What is "chmod" and its practical aspects?

I believe this breaks down into a few closely interrelated questions, which are answerable with a reasonable degree of objectivity.

Why does Ubuntu allow different kinds of permissions to be adjusted for different users and groups of users? Is this high degree of configurability really necessary?

Almost all currently used operating systems, including Windows, have this functionality. Actually, on Windows the system is more complex, because Windows uses access control lists for almost everything while Ubuntu uses the simpler system of Unix-style ownership and permissions most of the time (but also supports access control lists).

A few reasons this is necessary:

If you want your computer to be accessed by users other than yourself, you need the ability to decide that some files are totally off-limits to certain users, and that others are readable but unmodifiable by certain users.

Remember, this includes people who you might want to access your computer over a network. Such as yourself. Many people want to be able to share files between computers at home, or with their friends, but not with just anybody who happens to be using the same public wireless network. Thus users represent more people than you might actually have physically using your keyboard.
The operating system you're using--Ubuntu--is the same OS as Ubuntu Server. They have different packages installed by default, and different installers. You can transform a server system into a desktop system and vice versa. A full system of ownership and permissions is necessary for most servers, even if it may not be necessary for some desktops. The desktops work fine with it; the servers would not work without it.
User accounts can represent real people who access your computer, but they represent a whole lot more than that, too. A user account represents a collection of abilities. Special user accounts exist for performing particular tasks with constrained abilities.

The purpose of this is twofold. First, the developer of the software, or the user, could make a mistake resulting in the software attempting to perform some action that can be known beforehand could only cause harm.

Second, a malicious party might deliberately fool the software performing the specialized task into doing something bad, like destroying data or allowing the malicious person to control it.

In both of these cases, harm is often reduced if the task is performed by a non-privileged user that doesn't represent any particular human user of the computer, but exists just to perform that particular task.

If you only have a few human user accounts set up on your Ubuntu system, then most of the user accounts listed by running cat /etc/passwd are this kind of "user." (Don't worry, running cat /etc/passwd does not actually show you people's passwords; the file is called that mainly for historical reasons.)

What's the point of Ubuntu limiting my user account's access to anything, if I'm an administrator and can perform any action as root with sudo?

The same reason there are guard rails on the sides of some roads, manhole (personhole?) covers, a cover over the needle at the end of a syringe, safeties on firearms, etc. And not for the same reason that people put locks on their doors. Not to keep you from doing something deliberately that you do want to do, but to keep you from doing something accidentally that you do not want to do.

When you want/need to perform an administrative task, it is important that you be able to do it easily. Your control over your own machine must be respected, plus a system that's unnecessarily hard to use is not very good. If Ubuntu prevents you from easily performing administrative actions, that is a bug. Fortunately, this is not usually the case (though I fear we're moving in that direction). One of the reasons Ubuntu uses sudo is that it generally facilitates easily running commands/programs as root, without reducing your ability to perform ordinary, non-administrative actions concurrently.

When you're not trying to modify your system in some deep way that could be dangerous, it is similarly important that the system be designed in such a way as not to fool you into doing it.

Similarly, you probably have the right to give your life savings to some random guy. You also have the right to play tennis. Your autonomy is important; it is because of that and not in spite of it that a "give away all my money" button on your tennis racket would be a bad design.

For more information about why even administrators should use "limited user accounts" (plus the ability to perform any particular action without limitation, on demand), see:

How to NOT become a root user? Are administrators root?

I understand what user permissions are--they are permissions for the file's owner. What are group permissions for?

The owner of a file--which is usually the user who created it, or the owner of a special folder that's set up so files created it in belong to that user--can choose a group of users to "group-own" the file.

This group of users can then be given special abilities (or potentially, have special abilities taken away, though that's not generally recommended or effective) compared to everyone else.

By everyone else I mean all the other user accounts on your system, other than the file's owner and group-owner. This includes the ones that don't correspond to any human being. For example, you might want all the people who use your computer to be able to configure printers (lpadmin group) and use the CD/DVD/BluRay drive (cdrom group), but there's probably no need to allow the crash-reporting "user" (whoopsie) or the clock-syncing "user" (ntp) to have these abilities.

You can use groups to manually implement access control if you like, but on desktop systems, often most groups are automatically configured and managed. The groups command will list all the groups you're a member of.

What are "other" permissions for?

They apply to everyone else--to user accounts that neither own the file nor are members of the group-owner.

Are group and owner file permissions just for servers?

No, they are used to manage distinctions between different kinds of user accounts on your machine, including non-human "user" accounts. This applies even if there is only one human user account on your system.

For example, membership in the adm group (which does not make a user an administrator) confers the ability to read the contents of most systemwide log files. This is a relatively harmless ability for just about any human user of most desktop systems, but could potentially lead to problems if it were conferred to part of the system that perform only a highly specialized task (that is, it performs only that task unless something like a partially successful cyber-attack is perpetrated).

Are group and user file permissions more important on servers than desktops?

Sort of.

On servers you are more likely to have to be aware of them and manage them manually, because you are more likely to deliberately provide and deny access to a variety of resources for a variety of human users.

But they are necessary for the system to work correctly even for a single human user. The system would have to be designed quite differently to work well in a single-user mode for everyday computing, without a system of file ownership and permissions.

By way of comparison, consider I/O scheduling. Many server environments have many more processes accessing many more files than many desktop systems. Therefore, input-output scheduling (managing how limited throughput can be managed to complete file access transactions with reasonable efficiency) is especially important on (some) servers, compared to (most) desktops. Server administrators are more likely to study I/O scheduling and to make changes to the way it works on their computers, than most desktop users. But I/O scheduling is necessary for either a server or desktop system work.

As the owner of a file, I can change all its permissions and as well as its group-owner. I can do this without sudo or a similar mechanism! So what's the point of permissions?

The owner of a file can do this without being root (i.e., without sudo), but other non-root users cannot. This includes the non-human "users" that are part of the system (see above).

Furthermore, many files on the computer are not "owned" by your user account. Those files do require that you authenticate in some way, to modify their permissions. You do have to use sudo (or a similar mechanism) to change permissions on system files owned by root.

Finally, there is some value associated with having permissions that apply only to you, even if you can change them without using sudo or any similar mechanism.

What are user permissions for? Why would I want to change what I can do with a file, when I can just change it back?

For the same general reason you may want to make a file read-only (even though you can override it yourself), you may want to make a file that you cannot read or execute (run).

The more common situation is that you may not want a file you own to be executable by you. When you download something, you probably don't want it to be marked executable because it could be malware. You probably want the opportunity to consider if you want to run it, before marking it executable. Furthermore, if you downloaded a file whose name ends in .pdf but is actually a malicious program, you definitely don't want execute permissions to be set on it by default.

There is another reason that's less related to security. Any file marked executable is treated as something that can be run--a program or script. Most files are neither, and you would not want to be given the opportunity to run them.

For example, if a text file is marked executable (for example, you own it and it has the execute permission turned on for its user-owner) and you double-click on it in Nautilus (the file browser), it will run. But most text documents are not scripts, and you don't want to try to run them when you double-click on them; instead, you probably want to open them in an editor.

It's less common to want to create a file that you cannot yourself read (without changing its permissions back). One situation where you may want to do this is if you had several files and wanted to avoid opening one of them for a while, for example if it is huge and takes several minutes to open. I've been in this situation, where I had to keep waiting for an application to finish opening a file so I could close it because I'd selected the wrong file (again).

A related possible scenario is if you are automatically performing some action on many files (a "batch" job) that reads from the files, but you want it to skip some. Provided that the action will "degrade gracefully," continuing to do what it can after an error, the easiest way to accomplish it might be to mark the few files you want to skip reading as unreadable.

A very different situation is: maybe you want to deny read permission to yourself on some file because the file serves some purpose other than containing data. Files can be used to signify some condition. As a made-up example: some search application that indexes files might first check to see if a file called noindex is present in your home folder, and stop if it finds. That file doesn't have to be read; arguably, marking it unreadable helps clarify its purpose.

Wanting to keep yourself (or some task you're performing as you) from reading files you own is not a particularly common situation, though. And in practice, most "signal" files (that exist because their existence itself means something) are readable by their owners. Really, as far as I am aware, there are three primary reasons for the user-owner of a file not to be able to read it, and even to be able to write to it without reading it:

Group and other have read, write, and execute bits, and they can take on any combination of values. There is no compelling reason to break with this model--thereby making the system more complicated--for the user who owns the file.
Many resources that we don't usually think of as being file-like are represented by entries in the filesystem. For some resources, it makes sense to write to them, but does not make any sense to read from them. For these resources, the read bit is sometimes turned off for everyone, even the owner, and even if the owner is root. (Not always, though; for reasons that are both beyond the scope of this answer and at the edge of my own knowledge, some write-only devices' filesystem entries still have their read bits enabled for some users.)
The ability for a file to deny read access even to its owner is sometimes used to represent files on a write-only filesystem. (Not always, though; it depends on the details of the filesystem and how it is mounted.) Write-only filesystems are uncommon but they do exist and have practical uses.


What kind of cypher do Ubuntu uses on its full disk encryption?


Its because your GPU (or the driver being )is not supported for WebGL.
Its browser blacklisted.

However you can force enable your GPU for WebGL.

Warning: Do this at your own risk. It can harm your hardware. There are usually good reasons (like some critical driver bug) why features are blocked.

To launch chrome ignoring the black list, run following after pressing Alt + F2 OR in terminal

google-chrome --enable-webgl --ignore-gpu-blacklist

Configuring firefox:

To force-enable WebGL, go to about:config and set webgl.force-enabled=true.
To force-enable WebGL anti-aliasing, go to about:config and set webgl.msaa-force=true.
To force-enable Layers Acceleration, go to about:config and set layers.acceleration.force-enabled=true.

More reads on firefox blacklisting.


Uninstall yesterday's synaptic packages with virtual terminal on Ubuntu 14.04

Try to see what was made that day, go to file history.log located in /var/log/apt.
You can use sed command:

sed -n -e '/Start-Date: 2014-05-10/,/End-Date: 2014-05-10/ p' /var/log/apt/history.log

In that way you can find packages names. Or put that output to a file:

sed -n -e '/Start-Date: 2014-05-10/,/End-Date: 2014-05-10/ p' /var/log/apt/history.log > filename.txt


Keyboard not responding on Ubuntu 18.04 LTS

To solve the problem:

Click the down arrow on the top right corner near the Shutdown sign
Go to Settings
Click on Universal Access
Go down and click on Typing Assist (AccessX)
On the pop-up message toggle Bounce Keys to ON


bash script source: No such file or directory

~ doesn't appear to be expanding properly. When I run your script with an intentionally fake path, the error doesn't say ~, but expands the path (i.e. /home/sparhawk/fakepath not ~/fakepath. You could try using $HOME instead of ~, or using the full path in the script instead.

