Your operating system is neither the first code that executes on your computer, nor is it the code with the highest level of access. Malware loaded into the bootstrap code (including BIOS, video BIOS, RAID BIOS, NIC BIOS, UEFI, UEFI modules) not only will not be erased by installation of a new OS, it can hide itself from detection by the OS (although not perfectly, it will slow things down1 and timing analysis may be able to detect that).

Only a small fraction of all malware operates at this level, but multiple cases have been documented. Here are just a few examples:

New BIOS Virus Withstands HDD Wipes
Blue Pill is the codename for a rootkit based on x86 virtualization
Rootkit Detection Framework for UEFIWay Back Machine "UEFI has recently become a very public target for rootkits and malware. Last year at Black Hat 2012, Snare’s insightful talk highlighted the real and very significant potential for developing UEFI rootkits that are very difficult, if not impossible, to detect and/or eradicate. Since then, a couple of practical bootkits have appeared."

Also, Stack Exchange site Information Security has several relevant questions:

How to detect a virus in a network card?
Viruses on video cards?

To be pedantic, these wouldn't be called "Windows viruses", although they may be carried inside Windows malware which served as the infection vector.  And they wouldn't be said to "transfer to Ubuntu".  My point is that if you had asked the right question, which I feel is "After formatting my Windows partition and installing Ubuntu, might I continue to be affected by malware?", you would learn that the unfortunate answer is "Yes that is possible."

1 But malware that infects a coprocessor, such as the Intel Management Engine which has recently come to mainstream attention due to a critical vulnerability in the way Intel does remote authentication would not spend processor cycles.  At best it might cause some timing variances due to bus and memory contention.  Malware that infects a management subsystem is basically a worst-nightmare scenario, for both detection and removal.


Changing send_selection_unsafe=false to send_selection_unsafe=true in the geany.conf file (~/.config/geany/geany.conf) fixed this for me.


PRIME Displays cannot be controlled by nvidia-settings

Here is my recent revised solution on Ubuntu 18.04 to get screen synchronization on my External Monitor to ...

... STOP SCREEN TEARING!! with Nvidia Drivers in use

04/12/18
∘ PRIME Synchronization on Optimus

To check:

sudo cat /sys/module/nvidia_drm/parameters/modeset

It Should say "y" for modeset=1, for your Monitor ex. HDMI-1-1, or  eDP-1-1

To get PRIME Synchronization on Optimus when it says "N" for NO , create a new file in  /etc/modprobe.d/nvidia-drm-nomodeset.conf

sudo gedit /etc/modprobe.d/nvidia-drm-nomodeset.conf

And make sure the following line is present;

  options nvidia-drm modeset=1

And after a Reboot or Update Intramfs
Here is the Update Intramfs code
sudo update-initramfs -u

Now sudo cat /sys/module/nvidia_drm/parameters/modeset, will give a Y for Yes, and screen tearing is greatly reduced!


signature verification error for wine - index files failed to download - changing mirror doesn't help

As of 2018-12-19 08:07 there is a new winehq.key keyfile as mentioned here.

Download the new repository key and add it to the list of trusted keys:

cd /tmp
wget -nc https://dl.winehq.org/wine-builds/winehq.key
sudo apt-key add winehq.key
sudo apt update

As mentioned by @jason-hunter in a comment, apt update will ask if you accept the changes in the repository, whereas apt-get update will show an error and fail.


When you run your jar using java -jar myfile.jar you're telling your shell to run the java command and passing it some arguments which java understands. However when you're running it using ./myfile.jar you're asking the shell to determine the interrupter to run it with, which it's unable to do.

The shell looks for the shebang line at the beginning to the script to known which application to run the script with, which is why you'll see shell scripts starting with:

#!/bin/bash

Or python scripts start with

#!/usr/bin/python

What you're telling the shell, basically, is to run the script using the application you find at /bin/bash or /usr/bin/python. In the case of your jar file, the shell is unable to find the shebang so it doesn't know how to execute the code.

In the past I've used wrapper scripts to execute Java applications, so something similar to:

#!/bin/bash

java -jar /path/to/myfile.jar

Then you just need to make that executable, using chmod and you can run it as you would any other shell script.


Xubuntu on Macmini, Would not boot, stupidly reset PRAM

Try this:

Using any emergency disc you like (Linux or OS X), prepare a small non-journaled HFS+ partition. ("Small" = ~100MiB to 1GiB.) Chances are you'll need to shrink another partition to do this, of course. Backing up that partition is highly advisable.
Download the rEFInd binary .zip file and unpack it somewhere convenient (such as that HFS+ partition you've just created).
Boot from an OS X installation/emergency disc.
Once you get to the point where a menu bar is visible, use it to open a Terminal window.
Install rEFInd by running install.sh with its --ownhfs option, as in sudo ./install.sh --ownhfs /dev/disk0s5, changing /dev/disk0s5 as necessary.
Reboot.

The result should be that rEFInd will appear and enable you to boot. It will also appear in a location that should cause the firmware to find it and present it in its menu when you hold down the Option key while booting, so you should be able to recover a little more easily in the future. Some caveats:

The --ownhfs option to install.sh is new, so be sure to use rEFInd version 0.7.6 or later. (0.7.6 is current as I write.)
When I've tested this method of booting, rEFInd has failed to scan some partitions. If this happens, hit the Esc key to have rEFInd re-scan for boot loaders. Uncommenting the scan_delay option overcomes this problem permanently. (Setting the value to 1 is probably adequate.)
If rEFInd is reading your Linux kernels from a Linux filesystem, you'll need to either manually install the driver(s) or use the --alldrivers option to install all the drivers. If you do the latter, manually removing the drivers you don't need is advisable.

If you don't have an OS X emergency disc or if this procedure doesn't work, you could try installing it from Linux using the --usedefault option to install rEFInd to the ESP using the default/fallback filename, as in sudo ./install.sh --usedefault /dev/sda1. Some (but not all) Macs will boot from the default/fallback filename if they can't find another boot loader, so this may work well for you; but if your model doesn't use the default/fallback filename, this alternate procedure will fail.


According to the docs it says to update the settings in /etc/apt/apt.conf.d/20auto-upgrades. So I would update these settings to "0" as well:
APT::Periodic::Update-Package-Lists "0";
APT::Periodic::Unattended-Upgrade "0";

But to be super sure you could still edit /etc/apt/apt.conf.d/10periodic and update the following settings to "0":
APT::Periodic::Update-Package-Lists "0";
APT::Periodic::Download-Upgradeable-Packages "0";
APT::Periodic::AutocleanInterval "0";

Once you have made the updates above none of the packages managed by APT will be automatically updated including MySQL, Apache and PHP.
It's fine to also set APT::Periodic::Update-Package-Lists to "0" as you can still manually update the package lists when you like with sudo apt update and manually update your packages with sudo apt upgrade.
You shouldn't need to make any updates to /etc/apt/apt.conf.d/50unattended-upgrades.
You may also want to disable snap packages from auto-updating however MySQL, Apache and PHP are usually managed by APT so this shouldn't be necessary if you are only really concerned with those packages not being automatically updated.
Important: Disabling automatic updates also means you won't be receiving important security updates for your system so unless you are in the habit of regularly updating your software packages it's probably best to leave automatic updates enabled.


Thunderbird 37.1.0 disable Send Now keyboard shortcut

If you installed keyconfig, but you can't find the "Send Now" option:

1) Open Thunderbird

2) Start composing a new message (in a new window)

3) In the main Thunderbird window, go to the Tools menu > Keyconfig

4) At the top of the Keyconfig window, there is a dropdown box, with one entry for each open Thunderbird window
for example:
- Inbox
- Write (no subject)
- Keyconfig

5) Choose the "Write . . ." window in the Keyconfig dropdown box

6) Send Now should now be listed in the Keyconfig listbox

7) Select Send Now, and click Disable


It looks like your problem is that some of your packages depend on other ones and this is causing apt to get stuck. I'd say open terminal and run sudo apt install linux-image-3.13.0.73-generic, because that package is not installed and seems to be the cause of the problems. Just install that package and then report back whether it worked. It should resolve that dependency error.

Now looking at edits in the question, your /boot is full, so try running,

sudo apt-get autoremove

to remove old kernels and initrds stored there. Then run

sudo apt-get install linux-image-3.13.0.73-generic.

This should fix the dependency problems


gnome-panel icons duplicated across multiple monitors

community wiki - OP had added the answer into their question

I write it for people with the same problem.

The problem was not in Unity. Ubuntu thought, that I have two monitors: notebook and unknown. Because unknown monitor was overlayed some space on the notebook monitor, panels was duplicated.

The solution:

Go to "System settings", "Monitors", and drag out unknown monitor, until it not hide from gray field.
select your monitor, select default resolution(ex. "1366x768") and click "Apply".
now we can't do something in GUI, we go to TTY by pressing Ctrl+Alt+F1
and reboot, by using sudo shutdown -r now command.

It works fine for me. Hope it help. Problem, maybe, raised because I disabled the Radeon video adapter.


cannot easily switch to virtual consoles -- why?

Yes, there is something different about the virtual consoles depending on which version of Ubuntu you have updated from.
On older versions of Ubuntu, lightdm was present on TTY7. However on newer versions, GDM is present on TTY1 and TTY2.
So on 20.04, you should be able to access a virtual console on TTY3~TTY8.
Please see this similar question if you would like a more in depth answer as to why you see both a lockscreen on TTY1 and a normal session on TTY2. However, I don't think installing lightdm is necessary as the answer suggests.


Could you post a screenshot? When does it show the error, after settings your preferences?

I installed installed Ubuntu 12.04 yesterday using the Wubi.exe from the live-cd (after copying it to my desktop) and it worked. It used the files from the cd.


Ubuntu Server 18.04 suppress DHCP gateway

I figured it out.
First remove the entry from /etc/netplan/01-netcfg.yaml, and then create /etc/systemd/network/no-route.network file:

[Match]
Name=enp0*

[Network]
DHCP=yes

[DHCP]
UseRoutes=false


No apt-get functions working, have tried almost all fixes but none work?

This should fix it:
sudo apt-get autoclean

Or
sudo apt-get clean


MaaS server with local kvm - How to bridge to dhcp interface

Ok, I had a few problems. My eth1 was still defined as static in my /etc/network/interfaces. I had to remove it, and change my br0 with matching static settings. Then on the Cluster master in MaaS, change the Managed DHCP-DNS interface from eth1 to br0.

Hope this helps someone.


Read again:

  To edit the list of insults, you will need to edit the source and recompile.

So get the source and dependencies:

apt-get build-dep sudo
apt-get source sudo
cd sudo*

Edit the files. Note that there is no leading slash, since this is a relative path:

vim plugins/sudoers/ins_*.h

Build:

dpkg-buildpackage -us -uc -b

Install:

sudo dpkg -i ../sudo_*.deb


Why does my ubuntu 18.04 get stuck on the 'purple' screen after logging in?

