Know if you are the only one using your PC

First of all Linux did not come from Minix, and Minix is not based on Unix. Minix is a Unix-like operating system. So is Linux. They have independent code bases.

You can check who's logged in with w in a terminal:

$ w
 11:15:32 up 3 days, 14:07,  4 users,  load average: 0.40, 0.64, 0.75
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
vidarlo  pts/0    :0               Sat21   49:08   4.45s  4.40s alpine
vidarlo  pts/1    :0               Sat21    0.00s  0.10s  0.00s w
vidarlo  pts/2    :0               Sat21    1:17m 54.29s 54.25s mosh-client eli
vidarlo  pts/3    :0               Sat21   26:52   0.26s  0.03s ssh nina

Note that my own account shows up multiple times, but all are from :0, which is the first X server.

If I run this on a box with more users logged in, it will produce a different output:

[~]$ w
 11:16:32 up 17 days,  1:58, 12 users,  load average: 0.24, 0.27, 0.27
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
a        pts/1    95:S.0           18Feb18  1:18m  2:39   2:39  irssi -c freeno
b        pts/2    80:S.0           18Feb18  1:12   2:13   2:13  irssi
a        pts/4    95:S.3           Sun20    2days  0.03s  0.03s /bin/bash
a        pts/5    95:S.2           18Feb18  2days  0.03s  0.01s /bin/bash
c        pts/0    217:S.0          28Feb18 22:36m 47.15s 47.12s irssi
d        pts/6    62.101.nnn.nn    Mon15   43:28m  0.07s  0.07s -bash
e        pts/7    193.157.nnn.nn-  09:03    1:12   0.43s  0.39s screen -r
c        pts/8    217.140.nn.nnn-  Tue17   22:36m  1.01s  0.95s screen
a        pts/9    95.34.nnn.nn-    07:57    0.00s  0.54s  0.51s screen -x
a        pts/11   95:S.4           Mon19   39:24m  0.00s  0.00s /bin/bash
a        pts/3    95:S.1           Sat22    3days  0.13s  0.00s /bin/bash
a        pts/12   95:S.5           11:16    0.00s  0.00s  0.00s w

I've redacted the usernames and IP's to conserve some privacy, but the IP-addresses indicates they're logged on remotely.

Note that malware and backdoors will not necessarily show up in w, as they may attempt to hide. In general, Ubuntu has a fairly sane setup, with no insecure services listening for remote connections. If you in addition keep your system up to date, and use good passwords, only users you give access will have access.

But multiple users may indeed use the same computer, without noticing each other to any degree.


Hamster Shell Extension

Category: Productivity

Clean gnome shell extension for hamster.


From the screenshot you sent, I see  that you dont have Network Manager ( nmcli ) installed.
I am suggesting you install that, get info on the interfaces you have present and create a working network connection.
Follow the steps below ...
: Update Package List:
sudo apt update

: Install Network Manager :
sudo apt install network-manager

: Enable Network Manager :
sudo systemctl enable NetworkManager.service

: Start Network Manager :
sudo systemctl start NetworkManager.service

: Ascertain the detected interfaces :
sudo nmcli device status

: Create A Network Connection - Based on devices you noted above ,say eth0 :
sudo nmcli connection add type ethernet con-name some_name_you_like ifname eth0 ip4 10.10.10.10/24 gw4 10.10.10.1

: Check your DNS Settings :
sudo nmcli connection show "the_name_from_above" | grep ipv4.dns

: Add Quad9 DNS :
sudo nmcli connection modify "the_name_from_above" ipv4.dns "9.9.9.9"

: Test :
sudo nmcli connection show "the_name_from_above" | grep ipv4.dns
ping askubuntu.com


TTY console on one monitor, X/Wayland on another

This is certainly not a definitive answer, as in most cases of an answer for the negative.
I think what you mean to accomplish is likely not possible, as all of the solutions for booting into text mode do so at the grub level.
I hardly see a way that grub tells the OS to perform your intended actions.
Sources:

How to boot to text only mode? Problem with laptop with Nvidia GPU
https://dannyda.com/2019/06/19/turn-off-display-automatically-on-ubuntu-18-04-server-with-text-boot/
https://unix.stackexchange.com/questions/17027/how-to-set-the-resolution-in-text-consoles-troubleshoot-when-any-vga-fail (very old)
https://www.linuxuprising.com/2020/01/how-to-boot-to-console-text-mode-in.html

(Possibly) Related, and perhaps helping in finding a workaround, YMMV:

Dual Monitor Setup : Grub loader goes to HDTV even if it is turned off
Forcing grub menu to external monitor connected to laptop via HDMI/VGA
https://help.ubuntu.com/community/MultiseatOneCard
https://unix.stackexchange.com/questions/13619/how-do-i-prevent-xorg-using-my-linux-laptops-display-panel
https://wiki.archlinux.org/index.php/Multihead
https://wiki.archlinux.org/index.php/Extreme_Multihead


How can I create an EFI partition on my USB drive?

You can use GParted for this task (create an EFI partition) ... to install it open a terminal and execute :

sudo apt install gparted

Open GParted from the Dash, select the USB drive, create a new gpt partition table and then create some new partitions. Here is a presentation I made how to do it -> How to prepare a disk with GParted


To your first question:
Yes, you should partition your drive. At least a small partition for swap space - rule of thumb: 2 times your real RAM - should be made, at least for hibernation this is recommended.
Select linux/swap as partition type.
For a desktop system, this might be enough, but a seperate /home partition is often seen. It might be handsome for backup images.
2nd and 3rd Question:
You don't need to download drivers. Drivers are included in the kernel. But you shouldn't, as an unexperienced user, install a beta version. You may install 11.10 and upgrade in April easily.


chrome exit shortcut ctrl shift q not working

Disabling the shortcut was requested in Chromium bugs, and it looks like the request was finally fulfilled:

https://bugs.chromium.org/p/chromium/issues/detail?id=243164

You can join those that are now requesting it as a customization flag. Otherwise, looks like you'll have to make a custom shortcut.


fixed it by opening /etc/shells and adding the following line at the end

/usr/sbin/nologin


Something very similar is happening with Scilab 6.1.0.0 on Ubuntu 20.04 as well!
However, in my case, Scilab does not start at all!
Really need to get Scilab up and working ASAP!
Here's my log:
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.scilab.modules.jvm.LibraryPath (file:/usr/share/scilab/modules/jvm/jar/org.scilab.modules.jvm.jar) to field java.lang.ClassLoader.sys_paths
WARNING: Please consider reporting this to the maintainers of org.scilab.modules.jvm.LibraryPath
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Could not access to the Main Scilab Class:
Exception in thread "main" java.lang.ExceptionInInitializerError
    at org.scilab.modules.localization.Messages.gettext(Unknown Source)
    at org.scilab.modules.commons.xml.XConfiguration.<clinit>(Unknown Source)
    at org.scilab.modules.core.Scilab.<clinit>(Unknown Source)
Caused by: java.lang.NullPointerException
    at java.base/java.lang.ClassLoader.loadLibrary(ClassLoader.java:2646)
    at java.base/java.lang.Runtime.loadLibrary0(Runtime.java:830)
    at java.base/java.lang.System.loadLibrary(System.java:1873)
    at org.scilab.modules.localization.MessagesJNI.<clinit>(Unknown Source)
    ... 3 more

Scilab cannot create Scilab Java Main-Class (we have not been able to find the main Scilab class. Check if the Scilab and thirdparty packages are available).

Would be really great if someone could help resolve this!


What is the name of the default, preinstalled, PDF viewer on Ubuntu?

Evince (on my version, ubuntu GNOME 14.04, at least)


Can't open image files with Picasa in Ubuntu 12.04

Open Picasa and go to
Tools > Options > File type
Check the boxes next to all the file types and click OK


I don't know whether this will do it but you could try, in a terminal:

sudo apt-get autoremove

It should not do any harm.


Please do:

sudo apt-get remove --purge bcmwl-kernel-source
sudo modprobe brcmsmac

now your wireless should be working unless you have tried another driver besides the wl if it stops working after a reboot then do:

sudo su
echo brcmsmac >> /etc/modules
exit


Sorry, I underestimated the power of xkb, it can do much more than I thought. It is the most basic and overall keyboard manager of X-server. I have met my requirement using xkb. A very useful tutorial can be found at here on the Arch Linux Wiki, if you are also interested in how to do that. It is also welcomed to post on this topic.
Here are the details for my case (though I strongly recommend reading the linked page because it is very useful and not too long):
First, get your present keyboard layout:
xkbcomp $DISPLAY ~/.config.xkb

Then open the .config.xkb file with some editor, say vscode. You can see the file consists of 5 blocks(keycodes, types, compatibility, symbols, geometry):
xkb_keymap {
xkb_keycodes "..." {...};
xkb_types "..." {...};
xkb_compatibility "..." {...};
xkb_symbols "..." {...};
xkb_geometry "..." {...};
}

In the xkb_types block, add:
type "newType" {
    modifiers= Shift+Control;
    map[Shift]= Level2;
    map[Control]= Level3;
    map[Shift+Control]= Level3;
    level_name[Level1]= "Base";
    level_name[Level2]= "Shift";
    level_name[Level3]= "Control";
};

In the xkb_symbols block, find the following two sub-blocks:
key <AC06> {
    type= "ALPHABETIC",
    symbols[Group1]= [               h,               H ]
};
key <AC09> {
    type= "ALPHABETIC",
    symbols[Group1]= [               l,               L ]
};

And change these two sub-blocks to:
key <AC06> {
    type= "newType",
    symbols[Group1]= [               h,               H,            Left ],
    actions[Group1]= [      NoAction(),      NoAction(),   RedirectKey(keycode=<LEFT>) ]
};
key <AC09> {
    type= "newType",
    symbols[Group1]= [               l,               L,            Right ],
    actions[Group1]= [      NoAction(),      NoAction(),   RedirectKey(keycode=<RGHT>) ]
};

Finally, reset the keyboard layout to the modified one:
xkbcomp ~/.config.xkb $DISPLAY

Appendix
In case that one will want to know how to map to Left/Right instead of Control+Left/Right, I add the appendix.
The only change is to replace the sub-blocks in xkb_symbols block with
key <AC06> {
    type= "newType",
    symbols[Group1]= [               h,               H,            Left ],
    actions[Group1]= [      NoAction(),      NoAction(),   RedirectKey(keycode=<LEFT>, clearmods=Control) ]
}


Two monitors - can I power down the unused second screen?

If You power down a monitor the system doesn't understand Your action. All windows and cursor at the switched-off monitor stay invisible. You may

Before switching off start System settings -> Monitors (or Displays. I have Ukrainian interface). Select a monitor to switch off and press a switch near to it's name. It make a monitor blank and transfers all windows to another monitor
or
Unplug the monitor from PC (it is not recomended for D-Sub). Maybe a problem with different voltages at PC and Monitor. I use this method at Notebook and HDMI monitor.


