Wake up from suspend using wireless USB keyboard or mouse (for any Linux Distro)

In terminal:
grep . /sys/bus/usb/devices/*/power/wakeup

The result, for me, was to find out that all usb were disabled.

So now, type:
 sudo su

we have now root privillages.

I have 8 usb ports (you do that for as many usb ports you have) ,so:
 echo enabled > /sys/bus/usb/devices/usb1/power/wakeup
 echo enabled > /sys/bus/usb/devices/usb2/power/wakeup
 echo enabled > /sys/bus/usb/devices/usb3/power/wakeup
 echo enabled > /sys/bus/usb/devices/usb4/power/wakeup
 echo enabled > /sys/bus/usb/devices/usb5/power/wakeup
 echo enabled > /sys/bus/usb/devices/usb6/power/wakeup
 echo enabled > /sys/bus/usb/devices/usb7/power/wakeup
 echo enabled > /sys/bus/usb/devices/usb8/power/wakeup

Go ahead and test it. Now you can wake up from any wireless or wired usb keyboard and mouse.
So then, the reason we must enable all of them, is because in the next step, we will write this in rc.local to execute the command after every reboot, and after reboot some linux distros (maybe all) change the usb ports.
We don't have to worry for anything going wrong by enabling all of them, since linux is in suspend or hibernation, it can't use the wifi to download anything, so it won't wake up without we wake it up on purpose.

Run
 sudo nano /etc/rc.local

and we paste everything from step 2. in there (before the exit 0 of course).

That's it. From now on we can use our wireless usb and mouse to wake up from suspend.
I hope it works for all of you. This guide was made after testing all other possible solutions around the internet.


upgrade from 20.04 to 20.10, will boot to runlevel 3, but not 5

Thanks for the /var/syslog pointer.  I did check that and found:
Dec 14 06:35:10 halibut nautilus[37980]: Could not load a pixbuf from /org/gtk/libgtk/icons/16x16/status/image-missing.png.#012This may indicate that pixbuf loaders or the mime database could not be found.
    Dec 14 06:35:10 halibut org.gnome.Nautilus[37980]: Bail out! Gtk:ERROR:../../../../gtk/gtkiconhelper.c:494:ensure_surface_for_gicon: assertion failed (error == NULL): Failed to load /org/gtk/libgtk/icons/16x16/status/image-missing.png: Unrecognized image file format (gdk-pixbuf-error-quark, 3)

Based on a web search I then performed an apt reinstall of shared-mime-info and gdk-pixbuf2.  My system is working now (w/ nomodeset still, but will get to that).
Thanks again.


Video (Totem) wont play DVD's while others (VLC) can

I just solved this on 18.10 with:

$ sudo apt install gstreamer1.0-plugins-bad

Hope this works for 18.04, too?


How do I fix an error about unclean file system NTFS when mounting?

This problem isn't really related to Ubuntu as it is a Microsoft design decision. However, what you need to do, is configure Windows 8 to do proper shutdown instead of hibernating. The same thing can happen if you have NTFS on a USB memory stick and pull it out without unmounting it first.

It is possible that you can use ntfsfix -d, but it is also possible that this might harm your Windows install, so you need to take precautions if you want to try it.


android USB debugging disappeared and not working anymore

I've been having the same experience:  adb devices was correctly indicating my LG-P705 and now it doesn't.  I have no idea why the change.  This was with Kubuntu 12.04.


In regards to memory usage, what are buffers?

The developers of the linux memory management have a short technical description of it (look for the "Buffer Cache" topic).
Buffers that aren't needed at the moment can make way for more urgent memory needs.
The kernel is using it.
No.


Well, I just missed CouchDB 1.1.1
The problem was buried within an incompatibility with SpiderMonkey 1.8.5. The release notes make that clear. The new version compiles just fine :)


The MD5sum of the server file is 4bd3270bde86d7e4e017e3847a4af485 *ubuntu-12.10-server-amd64.iso and the .ISO is found here http://releases.ubuntu.com/12.10/ubuntu-12.10-server-amd64.iso

according to http://releases.ubuntu.com/12.10/


Why sudo passwd username keeps asking for the current password

I've finally found the solution, but it does not answer why sudo passwd <username> suddenly started asking for the current password, so I am not going to mark it as a solution.

To solve it run as root usermod -p "" mikolaj, and then change the password using passwd as always, and when it asks you for the current password, simply press enter without typing anything.


Lost permissions to install software on ubuntu 1804

i found the solution here: Error instead of password prompt when admin privileges needed.

It had something to do with my installation of x2go....


First of all, you can try to clean some downloaded packages by running commands

sudo apt-get clean
sudo apt-get autoclean

It looks like you mix up / and /boot directories. Software is not installed into /boot directory. But it could run out of place because of kernel image and headers update. You can remove old kernels by using synaptic.

Generally speaking it is not a good idea to make a separate /boot partition. This has no benefits for desktop computers, but may cause problems like you have.

There is no good way to keep kernel images anywhere ele, but /boot. I suggest to merge /boot with /, but it is not quite easy for a novice. Maybe it makes sense to reinstall the system, keeping your /home partition. I guess you have it separate. You can remove /boot partiton and increase / in gparted. You can do it after booting from LiveCD.


The counters are reset like an odometer rolling over after running out of integers. Many device controllers will have different thresholds, but a 0 count does not mean that the drive is without errors, just as a vehicle with 1,000,010km on the odometer is not "fresh off the assembly line".
If you would like to build a graph as seen in Figure 2, you could write a little data collection utility that reads the SMART information off your storage device and records it in a database (or anywhere you see fit, really). The smartmontools package is the one I usually reach for to display storage device info.
You can install it like this:

Open Terminal (if it's not already open)

Install the smartmontools package:
sudo apt install smartmontools

Query a storage medium, for example, an NVMe device:
sudo smartctl --all /dev/nvme0n1

This will give you a lot of information:
smartctl 7.2 2020-12-30 r5155 [x86_64-linux-5.11.0-17-generic] (local build)
Copyright (C) 2002-20, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Number:                       SAMSUNG MZVLW512HMJP-000L7
Serial Number:                      S359NX0K103156
Firmware Version:                   7L7QCXY7
PCI Vendor/Subsystem ID:            0x144d
IEEE OUI Identifier:                0x002538
Total NVM Capacity:                 512,110,190,592 [512 GB]
Unallocated NVM Capacity:           0
Controller ID:                      2
NVMe Version:                       1.2
Number of Namespaces:               1
Namespace 1 Size/Capacity:          512,110,190,592 [512 GB]
Namespace 1 Utilization:            81,254,830,080 [81.2 GB]
Namespace 1 Formatted LBA Size:     512
Namespace 1 IEEE EUI-64:            002538 b181b5c4a3
Local Time is:                      Thu May 27 21:57:29 2021 JST
Firmware Updates (0x16):            3 Slots, no Reset required
Optional Admin Commands (0x0017):   Security Format Frmw_DL Self_Test
Optional NVM Commands (0x001f):     Comp Wr_Unc DS_Mngmt Wr_Zero Sav/Sel_Feat
Log Page Attributes (0x03):         S/H_per_NS Cmd_Eff_Lg
Warning  Comp. Temp. Threshold:     69 Celsius
Critical Comp. Temp. Threshold:     72 Celsius

Supported Power States
St Op     Max   Active     Idle   RL RT WL WT  Ent_Lat  Ex_Lat
 0 +     7.60W       -        -    0  0  0  0        0       0
 1 +     6.00W       -        -    1  1  1  1        0       0
 2 +     5.10W       -        -    2  2  2  2        0       0
 3 -   0.0400W       -        -    3  3  3  3      210    1500
 4 -   0.0050W       -        -    4  4  4  4     2200    6000

Supported LBA Sizes (NSID 0x1)
Id Fmt  Data  Metadt  Rel_Perf
 0 +     512       0         0

=== START OF SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

SMART/Health Information (NVMe Log 0x02)
Critical Warning:                   0x00
Temperature:                        33 Celsius
Available Spare:                    100%
Available Spare Threshold:          10%
Percentage Used:                    1%
Data Units Read:                    20,937,566 [10.7 TB]
Data Units Written:                 26,780,407 [13.7 TB]
Host Read Commands:                 359,002,242
Host Write Commands:                683,010,154
Controller Busy Time:               5,130
Power Cycles:                       1,027
Power On Hours:                     3,812
Unsafe Shutdowns:                   85
Media and Data Integrity Errors:    0
Error Information Log Entries:      719
Warning  Comp. Temperature Time:    0
Critical Comp. Temperature Time:    0
Temperature Sensor 1:               33 Celsius
Temperature Sensor 2:               39 Celsius

Error Information (NVMe Log 0x01, 16 of 64 entries)
Num   ErrCount  SQId   CmdId  Status  PELoc          LBA  NSID    VS
  0        719     0  0x0008  0x4004      -            0     0     -
  1        718     0  0x0008  0x4004      -            0     0     -
  2        717     0  0x0008  0x4004      -            0     0     -
  3        716     0  0x0008  0x4004      -            0     0     -
  4        715     0  0x0008  0x4004      -            0     0     -
  5        714     0  0x0008  0x4004      -            0     0     -
  6        713     0  0x0008  0x4004      -            0     0     -
  7        712     0  0x0008  0x4004      -            0     0     -
  8        711     0  0x0008  0x4004      -            0     0     -
  9        710     0  0x0008  0x4004      -            0     0     -
 10        709     0  0x0008  0x4004      -            0     0     -
 11        708     0  0x0008  0x4004      -            0     0     -
 12        707     0  0x0008  0x4004      -            0     0     -
 13        706     0  0x0008  0x4004      -            0     0     -
 14        705     0  0x0008  0x4004      -            0     0     -
 15        704     0  0x0008  0x4004      -            0     0     -
... (48 entries not read)

This is probably a bit too much information, so you can get just the error counts like this:
sudo smartctl -l error /dev/nvme0n1

The above command returns the same output as seen in the "Error Information" section from the previous command. Note that NVMe devices will return at most 16 entries by default. If you are querying an NVMe device that has more, you can specify the number of entries to return like this:
sudo smartctl -l error,64 /dev/nvme0n1

For my device, there are 64 flash storage chips in total, so I would add ,64 to the command above. You can show information for up to 256 entries.

Hope this gives you a wealth of information to play with and track.


Add "Computer" item to Nautilus sidebar on Ubuntu 17.10

You'll find "Computer" under "Other locations" at the bottom of the sidebar.

Once you have opened "Computer" (/) you can bookmark the location by pressing ctrl+d to make it always present in the sidebar.


