In the end it happened that I was using Ubuntu 14.04 but following instructions for Ubuntu 16.04.

After finding and following the correct instructions it had been solved.

Instructions followed:
16.04: https://www.digitalocean.com/community/tutorials/how-to-install-r-on-ubuntu-16-04-2
14.04: https://www.digitalocean.com/community/tutorials/how-to-set-up-r-on-ubuntu-14-04


Ubuntu Touch .... how do you change the wallpaper?

System Settings --> Background (In the personal category)

By default only one image is installed, so you will have to click on custom --> add image


Can NFS Shares mount automatically between two computers?

Deep inside a question about running a script depending on network status, is this little gem

  1. Introduction

  autofs is a program for automatically mounting directories on an as-needed basis. Auto-mounts are mounted only as they are accessed, and are unmounted after a period of inactivity. Because of this, automounting NFS/Samba shares conserves bandwidth and offers better overall performance compared to static mounts via fstab.

sudo apt-get install autofs

  4.1. Edit /etc/auto.master

  The following step creates a mount point at /nfs and configures it according to the settings specified in /etc/auto.nfs (which we will create in the next step).

  Type the following into a terminal:

  sudo nano /etc/auto.master

  Add the following line at the end of /etc/auto.master:

  /nfs   /etc/auto.nfs

  4.2. Create /etc/auto.nfs

  Now we will create the file which contains our automounter map:

  $ sudo nano /etc/auto.nfs

  This file should contain a separate line for each NFS share. The
  format for a line is {mount point} [{mount options}] {location}. If
  you have previously configured static mounts in /etc/fstab, it may be
  helpful to refer to those. Remember, the mount points specified here
  will be relative to the mount point given in /etc/auto.master.

  The following line is for shares using older versions of NFS (prior to
  version 4):

server   server:/

  This creates a new mount point at /nfs/server/ and mounts the NFS root
  directory exported by the machine whose host-name is server.

  4.2.1. NFSv4

  If your NFS shares use NFSv4, you need to tell autofs about that. In
  such a case, the above line would appear as follows:

server   -fstype=nfs4   server:/

  The client needs the same changes to /etc/default/nfs-common to
  connect to an NFSv4 server.

In /etc/default/nfs-common we set:

NEED_IDMAPD=yes
NEED_GSSD=no # no is default

  4.3. Unmount static mounts and edit /etc/fstab

  If you have previously configured the NFS shares as static mounts, now
  is the time to unmount them.

$ sudo umount /server

  Next, remove (or comment out) their respective entries in /etc/fstab.

#server:/ /server/ nfs defaults 0 0

  4.4. Reload /etc/init.d/autofs

  After entering your changes, run the following command to reload
  autofs:

$ sudo reload autofs

  If working on an older ubuntu version, and that does not work try:

$ sudo /etc/init.d/autofs reload

  If working in Natty, and that does not work try:

$ sudo /etc/init.d/autofs restart

  4.5. Make sure it works

  In order to access the share and verify that it is working properly,
  enter the following into a shell:

$ ls /nfs/server

  If you see your NFS share listed, congratulations! You have a
  functioning NFS mount via autofs! If you want to learn some more
  advanced information, keep reading.


Oracle installation script execution privileges: "oracle is not in the sudoers file"

Although I do not have experience in Oracle installation, the error message makes me think, this might work:

sudo adduser oracle admin

This will add the user 'oracle' to the admin group, and the 'admin' group is in the sudoers file by default.

Edit: you need to run this command as the very first user of your system (the one you had to name during install), or as a root (in this case you do not need the sudo part).


Folder/Directory Navigation (Ubuntu 14.04 TLS)

Check whether you are logged in using root privileged user. also use the command given below for searching the file name you are saving in the directory.

  find . -name "file_name.ext"

also if not able to find. update dba nd check using locate command

updatedb as root,
 then locate file_name.extfile


Cannot I upgrade 18.10 to 19.10 without a total uninstall + a new install?

Ubuntu only supports upgrades from one release to the next, and also from one LTS (Long Term Support) to the next LTS. In addition, upgrades are only supported between releases that are still supported. So an 18.10 should have been updated to a 19.04 while it was still supported. Because your release is EOL, there will and cannot be an easy upgrade.

Yet, "easy" is relative. In many cases, a fresh install is by far the easiest way, and is generally recommended over an upgrade.

A fresh installation goes fast nowadays: in less than 20 minutes, you have a brand new operating system. There are several advantages to a fresh install:
It involves a thorough cleanup of your system. Programs you forgot were there, will be removed
Your system is freshly configures according to the most recent insights of the Ubuntu developpers. In contrast, upgrades may perpetuate old configurations instead of implementing newer, better approaches.
Accordingly, you are less likely to bump into issues that may be related to old configuration laying around.


Google chrome closes tab when trying to open extensions settings

I was hoping there was a known add-on to remove but I guess not.  What did work to fix this was the typical uninstall/delete old config files/reinstall

sudo apt-get purge google-chrome-stable
rm -rf ~/.config/google-chrome
#download and reinstall


I've installed Ubuntu/Kubuntu and Linux Mint in Asus x401a. All of them doesn't start after installation. You must boot from Live USB, install and run boot-repair. It makes grub to work with UEFI BIOS. Aafter that, system works well. I only have trouble with brightness adjusting (Fn+F5/F6).


Firstly, your question is very incomplete. Always remember to describe in detail what you have tried and what happened, along with any other info that you think may be necessary, while asking a question.

Looking at your tags and the message, it looks like your wordpress install is not able to accept file uploads.

This is a linux file system permissions issue. Check the permissions of the folder in the error message and all its parents. They should be writable by the user that apache is running as.

Assuming sane defaults, the user would be www-data. In that case,

sudo chown -R www-data /srv/www/wp-uploads
sudo chmod -R u+w /srv/www/wp-uploads

should do the trick.

Please verify your configuration, since improper usage of sudo, chmod, or chown can be dangerous, even more so when used together.

EDIT:

I totally forgot that this can be a improper wordpress configuration. It is entirely possible that you have chosen the wrong directory for file uploads in wordpress. In which case, this other answer is the one you should be looking at.

You can leave the current configuration as-is, in which case all uploads go to /srv/www/wp-uploads or change the uploads directory to a better* value like wp-content/uploads, copy over all files in /srv/www/wp-uploads and delete the latter.

*better because the uploads live inside the wordpress install directory, instead of web root. It is also a common practice.


This(mysql dev download site) or this(mirror site) are the links to download the mysql-6.0.11-alpha-linux-i686-glibc23.tar.gz package. Here are the installation instructions. Though it's not recommended as it's a pre-release version.

As the instruction suggests you have to completely remove the version installed with apt-get in Ubuntu to make a new installation from source.


Someone say it is a NAT type problem.
Others a CORS cross origin request problem.
My view: something in the javascript engine of Omegle that windows accept but debian (and omegle) not.
In my case 90% of stranger camera are greyed out with the rolling icon, but I can see some strangers.
Consider also that Omegle runs (and could call) on different servers.


What is the maximum virtual memory available on Ubuntu (32 and 64 bit)

The limited RAM problem is a problem that affects all OS's. The theoretical limit of RAM is caused by the limit of adresses. With 32bit technology, the effective limit is about 3,4 GB.

The RAM of 64bit systems is for the moment not limited by such a number, but much more by the lack of possibility to build machines with that much RAM. Wikipedia says, the limit is 16 Exabyte.

Hope this helped.


I have a Thinkpad W520 with both intel and nvidia graphics (via nvidia optimus). I very, very, rarely use the nvidia graphics card, and I think that if I were to buy it again, I would skip the extra card because of the extra hassle it brings.

The intel card is perfectly adequate for web browsing, programming, and even some light 3D things like the occasional google earth adventure. If you were to get a linux-optimized laptop with an nvidia card like the bonobo extreme, I would imagine that it would always use the nvidia card, which would severely cut battery life. Most of the time, I completely turn off my nvidia card to save power.

If you are thinking about getting a laptop designed for windows with nvidia optimus, be prepared to learn much more than you want to about the graphics systems. Since nvidia and the open source graphics community haven't been fully cooperating, getting things like extra monitors to work with optimus is very difficult on some models.

I am not aware of any programs running on my machine that use the GPU for non-graphics processing, except for research codes that I have occasionally been involved with.


I'm also learning Qt and tried to find a way to use Unity API in Qt , I could only use Dbus API , but no luck with Quicklist since it needs a DbusMenu and I do not know how to implement that (still learning :) ).

This is the example I created for my self and I hope it's useful for others .
Maybe Unity devs can help to correct / fix / add new code (quicklist) to it :)

/*
    Unity Launcher Dbus API exmable for Qt
    foxoman [gplus.to/foxoman][foxoman.u@gmail.com]

    https://wiki.ubuntu.com/Unity/LauncherAPI#Low_level_DBus_API:_com.canonical.Unity.LauncherEntry

    First step : add this line to your Qt project file .pro
     QT       += dbus
*/

/* I will run this example as Qt console apps */
#include <QtCore/QCoreApplication>

/* Include Qt Dbus required */
#include <QtDBus>

// Qt Main Method
int main(int argc, char *argv[])
{

    /* Qt console Main Loop [ in GUI application the Main loop is QApplication ]
        Unity API need Main Loop to run */
    QCoreApplication a(argc, argv);

    /* Create Qt Dbus Signal to send Dbus Message to unity Dbus API
        signal com.canonical.Unity.LauncherEntry.Update (in s app_uri, in a{sv} properties)
    */
    QDBusMessage signal = QDBusMessage::createSignal(
     "/", /* Path */
     "com.canonical.Unity.LauncherEntry", /* Unity DBus Interface */
     "Update"); /* Update Signal */

    /* app_uri
       Desktop ID ex: firefox -> need to be pined in the launcher to see the effect
    */
    signal << "application://firefox.desktop";

    /* properties : A map of strings to variants with the properties to set on the launcher icon */
    QVariantMap setProperty;

    /* A number to display on the launcher icon */
    setProperty.insert("count", qint64(80));

    /* show count */
    setProperty.insert("count-visible", true);

    /* progress bar count must be float between 0 and 1 (mean from 0.00 to 0.100)*/
    setProperty.insert("progress", double(0.80));

    /* show progress bar */
    setProperty.insert("progress-visible", true);

    /* Tells the launcher to get the users attention  */
    setProperty.insert("urgent",true);

    /* Pack the properties Map to the signal */
    signal << setProperty;

    /* Send the signal */
    QDBusConnection::sessionBus().send(signal);

    return a.exec();
}

download the example here
http://ubuntuone.com/1SLDPcN9OhrU6LD1wgDs3r


I cant access my files after i installed nautilus. Can anybody help?

sudo apt-get install ppa-purge && sudo ppa-purge ppa:gnome3-team/gnome3 fixed the problem... it downgraded it and everything seems to be working now... thank you everyone for your help... sorry im kind of a pain in everyone rear end :D love you ubuntu users :D lol


Hybrid Graphics on Windows 7/Ubuntu 12.04 Dual Boot

To be honest, I think your problem is just related with your configurations. As far as I know, if you installed W7 with one HDD mode in the BIOS, you cannot change it back to the other mode, b/c Windows won't recognize those changes on the SATA controller.