Rather than using the external notify-send, I suggest you use the pynotify library, and then you can append to existing notifications and the bubble will grow.


How can I check if my video card is installed properly?

Type in:

lspci | grep VGA

and you should get output like:

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)

In your case it should be NVIDIA Proprietary Dtiver instead of Intel


Your error message is caused by sudo being owned by deployer, in addition, the rights are set incorrectly. To fix the permissions, try something like chmod 4755 /usr/bin/sudo, as you own sudo currently.

To fix the ownership, you need to run chown root:root /usr/bin/sudo ...but you might need to be root for that. Unless you have +s set on /bin/chown, and without root password or recovery console/alternative boot method, there is probably no way. So, you can try the above chown command with your normal user, but most likely you will have to re-install.

More similar questions:

Error after sudo-ing "sudo: must be setuid root"

sudo: must be setuid root


Note:

As of Ubuntu 12.10, Unity 2D is no longer developed and all systems use Unity 3D (with LLVMpipe for systems without hardware acceleration).

The easiest way I have found is to look at the launcher:

Subtlety in the design of the of the launcher popups - Unity 3D lives up to its name with a darker shadow "3D" effect whereas Unity 2D is lighter and has a "2D" flat effect.

Unity 3D
  Unity 2D

If you don't trust your eyes you can rely on the system to tell you, just look at the desktop session variable, open a terminal and type:

echo $DESKTOP_SESSION

If it echoes back ubuntu-2d that means you are using Unity 2D and ubuntu for Unity3D.

But if you want a bit more details (and that's a big if), here is an extended review:

Unity 3D

Unity 3D has several features that set it apart, that are the result of it's "3D" nature and the capabilities afforded to it that way:

The launcher items fold when there are too many windows open or excess items pinned to the launcher.
Also, the trash can icon in Unity 3D is based on your current icon theme, and thus looks transparent in the default setup (when empty).
The Panel and Dash change colour to match your wallpaper when the Dash is open, and the launcher is mildly translucent by default.
The Dash icon is black on white, with a transparent border, and rounded edges.
Unity 3D is a Compiz plugin and requires Compiz, which means your graphics card must have 3D support, and you cannot run it on another window manager; so if you are running anything but Compiz with Unity - you are definitely not running Unity 3D.
Unity 3D's icons have a nice gloss+glow to them, and transparent/translucent edges.
Unity 3D takes advantage of compositing fully even for quicklists and Launcher item tooltips.
Unity 3D's panel has a shadow.
Unity 3D has a fully 3D workspace switcher with smooth animations and an orange glow.

  PLEASE NOTE:
  These images present a slightly modified launcher, in that I have the Launcher set to "Edge Illumination Toggles" instead of the default "Backlight Always On".

Unity 3D's Launcher with folded icons.

Unity 3D's Trash Icon

Unity 2D:

There are several differences in Unity 2D from Unity 3D. One of them is that the launcher items do not ever fold.
Also note the following:

Notable differences in Unity 2D

The Dash button is not translucent.
Other buttons are flat icons, and not transparent/translucent with a glossy appearance as in Unity 2D.

Also of note:

The launcher and Dash are not transparent when not using a composting window manager such as Compiz  or Mutter  (for example). In the Default install, Metacity has compositing enabled.
Unity 2D can run in different Window Managers, unlike Unity 3D. If you run top or gnome-system-monitor, you will notice that Unity 2D also consists of separate processes for the Panel, Launcher, and Dash.
As noted by fossfreedom, Unity 2D does not currently take advantage of compositing for Launcher item tooltips and quicklists.
The Panel + Dash do not adapt to your wallpaper when the Dash is open.
The Panel has no shadow.
Unity 2D's workspace switcher has no glow, and has slow animations with no smoothness to them.
When there is an overflow of items on the Launcher, there is no folding. The launcher only scrolls.


Headsets mic not working on skype Ubuntu 19.10

First, turn off your headset. then turn it back on, let it pair, click on the bluetooth manager icon in the system tray, select Devices, see if you can see this device, if it is automatically paired, make sure it is connected as an "Audio Sink". If not, right click on the device, remove the current connection, and then right click again, and connect to "Audio sink".

then, play a youtube video or anything that has audio output, go to pulse audio control, see if you can select this device, and see if you can hear anything. if you have poor audio quality, maybe your headphone is defective. try to pair with your phone and see if it play audio properly.

I have been using two bluetooth headphones (1 earplug) with my Ubuntu 16.04 for skype/zoom calls with no issue. Occasionally it could not automatically pair or won't list it, but dock the headphone and undock it often make it visible to the system again.

if everything works fine, open your skype, goto Tools\Audio video settings and choose this device. basically the audio input/output list in skype will look the same as the pulse audio devices.


How to change persian keyboard layout on Ubuntu 18.04?

You can use this repo on github to change the keyboard layout to the windows default.


python permission denied writing output to file

The problem here sudo python myFile.py >> log.txt is that you run sudo python myFile.py as root, but your shell is still running as your regular user, which means >> redirection won't work if you don't have permission to write to the log.txt

As George properly noted, you should do sudo bash -c "python myFile.py >> log.txt". Alternatively, if your myFile.py doesn't require root privileges, you can do python myFile.py | sudo tee log.txt


How can I add an account to the sudo list?

You can edit the file /etc/sudoers using the visudo command which checks for syntax errors before saving the file (and so protects your system):

sudo visudo

Search for the line root ALL=(ALL) ALL and add a new line below: username ALL=(ALL) ALL.


Well the fish shell used interactively will remember entire commands used of which ip and url commands would be a subset. Fish shell will show you a previously run command in another color ahead of what you are typing in the terminal. to install run sudo apt-get install fish. by running the fish command you can start a fish shell and then autocomplete basically anything you want. running help will get you a lot more options.


You CANNOT uninstall an os, the only option you have is to format its partition and overwrite its bootloader with another one.

In your case it seems like that you have two ubuntu installations on different drives and a vista installation too? and you now want to remove one ubuntu installation.

IMO, you should start your computer in ubuntu you want to use, open 'gparted', delete the drive of ubuntu that you DO NOT want to use and format it to some  other usable partition. Then just run in a terminal,

first,

  sudo grub-install /dev/sda

and then,

  sudo update-grub

That will sort out grub entries for every os that you have in your system.


How to show size Ram and CPU ussage in Ubuntu?

You have two options or even more for doing so, the one delivered with ubuntu itself is the command top, and you can as well have it more comfortable with htop which you need to install through sudo apt-get install htop.


unzip unable to find file with spaces in file name

You should use \ for the escape character so that it knows there is a space where ever there is a space in the filename:

unzip IBM\ SPSS\ Statistics\ 24\ Linux.zip

Hope this helps!


Disable Ubuntu Gnome 13.04 sound amplicifation

There are a couple of things you can try to fix that issue. It really depends on a set of particularities of your sound card and Linux drivers. But you can try this:

Take a look at this question: Adjust PCM volume? The master and PCM volumes referred in that question are set with alsamixer.
Install pavucontrol and see if any options help: sudo apt-get install pavucontrol


Increase laptop screen resolution over 1024x768 on HP Compaq Presario v3000

ONLY If installing drivers for your GPU doesnt help. [Should be at Software & Updates >> additional drivers]
Try looking here : How to make my maximum screen resolution to be detected by Ubuntu? Look at the answer provided by Venki
I had the same problem and that helped me. But on the first command instead of :

cvt 2048 1536

I used:

gtf 1280 1024 60

gtf [horizontal res] [vertical res] [refresh rate]

If you get odd looking fonts after following the linked post, use :

sudo add-apt-repository ppa:no1wantdthisname/ppa
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install fontconfig-infinality

Not sure if that package above will help but it did help me.
If it doesnt you can uninstall it by:
sudo apt-get remove --purge fontconfig-infinality
sudo ppa-purge ppa:no1wantdthisname/ppa


Open your terminal and write:

cd /etc
sudo nano resolv.conf
#comment the line of nameserver 127.0.0.53 if it was found
#type:
nameserver 8.8.8.8
nameserver 8.8.4.4
#then click ctrl + x to save, press y, press Enter

finally, write inside the terminal the following command to restart the network service:

sudo service network-manager restart


There is a known bug in Linux 2.6.38 and newer kernels that cause bigger power consumption and more heat. Here is related Ubuntu bug:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/760131

Here is link to my article about a workaround that was discovered by fantastic people from Phoronix:

http://www.techytalk.info/linux-kernel-2-6-38-2-6-39-power-regression-workaround/

I would post link to original Phoronix article but I'm not allowed to post more than two links here and I think you'll benefit most from these two. Inside TechyTalk article you'll find link to Phoronix article with detailed explanation and two ways to apply workaround that works for most people but the safe bet would be to stay on 10.10 like most people until at least kernel 3.2 that could bring permanent fix.


Used a .desktop file to launch dolphin as root with gksu.

Content:

[Desktop Entry]
Name=TEST
Comment=Open TEST with root
Exec=gksu dolphin /media/TEST
Icon=file-manager
Terminal=false
Type=Application
Categories=Application;System;

If anyone finds a better way, feel free to answer and I will accept!

For example gksu requires the password every time, a way that doesn't need it would be appreciated.


Lubuntu / LXDE make the panel like in Ubuntu / MacOS

I'm not sure if I understand correctly what your system is but for a simple Lubuntu system (which comes with LXDE and other requisites), clicking anywhere in the blank area right at the top or the bottom of the screen should bring up this:

Then, in that window, clicking on "Panel Settings" should bring up this:

The options are self-explanatory here and the choices are quite a few.

As I said, this is with a proper Lubuntu installation.


In Linux a loopback adapter is valid only inside of its owner. You can't ping or communicate it from remote devices (You can remote access to loopback on Cisco devices)


What you have is pretty close to what I have in mind. Specifically, you can try something like this:

Host spinningatinfinity
  HostName something.compute.amazonaws.com
  User ubuntu
  IdentityFile ~/.ssh/id_rsa

Note that the default username for a Ubuntu image in a AWS EC2 instance is ubuntu, so you need to specify that as an argument for the User keyword to avoid typing it at the command line. In addition, if you use AWS to generate your SSH keys, the private key is actually a .pem file, so adjust IdentityFile accordingly if that is true for you. Now you can SSH just using:

ssh spinningatinfinity


Firefox doesn't display any website with AppArmor enabled

I had the same problem and fixed it with the apparmor profile I found on this page:

https://samiux.blogspot.it/2016/08/howto-hardening-and-tuning-ubuntu-1604.html

Hope it helps you as well.


On dconf-editor go:
com / canonical / indicator / date time then scroll down to "time format" and click on the words to open and change it to custom
(near the bottom, turn the use default value off, under custom value change the value to custom.