I think you can try to edit the images in the /usr/share/unity/folder with your version number..
In my case in Ubuntu 12.04 the versrion is "5", if you have Ubuntu 12.10 the version is "6".

Go to the Terminal and type cd /usr/share/unity/5/ or cd /usr/share/unity/6/
There are 3 icons named launcher_icon_shine_54.png, launcher_icon_shine_170.png and launcher_icon_shine_150.png (I only edited the launcher_icon_shine_54.png image, feel free to edit the 3 files)
Make a backup of this file (or the 3 files) with sudo cp -p launcher_icon_shine_54.png launcher_icon_shine_54.png.bak
Open an application to edit the image, (in my case gimp) to install

In the Terminal type sudo gimp /usr/share/unity/5/launcher_icon_shine_54.png or sudo gimp /usr/share/unity/6/launcher_icon_shine_54.png
You can edit the image according to your needs (I pick the "eraser tool" and delated the all shine mask)
Save your image, logout and login.

Here you have my result:

Before edit the image:

After edit the iamge:

Remember that you have a backup , So if anything goes wrong rename the backup "launcher_icon_shine_54.png.bak" to "launcher_icon_shine_54.png" logout and login to have the original unity.

I hope this would be useful.


Ubuntu 16.04 launcher is missing after installing new updates

After spending so much times and searching, I tested almost all the solutions on the internet.

Problems after upgrading to 14.04 (only background and pointer after login)
Launcher disappeared
Ubuntu 16.04 no menu bar or launcher - help!

But problem didn't solve. Totally the only solution which worked for me was follwing this instruction:

open /usr/bin/ and run gnome-terminal.real
run adduser newuser to create a new user
run kill -9 -1 to logout
login using newuser
do #1 again
run su olduser and enter your password
run mv /home/olduser /home/olduser_backup
run mkdir /home/olduser
run chown olduser:olduser /home/olduser
run reboot
login using olduser

Totally you can delete newuser by running these commands:

sudo deluser newuser
sudo rm /home/newuser -rf


There isn't a way to do it because you cannot log the default user out from WSL.  However, you can create new users then switch to their accounts via sudo su - <username>.


I had the same problem with a computer. I fixed it by selecting COMPATIBLE MODE in the BIOS. It will disable AICH or OICH or RAID and just leave everything as IDE or LEGACY as well as other options in their more compatible modes.


What are unlabeled Ubuntu updates on Phone?

The older system updates in the list are basically irrelevant if you didn't install it. Updates aren't performed automatically. Recently, the updates panel was updated to work a little differently than it previously did, and shows "past" updates. For system updates, this is I think the last available version, and the "updated at" is when it appeared on the server.

Only when you tap on the button to actually perform an update at the top of that window, is when a system update gets installed.


Finding out what caused my laptop to power down

First, check that you have current BIOS in your laptop. Go to the manufacturer's web site to verify.

If your battery is removable, remove it, disconnect AC power, and hold down the power button for 15 seconds. This will reset the power manager. Reconnect all power and see if the problem is resolved.

If your battery is not removable, then disconnect AC power, leave the computer turned on and not sleeping/hibernating, and let the battery drain to zero. Once the computer turns off, hold down the power button for 15 seconds. Reconnect the AC power. Turn computer back on and let it recharge the battery, and recheck operation.


First, press Super KEY and search for Printers.

Then, click Add/Plus Icon

You will see this screen with your connected printer. Select your printer and click next. It will than ask you for a name and ETC ETC. Fill out. It will search the drivers for your printer. You should first search the internet and then from database.

Search in list EPSON
and then select model and apply


I got this same issue when trying to install fglrx or fglrx-updates on my HP dv6-6117 just the other day. I ended up getting it to install by first running:

sudo apt-get install --install-recommends xserver-xorg libgl1-mesa-glx libeg1-mesa-drivers

Just a word of warning, my touchpad was temporarily disabled after doing this and installing fglrx, but it did get fglrx to install.


In defualt Ubuntu 18.04, the .css file /usr/share/gnome-shell/theme/ubuntu.css is the one need to edit..

open the file with below command

sudo -H gedit /usr/share/gnome-shell/theme/ubuntu.css

go to line number around 1726 and find the below content,

.login-dialog-username,
.user-widget-label {
  color: #eeeeec;
  font-size: 120%;
  font-weight: bold;
  text-align: left;
  padding-left: 15px; }

change the font-weight: bold; to font-weight: normal;

save the file, close and reboot to see the change in effect..


Are there issues installing Ubuntu onto Virtuall Box?

Which version of ubuntu you are trying to install?
It seems this error happens when you wrongly make partitions for your OS you want to install.
Please install Ubuntu one time with default partitioning and see if the problem still exist or not! if the OS installed correctly in this way, you are probably doing wrong partitioning.
For default partitioning, in the "Installation type" page, choose the first option:


Sync guest folder to host machine in vagrant

not sure of this specific issue but I use a program called syncthing to sync up my bashrc file over several computers. It will sync between Linux, Windows and Android maybe even iPhone. I also have a sync set up where my photos on my phone are synced to my other PC's so I end up with backups of all the pictures I take without having to remember to copy a photo after taking it.


Press Ctrl+Alt+t for openeing terminal then use -

cat /sys/class/backlight/acpi_video0/max_brightness

it will give you the maximum brightness value, to change it for after booting open-

sudo gedit /etc/rc.local

and add the line shown below before exit , look at the screenshort I have attached-

echo 0 > /sys/class/backlight/acpi_video0/brightness

Change 0 to the maximum value as got from previous command output.

as shown here-

Now just save it and restart. Hope it helped you.


It has been two days without any distortion or glitch on my screen, so I think it is reasonable to say that the problems was solved.
Time to share with the community what I did to get it fixed.
First, the solutions @vanadium suggested decreased the distortions somehow.
GRUB_DEFAULT=0 GRUB_TIMEOUT_STYLE=hidden GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR='lsb_release -i -s 2> /dev/null || echo Debian'
GRUB_CMDLINE_LINUX_DEFAULT="splash quiet iommu=pt i915.enable_psr=0"
GRUB_CMDLINE_LINUX=""

But this solution solved the problem, I created a /usr/share/X11/xorg.conf.d/20-intel.conf file with touch command and inserted these configs:
    Section "Device"
   Identifier  "Intel Graphics"
   Driver      "intel"
   Option      "AccelMethod" "sna"
   Option      "TearFree"    "true"
   Option      "DRI"         "1"
    EndSection


When trying to import Matplotlib.pyplot, get "UnicodeDecodeError"

Thanks for your comments. I've tried Jos' suggestion of adding the following lines to the beginning of tax_rates.py:

import sys
reload(sys)
sys.setdefaultencoding('utf8')

I was happy to see that the script now does run and produces a plot (see below a screenshot from Atom editor).

I would welcome a more 'permanent' solution, though.

P.S. For your reference, the entire tax_rates.py script is copied below.

import sys
reload(sys)
sys.setdefaultencoding('utf8')

import numpy as np
import matplotlib.pyplot as plt

# income = np.linspace(0,2e6,2001)

thresholds = np.array([0, 9725, 37650, 190150, 413350, 415050])

print(thresholds)

plt.figure()
plt.plot(thresholds,thresholds)
plt.show()


I have the same option after upgrading to Kubuntu 15.04.

Fixed by opening the file

.local/share/applications/kde4-kate.desktop

And changing the line:

X-DBUS-StartupType=Multi

to

X-DBUS-StartupType=none

Which fixed the error for me. Got the idea from this post and it seems to be working


Use of /opt and /usr/local directories in the context of a PC

/opt is for third-party applications that don't rely on any dependencies outside the scope of said package. /usr/local is for packages installed on this machine outside the scope of the distribution package manager.

An example:

An open source sip-client supplied as a .deb would install into /usr. If it was built with the Qt framework, apt would pull it in as a dependency.

The same open source sip-client built from source would reside in /usr/localso it would not be messed up by apt if you later installed a .deb package for the same application. You could either build its dependencies from source, or get them from the package manager.

A third-party application in /opt is supposed to be self-contained. For instance, a proprietary sip-client using Qt would not rely on the version from apt, but would have it bundled or statically linked in.

For more information, take a look at the Filesystem Hierarchy Standard.


I would suggest installing deluge, specifically deluged (deluge daemon) and deluge-web (web control panel).

Comprehensive instructions can be found here:

http://dev.deluge-torrent.org/wiki/UserGuide/InitScript/Ubuntu%2011.04%2B%20(Upstart%20Job)


User guide for users migrating from Windows?

Another nice document is the Ubuntu Manual

Although the latest version is written for 10.04, it's still not that 'old' and you can find some interesting information there to help you.

Another very helpful document, if interested as a power user to learn some info on server applications is the Ubuntu Server Guide.


Cant boot into windows after installing ubuntu

The Monitor is saying "Attention 92K/58HZ Frequency out of range." This means the monitor is not able to display the Grub menu as the Grub is sending it in a form that the monitor can't recognize.

Try the following:

gksu gedit /etc/default/grub

Uncomment (delete the # from the beginning) the following line.

# GRUB_TERMINAL=console

Save and exit gedit.

Use the update-grub command:

sudo update-grub

Reboot.

If at any of these setting changes the computer becomes unbootable, you will have to boot from Ubuntu Live CD (Try Ubuntu) and revert the changes in /etc/default/grub in your hard drive.

Explanation:
When you boot the computer first the BIOS loads. Then GRUB loads. At this stage no OS is loaded and the computer has limited graphics capability. By default GRUB assumes the monitor can handle some graphics without the help of CPU, as most modern monitors can.

This monitor is very old and cannot handle the default display resolution of the GRUB menu. So it was showing the error message while GRUB was trying to show the menu choices. Since you couldn't see the menu, you waited till GRUB timed out and loaded the default OS Ubuntu. By commenting out the line GRUB_TERMINAL=console we told GRUB to display the menu in old "text-mode" style that your monitor can display without any help from the CPU.


Your virtual screen is 1600x1600, but you are trying to squeeze two screens into it. Each screen is 1366, so you need virtual screen 2732x768 or bigger.

Option 1.
Remove /etc/X11/xorg.conf and reboot with external monitor attached. Recent X works well without xorg.conf.

Option 2.
Fix virtual desktop size in /etc/X11/xorg.conf.


Ubuntu reinstallation - boot loader device (not UEFI)

Yes, /dev/sda is correct. Grub will handle passing control to the Windows bootloader. I have seen extra windows partitions, but never a specific windows bootloader partition except in UEFI EFI partitions. I may have just not noticed since I don't use the Windows partition much.


