Double-quoting (vs not) variables in [ and [[
Why does parameter expansion with spaces without quotes work inside double brackets "[[" but not inside single brackets "["?
Styling each feature of a layer individually I’ve a PostGIS table which is published as a Geoserver layer. Every feature in the table has some attributes that should style that feature (e.g color, size, opacity, external graphic url, ... etc).  I can create an SLD document and let it read its styling attributes from the table using &lt;PropertyName&gt;, but the problem is more complex than this, for example: some points features need to be styled as a simple circles, while some other need to be styled as external-graphic images. And from the SLD Reference, the SLD PointSymbolizer must have either &lt;Mark&gt; or &lt;ExternalGraphic&gt; element, for that reason I should create two rules one for the simple point symbolizer and the other for the external-graphic point symbolizer, and should add a filter to each rule so that it deals only with the appropriate features, something like:  &lt;FeatureTypeStyle&gt;     &lt;Rule&gt;         &lt;ogc:Filter&gt;             &lt;ogc:PropertyIsEqual&gt;                 &lt;ogc:PropertyName&gt;is-external-graphic&lt;/ogc:PropertyName&gt;                 &lt;ogc:Literal&gt;0&lt;/ogc:Literal&gt;             &lt;/ogc:PropertyIsEqual&gt;         &lt;/ogc:Filter&gt;         &lt;PointSymbolizer&gt;             &lt;Graphic&gt;                 &lt;Mark&gt;                     &lt;WellKnownName&gt;circle&lt;/WellKnownName&gt;                     &lt;Fill&gt;                         &lt;CssParameter name="fill"&gt;                             &lt;ogc:PropertyName&gt;fill-color&lt;/ogc:PropertyName&gt;                         &lt;/CssParameter&gt;                     &lt;/Fill&gt;                 &lt;/Mark&gt;                 &lt;Size&gt;6&lt;/Size&gt;             &lt;/Graphic&gt;         &lt;/PointSymbolizer&gt;     &lt;/Rule&gt;     &lt;Rule&gt;         &lt;ogc:Filter&gt;             &lt;ogc:PropertyIsEqual&gt;                 &lt;ogc:PropertyName&gt;is-external-graphic&lt;/ogc:PropertyName&gt;                 &lt;ogc:Literal&gt;1&lt;/ogc:Literal&gt;             &lt;/ogc:PropertyIsEqual&gt;         &lt;/ogc:Filter&gt;         &lt;PointSymbolizer&gt;             &lt;Graphic&gt;                 &lt;ExternalGraphic&gt;                     &lt;OnlineResource                xlink:type="simple"                xlink:href="smileyface.png" /&gt;                     &lt;Format&gt;image/png&lt;/Format&gt;                 &lt;/ExternalGraphic&gt;                 &lt;Size&gt;6&lt;/Size&gt;             &lt;/Graphic&gt;         &lt;/PointSymbolizer&gt;     &lt;/Rule&gt; &lt;/FeatureTypeStyle&gt;   My question is: Is there any better solution that is more dynamic? What's the maximum value for an int in PHP? Ignoring the special libraries that allow you to work with very big numbers, what's the largest int value you can store in PHP? Installing nvidia drivers on 18.04 Additive group contains exactly three elements of the set $\{p,p+q,pq,p^q,q^p\}$ Windows shortcut (.lnk) parser in Java? I'm currently using Win32ShellFolderManager2 and ShellFolder.getLinkLocation to resolve windows shortcuts in Java. Unfortunately, if the Java program is running as a service under Vista, getLinkLocation, this does not work. Specifically, I get an exception stating "Could not get shell folder ID list".  Searching the web does turn up mentions of this error message, but always in connection with JFileChooser. I'm not using JFileChooser, I just need to resolve a .lnk file to its destination.  Does anyone know of a 3rd-party parser for .lnk files written in Java I could use?  I've since found unofficial documentation for the .lnk format , but I'd rather not have to do the work if anyone has done it before, since the format is rather scary. I was wondering in C++ if I have an enum can I access the value at the second index?  For example I have  enum Test{hi, bye};   if I want 'hi', can I do something like Test[0], thanks. Emmy Noether's theorem in simpler terms I'd like to understand  and its contents as to what it implies in a bit simpler terms. I am familiar with mathematics unto Calculus 1,2,3 and some linear algebra and group theory. I am familiar with that for each symmetry there is a conservation law.    Now is there a one-one correspondence between these two always? What about laws like conservation of charge?  And conservation of energy?  And conservation of mass?  Considering our view of nature was changed as Special Relativity was introduced and thus, what earlier the theorem would have asserted as mass and energy to be originating from different symmetries then how did we reconcile these two as just one symmetry? Can I install Windows OS (Windows 7) on a removable USB hard drive? I wanted to take a sneak peek at Windows 7 so I thought of installing it. I have Windows Vista on my laptop which came pre-installed with it. I didn't want to mess with it.  