The /dev/mapper/{whatever} entries you describe are not partitions; they're logical volumes in a Linux Logical Volume Manager (LVM) configuration. Logical volumes are contained by one or more physical volumes, which are partitions. This extra level of indirection buys flexibility -- but the details of that would be a significant detour from an answer to your question.

If you use the "Something Else" installation option and plan to re-use your existing LVM configuration, you must explicitly assign at least two or three partitions or volumes, and possibly some others:

/boot -- If you use LVM, /boot must be a partition and outside of the LVM. This is true of Ubuntu, CentOS, or any other Linux. Thus, there's probably already a /boot partition, with a device filename such as /dev/sda1, /dev/sda2, or something similar. This partition is normally pretty small -- typically in the 500MiB range.
root (/) -- You must assign one partition or logical volume as your root (/) filesystem -- that is, its "mount point" is /. People who are unfamiliar with Linux partitioning often neglect to set a device as root (/) and then don't understand why the installation won't proceed. In an LVM configuration, this filesystem is usually a logical volume. Note also that root (/) is the base of the filesystem tree; it is not the same as /root, which is the superuser's home directory. The root (/) filesystem can be as small as a few gibibytes or as big as the whole disk, depending on your needs and preferences.
swap -- Swap space is not strictly required, but most installations assign a partition or logical volume of one to two times the available RAM as swap space. In an LVM configuration, swap space is usually implemented as a logical volume.

Your CentOS installation probably has a /boot partition and at least the two logical volumes I've just described. It may have other logical volumes for /home, /var, and other purposes. If you want to re-use these existing partitions and logical volumes, you may, but it's up to you to figure out what partitions and logical volumes to use for what purposes. The old functions should be pretty obvious, unless there are numerous logical volumes.

As to the installer entering an endless loop if you try to use the option to overwrite existing partitions, that definitely sounds like a bug. I recommend you file a bug report. Bugs will only be fixed if developers know about them, and it's unlikely that the right developer will stumble upon your post here.

If you don't want to use an LVM configuration (Ubuntu doesn't use LVM by default), you should be able to work around the bug you've found by using any partitioning tool to delete the existing partitions, then re-run the Ubuntu installer. If you do this, you don't need to worry about the LVM setup's logical volumes; when you delete the containing physical volume partition, the logical volumes will disappear. You should reboot after deleting a physical volume, though, to be sure the kernel isn't still trying to use the logical volumes.


The first function checks whether file $CHAGE_SCRIPT exists, and if not attempts to create it with a printf statement. You can see what this statement does by running it in a terminal:

$ printf "#%c/bin/bash \nfor i in \$(awk -F: '{if(($3 >= 1000)&&($3 <65534)) print \$1}' /etc/passwd); do \nchage -m 0 -M 60 -W 10 \$i \ndone \n" !
#!/bin/bash
for i in $(awk -F: '{if(( >= 1000)&&( <65534)) print $1}' /etc/passwd); do
chage -m 0 -M 60 -W 10 $i
done

You will notice that instances of $3 evaluate empty because (unlike \$1) they are not protected from expansion by the shell. The use of %c to insert the ! in #!/bin/bash suggests the original author doesn't really understand how bash's history expansion works.

IMHO it would be simpler and clearer to use a here-document:

function bacon.config.ubuntu.chage() {
CHAGE_SCRIPT='/etc/cron.daily/userchage'
if [ ! -e "$CHAGE_SCRIPT" ]; then
    cat << 'EOF' > "$CHAGE_SCRIPT"
#!/bin/bash
for i in $(awk -F: '{if(($3 >= 1000)&&($3 <65534)) print $1}' /etc/passwd); do
chage -m 0 -M 60 -W 10 $i
done
EOF
    chmod +x "$CHAGE_SCRIPT"
fi
}

The operation of the second function should be pretty obvious - it could be simplified by combining all the sed commands so that the file is only written / moved once.


The problem was I was on Ubuntu 64-bit, so I switched to Ubuntu 32-bit and everything works fine now.


Ubuntu 18.04 login loop problem with gnome; unity works fine

Had a similar issue. Try the following from the working Unity environment

Using the Ubuntu Software Application install GNOME Tweaks
GNOME Tweaks has a menu item named Startup Applications
Remove all or only the application that is likely to be causing an issue. In my case the application was System Load Indicator
Logout of the Unity environment and try to login to the default Ubuntu environment.


Application keyboard shortcuts can't modify in gnome

This configuration item has been moved to the gsettings system.  You should be able to set the new configuration value with:

gsettings set org.gnome.desktop.interface can-change-accels true

If you prefer a graphical tool to modify these settings, try installing the dconf-tools package to get the dconf-editor tool.


Two more programs to watch for: Update Manager (update-manager) and Ubuntu Software Center (software-center).


Try installing bumblebee

Post that, start the bumblebee server.

Launch the application using optirun

"optirun wine app.exe"

Worked for me. Hope it helps.


I want to install oracle-java8 on Linux but Ubuntu says: already the newest version

You can select the system wide java default executable via update-alternatives. Run the update-alternatives command with --list option to see the currently installed alternatives:

$ update-alternatives --list java
/usr/lib/jvm/java-11-openjdk-amd64/bin/java
...

Than change the default to your required java version with:

$ sudo update-alternatives --config java

and follow the instruction on the screen.


It is sorted. Sorta big adventure, but I did it.
Based on this: How do I fix a "Wireless is disabled by hardware switch" error?
And we need WICD for that. The manual to install WICD on Ubuntu 20.04 I found over here: How to install WICD on ubuntu 20.04?
So step by step:
Installing WICD (maybe available somewhere else, but I used this way via terminal):
mkdir -p ~/Downloads/wicd
cd ~/Downloads/wicd

wget http://old-releases.ubuntu.com/ubuntu/pool/universe/p/pygtk/python-gtk2_2.24.0-6_amd64.deb
wget http://old-releases.ubuntu.com/ubuntu/pool/universe/p/pygtk/python-glade2_2.24.0-6_amd64.deb

wget http://old-releases.ubuntu.com/ubuntu/pool/universe/w/wicd/python-wicd_1.7.4+tb2-6_all.deb
wget http://old-releases.ubuntu.com/ubuntu/pool/universe/w/wicd/wicd-daemon_1.7.4+tb2-6_all.deb
wget http://old-releases.ubuntu.com/ubuntu/pool/universe/w/wicd/wicd-gtk_1.7.4+tb2-6_all.deb

sudo apt-get update
sudo apt-get install ./*.deb
sudo apt-get install ./*.deb # second time for correct configuration

And then I uninstalled default network manager since it's not working and just messing around. And WICD does the job just fine.
sudo apt-get remove --purge network-manager-gnome network-manager
Once again: my issue was that the hardware switch (WIRELESS ON/OFF) is broken (always OFF) and was disabling my USB WiFi Adapter. And to bypass this I have to use WICD.


When copying files via USB from Ubuntu to Windows 7, there is a different number of files

The trick is . . . hidden dot files( the ones that have leading dot in the name, e.g. .file1.txt ). They are included in the total count of files and folder size , but are not shown by default. Observe the example bellow: I've a folder /home/xieerqi/EXAMPLE where I copied contents of my /etc/passwd file. In the properties you can see total count of two, but without .test1 being shown , you will only see test2.

What you want to do is open file manager's  View menu and ensure Show Hidden Files is checked, or press Ctrl+H to have the same effect. Alternatively , if you are not shy of using command line, you can use rsync -a SOURCE_DIR DESTINATION_DIR

 rsync -a /home/user/Pictures /media/user/usb_drive


I finally discovered that Ubuntu is missing bluetooth drivers.
Folow these steps:

Download driver.
Install the package.

sudo gdebi ~/Downloads/broadcom-bt-firmware-10.1.0.1115.deb

or
sudo dpkg -i ~/Downloads/broadcom-bt-firmware-10.1.0.1115.deb

Note: Make sure to use the correct path.

Reboot.


How to run the C# program in ubuntu 14.04 using VS code?

install .NET Core, and try dotnet run: https://www.microsoft.com/net/core#ubuntu


list of available targets for openUrlExternally

So doing some digging around on the phone I found the answer. "message" is the magic word.
You can find the system url dispatchers in the folder /usr/share/url-dispatcher/urls

and 3rd party applications store them

/opt/click.ubuntu.com//name.url-dispatcher

on Ubuntu proper it can be found in

/usr/share/applications

among other places I'm sure.


How can I make a bootable USB drive to replace Windows?

If you want to create a bootable Ubuntu USB stick from within Windows please follow the instructions :
How to create a bootable USB stick on Windows.

Also you can use Unetbootin instead of Universal USB installer.

See the general page of Unetbootin here : Unetbootin


Ubuntu 12.10 shutdown/restart from login-screen

There is an issue for some users in 12.04 and 12.10 where shutdown/restart only logs them out of their user session and does not shut down the machine, and using shutdown/restart from the login screen does nothing. It is apparently just a bug. You can try some of the solutions you may be able to find in Google but nothing has worked reliably for me.

You can still shutdown your computer by opening a tty terminal (CTRL-ALT-F2 through F6), logging in as root, and entering

shutdown -h now

which will shutdown the system or

reboot

which will reboot it.


You can use this:

sed 's/$/ ***/' filename

If you want to search for a specific string before appending to a line (that is you don't want it appended to EVERY line like the above command) you can use the following, this finds Fred Flintstone anywhere in a line, put^ in front if you only want to match the beginning of the line.

sed '/Fred Flintstone/ s/$/ ***/' filename


There is a package called mousetweaks that provides tools for manipulating the mouse setting. This is from the proposal:

Delay-click
Click and hold the left mouse button to simulate clicking the right mouse button. Holding the left button for n seconds without moving the cursor more than x pixels initiates a right click+hold. Releasing the left button also releases the simulated right hold. Useful in using the context menu with only one mouse button.
A configuration panel should present the following settings: Enable, time delay.

This from the launchpad page:

The main application provides dwell-clicking which simulates different mouse clicks without using physical buttons and a delay-click feature which opens context menus by holding the left mouse button for a specified amount of time.

If this does not provide what you need (it is from 2007...) you could file a feature request.


Nautilus reports a different amount of space than fdisk does

The answer is actually is in your question itself, you wrote

  [...]fdisk [...] did detect the real amount of storage, which is 14.9 GiB , but nautilus is detecting 16 GB [...]