(I'm not sure why ~ doesn't work on your system, as your script works fine for me.)


Not able to login through GUI in Ubuntu 12.04

The following lines (taken from /etc/profile on my Debian box) seem to be what you're missing:

if [ "`id -u`" -eq 0 ]; then
  PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
else
  PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games"
fi
export PATH

add them after the first two lines (the comments) and retry your log in.


Ubuntu 16.04 Brightness & Lock - Screen does not turn off

I found out there was a bug related to this unexpected behavior. Bug #1292041.

This got fixed recently with the release of a Unity patch.
See https://bugs.launchpad.net/ubuntu/+source/gnome-screensaver/+bug/1292041

After updating the OS, it now works well on my setup, the monitors blank off, and stay that way until I hit a key or move the mouse.


You don't seemed to have run sudo make install  or if you did you did not paste that output above.

If you believe you have done so, please update your question with that paste and also include the output of echo $PATH; ls -l /usr/local/bin

If you did not do so, what was the documentation failure which led you to try -C contrib?

Thanks


How to add image at the background of terminal in Ubuntu 13.04?

Open terminal, go to Edit - Profile Preferences and select Background tab. Choose Background Image and select a file.


(Comment from OP fixed issue)

Sounds to me like X (the graphical server) is crashing at some point and it's just reloading (that's why you're being pushed back to the login screen). If you have a network connection please run sudo apt-get install pastebinit, then pastebinit /var/log/Xorg.0.log and then post the URL it generates back here so we can see what X did last time it loaded. – Oli♦ Oct 20 '11 at 1:0

Ok i seem to have solved the problem. I was unable to access my home directory when I was using the console so i changed the permissions of it to 777. When i restarted my computer i was able to login. Very weird. – matthew Oct 20 '11 at 1:12


Remap Keypad Ins/0 key to Right Arrow Ubuntu 14.04

The following solution has worked for me in 16.04 and believe it should be similar.
First of all, why don't you just use the keypad with Num Lock off and use the 4 key as a right arrow?
Anyway, if you want to remap the ins/0 key, you need to do this in the file /usr/share/X11/xkb/symbols/keypad. In there, edit the line

key  <KP0> {  [  KP_Insert,   KP_0    ]   };

to

key  <KP0> {  [  KP_Insert,   Left    ]   };

This will make this work as left with Numlock off
or

key  <KP0> {  [  Left,    KP_0    ]   };

to work with Numlock on. (Quite self explanatory).

Hope this helps


How to write the path of a folder with space in its name?

You can enclose the whole path by double-quotes ("), single-quote (') or escape the space character using a backslash (\) :

cd "/path/path/path/A Folder/file"
cd '/path/path/path/A Folder/file'
cd /path/path/path/A\ Folder/file


Dependenncy problem - Cannot reinstall PulseAudio

Ok, I've been defeated. Thinking it would be the pinnacle of cleverness, I installed the required libpulse0 library from a downloaded package.

...it didn't go well. Immediately afterwards apt told me that something like a hundred packages were not needed anymore, and the audio was still not working. I rebooted my laptop and, surprise, the desktop environment had disappeared, and there was only the command line.

I've just finished reinstalling everything (thank the linux gods for home partitions).

Sorry to all those who'll land here in search of a solution.


bumblebee with optirun/primusrun: timeout after ~ 1 minute

As usual, I've found the solution myself ~ 5 minutes after posting the question: I had edited my firewall settings, and they were too restrictive - in particular, they prevented bumblebeed from connecting to the X server via port 8001. Firewall settings adjusted, everything back to normal :-/

(Edited the follow up comments back into answer -Editor )

I used netstat -altup and saw that bumblebeed was in SYN_SENT state, which usually means that the initial connection was silently dropped by the firewall.


Global proxy setting can be defined on the following file: /etc/apt/apt.conf, or alternatively you may export proxy settings, please see: apt.conf and  exporting


How do I get my Dock to appear on the left in Ubuntu 20.10?

In Ubuntu, the dock comes to the left by default.
In your case, it looks as if you have the extension "Dash to panel" installed. That combines the dash and the panel into the area on the bottom by default.
To solve your issue, disable the extension "Dash to panel" and (re)enable the extension "Ubuntu Dock".


Invisible audacity session running won't let me start audacity

This bug also happens after a power failure.  There is a lock file at /var/tmp/audacity-myusername/audacity-lock-myusername that does not get cleaned up after a hard shutdown.  It will frustratingly prevent any new instances of audacity from being launched, even if you have no current instances running.  Delete this file, and you're good to go.


Make sure that you have a good backup of your important Windows and Ubuntu files, as this procedure can corrupt or loose data.
This is a two part process. Resize the Windows NTFS partition, and move/resize the Ubuntu partition.
In Windows...

temporarily disable the pagefile using the System control panel
reboot
defrag
use the Disk Management app to resize the Windows NTFS C: partition
open a CMD (command) terminal with admin privs
issue a chkdsk /f C: and confirm to do this on next reboot
reboot, observe chkdsk running
reboot and confirm that Windows still boots
re-enable the pagefile
reboot and confirm that Windows still boots

For Ubuntu...
Keep these things in mind:

always start the entire procedure with issuing a swapoff on any mounted swap partitions, and end the entire procedure with issuing a swapon on that same swap partition

a move is done by pointing the mouse pointer at the center of a partition and dragging it left/right with the hand cursor

a resize is done by dragging the left/right side of a partition to the left/right with the directional arrow cursor

if any partition can't be moved/resized graphically, you may have to manually enter the specific required numeric data (don't do this unless I instruct you to)

you begin any move/resize by right-clicking on the partition in the lower pane of the main window, and selecting the desired action from the popup menu, then finishing that action in the new move/resize window

Do the following...
Note: if the procedure doesn't work exactly as I outline, STOP immediately and DO NOT continue.

boot to a Ubuntu Live DVD/USB
start gparted
move /dev/sda6 partition all the way left
resize the right side of /dev/sda6 all the way right
click the Apply icon
reboot


What is the command in the terminal to update Vim on Ubuntu?

To get the latest stable version, it is recommended by the official instructions to directly install it from the source GitHub repository.

$ git clone https://github.com/vim/vim.git
$ cd vim/src
$ make
$ sudo make install

You can also use apt-get update && apt-get install vim to update Vim to the latest version available in your distribution's packages registry. To update all available packages, you can run apt-get update && apt-get upgrade

However, you may not get the latest version of Vim with APT (you'll moszt likely the latest major version, but not the minor / patch versions).


Change resolution Ubuntu over Teamviewer

You must change resolution on computer with Ubuntu 14.04.1.
You have wiki here


GRUB remains on drive after formatting , cant boot from cd/usb

Format the drive using gparted and creating a new partition table in the MBR format. That will completely wipe the disk of grub, though it really won't affect your ability to boot to the disk drive, try pressing f12 at boot when the bios screen comes up and select cd drive. Wiping grub off the disk is done by the windows installer, and it does nothing to obstruct the cd boot process.


How do I take pictures with asus 1015cx?

Webcam? Checkout Cheese via sudo apt-get install cheese.


Can't launch some installed apps Ubuntu 18.04.3

Most importantly: Linux is case-sensitive. "gparted" and "Gparted" are not the same program name, and only the first is right.

To see if a package ( which contains a program AND the program's ancillary files) is installed, use the terminal command dpkg -l packagename (dpkg -l gparted). To see a list of the files installed by a package use the terminal command dpkg -L packagename (dpkg -L gparted).

To get from a file on your system back to the package that installed it, use the terminal command dpkg -S filename (dpkg -S /bin/bash or dpkg -S $(type -p bash) ).


Learning material for boot configuration

UEFI boot: how does that actually work, then? is still a good read for understanding UEFI. Even if you don't have a UEFI capable machine, start with this article.

After that you can read through and compare the articles on EFI and BIOS as well as Windows NT startup process and Linux startup process. The UEFI article on the Arch Wiki is a good cheat sheet to look up how to do certain things, but remember that some of these are Arch specific, but as Arch intents to teach users how configuration is done, this isn't bad, just lenghty.

I completely agree with Rinzwind's comment: make and verify backups!


Freemind doesn't get started in Ubuntu 14.04 32-bit

Ubuntu announced its 13.10 (Saucy Salamander) release almost 9 months
  ago, on October 17, 2013. This was the second release with our new 9
  month support cycle and, as such, the support period is now nearing
  its end and Ubuntu 13.10 will reach end of life on Thursday, July
  17th. At that time, Ubuntu Security Notices will no longer include
  information or updated packages for Ubuntu 13.10.

  The supported upgrade path from Ubuntu 13.10 is via Ubuntu 14.04 LTS.
  Instructions and caveats for the upgrade may be found at:

Upgrade from 13.10 to 14.04

  Ubuntu 14.04 LTS continues to be actively supported with security
  updates and select high-impact bug fixes. Announcements of security
  updates for Ubuntu releases are sent to the ubuntu-security-announce
  mailing list, information about which may be found at:

Ubuntu Security Announcements

Or read about How to install software or upgrade from an old unsupported release?

source: http://fridge.ubuntu.com/2014/06/20/ubuntu-13-10-saucy-salamander-reaches-end-of-life-on-july-17-2014/


Stuck on boot after adding fsck.mode=force

After a reboot and repeat of the process, fsck finished within 10 seconds (no errors). Maybe fsck invisibly waited for input or the stuck boot process had nothing to do with fsck at all.


The default device automatically uses a plugin that can mix multiple streams together.

Try using default:DG2 (but this will not work if the other program does not also go through default).

Run lsof /dev/snd/* to see which programs are accessing sound devices.


How to assign a Vim as the default program for a file type and run it in maximized terminal?

For files handling in gnome you will have to use the graphical version of vim called gvim, to install it type sudo apt-get install vim-gnome.

Has an option you can create a .desktop file that will be listed on 'Open with other application' tab:

Navigate to ~/.local/share/applications
Create a file called vim-console.desktop with these contents:

[Desktop Entry]
Encoding=UTF-8
Name=Vim Text Editor (Console)
Comment=Edit text files in a console using Vim
Exec=gnome-terminal --full-screen --execute bash -c "vim %u"
Terminal=true
Type=Application
Icon=/usr/share/pixmaps/vim.svg
Categories=Application;Utility;TextEditor;
StartupNotify=true
MimeType=text/plain;
NoDisplay=true

After this you will see Vim Text Editor (Console) in your Open with other application tab, select it and when you double click the file you will be able to open it using vim terminal editor.


