Temporary SIM card while visiting US
How can I find the cheapest prepaid SIM card for a given country?
I am developing a game with a Minecraft-like terrain made out of blocks. Since basic rendering and chunk loading is done now, I want to implement block selecting.  Therefore I need to find out what block the first person camera is facing. I already heard of unprojecting the whole scene but I decided against that because it sounds hacky and isn't accurate. Maybe I could somehow cast a ray in view direction but I do not know how to check the collision with a block in my voxel data. Of course this calculations must be done on the CPU since I need the results to perform game logic operations.  So how could I find out which block is in front of the camera? If it is preferable, how could I cast a ray and check collisions? Lets say that I have a directory with the following files (among others):  touch doc-mike.txt doc-jane.txt doc-susan.txt   I can do something in a script with those files using a construct like:  for fname in doc-*.txt; do     echo input: ${fname} done   But if I want to get the substring of the filename that matches the wildcard I have to jump through some ugly hoops:  for fname in doc-*.txt; do     wildcard=${fname#doc-}     wildcard=${wildcard%.txt}      echo input: ${fname} output: output-${wildcard}.results done   That works:  input: doc-jane.txt output: output-jane.results input: doc-mike.txt output: output-mike.results input: doc-susan.txt output: output-susan.results   but I feel like there has to be a better/easier way to get the substring that matches the "*" glob wildcard Why is the triangle inequality property important for metric spaces? There is a property in the axiomatization of metric space: $d(x,z)\le d(x,y)+d(y,z)$. I understand that property applies well when it come to the measure of distances among points. However, that property seems to be irrelevant in the definitions of continuity, open set and some other key concepts.  My topology book says that it is asserting "the transitivity of closeness", a vague term that loses me. So why is that property important? Why did the founders (if any) of topology consider it at the first place? And what if that property is missed? Add days to JavaScript Date One word/phrase to describe the reaction when you eat a very spicy-hot food I've read the discussion here about .  I've also read this one: .  But I did not find any word or phrase that describes the reaction someone has when eating a too spicy-hot food. You know, they tend to sweat, catch their breath, and even sometimes shed tears; due to the spiciness of the food.  So my questions:        What do you say to describe the reaction someone has when being excitedly "suffered" by a very spicy-hot food? In Indonesian, we would call it kepedasan.   What do you say when you get that thing [the answer to question 1] with you, other than the list I enclose below:                Oh, spicy!     My God, it's spicy-hot!                      Is that it? ImportError: no module named win32api I heard a lot about in-body image stabilization recently and I wonder how this technology works. I don't mean the mechanical part (I understand how the sensor moves along different axes to compensate), but the technique in principle:  When I take my 5D III and a lens like the 70-200 2.8 II IS USM with activated stabilization, the IS will constantly move one glas element within the lens in such a way that it directs the cone of light exactly onto the sensor, so that you can always use the full sensor area.  When the cone of light goes through an unstabilized lens and you need to move the sensor - how can it capture the same amount of light at all? The light enters the lens down a fixed axis right through the center of the lens. When the sensor currently moves down, for example, to compensate for a shake, I can't see how it then is still able to capture the full resolution? When a part of the sensor is below default/calm position, then there must be missing the same part on the opposite site?  There's only one way I could image IBIS to work without resolution reduction: if the sensor area was significantly bigger than the area exposed to light, so that there's still sensor available when it currently moves out of its initial position. But wouldn't this (partly) be the same as digital stabilization because the final image gets calculated from the full sensor area minus the not exposed area?  I really would like to understand this and it would be great if someone could "shed some light on this". Infinite Series $1+\frac12-\frac23+\frac14+\frac15-\frac26+\cdots$ Was given the following infinite sum in class as a question, while we were talking about Taylor series expansions of $\ln(1+x)$ and $\arctan(x)$: $$1+\frac12-\frac23+\frac14+\frac15-\frac26+\cdots$$  The question isn't homework or anything, just a thought tease. I tried for a long while but couldn't find anything remotely close. Thanks in advance for the help. My computer no longer boots Windows or the installed operating system. Instead, I may get this error:  PXE-E61: Media test failure, check cable -or- Check cable connection!  PXE-M0F: Exiting PXE ROM.   and/or one of the following messages or similar:  Operating System not found  No boot device available- No bootable devices--strike F1 to retry boot, F2 for setup utility  No bootable device -- insert boot disk and press any key  No Boot Device Found. Press any key to reboot the machine  Default Boot Device Missing or Boot Failed  Reboot and Select proper Boot device or Insert Boot Media in selected Boot device   What does this mean and what can I do?     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details. I have a live USB made with the standard Ubuntu disk image creator for 16.04 LTS. In the current state, I can boot to this disk, but it still requires the original USB to run properly at all times.  Attempting to pull the drive and use the system generates a large amount of I/O errors, further suggesting that the USB drive is actually needed for things not already loaded into RAM (For example, Firefox worked without the USB, but I used it once before already. apt, on the other hand, did not.)  Is there a way to copy the entire Ubuntu live disk to RAM, so I can remove the drive and free up a USB slot for other things? Intersection reports invalid geometries What are the differences between normal and classic difficulties? I can't seem to find a good list of info of all the changes that classic mode offers over normal other than that 'its much harder'.  Does any of the enemy AI improve in classic mode?  Do enemies have more health and do more damage?  Does the panic meter increase faster for countries? How do I create a decimal field in Access with Alter Table? Cannot access to (or find out) main Settings program Windows file copy dialog: Why is the estimation so... BAD? I know that the Windows copy dialog (in Windows&nbsp;XP) stores the copy in memory first, and it is still copying after the dialog closes, so the time is off, but why is the estimation of the time it will take to make a copy so inaccurate, even when memory copying has been disabled (in Vista and Windows&nbsp;7)? It seems so arbitrary! How does the whole copy procedure work, and why can't Windows estimate it correctly? only display df lines that have more fs usage than 80% root@SERVER ~$ df Filesystem  512-blocks  Free    %Used   Iused   %Iused  Mounted on /dev/YXCV   655360      365632  45% 6322    13% / /dev/ASDF   3801088     670648  83% 41759   32% /usr /dev/ASR    1048576     500496  53% 5555    9%  /var   How can I pipe the df command's output to only display lines that have more usage than 80%?  e.g.: it would only display:  /dev/ASDF   3801088     670648  83% 41759   32% /usr Executing user-supplied ruby code on a web server Blender saves a new file every time When I click save or hit Command + S what appears to be a new version of the document is created. So if I save 2 times, I get 2 documents, filename.blend1 and filename.blend2.  What exactly are these files and why is Blender creating them? Is Unit Testing worth the effort? I am working to integrate unit testing into the development process on the team I work on and there are some sceptics. What are some good ways to convince the sceptical developers on the team of the value of Unit Testing? In my specific case we would be adding Unit Tests as we add functionality or fixed bugs. Unfortunately our code base does not lend itself to easy testing. I've had my HTC Desire for a couple of months now and it is awesome! (A huge improvement to my previous phone... Nokia 3315)  Though recently, I've realised that the phone semi-freezes more and more often - ie. when swiping between homescreens it will either pause/freeze and I will have to re-swipe to get it to change screens. Or worse, it just won't respond to any further swipes and I have to lock the screen then unlock to get the phone back into action.  Got quite annoyed at this (was probably happening once or twice a day) so I thought it might help to turn it off and on again. So I did - not sure if it was a placebo effect but it seems to have helped a bit?  So given that this is my first smartphone, I was wondering if it is 'normal' to need to restart the phone every so often. If so, how often is 'normal'? If not, what can I do to diagnose/fix this problem?