I wanted to know the  of a certain software (omc), so I ran first    which omc file /usr/bin/omc   and that gave me all information I needed. Before telling my colleagues, I wanted to shorten it to a single line:    which omc | file   but that did not work. But why not?
I've been studying about the command line and learned that | (pipeline) is meant to redirect the output from a command to the input of another one. So why does the command ls | file doesn't work?  file input is one of more filenames, like file filename1 filename2  ls output is a list of directories and files on a folder, so I thought ls | file was supposed to show the file type of every file on a folder.  When I use it however, the output is:      Usage: file [-bcEhikLlNnprsvz0] [--apple] [--mime-encoding] [--mime-type]         [-e testname] [-F separator] [-f namefile] [-m magicfiles] file ...     file -C [-m magicfiles]     file [--help]   As there was some error with the usage of the file command
Background Video is shown in Rendered mode but not when szene is rendered i have a 3D Object and want to add a background image( if possible even a movie) to this 3D Object. I use Cycles to render and tried a plane with the  image as texture. When i go into render mode, it looks like this(picture with background) and when rendered, it has no background. The key also looks into  a different direction.  Should i even use Cycles for this or use motion tracking? i tried to use that but had several problems.     Rendered mode   When scene is rendered Black screen after installation of Ubuntu 18.04 I did a fresh complete install of Ubuntu 18.04 on my ASUS M32CD desktop.   Everything during install went fine. At the end it said it was complete complete, and would reboot. Popped the disc out. Rebooted itself back into bios so I changed it back from CD boot as primary to HD.  When it booted up for Ubuntu screen and then everything went black and can’t do anything now! Ugh. Help examples:         Gift (German) = poison   poisson (French) = fish   embarazada (Spanish) = pregnant   sauce (Spanish) = willow   triviale (Italian) = vulgar   parentes (Portuguese) = relatives   slim (Dutch) = smart I've had a few concerns over a new form of &quot;spam&quot; - that is, through voting. A while back, I had seen some wild reputation increases to my account, amongst others, that seemingly felt weird - as I've barely participated in asking questions or providing answers. Earlier today, this sentiment was echoed by another user in chat:  and like 250 this month? it seems like someone is spam upvoting  This was another user that saw a 250 rep increase, but has been inactive for quite a while. For a site that hasn't seen more than 5 questions a day, that was really weird. To put things even more out of hand, it seems like each vote has been placed on a question.  I did some investigation of my own, and it seems like I've found a badge hunter. More of a... gold badge hunter. This user is among the top 3 voters of the site. Looking into this user's profile, this user only has under 200 rep, and has posted a single question, which was received differently. One thing caught my eye:  Votes all time              by type 581   up              535    question 1     down            47     answer   Each vote is an up vote (with the exception of one), and there are 535 up votes on questions. There are 535 questions in the entire site. Using reputation stats from user profiles, I came with the conclusion that these votes are...  Done within a short period of time. 5 question votes within a couple of minutes Done in [near] perfect chronological order: The earlier the vote, the earlier the question was asked. As if the user had gone through the list of questions in order, and placed an up vote on each one.   I see this as incredibly problematic. First:  It dangerously inflates reputation. Votes are not done based on their content, but simply for voting. Therefore, reputation loses it value as a way to measure expertise.  It's like serial up voting. Generally, when we hear the term &quot;serial up voting&quot;, we think of a voting ring, where one user continuously up votes another. This is negative for the targeted user. Well, here, we've got a voting ring with the site and this user. A user continuously up votes the site, causing negative damage for the site.  We mix good and bad content. Since low quality questions are a victim of the voting spree, many get meddled with the rest of &quot;good quality&quot; questions, despite being closed as off-topic, too broad, or whatever the reason. We can no longer reliably sort questions by quality with the very system that was designed to help us.   ... And the rest of voting fraud issues outlined in .  I've got a couple questions on this:  Is this comparable to serial voting? Should such votes be reversed? How should we determine whether or not to reverse them?  