DejaDup - Clearing settings due to backup troubles

You can delete files from the Ubuntu One web interface, located at

https://one.ubuntu.com/files/

Click the "More" button on the far right

For details see Ubuntu One Tutorial


How do I fix black screen issue on my laptop?

This answer doesn't so much promise to solve the problem as much as to at least permit you to watch videos in the meantime while you are figuring it out.  You may even need to watch a video in order to solve your problem, so, anything that works, right?

If your computer has a working cd/dvd drive, please boot your computer to an ubuntu LIVE CD, such as 12 or 13, connect to the internet with it, and attempt to see if it will display videos.

I am betting it will, and I think you will agree that would be convenient.


take a look at this post. There's a SHELL script which lets you write/read to/from your Dropbox account, and also there's a headless Dropbox installation which lets you access your account via the command line. To install it, issue these commands:

32-bit:

cd ~ && wget -O - "https://www.dropbox.com/download?plat=lnx.x86" | tar xzf -

64-bit:

cd ~ && wget -O - "https://www.dropbox.com/download?plat=lnx.x86_64" | tar xzf -

Next, run the Dropbox daemon from the newly created .dropbox-dist folder.


Run

gksudo gedit /etc/apt/sources.list

In the resulting Gedit, change all the lines with https to http.

Ex: https://deb.nodesource.com/node/dists/qiana/main/source/Sources to http://deb.nodesource.com/node/dists/qiana/main/source/Sources

Then save and close the file

Then run an update.


Does the Kubuntu installer get less attention than the Ubuntu installer?

A Kubuntu developer has a blog explaining Kubuntu's relationship to Ubuntu. If you want help, check the Kubuntu wiki or Kubuntu help and support.


Upgrade aborts half-way through with the error message there is too little space in the /boot folder

Basically, each time you upgrade the kernel, it doesn't remove older versions.  This is a good idea since sometimes, you might want to go back to the older version.  However, it is unlikely you will want to go several versions back.  So, yes, those are safe to remove.

Alok's link is fine.  I personally use Ubuntu Tweak, which has an option to clean up old kernels.  Any of the options are fine, but you might feel "safer" with Ubuntu Tweak, even though it does the same thing as what Alok's link does but puts a fancy GUI up front.

PS:  apt-get clean is not broken.  It clears out the local repository of retrieved packages but not the /boot directory.  You need enough space in the boot directory for the new kernel in 14.04.  Actually, the problem you are experiencing isn't because of 14.04.  The next time you upgrade the kernel in 13.10, you would have the same problem.  It's just by coincidence that you're seeing /boot used up when upgrading to 14.04.


setting up networking without network-manager

You need to do 2 things:

Remove network manager:

sudo apt-get purge network-manager

Alternatively you can disable it without uninstalling:

sudo stop network-manager
echo "manual" | sudo tee /etc/init/network-manager.override

Configure your network interfaces with ifup:

sudo ifup eth0
sudo ifup eth3

The interfaces marked with auto in /etc/network/interfaces are brought up automatically at boot. So actually this step is only needed to bring them up manually.

To bring an interface down, use ifdown.

--

References:

https://help.ubuntu.com/community/NetworkManager
How can I completely remove NetworkManager?


There is no such device these days.  I believe what you want is:

arecord -f S16_LE | ./noise-filter > bits


Problem was solved by simply removing pulse folders from /home directory then running pavucontrol in terminal successfully launched pulseaudio server. As I asume the issue was in one of the pulseaudio configuration files in home folder.
If it failed to create sink input and if you do not have any output sound after your PC or laptop has been suspended (hibernated) or after poweroff, using a terminal execute this command:
rm -r ~/.pulse ~/.pulse-cookie ~/.config/pulse

After, if it prints that some of the folders cannot be deleted because there's no such folders just wait a couple of seconds the sound shoud be back on.
if not run:
sudo pulseaudio -k
pulseaudio --start


Ubunutu 18.04 LTS fresh install - Stuck at grub OS selection screen

I just enabled legacy boot from System Bios and the grub loader started working. Here is the link on how to do it.

https://support.hp.com/ie-en/document/c03653226


is part of ubuntu-drivers-common

If you search for this package you will find

http://packages.ubuntu.com/trusty/ubuntu-drivers-common

And on that page is information of filing bug reports and maintainers

Maintainer:

Ubuntu Core Developers (Mail Archive)
Please consider filing a bug or asking a question via Launchpad before contacting the maintainer directly.

Original Maintainer (usually from Debian):

Ubuntu Developers (Mail Archive)
It should generally not be necessary for users to contact the original maintainer.

email ubuntu-devel-discuss@lists.ubuntu.com

See also How do I report a bug?


Sluggish desktop/Unity performance on ThinkPad Edge

Well, you could try the latest intel drivers from here: https://launchpad.net/~xorg-edgers/+archive/ppa but this might as well make things even worse.


Resolved,
All proxies were set, with "appropriate" scheme" in front

http_proxy=http://135.245.48.34:8000/
https_proxy=https://135.245.48.34:8000/

What "works" (at least with this proxy) is having "http" scheme for all

http_proxy=http://135.245.48.34:8000/
https_proxy=http://135.245.48.34:8000/


you can try to start your system with a live CD or USB drive, then try to find your backup file and restore it. If you have your data in a separate /home partition then you can try to reinstall your system again.

hope that helps


Install Compiz Config Setting Manager (ccsm):

sudo apt-get install compizconfig-settings-manager

Open it, in Desktop select Expo
On first tab pass by clicks on reset buttons on right edge. Do same thing on remaining tabs.


130.4 is very slow and killing my internet connection

It's hard to tell, but it seems that your experiencing two different problems.

For the network, you need to isolate the machines from the problem.

Turn on both machines
Make sure there idle
Turn of networking from the network manager indicator
Test your network "speed" again. (from some other internet connected device)

If it's better then turn networking on on one machine and test again from the same third device. If it stayed basically the same turn on networking on the second machine. Once you find the problem machine then you can start trying to narrow down that machine. Look for programs or processes downloading data. Apt get may be downloading updates, or dropbox may be syncing.

Finally if you can, on your router, find out how many connections each machine has open. It could be flooding your router with many small connections.

For general responsiveness, check the usual. Make sure you have enough free memory using free -m make sure the top is reasonable.

I had one old laptop, that a PCMCIA card would totally destroy any RF signal in 500m when I had it plugged in due to a driver bug.


Newly installed 12.04 on Radeon or NVIDIA type of gfx card?

Personally Nvidia , but the state of both ATI and NVidia drivers with compatibility it comes down to personal preference especially under unity , im not sure if that would change for gnome-shell


I see these questions all the time.  Installing Ubuntu alongside Windows, while supported, is not as easy as the other two options:

wipe windows and install Ubuntu
keep windows and run Ubuntu in a Virtual machine.

If you're an Ubuntu first timer.  Download VirtualBox and install Ubuntu as a virutal machine.  Play with it, get used to it.  You may come to find out that you like it better than windows.

When you're ready to go "full Ubuntu", back up your data (music, pix, docs) from windows and then do a fresh clean install of Ubuntu.

Note: While my answer won't help install Ubuntu alongside windows (which is very well documented), it does show two other options. I fully expect your down votes.


Sounds like a hardware problem from here - you very likely have an intermittent short or a mechanical issue in the button on the front of the drive.  Replace the drive.


How do I find the kernel version, Ubuntu release and disk partition information from the terminal?

uname -a for all information regarding the kernel version,
uname -r for the exact kernel version

lsb_release -afor all information related to the Ubuntu version,
lsb_release -r for the exact version

sudo fdisk -l for partition information with all details.
For more understandable information regarding paritions, please use commands given in other answers.


Which package will provide pygtk, gtk, pyserial and libsvg2-common for Inkscape extension

I have found the answer. I needed to install libgtk2.0 or libgtk3.0.


Webcam not working on Ubuntu 16.04 with vmware

Change USB Compatibility to 1.1 in Virtual Machine Settings.


What program to use when you want to create a persistent storage live usb IN Ubuntu?

NOTE: With the release of Ubuntu 20.04 Python 2 has been deprecated and Live USB will not work with 20.04 due to missing dependencies.  It will still work with 18.04 LTS.

The Startup Disk Creator which is also known as usb-creator-gtk has had the ability of persistent and erase removed from the application, thus in my opinion making it worse then it ever has been.  I wrote an answer earlier about it here.   Also, just using the usb-creator-gtk with Ubuntu 16.04 as well as dd cause the USB drive to be formatted with a 512byte instead of 2048 as it is listed causing issues with GParted and other applications from seeing the drive properly.  Unetbootin in my recent tests would not make the 16.04 USB bootable, especially if the drive was formatted as ext4.
I have found Live-USB-Install works very well and seems really stable.  We will create an Ubuntu 16.04.1 LiveUSB with persistence.

Download Live-USB-Install from here:
http://live.learnfree.eu/en/download/

Install Live-USB-install (requires unrar):
 sudo apt install unrar
 sudo dpkg -i /path/to/download/live-usb-install-2.5.11-all.deb

If it gives you any dependency problems, just run the following:
 sudo apt -f install

From the command line, now run Live-USB-Install (have your USB drive inserted that you're going to use.  We will format the USB drive):
 sudo live-usb-install

After the program launches, select the ISO you are going to use:

Click Open to Select ISO file

Select the proper USB drive and the Format button to format your USB to FAT32 (syslinux won't install in anything other than NTFS or FAT32):

After formatting, remove and reinsert the USB drive.

Select Refresh so it sees your drive again.

Select Distribution, Version, Persistent and Size you want for storage (for now 4095 or 4GB is the maximum due to size limitation of FAT32):

Click OK and be patient, this will take a while to create.

Boot to USB and select the persistent option.

You should now be able to install applications into the LiveUSB and still be there on a reboot.  Enjoy!

NOTE: I tried booting to a Mac (which uses EFI), and it didn't load the menu so it didn't load the persistent.  On the USB in the /boot/grub/grub.conf file I did this change adding the word persistent to the linux line:
menuentry "Try Ubuntu without installing" {
    set gfxpayload=keep
    linux   /casper/vmlinuz.efi  file=/cdrom/preseed/ubuntu.seed persistent boot=casper quiet splash ---
    initrd  /casper/initrd.lz
}

Then it seemed to load the persistent OK.  I didn't get the full chance to test it out though.

Hope this helps!


Looks like we can't until Linux catches up with Intel RST.
Switch Raid from RST to AHCI in BIOS and Windows stops booting, but the Linux install can see the drives.
No way around it beyond formatting and installing Windows on an AHCI RAID.


