qtcreator 3.5.1 (Qt 5.5.1) crashes on Ubuntu 14.04, VritualBox Could not initialize GLX Aborted (core dumped)

I got the same problem.
ubuntu 14.04LTS under virtualbox 5.0.4

https://stackoverflow.com/questions/34654638/qt-creator-doesnt-launch-in-linux-mint-for-qt-5-5-1
Desativating 3D acceleration for display in VirtualBox worked for me.

Regards


How to 'chown' on an NTFS ( or FAT32 ) partition?

I suspect your NTFS partition gets automatically mounted at boot. If we were speaking about i.e. a USB disk you attach to your computer, the permissions would be set correctly when you click on the volume in your file manager.

So there is probably an entry in your /etc/fstab file which looks like this:

...
someWeirdId  /media/name  ntfs  auto,stuff,stuff,stuff  0  0

change this to:

...
someWeirdId  /media/name  ntfs  auto,stuff,stuff,stuff,uid=1000,gid=1000,umask=0000  0  0

This gives ownership of the mounted volume to the user with uid 1000, which would be the first user in your system. Enter id on a terminal to see what uid and gid you have.

Setting umask to 0000 should grant all permissions to every user anyway.

NTFS and FAT cannot store posix permissions, like they are used by Linux (actually i'am not sure about NTFS, but I wouldn't know how).

However you can use the program fuse-posixovl to mount a directory (!) on any partition (regardless if posix permissions are suipported or not) to another directory (or the same directory if you feel like it). posixovl will create a file on the real filesystem storing the posix permissions you set in the other mountpoint. This way you get full posix functionality on any non-posix file system.

To be able to change file ownership, etc. you should run posixovl as root (via sudo).

sudo mount.posixovl /directory/on/ntfs/partition /directory/where/i/use/chown

As I said source and target directories can theoretically be the same, but try it with different directorys first, just to be sure.

The permissions will not be effective unless posixovl is used. So you can't protect your data when you attach the disk to friends computer or something. The files will be accessible anyway.


dependency problems prevent configuration of energytycoon

libois-1.2.0 is an obsolete package and has been replaced in recent versions of Ubuntu by libois-1.3.0.

If you need the old version you can still try to install it using sudo dpkg -i <deb_file>.

The deb package can still be downloaded from launchpad: amd64 or i386.

Example for amd64: sudo dpkg -i libois-1.2.0_1.2.0-2_amd64.deb


How to reboot ubuntu server machine from outside

when u have this error :

ssh: connect to host port 22: No route to host

you can't reboot it without beeing physically there.

That's why my ubuntu servers are always Virtual Machines, so i can reboot them if something happens. Of course if my server crashes i can't do much, but calling my wife to reboot it :)


How to change grub2 keylayout on Samsung laptop

Your /etc/grub.d/50_keyboard looks like it might be incorrect.

\#!/bin/sh
exec tail -n +3 $0
\# Clavier fr
insmod keylayouts
keymap /boot/grub/layouts/fr.gkb

the exec line with +3 looks wrong. But rather than change it... or renaming it to 39_keyboard and fixing the exec line...

delete /etc/grub.d/50_keyboard
edit /etc/grub.d/40_custom

Add this to the END of this file:

insmod keylayouts
keymap /boot/grub/layouts/fr.gkb

so that the final file looks like:

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
insmod keylayouts
keymap /boot/grub/layouts/fr.gkb


Gnome Shell problems when upgrading from 12.04 to 12.10

This is a change in design for gnome-shell 3.6. It's a bit awkward, yes, but the new version of gnome-shell (3.8, to be released in the next 4 months) will change the behavior slightly.

In the mean time, check out https://extensions.gnome.org/extension/495/topicons/


How to fix Totem's "Invalid Commandline" error?

I ran into the same problem as you did. So I tested my video playback (mp4, h264) with VLC and it worked very well. But I wasn't able to have Quicktime playback in Firefox with the mozilla-plugin-vlc and browser-plugin-vlc.

So my advise to you would be to use mplayer with gecko-mediaplayer. This solves all my problems.


Ignoring file 'libdvdcss.lis' in directory '/etc/apt/sources.list.d/'

apt-sources in the sources.list.d directory need to end in .list.

When in doubt... look at man sources.list, and you'll find the following:

  The /etc/apt/sources.list.d directory provides a way to add sources.list entries in separate files. The format is the same as for the regular sources.list file. File names need to end with .list and may only contain letters (a-z and A-Z), digits (0-9), underscore (_), hyphen (-) and period (.) characters. Otherwise APT will print a notice that it has ignored a file, unless       that file matches a pattern in the Dir::Ignore-Files-Silently configuration list - in which case it will be silently ignored.


Nexus 4 with Ubuntu touch locked for 24140377 minutes!

Is your device in developer mode?

If yes, you could first try copying your home directory, then reset your device, and finally write your home directory back to your device.

edit:

So here are some instructions (untested) how you could backup your home directory:

PlugIn your device via usb to your desktop computer.
run adb devices; Your device should now be listed, if it is in developer mode.
run adb pull /home/phablet/. /home/userName/your/backupDir/. to download the home folder to your pc.
Make a coffee until its done...
Now you might want to know where your notes are placed? I had success on searching them with this command: grep -r "Some pattern you remember of your notes" /home/userName/your/backupDir/. The output shows the file(s) containing your pattern, i. e. your notes-data-file.


Does Ubuntu remembers installed softwares in the trial mode from Pen Drive

Depends on whether you created a USB drive with persistence enabled. If you did, packages and settings will be there the next time you use it.

If you didn't, the official documentation can help you create a Live Ubuntu with persistence mode.


First, look at gnome-system-monitor for realizing what's going on. But I think You must install Lubuntu(LXDE based Ubuntu). You can get much higher performance with it on 2GB RAM with a dual core processor.

The difference is just the look. You can run everything that works under default Ubuntu


Accidently deleted "Setup" entry from Samsung UEFI boot menu. How to get it restored?

Solved by removing all entries using efibootmgr and removing the boot order.

This caused the Samsung NP900X3C-A07DE notebook to restore the system defaults for the EFI boot menu.


Ubuntu 17.04 multitouch gestures are not working on Macbook pro

I'm having similar trouble on the (upgrade) install, but it worked fine from the live usb. Single touches are working fine (i.e., the screen is okay).


How to install additional packages that had ignored by --no-install-recommends flag?

From the official Debian package management page:

  "Recommends"

  This declares a strong, but not absolute, dependency. Most users would
  not want the package unless all of the packages listed in this field
  are installed.

  "Suggests"

  This declares a weak dependency. Many users of this package may
  benefit from installing packages listed in this field but can have
  reasonable functions without them.

To install the packages ignored by the --no-install-recommends flag, you can consider this nice trick suggested by Gilles (you'll need the .deb package though). The other option is to remove and install the package once again, this time without --no-install-recommends.

If you think why apt-get install --reinstall --install-recommends doesn't install these packages, here's an explanation.


How do I set up file sharing between two Ubuntu laptops on my wireless network?

Share files between 2 Ubuntu computers

If you have two computers running Ubuntu on the same network, it would be an good idea to use openssh to share files between them.

On the server (the computer with the files you want to access), run:

sudo apt install openssh-server

On the client you should have ssh installed already (if for some reason it's not install, run sudo apt install openssh-client).

Then you need to figure out the IP of the computer you want to connect to. Most of the time it's something like 192.168.1.x. To find out the IP, run ifconfig and look for the "wl..." interface (or "eth..." if you're connected over Ethernet cable).

On the client, open Nautilus (Super+E) and go to “File -> Connect to Server”.

Enter sftp://<the_IP_of_the_server>

On older version of Ubuntu, you could pick the folder you wish to share. As of Ubuntu 16, if you don't specify a path after the IP, you'll get the home directory. For a specific directory outside of the home dir of the user you're connecting as, you need to type its path.

Note that it could take some time to connect, depending on the size of the folder directory.

You'll be prompted for the user/password of the computer you want to connect to.

The name of the directory will become a bookmark in Nautilus.

You should have read/write permissions.


Can I alt-tab windows from all workspaces?

In 12.04, the switcher defaults to those windows co-located on one workspace/viewport.

You have a couple of options in ccsm

You can untick the bias option which will show windows in all workspaces.

Alternatively, you can use add CTRL to your ALT+TAB to achieve the same effect


Ubuntu 14.04 bluetooth paired but not listed as an output device

I notice one thing missing from the pactl list short results

sudo pactl load-module module-bluetooth-discover

Then redo the pairing and see if the device shows in sound settings


Cannot connect to the Internet on Ubuntu

Try different DNS settings: 8.8.8.8 and 8.8.4.4 (short guide here, may be a little outdated but should work: http://ubuntuforums.org/showthread.php?t=2078398)

Also make sure your subnet is correct.  I manage over a ton of networks at my day job and a mistyped subnet can cause all sorts of problems.


How to keep python virtualenvs while updating ubuntu?

I had the same issue when upgrading to Ubuntu 20.04. The reason is that Python 3.6 and 3.7 are no longer included in the system packages. If you've created a virtual environment for 3.6/ 3.7 using virtualenv, it still expects a matching system interpreter. You can install these Python versions via the deadsnakes PPA in Ubuntu 20.04:

sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt update
sudo apt install python3.6 # and python3.6-venv, python3.6-dev if needed

In many cases, this won't suffice: Check ls -la| grep python3 in your venv/bin-directory and you'll see links like:

lrwxrwxrwx 1 me me    16 Mai 10 16:20 python -> /usr/bin/python3
lrwxrwxrwx 1 me me     6 Mai 10 16:20 python3 -> python
lrwxrwxrwx 1 me me     6 Mai 10 16:20 python3.6 -> python

This environment links against the default Python instead of specifically linking against Python 3.6. You'll need to change the base link like this:

ln -sf /usr/bin/python3.6 python

Then, the environment should continue to work. I haven't tested it myself though and just upgraded my environments instead.


Make Xbox One controller work without new kernel

Yes.

Build your own kernel, starting with your current version. Then step through each source change between that version and the version with Xbox support. Apply it or not, depending on your decision as to the change's contribution to "Xbox support" or "breaks Nvidia". Be sure to test frequently.

This is probably more work than you want to do.


gnome-control-center not found but installed

It turns out that doing apt remove gnome-control-center and apt install gnome-control-center fixes this.

However when launching from terminal a Gtk message "Failed to load module 'pantheon-filename-module'" appears, so perhaps indicating an incomplete or incorrect clean-up.


Numbering paragraphs with the 'cat' command

If the paragraph is actually a line like your example, and you have to use only cat, then surely you want -b (number non-empty lines)?

cat -b file

looks like:

     1  Frederick II (German: Friedrich; 24 January 1712 – 17 August 1786) was King of Prussia from 1740 until 1786.[1] His most significant accomplishments during his reign included his military victories, his reorganization of Prussian armies, his patronage of the Arts and the Enlightenment in Prussia, and his final success against great odds in the Seven Years' War.