How to change Desktop default environment for new users

After creating a user copy .config directory from your home directory to the home directory of a new user.

Enter Files manager with sudo priveligies.

 sudo nautilus

Then Go to /home/user1 directory.Press Ctlr+H to see hidden files. There is a .config directory where user settings are stored.Copy it with right click menu.

Then go to /home/user2 directory. Right click and Paste.

Now log out and enter to the new user account.


What packages in Ubuntu repositories provide BLAKE2 sums on 16.04?

It was a bit difficult, but I found it by looking at the man page:

http://manpages.ubuntu.com/manpages/xenial/man3/blake2.3.html

  Provided by: libb2-dev_0.97-2_i386

so https://launchpad.net/ubuntu/xenial/+package/libb2-dev

But you probably do not want the -dev package, so searching for libb2 got me to

https://packages.ubuntu.com/zesty/libb2-1

so

sudo apt install libb2-1 #I assume, could be libb2

If you are not running zesty , I advise you compile from source:

See https://superuser.com/questions/808553/blake2-installation-in-linux

UPDATE : After further research ...

blake2 was incorporated into coreutils , see https://lists.gnu.org/archive/html/coreutils/2015-05/msg00060.html

So b2sum is part of coreutils

From FEDORA

bodhi@daemon:~$which b2sum
/usr/bin/b2sum
bodhi@daemon:~$dnf provides /usr/bin/b2sum

coreutils-single-8.27-5.fc26.x86_64 : coreutils multicall binary
Repo        : fedora
Matched from:
Filename    : /usr/bin/b2sum

After further searching Ubuntu packages :

https://packages.ubuntu.com/search?suite=zesty&arch=any&searchon=contents&keywords=b2sum

b2sum is available in coreutils starting in zesty (17.04) but not in xenial.


From Software & Updates program open Updates tab
then from option Notify me of a new Ubuntu version select For any new
version

Then enter in terminal:

sudo do-release-upgrade


Speed up workspace switching (no animations)?

... not yet sure if this helps or not (tbd):

(Gnome) Tweaks > Extensions > Workspace Matrix > Cache popup (faster,
consumes more memory


Samba share no longer visible on network

Try commenting out the line

security=share

from your smb.conf file. That's what it took to get mine working again. Don't forget to restart smbd and nmbd afterwards.


how can I revert to previous version of flash?

Here is the fix:

Close running instances of your browser.
If you don't already have synaptic package manager installed (it isn't by default) install it. From the terminal type:

sudo apt-get install synaptic

You will also need to install "hal" and "hal-info", unless already installed:

sudo apt-get install hal hal-info

Start Synaptic Package Manager
In the top right of the application is a search box. Search for "flashplugin-installer"
Highlight the package and press Ctrl + E
The "Force version" window should open
Pick version 11.2.202.243 instead of the currently installed 11.2.202.280
Apply changes by clicking the button that says "Apply" with a check mark under it.
With the package still highlighted, select from the top menu: Package->Lock Version
Close Synaptic and open a terminal
We need to remove old cached versions of the plugin. First type:

 cd ~/.adobe/Flash_Player

Next type:

 rm -rf NativeCache AssetCache APSPrivateData2

You can now close the terminal and reopen your browser

Thanks to Rob S for the instructions on how to do this. The above instructions are his with only slight modifications. Additionally, the last few instructions are from the Arch Linux Wiki.


No sound UBUNTU 20 for dell // i have in setting>HDMI only

Your speakers may be detected as unplugged which causes them to be ignored.

Temporary fix:

sudo apt install pavucontrol
Run pavucontrol
Configuration tab > Profile > Analogue Stereo Output (unplugged) (unavailable)

Speakers should work but it will reset when headphones are unplugged or system rebooted.

Permanent fix:

sudo apt install alsa-tools-gui
Run hdajackretask
Parser hints > jack_detect = no
Apply now
Install boot override


I can't switch "switch to Downloads directory" using bash (I'm new to this)

The solution is that you are logged into the Bash shell as root. The beginning of the cursor line should say your username @ your computer name not root @ your computer name and the end of the cursor should have a $ not a  #. The root account doesn't have a Downloads directory which is why you are getting the error.

If this is the case you can type exit and press enter  this should bring you back to where it will have your username@yourcomputername and the $ at the end. If all else fails you can close Bash and open it again and it should start you in your user's 'home' directory.

Once set this way, typing cd ~/Downloads (in Ubuntu/Linux it is case sensitive) will bring you into your Downloads directory. The Bash shell mirrors the Windows drive structure. The downloads folder is the same folder as Windows default download folder ... C:/Users/yourusername/Downloads

The original poster was having problems with the bash shell always using root. I have tried everything to get the initial screen back where you enter the Unix user name and password but wasn't able to find a way without breaking the shell.

The way I was able to get back to that initial setting was to create a new Windows account. Log into that account and then reboot

note I had to log in and let it set up the account then I had to reboot because some of the files needed for the bash didn't seem to be in place and it seemed to hang when I tried but the reboot solved that.

Then I launched a cmd prompt and type bash to get the following screen.

At this point I screwed up again... I picked the name Don for the UNIX name and put in a password .. everything worked well until I tried cd ~/Desktop and it threw an error.

The error said

bash: cd: /home/don/Desktop: No such file or directory

If you notice in the image the user directory for this account I created is donat not don .. so the ~/Desktop is using the "username" to find the directory

Because of this I would have had to use donat as the Unix name for everything to work properly.

So if you have to create a new account to set this up properly .. Make sure you make note of what directory that new account is using and make that your UNIX login name matches the directory name.

As I said, if I look at explorer  and look at the path C:\Users\ the "Home" folder is donat for this account.

Under further messing around I found that it seems that Windows and the Bash running in Windows doesn't like the ~/directory shortcuts. You will have to use full paths such as /mnt/c/Users/username/Downloads to access your download folder you can't just use ~/Downloads.


Kernel Panic, Can I get specific info from this screenshot I have?

If it happens on both Linux and Windows, it's almost certainly faulty hardware. Have you done a memtest, for starters? (Boot Ubuntu desktop CD, choose "test memory".)


Don't use the PPA, install vlc from the Ubuntu repositories.

Remove the PPA you have installed:

sudo add-apt-repository --remove ppa:videolan/stable-daily

Empty the package cache:

sudo apt-get clean

Update your package lists:

sudo apt-get update

Downgrade/install all vlc packages to/in the repository version:

sudo apt-get install --reinstall vlc=2.1.2-2build2 vlc-data=2.1.2-2build2 vlc-nox=2.1.2-2build2 vlc-plugin-notify=2.1.2-2build2 vlc-plugin-pulse=2.1.2-2build2

Depending on your Ubuntu version, you might currently (Nov 20, 2015) get a VLC version up to 2.2.1-3 on Wily (15.10). Older Ubuntu versions might have older VLC versions in their repositories.

You check the versions available for you with the command:

apt-cache policy vlc

An example output on my 15.10 64bit system would be:

vlc:
  Installed: (none)
  Candidate: 2.2.1-3
  Version table:
     2.2.1-3 0
        500 http://[YOUR REPOSITORY SERVER URL]/ wily/universe amd64 Packages


Ubuntu is not detected after installing with Windows 7

Before you start messing with the boot loader or grub of either OS try booting to windows and press the windows key + R  type msconfig in the command box and hit return.
Click on the Boot tab check to see if Ubuntu is listed as an OS. If it is try making the Ubuntu installation the default (select Ubuntu 14.04 and click on the set as default button). Try to reboot into Ubuntu.

This would just be my first step. If this does not work get back to me.

As a side note:- Your D: drive going missing could be a few things but you have one of the most versatile tools in your Ubuntu USB. Just to see if the drive does still exist boot into Ubuntu Live using the USB and check the file structure of D: if it's still available try mounting it from your Ubuntu Live USB (at the worst you will get to save any data).


android phone not showing up when connected

Try using these steps:

Visit the detect Android phone on Ubuntu page and follow its directions
Change the USB PC connection in your phone from Media device (MTP) to Send Images (PTP).

I agree its not the regular practice, yet it worked for me quite well. Try if it helps else will try solving it in other ways possible.


Software Updater Ignores request to update

You should install the updates manually. Maybe this is a problem, that will be fixed by on of these updates.

sudo -s
apt-get update
apt-get dist-upgrade-y

Please keep in mind, that 12.10 will be EOL in april.


This has already been answered - Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?. Just run:

sudo fuser -cuk /var/lib/dpkg/lock; sudo rm -f /var/lib/dpkg/lock


Setting Firefox hot keys to be like in Windows

There is a KeyConfig extension. it seems to be the least painful way to assign shortcut keys.

See this page: Change Firefox Keyboard Shortcuts

Although it does not contain preconfigured bindings for Windows.


Intermittent `Error: cannot open display: localhost:10.0` with Vagrant

I have answered the related question over on stack exchange:

Intermittent Error: cannot open display: localhost:10.0 with Vagrant

In short, use -Y in the ssh config and you'll be ok.


No Networking Lubuntu 14.04 on iMac G5 PowerPC

Your wireless device requires proprietary firmware. However, without ethernet and therefor internet access, we will have to get the firmware off-line. Please download the b43.zip package on some other computer and transfer it on a USB key or similar to the Ubuntu computer's desktop: http://ubuntuforums.org/attachment.php?attachmentid=229272&d=1356748832

Right-click it and select 'Extract Here.' Now, in the terminal:

sudo mkdir /lib/firmware/b43
sudo cp ~/Desktop/b43/* /lib/firmware/b43

Reboot and the wireless should be working.


Install and run Java app on Ubuntu 14.04 issue

Sometimes openjdk doesn't work but oracle java does. Try installing it with:

sudo add-apt-repository ppa:webupd8team/java

and then run

sudo apt update&&sudo apt install oracle-java8-installer

If this doesn't work then the software might not be compatible and you might want to try different versions or other software


Can't boot into Windows 7 after installing 11.10

A quick fix for many dual boot problems is updating your Grub (Grub is the bootloader - GRand Unified Bootloader)

Try this:

Open a terminal by pressing ctrl+alt+t or open your unity dash and start typing "terminal"
Type/copy:

    sudo update-grub

That should add the windows entry, let us know if not and we'll try some other options.

grub-customizer is a good gui package to use, but this should do the same automatically.


If you only have one NTFS partition then use the Use Whole Disc option on the ubuntu installer.

Your question suggests you have more than one NTFS partition. If this is the case - perhaps data - then formatting all partitions will lose that data.