There are two relevant bug reports on the "purple screen" in Ubuntu 18.04 LTS. Many people have encountered difficulties including myself. However my problem seems different than the two bug reports so there might be more in the future regarding this issue.

Here are the two bug reports:

[regression] Password accepted but login fails (blank purple screen and mouse pointer only)
 [regression] Ubuntu 18.04 login screen rejects a valid password on first attempt. Usually works on the second attempt

My problem/solution not in the bug reports was this:

Upgrade Ubuntu 16.04 LTS to 18.04 LTS = 5 desktop environments


Despite what some other people are suggesting, formatting a partition generally doesn't erase all the data on it. However it doesn't exactly keep them either. It wipes the file table that records what files are stored on the partition and where. Generally the data for all the files will be there, but as you start using the partition it will get overwritten with new files. You are unlikely to be able to go back to NTFS and have all the files, directory structure etc exactly as it was before. You are unlikely to be able to get Windows to boot properly without reinstalling it. You should be able to recover most of the files using a file recovery tool such as TestDisk or PhotoRec, but there is no garauntee.

http://www.cgsecurity.org


What accounts for the smaller size of open source apps?

You mean smaller on disk? Probably thanks to the extensive use of dynamically linked libraries, that are shared between multiple applications. Of course Windows also supports that, but DLLs aren't easily versioned, and the risk of "DLL hell" doesn't encourage sharing.


How to make a centred, wrapped and padded container of elements in QML?

Your Item doesn't have width and height defined, so it takes the height of the children and the wrapping breaks.

This code probably does what you want, but maybe you need to tweak some margins:

import QtQuick 2.0
import Ubuntu.Components 0.1

MainView {
    width: 800
    height: 600
    Tabs {
        Tab {
            objectName: "Tab2"

            title: i18n.tr("Title")
            page: Page {
                Item {
                    anchors.fill: parent
                    Text {
                        anchors {
                            left: parent.left
                            right: parent.right
                            verticalCenter: parent.verticalCenter
                        }
                        id: text1
                        text: "orem ipsum dolor sit amet, consectetur adipiscing elit. Fusce in mollis purus\n\n" +
                              "Etiam sagittis fringilla quam, eget accumsan libero pulvinar ac."
                        wrapMode: Text.Wrap
                        horizontalAlignment:Text.AlignHCenter
                    }
                }
            }
        }
    }
}

If you want to keep the two Text items separate, you can also use a Column:

import QtQuick 2.0
import Ubuntu.Components 0.1

MainView {
    width: 800
    height: 600
    Tabs {
        Tab {
            objectName: "Tab2"

            title: i18n.tr("Title")
            page: Page {
                Column {
                    spacing: units.gu(2)
                    anchors {
                        left: parent.left
                        right: parent.right
                        verticalCenter: parent.verticalCenter
                    }
                    Text {
                        anchors {
                            left: parent.left
                            right: parent.right
                        }
                        id: text1
                        text: "orem ipsum dolor sit amet, consectetur adipiscing elit. Fusce in mollis purus"
                        wrapMode: Text.Wrap
                        horizontalAlignment:Text.AlignHCenter
                    }

                    Text {
                        anchors {
                            left: parent.left
                            right: parent.right
                        }
                        id: text2
                        text: "Etiam sagittis fringilla quam, eget accumsan libero pulvinar ac."
                        wrapMode: Text.Wrap
                        horizontalAlignment:Text.AlignHCenter
                    }

                }
            }
        }
    }
}


Lost drivers after a update on Ubuntu 18.04 LTS

To manually check your filesystem with fsck...

boot to a Ubuntu Live DVD/USB
open a terminal window
type sudo fdisk -l
identify the /dev/XXXX device name for your "Linux Filesystem"
type sudo fsck -f /dev/XXXX # replacing XXXX with the number you found earlier
repeat the fsck command if there were errors
type reboot

Update #1:

Note: do NOT abort a bad block scan!

Note: do NOT bad block a SSD

Note: backup your important files FIRST!

sudo e2fsck -fcky /dev/sdb1 # read-only test

or

sudo e2fsck -fccky /dev/sdb1 # non-destructive read/write test (recommended)

The -k is important, because it saves the previous bad block table, and adds any new bad blocks to that table. Without -k, you loose all of the prior bad block information.

The -fccky parameter...

   -f     Force checking even if the file system seems clean.

   -c     This option causes e2fsck to use badblocks(8) program  to  do  a
          read-only  scan  of  the device in order to find any bad blocks.
          If any bad blocks are found, they are added  to  the  bad  block
          inode  to  prevent them from being allocated to a file or direc‐
          tory.  If this option is specified twice,  then  the  bad  block
          scan will be done using a non-destructive read-write test.

   -k     When combined with the -c option, any existing bad blocks in the
          bad blocks list are preserved, and any new bad blocks  found  by
          running  badblocks(8)  will  be added to the existing bad blocks
          list.

   -y     Assume  an answer of `yes' to all questions; allows e2fsck to be
          used non-interactively.  This option may not be specified at the
          same time as the -n or -p options.


Phone connecting as mass-storage: how can I import photos?

Have you tried to go under System Settings and select Removable Media ?  Also, on the Android-based phones, you have to select whether or not the phone makes itself visible as USB drive.


Use Gparted to resize the Ubuntu OS installation to a size small
enough to fit on your USB drive.  You can resize it to 12GB.
Use DD or a GUI drive backup utility such as Clonezilla to backup
the 12GB drive to the USB stick.  Your USB stick should now be
bootable as if it were your original hard drive.
For Virtualization converting the USB drive to VDI use
VBoxManager.
You can store the 12 GIG USB drive as an image DD or Ubuntu's GUI
Disk Manager.

The Steps in detail

Resiz3 the Disk.

You'll have to use a Live session (or a different boot drive to run Gparted.  The drive can't be in used while performing the resize.

Backup your Disk to the USB stick.

You can back it up with this commandline using DD:

$ dd if=[source drive/image] of=[destination drive or image] bs=4M status=progress

Source Drive - The USB stick (ie /dev/sdb, /dev/sdc, etc)
Destination drive or image:

You can also use the GUI method via Clonezilla to backup the harddrive to USB drive (or an image).

Convert to a Virtual Disk

If you backed up the drive as an image, use this command to create a VirtualBox image:

$ VBoxManage convertdd input.img output.vdi

Use this command to create the VirtualBox image from the USB drive itself:

$ VBoxManage convertfromraw /dev/sdX MyImage.vdi --format VDI

(The /dev/sdX will be /dev/sda, /dev/sdb, (or the appropriate device of your USB drive.))

You can transfer Device to Device using Clonezilla

The Clonezilla application has the option of transferring your USB drive (device) directly to your HardDrive (device).

Summary

After you have transferred the Smaller USB drive to the larger Hard Drive, you will have to use Gparted to resize the Drive/Partitions to regain the space available on the larger hard drive.


Yes,, if you load and run the beta, and install upgrades as they become  available it will become the release version.

As to stability, it is a beta version.  Alpha versions have been run for some time (I run one in a VM) and I have experienced few problems, but this is only an opinion.


App for taking a screenshot, editing and uploading it to a server

You can view some options (none specifically KDE AFAICT) at this question: What's a screenshot application which will auto-upload to imgur?


The package name is actually linux-headers-generic-lts-wily that you want to install. This should pull in the headers and keep them updated with kernel updates you install.


If your are using an older version of the ubuntu live cd, you might need to change the package source. (I had this problem with the Natty (11.04) live cd.)

Start Synaptic, and in the menu go to Settings -> Repositories. Go to the "Other Software" tab, and select the line http://ppa.launchpad.net/yannubuntu/boot-repair/u... main and then click on the Edit button down below.
In the new window that pops up change the distribution: field to "quantal" (without quotes).
Repeat steps 1 and 2, except this time select http://ppa.launchpad.net/yannubuntu/boot-repair/u... (Source Code) , and then close the window.
Now, either click the reload button in synaptic, or enter into the terminal

  sudo apt-get update

  sudo apt-get install boot-repair

That's it! Boot Repair is now installed.


I'm using Xmonad with Unity in Ubuntu 12.04 and it is working well. I don't use the launcher panel - I hide it in workspace 9 - but I do use the top panel.  I believe that you can use the launcher if you want to though.

Be aware that Xmonad does not support 3D rendering - so you will have to use the 2D version of Unity in Ubuntu 12.04, which is differs from the 3D version in some ways.

Follow the instructions here:
http://www.haskell.org/haskellwiki/Xmonad/Using_xmonad_in_Unity_2D

I recommend configuring Nautilus to disable desktop icons. Otherwise you will get awful rendering artifacts if you are using multiple screens: http://ubuntuforums.org/showthread.php?t=1882688

The procedure will be different in Ubuntu 12.10 since Unity 2D is no longer available in that version.  However, the 3D version of Unity has fallback support for 2D window managers in 12.10; so you may get an experience that is actually closer to the regular 3D version.

In case you are interested, my Xmonad config is here: https://github.com/hallettj/config_files/blob/master/.xmonad/xmonad.hs

Update 2012-12-02: I upgraded to Ubuntu 12.10 and I was not able to get Xmonad to work with the new version of Unity after all.  It turns out that Unity 2D was designed differently in that it implemented the panel as a separate component that could be used with any window manager.  Although the new version of Unity does have a fallback mode for machines that do not support graphics acceleration, it does not have the same modular design.

I have switched to running Xmonad with Gnome Classic.  I'm already missing the integrated menu bar that Unity provided :(


upstart job works only with manual start/stop

As of my experience you don't have to "enable" anything, just put the .conf in /etc/init and enjoy.

You can verify that the script does run by adding a line like this in the script:

echo "alive" > /alive_and_well

This will create file "alive_and_well" in your root dir if the script runs.

If it doesn't, the problem is most likely in the "start on" stanza. Here's what I use for such things (known to work):

start on (local-filesystems and net-device-up IFACE!=lo)
stop on runlevel [!2345]

Also shebangs in Upstart scripts are not supported, so "#!/bin/bash" is useless (AFAIK).


Grub is still needed, it tells the OS what kernel to load. You can hide Grub by changing its settings and make it so that it immediately boots to ubuntu and never shows you any options. An easy program to do this with is grub-customizer and then going through settings to make it so that the autoboot is ubuntu and the time delay is 0.


Install the package libreoffice-pdfimport:

Or by using the command sudo apt-get install libreoffice-pdfimport and Writer will be able to open your PDF's correctly, then you can save them in ODT or DOC.


Transfering files from my HTC to my laptop fails via Bluetooth, Why?

This might be happening because by default ubuntu doesn't recieve files over bluetooth. One  possible solution might be to enable recieving files over bluetooth. Open the personal file sharing preferences window.
Then you'll see this window.
Just check the 'Recieve files in Downloads folder over bluetooth' and you're good to go.

For Ubuntu 18.04 and later:

File sharing can be changed in Settings -> Sharing,
which is turned OFF by default.

Also you might need to reconnect after changing this.


