My "very low quality" flag of  has been declined, with a note that     The correct procedure here is to comment, down-vote or even edit.   I don't think there is much to comment on an answer consisting of a single word, hyperlinked to the correct page. What could my comment possibly say? "Please embed your link into a better answer"?  Downvoting this answer would be inappropriate, too, because the link leads you to the correct page.  Finally, editing a single-word answer is very much like making a stone soup - it is the same as writing a brand-new answer.  Should there be a rule that all answers consisting of a single link without meaningful explanation be considered very low quality?
Related:  (not a dupe, that's a feature request and was closed as a dupe of another one)        (old) post does indeed say that Link-only answers can be flagged as NAA, but there are a lot of posts like  which define Not An Answer is a way that it doesn't apply to link-only answers.  Can we get some up-to-date consensus on this? That link only answers are not allowed is .
I'm looking for a class in java that has key-value association, but without using hashes.  Here is what I'm currently doing:   Add values to a Hashtable. Get an iterator for the Hashtable.entrySet(). Iterate through all values and:   Get a Map.Entry for the iterator. Create an object of type Module (a custom class) based on the value. Add the class to a JPanel.  Show the panel.   The problem with this is that I do not have control over the order that I get the values back, so I cannot display the values in the a given order (without hard-coding the order).  I would use an ArrayList or Vector for this, but later in the code I need to grab the Module object for a given Key, which I can't do with an ArrayList or Vector.  Does anyone know of a free/open-source Java class that will do this, or a way to get values out of a Hashtable based on when they were added?  Thanks! What are the rules for calling the base class constructor? Evaluation of $$\sin \frac{\pi}{7}\cdot \sin \frac{2\pi}{7}\cdot \sin \frac{3\pi}{7} = $$   $\bf{My\; Try::}$ I have solved Using Direct formula::  $$\sin \frac{\pi}{n}\cdot \sin \frac{2\pi}{n}\cdot......\sin \frac{(n-1)\pi}{n} = \frac{n}{2^{n-1}}$$  Now Put $n=7\;,$ We get   $$\sin \frac{\pi}{7}\cdot \sin \frac{2\pi}{7}\cdot \sin \frac{3\pi}{7}\cdot \sin \frac{4\pi}{7}\cdot \sin \frac{5\pi}{7}\cdot \sin \frac{6\pi}{7}=\frac{7}{2^{7-1}}$$  So $$\sin \frac{\pi}{7}\cdot \sin \frac{2\pi}{7}\cdot \sin \frac{3\pi}{7} =\frac{\sqrt{7}}{8}$$  Now my question is how can we solve it without using Direct Formula, Help me  Thanks Is a sub-shell the same thing as a child-shell There are this two names: a subshell and a child-shell.  Yes, a child process will be started by any of this:  sh -c 'echo "Hello"' ( echo "hello" ) echo "$(echo "hello") echo "hello" | cat   Are all equivalent and share the same name? Do all share the same properties?    POSIX :     A shell execution environment consists of ....   But the last paragraph of above link has this:     A subshell environment shall be created as a duplicate of the shell environment, except that signal traps that are not being ignored shall be set to the default action.    And specially:     Command substitution, commands that are grouped with parentheses, and asynchronous lists shall be executed in a subshell environment. Additionally, each command of a multi-command pipeline is in a subshell environment; ....   The sh -c 'echo "Hello"' is not included there, should that be called a subshell also? Invalid Data Source when importing geojson to QGIS Im trying to import geojson, I add data, select protocol and use the uri  QGIS says "Invalid Data Source:  is not a valid or recognized data source"  I've followed the tutorial here  but I cant get the data to come in, any ideas? I'm using QGIS version 2.18.13 I have a 1TB FAILING hard drive, a brand new 1 TB hard drive, a bootable ubuntu usb, and a working computer.  All I need is a step by step process of how to safely clone as much data as possible from one to the other. NOTE: THE DRIVE IS FAILING.  I know I need to enable multiverse and then install and use ddrescue to complete the task. But everywhere I look online, I can't get a straight path to the task. I know that this can be all done within the terminal and that's what I seek.  How can I do this? What color codes can I use in my PS1 prompt? I used several colors in my PS1 prompt such as   \033]01;31\] # pink \033]00m\]   # white \033]01;36\] # bold green \033]02;36\] # green \033]01;34\] # blue \033]01;33\] # bold yellow   Where can I find a list of the color codes I can use?  I looked at  but it didn't answer my question about a list of the actual codes.  It would be nice if there was a more readable form also.  See also Windows 8 removes Grub as default boot manager I have a Sony VAIO S series with Windows 8 preinstalled, and I installed Ubuntu 12.10 on a new partition. When the PC boots Grub is display, and I can choose between Windows 8 (didn't worked at the beginning, had to change Grub settings) and Ubuntu 12.10. When I select Ubuntu 12.10 everything is OK, but when I use Windows 8, and I restart Grub isn't displayed anymore (Windows 8 boots immediately).  I booted a Ubuntu 12.10 LiveUSB, used efibootmgr, and found out that Windows 8 (each time it boots) changes EFI default bootloader from Grub to Windows Boot Manager.  How do I change this in Windows 8? I read something about bcdedit, but it does not work or I don't know how to use it... How do I minimize total cost of separate flights to the same destination plus optionally accommodation? My girlfriend and I are currently living in different countries, and meet occasionally for a few days every month or so. We don't really care all that much where we are going, as long as we don't need a visa (we're both in EU), just so we are at the same place and time for a couple of days.   In short:     I'm flying from airport AAA, she's flying from airport BBB, we need to find an airport XXX (not a euphemism!) which is cheapest to fly to overall.   