If you search the following in to google:

MPEG-4 AAC decoder download
H.264 decoder flv download
VLC media player download

and all the other ones with download on the end.Then insert a USB/CD (They will both work) Then when it prompts you to download the file click 'Save'. Then it will ask you where. Save it in your CD/USB. Then go to your computer and insert your drive. Launch the files and you are up and away!


Ubuntu 15.10 removed Gnome 3 - broke unity

First off you need to resolve the issue with the held broken packages, see this Unable to correct problems, you have held broken packages then proceed with the below

Install the ubuntu-desktop package. This should install everything necessary for the 'normal' Unity experience.

sudo apt-get install ubuntu-desktop

If that doesn't work, you can try reinstalling all the dependencies of ubuntu-desktop with

sudo apt-cache depends ubuntu-desktop | grep '[ |]Depends: [^<]' | cut -d: -f2 | tr -d ' ' | xargs sudo apt-get --reinstall install -y

Command borrowed from: Reinstall package and its installed dependencies


Can't connect with SSH to Ubuntu server (20.04) on raspberry pi 4

By logging in successfully on your LAN, you have conclusively demonstrated that your Pi+Ubuntu server is configured properly.
All of the devices on your network share a single public IP address -- the router's IP address.
When you try to ssh into your network from outside, those packets reach the router first. Set up port forwarding on your router, so the router knows that the ssh connections should be sent (forwarded) to the Pi.
It's a router setting that has nothing to do with the Pi or with Ubuntu, nor with the Ubunbtu Server's firewall.


If you are having the same issue I have, and it sounds like you do, try unchecking Allow the window manager to control the windows in the Graphics section of winecfg. Works for me, no Dash or titlebar in fullscreen.


Broken icon means that there is a problem with the path of the image you are trying to set.Your code is correct. It just can't find the image you want to use thus a broken image is displayed instead.

 image = gtk.Image()
    image.set_from_file("/home/your_username/path/to/your/image.png")

In order to prevent mistakes from wrong paths, I suggest browsing with Nautilus at the image you want to use, right click on it -> Properties - > Basic : Location


According to this post in ubuntu forums, it seems that moonlight is the only alternative, and it isn't actively developed. sorry :(

http://ubuntuforums.org/showthread.php?t=2029336


How to create custom repository on Ubuntu 14.04

Installing  apache :

sudo apt-get install apache2

Creating needed directories

Create a directory inside the webroot /var/www/

let's say name it repo.

sudo mkdir /var/www/repo

Now under repo you should create a directory for each architecture you want to use if you want more than one architecture.

For here i'll use amd64 for my 64bit systems. So, let's create this directory:

sudo mkdir /var/www/repo/amd64

Creating Packages.gz file

use the command dpkg-scanpackages

cd /var/www/repo/
sudo dpkg-scanpackages amd64 | gzip -9c > amd64/Packages.gz

Add the new repo

sudo -H gedit /etc/apt/sources.list.d/custom-repo.list

then add the line:

deb http://Your_Systme_IP/repo/ amd64/

Finally, update sources list:

sudo apt-get update

Now whenever you try to install any app, if you have its debs in your local repo then you install from it else then going to install from Internet.


Open the terminal and type:

sudo apt update
sudo apt upgrade
sudo dpkg --remove --force-remove-reinstreq snapd
sudo snap install core
snap find vlc

Results of snap --version on Ubuntu 16.04 with an updated Linux kernel installed:

:~$ snap --version
snap    2.31.2
snapd   2.31.2
series  16
ubuntu  16.04
kernel  4.4.0-119-generic


problem with tp_smapi on ubuntu 15.4 lenovo thinkpad e440

In these comments, someone had the same problem, and apparently he found a solution. It didn't work for me though. Maybe for you it does.


How to replace Mutter with Compiz to enable Wobbly effect?

From the Gnome 3 Myths page:

I can't use Compiz with GNOME Shell!
Because the GNOME Shell project wanted "tighter integration" between the panel and window manager than cooperating with the Compiz project would allow, this could actually be true. This mailing list post has more information.

Gnome Shell relies on Mutter to do its fancy work, just as Unity (3D) relies on Compiz. You can't mix and match unfortunately.
This might get fixed in time but I wouldn't hold my breath.

Gnome Classic does work with Compiz though. If you're happier with a panel-based setup and want the wobblyness, you can turn compiz on by running compiz --replace.
To turn on wobbly windows, I suggest you install compizconfig-settings-manager and then run ccsm to change the compiz settings. A word of warning: CCSM is a powerful tool without any safety latches. It's quite easy to break Compiz with it so if you do ever get stuck, you can reset your settings by running:
gconftool-2 --recursive-unset /apps/compiz


Configuring .desktop Launcher (switcher problem)

For darteditor.desktop, I'm using:

[Desktop Entry]
Version=1.0
Name=DartEditor
GenericName=Text Editor
Exec=DartEditor
Type=Application
Terminal=false
Icon=/home/richardworley/dart/icon.xpm
Categories=TextEditor;IDE;Development
X-Ayatana-Desktop-Shortcuts=NewWindow

This is working with Alt+tab and minimizing to the sidebar.


How can i install my Lexmark X4530 into my ubuntu 12.04?

Lexmark printers are not well supported for Linux.

According to Lexmark Driver Support for Linux OS:  A Linux driver is not available for this printer.


You can just boot with a Ubuntu live CD (or USB), and resize everything with gparted.


In the sound settings, check what device is selected in 'Play sound through'. It should be 'Built-in Audio' and nothing like 'HDMI sound', etc.

If it is, change the default output device to 'Built-in Audio' and restart.


You can add the MAAS IP to /etc/resolv.conf as a nameserver, but that will get overwritten eventually. How to make it permanent depends on how your network is setup and is out of scope for this question. But it should get you going for now.

Alternatively, and temporarily (because the IP will change), you can also just add the node4.maas name to /etc/hosts with its IP. That IP you can get in the MAAS node listing page and clicking on the node name, or by running "dig @ +short node4.maas".


How to add Wanda (the fish) to the GNOME Shell panel?

Indicator-fish:

You can use indicator-fish. It is packaged for 11.04, so if you add the PPA, edit the source entry to point to "Natty". Or, you can build from source, or download the package from the PPA manually. It works in Unity and GNOME Shell.

An example of what it says:

  (It really is isn't it?)


malloc() allocates memory from the heap, which it manages.  It very well may return a chunk of heap that was previously used and then free()ed, and so it will still contain whatever data was there before.  When there is no heap yet, or not any free, it has to obtain more ram from the kernel to enlarge the heap.  When the kernel gives a new process more ram, it makes sure to zero it all out first, lest one process be able to capture and examine data freed by another process, which may contain sensitive information.  Thus, what you are likely seeing is the first time you malloc() any memory, it is coming straight from the kernel and is thus zeroeod, rather than being reused heap within the process, which would not be zeroed.


how to fix error ./configure error configure: error

libzmq-dev does not contain libczmq. Note the extra "c".

libczmq is a different library that apparently is not packaged for Ubuntu. Its web page says that for Ubuntu:

Installing ZeroMQ and CZMQ from source code is recommended.

Further down the same page you will find instructions how to do that.


Trapped in the Notes field: Is there no KeePassXC "OK" keyboard shortcut?

For me, the OK button's O is underlined:

This suggests that it is a keyboard accelerator for that button, and pressing AltO works for me.


How to get accurate colors and contrast in Ubuntu?

Start nvidia-settings and navigate to:

X Screen 0 » X Server Color Correction

Change the settings and don't forget to change the configuration. That's all.


GPU's model can be shown by this package mesa-utils

type this in your terminal sudo apt-get install mesa-utils

Do you have only nvidia's GPU? (comment below please so I can edit this post! ;) )
If you have switchable GPUs, and are using bublebee I recommend do not try to change anything in your system. If not try and install mesa-utils

and also see this http://mygeekopinions.blogspot.co.uk/2011/06/how-to-install-nvidia-2750907-driver-in.html


Ubuntu 18.04 does not show dock icons for older X11 applications

Each icon you see in the Applications overview corresponds with a .desktop file that provides the shell with various information on the application, including the name to display in the menuing system, how the program should be launched, and obviously also what icon should be used to represent the program. These files are merely text files. The information on what icon to use is provided on the Icon= line. There, you can specify either the full pathname (i.e., folder and subfolders + name) of any compatible graphic that you want to be used as an icon or only a file name. In the latter case, a valid icon file is looked for in some standard folders. If no icon is specified, or no valid icon is found, a fallback icon is used.

Thus, you should check the corresponding .desktop file, and ensure that 1) there is a line for the Icon and 2) it points to an existing valid file.


Missing install file, any other way to get it?

./pool/main/g/grub2-signed/grub-efi-amd64-signed_1.9~ubuntu12.04.3+1.99-21ubuntu3.9_amd64.deb

I find that in the iso file

the file name  is:
"grub-efi-amd64-signed_1.9~ubuntu12.04.3+1.99-21ubuntu3.9_amd6.deb"

we wanted:
"grub-efi-amd64-signed_1.9~ubuntu12.04.3+1.99-21ubuntu3.9_amd64.deb"


Can Ubuntu use multiple devices for downloading?

If you are looking for integrating multiple network connections, ISPUnity may help you out.

Have a look at this blog article to get started.


I'll tell you what eventually worked best for me.

Open the gnome preference "keyboard layout" pane
Move the layout order, if you have more than one
Delete all layouts except the default one (mine was a US layout)

The previous two steps have been suggested as fixes on their own (on the Ubuntu forums?). They did not work for me. I tried them together consecutively and this again did not work for me. Thus my next step.

Press, "Reset to Defaults"
Layout changes effectuated from both the layout pane and indicator now result in a change in layout.
Of course, add layouts back before attempting to change to them. Use the preview function to find a layout that easily produces the diacritical marks you seek.

I think my problem was from the fact that some of the layouts had changed in name, at least that's my take considering that the layout names weren't exactly what I expected when reassigning them. Deleting my extra layouts and then assigning new ones from a fresh list seems to have circumvented my issues, that being that the layouts of my choice now point to existing layouts with names to match.


How can I see what icons on the launcher are actually doing?

For globally installed applications, the .desktop file can be found in /usr/share/applications.  For custom applications you will need to look in ~/.local/share/applications.

Nautilus seems to drop the .desktop off the filename in all view modes that I tried which is confusing.  It's probably best to look at the contents of the file with cat.

Eg.:

cat /usr/share/applications/xyzprogram.desktop


qt5 error on setting the CMAKE_PREFIX_PATH

It's probably

cmake -DCMAKE_PREFIX_PATH="$HOME/Qt/5.5/gcc_64" my-src-dir/


As explained by Gilles's answer on related question this tends to occur of the last command doesn't return an exit status, and therefore you may want to run it as compound command:

{ sleep 1; poweroff ;}

or as subshell

( sleep 1; poweroff ;)

Consider using alternative solutions also provided on the linked post.


