Failed to acquire the VirtualBox COM object on Ubuntu 14.04 LTS

I encountered this situation after a power loss and reboot of my host system.

Overview

VirtualBox stores its global configuration in ~/.config/VirtualBox/VirtualBox.xml, (if you've upgraded from early versions it may be in ~/.VirtualBox/VirtualBox.xml).  The file includes global configuration options and the list of registered virtual machines with pointers to their XML settings files (for each machine under ~/VirtualBox VMs).

Options

To solve a corrupted VirtualBox.xml do one of the following, in order of preference:

Restore a backup. Ubuntu comes with Backups (Déjà Dup) installed by default. If you're using it, you can easily restore the file by navigating to ~/.config/VirtualBox/, right-clicking on VirtualBox.xml, and choose Revert to previous version...   more details
Restore a copy. Each time VirtualBox Manager starts up, it creates a backup copy of ~/.config/VirtualBox/VirtualBox.xml (called ~/.config/VirtualBox/VirtualBox.xml-prev). The drawback is this file will/may only be useful if you haven't started VirtualBox Manager.

Steps to restore a copy

Ensure VirtualBox Manager is not running.
Navigate to ~/.config/VirtualBox/
Rename ~/.config/VirtualBox/VirtualBox.xml to something like ~/.config/VirtualBox/VirtualBox.xml-original
Rename the backup ~/.config/VirtualBox/VirtualBox.xml-prev to ~/.config/VirtualBox/VirtualBox.xml
Start VirtualBox Manager. This is a copy of the state of the last VirtualBox Manager startup, and hopefully resolves your situation.

Remove the file. Always Backup first, including VirtualBox VMs.   This is a last resort.

Steps to remove the file

Backup
Navigate to ~/.config/VirtualBox/
Delete/rename the VirtualBox.xml file.
Start  VirtualBox Manager.  This will recreate a file during startup.
The result of removing the file will likely be a loss of some/all of your machines in the list. Any missing machines might be able to be restored by re-registering .vbox files and {snapshot}.vdi files stored by default in the ~/VirtualBox VMs folder.  Full details of how to recover this condition are beyond the scope of this question.  Always

Notes:

The tilde (~) is a shortcut representation for the $HOME environment variable. It can be cut-and-paste into a GUI program like Gnome Files (Nautilus) (which supports freedesktop.org conventions), or in a terminal.

To past a path in the location bar of Gnome Files (Nautilus), press CTRL-L. Then type or paste a path.

Before upgrading: It is prudent to shutdown each virtual machine (in lieu of a suspended\snapshot state).
Before upgrading: It is also important to eject/unmount any VBoxGuestAdditions.iso in CD drive. Then, new version can be inserted and installed after upgrade.


mount readable for everyone using udisks-glue

If /dev/sdb1 is ntfs filesystem, you should make sure ntfs-3g has been installed.
Then just

sudo ntfs-3g /dev/sdb1 ./yourdir

and it can be read/write by all users.


It's normal to see 1 GB usage for 30 WordPress sites without a caching layer. For sites with a caching layer and with most visitors are not logged-in, it is not normal.

In most cases, it is not Nginx, but php-fpm and MySQL that use more memory than Nginx. Of course, Nginx is more efficient than Apache. While top is useful, you may use this scirpt to find which process uses how much memory. Please know that *ps_mem.py* requires 'root' or 'sudo' privilege.

If you'd like to reduce the memory usage, you may use a caching layer, such as Varnish. Alternatively, you may use application level caching, such as WP Super Cache or Batcache (both work fine with APC as WP Object Cache). I hope that helps.


Finding a large file being created by the system

With the following command you can find the recently modified/created file on the system disregarding the file size:

find ${1} -type f -size +1G| xargs stat --format '%Y :%y %n' 2>/dev/null | sort -nr | cut -d: -f2-


Forgot the password type in the Ubuntu Linux for Windows during set up of bash Ubuntu

In Windows' Microsoft Store, uninstall Ubuntu then uninstall Windows Subsystem for Linux.

Reboot.

Go back into the Microsoft Store.

Reinstall Windows Subsystem for Linux.

Reinstall Ubuntu


Best way to upgrade kernel in Ubuntu Desktop 14.04.3 LTS

Installing from Ubuntu repositories is preferred.

This will install a supported Ubuntu kernel and it will get updates.

If you install a mainline kernel, you may have issues with some drivers, and you will have to update it manually.

Ubuntu kernel 4.2 will be default in the next "point" LTS release 14.04.4 that is scheduled to be out in Feb 2016.

There should be no problems in upgrading to 16.04.

Installing linux-generic-lts-wily now you install that kernel a bit earlier than it will be released for all LTS new installs.

You can read more about HWE Stack.


Bluetooth not working on BCM43142 on 14.10

I had the same issue. I read some answers and this is the gist of it:

Find ID of your device:

  $ lsusb | grep Bluetooth

My output for example:

Bus 001 Device 003: ID 0a5c:21d7 Broadcom Corp. BCM43142 Bluetooth 4.0

from which 0a5c:21d7 should be remembered.

Get a hex file for your device:
After searching for bluetooth drivers in Google I have chosen this download:
http://drivers.softpedia.com/get/BLUETOOTH/Broadcom/Broadcom-43142-Bluetooth-40-Adapter-Driver-12007030-for-Windows-8.shtml#download
How to get the right hex file.

So I have the id of the chip: 0a5c:21d7 and a bunch of the hex files from the downloaded archive. How can I get the right one for me? The trick is to investigate the .inf file that instructs windows what to install. Searching for 21D7 (note the capital D instead of 'd') I get this:

%Dell1704.DeviceDesc%=RAMUSB21D7, USB\VID_0A5C&PID_21D7 ; BRCM Generic 43142A0 RAMUSB

The USB/VID&PID is what I get on lsusb: capital(0a5c:21d7). The RAMUSB21D7 is what I need to search next in the inf file (it is the device's description).

And this is my result:

;;;;;;;;;;;;;RAMUSB21D7;;;;;;;;;;;;;;;;;

[RAMUSB21D7.CopyList]
bcbtums.sys
btwampfl.sys
BCM43142A0_001.001.011.0122.0126.hex

And the hex file I shall use is BCM43142A0_001.001.011.0122.0126.hex Extract this into home directory.

Type this:

  dmesg | grep Bluetooth

Result according to your issue is:

  [ 4967.683179] Bluetooth: hci0: BCM: patch
  brcm/BCM43142A0-0a5c-21d7.hcd not found

It will tell the name and file its looking for. I your case it is:brcm/BCM43142A0-0a5c-21d7.hcd

Convert the correct hex to hcd file.
Open terminal and type these commands:

  sudo apt-get install git

  git clone git://github.com/jessesung/hex2hcd.git

  cd hex2hcd

  make

  ./hex2hcd ../BCMxxxx.xxx.xxx.xx.hex BCM43142A0-0a5c-21d7.hcd (Correct
       hex file and required hcd name here)

  sudo cp BCM43142A0-0a5c-21d7.hcd /lib/firmware/brcm


Finally found and installed 14.04 LTS, sound has been restored in other (default) Ubuntu version (not Lubuntu)


You can see from the above image that gimp and babl packages failed to build.