How to enable dual monitor with an ATI Radeon X300 card?

Set a larger maximum size for the virtual screen.

Create a file /etc/X11/xorg.conf if it doesn't already exist and add content

Section "Screen"
Identifier "Default Screen"
Device "Default Video Device"
SubSection "Display"
Virtual 2720 1024
EndSubSection
EndSection

In Virtual X Y, X and Y should be the screen size or larger than that appears in the error message.


How to install GPU Ocelot in Ubuntu 14.04?

Installation

If git is not installed, install it:

sudo apt-get update && sudo apt-get install git

Checkout Ocelot from github:

git clone https://github.com/gtcasl/gpuocelot.git

Optionally: Install boost

sudo apt-get install libboost-all-dev

Optionally: Install compiler tools

sudo apt-get install flex bison g++ scons

Enter the gpuocelot/ocelot directory

cd gpuocelot/ocelot

Run the build script.

sudo ./build.py --install

This will install the Ocelot development headers and libraries:

libocelot.so

Create the necessary system links to the Ocelot library so the dynamic linker will find it:

sudo ldconfig

This library can be used to access the tools within ocelot or linked against a CUDA application compiled with NVCC to emulate a CUDA device.

Alternatively, there is a new utility, OcelotConfig that is intended simply the process of linking against Ocelot.

To link a program against Ocelot:

g++ -o my_program my_program.o OcelotConfig -l

Refer this link for more details.


How do I find out what my default terminal text editor is?

In Ubuntu, there is a generic editor command which is set by the Debian alternatives system.

If you do:

editor foobar.txt

the file will be opened using the original editor e.g. vim, nano which is prioritized as editor currently.

You can check the details with:

update-alternatives --display editor

To set a new editor as editor:

sudo update-alternatives --config editor

Also note that bash checks some environment variables for tasks related to it, to be exact bash checks VISUAL, EDITOR one after another. If unset, bash defaults to emacs.

Some processes spawned from bash check these environment variables too.


Intel UHD 630 works significantly better than NVIDIA RTX-2060(Mobile) on Ubuntu 19.10 & GNOME

Known Gnome bug on hybrid graphics hardware (with workaround): https://gitlab.gnome.org/GNOME/gnome-shell/issues/1202#note_524388


Have you tried holding down F6 during a cold boot, select language, then F6 again to get the options on the lower right to show up. Select nolapic, EDD=On, and nomodeset. Press ENTER. Next, down arrow to the second line which is the Install line. DO NOT PRESS ENTER OR A LEFT OR RIGHT ARROW!! Now back space and delete quiet and splash with nomodeset. Now press ENTER. The installation will begin and if it hangs up now, you will see what was the last process/script that completed.


You could try looking through the themes over at gnome-look.org anything under the "GTK3" category in theory will work with both Unity and Gnome-shell. This rule should also work for icons as well.

References:

Gnome Look

Good reference info from the Ubuntu forum


Mounting Fedora 25 LVM partition returns unknown filesystem type 'LVM2_member'

You need to mount the LVM logical disk, not the LVM physical disk. In your specific case, you want to mount /dev/fedora/root.

 fsck -p /dev/fedora/root
 mount /dev/fedora/root /mnt


modprobe: FATAL: Module rtl8723de not found. Ubuntu 18.04 on HP Pavilion

07:00.0 Network controller [0280]: Broadcom Inc. and subsidiaries BCM4312 802.11b/g LP-PHY [14e4:4315] (rev 01)

Above information from your lspci output tells that you have BCM4312 wireless. You will need wired Internet connection to fix it.
Open Terminal and type:
sudo apt install b43-fwcutter firmware-b43-installer
This should solve the problem. You might need sudo apt update before if it's a new install of Ubuntu.
Reboot the computer.


"Internet not working" message, when I try to update Ubuntu, when internet is working fine

This is not a error with your computer. Because there is no such a file(linux-headers-3.0.0-19_3.0.0-19.32_all.deb) in the "in.archive.ubuntu.com" server.

Try to run apt-get update && apt-get upgrade

If this not works change the repository mirror. [/etc/apt/sources.list]


Unable to change permission of the files on mounted partitions in ubuntu 12.04 LTS

Went through exactly the same issue. This page perfectly solves the issue. pysdm is the solution. The GUI has all options that you can configure.


Nautilus show folders before files does not work in Ubuntu 18.04 LTS

You can change this from the Nautilus preferences.
Open the context Menu from the top-right of a Nautilus Window:

Tick 'Sort folders before files'.

If that doesn't work you can edit the Dconf file directly, the easiest way is using the Dconf Editor:
Install Dconf Editor (sudo apt install dconf-editor), open it and then navigate to:

org → gtk → settings → file-chooser → sort-directories-first and set it to True.

Alternatively, run this command in the terminal:

dconf write /org/gtk/settings/file-chooser/sort-directories-first true


Why does firefox keep saying having trouble getting your pages after upgrading to 18.04?

OK I had a play with firefox settings.  First off I turned restore session ON.  A bit odd it was trying to restore sessions when it was turned OFF?  Then I turned it back OFF.  This made things a lot better but I then noticed Easy Image Blocker addon was playing up.  It was blocking images at start up even when I had set it t show images.  So I uninstalled this addon and replaced it with ImageBlocker.  All seems well now!


Monitor log file event it was deleted and created again

Tail is still looking at the file that was deleted. Defaut behavior. What you want is the --follow=foo.csv option which follows the name not the descriptor. see man tail.

  With  --follow  (-f), tail defaults to following the file descriptor,
  which means that even if a tail'ed file is renamed, tail will
  continue  to  track  its  end. This  default  behavior is not
  desirable when you really want to track the actual name of the file,
  not the file  descriptor  (e.g.,  log  rotation).   Use  --follow=name
  in  that  case.  That causes tail to track the named file in a way
  that accommodates renaming, removal and creation.


How to get Nvidia graphics working on Sony Z laptop?

Download the latest drivers from nvidia.com and then use this tutorial to install them:
http://forums.linuxmint.com/viewtopic.php?t=96260&f=42


If you've never run an package list update on the server, apt might not be able to see the package. The following should work:

sudo apt-get update
sudo apt-get install librsvg2-bin


Where would the stdout output by `~/.profile` have gone when starting Ubuntu?

Depending on the login manager you use, ~/.profile is not even executed when you login graphically, see https://superuser.com/questions/752493/profile-in-lxde#847051.

Also, in case it is executed (more technically correct "sourced"), the output to standard output will most likely be discarded.

If you want to write a log message, you could use the logger command (http://manpages.ubuntu.com/manpages/artful/man1/logger.1.html) to write to the system log, simply by piping your output into the logger command like this:

myCommand | logger


How to add a program as a startup application from a terminal?

In your home directory, there's a folder called .config/autostart. Anything placed in this folder will be run when you login. This could be accomplished through the command line by creating the .desktop file with the command nano ~/.config/autostart/blah.desktop. If you like to find out about the syntax of .desktop files, you can visit Freedesktop and Gnome.


Disable window decoration for specific applications

If you're using Compiz/Unity, you can do this from the infamous CompizConfig Settings Manager, but it's a bit tricky.

The "Decoration Match" key in the Window Decoration plugin specifies the windows that do have decorations. To selectively disable window decorations you have to construct an expression that matches every window except the ones you want to disable.

For example, if you want to disable window decorations for windows whose titles end in "Mozilla Firefox" or "Chromium", you can set the decoration match to:

(!title=Mozilla Firefox$) & (!title=Chromium$)

Complete documentation for Compiz window matching is at http://wiki.compiz.org/WindowMatching


Ubuntu 20.04: black screen when reboot after unplug from thinkpad thunderbolt dock station

This is a known issue with amd gpu. It has nothing to do with the dock.
Either upgrade the kernel >=5.6 or add a kernel parameter "iommu=soft" would solve it.


How to set nautilus width and height when running from command-line

The basic command option is to add (width x height) is “–geometry=WxH” option .

Here is the command you can try it and specify your own options :

First :

killall -9 nautilus

Then :

nautilus computer: --geometry=860x480


Ubuntu installation freeze from USB (Gigabyte P15)

Change the Boot mode from UEFI to Legacy in BIOS setting. Then check.
If there is only UEFI mode then it will work slow.


apt-get not working behind restricted internet access

Do you have a proxy at your company?
If so, you can set the proxy before running the apt-get update logged in as root first:

export http_proxy=http://host:port
apt-get update

Using sudo:

sudo http_proxy=http://host:port apt-get update

If your proxy requires authentication, you can set it in the URL (beware that the password will be saved in history as plain text):

http://username:password@host:port


Where can I find the MySQL Workbench dependencies?

I used Daniel Mota's documentation a bit, but needed to modify some of his commands:

You can get the necessary mysql workbench deb here

First run the following:

sudo dpkg -i mysql-workbench-gpl-5.2.40-1ubu1104-i386.deb

As you know this will fail about the dependencies. Then wget and install the following:

wget https://launchpad.net/ubuntu/+archive/primary/+files/libzip1_0.9.3-1_i386.deb
wget http://launchpadlibrarian.net/94563300/libmysqlclient16_5.1.58-1ubuntu5_i386.deb

Next install:

sudo dpkg -i libzip1_0.9.3-1_i386.deb
sudo dpkg -i libmysqlclient16_5.1.58-1ubuntu5_i386.deb

If you're using 64bit, you'll want this instead:

wget https://launchpad.net/ubuntu/+archive/primary/+files/libzip1_0.9.3-1_amd64.deb
sudo dpkg -i libzip1_0.9.3-1_amd64.deb

wget http://launchpadlibrarian.net/94808408/libmysqlclient16_5.1.58-1ubuntu5_amd64.deb
sudo dpkg -i libmysqlclient16_5.1.58-1ubuntu5_amd64.deb

Then run the following:

sudo apt-get -f install python-paramiko libzip2 libmysqlclient18 mysql-client mysql-common python-pysqlite2 libdbi-perl libdbd-mysql-perl libplrpc-perl libnet-daemon-perl mysql-client

This too will fail, and ask you to re-run, just re-run it again:

sudo apt-get -f install

When that completes it should be installed for you, leave a comment if you run into any snags and I'll try and see if I can help you further.

