A tutorial shows cp -r   but   only shows -R.
cp -r is meant to copy files recursively, and cp -R for copying directories recursively. But I've checked, and both appear to copy both files and directories, the same thing. So, what's the difference actually?
How to resolve the "GPT detected. Please create a BIOS-Boot partition" error when using boot-repair? After installing Ubuntu, Windows didn't boot so I installed boot repair to fix this problem. But I am getting the message displayed below.  I tried to make a new partition with unformatted file system but still receiving the same message.  How do I fix it? This is a  about DNS glue records.   What exactly (but briefly) is a DNS glue record?  Why are they needed and how do they work? Which piece of equipment is holding me back? I am primarily an amateur photographer but I do take small jobs from time to time.  I'm looking to upgrade my equipment but I'm not sure if I should be spending money on my body, glass, or both.  I have two common issues that I'd like to improve.   I shoot a lot at ice rinks and find that even in servo mode I get a lot of shots that are slightly out of focus.  I try to keep the AF target on face masks but many shots will come out focused an inch or two off (ears, hands, etc).  I'm shooting F/1.8-F/2.8 to get action stopping shutter speeds so you can really tell when the focus is even a hair off.  I don't know if this is a limitation of my camera, lens, or the human operator. Most of my paid work is indoors shooting candids where a flash is inappropriate.  I feel like I need to use a higher F-number to get more subject in focus but I usually can't do it without upping to ISO 3200 unless I'm using a flash.  By the time I clean up the high ISO noise in Camera Raw I end up with an image lacking detail.  So far this hasn't been a big problem because the photos are typically used in magazine prints only an inch or two wide but it's still driving me nuts.   Here is the equipment currently in my bag:   Canon Rebel T2i Canon EF-S 18-55mm f/3.5-5.6 II (no IS)   Collecting dust, came with my old Rebel XTi.  Canon EF-S 18-135mm f/3.5-5.6 IS   Purchased with my T2i.  This is my workhorse lens but I'm disappointed with the soft images it produces at higher focal lengths.  Stopping down makes the images acceptable but that's not always an option.  My eyes want more contrast and color but considering how inexpensive this lens is I can't really complain.  Canon EF 70-300mm f/4-5.6 IS USM   This was purchased with an older camera and doesn't get used much anymore.  The images are too soft beyond 200mm and the AF seems sluggish.  Canon EF 50mm f/1.4 USM   I am extremely happy with the images I get from this lens.  I use it indoors all the time and also paired with extension tubes for some macro work.  Some of my best ice hockey images have been from this lens even though I didn't have sports in mind for this lens.    My initial plan was to upgrade to a 60D or 7D body but after doing some reading it occurred to me that I might invest in better glass first.  I'm unsure of what will help improve focusing, image quality, high ISO shooting, etc.  Maybe it's a new camera, new glass, photography lessons, or a little of everything?  I'm looking to keep my next round of purchases under $3,000 and am willing to trade in some of my used equipment to offset costs.  Would anyone care to make a recommendation?  I'm looking at the EOS 60D and 7D bodies.  Not sure if the 7D is overkill for my needs.  I'm also looking at the EF 24-70mm f/2.8L USM lens to be my new workhorse but I'm concerned that it may not be wide enough on an APS-C body and the lack of IS might be an issue.  There's also the EF 70-200mm f/2.8L IS II USM but I'm thinking it wouldn't be wise to spend all my budget on that lens right now (or maybe not?). Helical motion of charged particle in external magnetic field Why use the Conjure Minor Elemental spell when its results are so unpredictable? The  spell states:  You summon elementals that appear in unoccupied spaces that you can see within range. You choose one the following options for what appears:  One elemental of challenge rating 2 or lower Two elementals of challenge rating 1 or lower Four elementals of challenge rating 1/2 or lower Eight elementals of challenge rating 1/4 or lower.   It seems like the only two things a player can select are the maximum CR of the elemental conjured, and, arguably, the location its summoned in. I am confused as to why you would want to use this spell given that its results are so unpredictable. Why would a wizard cast a spell that's essentially an open invitation to whatever elemental from a list decides to show up? You can't strategize around the spell very much because, as written, you don't choose what gets summoned, and you can easily end up with something you weren't counting on. It won't be useless, but why would you cast a spell that has such an unpredictable result? It's like the difference between the chromatic orb and chaotic bolt - if the chaotic bolt didnt have the chance to bounce. You'd never pick a random damage type over a damage type of choice. Why would you choose a spell that might do something you want over something that does exactly what you intend it to do? What are the situations in which you would use this spell that wouldn't be better solved by a spell of equal or lower level that has more predictable results? How do I test a nonlinear association? For plot 1, I can test the association between x and y by doing a simple correlation.   