You should contact the author of the PPA to see if he can resolve this problem.


Add text but first check if it's present already prevent duplication

The simplest way that comes to mind is to first issue a grep call for the text to be added on the file itself and then use the || ( OR ) operator and after that issue the echo ' ' >> call like so:
grep '            routes:' /etc/netplan/50-cloud-init.yaml || echo '            routes:' >> /etc/netplan/50-cloud-init.yaml

The text will be added only if it is not already present in the file.
The command after || will only be executed if the command before it fails.
This means if
grep '            routes:' /etc/netplan/50-cloud-init.yaml

fails to return a result which means the text is not in the file,
then
echo '            routes:' >> /etc/netplan/50-cloud-init.yaml

Will be executed and the text will be added.
Otherwise if the text is already in the file nothing will be added to it.
This has to be used for each line of text you wish to check for before adding it.


How to make program autostart only in GNOME

You can edit the startup object in ~/.config/autostart and add this to the end:

OnlyShowIn=GNOME

It's a poorly named option, but it will cause KDE not to start the application.


Install pandas to python3.5 instead of 2.7

For Python 3.4.2 Shell, the advice from Timo made the difference:

In the Terminal type

sudo apt-get install python3-pandas

Then in the python shell type

import pandas

and no errors!


Per your request on the other question, here is my answer again:

  I'm sure there is a cleaner way of doing it, but for your second question you can try this:

   xprop _NET_WM_PID | sed 's/_NET_WM_PID(CARDINAL) = //' | ps `cat`

  This will make your cursor a cross with which you can click on an open window. It will report the PID and command in the terminal you ran it in.

  In general, xprop and xwininfo will provide you with a lot of information about an open window.

The "apostrophes" I used for surrounding cat are the ~ key on my keyboard without pressing shift. This should give you some more info on the subject:

Grave Accents and the backquote


How do you clean up a text background with Gimp?

I know how to do it in Photopea (I made Photopea), but it is probably the same in all programs.

Choose Magic Wand (Fuzzy selection) and click on the area that you want to remove (try different values of Tolerance). Now you can fill the selection with the white color (Edit - Fill, or paint with a large brush).

Another way is using Levels (Ctrl + L or Image - Adjustments - Levels). Drag the right-side limit (for whites) to the left to make almost-white colors completely white. I just tried it on your image:


Here is a solution for ISE 13.4. I have just changed 'Exec' parameter of the desktop file.

  Exec='/home/user/Xilinx/13.4/ISE_DS/ISE/bin/lin64/ise'

To be able to run ISE, we should set environment variables first running source settings(32/64).sh in the ISE_DS folder.

It seems to works fine.


Is this an error => Starting pkgProblemResolver with broken count: 0

I'm using KDE neon 5.11 I learned a couple of things that those messages aren't errors and that with the following command everything updates the ubuntu and KDE packages

sudo apt-get update && sudo apt-get dist-upgrade && pkcon refresh && pkcon update


You just have to give

:command Q q

Similarly, you can do for other commands like,

:command WQ wq
:command W w


There is nothing spinning in a SSD so there is nothing to spin down. Modern SSDs use only a fraction of a watt so there would be no power consumption savings. The drive must be awake enough to know when to receive commands so the power can't be totally shut down. Maximum power consumption, still a fraction of a watt with the latest drives, is during writes; much less during reads.

This answer is OS independent and applies to Linux, OSX, Windows, whatever. Modern OS releases, since Windows Vista for example while less so for Linux, understand that they are working with a SSD and don't defrag the drive.

Do make sure you are backing up your data because as SSD speeds have increased, their lifespan has decreased (number of times a given bit can be rewritten). If you never use more than 20% of your drive, it might last 50 years. If you fill it to 90%, it could start failing within a year.

Unlike a hard drive, they rarely fail dramatically. The drive can detect when some bits are "wearing out" and switch to some backup areas. Eventually you'll notice the maximum size of the drive decreasing as worn out areas are made unavailable. In large data centers, SSDs are used for their speed and not reliability, they have about the same failure rate as data center quality hard drives.

That said, I have 3 SSDs in my HP Z420 Workstation and really enjoy the performance improvement while saving energy. Have been considering replacing the power supply with a smaller, more energy efficient one except the 6-core Xeon processor does use a fair amount of energy.


arrow key problem with vnc server in Ubuntu 18.04

This is a workable xstartup file:

!/bin/bash

export XKB_DEFAULT_RULES=base

export SESSION_MANAGER=

export DBUS_SESSION_BUS_ADDRESS=

startxfce4 &

Here, "export XKB_DEFAULT_RULES=base" solves the arrow key problem.


Plex Media Manager won't find /media/Movies or /media/TV internal HDD

I had that at first, it was erratic.

Then I found that you have to follow their naming conventions (ish)

Plex Media Naming Guide

Mostly it's this:

Movies\
    MovieName (YEAR).extention
    MovieName (YEAR).extention

TV Shows\
    ShowName\
       Season 1\
          ShowName S01EXX.extention

Usually then it's easier to just delete the section out of Plex and re-add it.
If you want to force it to re-do just one show, go to the show in plexweb and click the Unmatch link then re-scan, that seems to (eventually) sort itself out.


That means that this touchpad is not supported yet by Linux.

You can't use Windows driver.

You can report it to Launchpad by running in terminal

ubuntu-bug linux

If you want to get it working sometime be prepared to give feedback.


How to change the shortcut to move windows from Alt to Super/Meta?

Install compizconfig-settings-manager.

Open CompizConfig Settings Manager and navigate to the Resize Window plugin.

Click the <Super>Button2 button and rebind the shortcut.


How does the command for installing RVM work?

It turns a string into the file descriptor for the output of the bash script that it represents. This might be confusing, here's an example

if you type echo <(ls) it will open a new file descriptor, the name of which is substituted. So the command might turn into say echo /dev/fd/63.

A program that expects a file can now read the output of the command without having to accept stdin.

$ my_program ls
Error: 'ls': No such file or directory.
$ my_program <(ls)
my_program was called with the argument /dev/fd/63
bin dev etc ...

Many Linux program will, if not provided with a source of input, wait for standard input. Because standard output can be piped to standard input with the "| " operator, you can then use say ls | grep hello. This only works because grep would've waited for input anway, if it'd expected a file name to open and read to get its data, the pipe operator doesn't work. This is why you need <(...).

I hope this is intelligible. :-)

Together with the < operator to redirect the output of a file to a programs reading of stdin, this makes for the following meaning:

Bash: read the output from this file, which is created from the output of this command.

