Pass environment variables' values to a program?
pass 1 environment variable using sudo
How to find $ f(x)$ if $f(1-f(x))=x$ for all $x$ $\in \mathbb{R}$ How can I determine $ f(x)$ if $f(1-f(x))=x$ for all real $x$?  I have already recognized one problem caused from this: it  follows that $ f(f(x))=1-x $, which is discontinuous. So how can I construct a function $f(x)$?  Best regards and thanks, John Persistent Dummy Output Even when I start a brand new file in Blender, I only get four video output file options: AVI raw, AVI JPEG, Frame Server, FFMpeg Video.  I am running version 2.78.5 (I'm using the beta so that I can use denoising.  How can I get access to all the other video outputs other people have? Like this: Unity Performance: How many Materials per Object? After enabling hibernate grub menu appears on start-up with 30s timeout My system is not dual boot just single OS UBUNTU 16.04. Prior to making the following changes, the Grub screen would not appear at start-up (OK).  After following these steps from  to enable hibernate in the system menu:   Open terminal and enter;   sudo nano /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla  add the lines into the empty file;  [Re-enable hibernate by default in upower] Identity=unix-user:* Action=org.freedesktop.upower.hibernate ResultActive=yes  [Re-enable hibernate by default in logind] Identity=unix-user:* Action=org.freedesktop.login1.hibernate;org.freedesktop.login1.handle-hibernate-key;org.freedesktop.login1;org.freedesktop.login1.hibernate-multiple-sessions;org.freedesktop.login1.hibernate-ignore-inhibit ResultActive=yes  ^X then Y to save (a filename was suggested and I accepted without taking note).  Reboot for the changes to take effect.   hibernate now works and appears in the menu (OK) but whenever I reboot I now get a Grub menu at start up with a full 30 second timeout (NOK). I tried playing around with the Grub menu timeout settings but still get the full 30 sec timeout.  How do I stop the Grub menu from appearing and reduce my boot time to what it was before I made these changes.   Current Grub settings;   GRUB_DEFAULT="0" GRUB_HIDDEN_TIMEOUT="0" GRUB_HIDDEN_TIMEOUT_QUIET="true" GRUB_TIMEOUT="1" GRUB_DISTRIBUTOR="`lsb_release -i -s 2&gt; /dev/null || echo Debian`" GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" Recently I found a claim saying that  $$  \int_0^\infty \left( \frac{\sin ax}{x}\right)\left( \frac{\sin bx}{x}\right) \mathrm{d}x= \pi \min(a,b)/2  $$ from what I can see this seems to be true. I already know that $\int_{0}^\infty \operatorname{sinc}xy\,\mathrm{d}y = \pi/2$, and so independant of $y$. My suspicion is that this is closely related to the integral above.   Can someone give me some suggestions for evaluating the integral above? Also are there any generalizations for the integral? Eg $$ \int_{0}^{\infty} \left( \prod_{k=1}^N \frac{\sin (a_k \cdot x)}{x} \right) \,\mathrm{d}x $$ Where $a_k, \cdots, a_N$ are arbitrary positive constants. It seems related to the , but there are some subtle differences. Get all non-unique values (i.e.: duplicate/more than one occurrence) in an array I am wondering if there is anything in Marvel comic book canon or in the MCU that says that the Infinity Gauntlet has the power to make someone fall in love with the person wearing the Infinity Gauntlet, or that the wearer of the Infinity Gauntlet can use the Infinity Gauntlet to make two strangers fall in love with each other? Perhaps the combined power of the Mind Stone and the Soul Stone would make two people fall in love. SELECT * EXCEPT Is there any RDBMS that implements something like SELECT * EXCEPT?  What I'm after is getting all of the fields except a specific TEXT/BLOB field, and I'd like to just select everything else.  Almost daily I complain to my coworkers that someone should implement this...  It's terribly annoying that it doesn't exist.  Edit: I understand everyone's concern for SELECT *.  I know the risks associated with SELECT *.  However, this, at least in my situation, would not be used for any Production level code, or even Development level code; strictly for debugging, when I need to see all of the values easily.  