Ubuntu 11.10 recently installed, purple screen, then text shown

For anyone looking for a workaround.
-ALT+F1 or F2 etc to get to another session
-Enter in credentials
-Enter "startx" no quotes in the prompt and hit enter
It should load up your desktop and get you GUI access to the system. I just set autologin for my user so I dont know how to fix the actual login screen not starting.


Error while installing ROS Indigo in Ubuntu 14.04

I met the same errors with yours when I re-installed the ROS-Indigo on Ubuntu 14.04.
I solved this problem following the 3 steps:

Remove ROS-Indigo: sudo apt-get purge ros-*
Update: sudo apt-get update
Upgrade: sudo apt-get upgrade

Maybe it will take a while.


Except for docky, it's just a bunch of data (xml and png), so for a certain definition of "safe" (if you already have installed PPAs) then, yes, it's safe...

Now, before you go ahead, please note that one of the few vectors for getting malware onto your computer is a PPA, so never install a PPA because someone tells you so (including me).  Always use your own personal judgement and do some research before installing a PPA!  Having said that, a PPA with 1000s of users mentioned in numerous articles is always better then installing ppa:maffia.it/BotNet with a few 100 users!  ;-)


Installing Ubuntu over Mint in a dual boot configuration

No,
You should still use dev/sda as a hdd selector
You should have a partition for the current computer, only that unless you back track


On a desktop, is using 'suspend' beneficial?

Suspend usually comes important in laptops when you close the lid.
Its better to hibernate in case of Desktops


Why is the following bash command not working properly?

Better do that:

if [ -d /var/www ] ; then touch folder_exists ; else touch folder_absent ; fi

The first version of the command does the following: $( ... ) is first replaced by whatever was produced by .... Since you call ls -l | grep www, you are either getting a line with multiple words, or nothing. In the first case it is attempted to be executed, but that makes little sense. What will you get if you type

drwxr-xr-x 15 root root     4096 Aug 20 13:48 log

at the command prompt? There is no command called drwxr-xr-x. If you use the cat $( ls -l /var | grep www) form, then first the $( ... ) is replaced by what was produced by ..., then cat interpretes it as a list of files to cat (starting with drwxr-xr-x; most likely, there is no such file).

Moreover, if you attempt to do something like that:

command > cat file

What will happen is that cat is interpreted as a filename to store the output of command, and not as a command. To interpret cat as a command, you need a pipe sign, like you correctly used in ls | grep:

command | cat

However, if your purpose is to store the output of command in a file, then just use

command > file

As a matter of fact, you could do

ls /var | grep www > file

This file will be empty only if there is no www folder in ls. But beware! if there is a folder  /var/ewwwocks, then the file will also contain a line. Better to use simply

ls /var/www > file

Long story short, use the conditional construct if ... ; then ... ; else ... ; fi


All of my video is going fast, and has no sound

It was just that the sound settings were set to S/PDIF instead of Speakers for some reason.

Why that would effect video playback, I have no idea.


You could try making a AP hotspot, e.g. using a script called ap-hotspot (infrastructure Access Points can be more reliable):

To set up a simple wifi hotpsot for Android and other devices, you can use ap-hotspot as detailed here. Basically, install it:

sudo add-apt-repository ppa:nilarimogard/webupd8

Press Enter to confirm this - then run these to actually install it:

sudo apt-get update
sudo apt-get install ap-hotspot

Use ppa's at your own not-very-high risk - note you need to add the PPA and run the update command before you are able to install it.
Start it with:

sudo ap-hotspot start

You can also stop it:

sudo ap-hotspot stop

and configure it:

sudo ap-hotspot configure

Ubuntu 14.04 needs a special fix as well - plz see the big note at end of this post:

  For Ubuntu 14.04:

  also the hostapd version in Ubuntu 14.04 is buggy and doesn't
  work properly. To get AP-Hotspot to work with hostapd in Ubuntu 14.04,
  you need to downgrade hostapd and use apt to hold the package so it's
  not upgraded (thanks to spupuz for the tip!). To do this, use the
  following commands:

  64bit:

cd /tmp
wget http://old-releases.ubuntu.com/ubuntu/pool/universe/w/wpa/hostapd_1.0-3ubuntu2.1_amd64.deb
sudo dpkg -i hostapd*.deb
sudo apt-mark hold hostapd

  32bit:

cd /tmp
wget http://old-releases.ubuntu.com/ubuntu/pool/universe/w/wpa/hostapd_1.0-3ubuntu2.1_i386.deb
sudo dpkg -i hostapd*.deb
sudo apt-mark hold hostapd

If you want to update hostapd you need to unhold the package - ap-hotspot won't work anymore though.

Big Note: ap-hotspot is out of date and not really maintained anymore - as far as I can tell it should work on Linux OSs based on Debian Wheezy, and on 14.04 with above workaround (which uses a old version, which isn't great for varying reasons) - however I do know it seems to work very well on varying hardware.

There are alternatives (e.g. create_ap) - also you can use the variety of instructions here - you could also try setting the mode to infrastructure in the 'Network Connections' settings (this may be the default with newer versions of Gnome/NetworkManager):


This can be done by changing parameters in Xfce's kiosk mode related files.

For example, to remove the Save Session button, follow these steps.

From the terminal, create a directory sudo mkdir -v /etc/xdg/xfce4/kiosk
Next, create this file: sudo touch /etc/xdg/xfce4/kiosk/kioskrc
Edit the file and add the following lines:

    [xfce4-session]
    SaveSession=NONE

Reboot your computer.

The option for saving your sessions will no longer be on the logout session menu.

You will need to take a look at the documentation for other customization options.


chrubuntu 12.04 lts stopped working need help?

Chrubuntu uses a special kernel since it is having to run on top of ChromeOS which has a custom ChromeOS Linux kernel. The newer Chromebooks don't have this problem and can use a PC bios which makes it easier to use a standard Linux kernel. Here are a few more details on why this is so...

http://chromeos-cr48.blogspot.mx/2013/10/chrubuntu-for-new-chromebooks-now-with.html


No brightness control 18.04 LTS: /sys/class/backlight is empty

xbacklight does not work for you, right?

In my case a workaround is use the line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nvidia.NVreg_EnableBacklightHandler=1"

in the /etc/default/grub file.
The problem is explained here


Restore accidentally with rm'ed pam.conf?

I just copied the files '/etc/pam.conf' and '/etc/security/pam_env.conf' and the folder 'pam.d' from the Ubuntu Installation Disk.


Why do I get a blank screen when booting from a CD or USB stick?

It sounds like you've copied the ISO image to the USB stick and CD.

You need to create a bootable CD/USB stick rather than simply copy the ISO image.

There are instructions on the Ubuntu web site explaining how to create bootable media.

Scroll down to 2 Burn your CD or create a USB drive and click on Show me how.


Installer crash; problem can't be reported

Please make sure you get all your installations from official Ubuntu Sources before installing. Whether or not a crash report makes it back to Canonical is not going to help you complete the install. Try the official installs, and let us know how it went.


Is my HP DeskJest 1512 All-In-One printer compatible with Ubuntu 14.04? How do I install it if it is?

You can find the answer to almost all of your printing troubles if you include cups, Common Unix Printing System) in your queries.

If you look at the cups feature summary for your model, you will find that it supports all the major features with the hplip package.  Your DeskJet will work pretty much out of the box.

You find the cups administration interface in your web browser at localhost:631. (The form here does not allow linking to localhost).

A nice troubleshooting guide is set up by the good folks at ubuntu.  I recently used the tail -f /var/log/syslog command when plugging in a finicky HP printer, only to find the solution to my problem written verbatim in that output.

NoviceUserFrance was nice to add that SimpleScan is a very easy to use scanning tool for your scanning needs.


Ubuntu Server 18.04 does not boot in legacy mode in Lenovo SR650 Server

I have one machine that will only install with one hard drive in it. Then I shut it down, insert the other disks and boot into the bios and set the installed disk first in the boot order , otherwise it will not boot.


What's the best way to Natty Narwhal 11.04 upgrade?

If you don't want your data to be erased, the best option is to update it via the Update Manager.
It will not be the same look since from version 11.04 Ubuntu ships with a new Desktop Interface 'Unity'. It will not look like the Gnome Desktop Environment, your current Ubuntu (10.10) have.


How do I hide the IP & port in my URL in the browser?

Just make mysite.com resolve to 45.40.45.40. Then connect to http://mysite.com:9999 from your browser. There is no redirect needed. Also no need to change anything in your router or apache configuration.

If you want to hide the port number as well you have to replace the redirect you originally did with a reverse proxy. That would be some server (apache, nginx, ...) that listens on port 80 and proxies the request to the real web server. All requests will always go through this reverse proxy. There are already answers how to set up reverse proxies, e. g. this:

Nginx reverse proxy and subdomains

However, the effort to do this is quite high and all you gain is that you have a few characters less in your URL.


I can't comment, but if you did a reinstall it is unlikely anything you did with the driver is affecting you now (unless you somehow produced a hardware problem).  However, my enthusiest-level understanding of how hardware works makes me think it unlikely that anything you were doing with your HDMI port would have affected your Wifi without damaging a lot more than the Wifi... and indeed the likelihood of any harms seems pretty low.  If you are reinstalling, you probably are reinstalling a different version or are downloading newer/updated packages than you had present on your system before.

On the basis of that conclusion, I'd say that you are best of debugging and treating your wifi issue as separate from any of your pre-re-install activities.  Do you know what type of chipset your wifi is using?  Are you sure you have the support packages installed?  Have you gone through the steps here: https://help.ubuntu.com/stable/ubuntu-help/net-wireless-troubleshooting.html ?


Juju Local failed with /var/run/dbus/system_bus_socket: No such file or directory

Found this question:

juju bootstrap fails on local environment - Could not install mongo service

sudo apt-get install dbus


eTurboTouch does not work on Xubuntu Focal Fossa

Trying to be a good citizen, I did my research, and as often, solved my own problem in the process.
I posted my question (and this answer) anyway, hoping it may help some desperate soul (possibly myself) in the future.
The vital clue same from this command:
$ sudo libinput list-devices | head -n1
event5  - eTurboTouch eTurboTouch: libinput bug: missing tablet capabilities: btn-stylus resolution. Ignoring this device.

I googled the error message, and found out this wasn't the only touchscreen having this issue:
https://bugs.launchpad.net/ubuntu/+source/libinput/+bug/1772083
From the bug description:
*** Creating the following udev rules file, fixes the touchscreen for me ***
/etc/udev/rules.d/91-libinput-egalax-local.rules
ACTION=="add|change", KERNEL=="event[0-9]*", ENV{ID_VENDOR_ID}=="0eef", \
ENV{ID_MODEL_ID}=="0001", ENV{ID_INPUT_TABLET}="", ENV{ID_INPUT_TOUCHSCREEN}="1"

I adjusted it slightly to fit my situation.
I created a new file /etc/udev/rules.d/91-libinput-eturbotouch-local.rules
and put the following lines in:
ACTION=="add|change", KERNEL=="event[0-9]*", ENV{ID_VENDOR_ID}=="22b9", \
ENV{ID_MODEL_ID}=="0008", ENV{ID_INPUT_TABLET}="", ENV{ID_INPUT_TOUCHSCREEN}="1"

After a reboot, the touchscreen worked perfectly fine.
Notes:

The vendor and model ID (22b9 and 0008, respectively) are based on the output of lsusb, as seen in the question.
I rolled back my earlier changes to force-load hid-multitouch. The module is still not loaded by udev, but apparently, my touchscreen does not need it.