Nautilus uses the metric prefixes  (1000 bytes = 1 kilobyte (KB), 1000 kilobytes = 1 megabyte (MB) etc.) whereas fdisk uses binary prefixes  (1024 bytes = 1 kibibyte (KiB), 1024 kibibytes = 1 mebibyte (MiB) etc.).
14.9 GiB = 14.9×1.024³ GB ≈ 15.99875 GB ≈ 16 GB, so it adds up.


How can I check how many Python versions are installed?

There's a command called whereis which does that for you :

 whereis python


Can not use Swap file on ZFS: Files with holes

I think what you want is actually well documented on the ZFSOnlinux page

TLDR;

# To set swap on a zfs drive:
zfs create -V 8G -b $(getconf PAGESIZE) -o logbias=throughput -o sync=always -o primarycache=metadata -o com.sun:auto-snapshot=false VMs/swap

mkswap -f /dev/zvol/VMs/swap
swapon /dev/zvol/VMs/swap

# IN FSTAB
/dev/zvol/VMs/swap none swap discard 0 0


Gedit has Snippets plugin:

Go to Preferences from window menu, Plugins, check Snippets.
Select Manage Snippets from window menu and set-up C++.

Test with new test.cpp file, enter main and click Tab, it will expand to standard main function:

int main (int argc, char const* argv[])
{

    return 0;
}

If it is not enough - you may want to try Geany.


noobslab/themes repository for Ubuntu 16.10

ppa:noobslab/themes does not have any packages in it for Ubuntu 16.10. The latest published packages in ppa:noobslab/themes are for Ubuntu 16.04.


blank transparent window on startup unity 15.04

I think that running xprop and selecting this blank window will help you to know which process creates it.


How to permanently disable the num lock key in Ubuntu 14.04

To add context to SetJmp's answer in case you don't want to read through UbuntuForums:

Run xev in a terminal
Press the key that you want to disable (in this case, num lock).  Note the keycode (in my case, 77)
Run xmodmap -e 'keycode number = NoSymbol'.  In my case, this was xmodmap -e 'keycode 77 = NoSymbol'

I haven't tested if the keycode is standard across computers or if additional steps are needed to make it persist across reboots.


Try Issuing the Following Commands in a Terminal:

sudo modprobe -r iwlwifi

and

sudo modprobe iwlwifi 11n_disable=1

The First Command Will Turn Off the Wireless Service.
Thee Second will Restart it with the N Wireless Disabled

This is because there is a bug in Intel Wireless Cards that Makes it preform very slow when connected to wireless N Networks


First find out how the monitor is identified.

cat ~/.config/monitors.xml

That command will print out your monitor's current settings. Find the active display such as HDMI1 for me. Once your have your display figured out, you can change the settings with xrandr.

xrandr --output HDMI1 --mode 1920x1080

That will force my monitor connected to HDMI to be in 1080p.

If you really want to make this with GUI, you could edit monitors.xml with gedit.

gedit ~/.config/monitors.xml

In there you can change the height and width, then reboot.


This site is about Ubuntu, not Linux Mint.

If you want to install the Cinnamon Desktop on Ubuntu, follow the instructions in How do I install the Cinnamon Desktop?.


In Shotwell 0.15.1:  Start a slideshow using View -> slideshow.

During the slideshow at the bottom of each photo there is a little tab
showing stuff:  leftarrow, stop, rightarrow, settings, back to thumbnails.

Click on settings and have a field day.


Installing Xampp on Ubuntu 16.04 gives error command not found

Make sure to change directory to Downloads:

cd Downloads/

You need to make the file executable :

sudo chmod +x xampp-linux-x64-5.6.30-1-installer.run

Then run the file:

sudo ./xampp-linux-x64-5.6.30-1-installer.run


Converting 10.10 desktop iso to alternate iso

I do not know what you mean by "convert". You may want to use zsync to download alternative cd using desctop cd as a base:

zsync -i maverick-desktop-i386.iso http://cdimage.ubuntu.com/daily/current/maverick-alternate-i386.iso.zsync

In that case zsync will download only those parts of alternate cd that are different from desktop one.


Problem booting Kubuntu TPM_error, issue with Nvidia drivers? NVS 5400

For me this sounds like that you have some element in your boot chain that tries to evaluate the system integrity during the boot process. PCRs hold SHA1-fingerprints of stuff executed during the boot process like the BIOS. When the code tries to read the PCR value, things go south.

Have a look into your BIOS/EFI. Go to the security tab. Here you should find settings related to "security chip" (which is the TPM).

I take the TPM is off. Try to enable it. Also try to enable the "security reporting" features of the TPM.

Reboot.


The package python3.2 needs to be reinstalled, but I can't find an archive for it

You can use 'Synaptic Package Manager' to reinstall python3.2

Download synaptic with terminal:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install synaptic

Once installed, open synaptic (you need to type in your password) and mark the following dependencies (see screenshot) for installation, then hit the apply button:

Another option is to simply download it directly, using terminal:

sudo apt-get install python3.2

Like in the screenshot you are prompted for Y/N option. Hit Y then enter button.


nautilus exiting with segmentation fault after upgrade

Remove the nautilus-open-terminal extension. This is causing problems right now and there is an open bug about it (see here).

This bug is now marked as fixed. If you are still experiencing the problem you may have another problem.


Faststone Image Resizer equivalent for Ubuntu

You can try XnViewMP, it works for my needs.


./autogen not working on Ubuntu to install watchman for react-native

Had similar problem and turns out that I was missing some binaries and that needed to run the watchman scripts as root. Here is a shorts script that I used to get everything working:

# install watchman
sudo apt install -y libssl-dev autoconf automake libtool build-essential python-dev
cd $HOME
git clone https://github.com/facebook/watchman.git
cd watchman
git checkout v4.9.0  # the latest stable release
sudo ./autogen.sh
sudo ./configure
sudo make
sudo make install

# linux specific watchman configs
watchman --version
# increasing the watcher limits (need to do every time machine starts up)
echo 999999 | sudo tee -a /proc/sys/fs/inotify/max_user_watches && \
echo 999999 | sudo tee -a  /proc/sys/fs/inotify/max_queued_events && \
echo 999999 | sudo tee  -a /proc/sys/fs/inotify/max_user_instances && \
# restart server
watchman shutdown-server


The command

optirun nvidia-smi

will print out the temperature and some other informations too.

UPDATE: The below comments suggest that in some unofficial packages of the nvidia-driver the nvidia-smi binary is not properly linked to /usr/bin/. If you have such problem that the nvidia-smi command is not found then look at /usr/lib/nvidia-XXX/bin/nvidia-smi for the binary, where XXX is your driver version number. (Or just do a do a locate nvidia-smi or a find / -name nvidia-smi to search for the file.) If you found the file just link it to /usr/bin/ to be available as a simple command, so do something like this:

sudo ln -s /usr/lib/nvidia-331/bin/nvidia-smi /usr/bin/nvidia-smi


I recently did a switch from Windows to Ubuntu, and I installed my Ubuntu on SSD. I was worried to lose my data on Hdd so I backed up all my data of HDD. Now after I performed a clean install, it gave me option to select on which disk to install Ubuntu on. So on this step you need to select your SSD and you will be good to go.
After the clean install on SSD, my data on HDD was completely as it is and after the first boot the HDD was auto-mounted in my Ubuntu. Remember your SSD will be formatted during this clean install.
TLDR: Select your SSD after choosing the clean install option on Ubuntu installer.


Mobile broadband modem on acer aspire one not working

I've seen this problem with numerous operating systems. the driver isn't re-initialized when coming out of suspend and has to manually be disabled and re-enabled to properly start. The easiest way I know of to accomplish this (regardless of operating system) is to reboot or shutdown and restart.

Another thing you could try would be to stop and restart the networking service

Edit:

Another approach which may work for you is tag the driver for unload on suspend and reload on resume.

1) First we need to identify the driver in use. We can do this with the command sudo lshw -C network | grep driver (copy the driver name that comes after the driver= from the output of the command)

2) Next we need to write a configuration file with the command
sudo gedit /etc/pm/config.d/config

sudo gedit /etc/pm/config.d/config

Add a line that says SUSPEND_MODULES="driver name" where driver name is the value that you copied above. This does not always work but might in your case.

service

Additional Sources:

How can I check the information of currently installed WiFi drivers?

https://ubuntuforums.org/showthread.php?t=2004690


I'm using 10.10 on AMD64 platform and the video is working fine without having installed ubuntu-restricted-extras.

I've reopened the page a few times and i've experienced the problem you're facing.

"Configuring playback" seems to stuck there sometimes, but as soon as the timebar is loaded (total time 1:52:07), if i scroll to the right a few seconds or minutes, the video starts playing correctly.


Cockpit Software Updates - Loading available updates failed - Cannot refresh cache whilst offline

According to this, the easiest workaround until Ubuntu settles on a network manager is this:
nmcli con add type dummy con-name fake ifname fake0 ip4 1.2.3.4/24 gw4 1.2.3.1


Can I package and include in the ppa the required libraries?

If the libraries are in the standard Ubuntu libraries then you don't need to include them in your package, they just need to be in the "Depends" field in your debian/control file.

If the libraries are not in the standard libraries, you can include them in a couple of ways:

Include them in the binary package of your application, so that they will install to the same place as your application code.
Include them in the source package of your application, but have them build into a separate binary package.  The separate binary package will need to follow the same rules about installing to /opt/ though, so your application will need to know to look for it there.


The file that stores information about what DNS servers to consult when resolving domain names is /etc/resolv.conf. But the problem with this file is that it is strongly advised not to edit that file by hand because if you do, it's soon going to be automatically overwritten by the resolvconf program. What you can do, however, is add the following lines to the /etc/resolvconf/resolv.conf.d/head file:

# Google's public DNS servers
nameserver 8.8.8.8    # Primary DNS server
nameserver 8.8.4.4    # Secondary DNS server

This file is used when constructing /etc/resolv.conf. Specifically, its contents are added to the beginning of the /etc/resolv.conf file.


PHP 7 is not available in the Ubuntu 12.04 (Precise) official repositories, but you may be able to add it from a PPA following a guide like this one from DigitalOcean (though the DO one is for 14.04, so you'll have to adapt it a bit).