Clarifications:

standard input: a "file" (not really, but in linux everything acts like a file) that, when read, magically contains what you've typed
standard output: a "file" that, when written to, will be printed to the virtual terminal
operator (i.e. < or <()): Same as in regular maths, expressions of operators and operands will be evaluated and substituted. 3+2*3 turns into 5*3 turns into 15. It's the same in the bash language.

A nice example to emphasize Roger's point is this expression:

if [ -f my_condition ] then something fi

Here the contents of the brackets will be evaluated as a conditional statement, i.e. if my_condition is true, then do something. But: [ is actually just an alias of the program test, which, when called with the parameter -f, will check if a file exists.


I have an X61 (not tablet) w/10.04 that I use with Thinkpad docking station. It required no additional configuration. I use the DVD all the time. I'm reasonably sure your setup will be the same.


I am not entirely sure I believe that game is really supported directly under Linux at all.  Short of seeing something on the actual BOX ITSELF saying so, I would tend to assume this is probably miscategorized on Amazon.

I did some searching and was unable to find any website talking about a native Linux port of the game, only people talking about (successfully) getting it running under Wine.  So, probably a miscategorization.  You could ask Amazon support about this if you're really feeling hopeful, and maybe see if you could get somebody there to either actually read the box or guarantee a refund should you get it and find out that it's simply been miscategorized.  That's the best advice I've got for you.

Btw: check out http://humblebundle.com/ for a fair number of pretty cool indie games that are directly supported on Linux and easy to install - most of them can even install directly from the Software Center, once you've purchased your Bundle!


Does choosing the "Replace Windows 7 with Ubuntu" delete my drive data?

It will delete everything.

When I say everything, I mean the whole drive. I don't have any documentation to show you right know, but I have experience on this. Recently I suggested this option to somebody and the whole drive reformatted. C:\ , D:\ .. everything.


Write a script to connect to WPA2 network if you know name/password

You can create a script to write AP config to /etc/wpa_supplicant.conf and starting up wpa_supplicant with the created configuration file manually. Please refer to the following example:

wlan_interface="wlan0" # Modify as needed
connect_wpa2_ap() {
    echo Connecting to WPA2 AP with SSID $1
    # config_wpa_supplicant $1 $2
    echo -e "\
ctrl_interface=/tmp/ctrl-$wlan_interface.pid
eapol_version=1
ap_scan=1
p2p_disabled=1
network={
ssid=\"$1\"
 scan_ssid=1
 proto=RSN
 key_mgmt=WPA-PSK
 pairwise=CCMP TKIP
 group=CCMP TKIP
 psk=\"$2\"
}
" >/etc/wpa_supplicant.conf
    /sbin/wpa_supplicant -i "$wlan_interface" -B -c/etc/wpa_supplicant.conf
}

Connect with connect_wpa2_ap <ssid> <password>.


On 17.04 , gnome programs refused to be erased and instead erased my program removal icon

Though your terminology is very different than we use here, I'm assuming that by 1) erasing program you meant uninstalling or removing programming, by 2) get/remove program icon Gnome software which is used to install or remove applications and by 3) gnome programs and gnome user interface program you mean the gnome-shell and its session.

I also assume you can still log in to the Unity session. So, log in to the Unity session (marked as Ubuntu (Default) in login screen) and use Ctrl-Alt-T keycombo to bring up a terminal.

Now type this command into the terminal and hit Enter key. When asked, type your sudo password there.

sudo apt-get install gnome-software

Once it's completed use this command to completely remove gnome-shell.

sudo apt-get autoremove gnome-shell gnome-session


A better way to install the Sun JDK is like so:

How do I install Java?

Use update-alternatives to do all the heavy lifting for you.

In any case, updating the PATH is a very basic command.

In the default bash shell:

export PATH=$PATH:/your/path
For csh use:

setenv PATH $PATH:/your/path

Edit: Note that this is indeed the instructions for installing Java 6 and not Java 7, which is still - as of now - not available in any official repository or ppa.


I had no idea what Ubuntu Customization kit was, but I downloaded it so as to help you and I found out what causes the bug, I also found a solution to the problem, after a 5-6 min search of the code.
So, with some tricks on the code I managed to go till the screen that asks for the ISO, but I couldn't go further, as I didn't have an ISO downloaded, but I suspect that it should work fine from that point and after.
Ok, follow these steps:

Open a terminal (using Ctrl+Alt+T) and give: gksudo gedit /usr/lib/uck/gui.sh
Gedit will open.

Now, replace all the text in the opened file with this text: http://paste.ubuntu.com/961943/ (DO NOT select the numbers on the left)
Save the file and close gedit and terminal.

Re-run UCK.

Please let me now if it works further than selecting the ISO image, because I've tested till that point only (cause as I said before, I don't have an ISO to test it out!)
Also, note that this is not a permanent fix, it will probably cause some bugs in case you click 'Cancel' etc, but it will at least not crush and let you do the work.


Open a terminal (Ctrl+Alt+T) and type:

sudo rm /var/crash/*

Then hit Enter.

This will remove these crashes, that might still be reported.

New popups after a reboot need to be investigated.


Why won't this application start when I log in?

Try expanding the ~/Documents/StackApplet/stackapplet.py to the full path, using ~ in the path may not be supported in .desktop files.


1 You don't need to wipe your hard drive - Windows will do it for you (and sometimes when you don't even want it to /sarcasm)

2 You will wipe the hard drive completely, install Win7 using the entire hard drive. Once Win7 is completely installed and all the patches and updates are applied, then turn the calendar page to November (it only seems to take that long after installing Linux)

3 THEN  boot from a USB drive, CD or DVD containing Linux and install Linux, which will automatically calculate how to resize the disk drive partitions for you.


How to re-install rtl8188su in Ubuntu 20.04?

It is impossible to tell you anything without the details of what you did. If removing the kernel module that already existed for this dongle/card then you need to download the .deb for it and put the module back in its proper place or re-install the kernel if not wanting to extract the file manually. If trying to correct the no n wireless then it will never happen the driver does not support it.
https://manpages.ubuntu.com/manpages/xenial/man4/rsu.4freebsd.html


This answer uses primitive commands. Someone else might add another answer about tlp or other higher level utilities.
It isn't always the case that minimum CPU frequency means longest battery life. Sometimes completing a task faster, at higher CPU frequency, results in so much extra time in deep, low power, idle states, that energy is actually saved. The term for this is "race to idle". The highly non-linear portion of the performance/power curve is in the "turbo" region. Therefore often it is enough to simply disable turbo.
By default, your computer should be using the intel_pstate CPU frequency scaling driver and the powersave governor. Check via, and for example:
doug@s18:~$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_driver
/sys/devices/system/cpu/cpufreq/policy0/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpufreq/policy1/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpufreq/policy2/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpufreq/policy3/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpufreq/policy4/scaling_driver:intel_pstate
/sys/devices/system/cpu/cpufreq/policy5/scaling_driver:intel_pstate
doug@s18:~$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_governor
/sys/devices/system/cpu/cpufreq/policy0/scaling_governor:performance
/sys/devices/system/cpu/cpufreq/policy1/scaling_governor:performance
/sys/devices/system/cpu/cpufreq/policy2/scaling_governor:performance
/sys/devices/system/cpu/cpufreq/policy3/scaling_governor:performance
/sys/devices/system/cpu/cpufreq/policy4/scaling_governor:performance
/sys/devices/system/cpu/cpufreq/policy5/scaling_governor:performance