     2  Frederick was the last titled King in Prussia and declared himself King of Prussia after achieving full sovereignty for all historical Prussian lands. Prussia had greatly increased its territories and became a leading military power in Europe under his rule. He became known as Frederick the Great (Friedrich der Große) and was affectionately nicknamed Der Alte Fritz ("Old Fritz") by the Prussian people.

To save this in a file instead of printing in the terminal:

cat -b file > file2

In case you really need them, you could add the dots after your numbers, though not, afaik, without resorting to using another command to help cat, like sed, which here replaces whitespace and numbers in lines that start with them (since cat -b indents) with the same pattern plus a . to make 1. 2. etc (this was suggested by @terdon so blazingly fast I didn't have time to make it myself & take the credit)

cat -b file | sed -r 's/^\s+[0-9]+/&./' > file2


Are there any good programs to learn Dvorak?

I learned Dvorak using TypeFaster for Windows.

On Linux, ktouch is supposed to be very good, or there is gtypist if the others aren't suitable.

KTouch comes with a configuration file called sv.dvorak.keyboard, so I think it will work for you.

See also: https://superuser.com/questions/541/is-there-any-software-to-help-me-learn-the-dvorak-layout

UPDATE

sv.dvorak is supported in older versions of KTouch.  To get it to work in the current version, try this:

Download http://sourceforge.net/projects/ktouch/files/ktouch/1.6/ktouch-1.6.0.tar.gz/download
Open ktouch-1.6.0.tar.gz
Navigate to /ktouch-1.6.0/ktouch/keyboards/
Click on sv.dvorak.keyboard
Extract...
Save somewhere (e.g. ~/Downloads)
Follow these instructions http://edu.kde.org/ktouch/kde4/keyboards-layouts.php


Ubuntu 18.04, standard Ubuntu Dock, multiple action syntax in .desktop file

The .desktop file in ~/.local/share/applications had to be named "org.gnome.Terminal.desktop" instead of "gnome-terminal.desktop". Otherwise there were two icons for the gnome-terminal in the dock.


You have two problems:  (1) Carriage returns, and (2) incorrect paths.
Carriage Returns
Your script has extra carriage returns which are messing up handling of the script, because the system is trying to execute /bin/bash^M directly - which doesn't exist, because it can't; ultimately this is because you edited the script in Windows or wrote it in Windows.  This is commonly the case when you use Windows to make/edit Linux scripts.  So, don't create scripts in Windows that you intend to use on Linux.
That said, you can fix the problem.
Per this post on our sister site Unix and Linux you should try this specific solution:

Use dos2unix to format the file better.

Use dos2unix /path/to/script
If that doesn't work, use dos2unix -c mac /path/to/script

At least one of these solutions should remove the ^M carriage returns from the script and it SHOULD then work as expected.
Fix your paths
After you fix the carriage returns, /bin/bash is your executable, it's not a directory.  So your shebang line should be: #!/bin/bash

As for your Desktop errors (which needed to be added as an edit!):
use exo-open /home/oem/Desktop/Zoom.desktop to open the Desktop launcher file.


Network traffic throttling using tc/tbf - unexpected results

Timer resolution might influence your results, see here for example. What happens if you increase burst to 10kb and remove peakrate and minburst?


How to install dli-downloader into Linux?

First install JAVA

sudo apt-get install openjdk-7-jre

Then download dli-downloader with dependancies package, to your /home

wget https://dli-downloader.googlecode.com/files/dli-downloader-5.4-jar-with-dependencies.jar

Then you can run

java -jar ~/dli-downloader-5.4-jar-with-dependencies.jar

Dli-Downloader will now run

You can make a "clickable" executable by opening gedit and pasting this into a new file

[Desktop Entry]
Type=Application
Exec=java -jar ~/dli-downloader-5.4-jar-with-dependencies.jar
Hidden=false
NoDisplay=false
X-GNOME-Autostart-enabled=false
Name=Dli-Downloader
Comment=Runs Dli downloder

Save it in /home as

dli.desktop

Then make it executable

chmod -x ~/dli.desktop

Now if you click dli.desktop dli-downloader will start.


dconf is a new way for applications to store settings, and it is intended to replace gconf. dconf-editor and gconf-editor are for their respective configuration systems, and they don't talk to each other. At the moment that transition is still a work in progress, so many applications continue to use gconf. In addition, some applications still have settings left over in gconf even though they are using dconf now.

Almost all of the software that is installed by default - everything that comes from GNOME - uses dconf (if anything). Almost everything else that is available uses gconf, though this is of course changing as older software is brought up to date.

So, yes, changing a setting in gconf is likely to do something! If you did a fresh install of Ubuntu 11.10 and didn't migrate your gconf settings, it's likely that everything you see with gconf-editor is being looked at and understood by some current application. If your settings predate 11.10, there may be stuff there that isn't being used.

As a rule of thumb, check dconf first and if what you're looking for isn't there, try gconf.


How do I get the touchpad working on a Toshiba P850?

This issue is now resolved since a recent Ubuntu update.  Not sure which update it was but thanks guys & girls :)


You probably don't have libksba-dev installed. Install it:

sudo apt-get install libksba-dev


Put what you need to find inside double quotes

sudo find / -name ".avi" -print

(sudo if you want to search the whole disk).


How can I temporarily disable localhost access to a certain port?

Use iptables on the server, to stop it from sending packets to the client and from receiving packets from it:

sudo iptables -A OUTPUT -p tcp --sport 80 -j DROP

will prevent the server from reaching the client; and

sudo iptables -A INPUT -p tcp --dport 80 -j DROP

will prevent the client from reaching the server. sport stands for source port and dport for destination port.

This is completely independent from the tomcat server process, and it will look (to the client and the server) as if the connection was suddenly interrupted. I am reasonably sure this will work even if client and server are on the same host.

See what rules are currently in place with:

sudo iptables -L

Remove all existing rules with:

sudo iptables -F


How to delete an EFI partition on an External HDD without affecting other partitions?

Yes; using any disk partition editor, including gparted or the gnome disk utility.


Command for stopping program after some cutoff ram usage

You could use the bash 'while loop' to achieve this. Here is a simple script I wired up, that will exit if you run out of memory:

#!/usr/bin/env bash
set -x
set -e

state=$(sed -E 's/^[[:space:]]*([[:digit:]]*).*/\1/' <<< $(egrep --color 'MemFree' /proc/meminfo | cut -d" " -f2-))
check="2000000"

while [ "$state" -gt "$check" ]
do
    echo "Lots of memory"

done

echo "Out of memory"
exit 1

The script gets it's information from the '/proc/meminfo' file and checks for the free memory left. But of course modify to your needs.

Information:

set -x: used to debug the script.
set -e: stop script on first error.
state=$(sed -E 's/^[[:space:]]*([[:digit:]]*).*/\1/' <<< $(egrep --color 'MemFree' /proc/meminfo | cut -d" " -f2-)): get the free memory from '/proc/meminfo' file and format it for use.


The standard Ubuntu Nvidia drivers generate some problems on slightly older and slightly newer Nvidia hardware.

If you want more then the standard Ubuntu repository drivers, install the xorg.edgers PPA.  As the xorg.edgers group ask not to give installation instructions directly without linking to their page, this is the best I can do.

If you don't know what a PPA is or need some guidance after reading their page, leave a comment below.


what sort of license do you have? If academic on a campus-wide license you could raise this sort of question directly with MathWorks Support as they will be paying for System Services Maintenance (SMS). They will be better equipped to answer this question and usually respond within 24 hours or so.


Why is my Ubuntu 12.04 not booting after GRUB?

I found the answer through some digging around! All I had to do was disable secure boot from the BIOS I hope this helps anyone else!


Share between Ubuntu 18.10 machines without Samba

First, Samba works on Ubuntu as well as Windows, so it is not only for Windows machines.

It is also easy to get similar functionality with ssh. One way is to type sftp://serverhostname in the file browser's address bar (ctrl+l). That should prompt for username and password, and then open a file browser window into the server filesystem. Then you can copy/paste files.

PS: You may need to login once from a terminal windows so that the known host file is updated.


How to share Ubuntu desktop screen to a smart TV?

I've used HDMI and VGA connections to share my screen.  I usually extend rather than share.  This only works if your computer is close enough.  Relatively long cables are available.


Afterv upgrade of 11.10 to 12.04 my laserjet 5P did not work

Have you tried updating the packages since the upgrade to 12.04?

sudo apt-get update

in a terminal


Trying to Dual Boot Windows 7 and 12.04 using live DVD

If I was you I would get the 32bit version and see if that fails as well. It's very rare for a ISO image not to boot unless your computer is a very old model. I have booted from iMacs, MacBooks and regular PC's with no issues. Some old bios have issues booting from USB's but from a DVD is rare.

When you write the DVD, after you have burned it, pull it out and then stick it back into the computer to see if you see some files on the DVD, if you don't see any files it probably means you burnt it wrong. If you do see files add the list of the root directory to your question so we are sure that the files look ok...


Install software that uses a different shell

You can just start a bash shell in the ssh shell (whatever the default shell for ssh may be), or start it directly when sshing with:

ssh -tX USER@SERVER "bash -l"

This last approach however may not pick up your tcsh environment, if you want it to do that use the following command instead:

ssh -tX USER@SERVER "tcsh -cl bash"

Source: SSH then change Shell · SO


You need to give conjure-up the MAAS API credentials, not your login credentials.

Go to the MAAS GUI (as admin or a regular user), click on your name on the top right, select "account". There you will see "MAAS Keys". If it's empty, just generate one.

That's the text you need to give conjure-up, and is what it means by "3 items separated by colons": it's because the MAAS API key is like text:text:text.


VirtualBox Choosing a network adapter type

The choice of adapter is determined by VirtualBox based on compatibility of the guest OS.

In my own case, I'm running Ubuntu 17.04 Desktop as host, and Windows 10 as guest. VirtualBox chose the Intel PRO/1000 MT Desktop adapter, and it's worked well.

In your case, if you plan to run Ubuntu 17.04 as guest OS, VirtualBox should select, by default, the AMD PCNet FAST III adapter.


How can I set the resolution on a Dell 19 inch monitor to 1368x768?

Try this it will give you the latest drivers I could not use 1080p 60hz until I got the latest driver

Open a terminal and add the PPA

sudo apt-add-repository ppa:ubuntu-x-swat/x-updates

Then update the repos

sudo apt-get update

And finally update the drivers

sudo apt-get dist-upgrade

Now reboot, and when you log back in you will have a working, up to date nvidia driver in Ubuntu ;)

Heres the original post

Also make sure you are root in the nvidia settings

sudo nvidia-settings

Also make sure the two screens are separate X screens as your resolution will be limited to the lowest one (the laptop) if not.