How do I access phpMyAdmin on localhost with NginX

1.While installing phpmyadmin, select apache2 and install it, it copies necessary files.

2.Nginx use /var/www/html/ for default web server root. so use ln -s /usr/share/phpmyadmin /var/www/html.

3.If you changed web server root, istead of /var/www/html, use your path and make sure you set the right permissions.

4.open your browser and open localhost/phpmyadmin, you should open phpMyAdmin.


You receive the error because php5 is outdated.

Execute : sudo apt-get install php7.0-imap


After Installing Unity I get Unity Style Notifications in KDE?

This happens because you have multiple notification services installed simultaneously.

Unfortunately, dbus doesn't seem to be able to intelligently select the appropriate notification service, so you will either need to disable one of the services (as detailed in this answer), or, if you want to keep both notify-osd and KDE's Plasma notification service installed and enabled, you will probably need to resort to a cumbersome workaround.

N.B: If you opt for the workaround you will need to adapt the shell script in Step 3 to

detect when either KDE or Unity is running
run /usr/bin/plasma_waitforname org.freedesktop.Notifications when KDE is running


Simple solution:

apt-get remove ubuntu-desktop gnome-session-*
apt-get update
apt-get install gdm gnome-session gnome-session-bin gnome-session-canberra gnome-session-common gnome-session-flashback gnome-shell-extensions nautilus-share ubuntu-desktop


I suggest you to run a live version of ubuntu (on an usb stick, for example) and run gparted. Then decrease the size of the partition 5 or 7, so you can increase size of partition 6. Backup before doing so!

Also a real quick search can easily get you some nice tutorials. Here's what I found in less than a minute:

How to Resize Your Ubuntu Partitions | How To Geek
Modify Your Partitions With GParted Without Losing Data | How To Forge


How do I compile a c program made in sublime text?

Typically you just run gcc filename.c and that'll generate an a.out executable. As a shortcut, you can also run make filename and it'll create a binary with the same filename (without the extension). By example:

$ cat helloworld.c
#include <stdio.h>

main() {
    printf("Hello, world!\n");
    return 0;
}

$ gcc helloworld.c
$ ./a.out
Hello, world!

$ make helloworld
cc     helloworld.c   -o helloworld
$ ./helloworld
Hello, world!


Alt key in Autodesk Maya 2011 using Gnome

Ok, I'm such an idiot :)

All I had to do was restart Maya after setting Preferences -> Windows -> Movement Key and set it to Super. Now you drag your windows using Super + click, and in Maya your ALT key behaves as expected.

I was about to delete this question, but I will leave it in the system, just in case someone into the same error...... Cheers!


how to redirect output to a log file without tee? normal redirection is not working

You have redirected stderr to stdout (the terminal), then you've redirected stdout to a file. In conclusion, you haven't redirected stderr to the file:

stderr -> stdout, stderr goes to the terminal.
stdout -> $logfile, stdout goes to the $logfile.

Try using the following:

application >"$logfile" 2>&1

Notice the order matters:

stdout -> $logfile, stdout goes to $logfile.
stderr -> stdout -> $logfile, stderr goes to stdout which is the same as $logfile.


No, that is not the way Ubuntu handles software. 14.04 was created with Tomcat 7 and shall remain that way. It will never be included in the default software of 14.04. Tomcat 8 was included in Utopic = 14.10.

If you want newer software in 14.04 you will need to install it yourself by downloading the installation software from the Apache site. There are lots of tutorials on how to do this.


Ubuntu touch how to get HTML 5 app template running?

Two days later I found the answer myself. I kind of made the problem up by myself. But may be the answer will help others.

When creating a new project one is asked for the corresponding framework. I simply used the default value "Ubuntu core 15.04" but I have to change it to 14.04. Now everything works quite well.


There is no command like this:

$ apt-get install update
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package update

Any arguments given after install will be taken by apt-get as a package name. But since there is no package update, it will fail.


I finnaly found a solution, after trying tons of software here's what I did, installed Rufus on a friends laptop which had windows 10 and used it to make the iso work perfectly.


Where can I find a complete list of packages that I have installed after initial installation?

Open the ISO CD image file with file-roller and extract the file:
casper/filesystem.manifest-desktop
It contains all packages that are installed after the installation.
Just keep in mind that you can also download updates and closed source software during the installation, so you'd have the check for those packages separately.
Ubuntu 12.04
In Ubuntu 12.04 the list is no longer available in a single file. Instead, you you need to unpack two files:

filesystem.manifest
filesystem.manifest-remove

and remove the packages in the latter from the former:
comm -3 <(cat filesystem.manifest | awk '{print $1}' | sort) <(cat filesystem.manifest-remove | sort) > default.txt

You can use this as basis to figure out, what has been added since the install (see this answer for details).


nmcli device wifi hotspot con-name <Name of interface> ssid <NameOfYourHotspot> band bg password <YourPassword>

It requires network-manager installed and being connected via ethernet.


How to disable the Keyboard Layouts Choosing screen in Gnome?

I don't know how to disable that feature, but there may be a workaround.

You can install gnome-tweak-tool and then search for and open Tweaks from the Activities overview. You'll find a GUI for setting an alternative shortcut for input source switching at Keyboard & Mouse -> Additional Layout Options -> Switching to another layout.

AFAIK, that window does not pop up when using such an alternative shortcut.


Deepin Software Centre unable to aunthenticate password

Its asking for the root password which is disabled by default. To set the root password use sudo passwd and set it. Then enter it when Deepin prompts for it.


How to debug Unity? (It works from live CD, but it doesn't work after update...)

I've found out the solution. It is related to a NVIDIA's driver problem.

Looking for messages in /var/log/syslog, I've discovered an error message from which I've taken the main words:

segfault error 4 in libc-2.15.so compiz

A search on Google and I've found this post:

Compiz crashes with SIGSEGV after upgrade to 12.04

http://ubuntuforums.org/showthread.php?t=1966002&page=2

So, the problem is related to NVIDIAS's proprietary drivers. (There are two options from Additional Drivers, none of them works...) Disabling them brings me back the normal Unity, which unfortunately runs slowly, for obvious reasons. That's why I don't get this problem when I use the live usb: the proprietary drivers are not enabled by default.

Now, we've got to wait NVIDIA fix this issue...


Deleted my /usr/ directory, recovered with chroot now getting a Segmentation fault (core dumped) trying to run Sudo

You will never get this right by trying to put files back. You will learn a lot by trying.  Launch a reinstall and let it go.


No, CCSM can still wreck your desktop configuration

MyUnity is the commonly recommended "power user" configuration tool as of 12.04. Instructions on its use can be found here.


Disable tab preview / thumbnail on bottom panel? - Ubuntu 20.04 Mate

right-click on the three vertical dots right before the Firefox icon in your panel (see the following screenshot).

Click Preferences.

In the menu that will open, select the Hide thumbnails on hover option (see the following screenshot) and close the menu.


How can I free space from a massive 39.5GB /var/log/ folder?

You must not remove the entire folder but you can remove "Old-Packed" log files without harming your system.

For a typical home user, it's safe to remove any log file that is compressed and has a .gz extension (as you can see in the picture).

These compressed log files are old logs that are gzipped to reduce storage space, and as an average user, you don't need them.


Problem with partitions (deleted all of them)

Then, after several tries, I somehow installed Ubuntu and have been working on it since.

That was a terribly bad idea. You should never, ever install a new OS on top of an old one you are trying to rescue.

Moreover... your screenshot shows that you managed to fill up ~600GB of stuff on the hard drive, which makes any recovery impossible.

  I want to delete the current Ubuntu that I have and start working on the computer like it didn't have any operative systems (install both Windows and Ubuntu from scratch).

Mmm ok, this is kind of the opposite of what the title would suggest. If you don't want to recover stuff, but instead you want to completely erase the data on the disk, it's quite easy. You have two ways.

WARNING: Everything written in the following part of my answer will delete or at least seriously damage the contents of your hard drive. Don't use the following commands if you care about the data contained there. I am not kidding.

Having said that, let's start:

The basic way

If you want your disk to "seem" empty, you can delete the partition table. For doing so, you can just blank some blocks at the beginning of your disk:

# DANGEROUS COMMAND, BE CAREFUL
sudo dd if=/dev/zero of=/dev/sda bs=1024 count=10

I've put up some numbers. Probably just one or two blocks could be ok, but just in case...

As said before, this will blank the partition table. This allows to see the disk as empty, however it doesn't give you a guarantee on security. What I mean is that people will still be able to recover most of your files by using specialized computer forensics software such as testdisk, photorec, foremost or the Autopsy Browser.

The long, long way

Another option is to completely wipe every single bit on your hard disk. This can be done by not limiting dd. It's also useful to try a bigger block size to save a bit of time.

# EXTREMELY DANGEROUS COMMAND, BE EXTREMELY CAREFUL
sudo dd if=/dev/zero of=/dev/sda bs=8192

This could take up to some hour without giving you any feedback.

Final remarks

It is your responsibility to make backups of data you need. You asked for ways to wipe your disk and I gave them, but keep in mind that taking care of your data is your duty.


Application lens installend but missing in dash

After a lot of trial and error I found out it was something (still don't know exactly what) in .cache/software-center. I think I should report it but I don't know to whom (ideas?). Anyway, if someone is interested let me know and I'll send the infamous directory. Thanks to everyone that read this :)


How can I make a permanant change on a persistent live USB?

Make a Permanent Change on a Persistent Live USB
Programs like Etcher, Win32DiskImager, dd, Gnome-Disks and Startup Disk Creator, create a USB with a read only operating system with a read only bootloader.
Other Programs like Rufus, Ventoy, mkusb, UNetbootin and YUMI create a USB with a Syslinux or GRUB bootloader config file that can be edited regardless if the USB is Persistent or not.
Rufus Windows:

If you are working from Windows, use Rufus to create your Live or Persistent USB.
Use the Write ISO image option, (Default), if asked.

While still in Windows Edit /boot/grub/grub.cfg. adding radeon.modeset=0 after quiet splash in the first menuentry.

Then Edit /isolinux/txt.cfg adding radeon.modeset=0 after quiet splash in the first menu item.

Mkusb Ubuntu

If you are working from Ubuntu use mkusb to create a persistent USB with your preferred options.

Using disks, mount the USB's usbboot partition.