Why I said that? Because I had a similar problem with an Acer laptop.

Probably there is another option, but the way I solve it was by re-installing everything again, but this time be sure the SATA mode is the "compatible" instead of "enhanced". Install w7 again and it should work properly under both, W7 and Ubuntu.

I know it is a brute solution, but it was the only that really works for me.


For those that find this later, it turned out that upgrading the kernel to 3.19 fixed everything. I upgraded, rebooted and the disk mounted on boot without errors. BTRFS check came back OK, as did the scrub.


how do you determine which partion in dual boot pc is for ubuntu?

On the link you provided, you can see the label "Windows" on /dev/sda3, and the partition is formatted as NTFS, which are good indicators of windows being on this partition.

On the other hand, your Ubuntu system partition has the mount point "/" and is ext4 formatted, therefore is /dev/sda6.

You can then assume Windows is on sda3 and Linux on sda6.

As you Windows partition has only 55GB used over the 855GB available, you should be able to downsize it safely using Gparted, and give more room to you Ubuntu.


Xubuntu - Move to the workspace instead moving the app to the workspace

Try this: Settings → Window Manager Tweaks → Focus → When a window raises itself: → Switch to window's workspace.


xrandr: can't add new mode with Nvidia driver

You can try disper with option -r

disper: disper on launchpad

See disper -h

It's a command line tool focused on NVIDIA-drivers, because they don't support xrandr.


scp error: yntax error near unexpected token `newline'

Sounds like a Windows end-of-line problem. dos2unix will fix your problem. From man dos2unix:

   In DOS/Windows text files a line break, also known as newline, is a combination of two characters: a Carriage Return (CR) followed by a Line Feed (LF). In Unix text
   files a line break is a single character: the Line Feed (LF). In Mac text files, prior to Mac OS X, a line break was single Carriage Return (CR) character. Nowadays
   Mac OS uses Unix style (LF) line breaks.


How to fix a not booting Ubuntu setup with encrypted root disk?

All the default hacks and fixes are putting you on a good track, however none of them was complete. This was the solution in my case:

Make sure the /etc/crypttab file is set up correctly. All entries have to refer to existing partitions. There should be
at least one entry named "root", this is the root / entry. This was
crucial for me - and nobody mentioned it so far!
This entry should be referred to in the /etc/fstab with /dev/mapper/root. Check
that the UUIDs are correctly set up
Now run update-initramfs -u
which udpates only your most recent kernel. If a cryptsetup warning
pops up, you failed on the previous steps. Review all files and try
figure out the problem
Run update-grub to fix any remaining grub issues
Now check the /boot/grub/grub.cfg. Go search for the first menuentry which is the one that will be booted.
The search
part should contain the UUID of the boot partition (unencrypted!).
The linux part should have something saying that
root=/dev/mapper/root or pointing to the UUID of the unencrypted volume (in my setup the btrfs volume)
Try to boot. If the lvm errors still pop up, silence them as mentioned in this answer

One last advice: Care for any little warning popping up. Usually they are meaningless, in this case they are very important.

Good luck!


You probably want to remove the /boot/.Trash-0 directory for starters.

To see how much space is being used by /boot and the sub-directories, use: du /boot -h

752K    /boot/extlinux/themes/debian-wheezy
756K    /boot/extlinux/themes
832K    /boot/extlinux
2.5M    /boot/grub/i386-pc
20K     /boot/grub/locale
2.3M    /boot/grub/fonts
7.2M    /boot/grub
565M    /boot

The listing above is a plain vanilla /boot directory listing. You obviously have files / sub-directories in yours which should not be there under normal circumstances.

Compare this listing to your own and you should be able to quickly spot directories that do not belong. Note that my /boot main directory is very large because I have 12 kernels installed instead of the normal average of 2.


Can you see the option for your drive?, if you can, then try moving your drive data on a windows pc, and format your drive as ext-2 format on ubuntu


What's the difference between multiverse, universe, restricted and main?

From the Ubuntu documentation:

  The repository components are:

  Main - Officially supported software.
  Restricted - Supported software that is not available under a completely free license.
  Universe - Community maintained software, i.e. not officially supported software.
  Multiverse - Software that is not free.

For example:

The Ubuntu Desktop team manages the gnome-terminal package, it is officially supported and in the main repository.
bcmwl-kernel-source (the Broadcom wireless driver) is in restricted, since it is a supported, but proprietary, driver.
Community written software that is not officially supported (for example, the game supertuxkart) is in the universe repository.
Packages like ubuntu-restricted-extras (which contains proprietary codecs that allow you to play media files, including flash player) are in the multiverse repository because they are not free and their restrictive licenses prevent inclusion in the default package set.

From Wikipedia:-


Try disabling Compiz and run WoW again.

You can do that simply by choosing on your login screen "classic gnome desktop" without effects, or use the compiz settings manager to turn off compiz.

That will do the trick. Hope this helps. For the HOOOOOOORDE!!!!


Is there a GUI for the tool fwupd (firmware updater) in Ubuntu GNOME?

In the Software Center there is a tool (as deb package from Ubuntu 20.04 onwards, in the universe repository* and snap):
GNOME Firmware (gnome-firmware)
GTK front end for fwupd. It can update, reinstall and downgrade firmware on devices supported by fwupd.

To install it from the command line (Terminal):
For the deb package (Ubuntu 20.04 and newer): sudo apt install gnome-firmware
For the snap app: sudo snap install gnome-firmware
There is a also flatpak version.

It seems that there is still room for improvement of the app, though. Therefore it could be still better to update the firmware from the command line.

For some devices, firmware updates are directly listed in GNOME Software.

*Thank you N0rbert for the hint!


How do I disable vsync in CCSM and Catalyst Control Center?


Installing gcc in Ubuntu 18.04.1 on VirtualBox

Before attempting to install gcc or any other program on a new installation, you should update the packages list first:

sudo apt update

Then install the programs you desire the usual way. (sudo apt install <package-name>)


Linux adobe flash player youtube videos sound distorted

I wish I could post this as a comment but apparently I don't have enough reputation.  In any event, it seems to me like there is a data bottleneck somewhere.  So, check to see that you have sufficient internet speeds for your video quality (try scaling it back from 1080p as most internet connections are too slow, and will cause a "pixel" image accompanied with distorted audio), or it could be the audio card on your motherboard is not compatible with the new flash player audio output.  However, the latter is less likely. If i was you, I would check my hardware to make sure the speed is sufficient for the video quality, and if you are using an older computer, try setting the video settings to the lowest possible quality.  Let me know if it helps at all.


Go to Canon USA's website.
At top right, click on the red colored Drivers and Downloads.
Under Enter a Model, type Maxify MB2320.
Select Drivers.
Select IJ Printer Driver Ver. 5.00 for Linux (debian Packagearchive)
Wait for the download to finish.
Select ScanGear MP Ver. 3.00 for Linux (debian Packagearchive).
Wait for the download to finish.
Highlight the downloaded file. Right click and extract in Downloads.
In a terminal (press Ctrl+Alt+T), run the following commands:

cd ~/Downloads
./scangearmp2-3.00-1-deb

If questions are asked, answer them.
Do the same with the printer file.


I accidentally uninstalled java and now I can't use it

You used jdk instead of jre. To install 8 version use the next command:

sudo apt install openjdk-8-jre

After this, you could see:

$ whereis java
java: /usr/bin/java /etc/java /usr/share/java /usr/lib/jvm/java-11-openjdk-amd64/bin/java

If you know where java binary is you could do:

sudo ln -s /usr/lib/jvm/java-11-openjdk-amd64/bin/java /usr/bin/java

or add to your ~/.profile at the end:

PATH=$PATH:/usr/lib/jvm/java-11-openjdk-amd64/bin

Then reopen terminal and check echo $PATH. But use your java version instead of 11.

  The JRE is the Java Runtime Environment. It is a package of everything
  necessary to run a compiled Java program, including the Java Virtual
  Machine (JVM), the Java Class Library, the java command, and other
  infrastructure. However, it cannot be used to create new programs.

  The JDK is the Java Development Kit, the full-featured SDK for Java.
  It has everything the JRE has, but also the compiler (javac) and tools
  (like javadoc and jdb). It is capable of creating and compiling
  programs.

Reference


What package do I need to install to develop plugins for gedit?

I get the same error as you if I run the plugin code directly without Gedit.

As it is described in the manual you linked, you need to make a .plugin file for your plugin code.
Place your plugin code and the .plugin file into  ~/.local/share/gedit/plugins.
Restart Gedit.
Open Gedit > Edit > Preferences > Plugins and look for your plugin.
Set the checkmark for your plugin.
Your plugin shoud run now using the Gedit code.

To check for errors in your plugin, start gedit from a console.


How to detach modal dialogs from main window? Popup dialogs attached to window title and not movable

I found a much easier solution. Actually you can configure it with the GNOME Tweaks (previously known as "GNOME Tweak Tool"):

Just disable "Attached modal dialogs" under "Windows".


Welcome to the Ubuntu community =)!. Your question gives an interesting perspective on how a windows user views the new world of linux/unix.

When you install (most) applications, they tend to be installed into /usr/bin (on ubuntu), but that is only the binaries. The data files are installed to various other locations, such as /usr/share/applicationnamehere. Libraries generally go into /usr/lib.

Of course all of this information while useful, will probably still not make it seem any more simple to you. The surprising thing you will soon come to notice, is that Ubuntu automatically places your applications in the appropriate folders for you! If you install a ".deb" (installer package) it puts everything where it has to go. You don't get the option to choose where it goes, because the system already has you covered, unlike windows.

The most simple way for you to get applications to the right places, is simply to use the software center, which from your question I'm guessing you have already started to do. You won't have to worry about a "Program Files or no Program Files" issue, Ubuntu's got you covered :)!

Another thing to note, all you need to do to run an application is to type its command. For example, to run the standard text editor, press alt+f2, and type gedit, then press enter. Voila!

You will find Ubuntu, and desktop linux in general, to be a rather intriguing world to work in.


Use the Gnome Tweak Tool, and set "Icons on Desktop" to ON. Believe it or not, that will fix your super key.

Reference: Unity problems after installing GNOME desktop (ubuntu-gnome-desktop)


rename could substitute character in the file name like sed sintax working for you should be (test it before run):

rename s/X/Y *A*X*.csv


How to manage screen sharing settings via cli?

You can do so via the dconf database, either using the gsettings tool or the dconf CLI tool directly
Ex.
gsettings set org.gnome.Vino notify-on-connect false

dconf write /org/gnome/desktop/remote-access/notify-on-connect 'false'

As noted in the manual page,

   Note that gsettings needs a D-Bus session bus connection to write
   changes to the dconf database.

so additional steps (such as launching a dbus session and attaching it to an appropriate session bus) may be necessary if you are trying to do this from outside of a desktop session.