Oh, well let's fix that:
doug@s18:~$ echo powersave | sudo tee /sys/devices/system/cpu/cpufreq/policy*/scaling_governor
powersave
doug@s18:~$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_governor
/sys/devices/system/cpu/cpufreq/policy0/scaling_governor:powersave
/sys/devices/system/cpu/cpufreq/policy1/scaling_governor:powersave
/sys/devices/system/cpu/cpufreq/policy2/scaling_governor:powersave
/sys/devices/system/cpu/cpufreq/policy3/scaling_governor:powersave
/sys/devices/system/cpu/cpufreq/policy4/scaling_governor:powersave
/sys/devices/system/cpu/cpufreq/policy5/scaling_governor:powersave

Now, if turbo is not disabled in the BIOS, it will default to enabled, so disable it:
grep . /sys/devices/system/cpu/intel_pstate/no_turbo
doug@s18:~$ grep . /sys/devices/system/cpu/intel_pstate/no_turbo
0
doug@s18:~$ echo 1 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
1
doug@s18:~$ grep . /sys/devices/system/cpu/intel_pstate/no_turbo
1

By default HWP (HardWare Pstate) should be enabled on your computer, so you can also tell it to prefer power saving over performance:
doug@s18:~$ grep . /sys/devices/system/cpu/cpufreq/policy*/energy_performance*
/sys/devices/system/cpu/cpufreq/policy0/energy_performance_available_preferences:default performance balance_performance balance_power power
/sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference:balance_performance
/sys/devices/system/cpu/cpufreq/policy1/energy_performance_available_preferences:default performance balance_performance balance_power power
/sys/devices/system/cpu/cpufreq/policy1/energy_performance_preference:balance_performance
/sys/devices/system/cpu/cpufreq/policy2/energy_performance_available_preferences:default performance balance_performance balance_power power
/sys/devices/system/cpu/cpufreq/policy2/energy_performance_preference:balance_performance
/sys/devices/system/cpu/cpufreq/policy3/energy_performance_available_preferences:default performance balance_performance balance_power power
/sys/devices/system/cpu/cpufreq/policy3/energy_performance_preference:balance_performance
/sys/devices/system/cpu/cpufreq/policy4/energy_performance_available_preferences:default performance balance_performance balance_power power
/sys/devices/system/cpu/cpufreq/policy4/energy_performance_preference:balance_performance
/sys/devices/system/cpu/cpufreq/policy5/energy_performance_available_preferences:default performance balance_performance balance_power power
/sys/devices/system/cpu/cpufreq/policy5/energy_performance_preference:balance_performance

and:
doug@s18:~$ echo power | sudo tee /sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference
power
doug@s18:~$ grep . /sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference
/sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference:power
/sys/devices/system/cpu/cpufreq/policy1/energy_performance_preference:power
/sys/devices/system/cpu/cpufreq/policy2/energy_performance_preference:power
/sys/devices/system/cpu/cpufreq/policy3/energy_performance_preference:power
/sys/devices/system/cpu/cpufreq/policy4/energy_performance_preference:power
/sys/devices/system/cpu/cpufreq/policy5/energy_performance_preference:power

Now. if you still want to reduce the maximum CPU frequency, you can do it via two methods:
doug@s18:~$ grep . /sys/devices/system/cpu/intel_pstate/*perf_pct
/sys/devices/system/cpu/intel_pstate/max_perf_pct:100
/sys/devices/system/cpu/intel_pstate/min_perf_pct:17
doug@s18:~$ echo 17 | sudo tee /sys/devices/system/cpu/intel_pstate/max_perf_pct
17

Or:
doug@s18:~$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_m??_freq
/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:3700000
/sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq:800000
/sys/devices/system/cpu/cpufreq/policy1/scaling_max_freq:3700000
/sys/devices/system/cpu/cpufreq/policy1/scaling_min_freq:800000
/sys/devices/system/cpu/cpufreq/policy2/scaling_max_freq:3700000
/sys/devices/system/cpu/cpufreq/policy2/scaling_min_freq:800000
/sys/devices/system/cpu/cpufreq/policy3/scaling_max_freq:3700000
/sys/devices/system/cpu/cpufreq/policy3/scaling_min_freq:800000
/sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq:3700000
/sys/devices/system/cpu/cpufreq/policy4/scaling_min_freq:800000
/sys/devices/system/cpu/cpufreq/policy5/scaling_max_freq:3700000
/sys/devices/system/cpu/cpufreq/policy5/scaling_min_freq:800000
doug@s18:~$ echo 800000 | sudo tee /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq
800000
doug@s18:~$ grep . /sys/devices/system/cpu/cpufreq/policy*/scaling_max_freq
/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:800000
/sys/devices/system/cpu/cpufreq/policy1/scaling_max_freq:800000
/sys/devices/system/cpu/cpufreq/policy2/scaling_max_freq:800000
/sys/devices/system/cpu/cpufreq/policy3/scaling_max_freq:800000
/sys/devices/system/cpu/cpufreq/policy4/scaling_max_freq:800000
/sys/devices/system/cpu/cpufreq/policy5/scaling_max_freq:800000

Now, let's use turbostat to observe powers under some of these conditions, using prime95 torture test, the most brutal CPU stress program I know of:
$ sudo ./turbostat --Summary --quiet --show Busy%,Bzy_MHz,IRQ,PkgWatt,PkgTmp,RAMWatt --interval 6
Busy%   Bzy_MHz IRQ     PkgTmp  PkgWatt RAMWatt
0.28    800     320     32      2.07    1.89
2.17    800     1136    33      2.10    1.89
99.36   4088    36118   67      105.53  1.96 <<< level 2 power throttle alrady active
99.32   4131    36077   62      108.98  1.96
100.12  4071    36076   64      99.94   1.96 <<< level 1 power throttle, 100 watts.
100.12  4070    36074   65      99.92   1.96
100.12  4069    36078   65      99.94   1.96
100.11  4067    36106   65      99.92   1.96
100.11  4066    36077   65      99.91   1.96
100.11  4065    36091   65      99.93   1.96
100.11  4063    36177   65      99.92   1.93
100.10  4061    36072   65      99.93   1.90
100.10  4059    36083   65      99.92   1.90
100.14  3966    36254   58      93.05   1.90
100.26  3700    36109   58      72.93   1.90 <<< turbo disabled
100.26  3700    36073   58      72.94   1.90
100.26  3700    36087   59      73.19   1.89
100.26  3369    36298   49      60.96   1.89
100.26  2800    36081   49      39.78   1.89 <<< start reducing max CPU freq more.
100.26  2800    36076   48      39.82   1.89
100.26  2800    36202   48      39.76   1.89
100.26  2371    36128   45      30.00   1.89
100.26  2300    36168   45      28.30   1.89
100.26  2300    36262   45      28.20   1.90
100.26  1976    36122   43      22.39   1.90
100.26  1900    36072   43      20.99   1.90
100.26  1900    36071   43      20.95   1.90
100.26  1900    36205   43      20.96   1.90
100.26  1486    36122   40      14.81   1.90
100.26  1400    36100   40      13.55   1.90
100.26  1400    36073   40      13.54   1.90
100.26  1400    36205   40      13.60   1.90
100.26  1082    36116   39      9.83    1.90
100.26  1000    36076   39      8.89    1.90
100.26  1000    36195   38      8.88    1.90
100.26  878     36131   38      7.84    1.89
100.26  800     36075   38      7.19    1.89 <<< until lowest possible
100.26  800     36070   38      7.22    1.89
100.26  800     36086   38      7.26    1.89