Notice that the Ubuntu Developers maintained PPA for PHP 7.0 is only available for Xenial and Yakkety.


Rails is not available for Ruby 1.9.1 - so if you remove Ruby 1.9.1, you can choose: either you use RVM to install Ruby 1.9.2 or you install Ruby 1.8 and you should be able to install Rails (however, using a older version of Ruby == older version of Rails afaik) :)

(I'm using RVM, which I like as it gives me the opportunity to switch between different installations of Ruby and also develop without having to be root - however I would read more about how RVM works before using it on a production server)


Why do these errors appear while running fake run-fake-gps.sh?

If you use the command while you run python follow_me.py:

sudo netstat -ntlp | grep LISTEN

How can I see what ports are open on my machine?

Then you should see your python follow_me.py is using port 2947.
You can solve this by using another port in one of both scripts.


ethernet stopped working on ubuntu 14.04, still works on windows

the problem is solved (mostly):

http://ubuntuforums.org/showthread.php?t=2244401&p=13122787#post13122787


Take the official Ubuntu 13.04 iso here, and install VLC in the software center. It will work just fine...


Automatic installation of NVIDIA CUDA and NVIDIA drivers

Your results of running the command lspci -nn | grep VGA are:

00:02.0 VGA compatible controller [0300]: Intel Corporation Atom Processor D4xx/D5xx/N4xx/N5xx Integrated Graphics Controller [8086:a011] (rev 02)

Your OS has not detected an NVIDIA card installed on it, as you said in your question, and so you should uncheck the NVIDIA driver (331.113) from your upgrade checklist, because you don't need it. If you have already installed nvidia-331, you can also safely uninstall it.

If you have installed either libcudart5.5 or nvidia-cuda-toolkit, you can also safely uninstall them.


No internet connection since upgrading from LTS 18.04 to LTS 20.04

Upgrading from one release to another rarely works well, I would recommend you do a fresh install and of course before doing that backup your files


Poor performance in Ubuntu 13.10 with Intel i5 4670K (intel hd 4600)

Ubuntu and Kubuntu are a bit overkill for a low powered computer.
Try Lubuntu or Xubuntu.

If you still want to use Ubuntu, try disabling it's effects using CCSM.

First install CCSM by typing in the terminal

sudo apt-get install ccsm

Launch ccsm

ccsm

Deselect all effects

Here you can deselect all three options from the effects section.
close and save.

  Use of CCSM can break your system,use it at your own risk.(though changes I have told are safe).


unable to install mediaelch on Ubuntu 14.04

The closest match to the missing libqt5core5 package in Ubuntu 14.04 is libqt5core5a (Qt 5 core module). The libqt5core5 package in Ubuntu 13.10 has the identical package description: Qt 5 core module. libqt5core5 and libqt5core5a are approximately the same size and they also have the same dependencies. The names of the installed files for libqt5core5 are the same (except for version numbers) as their counterpart matching installed files in libqt5core5a. So open the terminal and type:

sudo apt-get install libqt5core5a
sudo apt-get install mediaelch


How to give root privileges to other user

Do this to give sudo access to the given username:

sudo usermod -aG sudo username


Where is the Unity Dash officially defined?

Found a description for developers at http://developer.ubuntu.com/resources/technologies/lenses-and-scopes/, but I was expecting that some sort of "Introducing Unity Dash" page existed somewhere.


How to run script automatically on each login to Unity (Ubuntu 12.04)?

Save your command in a file named .xprofile in your home directory.


Ubuntu is not something you just install on your existing smartphone. It is at a point right now where Canonical is trying to get smartphone manufacturers to ship their phones with it.

They have a page where you can sign up to receive a notification when it is available.

http://www.ubuntu.com/phone/register


How can I fix a corrupted Ambiance theme?

sudo apt-get install --reinstall light-themes

Should do the trick.


boot ubuntu 18.04 from external hard drive on a computer with windows 10

You want a portable Ubuntu system, that can boot both in UEFI mode and BIOS mode.

The easiest solution is to create a persistent live drive

very portable between computers (unless a computer needs a proprietary driver (for wifi or graphics)
easy to create with the tool mkusb:

https://help.ubuntu.com/community/mkusb
https://help.ubuntu.com/community/mkusb/persistent

limits:

You can install and update/upgrade most program packages
You can not make new kernels and kernel drivers (for wifi or graphics) work

It is possible but more difficult to create a portable installed system

portable between computers; you may or may not have problems if you install a proprietary driver (for wifi or graphics)
method to create a portable installed system, bootable both in UEFI and BIOS:

How to make an USB Ubuntu installation more compatible with different computers?
more details at

https://help.ubuntu.com/community/Installation/UEFI-and-BIOS; method up to date, linked image files getting old
How do I install Ubuntu to a USB key? (without using Startup Disk Creator); more necessary to boot in both UEFI and BIOS mode

limits:

You can install and update/upgrade all program packages including new kernels and kernel drivers (for wifi or graphics)
There may be portability problems
When booted , major updates of Windows may damage the boot structure of the portable USB drive with an installed system, so it is a good idea to disconnect the drive, when you intend to boot into Windows.


Netflix requires Microsoft Silverlight plugin with DRM (Digital Rights Management). Even thought there is a native Linux program similar to Silverlight is Moonlight, Moonlight does support DRM so it does not help.

You will have to add PPA (Personal Packages Archives) in order to install Netflix on Linux.

$ sudo apt-add-repository ppa:ehoover/compholio

To install Netflix Desktop on Ubuntu and Linux Mint

$ sudo apt-get update && sudo apt-get install netflix-desktop

Source: How to install Netflix on Ubuntu, Linux Mint and Fedora


Reinstall ubuntu from factory enabling whole disk encription

The short answer to your question is no, you can't encrypt the entire disk after Ubuntu has been installed.

There ARE ways to do what you want....  for example encrypting it using Trucrypt, but the easiest and cleanest way to go is to just do a clean install.

You could look at the following thread but after reading it you may agree that doing a clean re-install is the best way to accomplish what you want.  Enable disk encryption after installation


Ubuntu VMs with static ip address in VirtualBox

First of all you need to understand the type of interfaces and their usage:

1) Host Only: Host only allows you to communicate with host computer only. So you can't use internet or communicate with other VMs.

2) NAT: NAT allows you to communicate with other VMs as well as you can use internet. But you can't access e.g. server running on this VM from other PC on the network.

3) Bridge: Apart from functionality provided by NAT, using Bridge you can access e.g. server running on this VM from other PC on the network.

Hope this helps. Try to test using different interfaces & it'll become more clear.


How to Configure Media Player Connectivity [Java App for Firefox]

MediaPlayerConnectivity is a Firefox extension, so you need to update it through Firefox extension manager or get the latest version at https://addons.mozilla.org/en-US/firefox/addon/446/

Then you need to configure it to open flash content with an external player. However, I never had much success playing flash using it.

If you are looking for a solution to play Flash without the flash plugin on YouTube, then there are better alternatives. See the "Flash Replacement" section of http://firefox-tutorials.blogspot.com/2010/05/flash-optimization.html

I would recommend Minitube or my extension FlashVideoReplacer (doesn't play well if you have MediaPlayerConnectivity enabled).


efi boot order changes on package upgrade

You're running into what I call a "boot coup." I've written a page on this subject; see here for details. That said, your problem sounds a bit unusual, but it is likely related to this:

efibootmgr
No BootOrder is set; firmware will attempt recovery

Ordinarily, an EFI-based computer does have a BootOrder variable set. The cases I personally have seen where it's not set have been because of a defective firmware that simply refuses to accept this variable. On such computers, the only chance of booting is via a fallback filename (typically EFI/BOOT/bootx64.efi on the ESP, although EFI/Microsoft/Boot/bootmgfw.efi will sometimes work, too). That said, I have heard of cases where the BootOrder variable is empty but can be set. In this case, adding an EFI boot variable, as described here, can fix the problem.

If your computer is just badly defective and needs to boot through a fallback filename, you must copy or move/rename the boot loader to the appropriate name, and possibly support files like configuration files.

Given that you referred to "the ubuntu efi entry" makes me think that you've got boot variables, but the BootOrder variable is getting lost. This is probably a firmware bug, although it could indicate defective NVRAM hardware. Upgrading the firmware might fix the problem, if it's a bug. Check with the manufacturer to see if such an upgrade exists. If that doesn't help, you might copy GRUB to the fallback filename, where it should be called if/when the BootOrder variable is lost again. The ESP is normally mounted at /boot/efi, and normal Linux filesystem commands work on it, so you can do this:

sudo cp -r /boot/efi/EFI/ubuntu /boot/efi/EFI/BOOT
sudo mv /boot/efi/EFI/BOOT/shimx64.efi /boot/efi/EFI/BOOT/bootx64.efi

This copies Shim to the fallback filename. If you're certain that your computer doesn't use Secure Boot, you could rename grubx64.efi, rather than shimx64.efi, to bootx64.efi.


Why purchased music is not synched on U1 on Windows7?

It is not synchronized by default. You need to subscribe the folder in the control panel on the folders tab, for the folder to be synchronized. You will also then have to add that folder to your music player by hand on Windows.

They will be located in your home directory (profile folder), under the .ubuntuone/Purchased from Ubuntu One/ sub-directory.


Ubuntu 17.10 laptop doesn't suspend on lid close

Turns out we were all wrong. The magnet which triggers the lid sensor had come away inside the laptop. I confirmed this by holding a fridge magnet up to the camera. As soon as I did that, the laptop suspended fine. So I figured there's a magnet in the base. There was, but it was floating around (clinging to the battery) inside the machine. I put it back in place and it's now working.


Problem black screen with Lubuntu in Virtual Box

(This is just a guess.)

After upgrading to VirtualBox 5.2.6-120293, I started getting the same «black screen».

Disabling «3D acceleration» and «2D video acceleration» (virtual machine «Settings» => «Display» tab => «Screen» sub-tab) has helped.