Connect to virtual host from local network

Usually you need to employ a technique called hairpinning to access local servers using their external IP address.

A simpler option might be to add an entry to your /etc/hosts file (on that laptop) that maps www.mysite.com to that local IP address 192.168.1.10, or to let your internal DNS server do that mapping.


Reboot into recovery. Hold Left Shift at boot, select "Other options" then pick the latest recovery mode.
Pick "root shell prompt" when the recovery menu loads.
Run the following:

mount -o remount,rw /
chown -R root: /etc/sudoers{,.d}
chmod -R 440 /etc/sudoers{,.d}
chmod 755 /etc/sudoers.d
reboot


Ubuntu 14.04: setting environment variables

Add the exports to your ~/.profile, that way they are loaded on every login.

Relevant: https://help.ubuntu.com/community/EnvironmentVariables


How do I make Evolution check and notify new emails, without keeping main UI open?

As far as I know this is not possible at the moment. There is already a bug report at launchpad: https://bugs.launchpad.net/ubuntu/+source/evolution-indicator/+bug/508608


ver 12.04 does not install on Proline Notebook

According the this wiki article on ZRAM it is something to do with aiding with SSDs.

Double check your RAM with memtest86+ from the CD to make sure that all is well, chances are you have a bad stick of RAM.


I'd give TestDisk another try; but before doing so, read the documentation more thoroughly, and maybe find an online tutorial or two. (I don't have any specific recommendations.) At this point, the disk is completely unpartitioned, except for the EFI System Partition (ESP), so there's very little to be lost by trying TestDisk again, if your alternative is to re-install everything from scratch. TestDisk can usually recover partitions, so there's a good chance you'll get something back.

That said, aborting a partition resize operation midway is almost never a good thing to do, and whatever partition was being adjusted may be badly damaged. TestDisk might or might not recover it, and even if TestDisk does recover it, it may have filesystem damage -- perhaps enough that you'll have to abandon it and recover files from a backup (or, worse, rely on PhotoRec or something similar; these tools can be hit-or-miss and are likely to leave a huge pile of files through which you must sift). Despite the possibility of such damage, there's also a significant possibility that you'll recover at least some partitions and data.


Grub prompt after upgrade from 10.04 LTS to 12.04 LTS

You need to boot into Ubuntu 12.04 using a live CD & install 'boot-repair'.

You will first need to add the repository using this command:

sudo apt-add-repository ppa:yannubuntu/boot-repair

Then update your index & install boot-repair using

sudo apt-get update && sudo apt-get install boot-repair

Once installed, run the programs "Recommended Repair" option.
This program is nothing short of a lifesaver.

Hope this helps.


Not able to boot from a new kernel after upgrading to ubuntu 14.04

First boot with the old kernel. Open a terminal.

Make sure your system is updated by running:

sudo su; apt-get update; apt-get upgrade

If you are sure you have the newer kernel, run

sudo update-initramfs -u

To create a new initramfs image.
Now update GRUB with the command

sudo update-grub

GRUB should have recognized the newer kernel now. Reboot and you should automatically use it. Just to make sure, run uname -a to see information about the system and the kernel.


Installing Ubuntu 14.04 within windows 7

Yes, that is the way that the WUBI installer works.  Ubuntu will show up as a program in Control Panel that you can uninstall.


To re-configure Grub run sudo update-grub in a terminal. This will check your partitions and will generate a new grub.cfg file. This is also stated at the top of the file you edited:

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

To configure your grub use the file located at /etc/default/grub


Dual Monitor via HDMI, second screen only shows the background on Ubuntu 18.04

OK. So this solved my issue:

$ sudo apt install gnome-control-center
$ gnome-control-center &

Go to Devices → Displays → Display mode and choose the display mode you like.


scrot (screenshot) cron job not executing

Change the line in your crontab to this:

32 8,14,16 * * 1-5 DISPLAY=:0 /usr/bin/scrot /home/johndoe/my.png


After 15.10 upgrade, lost the skype external (logitech camera) mic option

Delete the pulseaudio config and profile files so that pulseaudio is forced to generate new ones:

rm -r ~/.pulse/

restart pulseaudio or your computer afterwards


require_once: failed to open stream: Permission denied(lampp)

I also had similar problem. This was what I did:

chmod my files to 755. You can do this by using (you can try chmoding all files and dirs :p ) but please try step 2 first:

chmod -R 755 your_folder/

Since my classes name began with a small letter which is incorrect

look for this line in your init file:

require_once('libraries/'.$class_name . '.php');

and replace with

require_once 'classes/' . strtolower($class) . '.php';

This got it working for me. I hope I helped :)


Ubuntu v20 does not detect systemd-boot as installed

I would go with it does not have a clue it is installed. If my attempt to find it is anything to go by.
root@zeus-H370M:/home/zeus# apt show systemd-boot
N: Unable to locate package systemd-boot
N: Unable to locate package systemd-boot
E: No packages found
root@zeus-H370M:/home/zeus# apt show grub
Package: grub
State: not a real package (virtual)
N: Can't select candidate version from package grub as it has no candidate
N: Can't select versions from package 'grub' as it is purely virtual
N: No packages found
root@zeus-H370M:/home/zeus# apt show grub-pc
Package: grub-pc
Version: 2.04-1ubuntu26.9
Priority: optional
Section: admin
Source: grub2
Origin: Ubuntu

Without those type of details of how it was installed, is there a conflicts line with grub and lilo mentioned so it prevents them from getting installed. Those are what you need to look for to sort this out. Almost missed this related package, though from the description it is not clear if it supplies the command or not and a file search now I think of that one too.
root@zeus-H370M:/home/zeus# apt-cache search systemd-boot
sicherboot - systemd-boot integration with UEFI secure boot support
systemd-bootchart - boot performance graphing tool

Nope no luck there either, unless this is what you use /usr/lib/systemd/boot/efi/systemd-bootx64.efi.
root@zeus-H370M:/home/zeus# apt-file search systemd-boot
manpages-de: /usr/share/man/de/man7/systemd-boot.7.gz
manpages-de: /usr/share/man/de/man8/systemd-boot-check-no-failures.service.8.gz
systemd: /lib/systemd/system/sysinit.target.wants/systemd-boot-system-token.service
systemd: /lib/systemd/system/systemd-boot-check-no-failures.service
systemd: /lib/systemd/system/systemd-boot-system-token.service
systemd: /lib/systemd/systemd-boot-check-no-failures
systemd: /usr/lib/systemd/boot/efi/systemd-bootx64.efi
systemd: /usr/share/man/man7/systemd-boot.7.gz
systemd: /usr/share/man/man8/systemd-boot-check-no-failures.8.gz
systemd: /usr/share/man/man8/systemd-boot-check-no-failures.service.8.gz
systemd: /usr/share/man/man8/systemd-boot-system-token.service.8.gz
systemd-bootchart: /lib/systemd/system/systemd-bootchart.service
systemd-bootchart: /lib/systemd/systemd-bootchart
systemd-bootchart: /usr/share/doc/systemd-bootchart/README
systemd-bootchart: /usr/share/doc/systemd-bootchart/changelog.Debian.gz
systemd-bootchart: /usr/share/doc/systemd-bootchart/copyright
systemd-bootchart: /usr/share/man/man1/systemd-bootchart.1.gz

So I still go with my initial conclusion, not a clue it is installed.
This was too long for comment and really should be here anyways. I just did an EFI entry for my machine I show all the commands on with the efiboormgr this is why I pointed to that .efi file suspecting you were doing such a thing, loading from efi only. That is not known to the packaging system it has no idea of changes you make to the system unless you tell it. You can do a fake .deb package that does nothing but install itself and has a conflicts line with grub and lilo then those never get installed or as you have done now apparently pin them so low they never get installed when a kernel is updated. Then you do whatever process you need to do to update that efi loading of the new kernel. There is your reason for the actions it took with your install.


How do I save a line in terminal without runninig it?

Press Ctrl+U to "cut" the command you were writing (actually, everything that is before the cursor).

Then, later, press Ctrl+Y to "paste" that command.


Maximum resolution problem when external monitor is connected via KVM Switch

This is a typical case caused by EDID/DDC communication from the connected and shared monitor DID NOT successfully and correctly passed between:
1. Connected systems to KVM switch,
2. or the shared monitor to the KVM switch.

Normally, it is very easy to be solve - If the video sharing is for Sharing DVI monitor, then go for DVI-EDID emulator - let it connected between your shared system and the new DVI monitor.
u
Rex W


UBUNTU 18.04 Server: multiple netplan route-policy rules, but only one works


Why does 11.04 server fail to boot with 'can't find /sbin/init'?

OK, first of all this appears to be a KVM running on Proxmox, right?

/dev/sda1 appears to be a separate boot partition (/boot). You are probably looking to set /dev/sda2 as the target in recovery mode, which should contain /, /sbin, /proc etc. where the problem lies (can't find init).

Based on the segfaults you get, it looks like the root ilesystem on /dev/sda2 may be corrupted. Please run sudo fsck on it; you may have to attach an Ubuntu LiveCD ISO to your KVM and boot from that to be able to do so.

A screenshot of the full text preceding the segmentation fault on boot up (see cutoff portion in first screenshot) might also be helpful.


To install Keryx, download the deb file, and just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, navigate to where the file was downloaded(probably the Downloads folder),run the command(s) below:

sudo dpkg -i <file_name>.deb

Once installed, run the application, and see here and here on how to use.

Now from what I heard from a friend that used Kyrex, and he told me that it has some problems.  I haven't personally used it, since I use Synaptic instead, you may want to take a look at it.


sudo dpkg fails when trying to install wifi driver (on mac)

I suggest that you download the DKMS package* and all dependencies that you don't have on a computer with a working internet connection.

Then, simply put it on a USB drive and plug it into your PC. Run

sudo dpkg -i /path/to/file/dkms_2.2.0.3-1.1ubuntu5_all.deb

and enjoy the WiFi.

Alternatively, plug your Mac into an Ethernet port and download the package that way. You'll get all the dependencies without too much complication.


When using the lsusb command is there a why to get the divice name only?

lsusb | cut -c34-

would show what you need.

$ lsusb
Bus 002 Device 002: ID 8087:8000 Intel Corp.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 003: ID 04f2:b3fd Chicony Electronics Co., Ltd
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
$ lsusb | cut -c34-
Intel Corp.
Linux Foundation 2.0 root hub
Intel Corp.
Linux Foundation 2.0 root hub
Linux Foundation 3.0 root hub
Chicony Electronics Co., Ltd
Linux Foundation 2.0 root hub


No bluetooth applet visible in ubuntu 12.10 with mate desktopk environment!!!

sudo apt-get install mate-bluetooth

I believe its part of the mate-desktop-environment-extra  meta package, which rarely gets mentioned in MATE installation howtos hence why its probabley not in your install.