Thank you for sharing useful hardware specifications.
Unfortunately you are having very "dated" hardware.
Most relevant is the very small amount of the RAM.
This is the main reason why the boot time is slow.

More important is the overall performance of the system.
You should consider to install the light-weight Xubuntu.
Alternatively you can replace the 2x1 GB with 2x2 GB.
But it is not really recommended for this "old" PC.


Why is disk usage greater than the size of all files on it?

Files on disk have two sizes: the  "apparent size" and the "size on disk". Several reasons can cause a large discrepancy:

A large number of files will result in a large amount of overhead, because of internal fragmentation. E.g. Ext4 has a 4KiB default block size; files smaller than that will consume always 4KiB, and sizes above will be "rounded" to this block alignment.
Directories are also files and the same rule applies for them as well. Moreover, if you would create a large amount of files in a directory, and remove them again later, the usage on the directory file can't be reclaimed (recreating the directory helps).
Sparse files are special files, that appear to be large, but aren't 'consuming' the space. This is common in virtualization for virtual disk images; they will appear large, but the 'real' size can be a lot smaller. A lot of utilities (and file managers) are incapable of showing the actual disk usage.
The use of hard links. The contents of a file can exist on disk while multiple references are pointing to it. Some file managers may account the size for every reference.

I would suggest to use a disk usage tool known to be capable of listing both sizes to see if this is the issue. Try ncdu in a terminal and use a to toggle between actual and disk usage.

A short demo on internal fragmentation due to a 4KiB block size filesystem using du:

$ sudo tune2fs -l /dev/path-to-device | grep "Block size"
Block size:               4096

$ echo blaataaap > myfile                      # creates a 10-byte file

$ du --block-size=1 myfile                     # prints the usage on disk (filesystem)
4096   myfile

$ du --apparent-size --block-size=1 myfile     # prints the apparent size, i.e.
10     myfile                                  # content length when seeking

$ ls -al
-rw-rw-r-- 1 gert gert 10 Jan 1 23:24 myfile   # ls uses apparent sizes

This means that this 10-byte file is 4086 bytes bigger on disk than it would appear in a listing and is suffering from internal fragmentation.

A short demo on hard links and disk usage shown wrong when listing files (ls in this case):

$ dd if=/dev/zero of=1MBfile bs=1M count=1 # create a 1MB file
$ ln 1MBfile a_hard_link                   # create a hard link to it

$ ls -alht                                 # ls will report 2MB
total 2.1M
drwxrwxr-x  2 gert gert 4.0K Jan  2 11:21 .
-rw-rw-r--  2 gert gert 1.0M Jan  2 11:21 1MBfile
-rw-rw-r--  2 gert gert 1.0M Jan  2 11:21 a_hard_link

$ du -B 1024 .                             # du reports 1028K total for directory
1028    .

$ du -B 1024 a_hard_link                   # and 1024K for each file individually
1024    a_hard_link
$ du -B 1024 1MBfile
1024    1MBfile


The hostname is the IP address of the machine MAAS is installed on. In the terminal on the MAAS machine run ifconfig and find the IP address for that device. Then replace hostname above with the IP address.


/ssh is not a valid file path, and if it is you don't have access to view it.

SSH Keys are usually generated and placed into $HOME/.ssh/.  I think you meant to run this:

ssh -i $HOME/.ssh/id_rsa root@x.x.x.x


/etc/shadow file permissions keep resetting on ubuntu server

You could use auditd to find the process that is changing the permissions:

sudo apt install auditd
sudo auditctl -a exit,always -F path=/etc/shadow -k "etcshadow"
[wait until permissions changed]
sudo ausearch -i -k etcshadow

This will install the auditd package and register an auditing rule for /etc/shadow under the name etcshadow. The last command is to search the audit event database for entries created by the previously registered rule.


Error while installing extension pack on Oracle VM VirtualBox

with out knowing what is in the script we cant help you much better. Any way you are trying to install extension pack and you can do it by downloading from VirtualBox .

click here to start download

Then open it with virtualbox. It will install automatically there after.

Hope that helps.


You can reset any gsettings key to its default value by gsettings reset ....
So in this case run

gsettings reset org.gnome.desktop.wm.preferences focus-mode

Alternatively, run

gsettings range org.gnome.desktop.wm.preferences focus-mode

to get the all possible permitted values and set the one you like by

gsettings set org.gnome.desktop.wm.preferences focus-mode <your-choice>


A quick and dirty solution.

I downloaded and installed four quickly_12.08.1.deb built files in Ubuntu 16.04 from: https://launchpad.net/ubuntu/+source/quickly/12.08.1-0ubuntu2/+build/3854610

The files were:

python-quickly-common_12.08.1-0ubuntu2_all.deb
python-quickly-core_12.08.1-0ubuntu2_all.deb
quickly-ubuntu-template_12.08.1-0ubuntu2_all.deb
quickly_12.08.1-0ubuntu2_all.deb

I installed the four above using gdebi.
I also needed gedit, glade and glade-gtk2.

That enables to:

quickly create ubuntu-application foobar
quickly run
quickly design
quickly edit

Note:
You must be in 'foobar' folder to run, design and edit.

To get quickly package to run, I had to install these:

apt-get install build-essential autoconf automake autotools-dev dh-make debhelper devscripts fakeroot xutils lintian pbuilder

It's not pretty, but it works and produces a functioning .deb application that can be installed and removed using gdebi.

An alternative option:
Run Ubuntu 14.04 in a virtual machine (I used VirtualBox), then load quickly as normal:

sudo apt-get update && sudo apt-get upgrade
sudo apt-get install quickly quickly-ubuntu-template

Note:
You can then produce a .deb package from Ubuntu 14.04 that also works in 16.04 (I used gdebi to install and remove them).

Also:
I needed to install vbox-guest-additions of the same revision as my host app to get full screen resolution.


Execute command from file in current shell

Use builtin command source (from help -m source):

  source - Execute commands from a file in the current shell.

Example of execution mentioned in Question:

pandya@pandya-desktop:~$ source ch_dir
pandya@pandya-desktop:/usr$

Here you can see cd /usr is executed in current shell and hence directory of current shell changed!

Hope this will help to execute command input from file in current shell.


Seems that your 16.04 kernels are not patched for spectre/meltdown.

In my understanding kernel 4.4.0-109 contains partial patch, you are running 4.4.0-97 that have not mitigated any actions towards addressing side-channel attacks, thus delivering better performance.

Is it wise to run those on SMP production system - completely different question...


The problem is that the uninstall script is trying to stop the "avgd" service so that it can be uninstalled. However, the script fails and aborts if the service is not actually running at the time! You can either try to get the service to run so that it can stop (I failed at this) or you can edit the AVG supplied uninstall script.

On my system, the "pre-remove" file avg2013flx.prerm was in /var/lib/dpkg/info/.

sudo nano /var/lib/dpkg/info/avg2013flx.prerm

Or use whatever editor you are comfortable with and comment out or remove the lines that look like this:

if which invoke-rc.d >/dev/null 2>&1; then
    invoke-rc.d avgd stop
else
    /etc/init.d/avgd stop
fi

Save the file and sudo apt-get purge avg2013flx should work to remove the package from your system.


Cannot play *.mp4 - files in Ubuntu 18.10

Have you tried installing the restricted extras package? That normally covers most non-free media formats.

The command to use is:

sudo apt-get install ubuntu-restricted-extras

Full instructions here: https://help.ubuntu.com/community/RestrictedFormats


Program to balance speaker output for surround sound 2.1?

Install pulse audio volume controller.

Open up your Terminal and execute these commands:

  sudo apt-get install pavucontrol
  pavucontrol


I did it with the following command:

sudo apt purge code

to uninstall the program and then:

sudo apt autoremove

to remove the menu items/shortcuts etc as @Joe suggested.

I hope it helps!


What sort of information do I need to send a bug report to nouveau developers?

The /Bugs wiki page on the Nouveau wiki at freedesktop.org says:

  Attach complete, unfiltered, untrimmed kernel log from boot up to
  the problem, and a complete X log if
  the problem manifests with X
  Please, do not compress files you attach to bug reports, especially
  plain text files such as logs, unless
  the file is so huge bugzilla refuses
  to take it. Gzipping files makes
  taking a quick look impossible
  Make sure the mime-type of text files really is set to
  text/plain, and not e.g.
  application/octet-stream. This makes
  life a little easier for people
  reading bug reports. The point is to
  let people read text files directly in
  a web browser.


Add to the top of the /etc/ufw/before.rules before the *filter (top of file):

*nat
:PREROUTING ACCEPT [0:0]
-A PREROUTING -i eth0 -p tcp --dport 2222 -j DNAT --to 10.0.3.11:2222
COMMIT

then restart/reload the firewall

sudo ufw disable && sudo ufw enable

Since we're using other that ufw's chains ufw-before-*, ufw-after-* and ufw-reject-*, we have to change MANAGE_BUILTINS=no to MANAGE_BUILTINS=yes in file `/etc/default/ufw. Check this post for more details.


Currently, Flash does not use Pulseaudio, this is a known issue. PulseAudio developers need to rely on Adobe's support to fix this.


You wrote:

  Recently installed Ubuntu 14.04 along with windows 8.1 in my dell inspiron 15 5547 (Legacy Mode, windows 8.1 in uefi mode)

Your parenthetical comment reveals the cause of the problem. Mixing BIOS/CSM/legacy mode and EFI/UEFI mode is a Bad Idea. On most computers, doing so makes it difficult to switch boot modes.

Fortunately, the solution is not too difficult: Install an EFI boot loader for Linux. Several are available (see the preceding link), but two are likely to be easiest to install and maintain:

rEFInd -- Download and prepare a USB or CD-R image of my rEFInd and boot with it. It should detect both Windows and Ubuntu. Test booting both OSes. If both work, boot to Ubuntu and install the PPA or Debian package version of rEFInd. It will then take over as your default boot manager, and you'll be set.
EFI-mode GRUB -- GRUB is Ubuntu's default boot manager, but you've got the BIOS/CSM/legacy version installed. You must replace this with the EFI-mode version. This is most easily done by booting an emergency disc to EFI mode and running Boot Repair (in the boot-repair package, IIRC). The trick is booting to EFI mode. You may need to use rEFInd (as above), or you can disable BIOS/CSM/legacy support in your firmware and boot your Ubuntu installation disc to its "try before installing" mode, or you might be able to use your built-in boot manager to boot the installer to EFI mode.

