIME} -and -name ${mask[$k]} | xargs`   The script works, however, when it is executed, if the working directory has files that match one of the mask, that mask gets expanded.  Question is, what would be the correct way to write the above piece of script so that mask is passed correctly to find command? I want "${j}" expanded at the point where I create mask, but not the "*".  Also, is backticked find OK or should I perhaps rewrite that part differently as well?
Why does my shell script choke on whitespace or other special characters? Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?
Proof by induction that if $n \in \mathbb N$ then it can be written as sum of different Fibonacci numbers Proof that every natural number $n\in \mathbb N$, can be written as the sum of different Fibonacci numbers between $F_2,F_3,\ldots,F_k,\ldots$.  For example: $32 = 21 + 8+3 = F_8+F_6+F_4$  Research effort:  The base step it's simple:  Let $k=1$ it can be britten as $k=1=F_2$  For the inductive step I considered:  Let $k = k  F_2 =F_2+F_2+\cdots+F_2 = \sum_{i=2}^w a_iF_i, a_i =\{0,1\} $  Then if $k$ suffice I want to see if $k+1$ suffices too... But I'm not realy seeing how to use the inductive hypothesis, so I assume It's wrong.  Any thoughts on which can the inductive step be? How can I use only the external flash on slave mode without firing the built-in flash? I have a Canon 700D and YN-568EX ii external flash that I am using in slave mode. But whenever I try to fire the built-in flash pops up automatically and fires itself. Is there any option to use only external flash? JavaScript 64 bit numeric precision Is there a way to represent a number with higher than 53-bit precision in JavaScript? In other words, is there a way to represent 64-bit precision number?  I am trying to implement some logic in which each bit of a 64-bit number represents something. I lose the lower significant bits when I try to set bits higher than 2^53.  Math.pow(2,53) + Math.pow(2,0) == Math.pow(2,53)   Is there a way to implement a custom library or something to achieve this? How do you use a variable in a regular expression? macOS Mojave won't install updates past 10.14.1 due to requirement for APFS formatting I have a MBP 2012 I upgraded from High Sierra to Mojave after it came out as GA. I don't recall if I was asked about upgrading to APFS when Id id that, but at this time the main volume is Mac OS Extended (Journaled).  My current About This Mac...version is Mojave 10.14.1 (18B75). Now, when updates are advertised from the App Store, I'm unable to upgrade because 10.14.3 is required.  No OS updates show in the App Store, and when I searched for the updaters (10.14.2 Combo, etc), I can't install because the installer reports "macOS 10.14.2 Update can't be installed on this disk. This Mac can only install macOS on APFS-formatted drives."  I tried the search results recommending to boot in Recovery Mode and use Disk Utility, but APFS is not available as a type.  I have good backups and I can reformat the boot volume if I need to, but I have not done this before. Should I get a 10.14.3 installer to do this and boot from an external drive? The only guies and message boards I've found just keep saying to install 10.14.3 (I can't) or convert the disk in Recovery Mode (APFS is not available as an option.)  Any known-good ways to get my 10.14.1 upgraded so I can keep getting App Store updates? K out of N encryption Displaying intersecting roads and creating multiple labels for long roads in QGIS? I am new to GIS and I am using QGIS 1.7.3 on Windows.  Can any one tell me how to display a map from line shapefile with these two characteristics:   Roads are displayed with borders at the sides and intersect at crossroads Name label for long roads are duplicated at specified intervals   Here is the link to an image that illustrates my idea:    (The map was taken from underdark's blog)  This is the best I can achieve by drawing lines with two overlapping simple line, one slightly bigger than the other: Anonymous user feedback now in testing Anonymous and unregistered users with &lt; 15 reputation (the amount required to earn the upvote privilege) will now see       feedback   on every post in the area that a logged in user would see "add comment":    When the post area is moused over, the area expands to:     Was this post useful to you? [Yes] [No]     once clicked it will say     sending feedback...   and eventually     Thank you for your feedback.   The goal is to offer the 90% of our traffic that is anonymous users a way to provide more meaningful feedback on posts rather than passively incrementing a view counter.  This click data is currently being evaluated to see what we can do with it. Ideas welcome! Proving that $a \mathbb{Z} \cap b\mathbb{Z} = \operatorname{lcm}(a,b)\mathbb Z$ Given $m \in \mathbb{Z}$, let $m\mathbb{Z}$ denote the set of integer multiples of $m$, i.e. $m\mathbb{Z} := \{mk\mid k \in \mathbb{Z}\}$.   Now let $a,b \in \mathbb{Z}$ with $a,b$ not both $0$. Prove that $a\mathbb{Z} \cap b\mathbb{Z} = \operatorname{lcm}(a,b)\mathbb{Z}$.   I am trying to write a proof for this, but I am unsure of what method to use. Also I am confused by $mk\mid k$, because wouldn't $m=1$ for this to be true. Using 'do' unnecessarily Often when I am on a flight, nearly every sentence I hear from the flight attendants contains an unnecessary emphatic auxiliary in its main clause; that is, an altogether unnecessary do or unnecessary emphasis on other auxiliaries:     We do apologise for the delay, which was due to technical issues, but we will be taking off shortly, and we do hope you enjoy the flight. We do ask you to fasten you seatbelt now, and if you do have any questions, we do hope you won't hesitate to ask us.   