Before attempting to run this be sure that the current running Kernel headers are installed on your system. If you don&#39;t you will receive an error indicating that you need to install them or use the --kernelsource option to point to said headers. 


Following the directions on this [blog post][1] helped me. Basically after you install those two packages you also need to do the reconfiguration:

    sudo dpkg-reconfigure virtualbox-dkms

    sudo dpkg-reconfigure virtualbox


  [1]: http://blog.erikaheidi.com/2012/10/30/solving-virtualbox-problem-in-ubuntu-gnome-remix-12-10/

After the two `dpkg-reconfigure` commands I also needed to run:

    sudo modprobe vboxdrv

And to fix eth0: 

    sudo modprobe vboxnetflt

If you have the same problem in ubuntu 12.04 the above solution might not work (at least it didn&#39;t work for me and another two - see the error I was getting in note#1 bellow). [Installing the Oracle version of Virtualbox][1] however worked just fine.


----------


Note #1: I was getting the errors below:

    ndemou  ~ dkms status
    virtualbox, 4.1.12: added
    ndemou  ~ sudo dkms install virtualbox/4.1.12
    Kernel preparation unnecessary for this kernel.  Skipping...
    
    Building module:
    cleaning build area....
    make KERNELRELEASE=3.5.0-28-generic -C /lib/modules/3.5.0-28-generic/build M=/var/lib/dkms/virtualbox/4.1.12/build.....(bad exit status: 2)
    Error! Bad return status for module build on kernel: 3.5.0-28-generic (i686)
    Consult /var/lib/dkms/virtualbox/4.1.12/build/make.log for more information.


  [1]: https://www.virtualbox.org/wiki/Linux_Downloads

Is there a shorter way to find the first element in an array meeting some conditions than this:

    my_array[ my_array.index {|x| x.some_test} ]


First element of an array with condition

[My blog](http://blog.EverCoding.net) is built with Jekyll on Github. In the navigation bar, the default order is Pages, Messages, About, Archives. I want to change the list to Pages, Archives, About, Messages. What should I do?

I think it is related to the code below

    {% assign pages_list = site.pages %}

I think `site.pages` is what I should change, but I don&#39;t know how.


How to change the default order pages in Jekyll?

Here is how the error output is if I run `virtualbox` from the terminal. How to correct it? I am on a Ubuntu 12.10 64bit machine.

    virtualbox
    WARNING: The character device /dev/vboxdrv does not exist.
    	 Please install the virtualbox-ose-dkms package and the appropriate
    	 headers, most likely linux-headers-generic.
    
    	 You will not be able to start VMs until this problem is fixed.

EDIT:

I have both the latest `linux-headers-generic` and `virtualbox-ose-dkms` packages

How to correct virtualbox installation

Here is how the error output is if I run <code>virtualbox</code> from the terminal. How to correct it? I am on a Ubuntu 12.10 64bit machine.
<pre><code class="hljs language-kotlin">virtualbox
WARNING: The character device /dev/vboxdrv does not exist.
	 Please install the virtualbox-ose-dkms package and the appropriate
	 headers, most likely linux-headers-generic.

	 You will not be able to start VMs until this problem is fixed.
</code></pre>
EDIT:
I have both the latest <code>linux-headers-generic</code> and <code>virtualbox-ose-dkms</code> packages

In the windows environment you will have .m2 folder in C:\Users\user_name location and you will copy your settings.xml file to it in order to setup your proxy settings and nexus repository locations and etc.

So What I have to done on Ubuntu environment to get similar setup after installing maven on it. 

.m2 , settings.xml in Ubuntu

Is it possible in Linux command line to have a command repeat every *n* seconds?

Say, I have an import running, and I am doing

    ls -l

to check if the file size is increasing. I would like to have a command to have this repeat automatically.

Repeat command automatically in Linux

I used the following command to convert and merge all the `jpg` files in a directory to a single pdf file.

    convert *.jpg file.pdf

The files in the directory are numbered from `1.jpg` to `123.jpg`. The convertion went fine but after converting the pages were all mixed up. I wanted the pdf to have pages from `1.jpg` to `123.jpg` in the same order as they are named. I tried with the following command as well:

    cd 1 
    FILES=$( find . -type f -name &quot;*jpg&quot; | cut -d/ -f 2)
    mkdir temp &amp;&amp; cd temp 
    for file in $FILES; do 
        BASE=$(echo $file | sed &#39;s/.jpg//g&#39;);
        convert ../$BASE.jpg $BASE.pdf; 
        done &amp;&amp; 
    pdftk *pdf cat output ../1.pdf &amp;&amp; 
    cd .. 
    rm -rf temp

But still no luck. Operating platform Linux.