How to select display to record in RecordMyDesktop

You have no need to set the display to 1 since probably you are running a multi- screen setup on the same X server.

The correct command would be:

recordmydesktop --display=0 --width=1920 --height=1080 --fps=15 --no-sound --delay=10

Reduce the width and the height parameters if that is including your 2nd screen.


/dev/sdal was full
Had to get it by going down through the
grub menu (hold down shift on start up),
selecting Advanced Options,
selecting Recovery mode,
selecting root,
deleted just enough unwanted files allowed me to reboot
and continue from there.


Command 'ruby' not found after successful installation using rbenv on Ubuntu 20.04

I found a way to fix the problem.
First, I deleted every file associated with rbenv and ruby installations.
These are: .rbenv folder in Home directory and the ruby-build folder in /tmp directory.
I then did a fresh re-install using rbenv beginning from step one:
https://github.com/jhu-ep-coursera/fullstack-course1-module1/commit/170f351229887f54f154fba637048520041951b4
The installation was successful as usual, and doing ruby -v this time displayed the installed ruby version:
ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-linux]

I'm not sure what exactly went wrong, though I have some suspicions:

The network was unstable during the previous installs. In fact, the installation failed earlier about three times due to Download failure. Could it be that the unsuccessful installations created some files which affected the later installations?
I checked the /tmp folder directory again after the last installation that worked and I discovered that there was no ruby-build folder (asides the ruby-build log file) unlike the previous installations. Can anyone explain why?
I compared the log files of one of the previous installation that threw an error after running ruby -v and the log file of the last installation that worked.
The output of the previous installation:

/tmp/ruby-build.20201024162152.8685.pHbqqa ~ curl: (56) OpenSSL
SSL_read: Connection reset by peer, errno 104

The log file seems to me that there was network interruption which affected the installation process.
But, why then did the terminal displayed that the installation was successful until I did ruby -v?
Many thanks.


Why I can't get incremented var outside loop on shell script

As @steeldriver pointed me, when I pipe I create a subshell and the var values are not passed to the outer var.

As this link provides

The solution would be something like this:

while [ 1 ]
do
        COUNTER=0
 while read pap
        do
                ret=`cat $pap`
                if [ "a$ret" == "aTimeout" ]
                then
                        echo "do something"
                else
                        arr[$COUNTER]=$pap
                        COUNTER=$(( COUNTER + 1 ))
                fi
                sleep 0.3
                echo $COUNTER
        done < <( ls /tmp/paping* | grep -v pid)
        echo $COUNTER
done

Now my counter is working as expected!


To install lightspark flash in Ubuntu:

Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the commands below.

    sudo add-apt-repository ppa:sparkers/ppa
    sudo apt-get update
    sudo apt-get install lightspark browser-plugin-lightspark

For 13.10

Do this.  Ensure that universe is included in your software resources and, just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command below.

sudo apt-get update
sudo apt-get install browser-plugin-lightspark

You'll need to restart your browser

Also you can check out Ubuntu Packages, to manually install using a .deb file.


Where to make configuration changes to MySQL in Ubuntu 20.04?

The standard practice for MySQL configuration settings is to create a separate file in /etc/mysql/mysql.conf.d/. MySQL will read all .cnf files in that directory alphabetically, so if there are settings you need to configure that may also exist in the default configuration files, you’ll need to give them a file name starting with letter n or “higher”.
Generally what I do with MySQL configurations is keep some defaults in a Git repository that I then copy to a new server as needed. Here are some examples:

File
Purpose

z-replication.cnf
Contains template to set up replication

z-highmemory.cnf
Contains template configured for machines with more than 64GB RAM

z-pi.cnf
Contains template for very low-powered, write-based devices (like Raspberry Pis used for sensors)

… and so on. By doing this, updates to MySQL do not interfere with my settings and vice versa.


What is the most recent MSOffice that can be run under Wine/Playonlinux?

Since the new Wine 2.0 version got released, you can now theoretically run MS Office 2013 with it, according to the announcement on the official WineHQ website:

  The Wine team is proud to announce that the stable release Wine 2.0
  is now available.

  This release represents over a year of development effort and around
  6,600 individual changes. The main highlights are the support for
  Microsoft Office 2013, and the 64-bit support on macOS.

The new Wine is not yet provided through the official Ubuntu repos as far as I know though, so you have to install it from their official Wine PPA:

sudo add-apt-repository ppa:wine/wine-builds
sudo apt-get update
sudo apt-get install winehq-devel

More information about installing Wine 2.0 on Ubuntu may also be found here.

After that, you should be able to install MS Office 2013 on Wine.

Sources:

OMG Ubuntu: "Wine 2.0 Released, Lets You Run Microsoft Office 2013 on Linux"
WineHQ: Wine 2.0 Announcement


You can take the Windows-being-useless issue out of the equation very simply: create a share and mount it on your Linux machine (with smbfs or CIFS). It's fairly simple so I'll leave that between you and the Ubuntu Help Pages.

From there it's fairly simple:

Create a script. Call it something logical, put it somewhere where you won't trip over it or accidentally move it. chmod +x it too.
Get your script to do what you want. I'll assume you mounted your writable Windows share as /mnt/win (mount it under /mnt/ if you don't want it show up in nautilus) and that you want these directories stored in ~/daily-backups/.

#!/bin/bash

SRC="/mnt/win"
OUT="~/daily-backups"
DATE=$(date '+%Y-%m-%d')

NEWDIR="$OUT/$DATE"

# make the new directory for today and cd into it
mkdir -p "$NEWDIR"
cd "$NEWDIR"

cp -R "$SRC/*" . # could use rsync

cron it up. Assuming your script is called ~/daily-backups/do-backups. Type crontab -e and in the editor add a new line like this:

0 22 * * * ~/daily-backups/do-backups

And that will run your script every day at 10pm. Obviously you might want to tune that to a more sentible time but I wouldn't leave it until midnight or the datestamp might get confusing.


How can I get help on terminal commands?

What is a man page?

A man page (short for manual page) is the traditional form of software documentation on a Unix-like OS like Ubuntu. For the vast majority of commands and programs there's a man page which lists its options and explains its usage.

How can I find and view man pages?

Offline in a terminal

Man pages are automatically installed on your system together with the commands they describe. To view and search man pages there's the command man:

man mv

displays the man page of mv while

man -k mv

searches names and short descriptions of all installed man pages for the string mv. POSIX Extended Regular Expressions are allowed and it's a search, so this will also find e.g. git-mv and semver, if you want to search exactly mv use ^mv$ instead.

See What is the difference between `man` and `man (#)`? to read about man page sections. For more information read man's man page. ;)

How can I influence how a man page is displayed?

The default program to display man pages is less. This so-called pager provides a helpful search function, just enter / followed by the search term, e.g.

/--version

and press Enter. This will mark every finding and scroll to the first one. Press N to go to the next finding and ⇧ Shift+N to go to the previous one (see How can I search within a manpage?). For a list of commands press H, to exit less press Q.

Beside less there are other pagers available: pg, most and w3m just to list three. I recommend most: It comes with a very useful coloring of key words making a man page much easier to read and navigate, see for yourself:

To view a man page in a different than your default pager use the -P option, e.g.:

man -P most mv

If you want to change the default pager manpages are displayed with you have two options:

change the default pager solely of man

export MANPAGER=most

To make the change persistent add this command to your ~/.bashrc file.
change the default pager of your whole system

sudo update-alternatives --config pager

Fans can even (ab)use vim as the MANPAGER, see this article written by muru.

Man pages are displayed in the font specified in your terminal emulator settings. If you work with the terminal regularly you might want to change this font; I can only recommend Hack – a typeface designed for source code, see the screenshot above for its beauty.

Offline via GUI

A nice and easy way to display man pages with a simple GUI is the preinstalled yelp program. To start a man page with yelp execute yelp man:PROGRAM or gnome-help man:PROGRAM, e.g.:

yelp man:mv

You can also view man pages with your preferred browser, see How do I make man pages open in a web browser?, e.g. for man mv in firefox:

man -Hfirefox mv

Last but not least you can convert man pages to PDF and view them with your preferred PDF viewer, see: Is there a way to print info/man pages to PDF?

Online

http://manpages.ubuntu.com

You can view the man pages of programs available via the repositories of every currently supported Ubuntu version with the shorthand URL manpg.es/PROGRAM, e.g. http://manpg.es/mv. This opens mv's man page for the latest Ubuntu release, you can choose a different release in the top bar. To search for man pages you can use e.g. http://manpages.ubuntu.com/cgi-bin/search.py?q=mv.

As explained above man can only display man pages of software installed on the system. To view man pages from http://manpages.ubuntu.com using a terminal pager there's dman available in the bikeshed package.

Other sources

When you read documentation from other online sources it's a good idea to keep an eye on the program version. Most programs have a --version option that displays the version of the program in question, e.g.

$ mv --version
mv (GNU coreutils) 8.25

There are a lot of websites which dedicated themselves to make man pages easily available, I'm just going to present the two I like the most:

man7.org comes with useful syntax highlighting, but it features only the last released version of the program
manpag.es hosts man pages of Ubuntu releases long gone EOL

Source not already linked: https://wiki.ubuntuusers.de/man/


For fun I ran Blowfish from the hardinfo tool that's part of the Ubuntu standard distribution.  I assume this is the same benchmark that you are doing your testing with.

My i3-2120 3.30 GHz x 4 CPU says 1642 MHz and gives a score of 3.58.  The test runs in a couple of seconds so it's hardly an exhaustive benchmark and likely does not test using all 4 cores.

My  i7-6700K CPU @ 4.00GHz × 8 CPU tests at 1.08 and says the CPU speed is 800 MHz.

As the results output says, a lower number in the test score indicates a better result.

Both machines are rockets in a real world computing environment.

I'd suggest that there is a problem with hardinfo's Blowfish testing capabilities and not a problem with your CPU upgrade.  Comprehensive, reliable benchmarks will take a while to run, not seconds.

As for the drivers, my machines also show as "unknown".  This fact is likely a red herring in regards to Ubuntu performing as it should with these CPUs.


Prevent Desktop Icons / Shortcuts From Being Deleted & Moved

You can prevent files from being deleted using permissions.
What you need is :

  755 (rwxr-xr-x) The file's owner may read, write, and execute the
  file. All others may read and execute the file. This setting is common
  for programs that are used by all users.

(learn more here, and here)

Command line

Assuming a launcher icon "launcher" in /home/student/Desktop/launcher owned by admin (superuser)

set correct permissions using the following command :

sudo chmod 755 /home/student/Desktop/launcher

You can do that for the folder (and for all files in it) this way :

sudo chmod -R 755 /home/student/Desktop

and neither teacher nor student can delete these icons (files, actually).