Use (Windows) BitLocker-encrypted drive on Ubuntu 14.04 LTS

Since Ubuntu 18.04, Dislocker is available in the Ubuntu Universe packages.  It can be installed using
sudo apt install dislocker

You may need to
sudo add-apt-repository universe
sudo apt update

First, we make two folders, /media/bitlocker and /media/mount:
sudo mkdir /media/bitlocker /media/mount

Then, download and then extract Dislocker.
You'll want to install some needed packages:
sudo apt-get install libfuse-dev

To install it, we need to change directory to the dislocker folder:
cd dislocker

Depending on your operating system, you'll need to choose one of
these:

For Debian-like distos based on Debian Jessie or Ubuntu 14.04 or older:
 aptitude install gcc cmake make libfuse-dev libpolarssl-dev ruby-dev

For Debian-like distos based on Debian Stretch or Ubuntu 16.04 or later:
 aptitude install gcc cmake make libfuse-dev libmbedtls-dev ruby-dev

Now we finally install dislocker:
cmake .
make
sudo make install

Here, we need to find our partition so we dont erase all of our drives accidentally:
sudo fdisk -l

If we have a recovery password, we can decrypt it using this:
sudo dislocker -r -V /dev/sdaX -p1536987-000000-000000-000000-000000-000000-000000-000000 -- /media/bitlocker

PS: You should replace 1536987-000000-000000-000000-000000-000000-000000-000000 with your recovery password.
If you know your password, we can just use that too:
sudo dislocker -r -V /dev/sdaX -uPASSWORD -- /media/bitlocker

Pssst: Replace PASSWORD with your User password. Attention: keep the u before the password! So, if your password is UbuntuLover, you shall use uUbuntuLover after the hyphen.
If your disk is mounted to sdb, use option sdb1.
If you are decrypting with a recovery file then use "path/to/.BEK" instead:
sudo dislocker-fuse -V /dev/sdcX -f /media/user/usb-drive/00000000-0X0X-0XX0-XXX0-XXXX0XXX00XX.BEK -- /media/bitlocker

Now, we finally mount our file:
sudo -i
cd /media/bitlocker
mount -r -o loop dislocker-file /media/mount

(If the mount above fails with "Permission denied" add the -r option and try again.)
Now you can move to the /media/mount folder and see your decrypted data.
Read the source for more information and details.


What is the equivalent program to anonytun on Linux?

Anonytun is a service that probably uses an HTTP CONNECT proxy on the server side to implement most of its functionality. So asking what the equivalent is on Linux is somewhat ambiguous. In any case you will still need a VPN server to connect to.

Tools you could use to make a tunnel are xl2tpd, openssh, apache using HTTP CONNECT over TLS, openvpn, openconnect/anyconnect etc.

On Ubuntu installing network-manager-openconnect-gnome would add functionality to the network manager to connect to anyconnect compatible VPNs with similar usability to that app. Furthermore without any special software you can change your proxy settings to use an https CONNECT based proxy (which is partially a tunnel).

"host spoofing" in the context of Anonytun is a somewhat incorrect way of saying that it provides an override to SSL Server Name Indication (SNI). While this information is not encrypted nor is the destination IP address and so a simple reverse lookup would probably reveal the same name meanwhile "spoofing" it will likely result in unexpected things happening. Since it is an SSL proxy this override is likely for the tunnel itself. In the case of anyconnect for example this information just isn't sent at all.


I think your problem is this bug which was marked as a duplicate of this one.

For future reference, similar bugs can be reported by pressing Alt+F2 and then entering ubuntu-bug gcompris. This will allow the developers to help improve gcompris. (The same procedure is used for any application.)


dpkg doesn't function properly after upgrading an AWS EC2 to 14.04

Have you tried reinstalling dpkg?
sudo apt-get install --reinstall dpkg

If this doesn't work, this may be specific to the pythons packages.
Try to modify the postinst file: gksu gedit /var/lib/dpkg/info/python-twisted-names.postinst or another text editor if you prefer.

Delete all the content and replace by

#!/bin/sh
set -e
exit 0

If this still doesn't do it, you can try deleting the status file rm /var/lib/dpkg/status and leave it like that so a new one is built, or replace it with the old one cp /var/lib/dpkg/status-old /var/lib/dpkg/status

I also know these commands dpkg --configure -a and dpkg-reconfigure -phigh -a, they should be useful but I don't know when. Try them at different points. Don't forget to sudo apt-get update at least once before the configure.


Misleading lack of freespace on apt-get install

I think that your inode space is full. sudo tune2fs -l /dev/root

sudo tune2fs -l /dev/root
<snapped>
Inode count:              2445984
Block count:              9764864
Reserved block count:     488268
Free blocks:              6806062
Free inodes:              2265142
<snapped>


I know this is an old post but what worked for me was to "kiss" the mouse scroll wheel and blow as hard as I can. I think that moved/removed some of the dust and lint inside.
Hopefully this helps someone since this is one of the first search results for this issue.


Same command for all files on folder and output on the same file

A for loop converting every .MP4 file in the current directory with Parameter Expansion for the file extension change would look like this:

for i in *.MP4; do
  ffmpeg -i "$i" "${i/%MP4/ass}"
done

${i/%MP4/ass} expands to the currently processed filename with the last occurence of “MP4” replaced by “ass”. Another way of achieving the same is to cut the string from the last dot and add the new extension: ${i%.*}.ass

In a case of multiple, probably lasting operations like this I really like to use GNU parallel, which by running jobs in parallel can highly increase the speed. The above loop with parallel would simply be:

parallel ffmpeg -i {} {.}.ass ::: *.MP4


Possible problems in mixed use of apt-get, aptitude and synaptic

For what I know, different package managers can have different opinions about which packages are installed automatically, or at least it was true time ago, not sure if it is yet so.

This can have consequences on autoremove subcommand (be aware that aptitude does not have an autoremove subcommand, but executes autoremove automatically).

So one can have unuseful packages hanging around, not a big problem anyway.

Also, they can have different opinion about which packages are blocked, but this should not be an issue for the normal user that often make no use of this feature.

The dependencies and conflicts resolution algorithms are more or less equivalent, so in conclusion I think the user can mix the use of different package manager without the fear of breaking something.


This segmentation fault really should not happen. I suspect something is wrong with the binaries installed on your system - possibly because of the symbolic link you created.

Try reinstalling GCC and all affecting libraries:

sudo apt-get install --reinstall gcc gcc-4.6 gcc-4.6-base libgcc1 cpp-4.6

Specifically the cpp-4.6  package appears to be broken in your setup as /usr/lib/gcc/x86_64-linux-gnu/4.6/cc1 belongs to that package and the error output you've provided indicates the cause of the issue is in there somewhere.


Ubuntu 14.04: No sound output! (Well, mostly no sound)

I have same issue with Ubuntu 16.04 and System76 notebook.

Behold solution:

sudo su
echo "options snd-hda-intel model=generic" >> /etc/modprobe.d/alsa-base.conf

Source (not in English)
Find more info here


Error while deploying HTML5 app with Ubuntu SDK

I got this error performing "Publish -> Validate existing Click package" in the Ubuntu SDK.

Performing "Publish -> Create and Validate Click package" solved it for me.


Problem with Copy pasting text from a document on ubuntu

Try to paste it in a no format text editor(leafpad, or what you have installed) and the paste it to google docs. It may delete the "format" that you dont want there.


You can use your Ubuntu desktop PC as a server. It will keep on working, as long as it's powered on of course.

The difference between an server and desktop is the GUI, and most servers in data centers don't have their own keyboard, mouse and screen. Aside from that, you normally don't install LibreOffice or Firefox on a server, and many other libraries and tools.

It's not good practice to install all these applications on a server. Just what you need. A database server doesn't need a webserver, so you don't install Apache, etc. Keep it as simple as possible. This keeps the risk of crashes to a minimum, plus it's more secure, less attack vectors.

For you this is of no importance. Use whatever you need.


Java game - Minecraft - No internet connection

Try running:

    sudo update-ca-certificates -f

if that doesn't work try

    sudo apt purge ca-certificates-java && sudo apt install ca-certificates-java

The problem is caused by the fact that the ca-certificates that come with Ubuntu (and flavors) are a little broken for Java so reinstalling them and reloading them will hopefully fix it.


Installing both lxml 3.1.2 and lxml2 on ubuntu 12.04

Ubuntu makes extensive use of Python in it's distributions. For this reason, my policy is to leave the Ubuntu supplied versions strictly alone and only update them via the update manager or apt-get. In this way I avoid the risk of de-stabilizing some piece of Ubuntu code that is dependent on a particular python package/module version.

I do all my development work in virtualenv workspaces and configure my command line and Eclipse to use the appropriate workspace for whatever application I am working on. Thus I do not interfere with Ubuntu and Ubuntu does not interfere with me.

It is quite likely that a dual installation of lxml will "work" but the installation is likely to be fragile. Why take the risk?


If I understand correctly, you basically want to remove all line breaks that don't occur directly after a ;. If so, you can do:
perl -pe 's/(?<!;)\s*\n/ /' file > newfile

Or, to edit the file in place, use -i:
perl -i.bak -pe 's/(?<!;)\s*\n/ /' file

The above will make the changes to file and create a backup of the original called file.bak. To skip creating the backup just use -i alone, without an extension.
Explanation
The -p means "print every input line after applying the script given by -e. The s/// is the substitution operator. Its general format is s/pattern/replacement/ and will replace pattern with replacement.
In this case, pattern is 0 or more whitespace characters (\s*) followed by a newline (\n) which are not preceded by a ;. The (?<!foo)bar construct is a negative lookbehind, it will match bar if the previous characters are not foo. Therefore, the script above will remove all newlines that aren't just after a ;.


Making a clone of windows drive, then erasing and using Ubuntu

I would recommend shrinking Windows to the smallest comfortable size; say 50 or 60 GB. If you are a gamer then 500 GB or so might be comfortable if you have 1 TB HDD or SSD. After shrinking Windows install Ubuntu in dual boot mode.

You want to keep Windows working for when Ubuntu crashes and you need to use google for repair solutions.
Windows is superior for gaming. Even if you don't use PC games often, sometimes it's nice to sit back and relax around Christmas with a good game.
Windows may have BIOS updates and firmware updates from manufacturers that aren't available in Linux. You apply the updates in Windows and it can fix problems in Linux.
Other people or organizations may send you files that can only be read with a specific Windows application not available on Linux.
You already think you might need Windows in the future which is why you are backing it up. Should you reinstall Windows that means wiping out Ubuntu and having to reinstall it in dual boot anyway.


