No Unity desktop after last kernel update
Blank screen after installing nvidia restricted driver
lstlisting - line number gaps Is it possible to add non-number characters on the left of a code block?  Specifically, I want to add ... to correspond with some source code (see image).    I am currently using commands to stop / start the line numbers. Here is the code:  \documentclass[12pt]{article}  \usepackage[a4paper, margin = 20mm, top = 30mm, bottom = 25mm]{geometry} \usepackage{xcolor, soul} \usepackage{listings}  \definecolor{codebackground}{rgb}{0.95, 0.95, 0.92}  \lstset {     frame            = tb, % hrule above and below     keepspaces       = true,     columns          = flexible,     basicstyle       = {\normalsize\ttfamily},     escapeinside     = {(*@}{@*)}, % for escaping     backgroundcolor  = \color{codebackground},     showstringspaces = false,     language         = C,     keywordstyle     = \color{blue},     stringstyle      = \color{red},     commentstyle     = \color{teal},     numbers          = left, % {none, left, right}     firstnumber      = 1,     numberstyle      = \scriptsize\color{black},     numbersep        = 5pt }  \let\origthelstnumber\thelstnumber \makeatletter % for stopping line numbers \newcommand*\stopnumber {     \lst@AddToHook{OnNewLine}     {         \let\thelstnumber\relax         \advance\c@lstnumber-\@ne\relax     } } % for starting line numbers \newcommand*\startnumber[1] {     \setcounter{lstnumber}{\numexpr#1-1\relax}     \lst@AddToHook{OnNewLine}     {         \let\thelstnumber\origthelstnumber         \refstepcounter{lstnumber}     } } \makeatother  \begin{document} \begin{lstlisting}[firstnumber = 456] int third_function(const int c) {     /* error checking */     if(c &lt; 0)     {         return;     } (*@ \stopnumber @*)      ...     (*@ \startnumber{512} @*)     /* other stuff */     int d = 4;     char* word = "third function"; (*@ \stopnumber @*)      ...     (*@ \startnumber{678} @*)     return (c * d); } \end{lstlisting} \end{document} I did not know that you could find an answer for that. However, I can only use Excel so far to do it.  How to calculate 3.6! by hand? Several lines of formulas to the left of one curly brace pointing to equation number How to make several lines of equations under one curly brace from the left side, such that it point to a reference number.  Now I do something like this:  \begin{align} \left. \begin{array}{ll} a = b + c \\ &amp; \dots  \\ a = b + c \\ &amp; \dots  \\ a = b + c  \end{array} \right\} \label{formulas}\\ \end{align}   But equation number appears in the bottom of curly brace. In PHP you can do:  print_r($var) or vardump($var)   which prints "human-readible" information about variable.  Is there equivalent functions / helpers for those in Ruby / Rails ? I have installed some apps through the Ubuntu Software center. How can I find the corresponding terminal command? For many apps, this is not the same as the displayed name. For example, the app called Text Editor can also be launched by typing "gedit" in the terminal, but how can I find this for other apps? How can I get Gnome3 to remember my session? Does the universe have a center? How to to calculate the hash of an unordered set Suppose I have a set of elements, with known hash (e.g. SHA-2). How can I calculate the hash of the set? With it I mean an unordered set, so the order of elements is undefined and shall not play any role in determining the hash of the set.  In theory any commutative operation applied to the hashes should be fine, but I have the strong feeling that XORing all of them together is quite unsafe. An attacker could add an element to the set to produce a hash collision, although finding an element with that wanted hash is as hard as breaking the hash of the whole set.  Anything better solution than the trivial one of sorting the elements into a list, calculating their hashes and then calculating the hash of the hash list?  I think Merkle trees can't help here if they are based on some sort of ordering of the elements. How can I repeat a command every interval of time , so that it will allow  me to run commands for checking  or monitoring  directories ?   There is no need for a script, i need just a simple command to be executed in terminal. I want to add this iostat command to my .bashrc and create an alias for it: iostat -xk 2 $(findmnt -T ~ | awk 'END {print $2}')  I'm adding this to my .bashrc: alias ios='iostat -xk 2 $(findmnt -T ~ | awk 'END {print $2}')'  Unfortunately, it doesn't work. If I run the above iostat command in a terminal it works, but when I run the ios alias it no longer works. And yes, I restart my shell every time. I am new to dslr's and got a nikon 3000 with 18-55 lens as a gift.  I already see some limitations with the lens for walking about or on trails.  So my question is being new should I go with a 55-200 or 55-300 or is there another step before I go with a telephoto lens. Is there a way to "rescue" mesh that has very bad topology? Unable to Enter a Country If I have a connecting flight through a country I am unable to enter. Can I retrieve my bags to recheck for my connect? Numerical Approximation of Differential Equations with Midpoint Method Should you gain rep for asking a duplicate question? HP laptop F1-12 keys inverted with Fn I recently bought an HP laptop. I'm pleased with it, save for one thing.  All the F1-12 keys are inverted. I mean the following:  All the F-keys have a symbol on it. Normally you would press Fn + your to use it. On this laptop, it's reversed. The symbol is what you get when you press the button normally and you have to press Fn + F-key to get the usual action.  So, if I want to refresh a webpage, instead of just F5, I have to do Fn + F5  I want to change this to regular behavior. Anybody know how I can do this?  Running Win7 Home premium, 64-bit. I tried to open Software Center using the command line   software-center   and it did work. I mean, Software Center opened and works fine, BUT, at the same time, in the Terminal window I see a lot of strange errors. How can that be? I'm puzzled.   Is there any explanation for this (and a fix for it)? I repeat, the app does open and it works fine, is only the lines in the background that show that something is not all right.  Here are the screen-shots with all the lines. Was Mjolnir ever used for building something? In the movie Thor (2011), while he was about to crown Thor as the next king of Asgard, Allfather Odin describes the mighty hammer Mjolnir as the following:      So long entrusted with this mighty hammer, Mjolnir. Forged in the heart of a dying star, from the sacred metal of Uru. Only one may ift it. Only one is worthy. Who wields this hammer commands the lightning and the storm. Its power has no equal -- as a weapon, to destroy, or as a tool, to build. It is a fit companion for a King.   We know Mjolnir as a weapon of destruction but are there references where it is used to build something? Root filesystem check fails after power failure during installation During the "install" phase of the upgrade there was a power failure. After when starting up again the following errors are reported:  init: udevtrigger main process (420) terminated with status 1 init: udevtrigger post-stop process (428) terminated with status 1 init: udevmonitor main process (419) killed by TERM signal The disk drive for / is not ready yet or not present Continue to wait; or press S to skip mounting or M for manual recovery   Pressing M gives me the following message:  Root filesystem check failed. A maintenance shell will now be started. CONTROL-D will terminate this shell and reboot the system. How to validate an email address in PHP