Merge multiple jpg into single pdf in Linux

My Ubuntu computer had crashed, and when I restarted it MongoDB wasn&#39;t working. I tried the following commands, and got the following output:

    $ mongo
    Error: couldn&#39;t connect to server 127.0.0.1:27017 src/mongo/shell/mongo.js:91
    exception: connect failed

    $ service mongodb status
    mongodb stop/waiting

    $ service mongodb restart
    stop: Unknown instance: 
    start: Rejected send message, 1 matched rules; type=&quot;method_call&quot;,
           sender=&quot;:1.57&quot; (uid=1000 pid=2227 comm=&quot;start mongodb &quot;)
           interface=&quot;com.ubuntu.Upstart0_6.Job&quot; member=&quot;Start&quot; error name=&quot;(unset)&quot;
           requested_reply=&quot;0&quot;
           destination=&quot;com.ubuntu.Upstart&quot; (uid=0 pid=1 comm=&quot;/sbin/init&quot;)

    $ tail /var/log/mongodb/mongodb.log
    [initandlisten] exception in initAndListen: 12596 old lock file, terminating
    dbexit: 
    [initandlisten] shutdown: going to close listening sockets...
    [initandlisten] shutdown: going to flush diaglog...
    [initandlisten] shutdown: going to close sockets...
    [initandlisten] shutdown: waiting for fs preallocator...
    [initandlisten] shutdown: closing all files...
    [initandlisten] closeAllFiles() finished
    dbexit: really exiting now


(Output reformatted to match website layout.)

What happened? How can I fix it?

MongoDB won&#39;t start after server crash

About a year ago I asked about [header dependencies in CMake][1].

I realized recently that the issue seemed to be that CMake considered those header files to be *external* to the project. At least, when generating a Code::Blocks project the header files do not appear within the project (the source files do). It therefore seems to me that CMake consider those headers to be *external* to the project, and does not track them in the depends.

A quick search in the CMake tutorial only pointed to `include_directories` which does not seem to do what I wish...

What is the proper way to signal to CMake that a particular directory contains headers to be included, and that those headers should be tracked by the generated Makefile?

  [1]: https://stackoverflow.com/questions/7461000/handling-header-files-dependencies-with-cmake




How to properly add include directories with CMake

I tried to set up an virtual machine on Ubuntu 12.10.I installed Oracle Vm VirtualBox Manager.
Then, i followed the steps and i choose .iso file from settings&gt;storage.Then clicked live cd/dvd option.Then OK,when i clicked to start button i get such an error :

     Kernel driver not installed (rc=-1908)

     The VirtualBox Linux kernel driver (vboxdrv) is either not loaded or there is a                   
     permissionproblem with /dev/vboxdrv. Please reinstall the kernel module by 
     executing
 
     &#39;/etc/init.d/vboxdrv setup&#39;

     as root. If it is available in your distribution, you should install the DKMS package                               
     first. This package keeps track of Linux kernel changes and recompiles the vboxdrv  
     kernel module if necessary.

I reinstalled program and rebooted pc, but not worked.Also, updated kernel driver but not worked.What can be done to solve it ?

VirtualBox error : kernel driver not installed(rc=-1908)

How do I delete a VirtualBox machine in the GURU_MEDITATION error state?  Is it enough just to delete the directory while VirtualBox is not running?

EDIT: After posting, I deleted the entire directory that &quot;Show in File Manager&quot; navigates to.

It looks like:

![Screenshot of Virtualbox Guru Meditation][1]

Note that there is no power off, and even remove is greyed out.  I believe this is the exact same as it looked even before I deleted the directory.

EDIT 2: I tried the command line poweroff after deleting the files.  It hangs:

&gt; vboxmanage controlvm wmf-vagrant_1354733432 poweroff 0%...10%...20%...