Having an Issue in restricting length of password

This is a bit old but for in order to help others here's what I've found.

minlen is not just a basic character length restrictor, it it more a score that takes a number of criteria into account

source:

  The minlen complexity measure is calculated in a number of steps:

  every character in a password yields one point, regardless of the    type of character
  every lowercase letter adds one point, but only up to the value of lcredit
  every uppercase letter adds one point, but only up to the value of ucredit
  every digit adds one point, but only up to the value of dcredit
  every special character adds one point, but only up to the value of ocredit

What I was seeing was a minlen of 16 allowing passwords of 8 characters as I was getting 2 points per character typed.

This is also documented in man 8 pam_cracklib:

  The minimum acceptable size for the new password (plus one if credits are not disabled which is the
   default). In addition to the number of characters in the new password, credit (of +1 in length) is given
   for each different kind of character (other, upper, lower and digit). The default for this parameter is 9
   which is good for a old style UNIX password all of the same type of character but may be too low to
   exploit the added security of a md5 system. Note that there is a pair of length limits in Cracklib
   itself, a "way too short" limit of 4 which is hard coded in and a defined limit (6) that will be checked
   without reference to minlen. If you want to allow passwords as short as 5 characters you should not use
   this module.


Bluetooth keeps dropping connection to keyboard

Run this command and reboot

sudo tee /etc/modprobe.d/iwlwifi-opt.conf <<< "options iwlwifi bt_coex_active=N"

This should fix the issue with Wi-Fi and bluetooth coexistence.


fixed. I just installed PulseAudio volume control and it fixed it.


Using the command-line to publish your key you can run,

gpg --keyserver keyserver.ubuntu.com --send-keys yourkeyID

and then you should get the following notification:

gpg: sending key yourkeyID to hkp server keyserver.ubuntu.com

You can check it is present on the server by running the command given in this article:

How do I check if my OpenPGP key is in the Ubuntu keyserver?

You can also use the gui program, Seahorse, to manage your keys, which is the 'Passwords and Encryption Keys' program mentioned in the link you quoted, although you might have to install it now.

A more recent gpg tutorial is available at Ubuntu help, which goes through in some detail how to create, publish, and backup your GPG keys.


From ubuntu, how do you edit files created by juju?

Once you deploy the instances they are normal Ubuntu Server machines, so you can admin them any way you want to edit files.

Though keep in mind that many public providers do not open ports by default, so to get something like xrdp working you'd have to configure that afterwards.


Since you're running Ubuntu 16.04, you should consider running the native systemd suspend/hibernate services in lieu of the pm-utils tools.

In my own case, here's what I've done to configure my machine for hibernate/resume using systemd:

In etc/default/grub, configure GRUB_CMDLINE_LINUX_DEFAULT to include
the resume parameter, passing the UUID of the swap partition in
question (i.e., resume=UUID=453f0121-505d-42d3-8dad-87f913e67ddc). My
current GRUB_CMDLINE_LINUX_DEFAULT is

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pci=nomsi resume=UUID=453f0121-505d-42d3-8dad-87f913e67ddc"
Run sudo update-grub
Edit/confirm resume=UUID=453f0121-505d-42d3-8dad-87f913e67ddc entry
in resume file located in /etc/initramfs
Run sudo update-initramfs -u
Edit /etc/systemd/logind.conf to set HandleLidSwitch=hibernate (optional: permits hibernate to start on lid close)
Run sudo service systemd-logind restart
Reboot for good measure

I've bold-faced the two parameters that--for my machine--are important: pci=nomsi and resume=UUID=[your swap partition]. While the latter parameter is pretty well understood and is often refenced when talking about enabling hibernate on a Debian system, it took a bit of discovery to find the need for the former.

Best of luck!


Laptop gets stuck after closing lid on after upgrading to Ubuntu 19.10

Not sure if it is the same problem but since i've upgraded to Xubuntu 19.10 when I closed and open my laptop lid the graphical window became non-responsive. I could see the mouse cursor moving otherwise the screen is frozen.

Removing the screensaver service from the startup seems to have solved the problem. Hope it helps on regular Ubuntu too.


Is it safe to install old libraries? Wine issue

First, try installing the 64 bit version to see if that will resolve the problem. Run the following command:

sudo apt-get install libstdc++5

Please post any more errors.

EDIT:

Okay, then install the i386 version like so:

sudo apt-get install libstdc++5:i386

Please post any more errors.


How to install Android Studio in Ubuntu Touch

Sadly, Android Studio has not been compiled for the ARM arch, so you won't be able to install it.

It would probably perform terribly anyway, since ARM CPUs aren't very powerful.


ClipIt keeps synchronizing primary selection with Ctrl+C even after closed/disabled, how to fix?

ok, I had parcellite, clipit and diodon installed.

I removed clipit and parcellite as diodon history begin working.

even after removed and closed (the indicator), parcellite was still running, I pkill it.

now the problem is solved.

I think we must chose only one to keep installed and running, make sure others arent running (even after uninstalling), and it will work correctly again.


What is the default encoding, used in text files in Ubuntu?

There is a tool called enca which you can use to detect and convert the encoding technique.
From the manpage

Enca reads given text files, or standard input when none are  given,  and  uses  knowledge
about  their  language  (must  be  supported by you) and a mixture of parsing, statistical
analysis, guessing and black magic to determine their encodings, which it then  prints  to
standard output (or it confesses it doesn't have any idea what the encoding could be).
Enca can also convert files to some other encoding ENC when you ask for it--either using a
built-in converter, some conversion library, or by calling an external converter.


Error when trying to update ubuntu using sudo apt-get update

First try

sudo apt-get -f install

If this does not help you, then try the following.

Check which package causing the problem by this command.

sudo dpkg --audit

Then reinstall or reconfigure it.