So I created a partition (20 GB) in my USB external hard disk and tried to install Windows 7 on that partition. But when I booted from a Windows 7 DVD and selected the target partition on USB hard disk, it said it cannot be installed.  Is there any way to install Windows on an external USB hard disk? Refresh thumbnails in nautilus How does one refresh thumbnails in nautilus? In my videos folder I have some MKVs and only half of them have the movie border and a excerpt from the movie and the others (also MKVs encoded in the same way) just have the ordinary film icon.  (F5 doesnt do it.) I cannot respond to comments on my own question (no "add a comment" link anywhere) I joined a new community and asked a question ()  People are commenting &amp; asking questions, but I cannot answer them back. Even "Comment Everywhere" privilege requires 50 reputations and I have 101 reputations.  Am I missing something? How did the Tesseract come to Earth from Asgard? Adding layers to GeoPackage using PyQGIS Does the fact that matrices $A, B$ are similar imply that $A+cI$ is similar to $B+cI$? Let $A, B$ be similar $n \times n$ matrices over (say) $\mathbb{R}.$  Is it the case that $A+cI$ is similar to $B+cI$?    Here is an argument (which seems too good to be true...)  Since $A, B$ are similar, they have the same Jordan form. So we can write $PAP^{-1}=QBQ^{-1}=J$ for $P, Q$ invertible matrices.   Hence we have $P(A+cI)P^{-1}=PAP^{-1}+cI= J+cI.$ Similarly, we find $Q(B+cI)Q^{-1}=J+cI.$  Hence $A+cI$ and $B+cI$ are both similar to $J+cI$ and hence similar to each other.   Is this correct? What's the difference between "I love singing" and "I love to sing"? I would like to know what the difference is between "I love doing something" and "I love to do something".  For example:        “I love singing.”      and,        “I love to sing.”      When I was young, I was told that "love doing something" is right, but one day, I found Jessie J wrote "I love to sing" on her Instagram. How do filament LED bulbs work, looking very similar to incandescent bulbs? Filament LED bulbs use very narrow strips containing the LED, which look similar to filaments of an old incandescent bulb:  They look like a normal bulb with large "old-style" coal filaments, and are of about the same size and shape as the common standart E27 socket bulb.    There are two basic variants of these bulbs:     One "plain" as described, looking impressively similar to a classic bulb The other has a white coating on the glass, about 15mm wide next to the metal socket.   How are these filaments build? I could imagine the it's "pretty normal" LEDs, but lots of them, directly bonded to something? (There are references to COB)  How does the heat management work? Ii have seen speculations about filling the bulb with either helium or "some patented organic gas" - could that be enough for cooling?  How does the driver - which seems to be very small - work?  In the variant with white coating - hiding some components, I assume - is already not that much space, and in the plain variant, there seems to be almost no space for something nontrivial.  Below you see some bulbs of the white coating variant, switched on:   (Images with the permission of this )    Note how the LED filament bulbs are not so much similar to the tungsten filament bulbs recently being phased out - they are more resembling the long outdated carbon filament bulbs: Rigorous proof that surjectivity implies injectivity for finite sets Does anyone know of a program or way to log all network activity to a specific program on one's computer (program and/or service)?  I know I can see this "live" in Resource Monitor, but I'm wondering if anyone knows of a program or way to track and log all network activity to/from a specific process and/or service.  I'm finding a lot of "live"-type monitors, like Windows Resource Monitor, but nothing that can log. Where are the outliner toggles in 2.8? The selection toggle arrows in the Outliner disappeared. Is there some preference in the settings that has to be turned on? I am using longtable and I cannot find a way to adjust its column spacing. I want a table like this:    But I am getting this:    This is what I am doing for defining table size:   \begin{longtable}{p{.1\textwidth} p{.2\textwidth} p{.2\textwidth}p{.3\textwidth}}     xxxxx &amp; xxxxx &amp; xxx &amp; xxxxx\\     \end{longtable} Storage for Eldritch Horror Is there an optimal strategy for storing Eldritch Horror cards and tokens so that game play is facilitated.   I am not looking for answers that including "zip bags" and other things to keep the game element safer while is storage. Although, a strategy that works well for both cases will clearly be superior to one that only works for game play.  I am not limiting this to commercial solutions. I am quiet happy to build your custom made solution if you release the specification/plans of course!  Although, it it requires a 3D printer, more power to you.