I am trying to launch a cron job every hour (an interactive system upgrade).  The code that does the actual update ( a no-password sudo yum update) is in my .zshrc (I use zsh as my shell). To launch zsh, I am invoking a new terminal process, so I have /usr/bin/gnome-terminal as the process. I have an email from cron saying that the command errorred out with "Failed to parse arguments: Cannot open display:" This is strange, since the command works fine from a terminal.  How do I fix this problem?
How do I get a gnome-terminal window to open from a crontab?  I have tried this:      * * * * * /usr/bin/gnome-terminal       * * * * * source /home/user_name/.bashrc ; /usr/bin/gnome-terminal      * * * * * source /home/user_name/.profile ; /usr/bin/gnome-terminal      * * * * * source /home/user_name/.bashrc ; /home/user_name/bin/opengnometerminal.sh   None of these seem to work.
Show that if $p$ is prime then $\Bbb Z_p$ is a field Check my proof please.  Let $\Bbb Z_p:=\Bbb Z/p\Bbb Z$ be the quotient ring modulo $p$. I want to prove that if $p$ is prime then $\Bbb Z_p$ is a field.  Known facts about the quotient rings of the kind $\Bbb Z_n$ (I dont list all the characteristics of a ring, just some ones):   They are commutative rings with unity. $[0]=[n]$ is the identity of addition or zero. Then $[n]+[a]=[a]$ and $[n]\cdot[a]=[n]$ for all $[a]\in\Bbb Z_n$. $[1]$ is the multiplicative identity or unity. Then $[1]\cdot[a]=[a]$ for all $[a]\in\Bbb Z_n$. The addition is defined as $[a]+[b]=[a+b]$, and the multiplication is defined as $[a]\cdot[b]=[ab]$. $[a]=[b]$ means that exists $z\in\Bbb Z$ such that $a=b+nz$. $|\Bbb Z_p|=p$.   A ring $\Bbb Z_p$ dont have zero divisors, i.e. doesnt exist $[a],[b]\in\Bbb Z_p$ distinct of $[p]$ such that $[a]\cdot[b]=[p]$. Proof by contradiction: suppose that exists such $[a],[b]$ distinct of $[p]$ that are zero divisors. Then exist some $z_j\in\Bbb Z$ such that:  $$(a+pz_1)(b+pz_2)=pz_3\iff ab+pz_4=pz_3\iff ab=pz_5$$  but this is a contradiction with the assumption that $a,b\neq p$ and $p$ prime, so dont exist divisors of zero on any $\Bbb Z_p$.$\Box$  For any $[a]\in\Bbb Z_p$ distinct of $[p]$ exist $[b]$ such that $[a][b]=[1]$. Because $\Bbb Z_p$ dont have zero divisors and is finite for some $[a]\neq[p]$ we have that if $[b]\neq[c]$ then $[a][b]\neq[a][c]$. Proof by contradiction: if $[a][b]=[a][c]$ in the above conditions then  $$[a][c]=[ac]=[ab]=[a][b]\iff ac+pz_1=ab+pz_2\iff a(c-b)=pz_3$$  for some $z_j\in\Bbb Z$. But $pz_3\in[p]$, then $[a][c-b]=[p]$ but because there are no zero divisors in $\Bbb Z_p$ then or $[a]=[p]$ or $[c-b]=[p]$ what contradicts the above conditions.$\Box$  Because $[a][b]\neq[a][c]$ for $[a]\neq[p]$ and $[b]\neq[c]$ then for any $[a]\neq[p]$ we have that  $$[a]\cdot\Bbb Z_p=\Bbb Z_p\implies \exists [b]\in\Bbb Z_p:[a][b]=[1]$$  In other words: every element of $\Bbb Z_p$ but $[p]$ have a multiplicative inverse as stated above.$\Box$  Because $\Bbb Z_p$ is a commutative ring with $[1]\neq[0]$ and have multiplicative inverse for all their elements but $[p]=[0]$ then $\Bbb Z_p$ is a field.$\Box$ What is a proper way to clean a 35mm negative film stripe before scanning?   What chemicals can remove fingerprints, dust that does not come off by blowing, or strains of glue? What type of cloth does minimal damage when rubbing off dirt? I was using this command to use a custom crafting table:  /execute @a ~ ~ ~ detect ~ ~-1 ~ dropper 1 {Items:[{id:minecraft:blaze_rod,Slot:1b,Count:1b,Damage:0s},{id:minecraft:blaze_rod,Slot:4b,Count:1b},{id:minecraft:stick,Slot:7b,Count:1b}]} /scoreboard players set @p LSC 1   But I get this error message when I stand on a dropper with these items:     Failed to execute '{Items:[{id:minecraft:blaze_rod,Slot:1b,Count:1b,Damage:0s},{id:minecraft:blaze_rod,Slot:4b,Count:1b},{id:minecraft:stick,Slot:7b,Count:1b}]} /scoreboard players set @p LSC 1' as TrevMCC38   By the way, Im in 16w06a Why does my Nikon D3100 give the error "Lens not attached" with a Vivitar 200 telephoto lens? I have a Nikon D3100 camera, and am trying to use an "Automatic Fixed Mount Vivitar 200mm lens" with it. When I attach the lens, I get the message "Lens not attached". and nothing works. HELP!  