Export gpodder subscription list via command line

Enter gpo

You will get

gPodder 3.10.1 (2018-02-19) - http://gpodder.org/
Copyright 2005-2018 The gPodder Team
License: GNU General Public License, version 3 or later

Entering interactive shell. Type 'help' for help.
Press Ctrl+D (EOF) or type 'quit' to quit.

After typing help, you will see that you need to enter

export backup.opml

type exit to exit the interactive mode

The file backup.opml will be saved in your home folder.

You can also enter:

gpo export backup.opml


Why is 'auto eth0' a problem to Kernel > 3.2?

If you declare 'auto eth0' in /etc/network/interfaces, you are telling the system to connect the ethernet automatically. But then, as you said, you have disconnected the ethernet cable. You have given the system an impossible task: to connect the ethernet but without a cable connection to the router! The system will try to follow your instructions for several minutes and will eventually boot without the connection you requested.

Usually, Network Manager will handle all this for you with no entries in /etc/network/interfaces except for loopback. If that is not happening, you will have better luck troubleshooting NM rather than giving the system an unresolvable problem.


2 possible causes:

hardware error regarding power supply that can come from an older or bugged BIOS. If it is use pcie_port_pm=off as a boot parameter and it should circumvent it (but not fix it). If that works add it to the line GRUB_CMDLINE_LINUX_DEFAULT (sudo gedit /etc/default/grub). It can have side effects so test it out from grub command 1st. More on how to do this.

driver error. If this is the cause reloading it should work
modprobe -r igb
sleep 1
modprobe igb
sleep 1
systemctl restart network

In that case you might want to add these lines somewhere in the boot process.


are ubuntu specific packages capable of installing on lubuntu?

The packages are the same for Ubuntu, Lubuntu or Xubuntu. The only difference is the default desktop environment.
You should respect the distribution versions though, LUbuntu 64 12.04 for Ubuntu 64 12,04 for example.


I found the solution:

All my servers are behind proxy, And I needed to add all Proxy related certificate to that specific node which I ma trying to deploy charm, using this command:

Obtain the certificate(s) in Base64 encoded X.509 format.

    1. Copy them to /usr/local/share/ca-certificates

    2. If the extension is not .crt rename the files.

    3. sudo update-ca-certificates


When I run Android SDK from terminal, it shows error. How to fix it?

Credit to Ubuntu Forums:

sudo mount -o remount,exec /tmp


DNS-Settings on Network-Manager when using VPN

I googled here and have exactly the same issue too. (Ubuntu 19.04)

For me, this answer solved.

nmcli c modify <vpn-settings-name> ipv4.dns-search '<domain>'

You should specify <vpn-settings-name> that corresponds to a VPN setting name in GUI.
And <domain> is the domain name you want to search via DNS in the remote network.

After reconnecting to VPN, systemd-resolved status ppp0 shows

Link 6 (ppp0)
      Current Scopes: DNS
DefaultRoute setting: yes
       LLMNR setting: yes
MulticastDNS setting: no
  DNSOverTLS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
  Current DNS Server: 192.168.1.1
         DNS Servers: 192.168.1.1 (<--- my dns)
                      192.168.1.10
          DNS Domain: corp


I used the find command without specifying a directory

Ubuntu uses GNU find,  which assumes current working directory if you don't specify one. Specifically, it assumes . and all items that are found by the command will have ./ prefix to their path when passed to -exec command. So it would only traverse /var/www/html;  if your current working directory really was in /var/www/html nothing outside of that would be affected.  Other implementations of find may require directory argument as BSD find for example.

However, as mature's answer mentioned, your syntax is incomplete, hence that command wouldn't run. The \ at the end would tell the shell the command is incomplete and show PS2 prompt which is >


windows system (bootloader) partition accidently deleted during multiple installs

There are two paths to take:
Getting into Windows

Boot a Ubuntu Live CD, and open Gparted. Right-click n your Windows partition(the one containing boot.ini, select the option to change flags, and ensure the boot flag is set.

Download and burn Super Grub Disc(Not SGD2) and boot to it. Edit: gave correct link as first was SGD2 due to my stupidity

Select Windows in the SGD menu, and then in the submenu that appears, select "Fix Boot of Windows".

Reboot.

Getting Ubuntu working along with Windows

Unfortunately, you need to have a separate Ubuntu partiton. If you can "unmerge" the partition in any way, then boot a live CD and open the Linux partition you have(It'll be on the left bar of the file manager, but not the root partiton, as that is the one used by the Live CD.

Open a terminal. Enter in the terminal:
grub-install --root-directory=<Mount point of Linux partition> /dev/sda

You may get the mount point by opening Disk Utility(Palimpsest). Once you execute the command, Grub will be installed, hopefully recognizing the Windows partition. If you need to remove Grub and use the Windows loader, you will lose access to Ubuntu.(unless you chainload, which is outside the scope of this answer)

Consider having Grub on an external drive and booting to it to load Ubuntu, if nothing else works.
Edit: On SGD, I believe I may not have given perfect instructions. Try:Super Grub Disc->Choose Language and no Help->English->Windows->Fix Boot of Windows? If that fails, try the Activate partition option for your system(Desktop vs Laptop).


First, try disabling Secure Boot. If it's enabled, some versions of GRUB can't boot Windows. This is a GRUB bug.

If that doesn't help, try installing my rEFInd boot manager. You can try the USB flash drive or CD-R image without installing it, if you like; or dive in all the way by installing the Debian-package version in Ubuntu. (Note that the USB flash drive/CD-R version will boot Ubuntu correctly only if you do not have a separate /boot partition or if you manually edit your kernel options.) rEFInd is less finicky about booting Windows than is GRUB, so it's more likely to work if GRUB gives you problems.

If you prefer to stick to GRUB, that may be possible, but you'll need to provide more details about what's not working, like any error messages you're getting, whether you see a Windows logo appear, etc.

Sometimes this problem can be caused by a missing Windows boot loader. (Typically you'll get some variety of "file not found" message, or rEFInd won't show a Windows option at all, if this is the case.) You'll need to either restore the Windows boot loader files from a backup or use a Windows emergency disc to re-install the files to fix this problem.


How can i increase the size of the window buttons on Xubuntu?

Those buttons are changed by changing to a different window manager theme. In XFCE's Settings, under Window Manager & the first Style tab:

Just click on a different theme and see the change immediately. The package xfwm4-themes has more themes.

Editing a specific theme could in theory change their size, unless they're static images, but it's probably much easier to just pick a different theme with bigger buttons. Looking at xfwm4-themes installed files, it might be one of the .xpm files, similar to /usr/share/themes/Wallis/xfwm4/top-right-active.xpm.

A little experimentation reveals that some themes have only images, some have only .xpm files ("text images"), and some have both. There's several files for each "state" for example the close button has "closed-active", "closed-inactive", and -prelight, -pressed.

Copying a button's set from one theme's xfwm4 directory to another's seems to copy that button only.