Converting from Kubuntu to Ubuntu in old install: Fixing the desktop

If the session applet is installed,it may be a matter of simply right clicking the panel and choosing add to panel.
The Applet  you need for your name is "indicate applet session"


Ubuntu 12.04 doesn't know there's a battery

Install dconf Editor via the terminal:

sudo apt-get install dconf-tools

or using the Software Center:

Then perform the action indicated in the screenshot below:


How to install 7zip to extract rar files

I don't know why would you like specifically 7-zip's binary to extract RAR, but here we go:

To unrar files with... unrar:

sudo apt-get install unrar-free
unrar e some.rar

To extract rar files with 7-zip:

sudo apt-get install p7zip-full
7z x some.rar

e and x mean extract obviously.


How do I deploy jenkins and jenkins-slave if they have mismatching series?

The answer is quite simple, yet very unlikely.  The charm for jenkins-slave is a precise charm, which means it can only be installed on a precise Ubuntu VM.

While this only seems obvious after an entire day with juju, I believe it is a major problem with this tool.  Chef / Puppet, etc are not flavor dependent, so why is juju flavor version dependent.  It's a major lack of planning in my opinion.


'mail my_name' command cannot send message

mail needs to be configured in order to receive messages from local users. The easiest way to configure mail is to install sendmail with sudo apt sendmail and the sendmail program will work for 3 to 5 minutes when it is being installed and it will configure mail automatically. sendmail requires additional configuration to send mail via the internet, which I will skip here because your question is about how to use the mail program to send a message to a local user.

Then type mail to start the program and after the ? prompt type the number of a message to read it in the terminal. It can take a few minutes to get a notification that you have received a new message after it is sent. Then you will see that the new message has been added to the list of messages in your inbox.

If you get the error message: cannot send message: Process exited with non-zero status that means that mail did not exit correctly. The way to avoid getting this error message is to make the next line after the end of the body of the message a newline containing only the . character and press Enter. This indicates the end of the message. Then press the keyboard combination Ctrl+C to quit composing the message. Alternatively you can do what it says on page 8 of The Unix Programming Environment and press the keyboard combination Ctrl+D to signal the end of the message by telling the command-line shell that there is no more input.


How to permanently disable key repeating?

Besides setting the repeat delay and speed as you've already done for a workaround, try:

gsettings set org.gnome.desktop.peripherals.keyboard repeat false

Source: Ubuntu 18.04 Repeat Keys wont stay off


How to upgrade my Ubuntu 15.04 to Ubuntu 16.04

Open a terminal window and type in

sudo apt-get update
sudo apt-get upgrade
sudo do-release-upgrade

Enter your admin password when prompted.

Note, the update and upgrade are to ensure your system is up to date before doing the release upgrade.

If the above doesn't work, ensure update-manager-core is installed in terminal with sudo apt-get install update-manager-core.

Using the GUI, launch Software Updater and click on the settings button.

Click on the update tab, it should look like this

Make sure the option on the bottom is selected as seen in the picture (long-term support version).  Apply changes and check for upgrades again.


How do I launch the app from within `quickly test` for gui testing?

This makes me feel dirty, but it seems to be a viable workaround:

class TestMyappClose(unittest.TestCase):
    def test_close(self):
        launchapp('/usr/bin/quickly', ['run'])
        exists = waittillguiexist('*myapp', guiTimeOut=5)
        assert(exists == 1)

        selectmenuitem ('*myapp', 'mnuFile;mnuClose')
        waittillguinotexist('*myapp')


You can use the Network Installer.

The network installer lets you install Ubuntu over the network. This is useful, for example, if you have an old machine with a non-bootable CD-ROM or a computer that can’t run the graphical interface-based installer, either because they don’t meet the minimum requirements for the live CD/DVD or because they require extra configuration before the graphical desktop can be used, or if you want to install Ubuntu on a large number of computers at once.

To download it, see Ubuntu 13.04 (Raring Ringtail) Netboot


Keyboard stopped working after upgrading to Kubuntu 18.04

the software/package Kubuntu 17.10 used for that keyboard, can be deleted during the upgrade.
that can happen in the proces were all deemed´unnessesary´ packages are deleted and replaced by the new/updated ones from the new OS version.

the only tip i can give you, is to look at ´additional drivers´ in 18.04.
there might be software showed for the keyboard.


Disable specific device from waking up the system

Sometimes there are BIOS settings for USB ports to enable/disable power during suspend and/or enable/disable wakeup.
But you may also need to disable wakeup for the relevant USB controllers/hubs. Try this:
cat /proc/acpi/wakeup
I actually don't know how to confirm the device names here is the device you want as the names listed here are different to what you see elsewhere but in my case my USB devices are EHC1, EHC2 and XHC
You can toggle between enabled and disabled by doing for example:
sudo -s
echo XHC > /proc/acpi/wakeup
exit

But I am not sure it's a permanent change. I am not sure on the best way to make it permanent, I just made an executable script to echo the commands I needed and added it to roots crontab like:
@reboot /etc/my_script


Notebook keyboard gets hot only on the left side!

Surface temperature

The question is about an unusual surface temperatue distribution on the body of a very thin notebook. It basically asks "Is that normal?"

Misconfigured?

I took the question as describing side effects of misconfigured fan- or power saving configuration.
I tried pretty hard to find that implied problem, but finally gave up.

Is it normal

A misconfiguration would lead to an answer "No, it's not normal" - but this does not seem to be the problem.

So, let's take it literally - is it normal that the  left side of the case is much warmer than right?

A relevant information is that it's a very thin notebook, the Asus VivoBook S551lb. It is relatively difficult to get heat out of a thin device.
So, let's take a look what is inside on the left side - maybe there's just something related to heat?

In this review of the S551lb there are some images of the opened device.

This image shows of the uncovered bottom side, with keyboard pointing down. We can see a copper heatpipe, ending between fan and air exhaust, and starting from a large heat spreader at the right. The component under that is probably the CPU, but could also be the graphics processor.  But that's irrelevant - what we know it that it's the component that produces the most heat.

Yes, normal!

Now, the solution is easy: turning the device around, the hot component goes to the left;
Is it normal that the case is most hot near the hottest component? Yes.
Looking at the components on the right side, there is mainly a CD drive and the hdd. Both do not get hot, so it's also normal that the right side is relatively cool.

An interesting aspect is that the device has a metal body, probably made of some aluminium alloy - a good heat conductor.
When you touch the surface to tell the temparature, the metal can transport a lot of heat energy from or into your finger in a short time. That makes you feel the temperature much more pronounced compared to the same temperature on a surface of some plastics or wood with much lower heat conduction.

And that is quite relevant to the question: As far as I know, touching aluminium alloy at 60°C would hurt quite badly. So we can now assume that the actual temparature was much lower;
That means that the reason that made me expect a fan/power misconfiguration did not exist in the first place.

See also this review with nice thermal imaging pictures  of the device.


How do I fix a blank desktop after logging into regular Ubuntu (Unity)?

The solution to your "my desktop is blank in Unity (3D)" is simple, but involves using an advanced tool, Compiz Config Settings Manager.

  Warning: Compiz Config Settings Manager is an advanced tool and one tiny mistake, typo or an accidental click of the mouse can leave your desktop unusable, requiring time and effort to fix it. Please be very careful and follow instructions...thanks. Once you are done using it, please consider uninstalling/removing it to reduce future risk. If you mess up, please see this answer on how to fix things.

Install CompizConfig Settings Manager with sudo apt-get install compizconfig-settings-manager in Ubuntu 2D, if you don't already have it.
Logout and log in into Ubuntu (3D)
Right click on the blank desktop, create a new folder.
Click on "File System" on the left sidebar, and navigate to /usr/bin. Scroll down to CCSM and double-click to run it:

Type unity in the Filter box and click on the Unity Plugin:

Just check the "Enable..." box on the bottom left and you should have your normal 3D environment back:


Cannot install packages in my virtualbox machine

It seems is just a stupid mistake I have done, I'have forgot to add DNS server name in my interfaces configurations, so all my packages can't resolves a domaine names.

Solution was :adding the line

dns-nameservers 8.8.8.8

on the file /etc/network/interfaces


Warning: DocumentRoot x does not exist when starting apache2

The recommended way to enable and disable Apache websites is using the a2ensite and a2dissite (short for Apache 2 Enable/Disable Site).

What these two tools do is basically adding/removing links to/from /etc/apache2/sites-enabled. Such links point to /etc/apache2/sites-available.

Because you have removed the files, I'd recommend not just disabling the sites (i.e. removing the links from sites-enabled), but also remove the site configurations all toghether (i.e. removing both the links from sites-enabled and the files from sites-available).

In short, you should:

Find the sites of which you have removed the files: ls /etc/apache2/sites-enabled
Disable such sites: rm /etc/apache2/sites-enabled/site1 /etc/apache2/sites-enabled/site2
(Optional) totally remove the configuration files for such sites: rm /etc/apache2/sites-available/site1 /etc/apache2/sites-available/site2


How to fix erlang unmet dependency errors?

Ubuntu 19.04 has a different code name so I am going to assume that you meant to say you're using Ubuntu 18.04.

Carefully read these instructions. You have to pin the Erlang version and you probably shouldn't mix bintray and packagecloud resources.

The following Vagrantfile successfully installs the latest Erlang and RabbitMQ packages. You should be able to adapt it to your needs.

$script = <<SCRIPT
apt-get install -y sudo
apt-get update -y
apt-get install curl gnupg -y
curl -fsSL https://github.com/rabbitmq/signing-keys/releases/download/2.0/rabbitmq-release-signing-key.asc | sudo apt-key add -
apt-get install apt-transport-https
tee /etc/apt/sources.list.d/bintray.rabbitmq.list <<EOF
deb https://dl.bintray.com/rabbitmq-erlang/debian bionic erlang
deb https://dl.bintray.com/rabbitmq/debian bionic main
EOF
apt-get update -y
apt-get install rabbitmq-server -y --fix-missing
date > /etc/vagrant_provisioned_at
SCRIPT

Vagrant.configure('2') do |config|
  config.vm.box = "ubuntu/bionic64"
  config.vm.hostname = 'UBUNTU-18-2'
  config.vm.provision 'shell', inline: $script
end

NOTE: the RabbitMQ team monitors the rabbitmq-users mailing list and only sometimes answers questions on StackOverflow.


Looks like /sbin is not in $PATH when starting it from cron. Add a line like

PATH = /sbin:$PATH

to the crontab file.