Edit /boot/grub/grub.cfg. adding radeon.modeset=0 after quiet splash in the first menuentry.

This should set you up permanently for both BIOS and UEFI boots whether the USB is Live or Persistent.


How to change a LibreOffice Impress presentation from 4:3 to 16:9 ratio?

For Version LibreOffice 5.1.2.2.
- Select menu option "Slide"
- Select "page/slides properties.."
- Select folder "Page" and "Paper format" options.


How to show the latest bzr revision number of a branch

It could be achieved by bzr revno

See http://doc.bazaar.canonical.com/latest/en/user-guide/version_info.html for more information.


how to fix the installation of new linux kernel?

Boot into a live USB and do this

sudo mount /dev/sda1 /mnt
sudo grub-install --root-directory=/mnt /dev/sda


The output of uname -r depends on the topmost Makefile of your kernel source. You can edit it. For example, the Makefile in your case would look like this.

VERSION = 4
PATCHLEVEL = 2
SUBLEVEL = 0
EXTRAVERSION = -37-generic

You can change the EXTRAVERSION field, to change the output of uname -r


Custom libinput quirk for Apple Magic Trackpad 2

The issue is solved.

You can't change default quirks. So you need to create /usr/share/libinput/local-overrides.quirks (with this particular name) and specify the desired config there.

AttrTouchPressureRange is incorrect attribute name (despite that it's the name given in official docs https://wayland.freedesktop.org/libinput/doc/latest/device-quirks.html#device-quirks). The proper name is AttrPressureRange, I had to check the following docs page: https://wayland.freedesktop.org/libinput/doc/latest/touchpad-pressure-debugging.html#touchpad-pressure-hwdb.


Resizing a window freezes the entire system

I see you commented on your own question.  Just wanted to give you some options:

You can install 2d-unity as a work-around:

How do I install and switch to the Unity 2D desktop?

Then you choose it from the login window as "2d Unity", I think.  This will look nearly the same as the default ubuntu desktop, but without 3d acceleration.

Also, you may want to file a defect in launchpad if you can reliably reproduce the crash.  If you really feel like narrowing it down, you could open up "CompizConfig Settings Manager", and try turning of some features like "animations" or "fading windows" and see if one of those features is causing the crash.


Cant access Windows 7 after dual-booting with Ubuntu

My Hypothesis

I'm 95% certain that you've accidentally trashed your Windows installation. Evidence:

  Following some online instructions, I chose the "Something else" option. I created 4 partitions from apparently "free space" (although my Windows partition was located there)

The "Something Else" option shows the disk and all current partitions. If it misidentified the disk as being empty when in fact there were current partitions, then you could easily trash your installation in this way. In fact, there's a known bug in libparted (upon which the Ubuntu installer's partitioner is based) that causes it to show the disk as empty when the partition table deviates from absolute perfection. The most likely explanation is that you started with a GPT disk but installed Windows in BIOS mode, which would have caused a GPT-to-MBR conversion that left some GPT data intact. This confuses libparted, resulting in the "blank disk" problem. See this page of mine for details and a fix (which will no longer work for you -- by setting up new partitions, you're long past the point where it can be fixed).

Incidentally, I tried looking for a bug report about this on Launchpad (Ubuntu's bug-tracker), but didn't find one, which is surprising. Perhaps I'll investigate further and file a bug report, since this problem is so serious.

  Ubuntu installed fine, but after restarting my computer, it booted directly into Ubuntu, without displaying the GRUB bootloader menu that I expected.

This behavior is consistent with a completely trashed Windows, although there are also other possible explanations.

  Using my Windows 7 laptop, I created a system repair disc and booted my computer from it. Strangely it displayed an error message that the disc "was not compatible with my version of Windows." This does not make sense as both my desktop and laptop are 64-bit versions of Windows 7.

This is also consistent with my hypothesis, although again, there are other explanations. Note that the "compatibility" in this quote refers (or can refer) to the partition table type -- Windows ties the Master Boot Record (MBR) partition table to a BIOS-mode boot and the GUID Partition Table (GPT) to an EFI-mode boot. If the Windows installer boots in BIOS mode and sees a GPT disk, or if it boots in EFI mode and sees an MBR disk, it will refuse to do anything with the disk, except (in some circumstances) to repartition the disk and re-install.

Further Diagnoses

To test my hypothesis, you need to examine your partition table. You can do this with GParted, parted, gdisk, or other tools. The easiest and best for the moment is parted:

$ sudo parted /dev/sda print
Model: ATA Samsung SSD 850 (scsi)
Disk /dev/sda: 250GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system  Name                 Flags
 1      524kB   1573kB  1049kB               BIOS boot partition  bios_grub
 2      1573kB  580MB   579MB   fat32        EFI System           boot
 3      580MB   1106MB  525MB   ext4         Xubuntu /boot
 4      1631MB  250GB   248GB                Linux LVM            lvm

The output of parted /dev/sda print will show your partition table. The Partition Table: line shows the partition table type -- GPT in this example. (MBR shows as msdos.) More important is the details of the partitions. If you see one or more NTFS partitions, then I'm probably wrong and Windows may be intact. If you see nothing but Linux partitions (ext4fs, Linux LVM, etc.), as in this example, then my hypothesis is correct. (Note that the FAT32 partition in my example is an EFI System Partition (ESP), which holds boot loaders for all OSes.)

If you need help interpreting your partition table, please cut-and-paste the output of parted to a pastebin site and post the URL to your document here.

Fixing It

If I'm right, you can't fix the problem -- at least, not completely. The best you can do is:

STOP USING THE INSTALLED OS IMMEDIATELY! Every moment you use the computer from its on-disk Ubuntu is another moment in which Ubuntu may write data over the remnants of your personal files on the hard disk.
If you don't already have one, buy a disk to use for data recovery. An external disk big enough to hold all your personal files should do fine.
Boot to an emergency disk (like the Ubuntu installer in its "try before installing" mode). A good case can be made for Windows emergency tools, too.
Run PhotoRec or similar software. These tools enable you to recover individual files, even from an overwritten filesystem -- which is what you've got. I've seen claims that some Windows tools can do a better job at recovering files from an overwritten NTFS partition than PhotoRec can, but I don't have specific program names or URLs. Note that you'll need to recover files to another physical disk -- hence step #2. Also, you're unlikely to recover all your files, and you may spend hours sifting through the files you recover to properly organize them. You may end up with a bunch of Windows program files, which you can throw away -- it will be easier to re-install Windows and your programs than to try to use those individual program files.
If you want it, re-install Windows. This will require learning about EFI vs. BIOS boot modes. You may want to read this page of mine on the subject, which may help you navigate this minefield. (Note that BIOS/CSM/legacy boot issues may have been part of what set you on the path to this problem, but the most important issue, if my hypothesis is correct, was the bug in libparted.)

This procedure assumes that, like most people, you lack good backups. If you've got good backups, you can restore your personal files from them with much less fuss.

Update

I just did some tests, and it looks like the bug that I think bit you has been fixed in Ubuntu 15.04. I'm pretty certain it was present in 14.04.


Manage Apks on Linux - rename, icon version


Install a FTP server on you android device and connect via FTP client from your PC. It's the only reliable way that I can connect after the Jellybean update (HTC One X, international version).

And HTC wonders why sales are down...


problem enabling wireless and wired networking at the same time

You cannot have multiple interfaces on a computer in the same subnet. This can cause routing issues and loops. And if you have an intelligent switch which recognizes it, it will shut down one of your interfaces.
So you need to keep all your interfaces on separate subnets.


Printing accented characters on the terminal

Assuming your terminal emulator is already able to display accented characters properly using a given encoding you should configure the JVM to use that encoding.

This might be the proper way:

export LC_ALL=en_US.UTF-8
java yourApplication


Seeking system architecture advice for Ubuntu Server home server and OpenELEC media center

If your file server is powerful enough just run any recent version of Ubuntu and install XBMC over the top and set it to start up when it automatically logs in. OpenElec while it is nice and lean it has zero to little ability for command line or background configuration (doesn't even have access to apt-get)


16.04: Problem installing LAMP and wordpress

vi (and vim) show a ~ at the beginning of empty lines.

This (and the [New file]) show that you have a new, blank file in which you're supposed to write your WordPress configuration.

Start writing by Pressing Insert (or the i key). When you are finished, just press Esc to enter Vi's command mode, then press type :wq and Enter to save and exit (wq stands for write, quit). To save and not quit, type :w instead of :wq and press Insert (or i) to get back to writing.

Though if you have a GUI, I recommend Gedit (or for root access, gksudo gedit) for editing files, since it's a lot simpler than Vim. If you don't have a GUI, use the nano editor (or for root access, sudo nano).


Installing a PHP package generates two packages. One with version number and one without

It's for your convenience :)
The package php-mysql is called a "dependency package". It will depend on Ubuntu's default PHP version (currently 7.2). Whenever Ubuntu decides that 7.3 is stable enough, the dependency packages will change dependencies, and everyone will get the 7.3 version installed.
(Text partially taken from the output of apt-cache show php-mysql.)


try to format a partition with Windows 7, if you don't need them, and create / partition on this space. And try to create SWAP partition, /home partition behind


HP, like any other OEM, sources their peripherals through a wide variety of vendor sources. Just because it has the HP tag on it doesn't mean HP made it. If you are looking for Linux driver support for the extra multimedia keys, Google search on the model #, part # and "Ubuntu". There's a very slim chance that HP might have a Linux driver for it, but I wouldn't hold out much hope on that avenue.


"Try Ubuntu without installing" appears on one computer, not on another

The best way to know why it is behaving like this is to go thru the source code of Ubuntu 12.04.05. Ubuntu is open source and you can go thru it. Essentially the kernel modules which are interacting with H/W and to some extend of the installer routines. Any time installers are running they probe the underlying hardware and based on that they behave. Your old computer may be having USB 2.0 interface only plus a lot of stuff(in terms of old hardware) which makes the installer make a decision how to behave. Please specify full details of all the H/W configuration and the screen shots to logically find out why it is doing something like that.


No Application found in Ubuntu Software Center 20.04

It boils down to an issue between the apt and snap versions of Ubuntu Software.
This answer from an earlier question helped  to provide a solution.
What I did
In terminal:
snap remove snap-store
sudo apt-get install gnome-software

followed by
sudo apt install gnome-software-plugin-snap

That installed Software  as opposed to the large yellow icon previously associated with Ubuntu Software after which the "missing" packages were then correctly listed.
There are solutions to restore the old icon if I wish (not essential) and to reinstall snap-store which can apparently co-exist with the apt version


Install the package firmware-b43-installer:

sudo apt-get install firmware-b43-installer

You will need to enable the multiverse repository to be able to do this. If you chose to install 3rd party software when installing Ubuntu, then it should already be enabled. If not, see this question.