What is the purpose of this constant emphasis? My guess is it's supposed to somehow elevate their language to a higher register, but why do flight attendants in particular seem so fond of this? Changing the homepage Do comic characters sometimes get drawn like the actor playing them? I noticed in Spider-Man's recent cameo in Captain Marvel, he appeared an awful lot like Andrew Garfield who is playing Spider-Man in the recent movie.    Irrelevant of whether it is just my imagination, do some depictions of comic characters morph to be more like an actor who plays them around the time a corresponding movie is released?  By comparison, here is Spider-Man's depiction in the Spider-Men crossover: I can't change materials I was making a scene in blender and I wanted to change the texture from "Material_1" to "Material_2". It lets me change it but when I go to rendered view the part looks the same. can someone please help me I have equations inside an environment which has a larger left-margin than the main text (analogous to an enumerate/itemize environment, implemented with the changepage package's adjustwidth environment). Just as equations in enumerate/itemize behave, the equations are centered with respect to the entire text, rather than just the width of the container environment. I want the latter behavior.  I'm trying to accomplish this by wrapping all display-math in minipages. Namely, I'm modifying the mathdisplay environment in amsmath.sty as follows:  \makeatletter \let\oldmd\mathdisplay \def\mathdisplay#1{%   \newline   \begin{minipage}{\textwidth-\@totalleftmargin}%     \oldmd{#1}% } \let\oldendmd\endmathdisplay \def\endmathdisplay#1{%   \oldendmd{#1}%   \end{minipage} } \makeatother   This is almost working, but there are some issues with spacing which I don't understand how to fix. Here's how the the normal \[ ... \] and numbered \begin{equation} ... \end{equation} look with the above modification:      My main confusion is why the numbered version is behaving so differently from the unnumbered. But all in all I want to fix this so that the spacing above and below is even as it usually is. Any help is appreciated, thanks.  Edit: Here's a compilable example:  \documentclass{amsart}  \usepackage{lipsum} \usepackage{calc} \usepackage{changepage}  \makeatletter \let\oldmd\mathdisplay \def\mathdisplay#1{%   \newline   \begin{minipage}{\textwidth-\@totalleftmargin}%     \oldmd{#1}% } \let\oldendmd\endmathdisplay \def\endmathdisplay#1{%   \oldendmd{#1}%   \end{minipage} } \makeatother  \setlength{\parindent}{0pt}  \begin{document}  \lipsum[1]  \begin{adjustwidth}{20pt}{} \lipsum[2] \[ x \mapsto \hom(-,x) \]  \lipsum[3] \begin{equation}   y \mapsto \hom(y,-) \end{equation} \lipsum[4] \end{adjustwidth}  \lipsum[5]  \end{document} Electricity takes the path of least resistance? Electricity takes the path of least resistance!   Is this statement correct?    If so, why is it the case?  If there are two paths available, and one, for example, has a resistor, why would the current run through the other path only, and not both? "Seen" status is earlier than the user's last post I posted what I think is a clever answer to:    But then I noticed the question was posted a while ago on Mar 2.  I wanted to see what the chance of the user logging back in and seeing my answer, but the  says the user was seen on Feb 19.  I thought this was supposed to be the date they last logged in? How could they have asked a question on Mar 2 if they haven't logged in since February?  Thanks Can I change some but not all Apple keyboard function keys (dim vs F1, bright vs F2)? I want to override F1 and F2 behavior, since I have external display and Mac can't control display's brightness. The rest of the keys should retain their non Fx  I know about "Use all F1-F12 keys as standard function keys.", but I don't want to change all of the keys to be F when pressed, just some of them. (For me single press music and volume control is necessary.)  Is there a way to pick some of the function keys to default to numbered function instead of the "Apple" definitions system wide? Parsing JSON from URL String manipulation with & or + in VB.NET Allow all reviewers to see deleted posts they reviewed So moderators just got . Often, these bans are due to specific very bad reviews, like approving spam or non-answers. It will be common for us to give links to these bad reviews in the ban message that the reviewers will be presented with.  However, many of these reviewers lack the necessary reputation to see deleted posts. If we're banning someone from review for approving spam or non-answers, almost all of the time those posts will be deleted. If we give them links to the reviews they performed, they won't see the now-deleted posts that they approved, and won't have a chance to learn what they did wrong.  As examples of this, I had to actually take a screenshot to show the reviewers  and  the posts that triggered their ban, because they could no longer see them.  I propose that reviewers of any reputation level be able to see posts that they reviewed, even ones that were later deleted, if they are presented with a link to their review. They already saw the post once, so there's no harm in showing it to them again, and reviewers are going to need to see why they made a bad call on a particular review.