Your command is invalid. gedit-open doesn't exist. The correct command is gedit. Also a slash is missing from the file path.
So, change:

Exec=gedit-open home/user1/Desktop/notes

to:

Exec=gedit /home/user1/Desktop/notes


Try to install it after an update:

sudo apt-get update && sudo apt-get install patch


How to make a second monitor go off after the connected laptop is closed?

If you change the primary display to your Built-In display, it does it automatically. I use a tv as a second monitor and this seemed to work for me. The tv only went blank but did not turn off.


How can I restart the network on 18.04 with netplan?

Add renderer: networkd to the config file:

network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      dhcp4: true


Black screen in installation when Nvidia graphic card plugged

Try to boot a live CD or from an USB and press F6 on the first loading screen of the CD/USB.
Choose 'nomodeset' with your arrow key and try to install the system again.

Otherwise hold the shift-key when booting the installed system and try to edit the Grub entry by selecting "Ubuntu" and pressing e.

If you don't know how to do this use the wiki or let me know.


Can the home partition be created as an extended partition?

Yes - how exactly do you mean though? I'm sort of assuming you mean 'extended partition', in which case it's no different to any other partition in this context - although if you mean 'a separate physical drive' or 'in another room' then it's still yes :).

The normal setup is that you can have 4 primary partitions, and any more have to use one of the 4 as a 'frame' to fit within that limit, hence are termed 'extended partitions'. You can have loads if you really want!


Boot repair did not fix grub rescue prompt, new install ubuntu 12.10

You must reinstall grub and make sure that you install it on correct device (sda , sdb, etc ...). Have a look at this Answer.


How to take a screenshot with the actual pointer icon?

This is the update version of Screenshot application. Here just check the mark on of include pointer.


I solved the problem by doing the following (choose options depending on your hardware):

Run the program "PulseAudio Volume Control"
Select "Output devices - Port: Headphones"
Choose "Configuration - Profile: Analog Stereo Output"


Steam: "failed to load libsteam.so" - ubuntu 12.04

Remove your ~/.steam directory and run steam again.


With your computer you won't notice much difference. 5th generation i5's and a an SSD are a very good combination.

The biggest difference you will see between Xfce and gnome is in the amount of memory usage it takes. So if you are running a machine with only 1GB of ram then you will notice a significant difference.


`0a1` in the output of diff file1 and file2

After line 0 (i.e., beginning) of the first file, a dd the following line (1 st line from the second file).

Note: Since these are ed commands, you should look at the ed man page: http://manpages.ubuntu.com/manpages/disco/en/man1/ed.1plan9.html

Also, google diff command tutorial for more examples.


How to remove requests from python and install in pip

Using sudo -H pip install requests solved the problem:

  Collecting requests   Downloading
  https://files.pythonhosted.org/packages/51/bd/23c926cd341ea6b7dd0b2a00aba99ae0f828be89d72b2190f27c11d4b7fb/requests-2.22.0-py2.py3-none-any.whl
  (57kB)
      100% |████████████████████████████████| 61kB 1.3MB/s Collecting urllib3!=1.25.0,!=1.25.1,<1.26,>=1.21.1 (from requests)   Downloading
  https://files.pythonhosted.org/packages/e6/60/247f23a7121ae632d62811ba7f273d0e58972d75e58a94d329d51550a47d/urllib3-1.25.3-py2.py3-none-any.whl
  (150kB)
      100% |████████████████████████████████| 153kB 2.7MB/s Collecting certifi>=2017.4.17 (from requests)   Downloading
  https://files.pythonhosted.org/packages/69/1b/b853c7a9d4f6a6d00749e94eb6f3a041e342a885b87340b79c1ef73e3a78/certifi-2019.6.16-py2.py3-none-any.whl
  (157kB)
      100% |████████████████████████████████| 163kB 2.4MB/s Collecting chardet<3.1.0,>=3.0.2 (from requests)   Downloading
  https://files.pythonhosted.org/packages/bc/a9/01ffebfb562e4274b6487b4bb1ddec7ca55ec7510b22e4c51f14098443b8/chardet-3.0.4-py2.py3-none-any.whl
  (133kB)
      100% |████████████████████████████████| 143kB 3.0MB/s Requirement already satisfied: idna<2.9,>=2.5 in /usr/lib/python2.7/dist-packages
  (from requests) Installing collected packages: urllib3, certifi,
  chardet, requests Successfully installed certifi-2019.6.16
  chardet-3.0.4 requests-2.22.0 urllib3-1.25.3


Try running this on a terminal:

sudo mkdir /etc/adobe
sudo bash -c "echo 'OverrideGPUValidation = 1' >> /etc/adobe/mms.cfg"

Flash Player has a freeze problem on ubuntu.


Remove postgresql and daemon user entries in Ubuntu Logon Screen

indeed they're essential for certain services but if you just want to hide them, edit /etc/lightdm/users.conf file (the line that says hidden-users =) and append those users which you don't want to be shown.


How to restore the default repositories in 12.04?

I'm dumping my /etc/apt/śources.list. It only contains repositories that come with Ubuntu. Some of them are deactivated in the default configuration but I don't know which ones. Anyway this list shouldn't give you problems. You should also empty the folder /etc/apt/sources.list.d where all ppas you have added are saved.

So here comes the list:

# deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Beta amd64 (20120328)]/ dists/precise/main/binary-i386/

# deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Beta amd64 (20120328)]/ dists/precise/restricted/binary-i386/
# deb cdrom:[Ubuntu 12.04 LTS _Precise Pangolin_ - Beta amd64 (20120328)]/ precise main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu precise main restricted
# deb-src http://de.archive.ubuntu.com/ubuntu/ precise main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu precise-updates main restricted
# deb-src http://de.archive.ubuntu.com/ubuntu/ precise-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu precise universe
# deb-src http://de.archive.ubuntu.com/ubuntu/ precise universe
deb http://archive.ubuntu.com/ubuntu precise-updates universe
# deb-src http://de.archive.ubuntu.com/ubuntu/ precise-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu precise multiverse
# deb-src http://de.archive.ubuntu.com/ubuntu/ precise multiverse
deb http://archive.ubuntu.com/ubuntu precise-updates multiverse
# deb-src http://de.archive.ubuntu.com/ubuntu/ precise-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu precise-backports main restricted universe multiverse
# deb-src http://de.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu precise-security main restricted
# deb-src http://security.ubuntu.com/ubuntu precise-security main restricted
deb http://archive.ubuntu.com/ubuntu precise-security universe
# deb-src http://security.ubuntu.com/ubuntu precise-security universe
deb http://archive.ubuntu.com/ubuntu precise-security multiverse
# deb-src http://security.ubuntu.com/ubuntu precise-security multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu precise partner
# deb-src http://archive.canonical.com/ubuntu precise partner

## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu precise main
# deb-src http://extras.ubuntu.com/ubuntu precise main


What you must do is create a Ubuntu LoCo, or to find one in your city if it has one already. LoCo stands for Local Community team. The LoCo is the one that will organise Ubuntu events in the city, and are officially recognised by Canonical. A LoCo can get support from Canonical, but most of the time support will come from your community.

If you want to join a LoCo Team, it's easy! Just find a team in your area and click the 'Join This Team!' link at the top of their page.

If you are not able to find a LoCo Team in your area and want to create one, take a look at the LoCo Team HowTo for more information on setting up a LoCo Team


Can't start blender on Ubuntu 17.04 zetsy

Solved. All I did was:

sudo nano /etc/ld.so.conf.d/blender.conf

and add below to the this file

/usr/lib/x86_64-linux-gnu/

after I run

sudo ldconfig

Then blender starts normally.

Thanks for your help.


Ubuntu on Macbook: How to restore default boot to Ubuntu?

It sounds like you're suffering from what I call a boot coup. See that page for details, but you can try this:

Boot to Ubuntu. Given your current situation, you may need to use an Ubuntu installation disk in its "try before installing" mode or use my rEFInd boot manager on a USB flash drive or CD-R to boot into your regular Ubuntu on a one-time basis.
In a Terminal window, type sudo efibootmgr -v. This will show your current EFI boot options. My suspicion is that one of these will be called ubuntu, but that the BootOrder will show a macOS entry as being first. (If efibootmgr complains that it can't find EFI boot variables, then you've booted in BIOS/CSM/legacy mode. Try again, but pick a different boot option for Ubuntu.)
At this point there are two possibilities:

If I'm right in my suspicion that you have an existing ubuntu entry, you can set it first by typing sudo efibootmgr -o ####[,####,####,....], where the first #### is the number of the ubuntu entry and subsequent numbers are the remaining entries in the current boot order. Alternatively, you could use the refind-mkdefault script described on my boot coup page, and that comes with rEFInd. You can download it directly here. Type sudo ./refind-mkdefault --label ubuntu to set the Ubuntu entry as first.
If efibootmgr does not show an ubuntu entry, then you need to create a new one. The command to do so is sudo efibootmgr -c -d /dev/sda -p 1 -l \\EFI\\ubuntu\\grubx64.efi -L ubuntu. You can omit -d /dev/sda if that's the hard disk where GRUB is installed and -p 1 if your ESP is partition #1; and if your disk and/or partition are not those values, you must adjust the efibootmgr command appropriately. If you were using a UEFI-based PC, it would be safer to specify shimx64.efi rather than grubx64.efi. On a Mac, either should work; but on the off chance that shimx64.efi isn't installed, grubx64.efi will work and is more direct. As an alternative to this, you could run Boot Repair. This is less intimidating if you're not comfortable with text-mode command-line tools, but Boot Repair is overkill and runs a small risk of making matters worse, so I prefer to stick with efibootmgr as a first attempt.

If neither of these approaches work, it could be that your Ubuntu was installed in BIOS/CSM/legacy mode. In this case, there are several possibilities for how to recover it to boot in that mode again, depending on what's wrong; but it's likely to be easier to recover it to boot in EFI mode by using Boot Repair in EFI mode or by installing rEFInd from OS X. The latter will change how you boot, though; instead of holding down Alt to select your OS, the rEFInd menu will appear automatically on every boot and enable you to pick your OS.


How to disable program switching (alt+tab equivalent) with the mouse?