You may need to restart your computer afterwards for the card to start working.


Ubuntu Landscape - Server certificate verification failed

Unable to test currently, but the Quick Start Guide suggests to add the certificate file to /etc/landscape/client.conf with this line:

ssl_public_key = /etc/landscape/server.pem


Samsung phone not recognized in Ubuntu 12.10 using USB cable

That is a current problem that I don't see Samsung fixing unless they make a version of Kies for linux. Depending on what you are trying to do you can click the usb symbol and it should take you to an option screen. Choose Camera mode rather than MTP. This will let you access the memory in a limited fashion. I think there is a file size limit for when you try to transfer files. Another option is to get a microSD and plug that in your computer before putting it in your phone (Get one with the usb or SD attachment). Anything else really depends on what you are trying to do. It sucks, I know.


SOLVED: The wired interface (eth0 in my case) must be shut down otherwise it appears to disrupt the correct operation of the wireless interface (eth1 in my case) and wpa_supplicant.


I think you should look around here. You can find there the API, examples and the cookbook.


Can I add to the Super key/Applications search sources?

First, Gnome Shell, and certainly in Gnome 19.04, should correctly find file names in your home folder. Make sure that, in "Settings" - "Search", "Files" is turned on. It will, by default, only search your Home folder. Clicking the cog wheel below allows you to add other search places. Avoid indexing too much of files, because there is a performance cost.

In Gnome shell, additional search sources can be added as "Search Providers". Several search providers come with Gnome Shell. You can toggle them on or of in "Settings" - "Search". Third party search providers are typically installed through a Gnome Shell extension. For example, a YouTube Search Provider extension can be installed from the Gnome Shell Extensions website. To add your own search provider would require some technical programming skills for coding a custom extension.

Alternatively, you could consider a keyboard launcher such as Albert or Ulauncher. These provide a range of plugins to extend their capability beyond that of quickly launching an application. None of these launchers is included in the standard Ubuntu repositories, but they can be conveniently installed using either .deb files or a repository.

With some bash knowledge, you can go a long way with menu systems such as "dmenu" or "rofi". These are desktop independent menu systems running on plain X. You can feed them the output of any script, in any programming language, and they will present the choices in a very efficient menu, where typing some parts narrows the choices very quickly down to the item you want. These powerful tools are commonly used in lightweight windowmanager-only setups (openbox, tiling window managers such as i3).

See here on how to map another command to the Super key.


This seems to be an issue with PhpStorm and IntelliJ platform in general.

In order to fix it, as per comments in their issue tracker, you need to add this to idea.properties file: suppress.focus.stealing=false and restart PhpStorm.

I had the same problem on Debian with XFCE and this solved it for me.


Install a package which is not in a repository

Download TeamViewer and save the .deb file.
Open the folder where you saved the file.

Click on the downloaded .deb file.
Ubuntu Software Center opens.
Now click on Install to start ...

All dependencies including the i386 (32 bit) packages needed will be installed automatically.
This is the recommended way ... as you can read in the TeamViewer installation instructions.
TeamViewer isn't available in any repository, to update it you have to repeat the procedure.


I had a similar problem with Ubuntu 14.04. When I tried to install openssh-server (and any other software) I got the E: Error, pkgProblemResolver message while none of the packages were "hold".

The problem is caused by the versions of packages you try to install. The solution may involve removing and downgrading some of the packages you already have. You may use aptitude to get suggestions on how to solve the problem.

First, you must install aptitude if you do not have it

$ sudo apt-get install aptitude

Then, you can run the command indicating that you want to install the openssh-server

$ sudo aptitude install openssh-server

The program will show you suggestions about how to solve the problem. Usually the first solution does not work. You can press n to request a new suggestion. Press y to accept a solution that installs the openssh-server and downgrades some other packages.


Docker fails to start if configured to use devicemapper with direct-lvm

The status messages indicated that my thinpool was not available. lvdisplay said the same:

#$ sudo lvdisplay ubuntu-vg/thinpool
  --- Logical volume ---
  LV Name                thinpool
  VG Name                ubuntu-vg
  LV UUID                Or2cLx-ENFq-sZqh-kxUw-0FEQ-rEzi-vXCi3C
  LV Write Access        read/write
  LV Creation host, time docker-lvm, 2016-07-12 15:57:06 +0200
  LV Pool metadata       thinpool_tmeta
  LV Pool data           thinpool_tdata
  LV Status              NOT available
  LV Size                14,07 GiB
  Current LE             3601
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto

Note:
  LV Status              NOT available

Trying to activate it said:

#$ sudo lvchange -ay ubuntu-vg/thinpool
  /usr/sbin/thin_check: execvp failed: No such file or directory
  Check of pool ubuntu-vg/thinpool failed (status:2). Manual repair required!

The tools for thinpools are configured in /etc/lvm/lvm.conf and there i found the following paragraph:

    # Configuration option global/thin_check_executable.
    # The full path to the thin_check command.
    # LVM uses this command to check that a thin metadata device is in a
    # usable state. When a thin pool is activated and after it is
    # deactivated, this command is run. Activation will only proceed if
    # the command has an exit status of 0. Set to "" to skip this check.
    # (Not recommended.) Also see thin_check_options.
    # (See package device-mapper-persistent-data or thin-provisioning-tools)
    # This configuration option has an automatic default value.
    # thin_check_executable = "/usr/sbin/thin_check"

I looked up the packages mentioned there and i found that the package thin-provisioning-tools is available but not installed.

#$ sudo apt-cache policy thin-provisioning-tools
thin-provisioning-tools:
  Installed: (none)
  Candidate: 0.5.6-1ubuntu1
  Version table:
     0.5.6-1ubuntu1 500
        500 http://de.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages

After installation the package the utils for thinpools were available. Manual Activation of the docker-thinpool succeeded and also on system startup the volume was activated and docker starts successfully.


You can use this setup protocol and repeated here. It works pretty well. I can connect via RealVNC and MAC screen share. The last one doesn't work that well though.


Why `apropos url` output 'url (7)' but I can't use the command url

When apropos url will return something like url(1) then you can to use url as a command-line. Until then, url(7) will refer at a macro  package or a convention (miscellaneous).

  The number corresponds to what section of the manual that page is
  from; 1 is user commands, while 8 is sysadmin stuff. The man page for
  man itself (man man) explains it and lists the standard ones:

MANUAL SECTIONS
The standard sections of the manual include:

1      User Commands
2      System Calls
3      C Library Functions
4      Devices and Special Files
5      File Formats and Conventions
6      Games et. Al.
7      Miscellanea
8      System Administration tools and Deamons

Distributions customize the manual section to their specifics,
which often include additional sections.

Source: https://unix.stackexchange.com/questions/3586/what-do-the-numbers-in-a-man-page-mean.


Mouse cursor disappears in Kubuntu 15.04

I had the same problem before in ubuntu. Try this command:
gsettings set org.gnome.settings-daemon.plugins.cursor active false

and reboot your computer.


Using iptables is an exellent choice it's a very powerfull firewall feature built in to the Kernel

as root or with sudo:

iptables -A INPUT -s 192.168.1.100 -p icmp -j DROP

will block all ping(icmp requests) from a  the specified IP.

The following to block all ICMP:

iptables -A INPUT -p icmp -j DROP

Basically omitting the ip will bock ALL ping requests.

to remove the following active firewall rule:

iptables -A INPUT -p icmp -j DROP

change the -A (append) to -D (delete)

iptables -D INPUT -p icmp -j DROP

But do you have a good reason to block ICMP?
Usually ICMP is a good thing. It is used for MTU discovery etc. Basically making sure
that you will have a optimized network/Internet experience.

More info on why you shouldnt block ICMP here


Ubuntu 19.04 - WLAN switches off although displayed as on in status bar

Not a solution but a workaround (in my case). Point ping at your gateway while connection is up

ping 192.168.x.x

I have a similar (except for 'airplane mode') problem on Ubuntu 16.04 LTS, using a Intel PRO/Wireless 4965 [Kedron] (rev 61)
I can connect to my router (TP-Link) with no problem but after a while, randomly the connection drops. It seems like the NM applet does not 'notice' the connection is down.
When this occurs and I set out a ping to my gateway, it does not reply.
However, if I reconnect and set a ping to my gateway while the connection is 'alive' no connection drops occur.

I've more than one router available. But behaviour is the same on 2 of them. ( I did not yet tried the others.)

So I wonder if your connection is down can you:

-Ping your gateway?-

-using a 'cable' and all s'well?-

-Other computers/clients connecting to same router have NO issues?-

If connection is down, what is the output when you run (without the '~$') :

~$ nmcli general status

~$ nmcli -f ssid,freq,chan,signal dev wifi list

~$ ip -c monitor

I've been lookin for a solution for several weeks I noticed that some users were helped by just running:

-sudo apt update-

-sudo apt dist-upgrade-

Other things to consider (on your router):

-Change the radio-channel from auto to manual-

-Change bandwidth from auto to manual-

-Change 802.11 standard   (try A,B,G only or whatever is there for you).

How to choose a radio channel.

-Use radiobutton 'Disconnect' in NetworkManager Applet (do not disable Wifi)-

-Run -nmcli -f ssid,freq,chan,signal dev wifi list- again.-

-Pick a channel You DONT see listed, one far away from you or one not occupied a lot.-


How to emit onDropped in QML drag n drop example?

Apparently a drop needs to be generated explicitly by calling the drop() method on the Drag object

Try adding this line inside of the MouseArea, just above drag.target: parent

onReleased: parent.Drag.drop()


How can I fix my files' "modified dates"?

Changing the time back to the current date and time is fairly easy. From the manpage:

touch {filename}

You can use wildcards. Also with ...

-d, --date=STRING
          parse STRING and use it instead of current time

you can use a custom date and with

-t STAMP
          use [[CC]YY]MMDDhhmm[.ss] instead of current time

you can use a custom time in case you want specific timestamps set for those files.

As to why it happend that is going to be guesswork. Some examples:

files could come from another machine that has a wrong date.
files could have been restored from a backup or tar file.
your time was set wrongly.


copy/paste with mouse doesn't work anymore

Try to install gpointing-device-settings

sudo apt-get install gpointing-device-settings

You then check the  'use wheel emulation'.


USB Device error: "unable to enumerate device"

Heads up - for me, this was caused by having my USB drive plugged into a USB3 port on an ESXi server. The device was passed through into the virtual machine connected to a virtual USB2 controller. That was the problem. Deleting the device and controller and re-configuring as USB3 resolved.