I can't easily take it to a camera shop, as I live in the Mojave Desert, about 200 miles away from any camera shop. This is a new lens, and a new camera. How to safely remove proprietary Intel driver I recently installed the proprietary Intel drivers for my Toshiba Satellite A105 s4284 running Ubuntu 14.10. Nouveau was working just fine, I was just attempting to make it so that I was able to run CS:S (no need for explanation on that.)  Long story short, I went and downloaded the Intel Graphic Drivers for Linux* from . After downloading and installing the .deb, I ran intel-linux-graphics-installer which opened up a window that downloaded &amp; installed the open Intel drivers. I then rebooted, and it's slow. Very slow, especially on 3D effects and when I hit Alt+Tab.  Now, I don't know if the previously installed Nouveau drivers are conflicting with these new Intel drivers (if that's the issue, what should I do about fixing it?) What I do know is that my system isn't behaving right and I want it to (obviously.) If removing the Nouveau drivers isn't the solution, how can I safely remove the just-installed Intel drivers?  Does anyone have any suggestions? I had Windows 8 installed on my system, which I screwed up, and now I run Ubuntu 12.04. While installing, Ubuntu used all the 461 GB of HDD space (one partition).   Now I want to make a new partition of maybe 100 GB or so, in order to install Windows 7 alongside Ubuntu (with a dual-boot). But I can't even get a partition done. I can't change the partition in GParted either - the option is disabled. "strlen(s1) - strlen(s2)" is never less than zero Unable to install LanguageTool 2.5 extension for LibreOffice 4.2 on Ubuntu 14.04 I am not able to install LanguageTool extension for LibreOffice. Getting exception when I try to install it.   p.s. Somebody says that the solution is installing openoffice.org-java-common package but Ubuntu 14.04 does not have this package in its repository.  System details:  OS: Ubuntu 14.04 LTS  LibreOffice: 4.2 (4.2.3.3)  LanguageTool: 2.5  Java: Oracle JDK 1.8.0_05     Exception message: How to make the space under footnotes disappear? How do I make the space under footnotes disappear? And to space over the footnote's bar?    Code:  \documentclass[12pt,french]{report} \usepackage{mathptmx} \usepackage{helvet} \usepackage{courier} \usepackage[T1]{fontenc} \usepackage[cp1250]{inputenc} \usepackage[a4paper]{geometry} \geometry{verbose,margin=1in,headheight=12pt,headsep=25pt} \usepackage{fancyhdr} \pagestyle{fancy} \setlength{\parskip}{\medskipamount} \setlength{\parindent}{0pt} \usepackage{babel} \makeatletter \addto\extrasfrench{%    \providecommand{\og}{\leavevmode\flqq~}%    \providecommand{\fg}{\ifdim\lastskip&gt;\z@\unskip\fi~\frqq}% } \makeatother \usepackage{latexsym} \usepackage{pifont} \usepackage{color} \usepackage{float} \usepackage{textcomp} \usepackage{graphicx} \usepackage{setspace} \usepackage[unicode=true,  bookmarks=true,bookmarksnumbered=true,bookmarksopen=false,  breaklinks=true,pdfborder={0 0 0},backref=false,colorlinks=false]  {hyperref} \hypersetup{pdftitle={tito},  pdfauthor={abc},  pdfkeywords={kiko}} \usepackage{lipsum}  \makeatletter \usepackage{multicol} \usepackage{fancyhdr} \usepackage{multirow} \usepackage{longtable} \setcounter{secnumdepth}{4} \setcounter{tocdepth}{4} \usepackage{array} \newcommand{\ts}{\textsuperscript} \renewcommand\theparagraph{\alph{paragraph}.