EDIT 3: It also fails to unregister it from the command-line:

&gt; VBoxManage unregistervm wmf-vagrant_1354733432 --delete VBoxManage:
&gt; error: Cannot unregister the machine &#39;wmf-vagrant_1354733432&#39; while it
&gt; is locked VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE
&gt; (0x80bb0007), component Machine, interface IMachine, callee
&gt; nsISupports Context: &quot;Unregister(fDelete ?
&gt; (CleanupMode_T)CleanupMode_DetachAllReturnHardDisksOnly :
&gt; (CleanupMode_T)CleanupMode_DetachAllReturnNone,
&gt; ComSafeArrayAsOutParam(aMedia))&quot; at line 160 of file
&gt; VBoxManageMisc.cpp


  [1]: http://i.stack.imgur.com/gU1mU.png

How do I delete a virtualbox machine in the GURU_MEDITATION error state?

I had to delete my virtual box .vhd files.
I&#39;m now trying to restore them from another machine but getting:

    Virtual Box UUID {07c3.........} does not match the value {2c1b...} 
    stored in the media registry (&#39;/home/durrantm/.VirtualBox/VirtualBox.xml&#39;)

How to overcome?

Virtual Box UUID {07c3.........} does not match the value {2c1b...} stored in the media registry

Whenever I have Virtualbox running, I cannot start an Android emulator image (and vice versa). The error message in the AVD manager is

    ioctl(KVM_CREATE_VM) failed: Device or resource busy
    ko:failed to initialize KVM

How can I make both run at the same time?

That is a Ubuntu 64 bit, all involved software is of the latest released version.


Android emulator and virtualbox cannot run at same time

I have installed Genymotion for Android in one machine (windows PC) and downloaded a Nexus virtual device. How can I copy the virtual device to another development machine?

or do I have to download again for each dev machine?

Genymotion is storing the virtual devices in {users folder}\VirtualBox Vms


How can this virtual box can be moved to another machine and loaded into Genymotion?

How to copy virtual devices downloaded by Genymotion to another machine?

I&#39;m trying to install a package on a machine with no Internet connection. What I want to do is download all the packages and dependences on a machine WITH an Internet connection and then sneaker-net everything to the offline computer.

I&#39;ve been playing with the `apt-get` and `apt-cache` but I haven&#39;t figured out a quick and easy way to download the package and dependencies in one swoop to a directory of my choosing. How would I do this? Am I going about this problem correctly?
How would you install offline packages that have a lot of dependencies?

 

How to download all dependencies and packages to directory

I have installed OpenCV using the instructions in https://help.ubuntu.com/community/OpenCV

    $ sudo su
    $ sudo apt-get install build-essential
    $ sudo apt-get install libavformat-dev
    $ sudo apt-get install ffmpeg
    $ sudo apt-get install libcv2.3 libcvaux2.3 libhighgui2.3 python-opencv opencv-doc libcv-dev libcvaux-dev libhighgui-dev

now when i execute &quot;pkg-config --cflags --libs opencv&quot; i get this error:

    Package opencv was not found in the pkg-config search path.
    Perhaps you should add the directory containing `opencv.pc&#39;
    to the PKG_CONFIG_PATH environment variable
    No package &#39;opencv&#39; found

how can I resolve this problem?

**-------UPDATE-------**

OK, I figured out how to solve the problem...

I made a file named &quot;opencv.pc&quot; and copied it to &quot;/usr/local/lib/pkgconfig&quot;
Then i added these two lines to &quot;.bashrc&quot;:

    PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/usr/local/lib/pkgconfig
    export PKG_CONFIG_PATH

that&#39;s it! everything is OK now.

the contents of the file are:

    prefix=/usr
    exec_prefix=${prefix}
    includedir=${prefix}/include
    libdir=${exec_prefix}/lib
    
    Name: opencv
    Description: The opencv library
    Version: 2.x.x
    Cflags: -I${includedir}/opencv -I${includedir}/opencv2
    Libs: -L${libdir} -lopencv_calib3d -lopencv_imgproc -lopencv_contrib -lopencv_legacy -lopencv_core -lopencv_ml -lopencv_features2d -lopencv_objdetect -lopencv_flann -lopencv_video -lopencv_highgui

**UPDATE - 2014**



it seems that the ubuntu community has completed the documentation on installing openCV, all you have to do now is to download the installation script from https://github.com/jayrambhia/Install-OpenCV/blob/master/Ubuntu/opencv_latest.sh and execute it.

Package opencv was not found in the pkg-config search path

Installing Oracle Java 7 in Debian via  apt-get repository doesn&#39;t seems to work. 

    apt-get install oracle-java7-installer

Look like `apt-get` does not recognize `oracle-java7-installer`.