Ubuntu 13.04 does not show any icons when i login to ubuntu

Your graphics driver is probably not compatible with your graphics card, this happend to me when I installed a wrong driver for my nVidia, so first know your graphics card :
you can log on to the tty session to use the terminal by using
Ctrl + ALT + F1
then :

lspci | grep VGA

then download the necessary drivers

after installing restart by

sudo shutdown -r now


Unable to install VBoxGuestAdditions 5.1.0 on Ubuntu 14.04

it seems that there were some prerequisites you did not fulfill
something like:
apt-get install build-essential module-assistant linux-headers-$(uname -r)

it worked for me.


How to increase size of primary partition?

Download this file Now from your terminal do following. For example we want to make it 20 GB then:

cd ~/Downloads/wubi-resize-1.6
sudo bash wubi-resize.sh 20

Reference:

https://help.ubuntu.com/community/ResizeandDuplicateWubiDisk


How to find a keyboard shortcut, globally: ctrl-shift-P

It seems to me you don't have to uninstall everything, just do not launch anything.

Just restart and close all the applications that started up with the system. Application global shortcuts won't work if the application is not running.
Hit Shift+Ctrl+p to be sure this is an application global shortcut and not a system shortcut
Then, launch one by one and check if the global shortcut occurs (by pressing the keys while not focusing the launched application in order to be sure the shortcut is global).


Cannot install Fragment Image Viewer on Ubuntu 14.04

Try it again i tried installing, it worked fine and installed

They might have updated their ppa for Trusty, i did not get any error with "sudo apt-get update"


Allow DISPLAY access for a user not logged on GUI

You can allow all local (ie logged in) users to use the display by giving the command in a terminal on the graphics screen:

xhost +local:

Depending how you start your server you can put this command in a startup file, or even configure the server with the option.


Accidentally deleted /boot/efi / can't boot back into machine at all

No guarantees, but you ought to be able to boot a live CD / live USB linux, mount partitions and sxport your data from there.


wierd poblem with shaders on minecraft without report

The shaders are likely utilising OpenGL/GLSL features that your graphics card and its driver have not yet implemented. Even if hardware can do something, it needs the software there to interpret it and these drivers sometimes lag behind their Windows counterparts.

This is most true on the Intel and other open source graphics drivers. They are currently hovering around OpenGL 3.1 while the current proprietary Nvidia and AMD drivers will give you 4.4.

So if...

You're on the open source Nvidia driver, upgrade to their proprietary driver.
You're on open-source AMD, consider installing their proprietary driver (some people seem to struggle with it though so be cautious).
You're on Intel, you have little choice. Hardware upgrade or wait it out.


Yes, snap package can use the GPU.
To check whether a snap package has access to GPU acceleration, run the following command. Assuming you want to check for chromium, you can see that the snap package has been configured to use GPU acceleration.
$ snap connections chromium
...
opengl                    chromium:opengl                    :opengl                         -
...
$

For the case of chromium, you can test with WebGL demo pages.


How to Measure the Bandwidth Utilization of a Link

Several methods are possible, but here is one: run tcpdump on either of the servers and have it measure traffic to and from the port on the local host. Write this to a large dump file and use something like tcpstat to extract the total length. Another one: have your socket program itself calculate the amount of data sent and received at the socket level, and work out the IP and ethernet or other link layer overhead to get the amount of data on the line. Divide by time to get bandwidth utilization.


I need the default set of software sources to recover my installation

here is a copy of mine

# deb cdrom:[Ubuntu 11.04 _Natty Narwhal_ - Release i386 (20110423)]/ natty main restricted

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

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

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

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

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

deb http://security.ubuntu.com/ubuntu natty-security main restricted
deb-src http://security.ubuntu.com/ubuntu natty-security main restricted
deb http://security.ubuntu.com/ubuntu natty-security universe
deb-src http://security.ubuntu.com/ubuntu natty-security universe
deb http://security.ubuntu.com/ubuntu natty-security multiverse
deb-src http://security.ubuntu.com/ubuntu natty-security multiverse

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

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


How do I install Filmora video editing software on Ubuntu?

As far as I know it doesn't support GNU/Linux. You may try using Wine to install the Windows version, but I'm not really hopeful that it would work properly under Ubuntu.

You may look into some alternatives to work with Ubuntu:

OpenShot
Pitivi
Shortcut
kdenlive
Avidemux

etc.


What is TeXdoctk? Is it safe to Remove? How do I remove it?

So what exactly is it?

TeXdoctk is a TeX documentation browser
TeX is a system for typesetting.  For example it's used for some of the Debian manuals.

TeXdoctk is clearly old and klunky, but so far I haven't found anything better for TeX.
This description below could I think be said more simply as "Use a menu to display TeX help".

Also, seems some of the stuff in them menu is not loaded, in other words the menu is created NOT from your system, but globally somewhere, and your system may, or may not, have that documentation loaded.


You can use lsof it self for same activity. Execute below command in your terminal

lsof | grep 15287


The problem is, the normal way doesn't work in your control file for Build-Depends.

Build-Depends: g++ (>= 5.1.0)

But you could use g++-5.1

Build-Depends: g++-5.1

But this more like a cheat and will fail on all systems with g++ newer than 5.1.


Prevent that browser loads a site from cache which is protected by basic authentication

Try ctlr+F5 to reload page , Apache will send all of contents.
And also apache has a bit cache on memory . You can try echo 3 /proc/sys/vm/drop_caches


Decrypt $HOME from Separate Partition after re-install

Lucky you! I just had the same problem and wrote a script that will facilitate mounting ecryptfs Folders with FNEK.

sudo su -

Then open nano/vim/your editor of choice and create a file ecryptfs-fnek-helper.sh with the following contents:

#!/bin/bash

# Thanks to https://bugs.launchpad.net/ubuntu/+source/ecryptfs-utils/+bug/455709
#

echo "Where is the /home with the .ecryptfs mounted? (default=/mnt/home)"
read home_ecryptfs
if [ -z "$home_ecryptfs" ]; then
    home_ecryptfs=/mnt/home
fi
home_ecryptfs=$home_ecryptfs/.ecryptfs

echo "Whose encrypted home would you like to mount?"
read user
if [ -z "$user" ]; then
    echo "You have to enter a user!"
    exit;
fi

echo "What is the user's password?"
read -s password
if [ -z "$password" ]; then
    echo "You have to enter a password!"
    exit;
fi

echo "Where would you like to mount it? (Default: /mnt/[username])"
read target
if [ -z "$target" ]; then
    target=/mnt/$user
fi
target=$target/
mkdir -p $target

wrapped=$home_ecryptfs/$user/.ecryptfs/wrapped-passphrase
sig=$home_ecryptfs/$user/.ecryptfs/Private.sig
private=$home_ecryptfs/$user/.Private/

echo I will be mounting $private into $target.

echo "Clearing the keyring."
keyctl clear @u
keyctl list @u

echo "Unwrapping passphrase and inserting it into key:"
printf "%s" $password | ecryptfs-insert-wrapped-passphrase-into-keyring $wrapped -

keyctl list @u

echo -e "\e[0;92mPassphrase:"
echo -e '\e[1;92m'`printf "%s" $password | ecryptfs-unwrap-passphrase $wrapped - `'\e[0m'
echo -e "\e[0;96mFilename Encryption Key (FNEK) Signature:"
echo -e '\e[1;96m'`tail -n1 $sig`'\e[0m'
echo -e "Mounting now! Be sure to enable FNEK!"
mount.ecryptfs $private $target -o ecryptfs_cipher=aes,ecryptfs_key_bytes=16,key=passphrase

This will unwrap your passphrase and add it to the keyring. It will also display the passhprase and the correct FNEK signature, so you can copy/paste them when prompted by mount.ecryptfs.

Make the file executable and run it while still in su:

chmod +x ecryptfs-fnek-helper.sh
./ecryptfs-fnek-helper.sh


There is no database entry for Magix in the appdb, so we can assume that nobody else tried.

Launching the program from the terminal and pasting its output would be helpful for analysis. You should report a bug to the Wine developers using the latest version.

I understand that this program has a workflow which is nice and easy for you, but if you browse around some sites on the web focused on web design you will realize that designers mostly work with text editors, web browser developer tools and documentation (HTML, DOM, CSS, JS, etc). Here is an example of such a site.


Ubuntu 16.04 erases /etc/resolv.conf after restart

Hello Saturne64 and welcome to Askubuntu! The contents of /etc/resolv.conf are ultimately overwritten, but we can still set your DNS server of choice for your computer through the Network Manager. Please follow these steps:

Click the wifi icon at the top-right of your screen and choose "Network Connections"
Click "Edit"
Click the "IPV4 Settings" tab
Next to "Method: ", click "Automatic (DHCP)" and choose "Automatic (DHCP) addresses only"
In the text box adjacent to "DNS Servers: ", type the address of your preferred DNS server.
Click "Save" and in a terminal, run sudo systemctl restart network-manager.service.

Let me know if you need further assistance :)


Files take up more space on new RAID array

6*2TB RAID5 will give you between 8TB data and 4 TB parity and 10GB data and 2GB parity

The former gives you dual disk failure protection whereas the latter is discouraged as it gives you single disk failure protection without any further redundancy.  Also, depending on the UI, you will see the real usage (including parity) or the fake usage (excluding parity), so what you're seeing doesn't look abnormal to me.

The ideal RAID5 set-up is 5 disks+1 hot-spare.  The logic behind this being that you're buying all of the disks at the same time, so they will (probably) fail around the same time and if one of the disks fails, the hot spare takes over (that's why it's called "hot": it is powered on, but does nothing until one of the other disks fails) giving you time to order a new disk and continuing normal operations instead of "degraded mode" operations...

Now you can use the 6th disk not as a hot spare but as a hot drive giving you more parity, but you can also use it to increase storage and that one means sacrificing dual hard disk failure protection. and that is why it's discouraged...  ;-)

Have a look at this RAID calculator here and play with the numbers for more information.

For more information: Wikipedia RAID explained (read it all, including the history) and a specific article on RAID5


multilingual dictionary for ubuntu with IPA

You can install GoldenDict and download the relevant Babylon dictionaries from their web site. You will have to download the .exe file of and use 7Zip to extract the .bgl (dictionary) file from it.
The dictionaries also include the IPA.


Why does my computer only boot into Windows XP?

As soon as you see the BIOS screen hold Shift. This will take you to the GRUB screen.
From there you can select which operating system you want to boot to.

If this doesn't work then you might have to repair GRUB by booting into a live CD.

Then open a terminal and type:

//To find out in which partition Ubuntu is installed
sudo fdisk -l

Mount the partition:

sudo mount /dev/sda1 /mnt

Now install GRUB in that partition:

sudo grub-install --root-directory=/mnt/ /dev/sda


How to automatically switch default printers based on your location

This answer does not need sudo privileges
I assume you have two places with WiFi connections and two different Network Printers. Your laptop is setup to connect to these two WiFi connections. You have also setup your laptop's printer setup to the two printers and you can print to these two printers when connected to the respective WiFi networks.
For simplicity I will call the:

First WiFi network the "HomeWiFi" and the associated printer the
"HomePrinter".
Second WiFi network the "OfficeWiFi" and the associated printer the
"OfficePrinter".