Graphically

Right clic on file > Properties > Permissions (take a look here)

owner "admin" access "read and write" (or "create and delete")
group "admin" access "read" (or "access files")
others        access "read" (or "access files")

For the "moving" part of your question, I don't know.


So here we create an fstab entry for the partition:

You need to create the folder for the partition and get the device id. Open a terminal.
The folder can be created via sudo mkdir /media/Data In addition I would make the user the owner and give him the right to read/write: sudo chown [user]:[group] /media/Datasudo chmod +rw /media/Data
Now the fstab entry:

Install libblkid1 to see device specific information: sudo apt-get install libblkid1
Enter sudo blkid and look for the stick. The output could be:/dev/sda2: UUID="32a4b76f-246e-486e-8495-31b8a781fb4c" TYPE="swap"
/dev/sda1: UUID="31f39d50-16fa-4248-b396-0cba7cd6eff2" TYPE="ext4"

Then we create the fstab entry: sudo gedit /etc/fstab and append the line UUID=31f39d50-16fa-4248-b396-0cba7cd6eff2     /media/Data   auto    rw,user,auto    0    0(and afterwards give a empty new line to avoid warnings).

To mount the partition, open a terminal and type mount /media/DataBecause of the entry auto it should be mounted automatically on next boot.


Screen glitching to desktop wallpaper when recording

solved it by disabling "Allow Flipping" in Nvidia Settings


Just fo to System Settings -> Software & Updates -> Additional drivers

and install suggested driver from there.

Or run in terminal

sudo apt-get install fglrx

This is not an Ubuntu way to download video drivers from sites.

But sometimes proprietary drivers have bugs and incompatibilities. If system does not load GUI, you do not have to re-install.

Start console with Ctrl+Alt+F1, login there and run

sudo apt-get purge fglrx*

to revert it.


The click packages are designed to be self-contained apps that are currently only supported on the phone/tablet version of Ubuntu. They cannot specify dependencies on other packages (such as free pascal, which is not included in Ubuntu). Once full convergence is ramped up in Ubuntu though, it should be possible to package more apps such as yours, as click packages.

For now, your best option will likely be to create a PPA for your app on Launchpad, and create Debian (deb) packages for the dependencies, and the app itself.


Yes you may.

"Hewlett-Packard Linux Imaging & Printing (HPLIP) is an HP-developed open-source Linux solution for printing, scanning, and faxing with HP inkjet and LaserJet printers." - source http://hplipopensource.com/node/249


You need to install "Synaptic Package Manager(click here to know how to install
it)"
After installing that software, do as shown in image below
open the software, click on "edit", then click "fix broken packages", then click "Apply" (which you will find it below menu bar)
After this click on this link to know how to install wine 1.7. Follow the method properly, you be fine

Done !


You can toggle wifi and bluetooth by pressing [Fn] + [F3]. This will toggle between all off, bluetooth only, wifi only and both enabled. Give a try.

Good luck!


Rename all files in a folder to consecutive numbers

Assuming you want to follow the shell globbing order while sorting files, you can do:

#!/bin/bash
counter=0
for file in *; do
    [[ -f $file ]] && echo mv -i "$file" $((counter+1)).png && ((counter++))
done

Here looping over all the files in the current directory and renaming sequentially based on order, if you want to deal with only the .png files, use for file in *.png instead. counter variable will keep track of the increments.

This is a dry-run, remove echo to let the actual renaming action take place.

Example:

$ counter=0; for file in *; do [[ -f $file ]] && echo mv -i "$file" $((counter+1)).png && ((counter++)); done
mv -i file.txt 1.png
mv -i foo.sh 2.png
mv -i bar.txt 3.png


How do I add the "atkbd.reset i8042.nomux" parameters to rEFInd?

I got it; as an answer to this question mentions, additional parameters can be added to the first line of /boot/refind_linux.conf


How do I execute commands installed by a snap package?

Directory /snap/bin contains symbolic links to the installed snap applications. Add this directory to your path:

PATH=/snap/bin:$PATH

You should also add this to your ~/.profile or ~/.bashrc file.


How to download Facebook videos from command line?

What version of Ubuntu & youtube-dl are you using?

To make sure you're using the latest youtube-dl available, do the following:

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install youtube-dl

After doing the above in Ubuntu 14.04 Trusty, I got 2018.01.07 version of youtube-dl and was able to download the video in question:

youtube-dl 'https://www.facebook.com/Roscosmos/videos/2032700800317930'
WARNING: Assuming --restrict-filenames since file system encoding cannot encode all characters. Set the LC_ALL environment variable to fix this.
[facebook] 2032700800317930: Downloading webpage
WARNING: Your copy of avconv is outdated and unable to properly mux separate video and audio files, youtube-dl will download single file media. Update avconv to version 10-0 or newer to fix this.
[download] Destination: _-2032700800317930.mp4
[download] 100% of 3.36MiB in 00:01

The video download now fails, however, due to another reason. It will only download a single part of the video, and will not proceed further.

The reason is that youtube-dl uses libav to combine downloaded files, while libav available in the system is outdated – youtube-dl expects version at least 10.0, but the system has 9.2:

dpkg -l | grep libav-tools
ii  libav-tools                       6:9.20-0ubuntu0.14.04.1                    amd64        Multimedia player, server, encoder and transcoder

Weirdly, I could not find any quick way to install latest libav in Ubuntu 14.04.

I guess at this point the only way to make this youtube-dl work would be to build & install libav manually – https://libav.org/download/.

Someone actually stumbled upon a similar issue that required him to figure out how to build libav. Here are the detailed step-by-step instructinos: http://xiemingzhi.github.io/2016/03/25/installing-libav-on-ubuntu-1404-trusty


How to open terminal inside a folder in Nautilus, so that the folder is the current location?

Maybe this is what you're looking for:

sudo apt-get install nautilus-open-terminal

After you'll get a new entry in the contextual menu of nautilus (you probably need to relaunch your session to get it work).


recover deleted files that are still in memory

Yes you can. You need to dump (or use another tool) the whole memory, and then analyse your dump with volatile to recover your files.
You can even recover files in RAM that were used by a process, which was killed, an example here.
If you are in a virtual machine, you do a snapshot instead of the dump, and then use volatile too.
Easier and more classic, if you can stop the activities on your hard drive, you can dump the whole drive and recover the data with R-studio for instance.


When you log in to windows 8, it tries to index some data. After working with your windows for a while, the data will become bigger and bigger and it cause a high and noticeable disk usage.

Ubuntu is not as optimal as windows 8 in resource managing. In addition, there can be a problem with your GPU driver. If you didn't install that, take a tour here. It could help a lot in controlling the temperature.

Don't worry, there is nothing wrong with having a dual boot system.


How can I work out how long I've been an Ubuntu Member for?

If you became an Ubuntu Member through the direct way you can see when, in Launchpad. On memberships page mentions "Member Since"

If you became an Ubuntu Member through the indirect way (ubuntuforums.org), then you can search for your application in UbuntuForums and check the last message.
For example my application is here and the last message from Elfy indicates that I became a member in November 17th 2012. Alternatively, a page exist in Launchpad for Ubuntu Forums Members


Suddenly webcam of my x300 is not working

I have installed libpt-1.10.10-plugins-v4l2 and restarted the machine. Now it is working.


Is Ubuntu-ARM essentially the same as Ubuntu?

Ubuntu is intended to be identical for each architecture (currently amd64, armel, i386, powerpc), although there may be some slight differences in behaviour due to incomplete porting to a given architecture (there currently exists no architecture in the archive with no outstanding porting issues, although most are difficult to notice for most users).

Ubuntu Desktop images produced for ARM have included unity-2d as the primary session rather than unity, mostly because there are very few graphics cards available for common armel platforms that support OpenGL in Ubuntu (and none are bundled with common reference devices).  I understand that work is in progress to port Unity to OpenGL ES, which is more commonly supported by default on reference devices, which should result in a return to shipping identical images for Ubuntu Desktop.

All Ubuntu documentation, guides, processes, etc. should be the same, regardless of architecture (assuming compatibility of underlying hardware), with the result that if you can achieve some network solution with one architecture (e.g. powerpc), you should be able to do so with another (e.g. armel).

When constructing a network solution with multiple architectures, take care that you have parallel installations of packages, rather than sharing binaries directly between machines: while the same package should behave the same regardless of architecture, in the common case, one is unable to execute e.g. amd64 binaries on an armel host.  Packages in the archive have been separately compiled for each architecture to avoid this confusion, so running apt-get install (or otherwise invoking your favourite package manager) will install the correct build of the package.


PlayOnLinux not working with on wxPython 4.1.0 - ImportError: No Module named wxversion, needs to be wx.version instead

Short answer: The problem is related to pyenv, make sure system is first choice in global configuration: pyenv global system or set the python version for the current shell with pyenv shell system. If you use global you only have set it once.
Short explanation: Use pyenv global system (2nd) (3rd)... to ensure that playonlinux finds the right python; where (2nd) and (3rd) are pyenv version numbers for your installed interpreters.
Long explanation: After getting the curtain rolled back with the really helpful posts by @N0bert, I've discovered that in my case the problem is pyenv related.
Specifically, I can resolve my issue by using the pyenv global command and making system first as follows (Note: the command you execute will depend on the versions of python you have installed):
pyenv global system 3.8.3 2.7.18 anaconda3-2019.10

Investigating the problem more, I reviewed the following files:

/usr/share/playonlinux/bash/find_python
/usr/share/playonlinux/python/check_python.py

I made my own copies of these to understand the error better. It turns out the wxversion error is really misleading, the real problem is finding the right python shell to run. playonlinux depends on the system python.
Initially I thought that running the pyenv local system would solve the problem, but because of how pyenv works this was not the case.
To ensure that /usr/share/playonlinux/bash/find_python resolves to the system installed python, you must make sure that pyenv global is set with system as the first choice.
Many thanks to @N0rbert !!


Why no Space on my HardDrive? Storage Summary on login different from df -h output

I would rather use ncdu it has saved me several times from such errors. I noticed over time, that some directories when they contain a lot of files, they report crazy size. This happened to me several times and on different hard drives on different servers.
To get ncdu which stands for no curse disk usage

sudo apt-get install ncdu


How can I ensure I am running the current stock kernel?

Use uname -r to find your running kernel version/variant

For example, 12.04 stock 64-bit returns 3.2.0-29-generic

Note that stock/official kernels only have 2 or 3 digits after the "points", e.g. -29 here.
The mainline/custom kernels have six digits, so the 030300 you are running is NOT a stock kernel
You can update to the latest stock kernel by running sudo apt-get update && sudo apt-get install linux-image-generic or ...generic-pae, depending on what your uname -r output shows you
You can choose kernels at boot from the GRUB menu, just keep Shift pressed down


I use handbrake for all my video conversion.

It is very simple to use, and easy to figure out.

never tried it for merging or splitting video files, so cannot comment on how it handles it.

but looking at this post No sound in .mp4 file converted with x264

dmMediaConverter looks like it will do what you want it to do.