Launch it once from either your terminal mysql-workbench or Unity Dash, once it's in the launcher, right click on it and select "Lock to Launcher".

I have not used this program to know whether or not it is stable after installation, YMMV.

In the comments Peter K. let me know this was not working in Ubuntu 16.04. So here is the easiest way to get it working in Xenial. I still followed the link above to get the latest mysql workbench deb file (MySQL Workbench 6.3.7 at the time of this correction)

This is how I pulled it down and placed it in /tmp :

wget -P /tmp http://dev.mysql.com/get/Downloads/MySQLGUITools/mysql-workbench-community-6.3.7-1ubu1604-amd64.deb

I used the chmod command in order to make the .deb file executable, then used dpkg -i to install it (use sudo if you are not switched to root alread):

chmod +x /tmp/mysql-workbench-community-6.3.7-1ubu1604-amd64.deb
sudo dpkg -i mysql-workbench-community-6.3.7-1ubu1604-amd64.deb

You will see the failed dependencies:

dpkg: dependency problems prevent configuration of mysql-workbench-community:
 mysql-workbench-community depends on libtinyxml2.6.2v5; however:
  Package libtinyxml2.6.2v5 is not installed.
 mysql-workbench-community depends on libzip4 (>= 0.10); however:
  Package libzip4 is not installed.

To remedy this, use apt to help resolve (fix) the dependencies:

sudo apt-get -f install

This will show you the missing dependencies allowing for you to install them without any further steps.

The following additional packages will be installed:
  libtinyxml2.6.2v5 libzip4
The following NEW packages will be installed:
  libtinyxml2.6.2v5 libzip4

You should now be able to launch mysql-workbench in Xenial.


You can now under Chrome run APKs, using this extension (bearing in mind it is in development for use by developers for testing apps). Here are some steps I did to get it to work

Install from here -  click 'Add to Chrome'

This will take a while as it seems to download a crx installer weighing in at 113Mb, and another one at around 9Mb, so be patient:

N.B. on my Fedora 21 build of Chromium 40 I got the error 'Manifest file is invalid' when trying install the extension, even after clearing data and reloading the extension. I also had issues with Ubuntu 14.04's build of Chromium 41, so I installed Google Chrome :( and that worked.
Get a APK of the application you want to use - no, it does not seem like you can install from Google Play, you need a APK file of the app, so this is the tricky bit. Most closed source devlopers don't want their stuff freely distributed, so for most apps on Google Play at least you either need to use:

Use a APK for a open-source app - for testing this I tried using the x86 APK for VLC Media PLayer, which resulted in a error screen - I then tried the armv7 arc version and that worked at first and then crashed.
Get a APK from a Android device - this easily easily be done on some rooted Android devices, on normal devices I think you can copy system app's apks from /system/apps or somewhere - again not recommended due to legal stuff.
Use a third-party service/repository of APKs - e.g. this article suggest this one, but the issue here is that you may be downloading modified or infected programs/files. Probably should be considered a last resort.
 Use a third-party extension - e.g. this one that pretends to be a device and downloads (not a good idea if you like legal stuff, plus google tracks your every move (mainly when signed in) so may be found out pretty quick...  Dead as out of date on both browser and likely android support. It isn't recommend to install extensions not in browser's extension store anyway!

Install it

Now we get to the more fun bit of trying it out. Go to the Apps thing in chrome (or type chrome://apps in the URL bar) and launch Arc Welder. Then choose the directory the APK is in and then the APK, then choose 'Launch App' in the window.

If the window shows the app icon as one that looks like this:the app probably won't work so their may not be much point in continuing. This seemed to happen alot with apps for Android 4.4+...
Use it

I managed to get QuickOffice to run and mostly work under the extension, though I couldn't save any documents as it was not happy about choosing the place to save the file (showing a folder selection box, not a file selection box for saving :P )

After you press 'Launch App', the extension automatically adds a entry to the apps page on Chrome - this you can make into a standalone application launcher to launch the app directly from your app menu/dash/launcher - this is possibly the best feature of this extension as integrates with the desktop and you don't need to launch a emulator etc first.

Overall this is brilliant, considering this probably is still in development and not designed for this it works quite well.

Sources:

Getting Started with ARC
Android apps to run on Windows, Macs and Linux
Test Android apps in Chrome OS, Windows, OS X, or Linux using ARC Welder Chrome app

Alternatively you can use a emulator as suggested in other answers - I did have some success using Genymotion (there were some handy instructions here, but this answer may help). Android Emulator can be got as part of the Android Studio SDK, however since Android Nougat apps should be signed.


Did you try to change the settings of the mouse in the control center?

If it still does not work, run synclient -l in the terminal and provide us the results.


CUPS on Ubuntu is started by Upstart via the file /etc/init/cups.conf. The file /etc/init.d/cups is ignored. /etc/init/cups.conf is not an init script, but a configuration for Upstart. It does start the main daemon, and is not only a pre- and post- configuration for CUPS.

The service and initctl utilities report unknown job when the variable UPSTART_SESSION is set in the environment because in that case, the two utilities are acting on the session init and not the system init (cups is started by the system init). su usually preserves the environment, while sudo does not, so sudo initctl status cups will work but su -c "initctl status cups" will not.


Is it possible to print multiple (and different) photos from Shotwell?

When in shotwell, highlight the images that you want to print, or Ctrl click on the images that you want to print, and then click on File --> Print

Click on the Image Settings tab --> click on Autosize, choose the number of images per sheet, and then click print.


sudo evtest

  should give you a list of devices you can get scancodes for. One of them should have the foot pedal's name, so input the eventnumber you can see beside it. Then, once you use the pedal, you should see the scancode on the screen (after (MSC_SCAN), value).
  For example, here:

Testing ... (interrupt to exit)
Event: time 1413649733.746534, type 4 (EV_MSC), code 4 (MSC_SCAN), value 70005
Event: time 1413649733.746534, type 1 (EV_KEY), code 48 (KEY_B), value 1

  It's 70005.

source: Get keyboard scancodes in recent versions of linux


In some Ubuntu versions by default, it won't support MTP mode.So you have to connect your phone in Mass storage Mode to view it's contents on Ubuntu PC.


This happend to me, too, on my Ubuntu 20.04 installation. The mouse cursor moved smoothly on the login screen after rebooting, but started jumping after I logged in. It also was still jumpy on the login screen after locking the display.

Turns out I had accidentally turned on zooming using a keyboard shortcut. After disabling zoom in universal access, everything turned back to normal (thanks @iphipps).

A hint to zoom (or some other assistive tool) being turned on is the standing human character icon in the toolbar top right corner. The icon disappears when none of those tools are enabled.


Wi-fi Atheros pci.id 168c:0042, problem while wifi driver installation

Please install the headers package. With a working internet connection, open a terminal Ctrl+Alt+t and run:

sudo apt-get install linux-headers-generic

Then try your compilation again. Post any errors and we will be happy to help.


Stuck In Emergency After Trying To Mount Drive

Took hours of research but I finally found the solution.

When boot into emergency mode, press enter to enter maintenance.

You'll already be root and have read write permission so just type vi /etc/fstab to edit the fstab file which is what decides what gets mounted in boot I think.
Delete your changes by using the arrow keys to go down to where you made the change, and use the delete button to remove the changes.

After that, type :wq which saves the changes and finally type reboot

Done!

By the way, I think the guide made my system fail because the name of my drive had a space in it. System76 recommends not adding spaces to drive names so maybe that's the case.


At first boot up only background is shown, how do I continue?

Try to drop into tty1-6. The keyboard map is usually Ctrl+Alt+F[#].

Example:

Ctrl+Alt+F1 - tty1
Ctrl+Alt+F2 - tty2
...

Once you're at the command line you can try to figure out why the boot into the GUI failed.

Try checking the logs.


Edubuntu inappropriate Kernel for installation

VirtualBox is indicating that the PAE support is not present in your computer.  The following link may provide you with what you need to do to help with this situation. Virtualbox install 12.04 guest: "pae not present"


Got this error when trying to install avast

You are trying to download a Windows executable (.exe), those don't work on Linux unless you use a wrapper like wine. More importantly, you don't need an antivirus on Linux. While there are actually a few viruses around, they are either harmless, or very old and in any case you can safely ignore them.

I have been using Linux at home and professionally for more than 15 years and have never, ever, needed to install an antivirus. If you really want to, just install one that has a Linux version.


Which Ubuntu (git) linux kernel tree matches my installed kernel?

The repository you are looking for is http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-trusty.git;a=summary


No cursor output on the sceen when typing password in terminal

The Terminal by default does not show or display characters when you type passwords, all you'll see is nothing...but your password is still being accepted and the command will still run.

Just type your password and hit Enter. If you typed your password correctly, there should be no problems. If your password is incorrect, then you'll get the same prompt asking you to retype the password.


sorry to hear about the issue

With all the Dual boot installations I have done, the Installer/Setup process always detects the alternately installed OS with no issue/problem.

I have on a usual setup 1xWindows, 1xDebian (or other Linux), 1x Ubunutu

Why aren't you able to reinstall Windows - any specific Error?

Also consider adding your Windows into Grub manually if you didn't break the Partition structure.

How to add Windows 7 to Grub ?


Limit Unity's Scope to Virtual Workspace?

It's not through unity, but alt-tab switching prefers the last one opened on the current workspace, at least for me.  It also doesn't remove non-current workspace from the hover list or give you a picture of the window though.  Depending on your situation it could work.


all sound missing! EDD information missing! Help to modify Kernel?

After much searching, this is the only post I have found with my exact problem.  I have tried many fixes and I have not solved it entirely, but I was able to make some headway with this:

sudo apt-get autoremove pulseaudio

reboot

sudo apt-get install gnome-alsamixer

I did lose the volume icon in the system tray and I still don't have sound, but the system no longer freezes when trying to produce sound or access sound settings.  Also, I no longer get the Gnome-settings-daemon not responding message/force close upon shut down.

I will post more if I learn more.


Snap Chromium browser and profile problems

I accidentally found solution.
I wanted to kill conky process, but i hit chromium in System monitor.
After chromium start with restore previous session, suddenly username and password fill was working!
I checked passwords settings in chromium and everything was present.

So for to restore password sync, it is needed to non-gracefully kill chromium and press restore session button.


Your service provider may have disabled tethering on the device.

You can see if this is the case by downloading one of the tethering apps from the Google Play store and attempting to enable tethering with it.