I have written a bash script I call changedefaultprinter.sh you can name the file what you want and edit it as you wish. You will need to names of the WiFi and printers in the script to make it work.
The Script
#!/bin/bash
# File name: changedefaultprinter.sh
# Purpose: Change the default printer to home or office based on WiFi

############################
# User modification section
# Add WiFi and Printer pairs below:
WIFI1="HomeWiFi"
PRINTER1="HomePrinter"

WIFI2="OfficeWiFi"
PRINTER2="OfficePrinter"

# End of user modification section
############################

CURRENTWIFI=$(iwgetid -r)             # Get the name of the current WiFi

if   [[ ! $CURRENTWIFI ]]; then         # Not on WiFi
    echo "Could not find any WiFi, exiting..."
    exit 0
elif [[ $CURRENTWIFI == $WIFI1 ]]; then
    echo "Found $WIFI1, Setting $PRINTER1 as the default..."
    lpoptions -d $PRINTER1
elif [[ $CURRENTWIFI == $WIFI2 ]]; then
    echo "Found $WIFI2, Setting $PRINTER2 as the default..."
    lpoptions -d $PRINTER2
else
    echo "On unknown WiFi, exiting..."
    exit 0
fi

How to use:

Copy the script into a file changedefaultprinter.sh and save it in the location /home/$USER/bin. If you don't have the folder bin create it first. Make the file "executable". See How to make a file executable?

Find out the names of your WiFi and the default printers you have already setup. You can do this in many ways. I use the terminal and the commands below:

Make sure you are connected to your Home WiFi and and the home printer is set as the default. Open a terminal by pressing Ctrl+Alt+T and enter the command:
iwgetid -r

This should show you the name of your WiFi. Copy this name from the terminal and paste it into the file above where it says HomeWiFi.
Now to copy the name of the home printer use the command:
lpstat -t

You will see something like:
scheduler is running
system default destination: HomePrinter

Copy the name of the printer from the terminal and paste it into the file above where it says HomePrinter.

Now take the laptop to the office and repeat the same process to get the names of your office WiFi and Office default printer into the script. Replace the OfficeWiFi and OfficePrinter in the script.

Try it out:
In the terminal enter the command while connected to the home WiFi:
changedefaultprinter.sh

If all goes well you will see some text telling you your default printer is now set to your home printer. Do the same thing in the office to make sure it works there as well.
Make the script run when you login to the laptop
Open the application "Startup Application Preferences" and click on the button Add

Add a sensible name of the script so that you know what it does, and the location of the script as:
/home/$USER/bin/changedefaultprinter.sh
Where $USER is your username.
Click the Add to save the changes and close the "Startup Application Preferences" window. From now on every time you login to your laptop this script will run. It will determine which WiFi you are on and change the default printer.


How can I make a keyboard shortcut key to show the launcher when hidden?

There already exist many shortcuts for similar actions.

To show Launcher, hold the Super (aka "Windows") button for a short time.
To show Dash, click the Super button.
To see most useful Unity shortcuts, hold the Super button for a bit to see the shortcut window - there are many shortcut concerning working with windows, dash, HUD and other things.
To see what shortcuts are easily available to set in Ubuntu, run your Keyboard settings application.


How to start Unity desktop on a headless machine?

Unfortunately Unity will not load when running a VNC Virtual Mode session due to the requirement of 3D Graphics, you can run an alternative desktop window manager to get a graphical session however.

To do this you will need to change the ~/.vnc/xstartup file  (or /etc/vnc/xstartup if you do not have one)

There are instructions on the RealVNC website for this.


Problems installing Ubuntu Studio 17.10 in VirtualBox

A few days after I posted this question I tried downloading a fresh ISO for Ubuntu Studio 17.10 and it installed. This doesn't quite answer why the update from 17.04 wasn't working however.

I assume it was just a corrupt ISO. Hope this helps someone.


UFW BLOCK syslog - tcp/ip is blocked and this is allowed in UFW - GPS TRACKING/TCP/UDP report server

Looking at your rules and comparing them to your log brings up a few questions. It looks like you are trying to control all traffic to and from your interface. The problem here is that if you compare the blocked packet to your firewall list you have to find the rule that the packet matches. All of you blocked packets have destination ports that are on your list but source ports that are not. If my computer initiates communication with a standard http web server on your computer then my destination is port 80 and my source is some random number probably in the 50,000+ range. Let's just say mine is 62545. When your web server tries to reply to me it needs to be allowed to go out of you interface on port 80 destined for my 62545. Where on your allow out list is it permitted to have a packet to 62545? If there's no match then the packet will be blocked. If you look at the 2nd to last log entry displayed that is exactly the scenario I just explained. Nowhere on you list does it allow for a packet to go to 62545.

This leaves two things to consider. One, the firewall is stateful meaning if you initiate communication from your interface out to a destination port, say 80, the return packet will be allowed. The same packet could not enter your interface from the outside if not first initiated from the inside. I think you may be trying to control too much of your outbound traffic. That is unless, the second thing, you are controlling routing between interfaces. If that is the case the then the rule setup requires more information in your syntax (type: 'man ufw' from the command line for details). I typically enter detailed rules as I showed previously but only on the incoming side because I am not routing between interfaces. The detailed rule makes it easier to re-evalute the rules later if questions arise regarding the UFW configuration.Try dropping you allow out rules if you are not routing and see if the problem is resolved. I could be wrong but that is the way I interpret the UFW and the way I use it successfully. Good luck. hope this helps.


Per your updates moving the entire RAM contents to swap (which is required because you need to save/restore the RAM state) would take 3*1024/31 = 99 seconds. That is probably the main time consuming operation.


Just updated Ubuntu to 11.04 and my wired internet is down! Help?

Problem solved.  I edited /etc/network/interfaces which looked like this:

auto lo
iface lo inet loopback

 auto eth0
 iface eth0 inet dhcp

to look like this:

auto lo
iface lo inet loopback

 auto eth0
 iface eth0 inet static
     address 192.168.1.115
     network 192.168.1.2
     netmask 255.255.255.0

I'm not sure how it should have been correctly setup for dhcp, but what I have now seems to work fine, so I'll stick w/ that.


Problem with Bash script: 'declare: not found'

Are you using sh instead of bash? sh (linked to dash) does not support declare keyword, nor the syntax

VAR=(list)

for initializing arrays.


What are the limitations of the Windows Subsystem for Linux?

From the WSL FAQ:

  Can I run ALL Linux apps in WSL?

  No! WSL is a tool aimed at enabling users who need them to run Bash
  and core Linux command-line tools on Windows.

  WSL does not aim to support GUI desktops or applications (e.g. Gnome,
  KDE, etc.)

  Also, even though you will be able to run many popular server
  applications (e.g. Redis), we do not recommend WSL for server
  scenarios – Microsoft offers a variety of solutions for running
  production Ubuntu workloads in Azure, Hyper-V, and Docker.

There is also the official test for the Linux Test Program that provides some insight on pieces of software and if they work or come close to working.

The 2 links above are the official stance. One of the things Microsoft notes is that WSL does not aim to support a graphical interface. Users though have been able to run xfce and unity.

When someone can get unity to work on WSL I doubt there are any limitations. Lots of WSL is unproven ground so to get something to work might be up to the user (ie. in this case you ;) ).


If you use testdisk and photorec, it is capable of recovering the file you are able to store on that file system, as long as it doesn't exceed the file system limitation, for ext4, max file size will be 16TiB (for 4KB block file system).


If this is still an issue, I came across this today and figured out how to solve it. Apparently there's an issue with changing from a gpt to a msdos partition table. If you zero out the beginning of the drive, where sdb identifies your drive in /dev

sudo dd if=/dev/zero of=/dev/sdb bs=1M count=100

And then start from the beginning of the tutorial you mentioned.


lock some version so that it is not updated again

Open a terminal (Ctrl+Alt+T) and enter this command:

echo "firefox hold" | sudo dpkg --set-selections

This command locks your package and prevents it to be updated.

Undo

If for any reason you change your mind and want to update it, simply replace hold with install:

echo "firefox install" | sudo dpkg --set-selections

Check status

To check the status of a package if it will be updated, enter:

dpkg --get-selections | grep firefox

Note it’s better to lock other packages related to firefox as well, such as firefox-globalmenu, firefox-gnome-support. You can see all of them by checking the status, then enter the lock command for each separately:

echo "firefox-globalmenu hold" | sudo dpkg --set-selections

echo "firefox-gnome-support hold" | sudo dpkg --set-selections

echo "firefox-locale-en hold" | sudo dpkg --set-selections

– these are just examples, on your computer you may have different locale packages.


How to properly view a .sqlite file using sqlite?

Let's start with the more user-friendly way and use the GUI tool sqlitebrowser. It offers you to easily explore a database without having to know SQL commands.

You can install it with the command

sudo apt install sqlitebrowser

and run it from the launcher/dash/application menu or using the command

sqlitebrowser

In the main window you can click Open database to open your *.sqlite file. It will then display something like this (here displaying the database of a Firefox add-on for applying user styles):

I already switched to the Browse Data tab on the left panel, where you can view the database table contents now. You select which table to display in the "Table:" combobox.

Of course you can also do this from the command-line, using e.g. sqlite3. This method requires you to know at least a basic set of SQL commands and is better suited for advanced users or if you need to parse the output in a script.

You install sqlite3 using the command

sudo apt install sqlite3

and then run it with the following command (-column and -header option for better readability of the output, see man sqlite3 for more info):

sqlite3 -column -header

Then you get an interactive SQLite3 command prompt, like this:

$ sqlite3 -column -header
SQLite version 3.11.0 2016-02-15 17:29:24
Enter ".help" for usage hints.
sqlite>

The first thing you must do now is to open the database file. Therefore you can use the .open SQLite command. Enter this to the sqlite> prompt (again using the same Firefox add-on database as above, you will type a different path of course):

.open "/home/bytecommander/.mozilla/firefox/gtltfeay.default/stylish.sqlite"

Note that Tab completion works here and will help you to enter the path to your database file.

You can now see the list of loaded databases using the .databases command (file name is truncated because it's so long):

sqlite> .databases
seq  name             file
---  ---------------  ----------------------------------------------------------
0    main             /home/bytecommander/.mozilla/firefox/gtltfeay.default/styl

You see the database we just opened is now called main.

In the next step we list all tables of the main (default) database:

sqlite> .tables
style_meta  styles

We see the two tables style_meta and styles listed.