The biggest problem you face is variability from one EFI to another. This variability means that there is no standardized way to get to the firmware's built-in boot manager, force an EFI-mode boot, and so on. There are also bugs that can interfere with one or both of these solutions. You'll just have to take these issues one at a time as you work toward a solution.


Dual Monitor app windows moved after unlock

This is not exactly a solution, but a work around to the problem:
Go to Settings -> Brightness & Lock

Turn off 'Lock',  and unselect 'Require my password when waking from suspend'

This will stop the screensaver lock screen from interfering with your desktop window layout in a multiple monitor situation.

Tested on Ubuntu 16.04


sudo: can't open /etc/sudoers: Permission denied

Can you change directory to /  ? being in root user? May be you are missing permission to this path / as root

See https://unix.stackexchange.com/questions/39328/sudo-cannot-open-etc-sudoers

http://arstechnica.com/civis//viewtopic.php?t=1170439


how to access Nextcloud (running on a local machine) from outside?

so, the first part works and was quite easy to achieve.

the ASUS router has a built-in DDNS service and pointing that to my no-ip.com account plus setting up port forwarding (80:80, 430:430, 8080:8080 for the moment) did the job.

So for now I regard this matter as solved, thanks


Problem Installing ubuntu via usb in ASUS R510C

"go to Boot in BIOS and enable the option Laucnh CSM and sub option Launch PXE OpROM."

from http://tomshardware.co.uk/forum/324872-30-boot-bios-asus-x501a


Splitting a large text file every x pattern repeats

Here is a small perl script for you. You can save it as split_files.pl and run it as perl split_files.pl input.txt. The output will be stored in files called chunk_0, chunk_1 etc.

#!/usr/bin/perl
use strict;
use warnings;

my$infile=shift(@ARGV);

my$linecount=0;
my$filecount=0;
my$outfile="chunk_".$filecount;

open(IN,'<',$infile) or die $!;
open(OUT,'>',$outfile) or die $!;
$/="\n>";
while(<IN>)
{
    chomp;
    $_=~s/>//g;
    if($linecount==100)
    {
        $filecount++;
        $outfile="chunk_".$filecount;
        close OUT or die $!;
        open(OUT,'>',$outfile) or die $!;
        $linecount=0;
    }
    print OUT ">",$_,"\n";
    $linecount++;
}
close OUT or die $!;
close IN or die $!;

Explanation:
The trick of the script is the line $/="\n>";. This line changes the default linebreak charachter (\n) to a "newline+>" (\n>). In the while-loop, each block beginning with ">" is used at once. I used two counting variables ($linecount and $filecount). The lines (or blocks in this case) are counted and when this count hits 100, a new file is used for the output.


Cannot disable IPv6 Autoconf and Privacy Extensions, but sysctl values are set to disable it

For reasons I am unclear about, I found that netplan needed an explicit configuration for accept_ra regardless of what was set in sysctl values, for example:
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      accept-ra: false
      addresses:
        - xxx.xxx.xx.xx/22

And apply the new config with netplan try. No reboot was required.
I was using Ubuntu 18.04 but I assume 20.04 would be the same.


You can install Sphinx directly from a clone of the Git repository or simply installing directly via pip pointing git repository url.

git clone https://github.com/sphinx-doc/sphinx
cd sphinx
pip install .

or

pip install git+https://github.com/sphinx-doc/sphinx

If you use python3.

pip3 install git+https://github.com/sphinx-doc/sphinx


Why isn't Google Chrome available in the Software Centre?

Because Google Chrome contains non-free parts (internal PDF, Flash and media support)
As you may know, the Chromium browser is available in Ubuntu Software Center. Google Chrome is built from the same source code as Chromium, but includes some additional features which make it impossible to distribute via Software Center/the official repositories.
Specifically, it includes proprietary PDF/Flash plugins as well as support for AAC/MP3/etc. formats. These components are non-free (no source-code available), so Ubuntu's policy forbids distributing Chrome via the Software Center/repositories.
Chrome also requires agreement to a restrictive EULA (license)
Additionally, while Chromium/the source has a free license (BSD), Google requires you to agree to a much more restrictive "End User License Agreement" (EULA) to download and use Chrome.
Google forbids third-parties from distributing Chrome
I believe Google also prohibits anyone (or any site) from redistributing the full Chrome; that's why the "portable Chrome" packages you find will download Chrome from Google when you install them, instead of including it. Even Download.com only gives you the tiny installer which downloads Chrome from the Google servers.
Solution: download it, or use Google's PPA
The solution if you must have Chrome, as the other answers have explained, is to download Chrome or install it via Google's own PPA


Ubuntu iso file not showing up on file after downloading from the Select button on Rufus USB creator

What is the extension of the file you downloaded? Are you sure you really downloaded  the .iso and not the .iso.torrent (which is just the torrent metadata that you need to use the download the ISO). Rufus will only list files that have .iso, .img and a small list of other extensions. If your file doesn't have a .iso extension, it will not show up by default in Rufus. You need to be able to tell us what extension your file has if you want to get help.

What is the size of the file you downloaded? If it's less than 2 GB then either it's corrupted or you downloaded the wrong file. You need to be able to tell us the size of the file you downloaded if you want to get help.

Be mindful that, as opposed to File Explorer, Rufus runs with elevated privileges, which means that, in some circumstances, it may not be able to access the same folders or see the same data as the standard user. For instance, if you downloaded the ISO to a network share, then Rufus might not be able to access it.


XPS15 fails to suspends after upgrade to ubuntu 17.10

I had similar problem. The system won't shutdown after upgrade to 17.10. I shifted to earlier stable version of kernel from grub at startup, and now everything works fine. I am currently using 4.10.0-37-generic and was facing problems on 4.13.0-16-generic


Incompatibility between WP super cache and PHP APC?

Been looking around for some more technical explanation of this.

I don't believe this problem is Ubuntu related.  I've seen similar Wordpress WSOD crashes... APC, WP Supercache, Apache, FreeBSD.  Site(s) would run reliably for some period of time then WSOD all of a sudden.

Apache restart (which would flush APC cache in memory) fixed the issue.

Turning off SuperCache fixes the issue.

SuperCache probably has some obscure bug with APC...character encoding bug?


Logged out right after login after docker install

So it turns out that when I installed the packages with docker it messed up something with my graphics driver (not sure how). After re-installing my graphics drivers everything seemed to work fine.

here is where I found a solution that actually worked: login loop after upgrade to 16.04


As a temporary solution, try creating a new user account and logging in from there, or log in to a Guest session. Those problems are usually associated with broken configuration files in your home folder, so a new user account should load just fine.


How to split screen into two independent areas?

Possible solution:

Use a tiling screen manager (such as xmonad or my personal favourite, spectrwm).

This allows you to run applications in an area and automatically tile them (like the Windows 'Stack windows horizontally' feature). Because the areas have sections, multiple programs can be run under each area including in full screen mode without obstructing the view of the others.

As far as mouse locking goes, I can't find a way to stop the mouse from going between areas, but you can stop the focus from being changed when the mouse moves (such that the area will only "switch focus" upon a keyboard shortcut combination). To achieve this, edit the .spectrwm.conf (the config file for spectrwm) in your home directory so that the line:

  #focus_mode = default

is changed to

  focus_mode = manual

Cons:

Can't use Unity sidebar (although someone might have a way around this)


14.04--Routine update killed network-manager, unable to connect to any networks

I could recover from the same problem by downgrading to the following packages (assuming the 64-bit version):

libnl-3-200_3.2.21-1_amd64.deb
libnl-genl-3-200_3.2.21-1_amd64.deb
libnl-route-3-200_3.2.21-1_amd64.deb

From a device with internet access download the above packages (e.g from packages.ubuntu.com) and find a way to transfer them to your computer.
Install them with

    dpkg -i *.deb

After a reboot everything should work again.


How can we claim drivers without Internet?

In our chat, we searched your system for the correct driver iwlwifi. We found that it was present in kernel versions 4.15.0-36 and -38 but not the kernel version you were then running, -39.

I suggested that you interrupt the boot process at the GRUB menu and, under Advanced options for Ubuntu, select -38 to see if the wireless was then working as expected. It was.

I suggested that you allow Update Manager to run and update your system, hoping that an even newer kernel version would be installed. It was, that is, 4.15.0-43. When you rebooted into -43, the wireless also worked as expected.

Since the iwlwifi module didn't exist in -39, but did in -38 and -36 and, obviously, in -43; I suspect that the update to -39 went wrong somehow; the correct driver(s) were not properly installed. A clue was given in your original comments: "Also, when I run lshw in terminal, there are several other unclaimed devices. Here's which: display, generic 0-4, communication, network, memory, multimedia, serial, and volume 0." Evidently, many other drivers were not correctly installed.

I am glad your wireless is now working as expected.


Can I get a package from a ppa that my distro doesn't support?

This a simple way for app's that don't need any source modification. I think this better when having many packages, instead of building all them locally (with many dependencies headache)

Get a Launchpad account.
On your user page, Create a new PPA

Input url you want, display name, then activate
Open PPA page of the wanted App → View package details
At top right corner: Copy packages

Source: Select packages you want. If there are multi-releases for same package, choose the closest to the target release.
Destination PPA: PPA you just created.
Destination series: target release.
Copy options: Rebuild the copied sources
Copy Packages

If it's built without problems, few minutes it will be ready for download from your PPA.


python-nltk on Ubuntu 12.04 LTS: nltk.download('brown') results in HTML error 401

The DEFAULT_URL used in downloader.py of the Ubuntu packaged version still uses:

DEFAULT_URL = 'http://nltk.googlecode.com/svn/trunk/nltk_data/index.xml'

But the current data server is:

DEFAULT_URL = "http://nltk.github.com/nltk_data/"

You can of course install from source or... modify your already installed version to point to the new server like this:

 sudo perl -pi -e 's#DEFAULT_URL = .*#DEFAULT_URL = "http://nltk.github.com/nltk_data/"#' /usr/lib/python2.7/dist-packages/nltk/downloader.py

You can then install the "brown" corpus:

$ python
Python 2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import nltk
>>> nltk.download('brown')
[nltk_data] Downloading package 'brown' to /home/sylvain/nltk_data...
[nltk_data]   Unzipping corpora/brown.zip.
True
>>> from nltk.corpus import brown
>>> brown.words()
['The', 'Fulton', 'County', 'Grand', 'Jury', 'said', ...]
>>>


How do I download qt5-default for Ubuntu 20.04 LTS?