If you can enable tethering with an "App" but not with the built-in native Android or Samsung software then tethering is disabled by the phone company.


ubuntu 13.10 - language toggle keys don't work

A guess: The problem might be that the combination you select conflicts with a keyboard shortcut used by some other part of the system, e.g. Unity. You may want to try some other combination.


Bluetooth is undergoing changes, so your version is important.
In a terminal (ctrl-alt-t) find the bluetooth version by typing:

bluetoothd --version

The result will be a number like 4.101 for version 4 of bluez or 5.36 for version 5.
Ubuntu 14.04 uses version 4.101, and does have problems keeping a connection with the Microsoft Sculpt Comfort Mouse.  Ubuntu 16.04 alpha uses version 5.36, and works flawlessly, even without the correct oid for my mouse in the gnome-bluetooth pin database.

The basic problem with 14.04 is that the link key is not saved when the mouse is paired, so the connection is not really complete.  The pairing (for version 4) should create a link key in file
/var/lib/bluetooth//linkkeys.  The mouse address is used in the "names" and "trusts" files, but not in the linkkeys file IF IT IS NOT ALREADY PRESENT.   Add the line yourself (even
the example line with an improper hex key), and it should be properly maintained in future pairings.
Example line:

C0:33:5E:01:8A:AC DEADBEEFDEADBEEFDEADBEEFDEADBEEF 4 0

The file is root only rw, so either become root to edit or unprotect, edit, reprotect it.

Version 5 has a totally different location,(/var/lib/bluetooth/<host bt addr>/<mouse address>/info) and way of storing the link and other information, and seems to work with 16.04 (daily).

If that doesn't fix the problem, try adding in file

/etc/udev/rules.d/99-bluetooth.rules

ACTION=="add", SUBSYSTEM=="bluetooth", ATTR{product}=="Microsoft Sculpt Comfort Mouse", ATTR{power/control}="on"


How to disable the authentication prompt from DVD mount and eject (16.04)

Your user does not have access to the correct groups which on a clean Xenial Xerus installation looks like the following on my system:

andrew@athens:~$ groups
andrew adm cdrom sudo dip plugdev lpadmin sambashare vboxsf

You can safely ignore both andrew and vboxfs which relate to my own username and VirtualBox Filesystem membership respectively. You can carefully add your $USER to the required groups in /etc/group using sudo and your favorite commandline text editor or gksudo and your favourite gui text editor...


File system for external hard drive: interoperable and open?

Have you ever tried Exfat?

It's compatible with Windows and OSX, and can be added to Linux by running:

sudo apt-get install exfat-fuse exfat-utils

It's very popular on sd cards etc.

Another option is UDF but I've never used it https://en.wikipedia.org/wiki/Universal_Disk_Format


It's just showing a list of applications that have unread notifications since you locked your desktop.
In this case, Remmina just had a notification for you, perhaps that a remote session had disconnected or something along those lines.

The lock screen means that you can see what is happening while your computer is locked, and it allows you to get a summary of what has been happening while you have been away.
- https://help.ubuntu.com/stable/ubuntu-help/shell-lockscreen.html.en


Guide to particulars in customizing Ubuntu Installer

For a reference preseed, you might like to refer to installation-guide-i386
which contains the following sample preseed:

  /usr/share/doc/installation-guide-i386/example-preseed.txt.gz

  Completely rewrite the packages installed by default, much like minimal installs
  Add a few proprietary applications to the default install list

To provide the list of packages you want installed, you might like to look
for the following line:

  tasksel tasksel/first   multiselect ubuntu-desktop

Where "ubuntu-desktop" can be changed for an arbitrary number of packages
or meta packages.

  Automatically install and mount proprietary drivers on install and live session

Other that specifying the packages needed (for the proprietary drivers), I'm not sure how this would be accomplished. As a side note, you "mount" a partition, you "load" a kernel module/driver.

  Edit the default configuration files for applications installed by default

To make those kind of scripted changes, you probably want to look into:

  d-i preseed/late_command string ...

Where the "..." can be replaced with arbitrary commands like sed -i
for example.

  Specify partitions along with permission

There's a partition section in the example preseed mentioned above.

  Ubiquity with preseed

Casper supports preseed and ubiquity can have many values preseeded. Here are some of the variables that can be preseeded relevant to ubiquity:

ubiquity countrychooser/shortlist select US
ubiquity languagechooser/language-name select English
ubiquity localechooser/supported-locales multiselect en_US.UTF-8
ubiquity ubiquity/summary note
ubiquity ubiquity/reboot boolean true
ubiquity ubiquity/poweroff boolean true
ubiquity ubiquity/success_command string ...

Where "..." would contain the same as the late_command mentioned above, success_command is read by ubiquity and late_command by d-i.


It does sound like you've wiped it, even though you didn't finish the process. DON'T write anything to that disk right now!

Boot from a Ubuntu Live DVD/USB and install testdisk and see if you can recover.

Go here for instructions... http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step (Archived link)


"Some index files failed to download. They have been ignored, or old ones used instead."

You should check your source file config : /etc/apt/sources.list

This website will also help you generate a sources.list : http://repogen.simplylinux.ch/index.php

To better understand what can be the problem check your log files : /var/log/dpkg.log also /var/log/apt


I was able to solve it by creating a file called /etc/X11/xorg.conf.d/20-intel.conf containing the following:

Section "Device"
   Identifier "Intel Graphics"
   Driver     "intel"
   Option     "NoAccel"   "True"
   Option     "DRI"       "False"
EndSection


That looks like a problem with plymouth.
My suggestion:

sudo apt-get install --reinstall  plymouth-themes

and then.

sudo update-initramfs -u


How can I store the value a user enters in a variable?

You can reuse the text property outside the TextField component.

Look at the following example where a Text element shows the result of the Input text + 5:

The corresponding code:

import QtQuick 2.0
import Ubuntu.Components 0.1
import QtQuick.Controls 1.1
import QtQuick.Controls.Styles 1.1

MainView {
    id: main
    width: 300
    height: 150

    Row {
        width: 37;
        height: 19
        spacing: units.gu(3)

        TextField {
            id: q1
            placeholderText: "0"
            font.pixelSize: 12
            text: "0"
            validator: IntValidator{}
            horizontalAlignment: TextInput.AlignHCenter

            style: TextFieldStyle {
                textColor: "black"
                background: Rectangle {
                    width: 45;
                    height: 25;
                    radius: 20.0
                    color: "#F0EBEB"
                    implicitWidth: 40
                    implicitHeight: 24
                    border.color: "#000000"
                    border.width: 1
                }
            }
        }

        Text {
            height: 25;
            text: "TextField + 5 = "+(parseInt(q1.text, 10) + 5)
        }
    }
}

Update:

To store the sum of two text input globally you could define a property in the parent element, look at the following code:

import QtQuick 2.0
import Ubuntu.Components 0.1
import QtQuick.Controls 1.1
import QtQuick.Controls.Styles 1.1

MainView {
    id: main
    width: 300
    height: 300
    property var sum_q1_q2: parseInt(q1.text, 10) + parseInt(q2.text, 10)

    Column {
        width: 37;
        height: 19
        spacing: units.gu(3)

        TextField {
            id: q1
            placeholderText: "0"
            font.pixelSize: 12
            text: "0"
            validator: IntValidator{}
            horizontalAlignment: TextInput.AlignHCenter

            style: TextFieldStyle {
                textColor: "black"
                background: Rectangle {
                    width: 45;
                    height: 25;
                    radius: 20.0
                    color: "#F0EBEB"
                    implicitWidth: 40
                    implicitHeight: 24
                    border.color: "#000000"
                    border.width: 1
                }
            }
        }

        TextField {
            id: q2
            placeholderText: "0"
            font.pixelSize: 12
            text: "0"
            validator: IntValidator{}
            horizontalAlignment: TextInput.AlignHCenter

            style: TextFieldStyle {
                textColor: "black"
                background: Rectangle {
                    width: 45;
                    height: 25;
                    radius: 20.0
                    color: "#F0EBEB"
                    implicitWidth: 40
                    implicitHeight: 24
                    border.color: "#000000"
                    border.width: 1
                }
            }
        }

        Text {
            height: 25;
            text: "Q1 + Q2 = "+main.sum_q1_q2
        }
    }
}

The new Text element now use the property of the "main" component:


There's a metapackage called build-essential which should install the compiler and a bunch of related/needed packages:

sudo apt-get install build-essential

The suggestion to first do sudo apt-get update is sound, this will update package lists and all versions should match nicely.

That is, however, if you didn't modify your /etc/apt/sources.list file manually. If so, then maybe some of the changes you made or repositories you added contain conflicting packages which cause the problems you see. If that's the case, please look at the file and fix the troublesome entries. Of course, if you want help doing so, you can post your sources.list file (or any fragments in /etc/apt/sources.list.d) and maybe someone can help you fix them.


It is as your search result said. If you add any of those accounts in Online Accounts settings, while using GNOME, the gnome-online-miners miners will scan those services for your data, and index it in the local tracker database, so that when you search for data in GNOME shell, those results will appear.


To upgrade a long term support release (LTS) to a newer normal release of the distribution we need to select "Normal releases" in the settings dialogue of Update Manager as shown here:


Google Chrome on Ubuntu 17.04 Runs Extremely Slow

Same here. Both Chrome & FireFox are REALLY slow although DNS responds quickly and ping is good. I have no idea what is going on here but I suspect it has something to do with TCP IPv6.


Use tail -f log.txt | less instead .  On my quick testing, it updates to advance to the new information, and you can then go up or down.  I.e., less updates as an output buffer, not statically referring to the original content.

Or, a slight variation with fewer moving parts (no pipe) -- the solution that Dolphin mentioned in a comment -- less +F log.txt is a nice way to go.  Here's what the man page says for F:

   F      Scroll  forward, and keep trying to read when the end of file is reached.
          Normally this command would be used when already at the end of the  file.
          It  is  a  way to monitor the tail of a file which is growing while it is
          being viewed.  (The behavior is similar to the "tail -f" command.)

In other words, this is perfect for this case.

It does have one problem that prevents it from being my favorite.   An addition like less +F daemon.log | egrep session doesn't work.

One reason I continue to use pipes in my own day-to-day command line work is that, when coupled with history, it's crazy easy to go back, add a pipe, and change the behavior of your command as the data dictates.   If a simple tail -f log isn't working because of the volume of data scrolling off the screen, slap on the pipe to less.  If the volume is too heavy, but you see hints of the lines you're looking for, add a pipe to grep or egrep.  Then chain awk, or sed,  or cut, to get exactly what you want.