Let's display the style_meta table completely with all columns. Therefore we need the SQL command SELECT * FROM style_meta; (don't forget the semicolon!):

sqlite> SELECT * FROM style_meta;
id          style_id    name        value
----------  ----------  ----------  -----------
46          1           domain      lichess.org
47          1           type        site
48          3           domain      lichess.org
49          3           type        site
50          2           domain      lichess.org
51          2           type        site
53          4           type        global

To get help with commands specific to SQLite3's interactive shell (commands starting with a period), type .help at the sqlite> prompt or read its manpage man sqlite3. All other commands are common SQL, you should search for a basic SQL tutorial to learn them.

You can exit the interactive sqlite3 shell again using the .exit command or Ctrl+D.


Ubuntu 18.04 / Dell Precision 5520 - New install, no video over Thunderbolt 3

Figured it out. Turned out I had MST enabled on the Thunderbolt monitor... but there was not a monitor daisy chained. When I turned it off, everything worked as expected. Yay!


You could use this nice script:

http://ubuntuforums.org/showthread.php?p=6589810

It should upgrade your sound drivers to the latest version and uninstall the older ones first.


Install Windows 10 on existing Ubuntu 18.04.5 on 2GB USB

Installing Windows 10 without USB using Ubuntu GRUB

Backup the Target drive. This method might overwrite it. Normally Windows is installed before Ubuntu.

Download Windows ISO to your computer.

Create a 6GB NTFS partition on the hard drive and extract the Windows ISO to it.

Create a 20GB, or larger, NTFS partition on the hard drive for the Windows Installation.

Open Disks, (Gnome-Disks), and note Device, (/dev/sdx), and UUID of the Windows ISO extract partition.

For msdos partition table, copy the following menuentry to /etc/grub.d/40-custom/*:

menuentry 'Windows Recovery Environment (on /dev/sda4)' --class windows --class os $menuentry_id_option 'osprober-chain-592C85254E2CD0B7' {
    insmod part_msdos
    insmod ntfs
    set root='hd0,msdos4'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos4 --hint-efi=hd0,msdos4 --hint-baremetal=ahci0,msdos4  592C85254E2CD0B7
    else
      search --no-floppy --fs-uuid --set=root 592C85254E2CD0B7
    fi
    parttool ${root} hidden-
    drivemap -s (hd0) ${root}
    chainloader +1
    ntldr /bootmgr
}

Edit menuentry, changing sda4 to sdax, msdos4 to msdosx (4 places), and 592C85254E2CD0B7 to UUID, (3 places), to suit step 4 above.

Run sudo update grub confirm that ntldr /bootmgr appears in grub.cfg.

Boot the computer into the newly created Windows menuentry and install Windows into it's new partition.

Reinstall Ubuntu if desired, the GRUB bootloader will have been replaced with the Windows bootloader.

*For gpt partition table, copy the following menuentry to /etc/grub.d/40-custom/:
menuentry 'Windows Recovery Environment (on /dev/sda4)' --class windows --class os $menuentry_id_option 'osprober-chain-592C85254E2CD0B7' {
    insmod part_gpt
    insmod ntfs
    set root='hd0,gpt4'
    if [ x$feature_platform_search_hint = xy ]; then
      search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt4 --hint-efi=hd0,gpt4 --hint-baremetal=ahci0,gpt4  592C85254E2CD0B7
    else
      search --no-floppy --fs-uuid --set=root 592C85254E2CD0B7
    fi
    drivemap -s (hd0) ${root}
    chainloader +1
    ntldr /bootmgr
}

Boot selecting Windows from the GRUB menu and follow the instructions.
Limitations
Windows 10 has limitations with respect to partition tables and boot modes.
I was able to install Legacy mode Windows to a drive with a MSDOS partition table.
I was able to install UEFI mode Windows to a drive with a GPT partition table.
I was not able to install Legacy mode Windows to a drive with a GPT partition table.
I was not able to install UEFI mode Windows to a drive with a GPT partition table and Legacy mode Ubuntu.
There may be workarounds that are outside the scope of this answer.


Unable to access NFS share from Mac OS X

I ran into this same issue myself when trying to mount a git repo directory from Ubuntu to OSX 10.10.3.

There were several things I did to make this work:

I set up a new group in Ubuntu called shared, to which I added a new user with the same name as my OSX user.  I also changed the group ownership of my git repository to shared.  I used the uid and gid for these in the next step.
Like you, I set up the NFS export and verified it using showmount.  However, in addition to rw, I also included the following: (rw,sync,no_root_squash,no_subtree_check,insecure,anonuid=<<uid>>,anongid=<<gid>>). I read somewhere that insecure is especially important when dealing with macs (something about tcp port restrictions).  Without that option, you're likely to get "operation not permitted" when mounting.
Spelled the damn directory path correctly - this turned out to be the most obvious problem, but took me the longest to figure out.  It seems that if the source directory in the NFS request does not exist, you get a "permission denied" instead of the more intuitive "directory does not exist".


Notification on Unity after i3 desktop removal

Try removing the following packages:

sudo apt-get remove dunst i3 i3-wm i3lock i3status suckless-tools

Then try:

sudo apt-get autoremove && sudo apt-get update && sudo apt-get install --reinstall notify-osd

That will hopefully clear this up.


Instead of creating a user, I found I could just use "lxc shell" to access a container as root. From there, I could use "lxc shell" again to reach the nested container.


I just found a solution for evince.

Basically the problem was that I had xenial-proposed updates activated and there was some conflict.

I just followed the instructions of http://www.webupd8.org/2013/11/how-to-downgrade-proposed-repository.html to downgrade the -proposed updates and get back to the stable ones.

After that evince is working as before and I can type in the search field. After the downgrade I experienced some problems with the audio card, but after a couple of cold reboots it was ok.


version `GLIBCXX_3.4.26' not found even though libstdc++.so.6 recent enough

Install "libstdc++6" and "gcc-9" helped me. Hope it will help you too.
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update
sudo apt install gcc-9
sudo apt install libstdc++6


I can't compile source, make doesn't work

open your terminal and type as

sudo apt-get install build-essential

then try again.

I am sure that's going to help you.


Manual says nothing about EFI.  but has multiple refs to the bios setup screen.

I'm thinking classic bios on this one.


Is it usual Ubuntu 14.04.2 to take a long time at "random: nonblocking pool is initialized" step during boot process?

I believe this particular step does not actually take a long time. The message in the dmesg log is printed when the pool has been initialized, not when initialization is started.

What Linux is doing in those 11 seconds is probably probing, identifying and initializing hardware, which does not necessarily generate entries in the dmesg log.


How do I convert a sysv-init script to an Upstart job?

I have written one here: https://bitbucket.org/CameronNemo/upstart-jobs/src/b5a709465304bdf420ca2507ed14f6fe67272de8/slapd.conf?at=master

A few mistakes you made:

There should be no -- between slapd and its options.
The start on events need to have an and between them.
virtual-filesystems should change to filesystem, as Letizia said.


Google chrome not opening in Ubuntu 20.04 LTS

Run this in the terminal and you should get it working :
rm -rf ~/.config/google-chrome

Though let me tell you that this will reset all your bookmarks, history. This is kinda like reinstalling chrome. If you had backedup your history into your email id then you can back it up easily after doing this command.


External monitor is disabled after resume (only on 15.04)

I have the same configuration and problem. One workaround I found is to go to one virtual terminal (e.g. Ctrl+Alt+F1) and then go back to the desktop (Ctrl+Alt+F7).


Wifi not working on Lenovo z570 Ubuntu 12.04

the Wifi issue has been fixed, once I have updated my Ubuntu machine, and the Wifi/blue-tooth are detected, etc. Also, the Wifi hardware it's not anymore flagged as UNCLAIMED, it's recognized now using the (lshw -C Network).

Best,


Can kdeconnect work in two networks at the same time?

Seems like I managed to obtain the result I wanted!
I created another ethernet connection with my connection manager , which I use for my ethernet wi-fi device, and I called it "Ethernet-Local" : under IPv4 Settings I selected   "Routes" and put a tick to "Use this connection only for resources on its network".
When I want to use the other phone's usb-tethered connection, I switch on the "Ethernet-Local" connection, and the two seems to co-exist in harmony! When I'm using M as an hotspot I switch back to the normal connection, called "Ethernet-Web",
it's even easy to automate
we'll need a script that gets launched everytime something changes between connections, and it must be owned by root
sudo nano /etc/NetworkManager/dispatcher.d/90-kdecon

And here's what's inside the script
#!/bin/sh

ethweb=$(nmcli dev | grep "Ethernet-Web" | grep -w "connected")
usb=$(nmcli dev | grep "usb0" | grep -w "connected")
ethlocal=$(nmcli dev | grep "Ethernet-Local" | grep -w "connected")

if [ -n "$usb" ] && [ -n "$ethweb" ] ; then
nmcli c up Ethernet-Local
elif [ -z "$usb" ] && [ -n "$ethlocal" ] ; then
nmcli c up Ethernet-Web
fi

need to make it executable
sudo chmod +x /etc/NetworkManager/dispatcher.d/90-kdecon


Why are there two icons in the Unity launcher for Nautilus?

According to the bug, you just need to remove the following line from your custom Nautilus launcher (~/.local/share/applications/nautilus-home.desktop):

OnlyShowIn=GNOME;Unity;

I had this problem and removing that line and logging out and logging back in worked for me.


How to display characters in (virtualbox) TTY?

Here's a link How to make the VT display chinese characters?

Which might be useful to you. Check it out and tell me.


It seems that there is no PID for the window. How do you kill this PIDless window?

It works with wmctrl and the window id.

First, install wmctrl if you don't have it:

sudo apt-get install wmctrl

Second, find the window id with:

$ wmctrl -mlpx
...
0x046000a4  0 0      Ansyswbu.exe.MainWin    N/A    A : Fluid Flow (Fluent) - Meshing [ANSYS Academic Research]
...

Last, kill the beast with a null PID wmctrl:

wmctrl -ic 0x046000a4


You can install Ubuntu GNOME, which, like Kali, uses the GNOME3 desktop environment, or more simply install GNOME3 on your current system. Other than that, probably the best you can do is to remove the tile background from the launcher icons, using these directions.


Why has my keyboard change layout settings?

Set your updates back to servers in the UK. Hong Kong servers cannot download updates in the UK keyboard layout. Besides, Canonical HQ is in the UK, so it is likely the servers in the UK are best.


GRUB: terminal instead of Grub menu list

I had the same issue but i resolve it with this tutorial: https://jacci.net/linux/pop-os/how-to-install-grub-on-pop-os-20-04/


what to do with ExecutablePath/usr/lib/nux/unity_support_test?

I am getting this error too, everytime I start up Ubuntu 12.04
I also cannot install fglrx etc etc etc... like you tried.
I could not find an official solution.

Here is my solution:

Open a terminal, then type

sudo su (THEN PRESS THE ENTER KEY)
Password:  Now type in your password  (THEN PRESS THE ENTER KEY)

Now you are the user called root.