How to use fingerprint authentication on a HP DV6-3049TX?

There's a similar question asked here:

How can I use my fingerprint reader?

This comment: FPrint -  points out a software that could help you, it has a list of supported devices, but aparently your laptop is not in the list. Nonetheless I would give it a try


scheduler: how to tune cfq to favor interactive processes

Just a partial answer, done more research and experiments since asking which have solved my problem, and seeing there are no responses

There are known issues/bugs in the Linux kernel schedulers as of early 2016.

The short summary is that under different circumstances, cores remain idle even though there are runnable processes in the process queue.

References:

The Linux Scheduler, a decade of wasted cores
github repository with experimental fixes to scheduling

A switch from btrfs to ext4 can alleviate these issues:

I personally switched back from btrfs to ext4. I/O performance has noticeably improved.

A switch to SSD can further alleviate IO performance

SSDs have dropped significantly in price and reliability. A 2TB Samsung SSD (EVO 850) now costs a little over $600.  Switching the system (root and home) to SSD now makes the intensive backup activity completely unnoticeable (system SSD is snappy while doing heavy writing to a regular ext4-formatted disk on the same system).

Finally: with SSD, the benefit of complex schedulers in the kernel seems to becoming questionable.  I changed my default to noop with no noticeable degradation whatsoever in performance. I fact, with a noop scheduler, I see a reduction in system load, lower CPU scaling numbers, and lower hardware temperatures.

$ cat /sys/block/sda/queue/scheduler
[noop] deadline cfq

$ cat /proc/cpuinfo | grep  Hz
model name      : Intel(R) Core(TM) i7-4771 CPU @ 3.50GHz
cpu MHz         : 836.308
model name      : Intel(R) Core(TM) i7-4771 CPU @ 3.50GHz
cpu MHz         : 990.253
... similar low actual frequency scaling for all cores ...


AWK - How to extract matches including part of filename from multiple files

If you have GNU Awk:

$ gawk '
  BEGINFILE{
    split(FILENAME,a,/=/)
  }
  match($0,/"number":[0-9]+/){
    printf "%s:%d\n", a[2], substr($0,9+RSTART,RLENGTH)
  }
  ' total_val*
5555:1234

Or with Perl

$ perl -lnE '$x = (split /=/,$ARGV)[1]; say "$x:$1" if /"number":(\d+)/' total_val*
5555:1234

In neither case is any checking done (for example, that the filename splits successfully on an = sign).


As it has been solved in the comments, the solution is to set the command to the command within a shell and delayed, like so:

bash -c 'sleep 10 && xset m 2 12'

The delays allows for GUI to properly start up, and then runs the specified command.


PostGIS dependency conflicts (ubuntu 14)

The problem, as @saircot895 lead me to discover, was a conflict between the repos. The specifics were not visible in the questions I asked, because I had not delved deeply enough into the Fabric script which was setting up the virtual Ubuntu box in question. In the event, the script was using the older "Precise" release for postgres itself, but postgis was looking on the newer "Trusty". Changing the postgres install (and the rest of the provisioning) to the newer release resolved the issue.


One monitor getting spilled over into other monitor: how to do a 100% reset of gnome graphics configuration

lkjoel has written this blog post:

Press
 CTRL+ALT+F3

Log in

Type:

sudo rm -f /etc/X11/xorg.conf
sudo rm -f xorg.conf*
sudo service lightdm stop
sudo service gdm stop
sudo service kdm stop
sudo service lxdm stop
sudo service xdm stop
sudo service wdm stop
sudo Xorg -configure
[ -f xorg.conf* ] && sudo mv xorg.conf* /etc/X11/xorg.conf
sudo dpkg-reconfigure $(dpkg -l | awk '{print $2}' | grep "^xserver" | tr '\n' ' ')
sudo update-initramfs -u

Reboot

may be it help


what can be done juju for wordpress users? How To Work with it?

From Ubuntu Juju | Deploy page:

  Juju manages your systems architecture as services in the cloud. It is a simple client/server application that bootstraps an instance to create and control the rest of your environment. You can use it through a GUI or from the command-line, scale in all directions and easily move your environment between clouds.

It's not related directly to shopping or Wordpress, but you can use it to deploy a wordpress blog (check the tutorial below).

juju deploy wordpress is a command-line interface (CLI) command which instructs Juju to deploy a new instance (VM) in the cloud, using the settings defined in your Juju "environment". The equivalent operation in Juju GUI can be by dragging and dropping a charm, directly from your browser.

For more info check:

Juju Documentation, including a "Getting Started" tutorial.
Juju Features
Juju GUI Demo
Install Juju

You can find a lot of answered questions here about Juju.
The source, bugs and other info can be found on Launchpad.


How to prevent Ubuntu/XUbuntu from automounting repositories from Ubuntu CDs?

I think (97% sure) you are referring to this message box.

To disable it, open a terminal and run the command below. (Then log out and log in again, to see that this annoying message box no longer appears.)

gsettings set com.ubuntu.update-notifier auto-launch false

Ubuntu (though not Xubuntu) also provides a neat graphical graphical way to do this:

Go to System Settings --> Details --> Removable Media --> Software and select Do nothing.


Is there a way to open 4 terminal windows every time I login?

You could add this to your startup applications. Press the Ubuntu button(top-left), type and click Startup Applications, there, click on Add and type whatever you want in the title and put this is in the command section:
gnome-terminal --window-with-profile=default && gnome-terminal --window-with-profile=default && gnome-terminal --window-with-profile=Mail && gnome-terminal --window-with-profile=Mail

As for your automatic SSH logging in needs please take a look at this question here - Can I create a SSH script and How can I setup password-less SSH


How can I give more space to a preexistent Ubuntu partition?

Note: This procedure assumes that /dev/sda4 still contains the original bootable Ubuntu installation.
Note: /dev/sda3, Windows partition, needs proper shutdown, and possibly chkdsk repair.
Make sure that you have a good backup of your important Ubuntu files, as this procedure can corrupt or lose data.
Keep these things in mind:

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

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

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

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

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

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

boot to a Ubuntu Live DVD/USB, in “Try Ubuntu” mode
start gparted
delete /dev/sda8 partition
move /dev/sda4 partition all the way left
resize the right side of /dev/sda4 all the way right
click the Apply icon


Converting images of different types to PDF

You could create a bash script:

#!/bin/bash

for f in *.jpg; do
  convert ./"$f" ./"${f%.jpg}.pdf"
done

EDIT:  Source - https://unix.stackexchange.com/questions/29869/converting-multiple-image-files-from-jpeg-to-pdf-format


Need to repeat pairing to connect bluetooth headphones on Ubuntu 18.04

I use Blueman sudo apt install blueman  Once I turn on my headset, I right click on the headset in Blueman and check audio profile, set it to off, then disconnect, connect and then set audio profile to A2DP in Blueman.

It isn't the best fix as there is likely a bug somewhere in bluez or pulseaudio


HP Laptop Installation problem: "The system is running in low-graphics mode"

I also have a HP laptop and this helped me to solve my problem!

How to fix "The system is running in low-graphics mode" error?


What is the package name of the lock screen?

The package providing the lock screen is gnome-screensaver.

Read more about it here:

https://wiki.ubuntu.com/DebuggingScreenLocking/HowScreenLockingWorks


Lubuntu wireless not works at Acer Aspire 1410

Connect your notebook directly(ethernet), and use that connection to update your drivers, following the instructions in the linked forum page:
Broadcom wifi issue on 14.04 Lubuntu

Amended:
in response to a comment by @chili555, this link documents possible alternatives.
Excerpt from source:
Ndiswrapper is a Linux module which allows Ubuntu to use the Windows driver for wireless cards. One may want to use ndiswrapper for a number of reasons:
1) No open source driver provided in the Ubuntu repositories.
2) The driver provided by default in Ubuntu is not working out.
3) The proprietary driver provided by the card vendor is not working out.
4) Test ndiswrapper performance versus alternative driver(s).
5) Test hardware failure for your card.

The instructions listed through the link are clear and concise, and should be able to point you in the right direction.


Language changes constantly in application input

Firstly try this command:

sudo dpkg-reconfigure keyboard-configuration

If it doesn't work permanently, try this solution.


When you type sudo apt-get install packageName, apt looks for package 'packageName' in the repositories listed in the configuration file /etc/apt/sources.list.

Error E: Unable to locate package xxx indicates that the package cannot be found among the package lists retrieved from all the repositories listed in sources.list.
Causes for this can be:

The package does not exist at all (for example a typo in the name).
The package exists in a repository that is not listed in your sources.list
The package exists in a repository that is listed in sources.list, but you have not retrieved the lists of packages contained in that repository to your machine yet.

In your case:
(1) is excluded as I can find both packages 'b43-fwcutter' and 'linux-firmware-nonfree' from my own machine.
(3) is easy to check: just run sudo apt-get update before the apt-get install command and see if it works now.
(2) is however the cause I would bet on. Maybe you removed the repositories in the 'Software and Updates' UI? If so, please try to reselect everything in the 'Ubuntu Software' tab there and retry here above update+install procedure. Alternatively, refer to the accepted answer to the AskUbuntu topic 'How do I restore the default repositories?' to restore the default apt configuration.


Some applications lag in Ubuntu 18.04 installed on AMD Ryzen Threadripper 1950x

The problem magically disappeared. I have a dual display system. One is connected to the graphic card by a dp to mini-dp cable and the other one by an HDMI cable. The only two things that have changed are 1) I've changed the HDMI cable and 2) I changed the primary display to be monitor 1 rather than 2. I don't think these should have anything to do with my problem, but these are the only things I could think of that have changed.


Is it possible to remove the dash window control buttons?

There is no current way to change the order of those buttons nor is there a plan to add that option.


How to make Firefox trust my companies certificate on my machine?

Firefox has it's own certificate store and does not use the system-wide certificates in /usr/share/ca-certificates, so the first answer you linked has no impact on Firefox. (It is also clearly said in the comments to the answer that you linked)
The second article from Mozilla seems too complicated for me.
It should work the following way (at least it works for me):
In Firefox, go to Preferences -> Privacy & Security -> Certificates -> View Certificates -> Import. Select the file with your certificate. Firefox should ask you under which category it should store the certificate, select "Authorities". Or it will maybe recognize by itself that it's a CA certfifcate and put it under the appropriate category. After you finish the import process, you can check if your imported certificate is visible in the "Authorities" section.
There are also more answers regarding Firefox here: Add certificate authorities system-wide on Firefox