This is also a reason that "unnecessary use of cat" is often a ridiculous criticism.  If you cat a file, but find that it is unexpectedly long, use the shell history, hit up-arrow and do something else with it.  Quick fix? Just add cat foo | more.   How long is it?  Up-arrow and | wc.   How many lines are there with "pangloss"?  Add | egrep pangloss | wc .   It's nice if you can start a command knowing exactly where your investigation is going to go, but if you can't, history and pipes are a good way to get things done.   Even if it's ugly, cat file | more | egrep something works fine.


make sure that you can see your default gateway, may be you'd better give us your ifconfig results.


Reaching files from a file server created with Raspberry and Samba

I think you've missed the step of making samba users, which are different to your normal system users. They can be created with the same names and passwords though.

Try the following command for each username:

sudo smbpasswd -a <username>

You'll be prompted for the password twice, like with normal system users.
After you've completed this step, restart samba, and you should be able to access your shares.


Install Sublime (v3) from Webupd8 ppa:

sudo add-apt-repository ppa:webupd8team/sublime-text-3
sudo apt-get update
sudo apt-get install sublime-text-installer

OR

Install Sublime (v2) from Webupd8 ppa:

sudo add-apt-repository ppa:webupd8team/sublime-text-2
sudo apt-get update
sudo apt-get install sublime-text

Just tried out these ppas. Everything works fine.


So you're booting to Windows, mounting an .iso then using that .iso to install Ubuntu on top of the Windows you're currently running? That's never gonna work.

What you need to do is install the .iso to a USB drive in a way that makes it bootable. Google unetbootin, find it, download it, and use it to create that bootable USB.

Then change your BIOS settings to boot from that USB. Then you're going to make some choices. First, do you want to wipe Windows and make this an Ubuntu only machine, or do you want to dual-boot so you can use either? Answer that question before you install Ubuntu.

And for god's sake, back up everything you don't want to lose first!


How to know if a package is graphical or command line application?

For installed application your can follow my other answer.

In any case the locations of files (executables, man-pages and other stuff) should conform Filesystem Hierarchy Standard as a rule.

For not installed application we can adapt aforementioned method but we will use apt-file command instead of dpkg.

So we will do the following:

Install apt-file:

sudo apt-get install apt-file

Update apt-file cache:

sudo apt-file update

List all package files with apt-file list (see man apt-file for details) and find files in /bin, /sbin, /usr/bin, /usr/sbin, /usr/games directories. So we can use the following command:

$ sudo apt-file list httpcode | grep -E "/bin/|/sbin/|/usr/games/"
httpcode: /usr/bin/hc

So we can see that in this example /usr/bin/hc belongs to the package.
List all man-pages:

$ sudo apt-file list httpcode | grep "/man/"
httpcode: /usr/share/man/man1/hc.1.gz

So we can see that we can use man hc.
For applications with GUI I run search for *.desktop files:

$ sudo apt-file list httpcode | grep ".desktop"
$

In this particular case it will not return anything.

But in case of real GUI application such as GNOME Terminal we will try to find its *.desktop file

$ sudo apt-file list gnome-terminal | grep ".desktop$"
gnome-terminal: /usr/share/applications/gnome-terminal.desktop

And we see that it is found, so it is a GUI application.
Also we can check first level of reverse dependencies with command like

$ apt-cache rdepends gnome-terminal | grep desktop
ubuntu-gnome-desktop
ubuntu-desktop
ubuntukylin-desktop
ubuntu-gnome-desktop
cinnamon-desktop-environment
ubuntu-desktop

- so GNOME Terminal needs DE which is usually ran on Xorg.

Also for not installed package one can visit https://packages.ubuntu.com and use Search package directories here (for all releases or for selected release), then click on list of files link in the right column of the table:

and one will get the file list:

This list may interpreted manually or by using searchbar in the browser.


"Is there a FAQ site?"

AskUbuntu is a Question and Answer site for the Ubuntu operating system.

Would you like to see a list of Frequently Asked Questions?

Simply click "Questions" and you can sort by frequency under the "more" category.

You can also Search on AskUbuntu to find questions about a specific topic.


Alt + Tab is not working in gnome shell at ubuntu 12.04

Search the Ubuntu Software Center for "CompizConfig" or
sudo apt-get install compizconfig-settings-manager
Launch CompizConfig Settings Manager by pressing Alt+F2 and running ccsm. (This may also be run from a Terminal.)
Click "Window Management"
Enable either "Application Switcher" or "Static Application Switcher"

Lance's graphical guide: http://i.imgur.com/8LzO2.png

Edit: My answer sucked, but it was the only one. However, Lance's comment was helpful to many, so I changed my answer for future searchers.


Well, if you have one workspace only, you can install brightside. If you are in Bionic you won't find it in repositories.
I test it in Ubuntu Bionic (18.04) with the xenial (16.04) and worked so you can download directly from the previous link.

More info: Is it possible to remove mouse pointer bounds (i.e. wrap the screen)?


X thinks I have a built-in display but I don't

Here's how I got around this.

From the xrandr output get the name of the troublesome ghost screen. In my case (see question) it is eDP-1, but others might have LVDS-1 or something.

Append this kernel param (credit to this superuser answer):

video=eDP-1:d

The :d means disable this, even if something is plugged in.

And now it works. For completeness' sake, to append a kernel param once you can do a reboot, wait till you see the blank grey screen and hit Escape which should hopefully then show you a GRUB menu. Press e to edit the ubuntu entry, move the cursor to the end of the line that starts with linux ... and add the above (there should be  a space before it). I suggest you try parameters this way first - otherwise you could end up with an unbootable system if you get it wrong.

To make this stick, once you've found something that works, edit /etc/default/grub and look for the GRUB_CMDLINE_LINUX_DEFAULT line and add your parameter within the quotes like so:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video=eDP-1:d"

Then run sudo update-grub.


Getting error in compiling install.sh of a wireless driver

Please get a temporary working internet connection by ethernet, tethering or any means possible. Open a terminal and do:

sudo apt update
sudo apt install build-essential git dkms linux-headers-generic
git clone https://github.com/kelebek333/rtl8188fu
cd rtl8188fu
sudo dpkg -i rtl*.deb

The process dpkg will take a few moments, please be patient. Next, do:

sudo modprobe rtl8188fu

Your wireless should be working.


How can I make a write protected Ubuntu installation?

I have been running a Full installation of Ubuntu from a flash drive for close to ten years now with no problems.

Most good flash drives have wear leveling and are good for at least 10000 writes.
For a 64GB flash drive lets do the math:

(64000 MB x 10000 writes) / (50 MB/s x 28000 s/8hourday) = 457 work days absolute minimum life span.


Why does my system boot into a tty virtual terminal after installing 12.04?

Since I am assuming you might have got an upgrade, so there must be a problem with Xauthority file in /home folder.
Try logging in by pressing Alt+Ctrl+F1 and delete any instance of the Xauthority files found. Following command can do it-

sudo rm .Xauthority*

Otherwise, enter the command to get gnome session to open:

startx gnome-session-fallback -- :1


Script to change terminal shortcut to open in fullscreen

EDIT 2017-05-01:

The OP changed the wording of the question. To better address his concerns, I am making an addition to the top of my post and leaving the original answer below.

Here is a script to automate the process of creating a launcher on the Unity Launcher to open a full-screen session of gnome-terminal. It must be run as the user for whom the launcher should be added. I cannot be run with sudo!

#!/bin/bash
# This script automates the process of creating a desktop launcher to open a
# full-screen terminal and then adds that launcher to the Unity Launcher

# Change this path if you want to drop the desktop launcher somewhere else
# Note that the user must have full permissions on the path
launcherPath="$HOME/fst.desktop"

# This is the launcher file
launcher="#!/usr/bin/env xdg-open

[Desktop Entry]
Version=1.0
Type=Application
Terminal=false
Exec=gnome-terminal --window --full-screen
Name=Full Window Terminal
Comment=comment here
Icon=gnome-terminal"

# Save the launcher and make it executable
echo "$launcher" > "$launcherPath"
chmod +x "$launcherPath"

# Default Unity Launcher favorites
#    ['application://ubiquity.desktop', \
#   'application://org.gnome.Nautilus.desktop', \
#   'application://firefox.desktop', \
#   'application://libreoffice-writer.desktop', \
#   'application://libreoffice-calc.desktop', \
#   'application://libreoffice-impress.desktop', \
#   'application://org.gnome.Software.desktop', \
#   'application://ubuntu-amazon-default.desktop', \
#   'application://unity-control-center.desktop', \
#   'unity://running-apps', \
#   'unity://expo-icon', \
#   'unity://devices']

# You can add or remove items from this list as you see fit. For example,
# removing the line for `*ubuntu-amazon*` will remove the amazon launcher
favorites="['application://ubiquity.desktop', \
'application://org.gnome.Nautilus.desktop', \
'application://firefox.desktop', \
'application://libreoffice-writer.desktop', \
'application://libreoffice-calc.desktop', \
'application://libreoffice-impress.desktop', \
'application://org.gnome.Software.desktop', \
'application://ubuntu-amazon-default.desktop', \
'application://unity-control-center.desktop', \
'unity://running-apps', \
'application://$launcherPath', \
'unity://expo-icon', \
'unity://devices']"

gsettings set com.canonical.Unity.Launcher favorites "$favorites"

Once this script is saved in a file and made executable, running it with a regular user account will drop the launcher on the Unity Launcher.

Launcher that can be pinned to Unity Launcher

If you want a launcher that you can pin, create a file named something .desktop like full-screen-terminal.desktop with the following contents...

#!/usr/bin/env xdg-open

[Desktop Entry]
Version=1.0
Type=Application
Terminal=false
Exec=gnome-terminal --window --full-screen
Name=Full Window Terminal
Comment=comment here
Icon=gnome-terminal

Save this file and make it executable. Double-click it to run. Alt+Tab to switch apps so you can see the Unity Launcher. Now you can pin the running full-screen terminal "app" in the Unity Launcher.


I am trying to update the apt source I am getting the following error how to fix it

So you may have upgraded your OS or the support for it has ended and that is the problem. Those repositories don't support your OS version.
The repositories are still available on http://old-releases.ubuntu.com/ubuntu. You can change them in /etc/apt/sources.list, replacing all occurences of http://us.archive.ubuntu.com with http://old-releases.ubuntu.com.

you can open sources.list via the terminal with sudo nano etc/apt/sources.list

Another way to fix the problem:

Open "Software & Updates"
Click "Other Software"
Choose a repository you get an error from and remove the checkbox
Do the same with the repos you get other errors as well


How can I redownload previously purchased Linux Format magazine on Ubuntu Software Center?