Type in:
cd /usr/lib/nux  (THEN PRESS THE ENTER KEY)

Type in:
mv unity_support_test  unity_support_test_hold  (THEN PRESS THE ENTER KEY)

Type in:
reboot (THEN PRESS THE ENTER KEY)

Your system will reboot and the error message won't appear anymore.
At least it's not appearing for me... all gone.

It's kind of a slimey solution, but it worked.

George


WiFi not discovering networks Ubuntu 18.04 Macbook pro mid 2010

After 10 days of trying different solutions, finally, it is working.
The post here by  KiLLeRfriend is what solved my problem:

https://ubuntuforums.org/showthread.php?t=1745437

I am copying here for future reference:

I fixed my problem with the Broadcom bcm4311 drivers on 11.04 (Natty Narwhal)

Steps I took for fixing this problem: (I stole this method from http://ubuntuforums.org/showthread.php?t=1700897[user:nm_geo; post #5])

-open the 'Synaptic Package Manager' and search for 'bcm'

-uninstall the 'bcm-kernel-source' package

-make sure that the 'firmware-b43-installer' and the 'b43-fwcutter' packages are installed

-type into terminal:

[cat /etc/modprobe.d/* | egrep '8180|acx|at76|ath|b43|bcm|CX|eth|ipw|irmware|isl| lbtf|orinoco|ndiswrapper|NPE|p54|prism|rtl|rt2|rt3 |rt6|rt7|witch|wl']

(you may want to copy this) and see if the term 'blacklist bcm43xx' is there

-if it is, [terminal]cd /etc/modprobe.d/ [and then]sudo gedit blacklist.conf

put a # in front of the line: blacklist bcm43xx

then save the file (I was getting error messages in the terminal about not being able to save, but it actually did save properly)

-reboot

-sudo iw reg set "REGION"

-reboot


Is there any way to extend root filesystem ext4 space using home ext4?

From the comments... here's an outline of one way to resize your root file system, by deleting your swap partition, resizing /, and using a /swapfile, instead of a swap partition...

temporarily disable swap

sudo swapoff -a

comment out the swap line in /etc/fstab

#UUID=xxxx-xxxx-xxxx-xxxx-xxxx none  swap       sw       0       0

boot to a Ubuntu Live DVD/USB

delete your excessive p6 swap partition using gparted

resize p3 using gparted

boot back into Ubuntu

create a 4G /swapfile

Note: Incorrect use of the dd command can cause data loss. Suggest copy/paste.
In the terminal...
sudo swapoff -a           # turn off swap
sudo rm -i /swapfile      # remove old /swapfile
sudo dd if=/dev/zero of=/swapfile bs=1M count=4096

sudo chmod 600 /swapfile  # set proper file protections
sudo mkswap /swapfile     # init /swapfile
sudo swapon /swapfile     # turn on swap
free -h                   # confirm xG RAM and 4G swap

Confirm this /swapfile line at the end of /etc/fstab... and confirm no other “swap” lines...
To edit, use sudo -H gedit /etc/fstab or sudo pico /etc/fstab
/swapfile  none  swap  sw  0  0

reboot                    # reboot and verify operation


Is it possible to find out what options packages were compiled with?

Grab the source package

apt-get source vim

That'll download the source for the package in your current dir. Look at debian/rules, which is a makefile used when creating all the different vim packages. It may be hard to read, but the information you seek should be in there somewhere.

You can also download the source package from http://packages.ubuntu.com/source/trusty/vim (scroll down) if you can't log into a debian/ubuntu box to run apt-get.


On the terminal type:

sudo service lightdm restart


Try this

sudo php5enmod mcrypt

sudo service apache2 restart


Load Ubuntu without GRUB, Is it possible?

You can use Wubi to install ubuntu on your system. Wubi is Ubuntu installer for Windows. By using Wubi you can install, uninstall, and manage Ubuntu from windows.

All instructions are here

Wubi.exe still exists in Ubuntu images.


Cannot change association for mp4 video files to custom .desktop

You probably need to change mimeapps.list:
http://tuxdiary.com/2012/04/25/create-default-file-associations-manually-in-ubuntu-precise/


Unable to delete folder located in "Trash" in Ubuntu 18.04.4 LTS

Try to do it with root permissions:

Open terminal window (ctrl + alt + t)
Type sudo rm -rf /.local/share/Trash/* fro remove all Trash content with root permissions


How to change the resolution of my desktop?

Your monitor might not be capable of going up to those resolutions with the current drivers.  Check your hardware drivers by looking for proprietary drivers.  Also, please edit your question to include what system you're running, such as 10.04 vs. 10.10, Desktop vs. Laptop, etc.


How do I detach a screen session from a terminal?

Ctrl+a followed by d. Note the lower case. The [screen manpage] has a long list of these shortcuts under "DEFAULT KEY BINDINGS".


problems reinstalling ubuntu-desktop and purging gnome completely

I was able to run sudo apt-get -f install after this:

    sudo apt-get update
    sudo apt-get remove gnome-backgrounds
    sudo apt-get remove --auto-remove gnome-backgrounds
    sudo apt-get remove gnome-session
    sudo apt-get autoremove
    sudo apt-get update
    sudo apt-get dist-upgrade


As of February 2017, Microsoft has made these available though a public repository which brings all the repository goodness.  Details here.

Here are the instructions to install the latest version of PowerShell on 16.04.

# Import the public repository GPG keys
curl https://packages.microsoft.com/keys/microsoft.asc | sudo apt-key add -

# Register the Microsoft Ubuntu repository
curl https://packages.microsoft.com/config/ubuntu/16.04/prod.list | sudo tee /etc/apt/sources.list.d/microsoft.list

# Update the list of products
sudo apt-get update

# Install PowerShell
sudo apt-get install -y powershell

# Start PowerShell (MS renamed main executable at launch to be more Linux-like)
pwsh


Graphics bug after system updates Ubuntu 16.04 LTS

The bug is also reported here:
https://devtalk.nvidia.com/default/topic/995750/linux/375-39-causes-corruption-of-window-decor-on-ubuntu-after-suspend-resume/

The next release should fix this problem.
The temporary fix described here works for me:

echo -e '#!/bin/bash'"\n## This file (or a link to it) must be in the folder /lib/systemd/system-sleep/\n## Purpose: Kill compiz after system wakes up from sleep.\n## This will fix bad window borders caused by Nvidia driver 375.39.\nkill \$(ps -C compiz -o pid=)" | sudo tee /lib/systemd/system-sleep/fixbadborders
sudo chmod +x /lib/systemd/system-sleep/fixbadborders

To remove this script:

sudo rm /lib/systemd/system-sleep/fixbadborders


How to restore ubuntu-desktop-ubuntu-ubuntu-make-bionic.list

On my Xenial systems I have the similar files named

/etc/apt/sources.list.d/ubuntu-desktop-ubuntu-ubuntu-make-xenial.list
/etc/apt/sources.list.d/ubuntu-desktop-ubuntu-ubuntu-make-xenial.list.save

They have only one uncommented line:

deb http://ppa.launchpad.net/ubuntu-desktop/ubuntu-make/ubuntu xenial main

Which represents the PPA with Ubuntu Make utility.

You have to re-add it with:

sudo add-apt-repository ppa:ubuntu-desktop/ubuntu-make

Note: without *.list file the system will change the package status to locally installed or obsolete, this is not recommended. In this particular case the PPA provides newer version, so you can't reinstall the ubuntu-make package without this PPA added to the system.


Server 20.04.1 LTS "0 updates can be installed immediately, 0 of these updates are security updates"

How to edit the existing systemd timer to run apt update at the time of your choosing:
Edit /lib/systemd/system/apt-daily.timer. Simply change these two lines:
[Timer]
OnCalendar=*-*-* 6,18:00  <---- Change this to the time(s) that you want
RandomizedDelaySec=12h    <---- Comment out this line
Persistent=true

After editing, reload the timer:
$ sudo systemctl daemon-reload
NOTE for future readers: Unless you really need apt to run at a specific time, best practice is to leave the randomization in place to avoid hammering the Ubuntu servers with load at common times (that's rude). Thoughtful community members can use the RandomizedDelaySec setting to configure a window to spread that load and avoid hammering.

How to disable Unattended Upgrades:
Edit /etc/apt/apt.conf.d/10periodic.
APT::Periodic::Update-Package-Lists "1";           <--- apt update. leave it "1"
APT::Periodic::Download-Upgradeable-Packages "1";  <--- apt upgrade. Change to "0"
APT::Periodic::AutocleanInterval "1";              <--- Unattended Upgrade feature. Change to "0"

NOTE for future readers: Disabling Unattended Upgrades is not recommended for most users. UU is how most users receive security patches. The Ubuntu developers expect users to run UU, do not test systems without UU, and are likely to reject bugs that cannot be duplicated with UU running. Disabling UU is hiking into the wilderness on your own. This case is presented specifically because the OP is willing to be responsible.

How to discern between security and non-security upgrades: For most users, this is an exercise in curiosity only. Most users should be getting daily security upgrades via Unattended Upgrades, and the number of upgrades is not particularly useful information. The OP asked specifically for this information.
The login message summarizing upgrades available generally cannot be trusted to be accurate -- that message is generated by pam_login, and is based upon the most recent  apt-update...which might have been days ago in this case. Always-on systems usually update apt twice daily, so their variance will usually be small.
Here's one fairly easy, method to list the -security packages available for upgrade. You can get other repos the same way, by editing the first command:
Reminder: Run a fresh apt update before this to ensure that you have an accurate list.
$ grep security /etc/apt/sources.list > /tmp/security.list
$ apt list --upgradeable -oDir::Etc::Sourcelist=/tmp/security.list


This is more of a troubleshooting tip than a solution, but one can try: make sure the (latest) bash-completion package is installed and sourced (however, some later, unrelated installed bash completion scripts might've broken the default behavior), e.g.,

$ sudo apt-get install bash-completion
$ . /usr/share/bash-completion/bash_completion

(Note: /etc/bash_completion may simply be a link to or source the above file, in which case that's fine, feel free to use that. The default path to bash_completion varies across systems.)

Then see if the same problem continues to exist or not. If this resolves the problem, add the second line to the end of your ~/.bashrc so that it's set all the time, and/or troubleshoot & remove anything that may be breaking the default behavior.


Can't install mysql-server/client on ubuntu 16

We execute the following commands to solve the above problem:

Get the list of MySQL packages installed on the system by executing the command sudo dpkg -l | grep mysql
Remove the the packages shown above by executing the command sudo apt-get --purge autoremove <packages from the step 1>
Delete /var/lib/mysql
Try to install mysql again. It should solve your problem.


What does the second column in the output of 'ls -n' mean?

