So this is a part of my coursework A452 which states I need to research and ask forums if I don't know the question. I've tried to research this for hours on end and all I find is what the /bin directory does. I know what it does, it's very simple; it's a subdirectory of the root which contains executable files and commands. But how do I use an example to prove this using the terminal? Is there a command I could use to prove it? The full question listed in the coursework is below:  10C) What is the purpose of the bin directory? Use examples to explain this.   Can it please be detailed because the whole thing is worth 30% of my grade however this is the only question I'm stuck on. :((
What is the purpose of the bin directory? What are some examples?
Seems like a bug:  The user:   Edits a question Then, he decide to close it. Clicks on the Close button. The popup doesn't appear. Refreshes the page. Click on the close button. The popup appears.   After editing in the link appears a hash: #. But I don't think that this is the problem because if I add the hash without editing the close popup appears.  It's minor, but I think that is good to be reported and solved.  Edit: The close popup doesn't open after we click an edit has been made to this post; click to load. How to create svg symbols that have modifiable fill color, stroke color and stroke width? I want to create some svg symbols for Qgis using Inkscape, those symbols must have attributes as described in the question. For the last two days, I have been experimenting as instructed by  and mimicked some symbols came bundled with qgis that have desired attributes without any success.  Finally I experimented with the simplest form of symbol: I created an svg that contains only a circle in Inkscape and tried to modify it.  The original file () have this line:  &lt;path    sodipodi:type="arc"    style="fill:#ffffff;fill-opacity:1;stroke:#000000;stroke-width:1.01988637;stroke-miterlimit:4;stroke-opacity:1;stroke-dasharray:none"   I modified it into:  &lt;path    sodipodi:type="arc"    style="fill:param(fill) #ffffff;fill-opacity:1;stroke:param(outline) #000000;stroke-width:param(stroke-width) 1.01988637;stroke-miterlimit:4;stroke-opacity:1;stroke-dasharray:none"   Saved as  and selected it as point symbol, but Qgis couldn't change all three parameters at the same time.  What did I do wrong or should do differently?  My system: Qgis 1.8.0 on Ubuntu 12.04 64 bit, Inkscape 0.48, Gedit 3.4.1 text editor. How to resize partitions? The speed of light is the same in all inertial frames.  Does it change from a non-inertial frame to another? Can it be zero?  If it is not constant in non-inertial frames, is it still bounded from above? Show the existence of a certain subgroup of F2 Consider the atomic spectrum (absorption) of hydrogen.     The Bohr's model postulates that there are only certain fixed orbits allowed in the atom. An atom will only be excited to a higher orbit, if it is supplied with light that precisely matches the difference in energies between the two orbits.   But how precise does 'precisely' mean. Of course, if we need energy $E$ to excite the electron to a higher energy level, and I supply a photon with just $E/2$ I would expect nothing to happen (since the electron cannot occupy an orbit between the allowed ones). But what if I supplied a photon with energy $0.99E$, or $1.0001E$ or some such number. What will happen then?  I think that the electron should still undergo excitation precisely because the lines we observe in the line spectrum have some thickness. Which means that for a given transition, the atom absorbs frequencies in a certain range.   Is my reasoning correct? If not, why? How does Bohr's model explain this? How about modern theory?   If I'm right, what is the range of values that an atom can 'accept' for a given transition? Why do wheels appear to revolve opposite to the direction they are rotating? When viewing cars that are driving along side of us, sometimes their wheels appear to be turning backwards even though they are traveling in the same direction as our car. Why do they look that way? My installation is a Ubuntu 12.04 64 bits (Classic "legacy" MBR - No  EFI/UEFI here) with two partition :   A separate boot partition An encrypted LUKS volume that contains the system Logical Volumes   I seems I accidentaly deleted all the current kernel files with:  sudo apt-get purge 'linux-image-3.8*'    I applied the updates with Ubuntu Software Update, rebooted and then: Ubuntu can't boot.  I tried to boot on a live DVD with a 14.04.1 Ubuntu and can still see my partitions (described later):  /dev/sda1 (boot) /dev/sda2 (Encrypted volume) /dev/sda5 (Logical Volume container)  What are the steps to recover/reinstall the kernel files and dependencies in order to cleanly reboot my installed system?  