.xpm files may be able to be directly edited, the first few lines are similar to:

/* XPM */
static char * maximize_active_xpm[] = {
"18 29 2 1",

where the 18 appears to have something to do with the width, and 29 height, but maybe in an "offset" somehow. gimp might be able to edit them...


Custom Desktop Launchers not sticking after restart in Unity 2D panel

Desktop configuration files are not necessary for Unity or Unity 2D.
Just launch programs you like in the launcher. Then right click on their icon in the launcher and mark "Keep on launcher".


Regarding installation of Ubuntu in phone

No, Ubuntu OS & Ubuntu touch can only be installed on phone which has android.
No Nokia Symbian phones, No Lumia(Windows) phones, No Apple Iphones. Only on phones which are capable of Android (With dual core processor & minimum of 512mb INTERNAL RAM).


How to compile msmtp from source, install in the proper location and install a service startup script for 18.04?

First, /usr/local is usually where manually installed packages go (/usr/local/bin). This will override any packages in /usr/bin or other directories used by apt installed packages.

Next, install the build dependencies:

sudo apt build-dep msmtp

Now, cd into the msmtp directory and run the following commands:

make clean
./configure
make
sudo make install

This will install to the correct location which is /usr/local. When you install to this directory, you do not need to uninstall the apt version so that packages that depend on msmtp will not break. When you or the system runs msmtp, the version in /usr/local will be used.

To uninstall, cd into the msmtp directory and run the following command:

sudo make uninstall


Solution as extracted from the comments:

Steps to find the cause involve checking...

memory/cpu usage (e.g. using top to look at the processes using most of it)
disk activity (first check the disk LED, then iotop from the iotop package proves helpful)

In most cases, one of these two steps identify the process lagging the system. Depending on what it is, further actions can be evaluated (stopping/killing that process or, as in this case, re-organize cron jobs causing heavvy activity to not have them all run at the same time in parallel).


Unable to Install NVIDIA drivers for RTX 2080

In UEFI systems the Secure Boot feature prevents loading unsigned drivers.

The Nvidia proprietary drivers are unsigned therefore Secure Boot wouldn't allow them resulting in an "unclaimed" status. The installation of Nvidia drivers also blacklisted the open-source nouveau that would have otherwise "claimed" the graphics card.

Solutions are (1) disable Secure Boot at UEFI -or- (2) sign the Nvidia drivers.


How do I revert to 11.04's version of Nautilus?

Nautilus in oneiric requires the GTK+3 libraries whereas Nautilus in Natty requires the GTK+2 libraries - quite different.

I'm afraid this will not be easily possible - you will need to recompile and probably have to do major code surgery... it's far easier just to stay with 11.04 if this emblem function is a major capability you require until a Gnome 3 alternative is developed.

workaround

Please see this Q&A for a scripted workaround:

Is there any tweak to bring back emblems in Nautilus?


I also have Sony WH-1000XM3 and micro's bad quality it's not related to Ubuntu. I tested it with Android mobile and another PC with Windows. On all devices mic quality is the same.


How can I rotate my laptops built in display?

It looks like you have two outputs: XWAYLAND1 and XWAYLAND2.

Because your external monitor is 23 inches or 584.2 milimeters (XWAYLAND1), I assume your built-in-display is XWAYLAND2.

Use this command instead:

xrandr --output XWAYLAND2 --rotate inverted


It's pretty easy to setup, I use a bluetooth keyboard and have used this method.

The tool you are looking for is grub-reboot with good instructions found HERE


gnome ppp installation without connection

It is always better to install a package using apt or Software Center. It installs the package along with all its dependencies. But it needs active connection.

To install a package offline you need to download the package along with all its dependencies on a system where internet connection is available. Next you need to copy the downloads to your offline system in order to install them.

To do this you can go to packages.ubuntu.com and search for gnome-ppp. Don't forget to choose correct distribution. Download the .deb file with appropriate architecture.

Make sure you have all the dependencies shown in the gnome-ppp page already installed in your system. Most probably you need to download and install wvdial, other dependencies should already there. Download the .deb file for wvdial also, if not pre-installed on your system.

To check a package/dependency is installed in your system, run the following command in terminal,

dpkg -l | grep <packagename>

For example, to check wvdial is there or not use,

dpkg -l | grep wvdial

If you have it on your system the output will be like,

ii    wvdial    1.61-4build1    intelligent Point-to-Point Protocol dialer

Before you proceed to install check all the dependencies are installed in your system (if not you need to download each of them from the above site and install).

Installation:

First you need to install the dependency(s). Then gnome-ppp itself. To install a package run in terminal,

sudo dkpg -i /path/to/<packagename.deb>

Hope this will be helpful.


what does this mean "80/tcp filtered http"

For what I can read from the NMAP manual there are 6 states (at least for NMAP):

Open State

An application is actively accepting TCP connections, UDP datagrams or SCTP associations  on this port. Finding these is often the primary goal of port scanning. Security-minded   people know that each open port is an avenue for attack. Attackers and pen-testers want to exploit the open ports, while administrators try to close or protect them with firewalls without thwarting legitimate users. Open ports are also interesting for non-security scans because they show services available for use on the network.

Closed State

A closed port is accessible (it receives and responds to Nmap probe packets), but there is no application listening on it. They can be helpful in showing that a host is up on an IP address (host discovery, or ping scanning), and as part of OS detection. Because closed ports are reachable, it may be worth scanning later in case some open up. Administrators may want to consider blocking such ports with a firewall. Then they would appear in the filtered state, discussed next.

Filtered State

Nmap cannot determine whether the port is open because packet filtering prevents its probes from reaching the port. The filtering could be from a dedicated firewall device, router rules, or host-based firewall software. These ports frustrate attackers because they provide so little information. Sometimes they respond with ICMP error messages such as type 3 code 13 (destination unreachable: communication administratively prohibited), but filters that simply drop probes without responding are far more common. This forces Nmap to retry several times just in case the probe was dropped due to network congestion rather than filtering. This slows down the scan dramatically.

Unfiltered State

The unfiltered state means that a port is accessible, but Nmap is unable to determine whether it is open or closed. Only the ACK scan, which is used to map firewall rulesets, classifies ports into this state. Scanning unfiltered ports with other scan types such as Window scan, SYN scan, or FIN scan, may help resolve whether the port is open.

Open & Filtered State

Nmap places ports in this state when it is unable to determine whether a port is open or filtered. This occurs for scan types in which open ports give no response. The lack of response could also mean that a packet filter dropped the probe or any response it elicited. So Nmap does not know for sure whether the port is open or being filtered. The UDP, IP protocol, FIN, NULL, and Xmas scans classify ports this way.

Closed & Filtered State

This state is used when Nmap is unable to determine whether a port is closed or filtered. It is only used for the IP ID idle scan.

So in your case, the filtered state might be because some packet filtering software might be blocking/preventing the detection. This could be a firewall, router, ip rules, etc.. You could start disabling each one, one at a time to quickly see which one is the one causing the problem.