Hope this helps and good luck.


While searching in the internet a bit, i found this.

n>&m    means redirect FD n to the same places as FD m. Eg, 2>&1 means send STDERR to the same place that STDOUT is going to.

STDIN is FD 0, while STDOUT is FD 1, and STDERR is FD 2

ref: http://www.linuxsa.org.au/tips/io-redirection.html

File descriptor 5 is sometimes used because it is the lowest numbered file descriptor that was never really used for anything else (FD 4 was /dev/tty on some very old unixes and FD 3 has had various, non-standard, system specific, uses in another Unix). Although since neither 3 or 4 have been used in over 2 decades it is probably just coincidence (or tradition) that you have noticed FD 5 popping up.

ref: http://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/File-Descriptors.html

As to the reason it is used. By using a file descriptor the script-writer avoids the need to actually write to a file, which could save him time and make the script cleaner (no possibility of accidently leaving around files). Furthermore it lets you do all the cool things with redirecting streams to different locations and so on.


Providing SSH tunnling, what to think about when configuring Ubuntu Server

Start by setting up required key authentication and disable use of passwords in sshd. The most common attack on Internet attached ssh daemons are password brute force attacks. The simplest way to counter such an attack is disabling passwords for sshd.

Check your /etc/ssh/sshd_config for the following settings:

PermitRootLogin no
PubkeyAuthentication yes
PermitEmptyPasswords no
ChallengeResponseAuthentication no
PasswordAuthentication no
UsePAM no

Don't forget to restart sshd: /etc/init.d/ssh restart.

When fiddling with sshd_config from a remote machine, make sure you have an extra session logged in, just in case you made a typo you can still access the server.

Also the advantage of /usr/sbin/nologin instead of /bin/false is that you actually get a short message as user that logging on to a shell environment is not permitted. Unsure if you can still set up tunnels.
BTW the documentation for OpenVPN2 is pretty good and if you can run through firewalls, you can probably run OpenVPN2 too.

Check out this sslh project which allows you to run a common webserver and ssh (or openvpn for that matter) on the same port! http://www.rutschle.net/tech/sslh That way you can 'hide' your ssh server behind a proper webserver ;o)

Last but not least: Check out proxytunnel, which enables you to run SSH over HTTPS which fools even more firewalls.

Notice though that a security officer may very well be extremely un-amused when he/she finds out that you are using these tools (ssh over port 80 or 443, proxytunnel, openvpn) to squeeze through a corporate firewall to access unsupported services. In many companies you can get fired for that.


Have you tried removing the existing compiled keybindings?

sudo rm /var/lib/xkb/*.xkm

Then, restart.

Credit: Why did 13.10 break my custom keyboard layout?


How to disable account logoff when closing lid of laptop

Is there a way to ... completely disable the logoff when closing the lid ...?

Which operation system do you use exactly?
For me with ubuntu 16.04 LTS I could handle the logoff issue with following standard system settings:

Turn off the Lock
system settings > Brightness & Lock > Lock: OFF
(Details here)
Maybe in addition you need to switch on "Automatic Login" for your user:
  system settings > User Accounts > Automatic Login: On


can't boot the Live DVD in my pc (UEFI, windows 8 dual boot)

The Ubuntu-Secure-Remix ISO has been updated yesterday. You may want to check the md5sum of your downloaded file.
Some users report they cannot boot the Ubuntu DVD in UEFI mode. Please setup your firmware in Legacy mode (in your first picture, change the Boot Mode option from UEFI to Legacy), then try to boot your DVD. You should see the menu below:

if you see this menu, then install Ubuntu normally. At reboot you will probably have no access to Windows, but the Boot-Repair's Recommended Repair should fix this issue.
if you don't see this menu, then try the development Ubuntu amd64 iso (it comes with a newer kernel), you can find it here: http://cdimage.ubuntu.com/daily-live/current/


Gstreamer videosink configuration error when playing videos with Parole

If you are getting the "Gstreamer backend error: Configured videosink video is not working." message, then you can try to run in the command line the following, only once:

parole --xv false

This solution was suggested in this related Ubuntu forums gstreamer videosink error thread.


After you plug the device in you may need to press the sync button on one or both the device and receiver. I have used multiple Microsoft based wireless devices, keyboard and mouse and they have always worked fine. In fact, you should be able to use a single receiver plugged into a USB port for both devices as they should be intercompatible.


Did you use xset fp+ /usr/share/fonts/truetype/mynewfont to add the directory to the font path?   (That only lasts for the life of the current X session though, doesn't permanently add the font paths.)


Change Apache document root folder to secondary hard drive

You'll have to edit apache2.conf and 000-default.conf to change the document root of apache.
The Apache server is installed on /var/www/html.This is the default root directory of apache.
Either change the root directory of Apache or move the project to /var/www/html.

To change Apache's root directory, run:
 cd /etc/apache2/sites-available

Then open the 000-default.conf file using the command:
 nano 000-default.conf

Edit the DocumentRoot option:
 DocumentRoot /path/to/my/project

Then restart the apache server:
 sudo service apache2 restart

If you get Forbidden You don't have permission to access / on this server after changing the root of apache then do follow these steps

Find the apache2.conf located in /etc/apache2 and open it using:
 nano apache2.conf

Use Ctrl+W and search for Directory (It should be in line 153)

It should look like this
 <Directory />
     Options Indexes FollowSymLinks
     AllowOverride All
     Require all denied
 </Directory>

Change it to
 <Directory />
     Options Indexes FollowSymLinks Includes ExecCGI
     AllowOverride All
     Require all granted
 </Directory>

Restart apache
 sudo service apache2 restart

I made a script that changes apache root in a single command. You can find it on my github.


Ubuntu Server 18.04.2 for Raspberry Pi 3+ login loop

Try rebooting the PI. I had the same issue with a fresh install of Ubuntu Server 18.04 on a PI 4.  I was connecting over SSH.  It told me the password was expired and requested a new one.  It allowed me to change it, but then disconnected the session.  I could reconnect only to have it tell me my new password was expired and request I set a new one (and so on and so forth).  After rebooting the PI I was able to login normally using the newest password I had set.


12.10 - Can't connect to internet in software updater

This generally means that there is no PPA for the current version of Ubuntu you are running (quantal).  if you go to http://ppa.launchpad.net/eugenesan/java/ubuntu/dists/ you will see PPAs for previous releases.

lucid/  19-Jan-2012 09:12   -

[DIR]   maverick/   19-Jan-2012 09:12   -
[DIR]   natty/  19-Jan-2012 09:12   -
[DIR]   oneiric/    18-Jan-2012 14:22   -
[DIR]   precise/    19-Jan-2012 09:12

So you need to wait until a quantal PPA is added.


Copy file to dir using wildcards or regular expression in destination?

The error is because the shell try to expand * glob character before executing the command, and the destination do not exist yet. One possibility to overcome this would be

cp debian.master/abi/2.6.38*/amd64/generic "$(eval echo debian.master/abi/2.6.38*/amd64)"/core2

More simply you can do:

( cd debian.master/abi/2.6.38*/amd64/; cp generic core2 )

Or also

dir=debian.master/abi/2.6.38*/amd64/
cp "$dir"/generic "$dir"/core2


How can I be careful installing node.js via apt?

Short Answer

Just use the stable one from the repositories , it should be fine.

Long answer

The latest stable should hopefully end up in the repositories, as long as they are updated regularly.

The latest version currently is v0.10.25, which was released a week ago*, according to the nodejs website. If nodejs is installed, dpkg can list the current version:

:~$ dpkg -l nodejs*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version      Architecture Description
+++-==============-============-============-=================================
ii  nodejs         0.10.15~dfsg i386         evented I/O for V8 javascript
ii  nodejs-dbg     0.10.15~dfsg i386         evented I/O for V8 javascript (de
ii  nodejs-dev     0.10.15~dfsg i386         evented I/O for V8 javascript (de
ii  nodejs-legacy  0.10.15~dfsg all          evented I/O for V8 javascript (le
:~$

So in Ubuntu 13.10, the latest version seems to be 0.10.15. According to the nodejs Changlog, this is the version from 2013.07.25 - the 25th July 2013, so it is half a year old*.

The EtherPad on GitHub shows that version 1.3, the latest version*, was released at the end of October 2013, so as this is only 3 months newer than the version of nodejs in the repositories, there us probably no need to bother.

Of course, if you wanted, you could download the latest stable version from here:http://nodejs.org/download/

Though it would be easier to wait for the Ubuntu repositories to catch up Even though that can take a while...

*at the time of writing


How to install RT2870/RT3070 Wireless Driver?

I have a device that uses the same driver, just labelled ralink USB Wifi Dongle.  This is what I did to get mine to work:

UPDATE:  You may have to download kernel headers, if you don't have them already:

sudo apt-get install linux-headers-$(uname -r)

Plug the dongle in, and run the following lines in a terminal:

git clone https://github.com/porjo/mt7601.git
cd mt7601/src
make
sudo make install
sudo mkdir -p /etc/Wireless/RT2870STA/
sudo cp RT2870STA.dat /etc/Wireless/RT2870STA/
sudo modprobe mt7601Usta

Afterwards, it picks up in the GUI network tool.  A reboot may be required.

Hope that helps.


Which Desktop Environment has (or can have) global menus (apart from Unity)?

What I’ve read:

Super Wingpanel (not a DE) can can do that task
gnome-globalmenu does it for Gnome2 and now also Gnome3

I have no idea yet if they can be configured to the limitations mentioned in the question (maximized windows, no timeout).


Disable Increasing Speaker Volume (for Child)

Type in Terminal :-  sudo alsamixer
and you can customize the volume.


Network manager dies if my router drops the internet connection

The latest version of network manager fixes the issue


What is Canonical's LTS support policy for EOL software?

PHP is in the main repository.

$ apt-cache policy php5
php5:
  Installed: (none)
  Candidate: 5.3.10-1ubuntu3.6
  Version table:
     5.3.10-1ubuntu3.6 0
        500 http://nl.archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ precise-security/main amd64 Packages
     5.3.10-1ubuntu3 0
        500 http://nl.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

and supported for 5 years:

$ apt-cache show php5 | grep ^Supported
Supported: 5y

Canonical's definition for software in this repository is:

  Main

  The main component contains applications that are free software, can
  be freely redistributed and are fully supported by the Ubuntu team.
  This includes the most popular and most reliable open-source
  applications available, many of which are included by default when you
  install Ubuntu. Software in main includes a hand-selected list of
  applications that the Ubuntu developers, community and users feel are
  most important, and that the Ubuntu security and distribution team are
  willing to support. When you install software from the main component,
  you are assured that the software will come with security updates and
  that commercial technical support is available from Canonical.

So, yes, the policy is to provide security updates to PHP for five years, independently of what PHP is doing. This is not unique to Canonical, but also Red Hat, Debian and other distributions backport security patches for newer versions.