Answering my own question. I applied the method described in this answer

Reinstall commercial software (e.g. oil rush, steelstorm etc.)

And it worked!!


Fix Ubuntu 14.04 installation with Live USB drive

Solved!! This question: Can I add a proprietary wireless driver to a liveUSB stick? basically answers it. The user daffydack said that the driver IS ACTUALLY ON THE INSTALLATION MEDIUM. So I reinstalled a few times and with a few different versions and still couldn't get wireless... but the last time I interrupted an installation causing it to go to the live cd / test phase. Then I looked at the additional drivers thing and still couldn't get them. Then I closed it and opened it. Then like a few minutes later it just popped up. So I installed the drivers and attempted to install the os assuming the changes to the live environment would carry over. Then it wouldn't install the os. Then I cancelled that and did some googling. Then in one last ditch effort tried the install again. And here I am in a fresh new install. Btw if someone reads this please tell me, is it always such a pain in the butt trying to install ubuntu or am I just cursed? I always have problems. You would think with the amount of development that has gone into other areas of this project that the foundations (booting installing etc) would be pretty solid... :s


Can't get .iso creation tools working in 18.04

This is a known issue.
Please go for this command

$sudo QT_X11_NO_MITSHM=1 unetbootin

If it does not work, then first uninstall your current version of unetbootin, then use official unetbootin page to install using ppa instead of deb files. If fails then try opening it from launcher instead of terminal.


One liner ffmpeg (or other) to get only resolution?

Using ffprobe from the ffmpeg package:
ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=s=x:p=0 input.mp4

Example result:
1280x720

What these options do:

-v error makes the output less verbose.
-select_streams v:0 selects only the first video stream.
-show_entries stream=width,height chooses only width and height from the big list of parameters that ffprobe can provide.
-of csv=s=x:p=0 formats the text output. The csv formatting type is used because it makes a simple output. s=x makes it use an x to separate the width and height values. p=0 makes it omit the stream prefix in the output.

See the ffprobe documentation and FFmpeg Wiki: ffprobe tips for more info.


Force overwrite

sudo dpkg -i --force-overwrite <archive_path>

Finish installing

sudo apt -f install

If you still have problems then execute whatever commands it presents to you afterwards.


GUI for running network statistics or bandwidth limiter?

Traffic shaping on Linux system used to require knowledge of lot of things like iptables, qdiscs & networking protocols. Things have changed and now there are couple of tools which handle all of this complexity without requiring much knowledge. And one of them is wondershaper.

First install wondershaper by issuing following command.

sudo apt-get -y install wondershaper

Use following command template to make it work right away.

sudo wondershaper <interface name> <down speed> <up speed>

Where interface name is your network interface name like eth0 or eth1 or wifi0 and down speed , up speed are self explanatory and specified in kilo bits per second.

So sample command will look like

sudo wondershaper eth0 512 512

To disable wondershaper from controlling particular interface use following command.

sudo wondershaper clear <interface name>

To make these changes permanent add following lines to /etc/network/interfaces under relevant interface section.

up /sbin/wondershaper <interface name> <downspeed> <upspeed>

down /sbin/wondershaper clear <interface name>

Thats it.

Install Darkstat in Ubuntu to analyze network traffic.


How to download all the vidoes in a youtube playlist in linux?

Updated answer:

Use command below to download playlist:

youtube-dl -i -o (location) http://www.youtube.com/playlist?list=XXXXXXXXXXX

where

-o, --output TEMPLATE   Output filename template, see the "OUTPUT TEMPLATE"
-i, --ignore-errors              Continue on download errors, for example to
                                 skip unavailable videos in a playlist

See Output Template

Example:

$ youtube-dl --get-filename -o '%(title)s.%(ext)s' BaW_jenozKc
youtube-dl test video ''_ä↭.mp4    # All kinds of weird characters

$ youtube-dl --get-filename -o '%(title)s.%(ext)s' BaW_jenozKc --restrict-filenames
youtube-dl_test_video_.mp4          # A simple file name

# Download YouTube playlist videos in separate directory indexed by video order in a playlist
$ youtube-dl -o '%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s' https://www.youtube.com/playlist?list=PLwiyx1dc3P2JR9N8gQaQN_BCvlSlap7re

# Download all playlists of YouTube channel/user keeping each playlist in separate directory:
$ youtube-dl -o '%(uploader)s/%(playlist)s/%(playlist_index)s - %(title)s.%(ext)s' https://www.youtube.com/user/TheLinuxFoundation/playlists

# Download Udemy course keeping each chapter in separate directory under MyVideos directory in your home
$ youtube-dl -u user -p password -o '~/MyVideos/%(playlist)s/%(chapter_number)s - %(chapter)s/%(title)s.%(ext)s' https://www.udemy.com/java-tutorial/

# Download entire series season keeping each series and each season in separate directory under C:/MyVideos
$ youtube-dl -o "C:/MyVideos/%(series)s/%(season_number)s - %(season)s/%(episode_number)s - %(episode)s.%(ext)s" http://videomore.ru/kino_v_detalayah/5_sezon/367617

# Stream the video being downloaded to stdout
$ youtube-dl -o - BaW_jenozKc

By default youtube-dl tries to download the best quality, but sometimes you may want to download other format so use command :

youtube-dl -i -o (location) -f mp4 http://www.youtube.com/playlist?list=XXXXXXXXXXX

Note:

You will find Options -citk or -citw in old answers that is not needed now . Please see youtube-dl FAQs.

References:

youtube-dl
phihag's Answer


Lenovo Thinkpad E480 No screen or Post - Fresh Install 18.04

The most aggressive solution is to open the laptop and remove the bios battery for 10-15 seconds
This will reset the bios state


View the 'terminal name' of an installed app?

Application binaries usually installed into /bin or /usr/bin folders.
You could use ls /bin or ls /usr/bin to list all binaries to console commands and desktop applications.

Also, if you have your Firefox running, you could use ps aux | grep firefox command to see what binary path have been used for application.

For example:

$ ps aux | grep chrome
user   11182  0.0  0.6 4568428 54112 ?       SNl  13:48   0:00 /opt/google/chrome/chrome --type=renderer --disable-webrtc-apm-in-audio-service --field-trial-handle=7356609730568785120,9558563176934852878,131072 --lang=en-US --enable-crash-reporter=181c2763-8134-47a2-bc44-349a4e81270e, --disable-client-side-phishing-detection --enable-auto-reload --num-raster-threads=1 --renderer-client-id=16 --no-v8-untrusted-code-mitigations --shared-files

It shows that chrome binary is located in /opt/google/chrome/ folder. So another location you could check is /opt: ls /opt.

Console commands for applications usually named starting with lower case letters.


Desktop not showing well using vncserver on ubuntu 15.10

Simply start vncserver with the command:

/usr/bin/vncserver -geometry 1024x768 -depth 24 :0

geometry: define the resolution
depth: define color depth

If you want to automatically start it at boot, add it into /etc/rc.local

sudo cat "/usr/bin/vncserver -geometry 1024x768 -depth 24 :0" >> /etc/rc.local


tl;dr: Try using gksudo instead.
Explanation
gksu makes you enter the root password. By default, Ubuntu does not have a password for the root user. gksudo makes you enter the password for an ordinary user that happens to have superuser privileges.


Can you install ubuntu on xp and then uninstall xp? how?

First of all use the live CD to boot into an UBUNTU live session (do not install). Then you can save all your music and ebooks as you can access the windows partition. If you now want to install UBUNTU you can choose to use the whole disk for the install thus windows will be deleted and UBUNTU installed.


Can't upgrade from Ubuntu 14.04 to 16.04 - dependency issue

Apt is one of the package management engines in Ubuntu. When you run the upgrade, versus just overwriting everything with a clean install, it downloads and unpacks the new packages over the old ones.

This warning appeared because either apt's integrity (checksum and signature) couldn't be verified or you are using an older version (the most recent one for 14.04 is 1.0.1ubuntu2.15, 16.04 uses 1.2.15).

Check which version you are using by typing

sudo dpkg -l apt

Into the terminal. If you are using an version lower than the one listed in your error message, you will need to run a full upgrade by running

sudo apt-get update

then

sudo apt-get upgrade


fresh lubuntu install & wireless problems

Check to see if the OS detected the device and perhaps your just missing a driver

$ sudo lspci

The output you see from lspci should have a line somewhere that looks somewhat like this if its been detected

-->  Intel Corporation PRO/Wireless 2200BG......

You can also look at the dmesg logs for potential clues that can provide hints

$ sudo dmesg | grep Intel

Run modprobe ipw2200 to see if you have the needed driver as part of your intallation

$ sudo modprobe ipw2200


Need to create NTFS partition on my hard drive but mount point "/" is stopping me

Basically, you cannot unmount the root partition while you are using it. You will have to shut down your system and boot from another media like a USB stick or a CD and get into live mode to modify partitions on your HDD.

From my experience the best solution for this kind of problem - if you need to run some Windows program alongside Linux - is to use a virtual machine and Windows install there . It is much safer and easier.

Here, I suggest you to install Oracle VirtualBox. It's a well known multi-platform Virtual Machine program.


How to shorten your command line prompt (bash) like Spatry does it?

Assuming you're using bash, place a line like:

PS1="----[\u@\H]------[\t]----\w\n==> "

into your ~/.bashrc file, which will set your bash prompt to what you want. If you want to change it further, just consult the page http://www.cyberciti.biz/tips/howto-linux-unix-bash-shell-setup-prompt.html


You're logging in as a user who has sudo rights thus being able to get root for a command.

You're not root. root has no password on Ubuntu and one can't log in as root by default.


Ubuntu Server 16.04: benchmarking disks from terminal

bonnie++ will do benchmarks, with many options for how to perform them.

It can be installed with sudo apt install bonnie++


Does Ubuntu 13.04 have a desktop environment built-in?

What you installed is the -server- version of Ubuntu. That one does not come with a desktop but you can add software onto it (like a desktop) as instructed in that link you posted. It is common to have the server version on a webhost since most only want to use SQL and a webserver (and those do not require a desktop).

If you install the -desktop- version all the things you installed manually would have installed as well (ie. ubuntu-desktop).

VNC is separate though; you still need to install this yourself.


