Ubuntu 14 came with perl v5.18.2, but I would like to test my program with perl v5.22.0 which is installed through perlbrew and then perlbrew switch perl-5.22.0 to use the version I want.  After switch to perl v5.22.0, I have tried to test my program with sudo but why it is executed in default perl v5.18.2?      perl -v: result         sudo perl -v : result
This is the PATH variable without sudo:  $ echo 'echo $PATH' | sh  /opt/local/ruby/bin:/usr/bin:/bin   This is the PATH variable with sudo:  $ echo 'echo $PATH' | sudo sh /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin   As far as I can tell, sudo is supposed to leave PATH untouched. What's going on? How do I change this? (This is on Ubuntu 8.04).  UPDATE: as far as I can see, none of the scripts started as root change PATH in any way.  From man sudo:      To prevent command spoofing, sudo   checks ``.'' and ``'' (both denoting   current directory) last when searching   for a command in the user's PATH (if   one or both are in the PATH). Note,   however, that the actual PATH   environment variable is not modified   and is passed unchanged to the program   that sudo executes.
Partial Sums of Geometric Series Is there a guideline about when to end expressions with semicolons? Find the value of $g'(0)$. Let $f: \mathbb{R} \rightarrow \mathbb{R}$ be a continuous function with $f(1) = 5$ and $f(3) = 11$. If $g(x) = \int_1^3 f(x+t)dt$ then find $g'(0).$   Please explain your answer. How do I embed an image from the web into a Trello card comment or description? So far I have been successful embedding Youtube videos into Trello card comments; simply by including the URL in the comment Trello picks it up and renders an embedded Youtube thumbnail.   What I would like to do is the same thing, but with a simple PNG image. I don't want to upload the image as it is a Balsamiq mockup permalink which will get updated periodically, and I want the latest version to be displayed on the Trello card.   However, pasting the image URL into the Trello card has no effect.  Am I missing somthing? Wikipedia introduces the vector product for two vectors $\vec a$ and  $\vec b$ as $$ \vec a \times\vec b=(\| \vec a\| \|\vec b\|\sin\Theta)\vec n $$ It then mentions that $\vec n$ is the vector normal to the plane made by $\vec a$ and  $\vec b$, implying that $\vec a$ and  $\vec b$ are 3D vectors. Wikipedia mentions something about a 7D cross product, but I'm not going to pretend I understand that.  My idea, which remains unconfirmed with any source, is that a cross product can be thought of a vector which is orthogonal to all vectors which you are crossing.  If, and that's a big IF, this is right over all dimensions, we know that for a set of $n-1$ $n$-dimensional vectors, there exists a vector which is orthogonal to all of them.  The magnitude would have something to do with the area/volume/hypervolume/etc. made by the vectors we are crossing.  Am I right to guess that this multidimensional aspect of cross vectors exists or is that last part utter rubbish? This error message is being presented, any suggestions?     Allowed memory size of 33554432 bytes exhausted (tried to allocate   43148176 bytes) in php Is Force lightning from the feet plausible? In all the canons of Star Wars, there has not been one instance of a Force-user projecting Force lightning from their feet. Why? Is it implausible? Can you help me with my capacity planning? Dictionary application needs to download dictionary "Apple Dictionary" before use I'm repeatedly being asked to download the "Apple Dictionary" when I open the dictionary application.     Dictionary application needs to download dictionary "Apple Dictionary" before use.   This doesn't happen every time I open it. I haven't pinned down specific usage cases where this message appears, but I think it may be every time after I reboot my computer.  Is there anyway for the Dictionary application to remember that I have "Apple Dictionary" permanently? This has only started happening after I upgraded from OS X Mountain Lion to macOS Sierra. . It is a mathematical expression/sequence/set of numbers with the arrow exactly under any one of the numbers (with or without n= 0). How to do it in latex? Any of the up arrow types (single line or double line) shown in the figure is okay. Is there any easy way to open the document library files in a new window or popup depending on the file types?  e.g. PDF - In Adobe reader (currently opens in IE)  Image file (currently opens in IE) Sci-Fi book female fighter pilot All I remember about the book is that the protagonist was a human female fighter pilot, she has short hair, not sure if it was blond or auburn and she was involved in making peace with the alien race.  The alien race was invading Earth, but because of her they stopped, surrendered and because of her helped Earth improve its technology. I remember that she melded with something and was starting to sort of think like them and lose a bit of her humanity.  It was set in the not too distant future. I believe I read it in the 90s. Why is my mesh inversed when Imported to Unity? So I modeled this sword and all the parts were separate meshes. I used a mirror modifier when I was modeling and then I applied the modifier when I was done to make the parts into solid meshes. Put a UV map on everything and it all looked good in Blender.  Then I put it into Unity and I got what you see in the picture. Part of the sword is inversed. Oddly, the inversed part actually maintains the proper silhouette. It maintains the correct shape, but then is shaded like the front half is missing.  Does anyone have an idea of what's going on and how to fix it?  Thanks, James How to Create a Vinyl Plastic Toy Shader? How can I make one of the vinyl toy plastic material like this?    Video: amsalpha-like bibtex style with manual labels I use my computer for scientific programming. It has a healthy 8GB of RAM and 12GB of swap space. Often, as my problems have gotten larger, I exceed all of the available RAM. Rather than crashing (which would be preferred), it seems Ubuntu starts loading everything into swap, including Unity and any open terminals. If I don't catch a run-away program in time, there is nothing I can do but wait - it takes 4-5 minutes to switch to a command prompt eg. Ctrl-Alt-F2 where I can kill the offending process.  Since my own stupidity is out of scope of this forum, how can I prevent Ubuntu from crashing via thrashing when I use up all of the available memory from a single offending program?  At-home experiment*!  Open a terminal, launch python and if you have numpy installed try this:  &gt;&gt;&gt; import numpy &gt;&gt;&gt; [numpy.zeros((10**4, 10**4)) for _ in xrange(50)]   * Warning: may have adverse effects, monitor the process via iotop or top to kill it in time. If not, I'll see you after your reboot. How do I install a .tar.gz (or .tar.bz2) file? How do I prove that $ \displaystyle\lim_{n \to{+}\infty}{\sqrt[n]{n!}}$ is infinite? I made something like this:    I did this with the Ellipse Tool and the Line Tool.  Now the circle is accurate, but the lines inside are very inaccurate. Is there another tool that does the same thing but with a lot more accuracy? How to hide notification center button in Mountain Lion? I am using Mountain Lion.  The only advantage (for me) over the gesture is that Option + clicking the button enables/disables showing alerts and banners (toggles the switch in the notifications center).  Is there a way to hide the button in the status bar that opens notification center?