As I've stated in some of the comments, where I work is strictly a commandline shop, doing everything over ssh.  This makes it difficult to use any gui tools (external connections to the database aren't allowed), etc etc.  Thanks for the suggestions though. $\int f=0$ implies $f=0$ almost everywhere Let $f$ be nonnegative and measurable. Show that $\int f =0$ implies $f=0$ almost everywhere (except possibly on a set of measure zero).  My thoughts. Take a set E with $m(E) \neq 0$. Suppose $f \neq 0$ on E. That means $\int_E f \neq 0$. Since $f$ is nonnegative this implies $\int f &gt;0$. That contradicts the given information, so $f$ must be 0 almost everywhere. What happens if you do sudo passwd without specifying a user? I wanted to change my own password (as an admin) so I did the following command:  sudo passwd   and then it prompted for a password but when I tryed to relog, my password was not changed. I'm now wondering what password did I changed since it did prompted me to enter a password but I'm not sure what password did it changed exactly.  I know that if I do sudo passwd &lt;MY_USER&gt; it works, I'm just wondering without a user what happens.  Thank you Using Laptop Screen as a monitor I know that this machine does not work, via thermodynamics. I am asking for an analysis in terms of mechanics and magnetism.  Anyway, so here is the machine:   (source: )    The magnet (the red ball) pull the ball up the ramp, and then it drops the ball through the hole, which then rolls down, and go ups the ramp again. Thermodynamics shows that this can not work.  From a mechanics and magnetism perspective, what happens when you do this, and why can't it happen?  I have a source saying that it would work if it were frictionless and we didn't try to extract energy from it (), so in a certain sense, it is very close to possible (they didn't provide a full analysis though.)  Another Image: I'll be generous and say it might be reasonable to assume that nature would tend to minimize, or maybe even maximize, the integral over time of $T-V$.  Okay, fine.  You write down the action functional, require that it be a minimum (or maximum), and arrive at the Euler-Lagrange equations.  Great.  But now you want these Euler-Lagrange equations to not just be derivable from the Principle of Least Action, but you want it to be equivalent to the Principle of Least Action.  After thinking about it for awhile, you realize that this implies that the Principle of Least Action isn't really the Principle of Least Action at all:  it's the "Principle of Stationary Action".  Maybe this is just me, but as generous as I may be, I will not grant you that it is "natural" to assume that nature tends to choose the path that is stationary point of the action functional.  Not to mention, it isn't even obvious that there is such a path, or if there is one, that it is unique.  But the problems don't stop there.  Even if you grant the "Principle of Stationary Action" as fundamentally and universally true, you realize that not all the equations of motions that you would like to have are derivable from this if you restrict yourself to a Lagrangian of the form $T-V$.  As far as I can tell, from here it's a matter of playing around until you get a Lagrangian that produces the equations of motion you want.  From my (perhaps naive point of view), there is nothing at all particularly natural (although I will admit, it is quite useful) about the formulation of classical mechanics this way.  Of course, this wouldn't be such a big deal if these classical ideas stayed with the classical physics, but these ideas are absolutely fundamental to how we think about things as modern as quantum field theory.  Could someone please convince me that there is something natural about the choice of the Lagrangian formulation of classical mechanics (I don't mean in comparison with the Hamiltonian formulation; I mean period), and in fact, that it is so natural that we would not even dare abandon these ideas? How do I parse command line arguments in Java? Rotating image / marker image on Google map V3 Why does $(x \to a) ≠ (x = a)$ , But $f(x \to a) = f(x = a)$ How to relate areas of circle, square, rectangle and triangle if they have same perimeter?? I was given a question which was like:     Suppose that a circle, square, rectangle and triangle have same perimeter. How area their areas related??   