How to toggle easily between the AMD Catalyst driver and the open-source Radeon driver?

I am not sure This is the thing you are looking for or not. But when I was trying to change the source of my graphics drive I did it form the software and updates and then additional drivers.


Can browse internet but can't update Ubuntu 14.04

That sounds a lot like a proxy issue. Check if you are using a proxy to browse the internet (firefox or whatever browser you are using) and replicate the setting to your network proxy sttings of the system. You can also use thr /etc/environment file to setup the proxy by adding a line http_proxy entry . This will equally for for https_proxy and ftp_proxy. Or, if no proxy exist on browser, verify that system isn't using one as well. After changing this do a network restart.


I am not a bumblebee user but my understanding is that bumblebee is using the nvidia proprietary driver which implies that lmsensors will no more handle the temperature of the nvidia gpu. See http://packages.ubuntu.com/trusty/utils/bumblebee-nvidia, it depends on the NVidia proprietary driver.

If I am right, you can read the temperature of the NVidia chip with the command 'nvidia-smi' or a GUI like 'psensor' (to install it: sudo apt-get install psensor).


"Fix Committed" means developers have figured out a working solution to a problem, and have it merged into their development repositories.

The problem will be delivered in updates when the bug is marked "Fix Released" for your Ubuntu version.


Facebook Bangla font Problem in google chrome

The problem might not be version bug as other answer suggesting, since it is still in chrome 29. A more concrete solution could be this.

First Download a standard Bangla font, such as Solaiman Lipi.
Install the font by copying it to either your user specific ~/.fonts folder or for system-wide effect in /usr/share/fonts/truetype folder.
Then close (if it is opened) and open the Google chrome.
Go to Settings, click on Advanced settings, in Website content section, click on the customize fonts button.
In the sans-serif font section, change the font to Solaiman Lipi.

This should solve the problem.

Credit: This page on blogspot

Some alternative fonts:

You could also install lohit bengali font and use it. to install use the command in a terminal:

sudo apt-get install fonts-lohit-beng-bengali

Or you might want to test some of the fonts from omicron-lab site


Moving boot drive from /dev/sda (regular HD drive) to /dev/sdb( SSD)

If you have absolutely nothing to save, or if you want a quick solution and you can just backup your files and restore them, then follow the advice of others and do a fresh install.  Continue reading to help understand a bit more about the normal setup, and benefits, etc.

Otherwise,

The 'boot drive', in Linux, is actually /boot/, not /.  The root of the system, or system root is /, which is mapped to a specific partition.  The boot partition stores the boot-level kernel (initramfs/initcpio), which loads additional modules and functionality from the Linux Kernel that is loaded.

So, when you install your Linux system, you will have / and /boot.  They do not have to be different partitions (with /boot having a lower ID, typically), but we typically break them out and have /boot as a more simple filesystem, such as fat32, and / (system root) as a newer filesystem, such as ext4.

You should be able to see this by looking at the contents of /etc/fstab, or issuing the mount command, with no arguments, to show you the currently mounted filesystems.

Yes, in order to have the fastest boot time, you can place the /boot partition on the SSD, but in reality, only boot time will increase, not overall performance.  By leaving the /boot partition as-is, you can simplify the steps required, or you can choose to move it at higher risk/complication.

By having your / (system root) on the SSD, your entire system will speed up, and might be your primary objective and concern.  This is controlled through kernel parameters, and would be the only adjustment needed if you maintain the /boot partition as-is.

As your system matures, you may even create partitions on the HDD, and mount them on the Linux system (such as /mnt/data) so that you can use lower-cost, slower storage for files that are accessed less frequently.

Again, you'll need to carefully inspect the Windows disk and properly shrink the Windows partition so that the disk has additional space for your /boot and /.  /boot doesn't need to be more than 512MB, while / size will limit your Linux installation total size, unless you add additional partitions as described above.

gparted is available on Ubuntu LiveCD and helps in these processes.

If you boot into Ubuntu using the installation disk, called LiveCD, you can make adjustments to your partitions as descibed.

A hybrid approach would be to install Ubuntu onto the SSD, being careful to not destroy any data/partitions, and then mount the existing partition onto the new system after installation.  For example, after installing Ubuntu onto the SSD, you can mount the old Linux partition, and copy files over as needed, or re-use as the previously discussed /mnt/data partition for extra space.


M620 Blade Servers Not Accepting Ubuntu 16.04 as the new OS

So the EXSi was actually on an SD card on the back of the blades. we were not able to disable it but what we did do is through the system BIOS settings change the order in which the system boots from the hard drive, with Ubuntu, rather than the SD card with EXSi.


Alt+F4 stops working after compiz restart. How to fix?

I believe this is a bug.  Going into CCSM and toggling the Close Window key binding under General Options fixed it for me, but this is obviously not an ideal solution.


Ubuntu does not remember keyboard layout

It is an only one bug I have found so far as well. Here is my temporary fix: Alt+Shift to toggle between Norwegian and Thai keyboards.

sudo setxkbmap -option grp:alt_shift_toggle no,th


Will Unity offer more keyboard configuration?

Many of keybindings you can change in Compiz Config Settings Manager (ccsm command).


Default Bluetooth audio mode set to HSP/HFP instead of A2DP 17.04

I'm running Debian, but the results are about the same from my experience. The only sure fire way I've found to ensure that Linux defaults to A2DP instead of HFP is to connect to a A2DP-only device before connecting to the dual profile device. Connecting to the A2DP-only device sets the default for some reason and then the dual profile device works great in A2DP mode. This is a pretty horrible experience.


how to find exact file without listing folders

The easiest method would be to use locate. It will only show the actual file (and directory):

$ locate Screenshot\ from\ 2013-02-13\ 22\:36\:33.png
/home/rinzwind/Screenshot from 2013-02-13 22:36:33.png

On Ubuntu locate is updated once every do often so it might not find very recent files. You can force an update by issueing a ...

sudo updatedb


Panel indicator for Totem (default movie player) or for audio playing?

In case you use Gnome Shell, there is this extension that might do what you want.

The version 6 of that extension should provide a volume control per application, but it has not been released (as of today).


Ubuntu 17.10 installation from a thumb drive

I am not sure what the problem is but with the DVD you have to leave it in the computer after the reboot, until it tells you to remove it.

This maybe the same when installing via a flash drive.


Filed a bug against gpointing-device-settings #793440. It seems impossible to do what I want with the current version of the software. Question closed.


How do I delete an encrypted folder created with encfs?

After you make sure there's no files in ~/visible, unmount it and simply the delete the ~/.encrypted folder with

rm -rf ~/.encrypted

Or delete it with a file manager


I had the same error.  Burnt a DVD and it worked.  NO clue why. I fought for half a day.  Same error messages you mentions. Then gave up on USB install.


Does SECURE BOOT need to be disabled on the Nexus 5 before I can install UBPort's Ubuntu Phone Image?

The answer is "No".

You do not need to disable secure boot in order to install Ubuntu Touch on a Nexus 5.

Source: I just installed it, and it went fine.


It seems that it takes me about 2 hours, all told.  But I tend to walk away from the computer once in a while, so it could probably be done a bit faster


Ubuntu Server randomly becoming inaccessible and comes back if I reboot modem

Problem I was having exactly the same as better described in here: http://ubuntuforums.org/showthread.php?t=1488953
I solved this issue by upgrading my kernel to 4.1.6. My server is not becoming unreachable anymore.


FOR HP users
If you want to replace Windows 8 with Ubuntu. Download the ISO and burn that to a disc using Nero or InfraRecorder (Infrarecorder is free).

Then restart your laptop. Insert the DVD and press F9 to change the boot loading option.
Select - "Internal CD/DVD ROM" and press ENTER

Laptop will start booting form DVD and the proceed with installation. While installing there is an option for "Replacing windows8 with Ubuntu". Select this option.

Thats it. After successfull installation, let the DVD tray to come out. Remove DVD and close tray and press ENTER.


echo command won't print newlines with the \n sequence. Use printf instead.

printf "mypassword\n" | sudo -S cat /etc/shadow


How can I change the voice used by Firefox Reader View (Narrator) in Ubuntu?

I managed to use the festival voice as default on Firefox.

In order to do that, we need to change some configurations on the file /etc/speech-dispatcher/speechd.conf. But first, I need to explain the basic idea of how it works. We can always see what voice is the default one used by speech-dispatcher using the command spd-say:
spd-say "Hello. How are you?"

On Ubuntu, the default Texto To Speech (TTS) voice that comes with speech-dispatcher is espeak. So we hear exactly the same voice when we use this other command:
espeak "Hello. How are you?"

That happens because spd-say is just using espeak voices as output. And well, Firefox does the same, it uses whatever voice is configured in speech-dispatcher as output to read web pages in the reader view mode (Ctrl+Alt+R).
So, what we need to do here is to change the voice that comes as output in the spd-say command and, once we do that, Firefox is going to use a different TTS voice as default as well. I'm going to describe the process of making it work with the festival voice, but I believe the procedure is the same if you want to run a different TTS voice. First, we need to install festival:
sudo apt-get install festival speech-dispatcher-festival

We can test its voice in the command line by typing:
echo "Hello. How are you?" | festival --tts

Now we need to change the file speechd.conf. So we type sudo vi /etc/speech-dispatcher/speechd.conf on the terminal and around the line 205 we'll see the following piece of commented configurations:
#AddModule "espeak"       "sd_espeak"   "espeak.conf"
AddModule "festival"     "sd_festival"  "festival.conf"
#AddModule "flite"        "sd_flite"     "flite.conf"
#AddModule "ivona"    "sd_ivona"    "ivona.conf"
#AddModule "pico"        "sd_pico"     "pico.conf"
#AddModule "espeak-generic" "sd_generic" "espeak-generic.conf"
#AddModule "espeak-mbrola-generic" "sd_generic" "espeak-mbrola-generic.conf"
#AddModule "swift-generic" "sd_generic" "swift-generic.conf"
#AddModule "epos-generic" "sd_generic"   "epos-generic.conf"
#AddModule "dtk-generic"  "sd_generic"   "dtk-generic.conf"
#AddModule "pico-generic"  "sd_generic"   "pico-generic.conf"
#AddModule "ibmtts"       "sd_ibmtts"    "ibmtts.conf"
#AddModule "cicero"        "sd_cicero"     "cicero.conf"

# DO NOT REMOVE the following line unless you have
# a specific reason -- this is the fallback output module
# that is only used when no other modules are in use
#AddModule "dummy"         "sd_dummy"      ""

# The output module testing doesn't actually connect to anything. It
# outputs the requested commands to standard output and reads
# responses from stdandard input. This way, Speech Dispatcher's
# communication with output modules can be tested easily.

# AddModule "testing"

# The DefaultModule selects which output module is the default.  You
# must use one of the names of the modules loaded with AddModule.

