I'm kind of new to Ubuntu. A couple of days ago, I upgraded to 16.04 from 14.04. After the upgrade, I can neither install new software nor upgrade OS. When I enter   sudo apt-get upgrade   I get  this is my output:  Reading package lists... Done Building dependency tree        Reading state information... Done Calculating upgrade... Done The following packages will be upgraded:   apt apt-transport-https apt-utils gcc-doc libapt-inst2.0 libapt-pkg5.0  6 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. Need to get 2.011 kB/2.014 kB of archives. After this operation, 6.144 B of additional disk space will be used. Do you want to continue? [Y/n] y Get:1 http://mirror.ni.net.tr/ubuntu xenial-updates/main amd64 libapt-pkg5.0 amd64 1.2.12~ubuntu16.04.1 [696 kB] Get:2 http://mirror.ni.net.tr/ubuntu xenial-updates/main amd64 libapt-inst2.0 amd64 1.2.12~ubuntu16.04.1 [55,4 kB] Get:3 http://mirror.ni.net.tr/ubuntu xenial-updates/main amd64 apt amd64 1.2.12~ubuntu16.04.1 [1.038 kB] Get:4 http://mirror.ni.net.tr/ubuntu xenial-updates/main amd64 apt-utils amd64 1.2.12~ubuntu16.04.1 [196 kB] Get:5 http://mirror.ni.net.tr/ubuntu xenial-updates/main amd64 apt-transport-https amd64 1.2.12~ubuntu16.04.1 [25,7 kB] Fetched 2.011 kB in 2s (859 kB/s)          (Reading database ... 325999 files and directories currently installed.) Preparing to unpack .../gcc-doc_4%3a5.3.1-1ubuntu1_amd64.deb ... install-info: No dir file specified; try --help for more information. dpkg: warning: subprocess old pre-removal script returned error exit         status 1 dpkg: trying script from the new package instead ... dpkg: error processing archive /var/cache/apt/archives/gcc-    doc_4%3a5.3.1-1ubuntu1_amd64.deb (--unpack):  there is no script in the new version of the package - giving up install-info: No dir file specified; try --help for more information. dpkg: error while cleaning up: subprocess installed post-installation script returned error exit     status 1 Preparing to unpack .../libapt-pkg5.0_1.2.12~ubuntu16.04.1_amd64.deb     ... Unpacking libapt-pkg5.0:amd64 (1.2.12~ubuntu16.04.1) over     (1.2.10ubuntu1)     ... Processing triggers for libc-bin (2.23-0ubuntu3) ... Errors were encountered while processing:  /var/cache/apt/archives/gcc-doc_4%3a5.3.1-1ubuntu1_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   Using the error code below I searched for solutions in the AskUbuntu but couldn't find one that works.   Errors were encountered while processing:  /var/cache/apt/archives/gcc-doc_4%3a5.3.1-1ubuntu1_amd64.deb  E: Sub-process /usr/bin/dpkg returned an error code (1)   I have gcc-doc waiting to be upgraded in the Software Center. When I try to upgrade it on Software Center it takes forever and there is no upgrade. In Synaptics it halts the upgrade because of gcc-doc.  Thanks a lot for the help in advance.
I can't update my system because it freezes while installing a third-party update (zramswap-enabler)! Sometimes I get the following message in Update manager:  Could not initialize the package information An unresolvable problem occurred while initializing the package information. Please report this bug against the 'update-manager' package and include the following error message: E:The package zramswap-enabler needs to be reinstalled, but I can't find an archive for it.  I tried to remove the zramswap-enabler, but it's impossible because I get the following message: dpkg: error processing zramswap-enabler (--remove):  Package is in a very bad inconsistent state - you should  reinstall it before attempting a removal. Errors were encountered while processing:  zramswap-enabler E: Sub-process /usr/bin/dpkg returned an error code (1)  Actually I would really reinstall that package, but it is unable to do it! If I remove this third-party PPA then the system is warning me about a very very serious problem. So why can I not install/reinstall/remove/update this package and why freezes the updater if I try to update?