I don't think that point releases of Ubuntu LTS will upgrade to PHP 5.4 - it may be available as a separate package though. See also What are point releases in LTS versions?


Failed 18.04.1 installation - The 'grub-efi-amd64-signed' package failed to install

The point is that you need to have EFI System Partition. So create one with 512MB.
For detailed installation instructions check:
Ubuntu 18.04 LTS Minimal Install Guide


Why is running localedef not creating my new locale in /etc/locale.gen?

What you seem to have missed is adding you custom locale to

/usr/local/share/i18n/SUPPORTED

with the line

en_US@XX UTF-8

Then a simple sudo locale-gen should do what you want.


Canoscan Lide 210 scans but I don't get an image just blank gray image

I just found the answer to my own question. I did an internet search on the Canon Lide 210 and blank gray image and I found this. Someone stated that on the underside of the machine is on the outside is a simple mechanical lock. Just slide it to unlock and it will stop putting out blank gray scans and start scanning. Now for how well it scans I'm not sure I just got it working. What a relief. Oh well at least it is solved. I've had time to try it out and it works great. Problem solved.


How can I access Facebook and other forbidden websites in China?

Configuring a VPN is pretty simple. Open up the Network Connections dialogue and hit the VPN tab, as below:

That leaves two issues:

You need a VPN to connect to. These are widely available but cost money. Note that some if not all of these might be blocked by China (for obvious reasons). You might need to rent your own server (eg from a company like Linode) and install your own VPN server. You could just use a Socks proxy over SSH if that's what you end up doing - Much easier and should work for most things.
Is this legal in China? I personally don't care how many of China's laws we break on Ask Ubuntu because we're not in China. I think their firewall is a horrible incursion on people's natural right to free uncensored information and that China use it to suppress their citizens. In short, I think this question is fine on here.

But do be conscious that if you're breaking laws in China, and they find out (which they might), they might take legal action. And given China's record for open and fair judicial process, this could result in a 10 minute hearing followed by 10 years of wondering what you'd be doing if you didn't need to check Facebook.

I'm not dropping the super-downer to put you off - just be careful.


None of these are commands that are correctly used.

You are missing spaces in this one:

sudo chown -Rv $USER ~/.tor-browser

Here USERNAME is not a valid word. Plus what is the < BR >!?

sudo chown -R $USER /usr/bin/tor-browser <BR>

Again missing a space but USERNAME is not a correct word. :

sudo chown -R $USER /usr/bin/tor-browser

These 3 should be the valid method for each of the commands. Options (probably mandatory) go in front of the $USER (that is substituted for your current user).


How to browse the web safely with Mozilla Firefox?

Firefox 3 or later contains built-in Phishing and Malware Protection to help keep you safe online. These features will warn you when a page you visit has been reported as a Web Forgery of a legitimate site (sometimes called “phishing” pages) or as an Attack Site designed to harm your computer (otherwise known as malware).

SOURCE

NOTE:
You can also install the following Add-ons for Firefox, for secure browsing.With flash and scripting off, all that is left in browser is html and images and these are not too dangerous.

Flashblock  NoScript  Adblock Plus


I have struggled with this exact same problem and every search comes up with several others experiencing the same issue with no resolution.

FINALLY, here is what solved it for me:

ip addr flush dev <your_adapter_id>

for me it was

ip addr flush dev enp0s4

...then reboot.

sudo shutdown -r

This kills the secondary IP.


Why do I get an error when trying to use U1db with the Ubuntu SDK?

You can safely ignore that error message -- annoying I know, but the component works even though QtCreator complains (and you don't get autocomplete).
You can find more U1db examples here: http://bazaar.launchpad.net/~uonedb-qt/u1db-qt/trunk/files/head:/examples/


Which Version ( ISO ) to Install with VMware Fusion?

Install any of the currently supported versions. They all should work.

There are four supported versions currently: 12.04, 14.04, 15.10 and 16.04.

12.04, 14.04 and 16.04 are all LTS (long-term support) releases, which have pretty self-explanatory descriptions.

12.04 will be supported until mid-2017.
14.04 will be supported until mid-2019.
16.04 will be supported until mid-2021.

15.10 is not an LTS release. Normal releases are supported for about 9 months. 15.10 was released October 2015. If you install 15.10, you'll have to upgrade to 16.04 once the end-of-life date comes.

LTS releases only let you upgrade to a new version of Ubuntu (by default) if the new version is another LTS. Even then, it waits until the LTS has reached x.04.1 before prompting you to upgrade. If you need stability, go with LTS.

Non-LTS releases prompt you to upgrade on each new release, which is every 6 months. These are good for getting new features, drivers, kernels and programs, but are not the nest option for stability. If you upgrade from a non-LTS release to an LTS release, you will still be prompted every 6 months to upgrade. Use a non-LTS if you like new features and are more into experimenting.


Is there a safe way to reinstall via the package manager?

A good way to deal with file corruption is to use `debsums' (see these instructions, and also this great answer), though they're starting with a non-booting system) which will discover which files are corrupted; then you can reinstall just those packages.

Your reinstall command is safe, but it's not guaranteed to fix everything that might have been caused by a hardware error.

You might also like to force a fsck or run a badblocks scan.  You can do both of those from inside the disk utility.


Installation of MongoDB via SoftwareCenter failed

What kind of file system are using on /data/.. ? I imagine it could be a problem if you are using NTFS on that mount point.

Another problem could be the version of BOOST you have installed. I am not sure if MongoDB will work with BOOST 1.46. In the build description for Windows at least, they state:

  We have successfully compiled version 1.42 – you might want to try that version or higher, but not 1.45 or later. 1.45 changed the interface to the boost::filesystem library and we've yet to catch up. See additional notes section at end of this page too.


Wireless USB Keyboard and Mouse not Detected Ubuntu 12.04

try to upgrade the kernel.. that might work.. do it with "sudo apt-get install linux-generic-lts-trusty" I know that you're unable to type with your keyboard but you can copy and paste this command. This worked well to me for recognizing a usb webcam and my touch screen. It's about the drivers.


Is it advisable to become root in Ubuntu to work with other users' files?

You may find this helpful. Consider placing shared files in common directories with appropriate permissions so that multiple users can work on them.


How to quarantine or delete infected files with ClamAV?

You can use clamscan with the option --remove to automatically remove all infected file in the scanned folder. WARNING: Files are gone.

clamscan -r --remove /home/USER

Another possibility is to move the infected files to another folder with the option --move=FOLDER, so you can later check which files of them maybe not infected or a virus.

clamscan -r --move=/home/USER/VIRUS /home/USER

See: How do I scan for viruses with ClamAV?


How to setup wireless printing from a printer connected via usb on Ubuntu Server 12.10?

Yes, there are (at least) two possible ways.

The easiest is to simply share your printer via CUPS. To do this, open the printer dialogue (system menu -> printers) and right click on the printer. Make sure that the checkbox "Share this printer" is checked. Now you are done on your Linux box.

On how to set up printing to IPP using Windows 7, read this guide:
https://superuser.com/questions/300986/ipp-printing-from-windows-7-ultimate

Use the generic postscript driver for the printer in Windows, conversion from postscript to the printers native format is done by the printer driver installed on ubuntu.

The second, much more complicated way is to set up SAMBA sharing.


As far as I know (and I've researched this for somebody else before), there are no desktop apps that can open Visio VSDs on Linux. Even Visio under Wine seems to struggle.

However, there is Zamzar. It's a webservice that converts lots of documents. You just have to give them the file, tell them what you want in return and give them an email address. Might sound fishy but they're under UK privacy law, which despite our government, is actually pretty strict. Their privacy policy explicitly says they don't sell on your details or documents.


At first ensure that you have enabled all repositories in your system:

sudo add-apt-repository main
sudo add-apt-repository universe
sudo add-apt-repository multiverse
sudo apt-get update

You do not need to compile reaver by yourself since it is packaged with version 1.4-2build1. Use:

sudo apt-get install reaver

If you still need to compile it (with custom ./configure options or just for new experience) - you should enable Source code repositories in Software & Updates (software-properties-gtk) and install its build-dependencies with

sudo apt-get build-dep reaver

and then continue with ./configure.


viewing of files contents using command line in ubuntu

You don't need grep at all - you can us the bash shell's built-in pattern matching (globbing) feature. For example (assuming "numeric" in this context means a decimal digit):

ls [0-9]*[^0-9A-Za-z]

or

ls [[:digit:]]*[^[:alnum:]]

See for example

Bash Reference Manual: Pattern Matching

Note that if you want to view the files' contents as per your title, you will need something like cat (or perhaps head) in place of ls.


Unmet dependencies when installing Clang++

The problem is that there is no package Clang++ or even clang++, so apt is treating the given name as a regular expression and trying to install every matching package - many of which conflict with each other:

$ sudo apt-get install --dry-run Clang++
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'clang-modernize-5.0' for regex 'Clang+'
Note, selecting 'libclang-3.6-dev' for regex 'Clang+'
.
.
.
Note, selecting 'python-clang-3.3' for regex 'clang+'
Note, selecting 'python-clang-3.4' for regex 'clang+'
Note, selecting 'python-clang-3.5' for regex 'clang+'
Note, selecting 'python-clang-3.6' for regex 'clang+'
Note, selecting 'python-clang-3.7' for regex 'clang+'
Note, selecting 'python-clang-3.8' for regex 'clang+'
Note, selecting 'python-clang-3.9' for regex 'clang+'
.
.
.

In fact, unlike gcc/g++, clang provides both C and C++ compilers as a single package - you can install a specific version such as clang-3.5 or simply install the highest-priority version for your system via the clang dependency package:

sudo apt install clang

See for example How to install clang++?


Problem accessing Windows Share from Ubuntu using Samba

Ok I finally fixed it the usb port on which the external hard drive was plugged somehow blocked the share when I was trying to access it from Linux even though it caused no problem when I was trying to access it from Windows.

Anyway I switched ports and everything is fine now.


How to copy a subset of files from a certain folder

You could for instance use the find command with the -exec option. You'd probably use some syntax like the following (has to be run in dirB, and be aware that it's recursive):

find ./ -type f -exec cp '../dirA/{}' ./ \;

The -type f tells find to only take into account regular files, the -exec says: run the following command on every file. The \; at the end terminates the command to be run. The {} is a placeholder that is replaced by the actual filename by find.
Check out the man page of find for details and other usage examples.