#DefaultModule espeak
DefaultModule festival

It's necessary to make two changes here:

Uncomment the line AddModule "festival"     "sd_festival"  "festival.conf"
Add the line DefaultModule festival

We need to run festival as a server in order to make speech-dispatcher use it as default. We can do that by adding the following line at the end of the file that's open when we use the command sudo crontab -e:
@reboot /usr/bin/festival --server

Now it's done!! After rebooting the system Firefox and spd-say will be using the festival voice as output.

Additional Information
I believe that the procedure to make new voices work in Firefox will be always the same:

Uncomment the module of the new TTS voice that we installed (/etc/speech-dispatcher/speechd.conf).

Set a new default line for the TTS voice that we want (/etc/speech-dispatcher/speechd.conf).

Run a server on the port specified on the files inside the folder /etc/speech-dispatcher/modules/.

What called my attention on that is that there's a module for the Ivona voices there. Ivona is a proprietary product and today the only way to use it (as far as I know) is as a pay-as-you-go service on AWS, but its voices are really good and they sound very natural.
The file /etc/speech-dispatcher/modules/ivona.conf is configured to listen to a server on the port 9123. I think perhaps there's a way to run a local server that gets the Ivona voices using my AWS APIs ( I'm not sure, but perhaps using a part of this Node.js app that's already developed) ... And if that's possible, it means that it's also possible to run Ivona on Ubuntu as the default voice of the system and consequently use it with the reader view mode on Firefox . Although I don't know how to do it now, it looks like an interesting possibility.


17.04 can't get into desktop environment

I can confirm the same behaviour with Kubuntu 17.04. I change to terminal 1 with ctrl+alt+1 and issue
         sudo /etc/init.d/sddm status
gives "running".
If I do
         sudo /etc/init.d/sddm stop
it waits for a while, trying to stop the process, then returns to terminal 7 with the same blank screen. It perhaps respawns sddm.
If I kill sddm thread with kill -9 xxxx xxxx, then also same issue.
If I do
         startx
it takes me to a black screen with the kde default mouse pointer, but frozen.


bash: ./configure: No such file or directory

You should first clone the repository (use git clone https://bitbucket.org/ssoulaimane/webcontentcontrol-gambas3).

After that you should change directory the repository folder using cd webcontentcontrol-gambas3 and only after that you should do ./configure && make && sudo make install.

configure is a file located in that repository and it's written in bash. You don't have any file named configure in your home folder so that's why you have to cd on your repository folder.

By the way, if the command ./configure && make && sudo make install listed above doesn't work use bash configure && make && sudo make install. But I really doubt it won't.

Good luck!


Resume from suspend without waking up hd

I would send the suspend command to the drive on resume.

under /etc/apm/resume.d/
you can add a script that does that.

it would probably look like this

 #!/bin/sh
 # sleep drive when resuming

 case "$1" in
   resume) /sbin/hdparm -Y /dev/sdb;;
 esac


You lack the needed firmware:

  [    4.639432] iwlwifi 0000:02:00.0: no suitable firmware found!

First, verify that you have these two files; iwlwifi-7265D-13.ucode and iwlwifi-7265-13.ucode:

ls /lib/firmware | grep 7265

If so, we are going to make copies but rename them:

cd /lib/firmware
sudo cp iwlwifi-7265D-13.ucode  iwlwifi-3165-9.ucode
sudo cp iwlwifi-7265-13.ucode  iwlwifi-3165-13.ucode

Reboot. Your wireless should be working.


Multiple casper-rw partitions for LiveUSB persistence?

There is no limit for casper-rw partition size.

The only limit is for the casper-rw file on a FAT32 partition. FAT32 file size limit is 4GB

A casper-rw partition may be ext2, 3 or 4.

Besides for a casper-rw file on a FAT32 partition you can have a home-rw file, which gives a separate home folder.

Program updates etc will be stored in casper-rw and home folder data will be stores in home-rw

To make a home-rw file rename a blank casper-rw file.

Note that when booting a persistent Ubuntu install, the first casper-rw file or partition encountered is the one used.

I have never found a method of combining casper-rw files but have never had a reason to.

EDIT 2016

At this time, persistent partitions no longer work with syslinux type installs such as SDC or UNetbootin. They do work with a grub2 type install such as mkusb makes.

It is possible to use multiple casper-rw files as long as each is in a uniquely named folder on a FAT32 partition(s).
see:
MultiBoot with Multiple Persistent partitions

EDIT Aug/2017 - Persistence files > 4GB

Syslinux started adding support for NTFS with version 4.06 but did not offer full support until version 6.03. This allows casper-rw files to be larger than 4GB.


After a full day of fiddling I finally got myself reconnected to my parents' Wi-Fi so I thought I'd put this here for anyone else in a similar situation.

My parents' router is a Liinksys WRT54G. In order to get myself reconnected I deleted the existing connection and created a new one from scratch.

I disabled "Connect automatically" just for schitzengiggle.
Listed the SSID (their's includes a space, which I thought might be a small part of the issue, turns out it doesn't matter)
I specifically left the "Device MAC address:" field blank. When you select a wireless network from the dropdown this field gets filled in automatically.
I left the MTU as automatic.

Under the Wireless Security tab:

Security: WEP 40/128-bit Key (Hex or ASCII)
Obviously enter the WEP key.
I left the WEP index as 1.
Authentication: I changed it to "Shared Key". I think maybe this is the particular thing that fixed my issue.

If things change for me I'll be back to update my question and this answer, but hopefully I'm through wrestling with this. Hope this helps someone else!


Arguments such as -R almost always precede the target of the command. Your first command had the argument after the target and since there was no nameOfFolder -R you will get no such file or directory. Suggest that you read man rm and man rmdir for details of syntax and available arguments.

If the folders are showing up in Nautilus, you can always drag them to the Terminal window after entering the command and arguments and the path to the target will be entered automatically.


how to list all processes as sorted names

You can add an optional --sort= specifier e.g.

 ps -e --sort=args

From man ps

   --sort spec     Specify sorting order. Sorting syntax is
                   [+|-]key[,[+|-]key[,...]]. Choose a multi-letter key
                   from the STANDARD FORMAT SPECIFIERS section.


How to get the details of User(Computer)name and the Password?

Usernames are stored in /etc/passwd - so you can look in here to remind yourself what the usernames are - anyone can read this file.

Passwords are stored (hashed) in /etc/shadow

To reset a user's password:

sudo passwd <username>

-- it will ask you for a new password.

Last question - erm - don't tell anyone?  Not quite sure what sort of suggestion you're looking for here.

If you can't get into the machine at all (so can't look in /etc/passwd) then you have to reset the root password, with which Google can help.


Xubuntu 16.04 DVD playback jumps around in VLC and Parole

After loading and reloading libraries and many apps, I'm concluding that standard apps just won't play Avengers properly.
However, I loaded Kodi and it works! A little overkill for just playing a DVD, but hey, it works.


Tell hash to forget the locations:

hash -r

From help hash:

Options:
  -r    forget all remembered locations

More info: Why does `type which` say that `which is hashed`?


Playing drm encrypted wmv files in Linux

The only way is through Windows Media Player. This leaves you with three options:

Install Windows Media Player 11 on Wine.
Install XP in virtualbox and Windows Media Player 11 on XP.
Dual boot.


you mean adding mailserver sw to the existing OS? Usually we can do that via tasksel, you can launch it from terminal.

Cheers,

Silvia


Open a Terminal and run the following command

gsettings set org.gnome.desktop.a11y always-show-universal-access-status true

This should make the accessibility icon always visible.


Creating a custom Ubuntu Live USB for school exams

Why don't you use Ubuntu constructor to create your own image of what you want?

https://www.maketecheasier.com/reconstructor-creating-your-own-ubuntu-distribution

For timer how about this?

http://ubuntu.pkgs.org/16.04/ubuntu-universe-i386/stopwatch_3.5-5_all.deb.html

Alternatively you may want to modify a 'conky-file' which usually has a segment which shows how long the system has been up and running.

https://www.linux.com/learn/how-install-and-configure-conky

As for preventing wireless access, surely the easiest thing to do is to disable it in the BIOS (it will depend on make and model of notebook) or switch the wireless on/off switch to off and ensure student does not have their hands near the wifi on/off switch.


I am assuming that you want to get just the last line.

To do this, simply add the --newline flag to youtube-dl.

youtube-dl --newline -cit -f 18 URL | grep -e ETA -e "Downloading video #"

This causes the progress to be output to a new line each time, rather than continually erasing and deleting parts of the same line. This is required for your grep command to work.


nvidia-smi hangs. cannot be killed even by SIGKILL

It is probably a GPU error and that is why $nvidia-smi hangs.
Try running:
$ journalctl -p 3 | grep -i "nvidia"
And skim through the logs to find the error message/code for your problem.


No. It will probably be supported if/when it's included in glibc.

The en_DK.UTF-8 locale currently serves a similar purpose, so I would guess that you can achieve basically the same settings this way:

Select English (Denmark) in the Regional Formats tab in Language Support.
Add this line to your ~/.profile file:

export LC_MONETARY=en_IE.UTF-8


My wi fi network is not showing in wi-fi network list

Changing the channel fixed my problem.  To determine which channels are good for you, run this command on Ubuntu:
sudo iwlist wlan0 scan | grep Frequency | sort | uniq -c | sort -n

If you encounter an error like "wlan0 doesn't support scanning", then run this command:
ifconfig

if you can't run ifconfig because net-tools is not installed, install it with the command:
sudo apt update
sudo apt install net-tools

look for output - two words wl mine was wlp3s0, so the command would be
sudo iwlist wlp3s0 scan | grep Frequency | sort | uniq -c | sort -n

The sort -n flag will rank the channels in order of fastest to slowest
Once you've found the best channel,  you change the channel on your router.
then restart your network-manager:
sudo service network-manager restart

You might also want to check if WiFi is blocked - See this related question on Unix&Linux


USB ubuntu - how to retrieve saved data after reboot

Any changes made after booting with an Ubuntu live USB (including files/folders created) are usually erased when you shutdown, unless you made the live USB persistent when you created it.  That means that a file is created on the USB where the changes are stored.  Persistence is usually not done by default - only if you request it when you create the USB.

If you want to make the USB persistent then you'll need to create it again from scratch and make a persistent file.  I believe PenDriveLinux's program and Ubuntu's own live USB creator can make it persistent.

(technically, I don't think the files are actually wiped when you shut down - I believe they only exist in RAM and aren't copied to the USB)


I think my router screws up DNS retranslation.
Following options in the sshd_config fixed the issue, at least partially:

UseDNS no
GSSAPIAuthentication no


How do I configure "initiate_all_edge" for compiz?

I set the compiz scale plugin to activate via BottomLeft and BottomRight corners by using CCSM (CompizConfig Settings Manager.)  You'll need to first install CCSM via the Ubuntu Software Center (or apt-get.)

CCSM > Window Management > Scale > Bindings

The setting you want is "Initiate Window Picker For All Windows" (the one next to the monitor icon.)  Click the ("Disabled" by default) button and set which corners you want to activate Scale with.