Bonus task: Flights are first and foremost, and we could live with a somewhat more expensive accommodation as long as we can get in and out easily. Since the accommodation cost is comparable to flight cost for such a short stay, we'd like to have some sort of rough idea what we're going to pay for a certain type of accommodation, for example three-star hotel. Thesis chapter headings, any suggestions? I've found a thesis with really beautiful chapter headings that I would like to use. What package am I going to need and how would I go about creating a heading that looks like the one below. Also, if you have or know of any nice headings do please share! Two list-boxes, side by side, one with available items, the other with selected items, with arrows in between to move items back and forth. Show that $\left | \sin a - \sin b \right | \leq \left | a-b \right |$ Fastest, surest way to erase a hard drive? Fantasy book series with non-human races and labyrinth Why does Linux require that a user be root/using sudo/specifically authorized per mount in order to mount something? It seems like the decision as to whether to allow a user to mount something should be based on their access rights to the source volume/network share and to the mount point. A couple of uses for non-root mounting are mounting file-system images to a user owned direction and mounting a network share to a user owned directory. It seems like if the user has control over both sides of the mount equation everything should be cool.  Clarification of access restriction:  I feel I should be able to mount anything that the user otherwise would have access to to a mount-point that the user is the owner of.  For instance, on my computer /dev/sda1 is owned by user root and group disk with permissions brw-rw----. Therefore non-root users can't mess with /dev/sda1 and clearly mount shouldn't allow them to mount it. However if the user owns /home/my_user/my_imagefile.img and mount point /home/my_user/my_image/ why shouldn't they be able to mount that image file on that mount point with:  mount /home/my_user/my_imagefile.img /home/my_user/my_image/ -o loop   As kormac pointed out there is a suid problem. So some restrictions would have to be added to prevent suid from being a problem as well as potentially some other issues. Perhaps one way to do this would be to make the OS treat all files as belonging to the user that did the mounting. However for simple read/write/execute, I don't see why this would be a problem.  Use case:  I have an account in a lab where my home space is restricted to 8GB. This is tiny and very very annoying. I would like to mount an nfs volume from my personal server to essentially increase the amount of room that I have. However, because Linux does not allow such things I'm stuck with scp'ing files back and forth to stay under the 8GB limit. Proving a three variables inequality How to return multiple objects from a Java method? Orthographic scale of camera in Blender could somebody explain how orthographic scale is calculated in Blender? I am trying to match an orthographic view that I get from another software with that of Blender, but I am not able. Camera gets in the correct position but the zoom level is wrong.  Thanks, byte I suspected that installing xfce4 cause some issues in Ubuntu so I removed them using apt-get remove xfce4 xfce4-goodeis.  But when I ran 'dpkg -l' I still can see some libraries and packages for xfce4:  $ dpkg -l | grep -i xfce rc  libexo-1-0:amd64                              0.10.2-2                                 amd64        Library with extensions for Xfce rc  libgarcon-1-0                                 0.2.1-1                                  amd64        freedesktop.org compliant menu implementation for Xfce rc  libxfce4ui-1-0                                4.11.0-0ubuntu1~ppa0.13.10.1             amd64        widget library for Xfce - Gtk+2 variant rc  libxfce4ui-common                             4.11.0-0ubuntu1~ppa0.13.10.1             all          common files for libxfce4ui rc  libxfce4util6                                 4.10.1-1                                 amd64        Utility functions library for Xfce4 rc  libxfcegui4-4                                 4.10.0-2                                 amd64        Basic GUI C functions for Xfce4 rc  libxfconf-0-2                                 4.10.0-2                                 amd64        Client library for Xfce4 configure interface rc  mousepad                                      0.3.0-2                                  amd64        simple Xfce oriented text editor rc  thunar                                        1.6.3-1ubuntu1                           amd64        File Manager for Xfce rc  xfce4-appfinder                               4.10.1-1                                 amd64        Application finder for the Xfce4 Desktop Environment rc  xfce4-clipman                                 2:1.2.3-2ubuntu1                         amd64        clipboard history utility rc  xfce4-mixer                                   1:4.10.0-1ubuntu2                        amd64        Xfce mixer application rc  xfce4-notes                                   1.7.7-3ubuntu2                           amd64        Notes application for the Xfce4 desktop rc  xfce4-panel                                   4.10.1-1ubuntu1                          amd64        panel for Xfce4 desktop environment rc  xfce4-power-manager                           1.2.0-2ubuntu1                           amd64        power manager for Xfce desktop rc  xfce4-session                                 4.10.1-1ubuntu1                          amd64        Xfce4 Session Manager rc  xfce4-settings                                4.11.1-0ubuntu1~ppa0.13.10.1             amd64        graphical application for managing Xfce settings rc  xfce4-terminal                                0.6.2-3ubuntu1.1                         amd64        Xfce terminal emulator rc  xfce4-volumed                                 0.2.0-0ubuntu1                           amd64        volume keys daemon rc  xfdesktop4                                    4.11.2-0ubuntu1~ppa0.13.10.1             amd64        xfce desktop background, icons and root menu manager rc  xfwm4                                         4.11.1-0ubuntu1~ppa0.13.10.1             amd64        window manager of the Xfce project   I copy-pasted all these packages\libraries to form an apt-get remove command to remove all of these dependencies, and the command ran normally, but running dpkg -l | grep -i xfce showed these dependencies again !  Why are these dependencies still installed ? import Excel sheets by name