The second column is the number of hard links to the file.   For a directory, the number of hard links is the number of immediate subdirectories it has plus its parent directory and itself.

$ ls -n
total 0
$ touch f1
$ touch f2
$ ln f1 hardlink
$ ln -s f2 softlink
$ mkdir d1
$ mkdir d2
$ mkdir d2/a d2/b d2/c
$ ls -n
total 8
drwxr-xr-x 2 1000 1000 4096 2010-12-31 00:07 d1
drwxr-xr-x 5 1000 1000 4096 2010-12-31 00:07 d2
-rw-r--r-- 2 1000 1000    0 2010-12-31 00:06 f1
-rw-r--r-- 1 1000 1000    0 2010-12-31 00:06 f2
-rw-r--r-- 2 1000 1000    0 2010-12-31 00:06 hardlink
lrwxrwxrwx 1 1000 1000    2 2010-12-31 00:07 softlink -> f2

Linux Gazette Issue 35

Linux Gazette Issue 93


You could update your kernel to v3.5.4 by installing a mainline kernel.

Do mainline kernel builds include Ubuntu specific drivers?
By definition the mainline kernel builds are made from virgin unaltered mainline kernel sources and therefore do not, and should not, include any Ubuntu patches or drivers. There are also no binary drivers for these kernels.

Open a terminal and do the following:
mkdir v3.5.4-quantal
cd v3.5.4-quantal
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5.4-quantal/linux-headers-3.5.4-030504_3.5.4-030504.201209142010_all.deb

Only for 32 bit systems:
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5.4-quantal/linux-headers-3.5.4-030504-generic_3.5.4-030504.201209142010_i386.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5.4-quantal/linux-image-3.5.4-030504-generic_3.5.4-030504.201209142010_i386.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5.4-quantal/linux-image-extra-3.5.4-030504-generic_3.5.4-030504.201209142010_i386.deb

Only for 64 bit systems:
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5.4-quantal/linux-headers-3.5.4-030504-generic_3.5.4-030504.201209142010_amd64.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5.4-quantal/linux-image-3.5.4-030504-generic_3.5.4-030504.201209142010_amd64.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.5.4-quantal/linux-image-extra-3.5.4-030504-generic_3.5.4-030504.201209142010_amd64.deb

Install the kernel.:
sudo dpkg -i *.deb


How to effectively test deployment script

I ended up going with a virtual machine and saving/restoring the state. It's works very well for my purposes at least. It's a bit slower when building a lot of stuff, but you can have multiple "startpoints" depending on what part of the script you're tweaking...


Does following `man sudo root` permenantly blocks your sudo?

Following the instructions in man sudo root on how to go back to a tradidional root account does not permanently block sudo.

The first point to note here is that going back to a traditional root account is not recommended. The root log-on is disabled by default for a number of very good reasons and its almost never necessary to enable the root log-on.

Some benefits of leaving Root logins disabled by default include the following:

The Ubuntu installer has fewer questions to ask.
Users don't have to remember an extra password (i.e. the root password), which they are likely to forget (or write down so anyone can crack into their account easily).
It avoids the "I can do anything" interactive login by default (e.g. the tendency by users to login as an "Administrator" user in Microsoft Windows systems), you will be prompted for a password before major changes can happen, which should make you think about the consequences of what you are doing.
sudo adds a log entry of the command(s) run (in /var/log/auth.log). If you mess up, you can always go back and see what commands were run. It is also nice for auditing.
Every cracker trying to brute-force their way into your box will know it has an account named Root and will try that first. What they don't know is what the usernames of your other users are. Since the Root account password is locked, this attack becomes essentially meaningless, since there is no password to crack or guess in the first place.
Allows easy transfer for admin rights, in a short term or long term period, by adding and removing users from groups, while not compromising the Root account.
sudo can be setup with a much more fine-grained security policy.
The Root account password does not need to be shared with everybody who needs to perform some type of administrative task(s) on the system (see the previous bullet).
The authentication automatically expires after a short time (which can be set to as little as desired or 0); so if you walk away from the terminal after running commands as Root using sudo, you will not be leaving a Root terminal open indefinitely.

That said lets look at what these commands actually do on a live system.  Because the name of the group for administrator users changed from admin to sudo with the release of precise I tested this on both 10.04 and 12.04.  Both tests were using Virtualbox as I have no intention of bricking a real system.

Starting with Ubuntu 10.04 I enabled the root accout with sudo passwd root then edited the sudoers file with sudo visudo and rebooted.  When I rebooted only my name was listed and when I logged in sudo did not work.  However I was able to become root by entering su in a terminal and the root password.  I was also able to log out and back in as root.   root was not listed as a user but I could type it in.

Next I tried Xubuntu 12.04 I enabled the root accout with sudo passwd root then edited the sudoers file with sudo visudo and rebooted.  When I rebooted only my name was listed and when I logged in sudo still worked.  I was able to become root by entering su in a terminal and the root password.  I was also able to log out and back in as root.   root was not listed as a user but I could type it in.


how do I play local swf files in firefox

A workaround for this is to edit /usr/share/mime/packages/freedesktop.org.xml

and change
<mime-type type="application/vnd.adobe.flash.movie">

to
<mime-type type="application/x-shockwave-flash">

Then run the command:

update-mime-database /usr/share/mime

This answer is quoted from answer in ubuntuforums


How can I install OpenCL in Ubuntu 12.10 with a Lenovo G570 laptop?

I think that you have to download OpenCL for Intel, but not for the HD Graphics, as (my guess), it is not a GPU.
So , if you want to use OpenCL, you really need to install OpenCl to use with the CPU , that is , Intel.
Take a look here
http://software.intel.com/en-us/vcsource/tools/opencl-sdk
http://software.intel.com/en-us/forums/intel-opencl-sdk

p.s  My Lenovo has NVidia, then, I had installed NVidia driver and it comes with OpenCL ..

I hope it helps you.


Is there a way to manage my Grub menu options from with the GUI/desktop?

Yes, remove the packages.

Load up synaptic and search for linux-image. Click the first column to sort by packages that are actually installed and then click the green boxes to alter the state.

You're looking for packages that look like: linux-image-2.6.31-ubuntu10. Don't remove linux-image as that will stop updates coming in.

Just mark the ones you don't want anymore and then click apply. I would suggest (if you're happy with it) removing all but the current kernel and the one before it (just in case).

When you're done, click apply and grub gets cleaned up.


GNU GRUB error in Windows and Ubuntu dual-boot

Recover your grub. Follow the link
for a step by step approach

https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows


ValueError: need more than 1 value to unpack

Literally speaking, what is happening here is the code expects two values out the back of line.strip().split(' ||| ',1) (so it can assign those to s and r) but it's only getting one. Thus it explodes.

That's happening because you're not using the script correctly. If you look at the --help (or further up the code, line ~90), you'll see that it expects a very specific format:

parser.add_argument('-d', '--devset', required=True,
                    help='dev set input file in parallel. '
                    'format: src ||| ref1 ||| ref2')

You aren't following that so it can't split and therefore explodes.


Wired LAN is being connected, but can't access internet

This shows that the hostel does not support DHCP, so you probably do not have a default route set up. Type:

 ip route

to see your routing. You should see something like:

$ ip route
default via 10.32.3.100 dev eth0  proto static
10.32.0.0/16 dev eth0  proto kernel  scope link  src 10.32.3.100  metric 1

If you do, then this answer is inapplicable, ignore it. If you do not have a "default via" entry, do

If they gave you a "router address" use it, otherwise do:

$ arp -an

to list the IP addresses and MAC addresses on your Ethernet segment, and pick one. Use either the "router address" or one picked from arp -an,

$ sudo ip route add default via <IP Address> dev eth0


generate 2 random files 500MB with some common lines

Here is my suggestion from the comment in form of a smaller example:

    # generate the 2 basic files of 30 lines each
cat /dev/urandom | tr -dc 'a-f0-9' | fold -w 32 | head -n 30 > random1.csv
cat /dev/urandom | tr -dc 'a-f0-9' | fold -w 32 | head -n 30 > random2.csv
    # generate 3 common lines
cat /dev/urandom | tr -dc 'a-f0-9' | fold -w 32 | head -n 3 > common.csv
    # mix the common lines into the 2 files
cat random1.csv common.csv | shuf > random11.csv
cat random2.csv common.csv | shuf > random22.csv

Verifying:

$ cat common.csv
8b1df61042e621bb3cd3ba43942b5ada
71b2368e90c6eb038e84ef29446c0dec
56697847ec43cc181a556625ec880d85
    # select one common line and look for it in the 2 files
$ grep -n 71b2368e90c6eb038e84ef29446c0dec random11.csv random22.csv
random11.csv:13:71b2368e90c6eb038e84ef29446c0dec
random22.csv:9:71b2368e90c6eb038e84ef29446c0dec

So one of the common lines is line #13 in the first file and line #9 in the second file.

But beware of the needed resources if you take 30M lines instead of 30!


Can I have a textual Alt-Tab functionality?

I'm not sure it's advisable to attempt to change the window manager in Ubuntu 18.04. The window manager is integrated into GNOME Shell.

You may find Rofi suitable for the purpose you describe while leaving the system's default intact.

Rofi is available in the universe section.
It has an installed size of 524 kB and and very few dependencies which you can see by running apt show rofi or by simulating its install using apt install -s rofi.
Rofi has several functions but the one of interest here is the window switcher.

Once Rofi is installed:

Run rofi -dump-config > ~/.config/rofi/config.rasi to generate a local config file which you can modify to suit your needs.
Preview the theme you'd like to use by running rofi-theme-selector. If you want to tweak the theme further, you could copy the theme over from /usr/share/rofi/themes to ~/.local/share/rofi/themes and give it a new name to avoid confusion. I like Pop-Dark and named the local version myPop-Dark. In the images posted in this answer, I've used myPop-Dark.

Usage

To demonstrate Rofi's use as an alternative to the system's Alt+Tab:

I opened several windows including five xterm windows.
I assigned Ctrl+Win+R as a shortcut keyboard combination to run rofi -show window -theme myPop-Dark

In the image posted above, there are three columns. If you always want only the name of the application and the title of the window, edit ~/.config/rofi/config.rasi to change the commented out window-format line to

window-format: "{n}    {t}";

You can also modify the width, the height, and the location of the rofi window.

To bring the window you want into focus, use the arrow keys or your mouse pointer to highlight the entry and then press Enter.

If you have a really long list of windows, press a key that's unique to the window you want to filter out all other windows. If that's not possible, filter the entries by typing, as in the animation below, f, followed by o to limit the list to windows containing the string "foo".

The animation below illustrates that.

To close a highlighted window, press Shift+Delete.


On KDE how to change taskbar's font size?

I managed to get to the Settings Window using the systemsettings command.Then, I went to Application Settings and altered whatever i wanted from there including the taskbar.