You may notice that hovering over the correct setting reveals 'initiate_all_edge' so you can be sure you're editing the right attribute.

This works great for me but occasionally something breaks and I've got to "reset setting to the default value" and then reselect my hot corners to get them working again.

Also it doesn't seem to allow a whole edge to initialize scale for some reason.

Hope this helps


Can access NAS by SSH in terminal but not through Nautilus

Ubuntu Desktop (Unity 3D, 2D)

To connect SSH hosted service with Nautilus, type in to the location bar this string:

sftp://user@host[:port] - SFTP means SSH File Transfer Protocol

The port is NOT necessary if it is the default 22. You also can specify the dir, what you want to access: sftp://user@host[:port][/my/data/dir]

(Image is illustration, from Nautilus 2 - its update sheduled)

It will prompt for password.

Ubuntu Classic (GNOME 2.x)

Also you can use the Connect to Server function from the Places menu...

(It may also available in Unity, by a search in Dash.)

(Images are illustration.)

The [] are used to mark/express OPTIONAL information/data/string/etc.
Thanks for images to howtogeek.com.


I can't log in after I inserted some variables in my environment file

Login via Ctrl+Alt+F1.
Run this command:

nano "$(grep -l 'export JAVA_HOME=/media/F25ACC3E5ACBFCFB/Program Files (x86)/Java' ~/* 2>/dev/null | head -n1 | tr -d '\n')"

Delete this line (should be at or near line 31):

export JAVA_HOME=/media/F25ACC3E5ACBFCFB/Program Files (x86)/Java

Save and exit with Ctrl+X, Y, Enter.
Login should now work.

For how to install Java correctly, see How do I install Java?.


Really slow Video on 14.04 with a nvidia GeForce4 420 Go 32m

I have answered how to uninstall and update the nvidia drivers here: Stuttering screens on 14.04 on MacPro

It uninstalls the nvidia driver(s) and then installs a more stable version through a repository. Hope this helps!


How do I boot the live CD on a Macbook Pro?

Sorted, for all others out there, hold the Alt key down, then wait a while until a CD icon appears, then select in order to boot from CD.


Text editor default Calendar and cannot be changed in Ubuntu 20.04

gedit /home/yourname/.local/share/applications/mimeapps.list
Abbreviated file:
[Default Applications]
text/calendar=org.gnome.Calendar.desktop

[Added Associations]

Full file:
[Default Applications]
application/x-deb=gdebi.desktop
x-scheme-handler/http=google-chrome.desktop
x-scheme-handler/https=google-chrome.desktop
x-scheme-handler/ftp=firefox.desktop
x-scheme-handler/chrome=firefox.desktop
text/html=google-chrome.desktop
application/x-extension-htm=firefox.desktop
application/x-extension-html=firefox.desktop
application/x-extension-shtml=firefox.desktop
application/xhtml+xml=firefox.desktop
application/x-extension-xhtml=firefox.desktop
application/x-extension-xht=firefox.desktop
x-scheme-handler/mailto=thunderbird.desktop
message/rfc822=thunderbird.desktop
application/x-extension-eml=thunderbird.desktop
application/x-mimearchive=firefox.desktop
application/x-ms-dos-executable=wine.desktop
application/x-shellscript=gedit.desktop
text/xml=firefox.desktop
application/xhtml_xml=google-chrome.desktop
image/webp=google-chrome.desktop
application/xml=firefox.desktop
application/rss+xml=firefox.desktop
application/rdf+xml=firefox.desktop
image/gif=firefox.desktop
image/jpeg=eog.desktop
image/png=eog.desktop
video/webm=firefox.desktop
application/x-xpinstall=firefox.desktop
x-scheme-handler/enpass=Enpass.desktop
x-scheme-handler/about=google-chrome.desktop
x-scheme-handler/unknown=google-chrome.desktop
text/calendar=org.gnome.Calendar.desktop

[Added Associations]
application/x-deb=gdebi.desktop;
x-scheme-handler/https=firefox.desktop;google-chrome.desktop;
x-scheme-handler/ftp=firefox.desktop;google-chrome.desktop;
text/html=firefox.desktop;google-chrome.desktop;
application/x-extension-htm=firefox.desktop;
application/x-extension-html=firefox.desktop;
application/x-extension-shtml=firefox.desktop;
application/x-extension-xhtml=firefox.desktop;
application/x-extension-xht=firefox.desktop;
x-scheme-handler/mailto=thunderbird.desktop;
message/rfc822=thunderbird.desktop;
application/x-extension-eml=thunderbird.desktop;
application/x-mimearchive=firefox.desktop;
application/x-ms-dos-executable=ghex.desktop;wine.desktop;
x-content/image-dcf=rhythmbox.desktop;
application/x-executable=ghex.desktop;
application/x-shellscript=gedit.desktop;
application/pdf=libreoffice-draw.desktop;
text/xml=google-chrome.desktop;firefox.desktop;
application/xhtml_xml=google-chrome.desktop;
image/webp=google-chrome.desktop;
application/xml=firefox.desktop;
application/rss+xml=firefox.desktop;
application/rdf+xml=firefox.desktop;
image/gif=firefox.desktop;
image/jpeg=firefox.desktop;eog.desktop;
image/png=firefox.desktop;eog.desktop;
video/webm=firefox.desktop;
application/x-xpinstall=firefox.desktop;
inode/directory=nautilus-folder-handler.desktop;

gio mime text/calendar


Having trouble downloading Ubuntu 20.04 iso

GUI Solution: You can install and use FDM as your download manager and download file using this.

Non GUI Solution: Or using curl from the command line.

Torrent Solution:  Use Transmission and BitTorrent file available in Alternative downloads. Although FDM can download torrent files.


problem with crontab entry with time tag

Yeah I understood. The percentage signs have to be escaped as % is the new line specifier in crontab. The following works

*/1 * * * * /usr/bin/env > /home/vasu/env.output.$(date +"\%d\%b\%y.\%R")


storing millions of files in Ubuntu 16.04

Read the man page for mkfs.ext4, and using the -i, -I, and -N arguments, set up the filesystem with the inodes it needs to meet your needs.  In a terminal, either
 man mkfs.ext4
 for a terminal display or
 xman mkfs.ext4
for a GUI display


Data from such a repository can't be authenticated

First of all make sure that, this works:

sudo rm -rf /var/lib/apt/lists/*
sudo rm -rf /etc/apt/sources.list.d/*
sudo apt-get update

If it did not work, count that, I did not found any other choice for you besides running

sudo apt-get update --allow-unauthenticated

This is a security risk, but if you are ready for this you can use --allow-unauthenticated flag for some other apt commands.


upgrade from Ubuntu 8.04 LTS with an old computer

Free some data using a "Disk Analyzer Tool".

The best option to do is to:

Backup everything you want to save to Google Drive
Download the new Ubuntu 14.04 LTS (You could get back the Gnome Desktop Back if you want http://goo.gl/OR2Oyz)
Create a bootable in a flash drive with ubuntu http://goo.gl/9727vE
Then try reinstalling it


How to install Ubuntu touch on X86 tablet with windows 8?

Unfortunately Ubuntu touch x86 for tablet has not been released yet. When it is, it will be based on the all-new non-LTS Ubuntu 16.10 Yakkety Yak, which will be released next month (October).

The Preinstalled Touch Image allows you to install a preinstalled preview of Ubuntu Touch onto a target device.
 • Ubuntu Touch 16.10 (Yakkety Yak) Daily Build


You need an active DHCP to assign a proper IP to the newly formed controller on the LXD


Try updating from the terminal. Not sure if this will work, but just paste this in:

sudo apt-get update && sudo apt-get upgrade && sudo apt-get dist-upgrade


For 14.04 you can just install postgresql-client (as it depends on postgresql-client-common):

sudo apt-get install postgresql-client

To quickly know which package contains a command/binary missing on your system, just use package.ubuntu.com (Search the contents of packages).


webcam flipped aka v4l1compat.so troubles

You have to install 32 bit (i386) version of libv4l-0:

sudo apt-get install -y libv4l-0:i386

then start Skype with this command:

LD_PRELOAD=/usr/lib/i386-linux-gnu/libv4l/v4l1compat.so

or modify the Exec command in /usr/share/applications/skype.desktop


How can I create a root user from the start of installing Ubuntu?

The user root already exists by default when a Linux system is created, or at least, a user must exist with UID 0 who has all permissions and owns most of the system files. Traditionally this user is called root. You do not need to create that user.

When you install Ubuntu, you are prompted to create a user for yourself. This is because it is inadvisable to run the system as root, because root always has all permissions and programs run as root may do whatever they want, which is a security risk. Running commands and other programs as an unprivileged user wherever possible is safer. But, the user you create at installation is not limited in their rights. That user is automatically made a member of the group sudo and is allowed to run any command as root by using the sudo program. This means you can make use of sudo to do anything you want on the system, even to run whole shells and other programs as root, as SteveInBavaria pointed out.

Ubuntu is slightly different from many other Linux distros in its approach, because it disables logging in as root by not setting a password for root. On many Linux systems, when you want to elevate privileges, you become the root user by typing su - or just su in a terminal. The su (switch user) command allows you to log in as another user in a shell. You must enter the password of the user you want to log in as, not your own password. On Ubuntu su fails because root has no password. You can "fix" this by setting a password for root, but this is discouraged and not necessary since sudo provides all privileges. You can even run the su command as root by typing sudo su. Then you type your own password and become root. However, since sudo provides a way to open a root shell there is no need to run the su program with it for this purpose. You can simply use sudo -i.


Change from windows 7 to ubuntu 14. And doesnt work

Please do not use Wubi any more. It was discontinued about 3 yrs or so ago. Instead, burn the Ubuntu ISO to a DVD or USB from within Windows and install Ubuntu by booting off it.

As you have installed Ubuntu using Wubi, uninstall it again in the same way, meaning uninstall it from Windows' Control Panel.

Now boot off the created USB or DVD and install Ubuntu from there using manual partitioning or the "Alongside Windows" option.

EDIT: To get back to Windows, try to open the GRUB2 (Ubuntu's boot loader) menu by pressing ↑Shift during boot. If that doesn't work, press Ctrl+Alt+Del when the error message is shown. It should reboot and take you to the boot menu.

If the Windows entry is shown in the menu, simply select and boot it. It may be hidden in something like "Other operating systems". If it isn't there, press C to drop to the GRUB shell. Now execute the following command:

chainload (hd0,0)+1

This will let GRUB load the first sector of the first partition of the primary disk, most likely where Windows is installed. If it doesn't work, use the command ls to get a list of partitions and try to chainload each of them using above command. If you manage to boot Windows, immediately uninstall Ubuntu using above described method, which should reinstate the Windows boot loader.

If all of this fails and you cannot get Windows back, boot a Windows (Vista or later) installation disk and run the Boot repair utility off it. This should reinstate the Windows boot loader.