Extracting a specific string after a given string from HTML file using a bash script

I can't sensibly advise doing this, because parsing html with regex is not likely to end well but you might be able to get the string MANIKA with
sed -nr '/MOM:/ s/.*MOM:([^"]+).*/\1/p' file

It works OK on your sample anyway...
Notes

-n don't print anything until we ask for it
-r use ERE
/string/ find lines with string
s/old/new/ replace old with new
.* any number of any characters
([^"]+) save some characters that are not "
\1 backreference to saved characters
p print just the lines we changed


I wrecked my server: best way to move forward?

So after some discussion in chat...

First problem was that /var/run/mysql did not exist. This explains the error message

#2002 - No such file or directory
The server is not responding (or the local server's socket is not correctly configured).

as this socket is located in /var/run/mysql/.

Next problem was that the user table was corrupt, so when starting with sudo -u mysql mysqld --skip-grant-tables to start without authentication, mysql did not want to update the user table:

ERROR 1728 (HY000): Cannot load from mysql.user. The table is probably corrupted

As user had backup of database content, the easiest option at this point was to simply remove all database files, with sudo rm -Rf /var/lib/mysql/, and reinstall mysql-server. This ensured that mysql recreated the user table upon installation.


squid-deb-proxy on client side unable to get packages from the server

You can't just copy debs into the squid-deb-proxy directory as those are stored as squid objects, so that probably won't work.

How to add packages to a squid-deb-proxy cache?

Unfortunately I don't think there's a way you can do this unless you would have install squid-deb-proxy server and client on your laptop before it was upgraded, so it could have cached the debs prior to the upgrade on the first laptop.


Raise keyboard layout change window/notification upon left Alt+Shift?

Those are two ways to do it. You should probably first disable the Left Alt+Shift shortcut the way you activated it (assuming you used Tweaks).

Next go to Settings -> Devices -> Keyboard -> Typing. From there you can change the shortcuts for the built-in way to do it - with the overlay - rather than adding a new shortcut.


Prevent laptop from going to suspend mode

find system settings, (in Unity, just start typing the word "system")

look for "Brightness and Lock".  set this ==> "Turn Screen off when inactive for:"
to "Never".


I recommend Ubuntu 16.04 instead of 18.04 for your Sandy Bridge processor. If you would still like to use Ubuntu 18.04 there are steps you can take to make it faster. From this answer Make Ubuntu 18.04 lighter?:

Disable or Uninstall Extensions
Turn Off Search Sources
Disable File Indexing
Turn Off Animations
Install Lighter Alternative Apps
Limit Startup Applications


Display all the files with read and write permissions and display result in a file

You can just use the find command.

find /path/to/where/to/search -type f -perm -666

Enter path where you want to do the search. The -type f meand that only files will be searched. Finally -perm 666 means that only files with read/write permissions for all users will be matched. Please note that if file has also executable permission for any user it will not be matched. Than you just redirect the output to a file:

find /path/to/where/to/search -type f -perm -666 > LogFile.txt

Read man pages for find to learn more and to realy match the permissions for users/grup you really need.


hgsubversion doesn't find python bindings

On HgSubversion wiki you can read :

  The easiest way to install hgsubversion is to just clone the
  hgsubversion repository and then configure Mercurial to use it.
  Cloning the tip is recommended as it is much more stable than the latest tag 1.2.1 from march 2011.

Clone the repository :

$ hg clone http://bitbucket.org/durin42/hgsubversion/ hgsubversion

All tests passed :

$ nosetests
Ran 493 tests in 1400.680s

OK

Check that HgSubversion is installed and properly activated :

$ hg version --svn
Mercurial Distributed SCM (version 1.9.1)
(see http://mercurial.selenic.com for more information)

Copyright (C) 2005-2011 Matt Mackall and others
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

hgsubversion: 3292ff0380f3
Subversion: 1.6.12
bindings: Subvertpy 0.8.3


Can not install steam: E: Unable to locate package

Steam is in multiverse repository, so you have to enable it before installing steam.

Open Software center, navigate to the "Ubuntu software" tab at the top, select (check off) multiverse.

Use the "Reload" button to update your package list.

Now, install with sudo apt-get install steam.


How to run command as another user or keep file attributes?

Putting sudo username before your command will solve your problem.


Windows 7 dual boot, tried installing ubuntu on top of another ubuntu installation

First of all, back up all your data using the ubuntu live cd.
Next, get back your windows bootloader using these instructions.
Then, put in the live cd and during installation of ubuntu 14.04 don't do erase ubuntu and reinstall, instead, go to manual partitioning(or whatever similar is written there) and erase the partition where ubuntu was installed previously(you can find it by seeing the partition type as ext4 or ext3). Completely format it and install ubuntu there by selecting it and then clicking on details or change button for that partiton(where you should click on tick mark for "format?" and then select"/" in mount point).
That should solve your issue!


Unity is a Canonical product. Canonical controls both Ubuntu and Unity.

UPDATE (after tumbleweed's comment):

"Canonical controls Ubuntu" (1) vs. "Canonical does not control Ubuntu development" (2).

Well, truth(tm) is probably somewhere in the middle. It's worth to mention about the Ubuntu Fundation which was founded by Mark to make Ubuntu more Canonical independent.

Anyhow, Ubuntu will probably never be as community controlled as Debian is,
but I don't think it's bad. I think what Mark and Canonical do is really good.
IMHO, Mark should get a Nobel prize for his attitude and accomplishments for the human race.


"Trying Ubuntu" Can't install programs! Help!

For most applications:
Click on the Ubuntu Software Center icon (see below) to install applications. You should rarely, if ever, download software directly from the internet, with Google Chrome being the notable exception. The main reasons for using software from the software-center are stability, security, and compatibility, since it has programs that are built specifically for Ubuntu.

For Google Chrome: You need to download the .deb file from the Chrome website [64 bit .deb (for Debian/Ubuntu)]. It will end up in your Downloads folder. Open Files (Nautilus), go to Downloads, and double-click the .deb file. It will open Ubuntu Software Center and install your program.


How to get back the Ubuntu 14.10 default login screen

you can easily do it by following steps

type the following code in the terminal to reconfigure lightdm

sudo dpkg-reconfigure lightdm

then a dialog box appears to asking to choose the default login manager

lightdm or kdm i guess, after that restart the lightdm by typing

sudo lightdm restart

or you can do it by the following way

edit the /usr/share/lightdm/lightdm.conf.d file by

pressing ctrl+alt+t and typing

sudo nano /usr/share/lightdm/lightdm.conf.d

and add the following line

    [SeatDefaults]

    greeter-session=unity-greeter

save the file pressing ctrl+x and type y and restart lightdm


What did I do to make Ubuntu fail to attempt to connect to one specific IP address?

The short answer was I had chosen the wrong gateway on that machine. Near as I can tell, this was the order of events:

Computer was setup using DHCP, no problems.
I edited /etc/network/interfaces to give that machine a static IP. No problems, right gateway.
At some point after this, probably a few weeks, for some reason I used a GUI thing to mess around with networking settings. At this point, I mistakenly changed my gateway settings to the wrong router.

This is where it got weird. Either the computer or the wrong router had some sort of partial routing table or something, causing the initial problem.

The key command which ultimately sorted this for me:

route -n

When learning about ip tables and that sort of thing, I came across that command. I ran it and saw the gateway was the wrong router. I checked /etc/network/interfaces which no longer had my static block in it.

I put that back in there with the correct router's IP address and everything works.


The program itself seems to be made in .NET. So it won't open using Wine.

You may be able to open it using Mono (install the Windows version of Mono with Wine).


How to log out from the GUI in Ubuntu 18.04 without pressing a keyboard shortcut?

Click the power button ⏻ in the panel in the upper right corner of the Ubuntu desktop.
Click your username in the dropdown menu that appears below the power button to unfold its menu options.
Click Log Out which is marked by the mouse cursor in the below screenshot. Another way of doing the same thing is to install the Log Out Button GNOME Shell Extension in Ubuntu Software which adds a Logout icon that is shown in the lower right corner of the screenshot to the right of the Power Off ⏻ icon.


How do I open an app in a certain workspace from terminal?

It's a hacky workaround, but I think this would achieve what you're looking for. You need to install wmctrl first by running the following command

sudo apt install wmctrl

Then you need to create a bash script. First create a text file and add the following lines to it.

#!/bin/bash
wmctrl -s 1
google-chrome --new-window https://askubuntu.com/ --profile-directory="Person 0"

(note that you need to use wmctrl -s %n in the second line if you want to open Chrome in the %n+1-th workspace). Save the file as, say chrome-workspace2.sh, and make it executable.

Finally, while creating the keyboard shortcut, use the full path to this script as the command for the shortcut.


WSL2 / Ubuntu 20.04 (Windows build 2004) (bootcamp) setup fails with errr code 0x80370102

The answer to this problem comes in 2 parts. Most macs support virtualisation, but you need to find out how to check this. I found this issue on stackoverflow How to enable support of CPU virtualization on Macbook Pro?. From a macOS terminal, you need to run this command:

sysctl -a | grep machdep.cpu.features

This returns something like:

machdep.cpu.features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX SMX EST TM2 SSSE3 FMA CX16 TPR PDCM SSE4.1 SSE4.2 x2APIC MOVBE POPCNT AES PCID XSAVE OSXSAVE SEGLIM64 TSCTMR AVX1.0 RDRAND F16C

If the string returned contains "VMX", then Virtualisation is supported.
Now, you need to ensure that virtualisation is enabled from the macOS side. Open up system settings then go to Start Up disk. Now just looking at the current setting may show that your windows partition is set as the start up disk. You need to explicitly go in and set it to windows, so unlock the padlock and click on your windows partition. The act of doing so activates other settings including enabling virtualisation. When I first encountered this issue, I could already see that my windows partition was visibile in the list of disks to selected as the startup disk and I probably thought no more of it, not realising you have to set it to windows explicitly.
After I did this then rebooted into windows, then open "Programs and Features" (run appwiz.cpl), then select "Turn windows features on or off", look at the options and ensure that "Hyper V" is not a disabled greyed out option. Select "Hyper V", then enable "Windows subsystem for linux". You should now be able to proceed with WSL2 without seeing errors pertaining to virtualisation not being enabled.


Yes, jobs-admin is the new GUI which uses jobservice to configure Upstart scripts.  It's in Maverick's repos, but there's a PPA available at https://launchpad.net/~jpeddicord/+archive/jobtools for Lucid.


I had the same problem and solve change the skype version to last version that time: 4.2.0.13-1_i386.deb , in fact by repository is more precise but I guess that have a error in any list of repo.
 Unfortunately  now have other problem with the sound, a noise in line, maybe the pulse audio, so... I wait answers too ;)