} \renewcommand\paragraph{\@startsection{paragraph}{4}{\z@}%                                     {3.25ex \@plus1ex \@minus.2ex}%                                     {0.5ex \@plus .2ex}%                                     {\normalfont\normalsize\bfseries}} \renewcommand*\l@paragraph{\@dottedtocline{4}{10em}{2em}}  \def\thickhrulefill{\leavevmode \leaders \hrule height 1ex \hfill \kern \z@}  \def\@makechapterhead#1{% \vspace*{10\p@}% {\parindent \z@ {\reset@font \usefont{OT1}{phv}{m}{n} \LARGE Chapitre \thechapter\par\nobreak}% \par\nobreak \vspace*{30\p@} \interlinepenalty\@M \usefont{OT1}{ptm}{b}{n} {\raggedright \Huge #1}% \par\nobreak \vskip 20\p@ \hrule height 1pt \par\nobreak \vskip 45\p@ }}  \def\@makeschapterhead#1{% \vspace*{10\p@}% {\parindent \z@ {\raggedleft \reset@font \scshape \vphantom{\@chapapp{} \thechapter} \par\nobreak}% \par\nobreak \vspace*{30\p@} \interlinepenalty\@M \usefont{OT1}{ptm}{b}{n} {\raggedright \Huge #1}% \par\nobreak \par\nobreak \vskip 45\p@ }}  \lhead{\nouppercase\leftmark} \chead{} \rhead{} \lfoot{} \cfoot{\thepage} \rfoot{} \renewcommand{\footrulewidth}{0.4pt}  \pretolerance=10000 \hyphenpenalty=10000 \exhyphenpenalty=10000  \AtBeginDocument{   \def\labelitemi{\Pisymbol{psy}{183}}   \def\labelitemii{\(\rhd\)}   \def\labelitemiii{\(\rhd\)}   \def\labelitemiv{\(\ast\)} } \makeatother  \begin{document} \chapter{Chap} \lipsum[1]\footnote{\lipsum[1]} \lipsum[1-8] \end{document} I'm on the hunt for a great sounding, non-in-ear set of headphones with working mic, play/pause, and volume buttons.  I have Bang &amp; Olufsen's , which are among the best sounding headphones I've ever used. And all three button work perfectly in my MacBook Air and iPhone.  Obviously they don't work perfectly in my Nexus 4, since Android devices uses a different way of reading volume up/down buttons.  So, my question is rather simple, does anyone know how to make them work with Android, or alternatively any equally good headphones to the EarSet 3i's that work on Android? And to make it extra challenging, no in-ear ones please, cause I can't stand them :(  Or maybe anyone knows of some kind of adapter cable that can be used between an Android phone and iPhone compatible headphones to translate the volume button signals so the Android device understands them? Whole disk unallocated? Gparted error or partition overlapping? Creating node shapes Linux file access monitoring Is there any way in unix to find out who accessed certain file in last 1 week? It may be user or some script ftp it to some other place. Can I get a list of user name who accessed certain file? How can I find out who is accessing particular file?? How to create posters using LaTeX I want to create posters for my poster presentation on a conference. What tools or LaTeX classes are available for preparing posters ? phpmyadmin doesn't connection with true data Reading a Set in PostLoad on JPA/Hibernate How can I find the XY coordinates of an HTML element (DIV) from JavaScript if they were not explicitly set? I have a good intuition that $A$ is independent of $B$ if $P(A \vert B) = P(A)$, and I see how you can easily derive from this that it must hold that $P(A,B) = P(A)P(B)$.    But the first statement is not normally taken as a definition; instead the second is.    What is the intuition, or even derivation behind defining $A$ and $B$ as independent iff $P(A, B) = P(A)(B)$?    The kind of explanation I am looking for would be one similar to that given by Jaynes for the definition of conditional probability in the first chapter of Probability: The Logic of Science, or even a Kolmogorov axiomatic explanation would help. In the Phone app (iPhone 5, iOS 6.1.2), I click on a contact's number, the call is initiated and starts ringing.   For a brief moment at this point, the label of the number (home / work / etc…) is displayed alongside the contact's name, but it quickly is removed and replaced with the call timer counting up and only the name (and picture of the contact) are shown.      How can I see the number that is being called during a phone call? Decide if the series converges and prove it using comparison test: $\sum_{k=1}^{\infty}\frac{1}{2k+3}$ Decide if the series converges and prove it using comparison test:   $\sum_{k=1}^{\infty}\frac{1}{2k+3}$   $$\frac{1}{2k+3} &lt;\frac{1}{2k}&lt;\frac{1}{k}$$  and since $\sum_{k=1}^{\infty}\frac{1}{k}$ diverges (we have defined that in our readings, so I can claim it here), the complete series will diverge, too.  Did I do everything correctly? What makes me feel a bit unsure is that there is no "$\leq$" sign anywhere and when I look up the comparison test on the internet, I don't see any "&lt;" or ">" in the definition.  Is it correct anyway?