This would be a one-liner in Terminal, but let's make sure you're updating apt first:

Update apt:
sudo apt update

Install qt5:
sudo apt install qt5-default

There is no step 3

That should do it for you


First of all, yes, you won't be able to use a bridged network connection because all of the guests will have the same hostname, so you'll have to go with NAT.
You got part of the configuration right, however, your problem should be in the default gateway that you assigned to the guest. The default gateway, when using NAT, is not the IP of the host, it's the IP of a "virtual switch" that's connected to the NAT network. (The host VMnet8 adapter is merely another device connected to the network, to allow the host to communicate with the VM.) This virtual switch we're talking about gets the .2 IP in the subnet. So in your case, your /etc/network/interfaces should read:
auto eth0
iface eth0 inet static
     address 172.241.0.101
     netmask 255.255.0.0
     gateway 172.241.0.2

This should grant your guest VM access to the internet (through 172.241.0.2), and also communicate with your host (172.241.0.100). So try it out and let me know if it works.
If it doesn't work (highly unlikely), then you need to find out what the IP of the virtual switch is. What you can do is let the VM get an IP through DHCP (i.e. change it to iface eth0 inet dhcp like you had it before), and then do route -n. This should show you the default gateway it's using. Use that IP in your static configuration.

To be able to ping the guest VM using its hostname Workshop, here's what you can do. You need to add an entry in the hosts file in Windows, which is located in C:\Windows\System32\drivers\etc\hosts. Edit that file to include the following line in the end:
To edit that file under Windows however, you need to open it as an administrator in Notepad or Wordpad...and sometimes it doesn't even let you save it, so you'll need to take a copy of the file somewhere, edit it, remove the .txt extension if it got one, and go back and replace the original one, and "confirm" it...oh how I love Linux. But anyways, here's the line you need to add:
172.241.0.101    Workshop

Once this is done, you should be able to ping Workshop successfully from your Windows host.
Though of course, to be able to deploy this in your workshop, you'll need to edit the hosts file in every single Windows host, unless you're also cloning the Windows machines.
Tip: since you're going to assign a static IP to your guest, make sure that the "NAT network" in VMplayer on all of your Windows hosts are using the subnet 172.241.0.0/16, because I think VMware randomly assigns a subnet to its virtual networks (VMnet1, 2, and so on), so VMnet8 might not be using the same subnet on another Windows host. If they're not, you'll need to manually give VMnet8 a subnet using the Virtual Network Editor in VMware.

EDIT
Okay. After the comments, here's what you need to do:

Configure your (Windows) host machine to "obtain IP address automatically" on the VMnet8 adapter. It should get the IP 192.168.186.1.

Configure your (Ubuntu) guest machine to a static IP in the range 192.168.186.3 - 192.168.186.127. Let's use 192.168.186.3. Also, configure the default gateway and dns server to be 192.168.186.2 So your /etc/network/interfaces should be:
auto eth0
iface eth0 inet static
     address 192.168.186.3
     netmask 255.255.255.0
     gateway 192.168.186.2
     dns-nameservers 192.168.186.2

Test local connectivity by pinging 192.168.186.1 and 192.168.186.2 from the guest machine. You should also be able to ping from the host to the guest.

Test internet connectivity in the guest machine by pinging google.com, or browsing the internet.

Add the line 192.168.186.3    Workshop to your hosts file in the Windows host machine.

Test ping Workshop from the Windows host machine.

If you want to use IPs from an altogether different network/pool other than 192.168.186.0/24, you'll need to go to Edit > Virtual Network Editor in VMware, find VMnet8, and change its DHCP settings at the very bottom to whatever network you want, and change the static IPs accordingly (the default gateway will always be the second usable IP, x.x.x.2).


After format, unknown filesystem on boot, bootable usb cannot mount /dev/loop0 goes to initramfs

After a discussion in a linked chat room, the problem was solved.

There was an error on the live USB stick, and you found it by running 'Check the disk for defects' from the boot menu. It appears that this error was preventing loading the filesystem on the bootable USB stick.
Downloading a new image (Ubuntu 18.04.4) and flashing the image onto it (this time using Etcher 1.5) resulted in a bootable USB stick that allowed to reinstall Ubuntu.
Running Ubuntu live booted from the USB stick, it was possible to format the HDD, thereby restoring the faulty partition.


I had the same issue (described in bug #728745) and I successfully solved it after activating the nvidia-173-updates driver in the additional drivers preferences (as suggested in this comment). It is said to disable hibernation and multiple screens.

Note that a newer driver version is mentioned in the bug thread (version 275.43, see comments #144 and #145) that is said to fix everything, but I was reluctant to try it, because it has to be installed manually (you have to disable Nouvau, exit X and run it from a terminal) and in the future updated manually (through the nvidia-installer program) and who knows how this might play with future Ubuntu updates. Anyway, 173 works fine for me for now, so if it ain't broken, don't fix it :)


Leap is still set up for upstart, and the recent move from upstart to systemd make some packages like Leap failed to install.

Follow the steps below:

sudo nano /lib/systemd/system/leapd.service
sudo ln -s /lib/systemd/system/leapd.service /etc/systemd/system/leapd.service
sudo systemctl daemon-reload
sudo dpkg --install Leap-2.3.1+31549-x64.deb

leapd.service file:

[Unit]
Description=LeapMotion Daemon
After=syslog.target

[Service]
Type=simple
ExecStart=/usr/sbin/leapd

[Install]
WantedBy=multi-user.target

After installation, you can see:

Check Leap Motion daemon with: service leapd status
Open the Leap Motion GUI with: LeapControlPanel
See /usr/share/Leap/README.linux for more information

Source


Are the following programs working in PlayOnLinux?

Using linux means using free/open source software. There are workarounds like wine (or playonlinux) and virtualbox to install windows programs, but they are limited. Wine/Playonlinux has limited support of applications (means not all will work), whereas in virtualbox they will work (you basically create a windows virtual machine), but you will need some RAM memory to run fine. If you have 2GB of memory, you set 512MB or 1GB for your virtual machine and it should be fine.

If you desperately need these windows programs, then create a virtual machine in virtualbox, install windows there and enjoy your programs as they are meant to be used.

On the other hand, you can check with your professors and discuss the possibilities of free software alternatives:

Instead of Visual Studio 2010 you could try Mono which is cross platform - you can install the package using the ubuntu software center.
Instead of Microsoft Office 2007/2010 you could try out Libreoffice, preinstalled in Ubuntu. You have an option to export documents as PDF, so that everyone can read them.
CorelDraw x5 - Try installing gimp and gimp-data-extras  Inkscape, Karbon or Sk1 packages from ubuntu software center
YahooMessenger 11 - Try Pidgin or empathy


Can't change default shortcut behaviour in gnome

The settings panel is buggy: setting a default shortcut to a new behaviour won't change the shortcut. It will still perform the old behaviour.

To correct this:

Open the dconf editor by typing dconf in the Activities search
bar.
Go to org>gnome>desktop>wm>keybindings
Find the old behaviour
Uncheck Use default value and remove the shortcut you want to use from the Custom Value field. (Syntax is ['<Modifier>Key1', '<Modifier>Key2']
Define your shortcut on the new behaviour.

For example: I removed '<Super>Up' from the maximize behaviour and defined ['<Super>Up'] as the custom value for the switch-to-workspace-up behaviour.


Ubuntu 17.10 Freezes on Suspend/won't shut down

If you have EasyScreenCast gnome extension installed - try to remove it.
About that exact error i saw comments on launchpad in which peoples said that EasyScreenCast deletion solved problems for them (and with my own experience - recently installed it and all my system become deadly frozen - so have to remove it from terminal in recovery mode).

Another thing to try is to switch between display managers - from gdm3 to lightdm, for example. Run sudo dpkg-reconfigure gdm3 (install lightdm before via sudo apt-get install lightdm if needed). Recently had same log error, after switching from gdm3 to lightdm error had gone.


How to get a 3 screen setup working- what hardware?

For a new desktop computer you would want an Eyefinity enabled video card.

I personally use an XFX HD 5870.

Most, if not all, video cards that support three monitors will require either one monitor to have a Display Port (read: Very expensive monitor) or you to buy an active display port adapter. Those run around $90. Passive ones will not work.

So yeah. What you're looking for is an Eyefinity enabled ATI video card. Even the ones with two DVI ports, one HDMI port, and one DisplayPort will require one of your monitors to be hooked up to the display port because it can't pull power from the 3 others at the same time.

EDIT: Also, any of these cards should be beyond powerful enough to support Compiz.


How to enable services Discovery API in GoogleCL?

This workaround involves NOT using the .deb packaged GoogleCL:

/usr/local/src/googlecl-read-only/build/scripts-2.7/google tasks tasks list

was the alternative binary from svn that supported Services Discovery API.  The example above tests the "Google Tasks" cli which is beyond the initial seven services supported by the Ubuntu distro GoogleCL.


Assuming you have their consent, I can't see why you don't just use TeamViewer.


The easiest way is to use alt+F2 the type 'r' and enter.  This re-starts gnome-shell in the least destructive way.

Then go to System Settings keyboard click on the shortcuts tab and verify that your shortcuts are there.  Any you have defined are in the custom shortcuts section.

If not there, set them up again, close system settings and try each of your shortcuts.


Why Clamtk is not scanning anything as well

The clamtk settings may not be selected correctly. By default, some settings may be disabled and you may have to activate them as below. Please check Configuration -> Settings menu for the items below and activate them by ticking/selecting;

tick -> scan files larger than 20 MB
tick -> scan directories recursively


USB to HDMI adapter that works with 20.04

I have heard that USB-to-video adapters using DisplayLink GPUs have Linux drivers and work well enough.  I say "well enough" because USB was not built to support computer displays, it's something of a hack to use USB for this.
If your laptop has a DisplayPort or HDMI output, and I suspect it does as not having a video output on a laptop is rare, then getting an adapter for one of those to VGA should be more stable, give better performance, and not need driver updates with each new OS upgrade.  Avoiding the use of VGA would also be wise but I can understand the need to keep using it in some cases.  I've used DisplayPort to VGA adapters before and found them inexpensive and "there is no step three" simple to use.


Newbie - Downloads slow on wireless, long time to connect to wireless

Are there other wireless devices nearby which use the same WiFi frequencies, but which are not WiFi? Wireless game controllers and wireless headsets are infamous for causing this, but baby monitors and 2.4GHz cordless phones can cause this as well.

Also try changing the frequency used by the wireless router. Typically, 1, 6 and 11 are the best to use.


I have had this same problem a few times with kile (kate with other tex feature). If the line is too long (or any other thing it doesn't like) it comes up with a stupid error and you need to change the settings. After this, it sets the file into read only mode when you open it again. Check the tools menu, it may have the read only option switched on.


Unable to change brightness in a Lenovo laptop

If the GUI tools fail, try to use the terminal for it.

Open a terminal
Run: ls /sys/class/backlight/*/brightness. Example output would be:

/sys/class/backlight/acpi_video0/brightness

If nothing is found, the kernel does not support brightness control (missing drivers?). Otherwise, you can use the below commands (replace acpi_video0 accordingly):

Get the current brightness level:

cat /sys/class/backlight/acpi_video0/brightness

Get the maximum brightness level:

cat /sys/class/backlight/acpi_video0/max_brightness

These commands return brightness levels which ranges from zero to max_brightness (see above).
To change the brightness level, you need to write a number to the brightness file. This cannot be done by an editor like gedit. Say you want to change your brightness to 5, you have to run:

echo 5 | sudo tee /sys/class/backlight/acpi_video0/brightness

Alternatively, if you just want to set the brightness level to the highest available:

sudo tee /sys/class/backlight/acpi_video0/brightness < /sys/class/backlight/acpi_video0/max_brightness


Audio-recorder "start if sound" not working 14.04

Please file a bug-report on https://launchpad.net/audio-recorder.