Should we stop this? Let it be? Is this really that big of a problem for sites? (I would argue that it's less of an issue for graduated sites that receive large amounts of content, but what about beta sites that rarely see more than a few questions a day) Why do some AC adapters and power supplies generate a whining noise, and what can I do about it? Could someone provide me with a good explanation of why $0^0=1$?  My train of thought:  $x&gt;0$  $0^x=0^{x-0}=0^x/0^0$, so  $0^0=0^x/0^x=\,?$  Possible answers:   $0^0\cdot0^x=1\cdot0^0$, so $0^0=1$ $0^0=0^x/0^x=0/0$, which is undefined   PS. I've read the  on mathforum.org, but it isn't clear to me. Subject-verb inversion / verb-subject-object -- is this correct? I recently read the following in a schoolbook:     Wrote the researchers, "[...]"   I wonder if this is correct English. I have seen it a couple of more times. Is this just a matter of preference? English doesn't really have a very liberal word order, unless you're writing poetry or the like.  Can anyone tell me what this is called? I found some information on subject-verb inversion, but it only seems to be when the object is in front, but in this case, the word order is verb-subject-object. How do I get the distinct/unique values in a column in Excel? If I have a column with values, and I want to find out what distinct values are in there (not how many - but the actual distinct values), how can I do that?  In SQL Server I would do something like   SELECT Distinct(MyColumn) FROM MyTable C++ catching all exceptions Is there a c++ equivalent of Java's  try {     ... } catch (Throwable t) {     ... }   I am trying to debug Java/jni code that calls native windows functions and the virtual machine keeps crashing.  The native code appears fine in unit testing and only seems to crash when called through jni.  A generic exception catching mechanism would prove extremely useful. How to easily and completely disable/enable WLAN (so it cannot be turned on again while travelling)? Without going into specifics of why I might like to do this, or whether this is a good idea or not, I would like to know how I can disable use of wireless networking on my MacBook Air, either via removal of software or drivers or similar, such that the machine is unable to connect to a WIFI network in any way without I undo those changes.  The intention is for the machine to be unable to communicate wirelessly when out of the house, and for those changes to not be easily reverted until I return (for example requiring some piece of external storage that does not travel with me and which contains copies of whatever I have removed). How can I easily remove and then re-allow WIFI access (without losing my stored profiles/passwords or disturbing anything else)? Is it possible to simply copy a certain app or plugin to an external drive, delete it from my laptop, and later copy it back, again having everything as it was before?  One year later I have been happily using Daniel Lawson's solution below for quite some time now. I have created two applications with automator, one that deletes the .kext, one that restores it from an USB stick. First, copy /System/Library/Extensions/IO80211Family.kext to a USB stick and leave that stick at home. Open Automator, select to create an &quot;Application&quot;, then choose &quot;Utilities&quot; from the &quot;Library&quot;, then &quot;Execute Shell Script&quot;. (I'm translating this from my German menus, so the exact names may differ.) For the &quot;Disconnector&quot; app, enter the following into the text area of the &quot;Execute Shell Script&quot; event: echo YOUR_ADMIN_PASSWORD | sudo -S rm -rf /System/Library/Extensions/IO80211Family.kext  Replace &quot;YOUR_ADMIN_PASSWORD&quot; by your admin password. Then save the app and drag its icon to the Dock. Now, when you are sure you want to be free of all online distractions, click the app icon, and the IO80211Family.kext is gone. Just restart your laptop and you can no longer connect to WLAN:  For the &quot;Reconnector&quot; app, enter the following into the text area in Automator: echo YOUR_ADMIN_PASSWORD | sudo -S cp -r /Volumes/NAME_OF_YOUR_USB_STICK/IO80211Family.kext /System/Library/Extensions/  Replace &quot;YOUR_ADMIN_PASSWORD&quot; by your admin password and &quot;NAME_OF_YOUR_USB_STICK&quot; by the name of your USB stick. Save the app etc. Now when you return home, insert the USB stick that carries the IO80211Family.kext into your laptop, click the Reconnector app icon and then restart your laptop. Now you can connect to WLAN again. Note. There are some security issues invovled when you echo your admin password, because by that it is written to the shell history and can be found there. I don't care, but you might, depending on your circumstances. How to open a terminal from within Atom? I'm currently working with Atom, and sometimes I want to open a terminal on the directory my working file is. To do this, I usually have to open the folder in nautilus (right clicking the file in atom) and then I open a terminal on that directory from nautilus (right click).  