For plot 2, where the relationship is nonlinear yet there is a clear relation between x and y, how can I test the association and label its nature? Prove that $\operatorname{trace}(A) = 0$ if and only if $A^2 = 0$. Idiomatic batch processing of text in Emacs? Exclude a view from master layout? At work we are being asked to create XML files to pass data to another offline application that will then create a second XML file to pass back in order to update some of our data. During the process we have been discussing with the team of the other application about the structure of the XML file.   The sample I came up with is essentially something like:  &lt;INVENTORY&gt;    &lt;ITEM serialNumber="something" location="something" barcode="something"&gt;       &lt;TYPE modelNumber="something" vendor="something"/&gt;     &lt;/ITEM&gt; &lt;/INVENTORY&gt;   The other team said that this was not industry standard and that attributes should only be used for meta data. They suggested:  &lt;INVENTORY&gt;    &lt;ITEM&gt;       &lt;SERIALNUMBER&gt;something&lt;/SERIALNUMBER&gt;       &lt;LOCATION&gt;something&lt;/LOCATION&gt;       &lt;BARCODE&gt;something&lt;/BARCODE&gt;       &lt;TYPE&gt;          &lt;MODELNUMBER&gt;something&lt;/MODELNUMBER&gt;          &lt;VENDOR&gt;something&lt;/VENDOR&gt;       &lt;/TYPE&gt;    &lt;/ITEM&gt; &lt;/INVENTORY&gt;   The reason I suggested the first is that the size of the file created is much smaller. There will be roughly 80000 items that will be in the file during transfer. Their suggestion in reality turns out to be three times larger than the one I suggested. I searched for the mysterious "Industry Standard" that was mentioned, but the closest I could find was that XML attributes should only be used for meta data, but said the debate was about what was actually meta data.  After the long winded explanation (sorry) how do you determine what is meta data, and when designing the structure of an XML document how should you decide when to use an attribute or an element? How do Prestige Classes that advance spellcasting interact with racial spellcasting ability? iOS crash log catch, debug info.. Catch and send via email to the Dev team Up my street and down the lane Possible Duplicate:          Except where there is obvious difference in elevation e.g. on a sloping road, how do native speakers decide whether to use up or down in phrases like up the road when referring to a location along the same road? Output of which command used for input to cd I would like to take the output of a which command, and cd to the parent directory. For example, say I have the following:  which someprogram   With output:  /home/me/somedirectory/someprogram   And I would like to cd to the directory that someprogram lives in:  cd /home/me/somedirectory   I'd like to accomplish this in one line. What is the most elegant, tricky, short way to do this? Mirror changes to side of cube across all six sides Layers with same coordinates not lining up I have a project where I have a few layers (State of Texas, cities, roads, etc.). They are all resaved and projected to NAD83 / UTM zone 14N EPSG: 26914. The project CRS is also NAD83 / UTM zone 14N EPSG: 26914 and on the fly projection is enabled. I added a text delimited file and cannot get them to line up. I checked the attribute table of the delimited file and the coordinates are correct. I cross-checked this with a point close to where a few of the points from the delimited file are and they are very close so in theory they should be lining up. I tried to save the delimited file and save it with the same projection and add the shp file back in and that did not work. Anyone have any ideas? I can't think of anything else to try. What do wizard children do before attending Hogwarts? Most of the wand-carriers that come from a non-Muggle family seem fairly uneducated when it comes to interacting with Muggles.  This implies that they don't go to any type of Muggle school before entering into their education at Hogwarts (or whichever Wizarding school they go to), or else they would at least understand some Muggle culture.  What do children from magical families do before going to Hogwarts if they don't go to a traditional school?  Is there any evidence that they're homeschooled? Please Join Us in Welcoming Our New Meta Stack Exchange Moderators! I am from a physics background and my mathematics is not very good, so pardon my insolence with the question.  Editing based on the comments : We know that $\pi$ in decimal (i.e. base 10) is transcendental. Is it possible to have a radix base in which $\pi$ can be rational in that base ?  PS : My question is in general for any transcendental number. How do I automatically remap buttons on my mouse at startup?