Here's what happens on my PC:

desktop:~$ mkdir dirA
desktop:~$ mkdir dirB
desktop:~$ cd dirA
desktop:~/dirA$ touch foo bar this
desktop:~/dirA$ cd ..
desktop:~$ cd dirB
desktop:~/dirB$ touch bar this
desktop:~/dirB$ find ./ -type f -exec cp -v '../dirA/{}' ./ \;

»../dirA/./this“ -> »./this“
»../dirA/./bar“ -> »./bar“


One solution which doesn't require root privileges is to create a file with the size of the partition, call mkfs on that file, then copy the file into place.

truncate -s 64512k part1.vfat
/sbin/mkfs.vfat part1.vfat
dd if=part1.vfat of=mountedImage.img bs=1k skip=2048

Alternatively, with root privileges, you can set up a loop device that gives you access to the image as a device. Since you want to access only part of the image, you'll have to indicate that explicitly.

sudo losetup -o 2048k --sizelimit 64512k đev/loop0 mountedImage.img
sudo mkfs.vfat /dev/loop0
sudo losetup -d /dev/loop0

To work with more comfortable tools, you need root privileges and a reboot. The loop module can provide access to partitions, but this is disabled by default. To enable this access, edit /etc/default/grub and change the line GRUB_CMDLINE_LINUX="" to

GRUB_CMDLINE_LINUX="loop.max_part=15"

If there were other options there already, leave them, of course; they need to be separated by spaces and the whole option string must be inside double quotes, e.g. GRUB_CMDLINE_LINUX="option=value anotheroption loop.max_part=15".

Now, after you've partitioned the disk image, run

sudo losetup /dev/loop0 mountedImage.img
sudo mkfs.vfat /dev/loop0p1

Run losetup -d /dev/loop0 when you've finished working with that image.


How to completely disable updates of all kinds, and not ever see prompts to update?

Go to System Settings > Software & Updates or type software-properties-gtk in a terminal, and select Updates tab. That window it should look like in next image if you want to not recieve any kind of updates:

Or, from terminal, comment (with # at the start of every line) all the content of /etc/apt/sources.list file:

sudo nano /etc/apt/sources.list

To automatically comment everything in /etc/apt/sources.list file, use:

cd /etc/apt && sudo cp sources.list sources.list.bak && sudo sed -i -e 's/^/#/g' sources.list

This command create also a backup for /etc/apt/sources.list file and can be very useful when you have to configure many computers.


The problem is that, by default, PHP 7 does not supports short open tags <?.

It is described in the article PHP tags from php.net.

You need to use the full open tag <?php. Or, if you have PHP programs which are written for previous versions of PHP, you can change this rule in these ways:

you can add next directive into your-apache2-virtualhost.conf (or .htaccess) file:

php_flag short_open_tag on

into the file /etc/php/7.x/apache2/php.ini you can set:

short_open_tag = on

Don't forget to restart Apache2:

sudo systemctl restart apache2.service


If you just want a live session or just want to wipe Windows ME to install Ubuntu, there is nothing related to the current operating system. Just make sure you selected "Try Ubuntu without installing" when booting into your copy to get live session. Or just simply select "Renove all files and install Ubuntu" when installing to wipe out Windows ME and install Ubuntu.

However, if you want to dual-boot it might be difficult. Wubi doesn't support Windows ME now, and it makes sense for your copy not to support it. Windows ME is 13 years old now.


Exit code 13 pretty much always means you have a mix of 32 and 64 bit code.

You are using a 64 bit Eclipse (the launcher has x86_64 in the name) so you must be using a 32 bit Java.

You must use a 32 bit Eclipse and 32 bit Java or 64 bit Eclipse and 64 bit Java.


Pitivi has put a lot of work to make a decent video editor that has power and simplicity for the needs of you and me ;)

Check it here: http://www.pitivi.org

The ppa is here: ppa:pitivi/stable

If you find that this doesn't match your needs say so and we will find something else! Gl!


How can I delay dropbox from starting, but not disable it?

First, disable Dropbox from starting on login.
Open up the DropBox preferences and uncheck Start Dropbox on system startup:

Now we will manually add Dropbox to the list of applications that run on login.
 Open up System ➜ Preferences ➜ Startup Applications and click on Add to add a new entry.

Use Dropbox for the name and bash -c "sleep 10m && dropbox start -i" for the command, and then click Add to save it.

That's it, now Dropbox won't start until 10 minutes after you have logged in.


i have changed the hard disk with another one with windows on it then i get in the bios by keeping pressed shift and pressing one time the shutdown button at the same time , and then i was able to get in bios.


The German keyboard layout includes "latin(type4)", and the 9 key definition comes from there. So open the /usr/share/X11/xkb/symbols/latin file for editing and find the <AE09> definition in the "type4" section.


This is normal behavior for any new kernel release and existing kernel objects / modules will not work until they are updated and made compatible with the kernel you are running.

However in your case, it appears like there is a non-official patch available which I have tried and it worked for me but I do not recommend it hence for not posting the link but if you still want to go ahead with it, please respond to this post and request it.


Apache2 not starting on Ubuntu Server 17.04

Solution by working around with support by @Nadav Tasher:

Nginx won't work properly! Two services (nginx-apache2) won't work same timely! Running Apache2 has fixed the issue permanently!


Ubuntu 20.04 doesn't boot up - num lock blinking

Yeah, it was because of full disk usage. If you have these issues too, here's how to fix it:

Boot into recovery mode.
Choose root console.
Use the command line to find and delete large files you don't need.
Reboot and check if it helped.


dd allows you to write data directly to a block device, but doing so to a physical device requires root.

sudo dd if=/dev/zero of=/dev/sdX

Change the X to whatever drive you wish to wipe, and use either sd or hd, depending on your disk type.

This doesn't really protect your data though. Anything in memory could still be read (in theory) by your employeer.

I can't think of a use case where destroying your data would be that critical. With that said, I've turned in plenty of laptops where my goal was to destroy my PERSONAL files like my KeepassX databases, and for those cases, I'd suggest focusing only on your personal data and using GNU Wipe (sudo apt-get install wipe -y). This will let you overwrite your file content and then renaming them so they shouldn't leak data just by name.

But ultimately, any adversary that has physical access to a machine that's powered on should be assume to be able to get some information from that machine. A more secure method would be booting from a LiveCD so that none of your data is loaded as the machine is powered on.

Additionally, make sure to encrypt your laptop (including swap, which might leak information unencrypted) at your next job.

EDIT:
Corrected a typo that specified sda rather than sdX.


Where and how do I find the *desktop*.iso file needed to install Universal USB Installer? I need it to install Ubuntu

Navigate to this webpage: http://releases.ubuntu.com/precise/
Choose the right architecture (x86 or amd64) for your machine from the Desktop CD section
Download this file
Use Universal USB Installer to write it to a USB

See this link for more detailed instructions: How do I install Ubuntu?


HDMI stops working when DisplayPort is unplugged

It may so happen that, the display ports listed in xrandr may be mislabelled because of manufacturer's error or whatever.

So, it will prove useful to experiment by forcing the outputs through the various ports listed by xrandr. One of them would give the output on the port that you would have physically connected the second display to.

So if you have HDMI-1 and DP-2 as the options available, you can try forcing output through both of them(You may want to try with all other options listed in your xrandr output, till you get an output).

xrandr --addmode HDMI-1 1680x1050
xrandr --output HDMI-1 --mode 1680x1050

and

xrandr --addmode DP-2 1680x1050
xrandr --output DP-2 --mode 1680x1050

You may have to play with the resolution to get a properly sized output. As pointed out in the comments, the second set of commands, modified with the correct resolution, that worked for the OP is with 1920x1080 resolution.

The following answer may be referred for more detailed explaination:
https://askubuntu.com/a/968522/574724

These questions also might help:

xrandr not showing my VGA port, instead it lists DP1
Can I force VGA signal output even when xrandr shows 'disconnected'?


With the price of USB flash drives what it is, compared with the value of whatever you're likely to store on it, the best thing I can suggest for a flash drive with bad blocks is to toss it in the trash (erase with a hammer first, if you're concerned about data that might be recoverable from the drive) and buy a new one.


You can access the address file for each device on the /sys virtual filesystem. The MAC address should be in /sys/class/net/<device-name>/address:

$ cat /sys/class/net/enp1s0/address
34:17:eb:5d:88:7c

For all devices:

$ cat /sys/class/net/*/address
34:17:eb:5d:88:7c
00:00:00:00:00:00
64:5a:04:69:50:45


Wireless network says no firmware and so I can't connect to the Internet

You didn't specify what device it is for, but generally speaking, you should try these things first:

Open Additional Drivers as described here: How do I install additional drivers?
Make sure you've enabled multiverse repository (see How do I enable the "multiverse" repository?) and install these two packages: linux-firmware  and linux-firmware-nonfree  with your favourite package manager.

It should provide the firmware files you need.

The drivers and/or firmware aren't shipped with Ubuntu by default due to licensing issues.


How do I turn off the laptop screen while using an external monitor?

Find the Name of displays by run xrandr in terminal(your laptop screen is something like LVDS1, and your external monitor is some thing like VGA).

# turn off laptop screen
xrandr --output LVDS1 --off

If you need to turn on the laptop screen::

# laptop screen on
xrandr --output LVDS --mode 1280x800

If you want to turn off external screen::

xrandr --output VGA --off


How to get the process id which uses the administrative directory(/var/lib/dpkg)?

You can use "fuser" to get the pid of the pocess to kill:

sudo fuser /var/lib/dpkg/lock

you can use switch "-k" with fuser to kill the processes hanging on /var/lib/dpkg/lock


Partitioning Windows 7 so I can use ubuntu

If the latency is an effect of the Windows software, then it's possible that he's correct. I would follow the partitioning instructions here: Resize Windows Partitions

There are some decisions to be made as to which boot loader to use (Ubuntu's boot menu or use Windows boot menu).  After the partitions are resized, I would follow the rest of the instructions in this walk-thru: Ubuntu dual-install from bootable CD-drive

Which boot menu?

As far as I can tell, there is no general agreement on this answer.  But one concern that I thought was important to note was that certain Windows antivirus applications might cause problems if they notice changes to the Master Boot Record.  If that's a concern for you, I heard that EasyBCD is the way to go. Even so, I personally use Ubuntu's boot manager.

Another concern from a different website is that if you update or upgrade your Windows 7, it will rewrite your Master Boot Record anyway (deleting your entry if you use Ubuntu's loader).  You can read more for that here.