It may help if you add time (in seconds) and an audio-level value.

Examples:

start if sound 0.4
start if sound 3s 0.4
start if sound 3s 40%

Please copy-paste all timer commands (text) to the bug-report.


Shell script to move all files from subfolders to parent folder

Go to your A directory and run

find . -mindepth 2 -type f -print -exec mv {} . \;

which means "find all files in this directory and its sub-directories and execute mv with target directory . for each file found to move them to current directory.


First of all gnuplot is packaged.

If you really want to compile it read below:

Do not forget to enable Source code repositories from Software & Updates aka software-properties-gtk (Ubuntu Software tab, check Source Code here).

Second for successful compilation you should install its build-dependencies with:

sudo apt-get build-dep gnuplot

Then you could clone gnuplot repository from Debian (Ubuntu upstream):

git clone git://anonscm.debian.org/debian-science/packages/gnuplot.git

And proceed as you already done. Last step may be checkinstall instead of make install.


Problem while installing katoolin in Ubuntu 17.10

Simply run this:

sudo bash -c "test -e /usr/bin/python || (apt -qqy update && apt install -qy python-minimal)"

Then run the command katoolin.


Grep Regex match not returning result as expected

Chances are you have a file that matches the glob pattern [0-9]* on your second machine, and not on the first one. If that's the case, the shell will expand the glob into the file's name before passing that as an argument to grep.

If there is no file that match on the current directory, the shell leaves the glob pattern untouched and passes it as-is to the command.

$ echo abc123 | grep -P -o [0-9]*
123
$ touch 234
$ echo abc123 | grep -P -o [0-9]* # shell runs grep -P -o 234
$ touch 123
$ echo abc123 | grep -P -o [0-9]* # shell runs grep -P -o 123 234
$ rm 234 123
$ touch 12
$ echo abc123 | grep -P -o [0-9]* # shell runs grep -P -o 12
12
$

Always quote parameters that contain shell wildcards if you don't want them to be expanded by the shell.


How do I boot into the console and then launch the Ubuntu desktop from it?

To return to the login screen
Press Ctrl+Alt+F7 to return to the login screen. You can exit your terminal session on tty1 by typing exit before you do that.
Doing startx -- :1 will start another X session under terminal tty1, logging you in directly (use :2, etc. for even more displays). Note that logging into multiple sessions as the same user is not recommended and could lead to system instability.

To skip the login screen completely, boot into the console and then start the GUI, you must modify GRUB:

sudo nano /etc/default/grub
Change line GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to GRUB_CMDLINE_LINUX_DEFAULT="text"
Ctrl-X, press Y and then Enter to save and exit.
sudo update-grub
Reboot and you should come up directly in tty1 -- no need to press Ctrl-Alt-F1.
Login, and then startx to boot into the default desktop, or

unity for Unity
unity-2d-shell for Unity 2D
gnome-shell for Gnome
sudo service lightdm start to get the login screen (if you fix it :)


R and RStudio installation and package error

I don't know why R 3.4.1 changes the library path. To change it back, simply edit /etc/R/Renviron:

$ sudo gedit /etc/R/Renviron

Comment-out R_LIBS_SITE=... then uncomment R_LIBS_USER=...

# edd Jun 2017  Comment-out R_LIBS_USER
R_LIBS_USER=${R_LIBS_USER-'~/R/x86_64-pc-linux-gnu-library/3.4'}

# edd Apr 2003  Allow local install in /usr/local, also add a directory for
#               Debian packaged CRAN packages, and finally the default dir
# edd Jul 2007  Now use R_LIBS_SITE, not R_LIBS
#R_LIBS_SITE=${R_LIBS_SITE-'/usr/local/lib/R/site-library:/usr/lib/R/site-library:/usr/lib/R/library'}


Edimax EW-7811Un wifi adapter not working on Ubuntu 14.04 LTS

This has been reported to work:

sudo apt-get install linux-headers-generic build-essential dkms
git clone https://github.com/pvaret/rtl8192cu-fixes.git
sudo dkms add ./rtl8192cu-fixes
sudo dkms install 8192cu/1.10
sudo depmod -a
sudo cp ./rtl8192cu-fixes/blacklist-native-rtl8192.conf /etc/modprobe.d/

Reboot

(Source)


What are the necessary packages for build , compile application and install it by creating make file?

Do you want to make a "make file" or compile it?

If it's for writing a make file: gedit or your preferred editor.

If it's for compilation, it's easy: gcc, g++, make, devtools (or maybe dev-tools or development-tools).


.sh file on Startup Applications isn't executed

Try putting them in a script and adding that script as the entry in your Startup Applications. It's hard enough to use environment variables and ~ in desktop files, let alone full-fledged command substitution, as evinced by Desktop Files don't seem to use $PATH correctly and How to include environment Variable in launcher for icon.


Unity Launcher is hard to access with auto-hide enabled

Try changing the Launcher Reveal Pressure.  The default is 20.  You might consider setting it at 1 and systematically try other settings to pick the ideal one.
You can get to this configuration through CCSM (the CompizConfig Settings Manager).
Click on Desktop -> Ubuntu Unity Plugin -> Launcher and change the 'Launcher Reveal Pressure'.
You may have to install it.  This can be done by:
sudo apt-get install compizconfig-settings-manager


PyGObject: Gio.File.copy_async() doesn't exist in Ubuntu 12.04

The reference manual you are quoting is not for python. I'm aware, that with gobject introspection, no python manual is available anymore (only a tutorial), but this manual does not document the python mapped functionality. A lot of functions from C have not been made accessible from other languages.

One way you might want to go, if you do not require Gio, is simply using python built-in functions?

The concurrent.futures module does things in an async way (backported here).
With that you should be able to do something like this:

import concurrent.futures
import shutil

with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:
    executor.submit(shutil.copy, "test1.txt", "test1_new.txt").add_done_callback(
      process_result )
    executor.submit(shutil.copy, "test2.txt", "test2_new.txt").add_done_callback(
      process_result)

More about this version here and here.


Application windows randomly blinking (see video)

I would login as with the Gnome interface for a while to see if it is Unity that is causing the issue.

It sounds like a video driver issue but it could also be a video memory issue. To rule those out if you run a custom video driver I would revert to the base driver.

If you still get issues with a base video driver and Gnome I would very likely assume its hardware.


When installing, how can I have multiple mount points on a single partition?

Install with just /home on the other disk, then boot into recovery mode, go to the root shell, and move those other directories to /home and replace them with symlinks to their new location in /home.

mv /var /home/
ln -s /home/var/ /var


Yes you can!
You qualify the minimum specs requirement.


Sharing files between a windows 10 and ubuntu PCs

Does the second HDD mount to something like /media/your-user-name/XXX.

If that is the case you need to force the client user to appear as "your-user-name". WHere you do that depends on how you created your shares. If it's through Nautilus then edit /etc/samba/smb.conf and right under the workgroup = WORKGROUP line add this one - substituting your real user name:

force user = your-user-name

If you created the shares directly in smb.conf you need to add that line to the share definition itself.

After editing smb.conf remember to restart smbd:

sudo service smbd restart


Broke Gnome Shell while trying to add a substitute themes folder-- now computer boots to a black screen,

Okay, so this is a problem solved.

Seeing as I hate it when people just go "PROBLEM SOLVED" in a forum leaving me wondering how they did it, I will elaborate for anyone who cares to know.

I ran sudo apt-get remove gnome-shell in TTY1 to remove gnome-shell, then followed up with killall -u username.

From what I understand, it was a bit like trying to unlock your door by throwing a nuclear bomb at it, but it successfully forced me back to the splash screen with no gnome-shell option, and Unity loaded safely and reliably.

I restarted (somewhat nervously) to see if it stuck. It did.

I'm giving this solution a tentative thumbs up, even if it was a little inelegant.


Allowing apache access to a subdirectory in a home directory without access to the home directory

You can leave your $HOME dir ownership alone. You don't need to set it to www-data. What you do have to do is ensure that Apache has execute permissions on $HOME and everything above it. So, you could do something like this:

chmod 751 "$HOME"
sudo chmod 751 /home

However, the fact that $HOME is encrypted might pose major problems for Apache unless you can somehow configure Apache to use the proper decryption key.

EDIT:

Setting execute permissions on a directory means only that you can access something inside the directory if you already know its name and if what you're trying to access also has correct permissions. So setting a global x-bit on $HOME isn't too much of a security risk, as long as all your other files have reasonable permissions. You might want to look into your umask to be sure.


Picking up radio station when connecting monitor on latop

Even if I agree that this is OFF TOPIC, for your case I suggest you grounding.

A good cable for grounding your system may lessen the interference/static but having your connections "in phase" will also do the trick. This can be caused if you are getting the POWER from different regulators/no-break systems or from different power sources.

If the problem persist after grounding then you must consider using ferrite donuts at the end of the cables, previous to the connectors/plugs. The ferrite donuts will decrease considerably your interference/static and even RF.

Sources: My current installation at a TV/Radio Station where I work.

You should also consider moving this question to another forum and drop back a link in order to continue the support, if needed.

Good luck.


System Settings won't load after Ubuntu 14.04 installation

Try to run unity-control-center in a terminal, since gnome-control-center is not the default in Ubuntu 14.04 anymore.


How do I list DNS server order in systemd-resolve?

It is stupid, but you can't!

systemd-resolved follows internal rules to choose the "correct" DNS. This might be different for each query. It uses things like if a server worked or failed in the past, interface order and even what domains allocated to each interface. It's difficult to manage with some VPN setups.

The best you can do is check the /run/systemd/resolve/resolv.conf file. That is the resolv.conf file generated by systemd-resolved.


Go to the upper right corner and use the gear menu to select Shut Down.


Should I remove system hdd with windows 7 TrueCrypt encrypton before making it dual boot with Ubuntu?

The TrueCrypt documentation mentions that you can decrypt system partitions and system drives and to do this select System > Permanently Decrypt System Partition/Drive. After having the partition decrypted, resize the HDD manually (with partition manager of your choice) or just allow Ubuntu installation to handle it (install alongside Ubuntu). You may then re-encrypt the windows partition.

These links should help:

Encrypting a Linux/Windows dual-boot system
Boot Linux using Windows 7 boot loader


How to permanently disable touchpad in 12.04?

I installed Pointing Device (package: gpointing-device-settings) from the store and it did disable my touchpad.


Try to re-install Ruby, then Gem and then install Rails. Problem maybe is on Ruby or Gem.


What does it mean to run gedit in standalone mode?