I wonder if there is a way to open the terminal in the file directory without having to open nautilus first. There is already a similar post, that has an answer to my question, but it is quite short and I don't get it... So I am trying to show that  \begin{align} \{e_K |~ K \subset G~ conjugacy~ class \} \end{align} is a basis for $Z(\mathbb{Z}[G])$. Serre even writes "one immediately checks that the $e_K$ form a basis", but even reading the other post  I don't see that...  My approach to this is:  Be $x \in Z(\mathbb{Z}[G])$, which is equivalent to: $x = gxg^{-1}$ for all $g \in G$. Writing  $x = \sum\limits_{h \in G} \lambda_h h$, we get $x = \sum\limits_{h \in G} \lambda_h ghg^{-1}$. I don't really know how to go on at this point. I mean, I know that when $a,b \in K$ (same conjugacy class) you get $\sum\limits_{s \in K} \mu_s s = \mu\sum\limits_{s \in K} s$, since \begin{align} a = hbh^{-1} \Rightarrow \mu_a = \mu_b ~\forall a,b\in K \end{align} So all elements in the same conjugacy class have the same scalar.  But from here I don't really know how I can generate the $x = \sum\limits_{h \in G} \lambda_h ghg^{-1}$ with the $e_K$ ...  I would be really thankful, if someone could give me quite a basic proof that even I understand... Why do I give my pets "food" but my livestock "feed"? When I feed my cat or my dog, the package tends to say "Dog Food" or "Cat Food."  In contrast, I give my chickens "chicken feed" or "poultry feed."  Likewise, a cow's silage is her "feed."  Why does this distinction exist?  Is there an historical or grammatical explanation, or is it merely idiom? Extrusions causing problems in edit mode When I extruded vertices in edit mode, for some reason one of the sides of my 3-D model (the textured-looking side to the right) is creating a lot of errors. First off, it automatically sets extrusions on the x-axis. Secondly, it doesn't allow me to extrude planes into 3-D shapes. Thirdly, I can't increase the height of vertices without it creating a new face. Finally, it renders those automatic textures to create a grainy black texture in render mode. I attached an image with the solid object (top) and the rendered object (bottom). Note: I did not set any textures or alter the lighting on the model. Also, the left gray side is working perfectly fine without errors. In the , the icon color for the various sites seems* incorrect: Whenever I select a main site, the icon is greyed out, and when ever I select the corresponding meta site, the icon is colored. My initial instinct was to think that the colors of the main/meta sites following the &quot;Switch sites:&quot; prompt should be switched. (Actually, it seems like it's just a UI thing. See the edit below.)  *Edit: Actually, the colors are technically not incorrect, since (as Jeremy Banks has pointed out) the icon shows &quot;the other&quot; site of the main/meta pair, and clicking on it is for switching to the respective other site. See the comment thread for some UI improvement ideas. Does this email mean that I have been granted the visa? I received the following email this morning. Does it mean that my visa has been granted?  UK Visas &amp; Immigration has now assessed your UK visa application and made a decision. Your documents and the decision will be sent back to either the UK Visa Application Centre where you applied, where we will contact you by email over the next few days to collect them, or if you are using the courier return service, will be sent directly back to the address provided. Please note that TLScontact does not know the outcome of the assessment and has played no role in the decision-making process. Kind regards, TLScontact UK VIsas &amp; Immigration Can I visit the UK with an EU permanent residence card? I am non EU national, living in a Schengen country for past 5 years. I hold Indian passport and EU permanent residence card valid for 5 years.   Can i go to UK for few days to visit friends without a visa?  I am aware that UK is not in Schengen, and Schengen visas and residence permits issued by Schengen country is not valid for United Kingdom? But what about the PR card issued by a Schengen country?  I am also aware that EU citizens carrying EU passport have no restrictions to visit UK. What's the scope of a variable initialized in an if statement? Laplace equation of composite function Suppose we have $f(x,y)$, which satisfies Laplaces equation: $\frac{\delta^2f}{\delta x^2}+\frac{\delta^2f}{\delta y^2}=0$  Does $f(\frac{x}{x^2+y^2},\frac{y}{x^2+y^2})$ also satisfy Laplace equation? Can I get from Gatwick airport to London by Oyster card? I read many contradictions as to whether one can use a Oyster card from Gatwick Airport to central London.  What is the most time-efficient way to go from Gatwick to "Old Billingsgate" (Monument tube station is nearby)? Public transportation is preferred over taxi.