WIFI hotspot only running at 144mbps@5GHz but should be much faster Alfa Network AWUS1900

Ok, it's me again.
I couldn't do it with Linux (Ubuntu & Kali) so I thought about something else.
Somewhere I read that the windows hotspot limitations came with an update some time ago. These limitations are the reason why the hotspot in default starts as 2.4GHZ, or if maybe in 5.0GHz, then limited to 144Mbps - 173Mbps max. It's not possible to create a 5GHz full-speed hotspot.
So what I did was:

grabbed Windows 10 - version 1903 (that is the latest working I heard!!)

installed it on a VM with VMware Workstation (3GB RAM, 2 Cores, USB3.0, minimalistic)

keep internet disabled until the last step!!

disabled everything that's unnecessary

set network to bridged --> BUT DID NOT TURN IT ON!!!

disabled windows update (via gpedit and services)

disabled automatic driver installation

decrapified windows via "Windows 10 Decrapifier"

installed windows 10 driver for AWUS1900 / RTL8814AU from the dvd

CREATED SNAPSHOT OF THE VM (saved checkpoint)

enable ethernet

connect AWUS1900 via VM hotplug

connect to any (at best 5GHz) wifi (create hotspot with smartphone if necessary) --> other wise it will only create a 2.4GHz wifi... if already connected to another wifi it will create a 5GHz hotspot

don't enable hotspot yet

go to hotspot settings

set up hotspot with SSID and password

enable hotspot

disconnect wifi (recommended because it's not needed anymore)

--> check hotspot with other devices, it will run with full-speed (in my case 867mbps)
(if not try again, it can be a pain in the ass, also check out nearby wifi frequencies and check if something is on the same channel as your hotspot, this can cause it to limit speed [I had to switch my fritzbox-channel from 60 to 40 because they were both on 60]!)

minimize the VM, so it will run in background
connect Oculus Quest with the wifi-hotspot (it shows 867mbps, full speed)
launch VirtualDesktop on PC and Quest

--> Through bridged connection the Quest is in the same LAN as the PC and has direct access to VirtualDesktop with minimal latency and maximum bandwidth. It works just as good or even better than via a wifi-router. I just played some shooters in VR via VD and it works perfectly. Super low latency!
CHECK PICTURES/SCREENSHOTS:
Wifi Analyzer - Android
inside VM
inside VM
View from other windows PCs


Openconnect in Juniper mode suddenly fails with "Failed to obtain WebVPN cookie"

The solution turned out to be a manual upgrade of Openconnect.

Via apt-get install --upgrade-only openconnect, I confirmed I was already on the latest version (7.06-2build2)

I downloaded the latest version (7.08) and built it manually.  Since the vpnc-scripts package puts the vpnc-script in a different location than the default, I needed to give that info configure.  I also didn't care about missing DTLS support, so told it to just use my current version of openssl:

./configure --with-vpnc-script=/usr/share/vpnc-scripts/vpnc-script --without-openssl-version-check

as well as add a few missing packages needed for the build - in my case libxml2, libxml2-dev, and pkg-config.

Finally, since the Xenial packaged used GnuTLS, but my build was using OpenSSL, it couldn't read the cert file as a .der and got a Failed to open CA file.  This was fixed by converting it to a .pem (the OpenSSL default):

openssl x509 -in /etc/ssl/certs/vpn1.company.com.der -inform der
             -out /etc/ssl/certs/vpn1.company.com.pem -outform pem

I suspect there had been a change on the VPN server side that began sending a "Pre Sign-in Message" which is now supported in 7.08.


If your multi-function device is connected by USB to your computer, then it does not have an IP address. You should try to configure in another way.

If your multi-function device has an Ethernet port (for network cable), and is connected to your local network (to the router), then it has an IP address. You can print the settings page of the device in order to find the IP address.


Try run:

sudo apt install python3-tk

It will install tkinter module for python 3.


How to dual boot Windows and Ubuntu on 2 hard drives

In general you can just follow the instructions Hany gave you, but since you want to install them on two discs you should check the something else option in the installation process. Now you should make all partitions needed. In this article they describe the partitions, they choose to make a separate /home partition, this is sometimes useful because all your application settings en personal documents are saved there, and when you reinstall these remain untouched. but you can also just make a /boot, a swap and a / partition (just fill all the left over space with /)


You are probably looking for something like lxml.

Please have a look at the lxml webpage

You can install it in ubuntu with

sudo apt-get install python-lxml


Expanding ext4 and shrinking NTFS partitions on the local drive

Use Gparted

First of all unmount the required partitions.
Next using choose the required NTFS and right click and choose Resize/Move.
Shrink the partition as per your needs.
Repeat the steps with the ext4 partition.


How to format Read-only filesystem drive?

This is a nice tutorial walk through of how to format a USB drive:

https://itsfoss.com/how-to-format-a-sd-card-or-usb-drive-in-ubuntu-12-10/

In short:

sudo apt-get install gparted
sudo gparted
Select your usb drive in the top right of gparted
Make sure to unmount the drive (this is key), right click on the drive and select unmount
Now to can format it, right click on the drive and pick your file system :)


How to change wrong icon from Unity launcher and Dash?

Usually, when the Icon= line is changed in a .desktop file, it should be visible in the launcher after log out/log in. When an application is re- installed its icon should change as well, there is no "Unity memory" as you mention it.
Priority of .desktop files
Another thing is that a local version of a .desktop file (in ~/.local/share/applications) has priority over the global one in /usr/share/applications. Since you mentioned having an (old) local copy of your .desktop file (in a comment), your newly defined icon in the global .desktop file only takes effect after you removed the local .desktop file.


Problem in booting from new installation of Ubuntu 14.04 to a new ssd Hard disk

First, try booting your installation medium in "try before installing" mode, open a Terminal window, and type:

sudo blkid

This command will produce information on your disk partitions, something like this:

/dev/sda2: LABEL="SSD_ESP" UUID="E231-242F" TYPE="vfat"
/dev/sda3: UUID="5028fa50-0079-4c40-b240-abfaf28693ea" TYPE="ext4"
/dev/sda4: UUID="65e70569-536a-4b50-b7c7-9267359447e8" TYPE="reiserfs"

Scan this output for the UUID value (the long hexadecimal number) from the "no such device" error in your first screen shot. If you can find that specific number, then that suggests that for some reason, GRUB can't find your SSD, although Ubuntu can. This can happen when a SATA device is plugged into a port that's not accessible to the firmware, but that is accessible to Linux. In such a case, moving the disk to another SATA port on the motherboard may help. Consult your manual for information about which physical ports are controlled by which disk controller chipsets. If one of your other disks has no bootable OS, you might be able to simply swap cables.

If you don't see the UUID from the message in your blkid output, then that suggests that your GRUB configuration is corrupt. This might happen if you're launching an old GRUB from a previous installation. It could also happen if the GRUB setup scripts have a bug. (It looks like your EFI System Partition is on another physical disk than your Ubuntu boot partition, which is unusual enough that it could be triggering a bug that few people encounter.) Two possible solutions/workarounds spring to mind:

In the Ubuntu live disk, run Boot Repair. This tool can fix many GRUB problems, but it's not guaranteed to succeed, particularly if the problem is a GRUB bug.
Download the USB flash drive or CD-R version of my rEFInd boot manager, prepare a medium with it, and boot it. (You may need to disable Secure Boot, if you haven't done so already.) This should give you options to boot Ubuntu and whatever other OS(es) are on your disk. If you can boot all your OSes, boot into Ubuntu and install the rEFInd PPA or Debian package. This should set up rEFInd as your main boot manager, bypassing GRUB.


"Docky needs composition enabled" message even after I enabled that, in Xubuntu

enabling docky effects in xfce
By default, Docky should work with the built-in XFCE/Xubuntu compositor.
In 12.04 the compositor can be checked (if it is not already) via the window-manager tweaks

The image above shows Docky does not have the 3D effects, but by checking the options you'll have the 3D effects as per the next image:

If, for whatever reason the inbuilt compositor does not work for you, you'll need another compositor to help out Docky.
alternative method for both XFCE/LXDE
A good lightweight compositor is xcompmgr
xcompmgr

As the image above shows, the inbuilt compositor is not running.  xcompmgr is running, which gives Docky the 3D effects you require.
Use session and startup to run xcompmgr when you login.


How do I remove Wine program entries from the menu?

It should be enough to remove the local wine folder ~/.local/share/applications/wine.


In case our mp3 files are not already tagged with lyrics (which is the usual case unfortunately) there are several other approaches to have access to lyrics while listening to mp3 music:

How do I install third-party rhythmbox plugins?
By installing a third party plugin for rhythmbox you will be able to have online access to lyrics from sources other than with the default plugin shipped with Rhythmbox.
Need a MP3 ID3 tagger, and cover fetcher
Application to automatically search lyrics and store them in ID3-tags
Some ID3 tag editors are able to also store lyrics in the tags. This - to my knowledge - can not be done automatically.
What media (music and video) players are there?
Choose a media player capable of editing tags to also store lyrics. We have good experience with guayadeque , a media player that comes with a tag and lyrics editor. This can be set up to search from several or custom lyrics sources from the Internet.


Setting Global Variables for Mysql On Ubuntu 17

Firstly, it looks like you've got some copy-paste issues going on. The mysql> is the prompt from the console client, so this should never be in any configuration file.

Secondly, when setting variables in the configuration file, they just fall under the respective [section] headers one per line and key values are separated by an equals = sign.

So in /etc/mysql/mysql.conf.d/mysqld.cnf anywhere under [mysqld] add:

sql_mode = STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION


Ubuntu update failing on my brand new BQ aquaris E4.5 Ubuntu Edition Phone

Contact the support department from BQ themselves here as you need specialised tools to flash your phone from a computer (this can be a Windows computer, no Ubuntu computer necessary).

BQ will help you for free if your phone is still under warranty.  If your phone is out of warranty, come back here and leave a comment below this post.


Upgrade SVN version after Ubuntu upgrade

find / -type f -name '.svn' will list all the path containing this directory which is present in each SVN working copy you have on your system.

Change into the top directory found containing a .svn one. There is the top of your working copy where you can run svn upgrade.

As you certainly checked out the SVN using your own user account (svn co <repository location>, you don't need sudo. You don't need to run the svn commands with sudo or all the files checked out will be owned by root. So all editing would have to be done using sudo too.


How to download big sites with several interrupted wget:s?

I think you are actually asking how to resume interrupted downloads of big files. In order for that to work, the server must specify in the header how large the file is. Otherwise most tools, it not all, will never resume a download and always start from the beginning, until they no longer receive any bits from the server. You can check manually if the content-length attribute is specified in a header by running curl -I <url.

For example, we can check the header we get for the askubuntu page logo:

$ curl -I https://cdn.sstatic.net/Sites/askubuntu/img/logo.svg

HTTP/2 200
cache-control: max-age=604800
content-type: image/svg+xml
last-modified: Wed, 22 Jan 2020 23:01:03 GMT
accept-ranges: bytes
date: Thu, 23 Jan 2020 14:30:06 GMT
via: 1.1 varnish
age: 0
x-served-by: cache-mxp19838-MXP
x-cache: MISS
x-cache-hits: 0
x-timer: S1579789807.662934,VS0,VE117
vary: Accept-Encoding
content-length: 11748

At the very bottom you can see content-length: 11748, which would enable wget to resume the download if interrupted.

Also, you can use ariac instead of wget, which in my opinion handles interrupted downloads better.


In "File - Preferences" of the CopyQ application, enable "Hide main window" on the "Layout" tab. This will cause CopyQ to be removed from the Alt+Tab pop up whenever the window is closed.