What is the most efficient way given to raise an integer to the power of another integer in C?  // 2^3 pow(2,3) == 8  // 5^5 pow(5,5) == 3125 What does this notation mean? F|U If $F$ is a function and $U$ is a set, then what does $F|U$ mean?   In , the Inverse Function Theorem, the notation is used  Also, the file in stating the Lemma 2.14 states that $A \in U$, what does this mean? A set is an element of another set? What is $A$?  EDIT: Could someone kindly explain to me what is going on in Lemma 2.16. How does $\delta$ come into play? I dont see the role in the lemma. I also don't see why this proves one-to-one Balancing long table inside multicol in LaTeX I would like to put some longer tabular data inside the multicols environment while maintaining its balancing abilities. I have tried supertabular with the trick to redefine \newpage as columnbreak. This isn't good though, because the columns aren't properly balanced. Finally I ended up using \halign:  \documentclass[11pt, a4paper]{article} \usepackage[margin=3cm]{geometry} \usepackage{supertabular} \usepackage{multicol}  \def\shortlipsum{\par Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Ut purus elit, vestibulum ut, placerat ac, adipiscing vitae, felis. Curabitur dictum gravida mauris. Nam arcu libero, nonummy eget, consectetuer id, vulputate a, magna. Donec vehicula augue eu neque.\par}  \newcounter{entryno} \setcounter{entryno}{1} \def\tabline{Test &amp; \the\value{entryno} &amp; Description\addtocounter{entryno}{1}\\} \def\tablines{\tabline\tabline\tabline\tabline\tabline} \def\mybreak{\hrule width \columnwidth height 0pt \columnbreak}  \begin{document} \begin{multicols}{2} \shortlipsum \medskip  % % This doesn't balance the columns. Whole table ends up in the left column (it fits) % \begingroup\let\newpage\mybreak % \noindent\begin{supertabular*}{\columnwidth}{@{\indent}l l l} % \tablines\tablines\tablines\tablines\tablines\tablines % \end{supertabular*} % \endgroup  \begingroup\let\\\cr \noindent\halign{\indent#\quad&amp;#\quad&amp;#\hfil\cr \tablines\tablines\tablines\tablines\tablines\tablines} \endgroup  \medskip \shortlipsum \end{multicols} \shortlipsum \end{document}     I was wondering if I'm the only one using \halign to achieve this result. On the other hand supertabular leaves me with an undesired almost empty right column. How would you approach this problem? I try to unzip a zip file, but got an error:  $ unzip COCR2_100.zip  Archive:  COCR2_100.zip   End-of-central-directory signature not found.  Either this file is not   a zipfile, or it constitutes one disk of a multi-part archive.  In the   latter case the central directory and zipfile comment will be found on   the last disk(s) of this archive. note:  COCR2_100.zip may be a plain executable, not an archive unzip:  cannot find zipfile directory in one of COCR2_100.zip or         COCR2_100.zip.zip, and cannot find COCR2_100.zip.ZIP, period.   I googled but didn't find a solution. I was wondering why it is and how I should fix it? Thanks!  The zip file can be downloaded from . It is an application, and here is its website .  My OS is 10.10. Lost my Downloads folder both from Dock and Finder I did something stupid apparently and lost my Downloads folder both from Dock and then when I opened Finder to drag it down to the Dock it somehow got deleted in the desktop.  Now although I can see the folder exists (e.g. by searching in Spotlight) I do not know how to restore it in the Dock and in Finder as well. Any help please? One of the most common gauges in QED computations are the $R_{\xi}$ gauges obtained by adding a term  \begin{equation} -\frac{(\partial_\mu A^{\mu})^2}{2\xi} \end{equation} to the Lagrangian. Different choices of $\xi$ correspond to different gauges ($\xi=0$ is Landau, $\xi=1$ is Feynman etc.) The propagator for the gauge field is different depending on the choice of gauge. The choice of Landau gauge forces $\partial_\mu A^\mu=0$, but I have never seen a similiar statement for the other gauges. I would like to know what constraint on the gauge field is produced by the other covariant gauges. For instance, what is the constraint on $A_\mu$ when $\xi=1,2,3,...$ etc. Is it still $\partial_\mu A^\mu=0$ or something different (it seems like it should be different)? How to evaluate the limit $\lim_{x\to 0} \frac{1-\cos(4x)}{\sin^2(7x)}$ How do I send a file as an email attachment using Linux command line? How to perform a logistic regression for more than 2 response classes in R I want to predict the impact of oil price over a Colombian oil company's stock price. I plan to use a logistic regression for this with a categorical variable (Up or Down given the direction of the stock price). Here is part of my dataset:  Minute  ecopet  profit  sum_profit   direccion  cl1_chg   sum_cl1    direccion_cl1 571     2160     0       10           Up         -0.03     0.00      Down 572     2160     0        0           Neutral     0.07    -0.03      Down 573     2160     0       -5           Down       -0.08     0.04      Up 574     2160     0       -5           Down       -0.07    -0.04      Down 575     2160     5       -5           Down       -0.08    -0.11      Down 576     2165     0       -25          Down        0.00    -0.19      Down 577     2165     0       -25          Down       -0.05    -0.19      Down 578     2165     0       -15          Down       -0.17    -0.24      Down 579     2165     5       -15          Down       -0.06    -0.41      Down 580     2170     0       -20          Down        0.03    -0.47      Down 581     2170    -10       0           Neutral     0.04    -0.44      Down   My dependent variable is 'direccion'. But as you can see it has 3 response classes. I know that to implement a binary logistic regression in R the code is:  glm.fit=glm(direccion~direccion_cl1, data=datos, family=binomial)   I am working with intraday information and plan to predict what happens when the oil moves up/ down (in the previous 10 minutes) and how it impacts the stock price in the next 10 minutes.  