My work:  I broke the question in parts and tried to prove it seperately:  STEP $1$. Suppose the given perimeter is $P$.So the radius of circle will be ${r=P/2\pi}$.  And hence area of the circle will be:   ${P^2/4\pi}$.  Side of square will be $P/4$ and hence area of square will be $P^2/16$.   It is obvious that ${P^2/4\pi}$  >  $P^2/16$.   So Area of circle is more than area of square.  STEP $2$: Whether by using $AM&gt;GM$ inequality or by using a bit of differentiation, we can get that product off two quantities is maximum when they are equal.  So, Area of square is more than Area of rectangle.  Here, the hardest part come (at least for me). I can't relate the area of triangle to any of Circle, Square or Rectangle. It would have been easy if the triangle was Equilateral, Right angle but the question is talking about a general triangle.  However, when I considered the situation with different examples (Assuming the perimeter and calculating the area, I got the relation:  Circle > Square > Rectangle > Triangle.  I shall be highly thankful if you guys can establish the relation in purely mathematical way.  EDIT: This question does not ask that whether circle have the largest area among all 2-D figures or not. The OP just want to relate the areas of Circle, Square, Rectangle, Triangle in a pure mathematical way. I'm runing 15.04 on a dell xps 13 bluetooth recognises devices when i  try to add them but won't let me connect to them Here is the results from my terminal.  ~ $ uname -a; lspci -nnk | grep -iA2 net; lsusb; dmesg | grep -i bluetooth; dmesg | grep -i firmware; lsmod | grep bluetooth  Linux aaron-XPS-13 3.19.0-15-generic #15-Ubuntu SMP Thu Apr 16 23:32:37 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux 02:00.0 Network controller [0280]: Broadcom Corporation BCM4352 802.11ac Wireless Network Adapter [14e4:43b1] (rev 03)     Subsystem: Dell Device [1028:0019]     Kernel driver in use: wl Bus 003 Device 002: ID 8087:8001 Intel Corp.  Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 0bda:5682 Realtek Semiconductor Corp.  Bus 001 Device 002: ID 0a5c:216f Broadcom Corp.  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub [    8.164048] Bluetooth: Core ver 2.20 [    8.164065] Bluetooth: HCI device and connection manager initialized [    8.164069] Bluetooth: HCI socket layer initialized [    8.164073] Bluetooth: L2CAP socket layer initialized [    8.164079] Bluetooth: SCO socket layer initialized [    8.353160] bluetooth hci0: Direct firmware load for brcm/BCM20702A0-0a5c-216f.hcd failed with error -2 [    8.353166] Bluetooth: hci0: BCM: patch brcm/BCM20702A0-0a5c-216f.hcd not found [   20.289452] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [   20.289455] Bluetooth: BNEP filters: protocol multicast [   20.289459] Bluetooth: BNEP socket layer initialized [   20.310897] Bluetooth: RFCOMM TTY layer initialized [   20.310907] Bluetooth: RFCOMM socket layer initialized [   20.310912] Bluetooth: RFCOMM ver 1.11 [  886.399085] Bluetooth: hci0 urb ffff8800d8c15e40 failed to resubmit (2) [  895.471190] Bluetooth: hci0: BCM: patching hci_ver=06 hci_rev=1000 lmp_ver=06 lmp_subver=220e [  896.113983] Bluetooth: hci0: BCM: firmware hci_ver=06 hci_rev=1624 lmp_ver=06 lmp_subver=220e [    8.353160] bluetooth hci0: Direct firmware load for brcm/BCM20702A0-0a5c-216f.hcd failed with error -2 [  896.113983] Bluetooth: hci0: BCM: firmware hci_ver=06 hci_rev=1624 lmp_ver=06 lmp_subver=220e bluetooth             491520  22 bnep,btusb,rfcomm ~ $ How can I make a special file that executes code when read from Most files on a Linux system are normal files, i.e. they are saved on disk and reading from them just reads from a specified chunk of memory on the disk.  How can I make something that behaves like a file in terms of being able to read from it as one would a normal file, but is actually returning programmatically generated data instead?  As a concrete example, a file that downloads the current google.com and returns it, such that cat ~/myspecialfile would output the contents of google.com to stdout?