Directory Stack in Bash

There is something know as directory stack or DIRSTACK in bash. Stack is a basic data structure in computer science, where you can store elements on top of each other(like a book stack), but access only most recent one (top).

Here's a small demo - each time i push something on to directory stack, my current working directory is set to that item; every time i pop - we delete the top (left-most ) item from stack, and return to next available item:

$>  # pushd navigates to and stores the directory given
$> pwd
/home/xieerqi
$> pushd bin
~/bin ~
$> pushd /etc
/etc ~/bin ~
$> # popd deletes leftmost item, returns to next directory on left$> pwd
/etc
$> popd
~/bin ~
$> pwd
/home/xieerqi/bin
$>

The most recent item is always stored as the top of the stack, even when you use cd

$> dirs
/ /etc ~
$> cd /var
$> dirs
/var /etc ~
$>

The dirs command allows us to retrieve an nth element from the stack. Using that output as argument to cd we can navigate to any directory that is on the stack, without affecting the stack itself. Notice bellow how /etc/ and ~ (stack elements 1 and 2) stay the same, even though I change my current working directory (and the top element as well)

$> dirs
/var /etc ~
$> dirs +1
/etc
$> cd $(dirs +1)
$> pwd
/etc
$> dirs
/etc /etc ~

Using DIRSTACK behavior to simulate web browser behavior

You know how in a web browser if you jump from url A to url B and url C, you can kind of go back and forth between them using back and front arrow keys ?

Well, we can do the same in bash with these two functions:

cd()
{
  if [ $# -eq 0   ]; then
       pushd "$HOME" > /dev/null
  else
       pushd "$@" > /dev/null
  fi
}

cdback()
{
  popd > /dev/null
  printf "Returned to:%s\n" "$( dirs +0)"

}

Functions have precedence over aliases, thus we can use that to our advantage , and make each cd call pushd on every argument it is given (and if none is given, we go back to home directory , same behavior, but it's recorded)

$> pwd
/home/xieerqi
$> cd /etc
$> cd /var
$> cd /usr
$> pwd
/usr
$> cdback
Returned to:/var
$> pwd
/var
$> cd
$> pwd
/home/xieerqi

Directory stack  in other shells

csh has its own directory stack implementation, but ksh does not. You could use  Eddie's implementation

Going up with a for loop

As for going a certain number of dirs up, you could write a function that calls cd .. certain number of times. For instance, here's my custom function in .bashrc

function goUp # go up x number of dirs
{
  num=$1
  while [ num -ne 0  ];do
    cd ..
    num=$( expr $num - 1   )
  done
}
# ---

So I would call this as goUp 3 to go up 3 directories, and it would call cd .. 3 times

Using inode number
This method is good when
This trick is often used when the folder name has difficult character/unrecognizable character. We find the inode number of the directory you want to go to using stat and then use combination of find and cd

$> stat $HOME/bin/sh/
  File: ‘/home/xieerqi/bin/sh/’
  Size: 4096        Blocks: 8          IO Block: 4096   directory
Device: 801h/2049d  Inode: 5795531     Links: 2
Access: (0775/drwxrwxr-x)  Uid: ( 1000/ xieerqi)   Gid: ( 1000/ xieerqi)
Access: 2015-08-19 15:27:38.280529273 -0600
Modify: 2016-02-20 17:03:49.822700405 -0700
Change: 2016-02-20 17:03:49.822700405 -0700
 Birth: -
$> cd $(find $HOME -inum 5795531 -type d 2>/dev/null)
$> pwd
/home/xieerqi/bin/sh

Of course this might be a bit slow, because find traverses the whole directory tree recursively.


How to Run Process Manager as Super User

How would I get this process to start when the device is booted?

create a service (I used pm2.service as example)
place service in /etc/systemd/system/.
enable the service:

chmod 664 /etc/systemd/system/pm2.service
systemctl daemon-reload
systemctl pm2.service

If the 3rd command is error free system will load the service when booting.

  How do I grant this process permanent sudo permissions?

You don't. "sudo" is only for your admin user. Not for systemd as this is done by root.


Will I be able to install ubuntu touch on a Meizu MX4 with android?

according to this article it's not such a good idea.

Not all Meizu devices are unlocked, and even if they do, they have a different partition table scheme.


Should I run sudo mysql_secure_installation after installing mysql?

Yes. It would be better if you run command as it provides many security options like:

You can set a password for root accounts.
You can remove root accounts that are accessible from outside the
local host.
You can remove anonymous-user accounts.
You can remove the test database, which by default can be accessed by
anonymous users

if you want to set.


How to organise tabs in the Xfce Panel by workspace?

You try to set this behaviour for the Window Buttons plugin.

In the panel settings go to the Items tab.

Edit preferences for the Windows Buttons plugin - there are several filtering options.

Mark Show Windows from all workspaces or viewports


Can drivers create a problem while switching from 32 bit to 64 bits?

If your processor supports 64-bit then you can install ubuntu 64 bit version along with windows.Its not matter,if you already installed a 32bit or 64 bit windows os.It was better to try ubuntu-64 bit live disk before installing it on your hard-disk.


How do I automatically run modprobe v4l2loopback on boot?

Normally kernel modules can be added to /etc/modules for loading at boot time.

Add this to /etc/modules...

v4l2loopback video_nr=10 card_label="OBS Video Source" exclusive_caps=1

However, I don't know if you can pass parameters there. So here's another way to do it.

Add this to /etc/modules...

v4l2loopback

Create /etc/modprobe.d/v4l2loopback.conf

options v4l2loopback video_nr=10 card_label="OBS Video Source" exclusive_caps=1

Then...

sudo update-initramfs -c -k $(uname -r)

reboot

Confirm module loading with...

lsmod | grep -i v4l2loopback


Simply click on Second Icon from right (Session Indicator) on Unity panel and Select "Switch User Account".


Here are some suggestions you could try:

Install the packages preload and prelink. Preload monitors which programs you start after login and prefetches the libraries of those into the RAM at login. Prelink profiles where libraries are located, so they will load faster.
Check your Graphics Card driver. If you're using a AMD or nVidia card, you could try a proprietary driver. To get an overview of available proprietary drivers, open Software & Updates, then go to the Additional Drivers tab.*
Turn down the swappiness. The swappiness is the value which defines the tendency to move unused RAM content to the SWAP partition (if any) to free more RAM. Sounds nice, doesn't it? The downside: Swapping is slow. If your computer is swapping all the time, you don't have resources left for your own. The default swappiness is 60, a value far too high on desktop systems. I've turned my swappiness down to 10, but you could even go so far to turn it down to 1, or even disable it by setting 0, if you want to.
To modify the swappiness, open the file /etc/sysctl.conf in your preferred text editor as root. At the bottom of the file, add the line vm.swappiness = 10 (or any other value you want to have). Ensure that another, empty line follows. Now save and reboot.
To improve boot speed, activate boot profiling. To do this, open the file /etc/default/grub in your favorite text editor as sudo, and add the word profile into the GRUB_CMDLINE_LINUX_DEFAULT argument. It may look like this afterwards: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash profile". Now save and quit the text editor. Run sudo update-grub to load the changes into the boot loader. The next boot will be a bit slower, as the boot profile is being created. Afterwards your computer should boot faster.

If neither of above steps helps, it might be problems with some other component of your computer. Finding out which one will be a tough job... And even if you find out, there is no guarantee that there's a (better) device driver for Linux.

*If you're using a AMD Accelerated CPU, you have to install the fglrx driver in order to let the system manage the CPU speed. Else the CPU will stay at it's lowest possible speed.


a. Format it with gparted . It's very easy to use if you just make sure you take care selecting all the options you need.

Top right has a drop down box. Choose your new disc (will be /dev/sdb1).
You will get 1 big unallocated with the size of your disc. Format it with ext3/etc4 (or whatever system you want on it ;) )
You can also create partitions on it if need be.

b. No, you will need to manually add it to /etc/fstab (with gksu gedit /etc/fstab) but that's fairly easy. It will be something like this:

/dev/sdb1               /mountpoint                  ext4    defaults        1 2

make a backup of /etc/fstab 1st (with something similar to cp /etc/fstab /etc/fstab.20110614).
gparted will tell you the name of the disc but I assume it will be /dev/sdb;
mountpoint is a directory you created;
ext4 is the formatting you used (could be ext2, ext3 or a windows version).


Can't open Steam (You are missing the following 32-bit libraries, and Steam may not run)

Steam needs some 32-bit libraries in order to work.

Install the following libraries with package manager tool (apt-get, aptitude, synaptic, etc)

libglib2.0-0:i386
libdbus-1-3:i386
libwrap0:i386
libbz2-1.0:i386

Pay attention to i386 as it means 32-bit version.


installing ubuntu and starting windows isn't in boot option

If you are looking for grub loader, please enter the following command in ubuntu-

sudo update-grub

After executing the above commands, reboot and check if the grub loader appears.
I had faced similar issue where I did not get the option to install ubuntu alongside windows and Ubuntu was loaded automatically. After executing the above mentioned command, I got the grub loader where I could choose the OS to load.

Hope that helps.


System backup for testing new apps/settings

Installing applications should never do harm to your system when dependencies can be solved. If that was not the case then we should consider this a bug of the respective application.

This may not be so clear if we wanted to play with unstable pre-release versions, or if we need to remove an application and it's dependency again, as we may not be able to foresee unwanted side-effects. In addition in case we are not very organized we may forget about an application we had installed but never used. This usually is not an issue as applications only need little space on our system.

More serious are issues from changing values of system-wide configuration files, as these may not be reset so easily.

To avoid having my main productive system cluttered with many applications I don't really need, or ending up with an unstable system on installing alpha or beta versions of applications I do all this testing in a virtual machine:

How to install Ubuntu on VirtualBox?

By this we can easily revert back to an earlier snapshot, or to our vanilla backup installation. We can isolate a single new application installed in a vanilla installation, and we can also test various release or flavours of Ubuntu from a virtual machine.

The only drawback of a VM is the somewhat slower performance, some hard-drive usage, and rare bugs of the virtualization software we can not tell apart from real bugs of an application.


Your command does not use sudo to write to the log file - it (unnecessarily) uses sudo to cat /dev/null. The writing (output redirection) via the > operator is still done as your regular user.

You can do either of the following

sudo sh -c 'cat /dev/null > /var/log/btmp'

or

cat /dev/null | sudo tee /var/log/btmp

however there's really no need to cat anything; you can truncate the file equally well simply by redirecting nothing to it

sudo -i
> /var/log/btmp
exit

or by using the truncate command

sudo truncate -s0 /var/log/btmp


How can I remove gpg key that I added using apt-key add -?