Could anyone tell me how could I perform this? I don't really know how to perform the logistic regression with 3 response classes. Thanks! While adding to an Answer to  question, I needed to use the above phrase, and I suddenly realised I was unsure whether to write "is" or "are".   There is more than one way to skin a cat. If there are more than one species of cat, we will flay each species differently.   I don't think that second example above sounds quite right to me (disregarding the meaning - sorry!), but in my original Answer I felt "is" would have been even worse.  Is "are" always wrong here? If so, what exactly is the rationale? If not, is there a case where it's unquestionably preferred – and why is that?    Note that in both the problematic Answer and my example attempting to mimic the same context more briefly, the writer doesn't know how many there are. There may be one, more, or even none.  Getting even more specific, the writer might have an opinion on how many there might be, and wish to convey his leanings by choice of verb form if language allows this to be done succinctly. How do you prevent a user from posting data multiple times on a website Is the distribution of an Ito diffusion at time t absolutely continuous wrt Lebesgue measure? I noticed that the locked message still references the FAQ. See :  locked by  yesterday This question exists because it has historical significance, but it is not considered a good, on-topic question for this site, so please do not use it as evidence that you can ask similar questions here. This question and its answers are frozen and cannot be changed. More info: .  Since the FAQ has been replaced by the , this message should provide a link there instead. Currently, the link actually takes you to the ; even if it doesn't link to the help center, the text should probably be something like &quot;More info: &quot;. How do keyboard input and text output work? Is there a tool to get the lines in one file that are not in another? Is there any tool that can get lines which file A contains, but file B doesn't? I could make a little simple script with, e.g, perl, but if something like that already exists, I'll save my time from now on. How / can you connect Ethernet devices together without magnetics? How do you wire it up? What sorts of practical limitations are there on doing this?  To clarify, I'm not trying to connect two computers here. I'm thinking specifically of creating a small network of microcontrollers on a single board. Lets say the total length of a network segment is no longer than 6 inches. This would be for 10BaseT or at most 100BaseT. How do I transfer data and settings from one Apple Watch to another? I have an Apple Watch. I have had it for a while. I just bought a new Apple Watch. (Both are Series 1, just different sizes.)  I would like to transfer all my data and settings from my old Apple Watch to my new Apple Watch and then sell my old Apple Watch.  Is it possible to migrate my profile from one Apple Watch to another?  If so, what is the procedure?  All the search results I have found have to do with moving an Apple Watch to a new iPhone or restoring a backup to the same Apple Watch. Perhaps it is possible to restore a backup from an old Apple Watch onto a new one? I have two user profile fields "Last Name" and "First Name". I also have a user list views. I want to expose "Name" as filter which can search for both Last Name and First Name. How can I do single filter of combination of those two fields? Can I create it from views UI?  One possible way is to create another profile field "Name" which will be hidden in the form. On user save, I would combine the two field values into the "Name" field and then expose it as filter in the views. But this solution is hard coding and it needs to write hooks. Systemd is really slow in comparison to upstart I have been using Ubuntu for a long time now, this is what happened when I use:  Systemd: It performs really bad using systemd: it uses 95% of the CPU all the time and the PC gets really hot. Also it takes a really long time to boot (about 1.5 min, and sometimes it does not boot at all as it has a black screen at boot.)  Upstart: When I tried the upstart options at boot, it performs as expected, booted in seconds, and it was awesome as it should be.  Laptop:   AMD A8 Radeon SSD   Questions:   Why does upstart perform better than systemd? How can I debug systemd? Should I switch to upstart? If yes, how do I do it? How should I setup separate MX records for a subdomain?