Installing Java 7 (Oracle) in Debian via apt-get

Try:

    sudo apt-get install maven

If it works for you ignore the rest of this post.

## Intro
I started setting up my Ubuntu 12.10 on April 2013 and the normal  `sudo apt-get install maven` was not working for maven 3 back then. 

The **manual installation** in this post is useful if you like to dig in deeper to your ubuntu kernel in regards with apt-get and where it finds the list of applications that are available for installation on Ubuntu
. It can also be potentially useful for more recent releases of Ubuntu like **Ubuntu 15.04**, etc. if you face the same problem as I did back then with Ubuntu 12.10. 
 
## Automatic Installation via apt-get:
Checkout the **manual installation** if your current ubuntu can not install maven via common &#39;apt-get install maven&#39;.
    
    sudo apt-get update
    sudo apt-get install maven

Make sure to remove maven 2 if your ubuntu is not fresh or if you were using maven 2 before:

    sudo apt-get remove maven2


##Manual Installation via apt-get by adding maven 3 repository (Ubuntu 14.04 check out update 1):
This can be useful if your ubuntu apt-get repositories list is not up to date.
   
Maven 3 was required to set up the system and as it turns out most of the documents out there are referring to how to install Maven to Ubuntu version 12.04 or before. Best document I found was:

[killertilapia&#39;s blog][1]

The whole process I came up with is as follows:

1. `sudo -H gedit /etc/apt/sources.list`
2. Add the following line the `sources.list` file:

 &gt; deb http://ppa.launchpad.net/natecarlson/maven3/ubuntu precise main 

 &gt;deb-src http://ppa.launchpad.net/natecarlson/maven3/ubuntu precise main

3. `sudo apt-get update &amp;&amp; sudo apt-get install maven3`
4. `sudo ln -s /usr/share/maven3/bin/mvn /usr/bin/mvn`

&gt; Caution 1: command &quot;sudo apt-add-repository ppa:natecarlson/maven3&quot; did not work on my  Ubuntu and had to run `sudo apt-add-repository -rm ppa:natecarlson/maven3` to get my apt-get to work again.

&gt; Caution 2: thanks to David, you need to remove your existing symbolic link to previous versions of maven before running step 4.

##OS X Installation
I decided to add OS X installation in case you use multiple environments for your dev: [See the source stackoverflow thread for more details][2].

Install [Homebrew][3] that is the equavalent of `apt-get`, then install Maven using:

    brew install maven

## **Update 1**: **Installation for Ubunutu 14.04**

Haven&#39;t tried this myself but I am confident this should work without security warnings:

    sudo apt-get purge maven maven2 maven3
    sudo apt-add-repository ppa:andrei-pozolotin/maven3
    sudo apt-get update
    sudo apt-get install maven3

**Note**: source [here][4], many thanks and +1s to @rendybjunior, @Dominic_Bartl, and @FunThomas424242 


  [1]: http://killertilapia.blogspot.com.au/2012/10/installing-maven-3-in-ubuntu-1204.html
  [2]: https://stackoverflow.com/questions/8826881/maven-install-on-mac-os-x
  [3]: http://brew.sh/
  [4]: https://launchpad.net/~andrei-pozolotin/+archive/ubuntu/maven3


How to install Maven 3 on Ubuntu 18.04/17.04/16.10/16.04 LTS/15.10/15.04/14.10/14.04 LTS/13.10/13.04 by using apt-get?

I want to install ruby **2.0** using

    sudo apt-get install ruby2.0

But there isn&#39;t available package for ruby2.0

I want to install it using **apt-get install** the same like ruby 1.9.1

Any suggestions?

Content Type	Original Author	Original Content on Stackoverflow
Question	footy	View Question on Stackoverflow
Solution 1 - Ubuntu	Mike Ruelle	View Answer on Stackoverflow
Solution 2 - Ubuntu	AlexD	View Answer on Stackoverflow
Solution 3 - Ubuntu	ndemou	View Answer on Stackoverflow

How to correct virtualbox installation

Ubuntu Problem Overview

Ubuntu Solutions

Solution 1 - Ubuntu

Solution 2 - Ubuntu

Solution 3 - Ubuntu

How to change the default order pages in Jekyll?

First element of an array with condition

Attributions