First you need to find the key id of the key you added. Do this by the command:

sudo apt-key list

It will list all the keys that you have, with each entry looking like this:

pub   1024R/B455BEF0 2010-07-29
uid                  Launchpad clicompanion-nightlies

Once you have figured out which key to remove, use the command sudo apt-key del <keyid> where <keyid> is replaced with the actual keyid of the key you want to remove from your keyring.

$ sudo apt-key del B455BEF0
$ apt-key list | grep clicompan
$


Where can I find the source for libtracker-miner?

just a simple query I did to the apt-cache..

libtracker-miner-0.8-0 - tracker data miner library
libtracker-miner-0.8-dev - tracker data miner library - development files

have you installed those packages?

seems that the version of the library you need are old versions..you can even, install the new ones and do a link and see if the application runs, maybe there is some back compatibility
..anyway..if you compile it from sources...didn't it cry before?? it's strange, have you ran a ``configure'' script before compiling?


How to make resource available to the network?

Django Documentation:

  django-admin.py runserver

  Starts a lightweight development Web server on the local machine. By
  default, the server runs on port 8000 on the IP address 127.0.0.1. You
  can pass in an IP address and port number explicitly.

  Note that the default IP address, 127.0.0.1, is not accessible from
  other machines on your network. To make your development server
  viewable to other machines on the network, use its own IP address
  (e.g. 192.168.2.1) or 0.0.0.0 or :: (with IPv6 enabled).

You have to run:

django-admin.py runserver 0.0.0.0:8000

Then you'll be able to connect from network.


How to run windows-only forex application MetaTrader in Ubuntu?

You can use Wine to run Windows-only Application within Ubuntu.

Wine supports MetaTrader and you would be able to run it fine. However, you would have to use the Development Version of Wine as MetaTrader4 requires Wine 1.5.4 and MetaTrader5 requires Wine 1.5.9. Look at this link which gives further information about running MetaTrader under Wine. The latest Wine Development Release is 1.5.20 and you should install this version for greater compatibility.

Step 1 : Add Wine PPA to your software sources:

sudo add-apt-repository ppa:ubuntu-wine/ppa

Step 2 : Update your software sources:

sudo apt-get update

Step 3 : Install latest development release of Wine:

sudo apt-get install wine1.5

Step 4 : Run the executable Setup File *.exe for your version of MetaTrader to install it as you normally do in Windows.


The quickest and easiest way I found to move my files from laptop to pc was DUKTO, recommended to me by https://askubuntu.com/users/16395/rmano Thanks!

The link for DUKTO is here;
http://www.msec.it/blog/?page_id=11

Its simple to set up and use, and I believe its also multi platform. A drawback for some will be the lack of any security features meaning data could be sniffed but that wasn't a problem for me as I just plugged both devices straight into the router and unplugged the phoneline to create a superfast and secure network.

Took less than 2 hours to shift about 110gig of data so Im happy, and would recommend DUKTO :) (for use in a secure network)

Thanks for contributions

P.S. There are a number of other applications claiming to do the same or similar to DUKTO, and they might be even better


How to put Hard Block on Bluetooth and WiFi?

Hard blocks are done by the physical switch on your computer being turned off, if it is not a switch on your system then it is controlled by a key combination for example FN key + f5. We might could write a script but then you would have to enter commands to turn wifi and bluetooth on. Wifi has power management built in automatically to save power when running on battery unless you have deactivated it. You can check with iwconfig


I can use Alt-X to enter Unicode on an old machine. How is this possible?

The standard ways to enter Unicode characters on Linux are

Hold Ctrl+⇧ Shift and type u followed by the hex digits. Then release Ctrl+⇧ Shift.
Enter Ctrl+⇧ Shift+u, release, then type the hex digits, and press ↵ Enter (or Space or even on some systems, press and release ⇧ Shift or Ctrl).

https://en.wikipedia.org/wiki/Unicode_input#In_X11_(Linux_and_Unix_variants)

Alt+X is supported by many applications though, like MS Word or Libre Office. Therefore I think you've used Libre Office on one system and type on some random textboxes on the other
However using typing the Unicode code points is just for typing rarely used characters. It isn't a good way for typing common characters. You should create a keyboard layout for your own that and access those special characters through AltGr. Even better, you should use LaTeX which is more suitable for scientific documents. You can get any symbols easily with beautify formatting and don't need to remember the Unicode code points


Prevent interruption of moving file long time

Open system settings -> power and set "suspend when inactive" from 10 minutes to never.


The problem is I missing some package
check this out https://help.ubuntu.com/community/LiveCDCustomizationFromScratch


Suddenly unable to boot from Ubuntu Live USB created with Unetbootin on OSX

So, at first I was thinking it's most likely a problem with some BIOS startup settings, since that seems to be the most common problem in cases like mine, but as it turns out, that wasn't it.

Now I found a solution myself, described below. I still don't know why it works, but here's the how...

The problem seems to be that I initially created the bootable USB with UNetbootin.

Instead of using UNetbootin to create the bootable USB, I now tried the manual creation of a bootable Ubuntu USB, as described here or here (under: dd image of iso file), and it works now, both on the Thinkpad (and the Macbook).

If anyone else has an idea why the above makes the difference, please write it as an answer in here and I will mark your answer as 'solution' (unless that's against stack etiquette).


Everything looks OK so I think your installation is not complete. For mysql and php to communicate, you need to install the php5-mysql  package :

sudo apt-get install php5-mysql


How can I read GSettings values from a filesystem backup?

Suggested by a community member in the GNOME IRC channel:

Copy the old ~/.config/dconf/user to /tmp/dconf/user.
Export the data to a human-readable format:

XDG_CONFIG_HOME=/tmp dconf dump / > old-gsettings-data.txt

Optionally edit the data in a text editor and load it into the current database with dconf load.


Why does Ubuntu always boot regardless of boot priority?

If you have a SATA, SCSI, or SAS HDD, you could unplug the all of the connected HDDs prior to boot, insert the USB drive, boot it, and then plug the drives back in.

If that doesn't work, don't use the 8.04 disc, but burn a 13.04 disc, and then try the above with a disc instead of a USB drive.


Solved
My ISP decided to reassign me a new 'static' ip. I'm gonna have fun changing literally everything!


In the end of your ~/.bashrc, paste the code below:

RAW_CUR_LS_ALIAS=`alias ls || echo "ls"`
CUR_LS_ALIAS=`echo "$RAW_CUR_LS_ALIAS" | sed "s/^alias ls='\|'$//g"`
alias ls="$CUR_LS_ALIAS --time-style='+%y/%m/%d %T'"

After pasting this command, save and close the file.

And run

source ~/.bashrc

Now try:

ls -al

You'll need source only this time, when you restart all of your gnome-terminal windows, it will always load the alias automatically.

If you want to customize it by yourself just take a look at the man of date and look for FORMAT options.


Disable GUI for reminding of updates in Ubuntu 18.04 LTS Desktop

Open Synaptic Package Manager then go to Settings -> Repositories -> Updates and uncheck Check for updates.

I'm not sure how you have unattended updates set up, but if it's using a cron job then this should work fine.


Can I develop ubuntu for phones apps in Python?

It's true that PySide's future on Qt 5 is uncertain, but that's not the case for PyQt. So technically, it should be possible to do this.

Then there's the point of politics: Canonical said they will release the source code for Ubuntu Phone in due time, so it's very likely that someone hacks support for Python in it after that. If Canonical itself will support that is not clear yet, as far as I'm aware they didn't make a statement on that yet. Nor is it clear for any OEMs/operators (because there aren't any (known) yet).

UPDATE: Canonical released the source (as expected), and some operators are known now. It seems like Canonical's not planning to add Python support for the SDK themselves (at least for now), but that they're open to contributions. (Source.)


I can't uninstall Ubuntu and I have a single boot

There's no need to “uninstall” Ubuntu. Just let the Windows installer erase your harddisk.

If for some reason Windows can't erase the disk, boot a Ubuntu live CD (or USB), start GParted and erase your disk from there (Device → Create Partition Table..., select type msdos), after doing that the Windows installer should work fine.


I'm not sure about the two error messages, sometimes they're just warnings and everything still works ok.

But the funny screen size sounds like the monitor's being told to use a size it can't do. Could try changing the resolution in the Display settings

Display in the Settings sub-menu
or All Settings -> Display
or run xfce4-display-settings in a terminal to open the window

If the window opens, ALT+Space then M should let you move the window with the arrow keys, to get it somewhere you can see & change the settings. (It looks like there's keyboard keys that should change the settings, like E for resolution, but they don't seem to work for me.)

That's assuming the live USB booted & ran ok in the live "Try Ubuntu" mode... if it didn't then you might need a kernel boot code like nomodeset to get it working. Searching for your notebook's model and "Ubuntu" should find others with the same problem, and hopefully their solution.


Cannot open files from CD burned in Ubuntu

I don't know why Windows isn't able to read your files from the DVD, but if Ubuntu is able, then the solution should be simple. Boot Ubuntu and access the files. Ubuntu is also able to access Windows' filesystems, so you can copy them onto your Windows file system.


It's impossible because you have to unmount the partition and, in consequence, you should use a CD or DVD Live of Ubuntu (external Gparted). With the CD Live, you have to reduce the space around half and then copy your partition with Ubuntu in the new free space (to clone). It's recomendable that you install, for precaution, the grub of this cloned partition modifying it for including the first partition and then initialize the system.

Verify that you can boot the two Ubuntu partitions. After that, the first partition is eliminated by using again the CD Live and then install Windows. For dual boot, restore grub from the second partition of Ubuntu and modifying grub inputs for including Windows.


Is it possible to show the output on terminal while writing the output of a command to a file?

tee is designed to split STDIN into a file and back out to STDOUT.

In simple terms, just pipe it through, like so:

nmap www.somesite.com | tee file.txt

The current accepted alternative involves running nmap twice which is a horrible idea.
You'd be better off running it once to file and then outputting the file.

nmap www.somesite.com > file.txt; cat file.txt


Remove monitor overscanning to the left for a Nvidia card

Are you using RestrictedDrivers (  BinaryDriverHowto/Nvidia ), because these can be the source of the problem sometimes. For me the factory drivers proved best, on GTS 450.

Perhaps try switching back, from Settings, Additional Drivers (Xubuntu 12.04.1). Otherwise, setting 'Resolution' (and refresh) from NVIDIA X Server Settings might do the trick; instead of using auto.

PS. If you can't 'Save to X Configuration File' from the nVidia utility it usually means that X had been modified by some other means and Ubuntu is reading the settings from somewhere else now (in my experience :))

Edit: Btw., just noticed a LOT of 'related' on the right after posting.


Just upgraded to Ubuntu 19.04 but can't log in!

You may have a problem with an older computer, with an older GPU. Try this...

boot to recovery mode
choose root access

type:

sudo mount -o remount,rw /      # to remount the disk r/w

sudo pico /etc/gdm3/custom.conf # edit this file

change:

#WaylandEnable=false

to:

WaylandEnable=false

Then reboot.