Thanks in advance Was Severus Snape made a Death Eater before or after he told Voldemort about the Prophecy? Based on discussion in comments on , was Severus Snape a Death Eater (real one, with Dark Mark) before he overheard Sybil give the Prophecy to Dumbledore and relayed it to Voldemort? Or was he made a DE after that?  Canon sources only please (books/interviews/Pottermore) Couldn't find hvm kernel for Ubuntu tree This command:  virt-install   \    --name bla  \    --ram=1024  \    --disk path=/home/me/libvirt/images/bla.qcow2,bus=virtio,size=10  \    --location /home/me/Downloads/ubuntu-18.10-desktop-amd64.iso   Reports:  ERROR    Couldn't find hvm kernel for Ubuntu tree.   How can I fix this?  (Since there are many duplicate posts and answers with regard to this issue, I am answering it, too.) As the title says. How do I get from  $\frac{n}{\varphi(n)}$ to $\sum\limits_{d \mid n} \frac{\mu^2(d)}{\varphi(d)}$?  I know that $$\frac{n}{\varphi(n)}=\frac{\sum\limits_{d \mid n} \varphi(d)}{\sum\limits_{d \mid n} \mu(d)\frac{n}{d}},$$ and I suspect it is down this road I should go. But I get totally confused by the sums and I have no clue on how to divide them and "combine" them into one again. Any hints or advice would be much appreciated. How do I resize partitions using command line without using a GUI on a server? I only have access to the server via a terminal and I can't use graphical tools such as GParted! I want to create a new partition from a part of the root (about 768mb) for swap.  # df -h Filesystem      Size  Used Avail Use% Mounted on /dev/vda         20G  1.3G   18G   7% / udev             10M     0   10M   0% /dev tmpfs           199M  4.9M  194M   3% /run tmpfs           100M   12K  100M   1% /run/user tmpfs           5.0M  4.0K  5.0M   1% /run/lock I lost my Italian residence permit abroad, how can I obtain a duplicate so that I can fly back to Italy? Sweden is going to ban me from flying if I can't show them my lost permesso di soggiorno from Italy. It was issued in Florence because my old one expired while I was in school. How do I get a copy? I am using Google Chrome 48.0 32-bit. Today when I launched Google Chrome, I got this message:    This computer will soon stop receiving Google Chrome updates because this Linux system will no longer be supported   I thought Ubuntu 14.04 is supported for five years, what's exactly happening here?  And on 64-bit Ubuntu, I get an error from Update Manager and apt-get update:  Failed to fetch http://dl.google.com/linux/chrome/deb/dists/stable/Release  Unable to find expected entry 'main/binary-i386/Packages' in Release file (Wrong sources.list entry or malformed file)   Some index files failed to download.   They have been ignored, or old ones used instead. My Pakistani passport expires less than a month from now. I understand that some countries only let people in if their passport is valid for six months or more. Will I be able to enter Pakistan on a passport that is about to expire?  Also, travelling back to Pakistan is likely to involve transiting through some other country.  Does the six-month rule still apply to people returning to their country of citizenship? Choosing numbers without consecutive numbers. In how many ways can we choose $r$ numbers from $\{1,2,3,...,n\}$,   In a way where we have no consecutive numbers in the set? (like $1,2$) compare two columns of different files and print if it matches I am using Solaris 10 and so grep options involving -f don't work.  I have two pipe-separated files:   file1:  abc|123|BNY|apple| cab|234|cyx|orange| def|kumar|pki|bird|   file 2:   abc|123| kumar|pki| cab|234   I would like to compare the first two columns of file2 with file1 (search through the entire contents of file1 in first two columns) if they match print the matched line of file1. Then search for the second line of file 2 and so on.   Expected Output:  abc|123|BNY|apple| cab|234|cyx|orange|   The files I have are huge, containing about 400,000 lines, so I would like to make the execution fast. Give a combinatorial proof: $ n(n+1)2^{n-2} = \sum_{k=1}^{n}k^2\binom{n}{k} $ Find a combinatorial argument for the following binomial identity:   $$n(n+1)2^{n-2} = \sum_{k=1}^{n}k^2\binom{n}{k} .$$   Algebraic proofs can be found at  , and a related identity at  . Schengen area 90 days limit: Can I leave on the 91st day? Creating shapefile from Excel file in QGIS? I am using QGIS 2.6.1 and have worked in an Excel file database (which was actually converted from a Shapefile). I have managed to convert it as CSV file and load it into QGIS (displays data fine) but I have trouble to convert it to a shapefile.  I can view it but I can´t add or alter data in this file. I think I have to save it as a database.   Any clues how to convert the xlsl-data to a database and finally to a shapefile?