Looking it at the source, -s makes gedit always start a new process and a new window, rather than adding a tab to an existing gedit window that's already running. Useful if you're worried about one window crashing taking down the other. You can do the same thing with gnome-terminal with the "--disable-factory" switch, which is useful, as g-t has been known to crash, and take down the processes running in all your tabs and windows with it!

Edit: And the docs you linked above point out that it's also useful if you're invoking gedit from a batch file, or from a mail program, etc. - "gedit -s" will create a new process that won't exit until the window is closed, whereas plain "gedit" will return immediately if there's already a gedit process running.


Audio icon is missing. how can i get back?

Open unity menu
Go to settings
Select "Sound"

Now check "Show sound volume in the menu bar".


How to use .iso file downloaded inside oracle virtual box?

A couple of ideas:

network shared folder link
connect usb and add it to the vm link
copy with scp
ftp server link
run web server from the folder containing .iso file python -m SimpleHTTPServer

All except for flash drive options can be used on both host and client.


wireless network connection fails after suspending

I found out that sudo modprobe -r rtl8723de did not really unload the driver. This can be checked by lsmod or lsmod | grep 8723de. If the driver is loaded, it is listed in the output, if not, the driver is unloaded.
To unload, I had to use the command rmmod and for some reason to unload the driver I had to call it by 8723de.
So I did:
sudo rmmod 8723de

And then reloaded the driver:
sudo modprobe rtl8723de

The Internet connection started working then.
I automated this adapting the accepted solution from this site:

Ubuntu 18.04 - Ethernet disconnected after suspend

Type sudo nano /lib/systemd/system-sleep/rtl8723de-refresh. Insert:
#!/bin/bash

PROGNAME=$(basename "$0")
state=$1
action=$2

function log {
    logger -i -t "$PROGNAME" "$*"
}

log "Running $action $state"

if [[ $state == post ]]; then
    rmmod 8723de \
    && log "Removed rtl8723de" \
    && modprobe rtl8723de \
    && log "Inserted rtl8723de"
fi

Save and exit with Strg+X and C.
Make executable with:
chmod +x /lib/systemd/system-sleep/rtl8723de-refresh

As a remark, I got the driver from this site: https://github.com/smlinux/rtl8723de.git


How to use Audio Recorder to record tracks in separate files?

First of all: the "Add" option beside the name of the output file must not be checked in order to avoid potential new files being added to the previous one. (I guess this is the default setting in fact!!)

As for the settings in the Timer, it is a matter of trial an error, and changes should be made from case to case.

A good start would be adding in any case 'start if sound', so that a new file should be created when sound starts; but in order to have a new file, first the recorder must be made to stop when there is no sound. 'stop if silence' is not a good option, as it creates a lot of small useless files; a better option is 'stop if silence 1 sec.'. 'stop if silence 0.5 sec' may also be a good option. (This should be enough for the stated purpose. Using audio threshold timer commands seems to me more complicated.)

Changing volume level during recording is a bad idea.


By the way, I also need to remove the corresponding model item, but how do I do that?

Apparently this was the solution: I just deleted from the model, and the view updated itself.

I added an ID to the listElements:

ListElement {itemId: 1; itemName: "one"}

In the action's onTriggered, I searched for the item and removed it from the model:

onTriggered: {
    for(var i = 0; i < listModel.count; i++) {
        if(listModel.get(i).itemId === itemId) {
            listModel.remove(i);
            break;
        }
    }
}

Actually, searching is not even necessary. According to the API docs for QtQuick.ListView:

  The index is exposed as an accessible index property.

So it's possible to write just:

onTriggered: {
    listModel.remove(index);
}

So I suppose the object was indestructible because it still had a corresponding item in the model - which makes perfect sense. But in this case... maybe the documentation is a bit misleading.


You could start your command using cron.

Open terminal
Run crontab -e to run command as user1
Add to the end:

* * * * * /bin/date >> /home/user1/mydate

to check if /home/user1/mydate file appears and you could see its content

Create ~/scripts folder: mkdir ~/scripts
Add your command to /home/user1/scripts/bitcoinz script: vim.tiny ~/scripts/bitcoinz (hit i for editing)

#!/bin/sh
/home/user1/bitcoinz/src/bitcoinzd -datadir=/home/user1/bitcoinz/data > /dev/null 2> /dev/null &

Save and exit (For vim.tiny: ESC to exit eiditing mode, then :wq to save and exit)

Make script executable: chmod +x ~/scripts/bitcoinz
Run crontab -e and add to the end:
@reboot /home/user1/scripts/bitcoinz

You could set parameters inside of script. You could also run cron as root user using sudo crontab -e, so it could start as root after reboot.

To make a service as you said in title, do the next:

Create the new systemd service:

sudo vim.tiny /lib/systemd/system/bitcoinz.service
sudo ln -s /lib/systemd/system/bitcoinz.service /etc/systemd/system/

Paste the next to it:

[Unit]
Description=Start bitcoinz
After=suspend.target

[Service]
Type=simple
ExecStart=/home/user1/scripts/bitcoinz
RestartSec=10s
Restart=on-failure

[Install]
WantedBy=multi-user.target

Enable and start the newly created service:

sudo systemctl enable bitcoinz && sudo systemctl start bitcoinz

To work with service as user:

Create the directory mkdir -p ~/.config/systemd/user
Create ubitcoinz.service file there: touch ~/.config/systemd/user/ubitcoinz.service
Edit it and add there entries as in previous file
Use --user option to work with it

systemctl --user daemon-reload
systemctl --user enable ubitcoinz
systemctl --user start ubitcoinz

Output of bitcoinz command could be viewed using journalctl -u ubitcoinz
To start user service not only if user logs in, but at boot:

loginctl enable-linger user1

Check status:  loginctl user-status user1

Reference


Ubuntu 14.04.5 LTS doesn't shut down in a MSI PX60 6QE laptop

Add the command acpi=off to your grub boot. That may or may not work.

As an FYI, this is an acpi error-
the "Will now halt", and then the corresponding freeze, means that your computer has completely shut off the CPU and other components. You can safely shut the power down- holding the power button shouldn't result in power loss.

TL;DR- It's perfectly fine to shut down the computer by holding the power button

Also, consider upgrading to 16.04.


Can I turn off the message at the bottom from mails generated by Ubuntu One-Thunderbird integration?

Well, I have asked to the Thunderbird team. This cannot be turned off easily, but if you have idea to make it looks better, the relevant code is available here: http://mxr.mozilla.org/comm-release/source/mail/components/compose/content/cloudAttachmentLinkManager.js#330 and developers will be open to comments or tweaks about this code.


CPR file is a Cubase Project file which belongs to the Steinberg Cubase music composition software.  Unfortunately you can only open them natively in Windows and MAC OS.  So to be able to open them under Ubuntu, you may look into using Wine.

Or you could try using the Cubase Elements to open your .cpr files and save as Standard MIDI Files .mid, which virtually anything can open.


TLP configuration with addition of second hard drive?

After adding your drive, run:

sudo tlp diskid

You will get a list of devices like this:

  sda: ata-GE224596LL
  sdb: ata-DV00493T11
  sr0: ata-ASUSDVD-RAM_GGLE

Then open the tlp configuration file:

sudo nano /etc/default/tlp

There is a line which you can specify your drives to be managed with tlp, started with DISK_DEVICES, add your preferred devices to that line:

DISK_DEVICES="sda sdb"

In contrast of devices names (sdX), you can do the assignment using IDs:

 DISK_DEVICES="ata-GE224596LL ata-DV00493T11"

Now things like advanced power management, spin down timeout, etc will apply to your chosen drives. in fact this line defines the hard disk parameters are effective for which drives.

You can check that it's working with utilities like hdparm, for example:

sudo hdparm -B /dev/sda

Returns APM Level for sda.

the only config specially for Ultrabay is:  BAY_POWEROFF_ON_BAT, more info.


Prompt to allow ssh connection on server

If your friend trust you, but would like to control when you'll login his computer, I can suggest the following:

Provide your friend a simple explanation how to start / stop the openssh server
Add a unique user for you, which he will allow access (by changing shell or by changing the password to a known pre-defined password)

Using one of the above two simple method will allow your friend to enable/disable the ability login into his laptop by himself.

The trigger to enable/disable access might be a phone call / SMS / etc.


Booting Ubuntu from USB while running Ubuntu

Are you sure that your live disk is working correctly?

If you're able to boot to Ubuntu on your HDD then it sounds like the issue resides with your USB.

https://www.ubuntu.com/download/desktop/create-a-usb-stick-on-ubuntu

This might be of some help.

Just something to check is, does it show up in the BIOS as a bootable disk? It could be that Grub doesn't realize it's there but your BIOS recognizes it as a viable option.

I've had issues with thumb drive live sticks, for whatever reason they don't seem to be as stable as a DVD running the OS. If you're able to create a Live DVD I would try that as well.


Black display after wake from suspend via closing the lid

i changed my video driver to solve this problem.

System Settings-> Software & Updates -> Additional Drivers.

I was using the X.Org X server Video driver for "AMD/ATI display".
I switched to the AMD graphics accelrators from fglrx-updates.

my video card is Radeon HD 6480G(Asus laptop)


I think I've seen something like 'elan touchpad' in the 'scan keys' setting of OnBoard. Is that what you are looking for?


How to emulate a remote host shell environment on my ubuntu 16.04 LTS workstation

First of all, you should read about POSIX and different shell implentations. Then, if you need portability, try to write your scripts as POSIX-compliant as possible.

For testing your scripts to work with busybox, you can install and run the busybox default shell ash to check your scripts syntax to work with busybox:

sudo apt install ash
ash
# non-posix function declaration (works in bash, but not in ash)
$ function test(){ echo Hello World; }
ash: 1: Syntax error: "(" unexpected
# posix-compliant function declaration (works in ash and bash)
$ test(){ echo Hello World; }
$ test
Hello World

But that might not be enough, as this will still use the GNU version of the default tools and has all your other installed programs, which are probably not installed with your busybox.

ash
$ grep --version
grep (GNU grep) 2.25

If you have docker, you can run a busybox container with just its default tools:

docker run -it --rm busybox
$ grep --version
grep: unrecognized option `--version'
BusyBox v1.29.3 (2018-10-01 22:37:18 UTC) multi-call binary.


cannot allocate free space, format extended partition

Among those partitions created by you , find which one is logical partition and delete that partition.

PS: use Gparted instead of using Disk utility. Gparted is more featured than disk utility.

sudo apt-get install gparted


Problem was with grub settings. Using GRUB Customizer I set it to load the latest kernel and everything is running as should. And of course it was possible to check updates via apt commands but problem was the error in software update occurred in the GUI and the afterwards checking in the command prompt showed no traces - a catch 22!


Proxy failing because system resolves it using local DNS instead of VPN (Ubuntu 20.04)

Try to swap the order of search <local_dom> <vpn_dom> to search <vpn_dom> <local_dom> in your resolv.conf file.


Check for firewalld and ufw if are installed could blocking required ports listed here: https://userbase.kde.org/KDEConnect