I am on a Ubuntu 17.04 Server and when trying to install Icinga2 per the , I get a dependency error.  root@PC:~# apt-get install icinga2 Reading package lists... Done Building dependency tree     Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies.  icinga2 : Depends: icinga2-bin (= 2.6.3-1~ppa1~xenial1) but it is not going to be installed E: Unable to correct problems, you have held broken packages.   Tried running apt-get install icinga2-bin and get the following  The following packages have unmet dependencies: icinga2-bin : Depends: libicinga2 (= 2.6.3-1~ppa1~xenial1) but it is not going to be installed Depends: libboost-program-options1.58.0 but it is not installable Depends: libboost-system1.58.0 but it is not installable Depends: libboost-thread1.58.0 but it is not installable E: Unable to correct problems, you have held broken packages.
Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (&gt;= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?
Scale-dependent displaying of a layer using OpenLayers plugin? When I am creating a layer in QGIS the layer position/lines does not stay the same when I zoom in closer than, it seems like 1: 1000. I am adding 2 images to explain the problem. The moment I zoom in closer than 1: 1 000 then the original layer does not display correctly anymore.  Please, can you assist in this matter? How are unmarketable market orders (other side of the order book is empty) matched with incoming orders? So this is a question with which I have been stuck for a while and it all revolves around the concept of volt.  I have posted a LOT of questions on physics forums while trying to understand the concept of volt and potential difference. This is hopefully going to be the last one.  What do you exactly mean when you say that a battery is 2.5 V. I know that it says that the potential difference between the 2 terminals of the battery is 2.5 V  but then what is the potential of the 2 ends of the battery? Is there a unit of potential and not just potential difference?  Also volt = work/charge but how can work/charge express the difference of potentials across the 2 terminals? How do I attach rope to a mesh I am trying to make a pirate ship and am trying to attach rope to the sails. my rope is made using a path, and soft body physics. I can not find a way to attach my rope to the sail. and I can not use pinned vertices because this is not a cloth modifier. How do you reverse a string in place in C or C++? How do you reverse a string in C or C++ without requiring a separate buffer to hold the reversed string? I would like to restore LightDM to its default state, because for some reason /etc/lightdm/unity-greeter.conf is now an empty file.  Deleting /etc/lightdm/unity-greeter.conf and then running sudo apt-get install --reinstall unity-greeter doesn't create a new config file as you might expect.   How can I restore a missing config file? Is it ok to use an alternate account while my main user is restricted? I'm new to Stack Exchange, and my main user only has 16+ rep. And it's been blocked in Code Review. I need to use Code Review today. Should I use an alternate account? Parallel website running a copy of my original website We have been working on a gaming website. Recently while making note of the major traffic sources, I noticed a website that I found to be a carbon-copy of our website. It uses our logo, and everything else the same as ours, but with a different domain name.   Their domain name is not however pointing to our site because at several places the links are like: carbonccopy-website/our-links. This website even has links to some images as: carbonccopy-website/our-images.   How could they have done that, and what can I do to stop it? How do you make sure email you send programmatically is not automatically marked as spam? I think it's well established that for the basic premise in the Back to the Future Trilogy to work, we have a system of alternate timelines.  If this is the case though, then why would Marty in Back to the Future (the original) begin to fade?  Logically, there would simply be no Marty in the alternate timeline created when Marty travels back to 1955 for the first time; why should this affect the original Marty from the original timeline? Using a comma before "but" There is a remote Windows server on a private network which I can connect to via Remote Desktop Connection.  I would like to be able to make TCP/IP connections from my computer to other computers on that server's network.  Remote Desktop Connection makes it possible to share printers, drives, and other local resources through the connection.  Is there any way to "tunnel" a TCP/IP connection via RDC?  I'd like something similar to the port-forwarding provided by SSH.  I don't see any way to do this via RDC, but I'm hoping the capability is there and I just don't know about it. Simple question.   SO had turned me into a better developer by far, I like to browse questions that strike my interest and curiosity and just read through the answers. I never fail to learn something new everyday, whether it's something trivial or something much more complex.  When I receive reputation it means a lot to me, almost a self achievement of sorts. Something I can show to someone to prove my "worth". I think it works for me as a great confidence booster, also its something I can show my friends who don't understand what I do.   It almost feels like I can finally have something to back me up if need to be.  So the question is what does YOUR reputation mean to YOU? Is it simply a number, is it a score as if you're playing a game, or does it help you mentally achieve your goals and improve yourself like it does for me. In German, we often use "Elfhundert" (literally, "eleven hundred") for 1100 or "neunzehnhundert" ("nineteen hundred") for 1900; but is this correct in English? If every ideal is principal show the same is true for the image of a homomorphism. Apologies if this has been asked somewhere before, but I didn't see what I was looking for after several pages of Google results.  I was reading Jech's The Axiom of Choice and was introduced to the equivalence of the ultrafilter lemma and the compactness theorem for FOL. I gather that these are also equivalent to the completeness theorem. I am primarily interested in trying to understand the "ultrafilter lemma $\implies$ completeness/compactness" direction. Jech's own proof takes an odd route through "binary messes" and I don't really follow the last couple of steps. (It's on pp.17,18 of the 2008 Dover reprint, if one is interested).  I'm wondering if anyone knows a good reference for, or can provide, a readable proof that the ultrafilter lemma implies completeness or compactness, with a preference for completeness. Alternatively, if you have Jech's book on hand, helping me bridge the concluding paragraph of his $\textrm{(ii)}\implies\textrm{(iii)}$ step with the preceding steps would clear up much of my puzzlement. (Though in this case I can't offer any help in saying what, specifically, is missing in the way of a bridge). What is Java's answer to WPF? Does a photon exert a gravitational pull? I know a photon has zero rest mass, but it does have plenty of energy. Since energy and mass are equivalent does this mean that a photon (or more practically, a light beam) exerts a gravitational pull on other objects? If so, does it depend on the frequency of the photon? What is this "forbidden" icon in my systray? The following is a systray applet icon that appeared in my Unity session after I upgraded to Ubuntu 16.10. Its menu is tall, narrow and empty. What is it? I am following Carroll's GR book. He explain that it is convention to parameterize geodesics of photons by a parameter $\lambda$ such that  $$p^\mu ~=~ \frac{d x^{\mu}}{d \lambda}.\tag{3.62}$$  But this is the definition of 4-velocity for a massive particle in the case of $\lambda=\tau$ equal to proper time. My question then, is $$u^\mu = p^\mu$$ for all massless particles? I ask because it's well-known that proper time $\tau$ freezes for massless particles.