If you want to keep two finger scrolling on but COMPLETELY DISABLE THE ALT-TAB FEATURE you'll want to do this, (found at: http://ubuntuforums.org/showthread.php?t=2211863, the forum post was made to do something slightly different, but can be applied to this issue)

sudo apt-get install compizconfig-settings-manager
sudo apt-get install compiz-plugins

Open compizconfig-settings-manager with alt-F2, type

ccsm.

Scroll down to "Ubuntu Unity Plugin". Choose the tab "Switcher". Disable the alt-tab and shift-alt-tab key bindings. I went ahead and disabled everything, but you don't have to.
Now this super annoying glitch is gone YAY : )


Getting a syntax error when I type pthon on Ubuntu 18.04

The error you are getting is consistent with trying to run the python3.6/site.py file using python2.7:

$ python2.7 /usr/lib/python3.6/site.py
  File "/usr/lib/python3.6/site.py", line 183
    file=sys.stderr)
        ^
SyntaxError: invalid syntax

Since python2.7 is still the default for Ubuntu 18.04, you should avoid setting your PYTHONPATH to a python3-specific value.


Display tearing & flickering, Amd R9 270x

Do check to see if you can reproduce the isse with another cable Hdmi or display port.

On Graphic card is it DVI-I Dual-Link, DVI-D Dual Link, HDMI, or Display port.
On Screen is it DVI-I Dual-Link, DVI-D Dual Link, HDMI, or Display port.

I love DVI but they have an egregious tendency to bend pins and this transmits from male to female like an std so if you flip the cable over three times both screen and graphic card and both sides of the cable will all have the bent pins and openings where two pins try to fit in one opening.

it's sublte so it's hard to notice but it will cause this type of flickering quite exactly.

you can bend the plastic of the bent opening in the female back into shape and you can also bend the bent pin on the male back into position.

if the issue persists with other cables and ports it probably is a driver issue of sorts I'd recommend seeing if the issue exists with fedora 25 or other (windows if that's an option).

I'd have suggested the AMDPRO GPU driver but it looks like your graphics card isn't on the support list.

that's all i've got hope this helps.


SFTP Can view directory but cannot write

Some simple potential fixes
Make User Account on Host Machine
On the host machine where the /home/FTP directory is located, make sure that <username> has a User Account and password.
Make User Owner of Directory on Host Machine
On the host machine where the /home/FTP/<username> directory is located, make <username> the owner and group of this directory, recursively:
chown -R <username>:<username> /home/FTP/<username>

-R, --recursive        operate on files and directories recursively


How to get an Ubuntu 18.04 server to automatically reconnect to network after reboot?

This solved it:

  you've probably confused the netplan calendaring tool with netplan the
  network configuration tool install netplan.io not netplan

(sudo) apt install netplan.io netplan-


My Ubuntu Touch seems to be broken no matter how many different files I try

Just that specific daily image had some broken features, and my misunderstanding on lots of things.


The plan from your ISP is your bandwidth , which you said is 100Mbps.
Your download speed is roughly around 1/8th of your bandwidth.

Edit: This line doesn't mean you get 1/8th of what you paid for. You
are getting the full bandwidth. Its just that the units have changed.
Your download speed and bandwidth are measure in different unit. Take
a guess which one your ISP uses to advertise its plans? The one which
makes their plan look good. Its like measuring the vehicle speed in km
and mile. Your dealer will advertise top speed in km/hr but your car meter will show you speed in miles. (just imagine this scenario, i know that is not how it works with cars). Its almost like this example.

Your download speed will never be the same as your bandwidth.  Download speed depends on various factors.

Download server: if the server that the file is being downloaded has capped download speed for that file at lets say 1Mbps then you will never be able to download that file at higher speed. Irrespective of your bandwidth.
Multiple Thread downloads: If your download manager supports it then you can take example 1 and create 10 connection to that server and download that same file at 10x speed. But this like I said your download manager needs to support this. I am not sure if firefox download manager supports this or not. Try using some other download manager.
Then there are other factors like your computer. Is it capable of downloading large files at that speed? If your network card drivers are not up to date then it might be the reason behind slow speeds. Is there some other software that's using the bandwidth as well?
Your router plays an important part as well. The Wi-Fi band you are connected to, distance from your router. Other devices connected to the router and their data consumption as well.

So as you can see, its mix of all these things and few more that determines your download speed or internet speed. And like I said, your internet speed is not the same as your bandwidth. You can easily find numerous articles and videos on the internet explaining the difference. But if you are getting that much speed on steam then you are getting good speed as per your bandwidth.


What file system fomat should I choose in Windows 8.1 disk management for my partition to install ubuntu 14.04.3 amd64?

Installation Media
After freeing up the space I would suggest not creating a partition. When you boot from the installation media and install Ubuntu it will create all the necessary partitions: /(root), swap...

I would suggest you boot into windows at least once after changing the partition size and before installing Ubuntu. This way you can make sure the partition re-sizing worked without a glitch. I know of users that blame Ubuntu for not being able to access Windows but the problem arise from an incorrect partition re-sizing process.

Also use ext3, the newer standards let you use more space and have files of greater size. Even better, use ext4 if possible as it is more recent and has more options. The installation media however will make that choice for you if you use it.


Is there a 64-bit version for Intel systems?

amd64 is equivalent to x86_64, is the 64-bit version of the x86 instruction set. Intel called it Intel64 initially.

Different distros use different naming, a bit confusing but in fact they are the same thing. Debian uses amd64 (that's why Ubuntu uses the same) while Fedora, Arch Linux use x86_64. Don't worry;-)


After upgrading Lubuntu from 17.04 to 17.10, "Software & Updates" does not work properly

I finally found the answer to this problem. For some reason, after the upgrade, the PolicyKit Authentication Agent was removed from my list of Startup Applications. I found the solution here.


OpenVPN auto-reconnect after network down in Ubuntu 18.04

In terminal, type nm-connection-editor, and select your wired/wireless connection profile, and edit like this...


Try this
sudo apt-get purge xfconf xfce4-utils xfwm4 xfce4-session xfdesktop4 exo-utils xfce4-panel xfce4-terminal  thunar

followed by
sudo apt autoremove


How do I set resolution to 1440x900 with Nvidia?

You can try this:

What you can do is install a newer version of the Nvida Drivers. Click the link below to download the latest drivers from Nvidia's Website:

Linux x64 (AMD64/EM64T) Display Driver

Download it and now follow this this tutorial on how to install it. I would suggest you read all this on another computer, as the one that you will perform the install on will not be working for internet viewing.

After you are done, try again to change your resolution.

Good Luck. Hope this works for you! Let me know if it works.


Is there a way to change the position of the top menu bar?

Sorry but changing the menu bar position is not possible in unity desktop environment. It is designed to be same on all systems.

But If you need customization, you may try other desktop environment like gnome-shell, gnome-classic-desktop, KDE etc. In gnome you can easily drag it using "super+alt".


Make/Remove USB Storage Devices as Read Only

Try remounting the device with rw access by:

sudo mount -o remount,rw <mount-point-of-/dev/sdb1>


BTRFS is and will be for the time being in development. This is being shown in the BTRFS FAQ page:

Is btrfs stable?

Short answer: Maybe.
Long answer: Nobody is going to magically stick a label on the btrfs code and say "yes, this is now stable and bug-free". Different people have different concepts of stability: a home user who wants to keep their ripped CDs on it will have a different requirement for stability than a large financial institution running their trading system on it. If you are concerned about stability in commercial production use, you should test btrfs on a testbed system under production workloads to see if it will do what you want of it. In any case, you should join the mailing list (and hang out in IRC) and read through problem reports and follow them to their conclusion to give yourself a good idea of the types of issues that come up, and the degree to which they can be dealt with. Whatever you do, we recommend keeping good, tested, off-system (and off-site) backups.
Pragmatic answer: (2012-12-19) Many of the developers and testers run btrfs as their primary filesystem for day-to-day usage, or with various forms of "real" data. With reliable hardware and up-to-date kernels, we see very few unrecoverable problems showing up. As always, keep backups, test them, and be prepared to use them.

This also applies to Ubuntu implementation of BTRFS.


Error authenticating some packages while upgrade

Important Security Notice

  This answer will disable an critical security feature in Ubuntu. It will stop Ubuntu checking packages are the the same as they were when they were built.

  This could mean your updates are compromised or corrupt.
  This could mean there's just a bug in the way Ubuntu's release upgrades are handled.

  I'm not saying you should never do this, I'm just asking you to be aware of what you're doing. And put things back after you upgrade. Don't leave AllowUnauthenticated on indefinitely.

  — Oli, Ask Ubuntu mod.

This worked out for me.

create the file  /etc/update-manager/release-upgrades.d/unauth.cfg as root and add the following.

[Distro]
AllowUnauthenticated=yes

After upgrade, remove this file.


Help with Wifi problem on Acer Aspire One 532h update to 11.10

Here's how to fix this if your hardware is bcm4312 you just need the correct firmware

open terminal and type:

sudo su -

apt-get install firmware-b43-lpphy-installer

apt-get remove --purge bcmwl-kernel-source

apt-get autoremove --purge

the last one will clean dependency created by bcmwl << which is the STA driver.

reboot - and you-re done.


Delayed touchpad scroll event causes crazy zooming if top of the page is reached

It seems like I'm not the only one [1][2] concerned with that issue and that is a Xor bug.

The only workaround I found which kind of works is this extension for chrome.

UPD Extension does not seem to work properly with last version of chrome, but doing synclient CoastingSpeed=0 seems to handle everything perfectly for me without any negative side effects.


To run it, simply extract the downloaded archive and double click the "airnef" executable.

For Linux 32bit (also works for 64bit obviously, if you prefer using the python source instead of the binary), firstly install python-tk by running

sudo apt-get install python-tk

once you installed python-tk, In the folder where you've extracted it, run the following command to start the application

python airnef.pyw

Hope it helps


How to load a `zenity` List Dialog with space-embedded data from `ls`?

You can pipe the list content into zenity, like

(echo "How much wood would a woodchuck chuck," ; \
 echo "if a wooodchuck could chuck wood?" ; \
 ls -Q -1 "$zenlist"* |sed 's/$/ \\/') \
| zenity --list --title='A single-column List' --width=600 --height=450 \
         --column='Spaces are allowed within "q u o t e s"'


Dell XPS15 L502x Mini Display Port not working Ubuntu 13.04

Found the solution:

xrandr --addmode DP1 1920x1080
xrandr --output DP1 --mode 1920x1080 --right-of LVDS1

works like a charm


I don't think you can add icons like you used to in Gnome 2.
An icon ends up there if it's a notification.
You can add icons to the Unity's dock (on the left), by right clicking on an open application's icon, and selecting "lock to launcher"

This link might be helpful:

What Application Indicators are available?


This has been asked in many places.  You need to change SSD controller setting in BIOS from RAID to AHCI, or Linux won't find it.

But the downside is that you need to fix or re-install your Windows in AHCI mode.


How do I install Unity Web apps from the software repositories?

After you install a WebApp, it doesn't get added to your Unity Launcher like normal applications do. You actually have to visit the website in your browser and enabled/install it on that website. When you visit a website supported by or supports WebApps, you should get a little option bar or panel that asks you if you want to install or enable WebApps for that website. Once you click yes, you should see the icon appear in your Unity launcher and Dash. If you don't get an option bar/panel then most likely you have the website blacklisted.

Remove an “excluded” WebApp website in Firefox:

Go to Edit – Preferences – General
Under “Desktop Integration” click the Exceptions button
Make sure the website you are trying to use is removed from that list.
Restart your browser and revisit the website.

Note, by default, Firefox is the only browser that supports Unity WebApps; however, you can install an extension to allow Chromium to work as well. I believe the package name is: unity-chromium-extension.


'htop' does not show the correct CPU%, but 'top' does

As you've said yourself, you can hit H to show user threads.

Just for future reference (and for fun), let's calculate CPU utilisation!

A bit of background:

In a modern operating system, there's a Scheduler. It aims to ensure that all of the Processes and their threads get a fair share of computing time. I won't go into scheduling too much (it's really complicated). But in the end there is something called a run queue. This is where all the instructions of all of the processes line up to wait for their turn to be executed.

Any process puts it's "tasks" on the run queue, and once the processor's ready, it pops them off and executes them. When a program goes to sleep, for example, it removes itself from the run queue and returns to the "end of the line" once it's ready to run again.

Sorting on this queue has to do with the processes' Priority (also called "nice value" - i.e. a process is nice about system resources).

The length of the queue determines the Load of the system. A load of 2.5 for example means that there are 2.5 instructions for every instruction the CPU can deal with in real time.

On Linux, by the way, this load is calculated in 10ms intervals (by default).

Now onto the Percentage values of CPU utilisation:

Imagine you have two clocks, one is called t and it represents real time. It measures a second for every second. The other clock we call c . It only runs if there is processing to do. That means, only when a process calculates something does the clock run. This is also called CPU time. Each and every process on the system 'has got' one of those.

The processor utilisation can now be calculated for a single process:

or for all processes:

On a multi core machine, this may result in a value of 3.9 of course, because the CPU can calculate four seconds worth of computation every second, if utilised perfectly.

Wikipedia provides this example:

  A software application running in
  6-CPU UNIX machine creates three UNIX
  processes for fulfilling the user
  requirement. Each of these three
  processes create two threads. Work of
  software application is evenly
  distributed on 6 independent threads
  of execution created for the
  application. If no wait for resources
  is involved, Total CPU time is
  expected to be six times Elapsed real
  time.

Here's a small python snippet that does this

>>> import time
>>> t = time.time()
>>> c = time.clock()
>>> # the next line will take a while to compute
>>> tuple(tuple(i**0.2 for i in range(600)) for i in range(6000))
>>> print (time.clock() / (time.time() - t)) * 100, "%"
66.9384021612 %

In a perfect world, you could infer from this that system load is 100 - 66.93 = 33,1%. (But in reality that'd be wrong because of complex things like I/O wait, scheduling inefficiencies and so on)

In contrast to load, these calculations will always result in a value between 0 and the number of processors, i.e. between 0 and 1 or 0 to 100%. There is now no way to differentiate between a machine that is running three tasks, utilising 100% cpu, and a machine running a million tasks, getting barely any work done on any single one of them, also at 100%. If you're, for instance, trying to balance a bunch of processes on many computers, cpu utilisation is next to useless. Load is what you want there.

Now in reality, there is more than one of those processing time clocks. There's one for waiting on I/O for example. So you could also calculate I/O resource utilisation.

This may not have been helpful regarding the original question, but I hope it's interesting. :)


Will installing TLP noticeably change Ubuntu?

From what I've read, It looks like TLP will disable WiFi and Bluetooth until needed, and it also controls brightness.

Quick answer: yes.


You will potentially have to upgrade your kernel to a newer release in order to get the full Thunderbolt3/USB-C functionality.

The port is capable of both USB and Thunderbolt functionality, but the Linux kernel drivers are still catching up.

Getting to use a Precision 5510 for work since May and working on the imaging process (preseed) I learned that we are using a specific version of the 4.10 kernel in order for the TB3 to work properly with the Dell TB15/TB16 docking stations. It seems like things are hit or miss when updating to the Ubuntu hwe-edge (their semi official 4.10 packages) and the version we are using is closer to mainline than to an Ubuntu build.

I've been deploying the spare 5510s that I was testing on to users, but I'll try a fresh install with the hwe-edge again and see if it works properly with the docks. The USB-C support has been pretty solid, but not everything is back ported to the 4.4 kernel.

Update:

Ubuntu 18.04 and the 4.15 kernel is WAY better than 16.04 and any of the supported Ubuntu kernels available there. Possibly in 16.04.5 with the linux-image-hwe-edge-16.04 if it is 4.15 it will be better in 16.04, but there are some excellent improvements with 18.04 all around, not the least of which includes not needing to limit the Gigabit Ethernet port of the TB15/TB16 to 100 Megabit due to an overflow issue in the drivers.


What combination of bluetooth mouse and keyboard work ok with the BQ M10 tablet?

I personally use HP X4000B - mouse & Logitech Bluetooth Multi-device Keyboard K480, I've found both to be extremely reliable


How to improve Ubuntu performance on netbook

I know this is an old question, but I had similar problems on my Samsung netbook and maybe the described steps will be useful to someone.
My netbook is an old machine and Ubuntu 12.04 was too slow to be useful. I tried several tweaks, which improved things, but not enough.

I didn't feel like replacing Ubuntu with Lubuntu and then installing all the software that I like in Ubuntu.

So I did the following:

installed the lxde core desktop - this installs the desktop, but not all the other software - I used these instructions: http://complete-concrete-concise.com/ubuntu-2/ubuntu-12-04/ubuntu-12-04-how-to-install-the-lxde-core-desktop
installed lxterminal (so that I can start the terminal with ctrl+alt+t shortcut, there is a way to map the shortcut to point at the Ubuntu terminal, but I found this solution to be simpler)
installed "synaptic package manager" (it's much faster then Ubuntu software center)
installed "synapse" as the launcher, so I can use it instead of the searching in dash
moved the window close, maximise and minimise buttons to the left according to the instructions here: http://www.lubuntutips.com/2012/07/moving-close-maximize-and-minimize.html#.UI09auBuHXY

I really like Unity and I use it on my desktop computer. And while the above doesn't allow you to use some cool features such as the global menu and HUD, I find it's a very good compromise. Everything now works really, really fast.


Lost gimp 'recent document list' after Ubuntu upgrade

There is only one list of recently used files, which is used by Gimp and many other apps. It is ~/.local/share/recently-used.xbel. If you open a file with Gimp (or any other app that supports the recently-used file), the file name will be added to recently-used.xbel. You may have a backup copy of that somewhere. Otherwise, you could recreate it by editing the current file recently-used.xbel and adding an entry for each Gimp file you want to have available. Such an entry would look like this:

  <bookmark href="file:///path/to/file" added="2015-09-05T10:28:53Z" modified="2015-09-05T10:36:40Z" visited="2015-09-05T10:28:54Z">
    <info>
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debconf hanged on 13.04 to 13.10 upgrade path to Tahr

From a terminal I first killed the 23642 process I beleived as a subprocess, but this didn't help as the dimmed window was still here. Then I used xkill from the terminal over the dimmed window which closed ok, freeing the installation to run up to its end. Before rebooting I went to /etc/default/ and found grub, grub~ (an old backup), grub.me (my fresh backup) and a grub.something.threeway or so. I just had to make all that stuff clean. BTW, I must add more info: I never selected the three way compare. More, in a first step I choose the first option (in my memory) and I noticed the compare option was not the one I selected. So I suspect there is a bug in the handling code.


None of the existing answers is incorrect, but similarly don't explain why you're having the problem you are, or how to fix it. Let's clear up some things:

zlib is a builtin, not a packaged thing. Virtualenvs are great things but won't help here.
If you don't have it, it wasn't built when Python was built.
You need the zlib development libraries in order for Python to be linked to it. If the ./configure step can't find it, it'll disable it from your build.

So that having been said, sudo apt-get build-dep python2.7 will be the sanest, quickest way to get all the build dependencies for a "typical" Python build.

But then you need to reconfigure, recompile and reinstall your version of Python. Just installing the build requirements won't retroactively link it in.


Laptop connecting to wifi, but not internet

Besides not having the proper password entered for your home network, the other slightly-more-remote answers could be that:

your home wifi is using an unsupported WEP authentication method. WPA and WPA2 are the commonly supported protocols;
your wifi connection on the laptop is using a fixed IP address that is not in the same IP range as your home network. Are you using DHCP on the wifi connection?


Getting Ubuntu Touch on my Phone (toroplus, Galaxy Nexus Sprint)

The toroplus appears to be one of the two CDMA variants of the Galaxy Nexus.  The ubuntu-system images currently only support the GSM variant of that handset (maguro), which explains the error.

It looks like someone in the community ported one of the early phone images to toroplus, but it doesn't look like it's been updated in about 8 months:

https://wiki.ubuntu.com/Touch/Devices/toroplus

It also says that the actual phone functionality doesn't work on that image (an area where the CDMA version differs from the original GSM one).  More information can be found in the forum thread on XDA Developers:

http://forum.xda-developers.com/showthread.php?t=2159832


Trying to launch application in full screen mode on boot

Try to run xbmc in the background:

#/bin/bash
xbmc --standalone &
sleep 5
wmctrl -r XBMC Media Center -b toggle,fullscreen

In your script, the "sleep 5" command only runs after you quit XBMC.