Realtek wifi driver problem rtl8723be weak signal

I found the solution for this

open terminal and run

iwconfig

Note down the wlp number, in my case it was wlp13s0

Now download the driver from this link

And unzip and copy it to the Desktop. The final result should be like you should have a folder named rtlwifi_new-rock.new_btcoex  in Desktop.

Now go back to terminal and cd to that folder. that is

cd Desktop
cd rtlwifi_new-rock.new_btcoex

Now run these commands 1 by 1

make
sudo make install
sudo modprobe -rv rtl8723be
sudo modprobe -v rtl8723be ant_sel=2

By now your wifi should be strong and start working, but follow below commands to make the settings permanent

sudo ip link set wlp13s0 up
sudo iw dev wlp13s0 scan
echo "options rtl8723be ant_sel=2" | sudo tee /etc/modprobe.d/50-rtl8723be.conf

This should fix the wifi and no reboot required.


There are several special keyboards that bring Multimedia Keys, specially Application Keys, which include keys that have the Logo for Word, Excel, Powerpoint, Thunderbird and even... yes... Internet Explorer. When pressed, they open the app assigned to it. In Ubuntu of course this would open the Libreoffice Apps (Calc, Writer, Impress, Firefox, Thunderbird...).

The key that has the "Browser" logo, is known as the WWW key or WEB key because it opens your computer to the World Weird Web. If you keyboard has it, it will open the browser that you have set as default. Firefox is the one that comes by default but you can change this in the System Settings. Here are some images of how the key looks:

If you do not have the WWW Key, then it will simply not work. You would need to reassign the key to another value. Same thing for Volume Control, where it has Volume Down/Up, Pause and Play assign to other keys not available on my keyboard, so I need to reassign them. Here is how it looks for me on a keyboard that has no multimedia or special keys:

With this I can use CTRL with the combination of a Numeric Key (The +, -, /, * signs) and I can control the volume and any music player.


Changing network interface names or better yet how does it work?

Try this :

sudo ifconfig enp2s0 down
sudo ip link set enp2s0 name eth0
sudo ifconfig eth0 up

Answer from michel_04 found here : https://forum.ubuntu-fr.org/viewtopic.php?id=2007521

I actually also had to modify /etc/network/interfaces


How to programmatically find the current value of DISPLAY when DISPLAY is unset? (for use in crontab)

You can't for sure. You have to make assumptions.

Pretend you're cron and you're facing the worst case scenario for a second: there are multiple users logged in, and each user is running multiple X sessions. You'll have to guess the user (easy enough, we're executing their crontab) and one of that user's X sessions.

If we want to assume the user is running one and only one X session from a tty, and get that session's $DISPLAY value we can use w:

USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
user     tty1                      16:32    7:15   0.21s  0.19s -zsh
user     tty2     :1               15:52   48:13   2:17   0.08s /sbin/upstart
user     pts/3    :1               16:19    0.00s  0.66s  0.00s w

For example here I'm logged in on tty1, on tty2 (where I'm running an X session) and on pts/3 (the terminal from which I'm running the command).

With a bit of parsing:

% w $(id -un) | awk 'NF > 7 && $2 ~ /tty[0-9]+/ {print $3; exit}'
:1

So, assuming all the above:

0 0 * * * DISPLAY=$(w $(id -un) | awk 'NF > 7 && $2 ~ /tty[0-9]+/ {print $3; exit}') command

Will make cron execute command with $DISPLAY set to the first X session running in a tty's $DISPLAY value found for the user.


KInfocenter - Information About This System

KDE git: https://cgit.kde.org/kinfocenter.git/

For  the customization the about-distro module is reading information from the kcm-about-distrorc configuration file.

kinfocenter/Modules/about-distro/README:

  See example/*.

  Essentially you place an rc file in the file system that defines the
  distro logo and website url. The file ought to be in some
  XDG_CONFIG_DIRS dir.

  e.g. pkexec cp pwd/example/kcm-about-distrorc.ex
  /etc/xdg/kcm-about-distrorc

XDG Base Directory Specification: https://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html

kinfocenter/Modules/about-distro/example/kcm-about-distrorc.ex

[General]
LogoPath=/home/me/kubuntu-circle-small.png
Website=http://www.kubuntu.org
Version=1.2.3
Variant=Unstable Branches

Example S.H.A.D.O
($HOME/.config/kcm-about-distrorc as the users configuration files take precedence over system entries of /etc/xdg/kcm-about-distrorc)

[General]
Name=S.H.A.D.O
LogoPath=/usr/share/about-distro/SHADO-logo.png
Website=https://en.wikipedia.org/wiki/UFO_(TV_series)#SHADO
Version=123
Variant=Secret

KInfocenter will show:


I used the method from the second answer here: Ubuntu 12.04 alsamixer not found

sudo addgroup <username> audio


Where does a PC (Ubuntu 14.04 LTS here) store WiFi passwords?

Wireless passwords are indeed stored on the hard drive, in something known as a "connection profile." Connection profiles, essentially, have everything the system requires to connect to every network. However, they also contain a field to identify which device the profile belongs to:

When the system tries to establish a connection using the profile it has for that WiFi network, it notices that the device IDs don't match, and therefore the profile is skipped. As no valid profile is discovered, the system assumes that the WiFi network is new and hasn't been used before. Therefore, none of the settings for the network exist, and you have to re-enter your password.

If you'd rather not re-create a new wireless profile, you can always change the device using the Connection Editor (Edit Connections under the Wi-Fi icon), which will then allow that profile to be used with the new device. From here, you can also set other parameters for your network, as well as extract the wireless password in plaintext if need be.

If you're more adventurous and want to (ab)use the command line, connection profiles are all stored in /etc/NetworkManager/system-connections, which contains (roughly) the same information as the GUI does:

[connection]
id=[Human-Friendly Connection Name]
uuid=[Connection ID]
type=wifi
permissions=user:kazwolfe:;
secondaries=
timestamp=1482791037

[wifi]
mac-address=[Device MAC]
mac-address-blacklist=
mac-address-randomization=0
mode=infrastructure
seen-bssids=[List of known BSSIDs]
ssid=[Network SSID]

[wifi-security]
group=
key-mgmt=wpa-psk
pairwise=
proto=
psk=[Network Password]

[ipv4]
dns-search=
method=auto

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
ip6-privacy=2
method=auto

Note that these files are owned by root because they contain sensitive information, and as such, sudo is required to be able to access or edit them. Also note that while the filenames in this path are usually the SSID, this is not a hard-and-fast rule. Therefore, you might need to do a bit of poking around to find your network.


Thinkpad X1 Carbon wakes up from sleep automatically

In the Bios, in the category "Power", there is a feature called

  Intel (R) Rapid Start Technology

Which tries to enter a more efficient sleep state after being asleep for (by default) an hour. You could try to disable this option.


Xubuntu: How to prevent applications/programs from showing hidden files when opening or saving files?

Have you tried right clicking on the open file selection box and deselecting "Show Hidden Files"?
Obvious maybe but the "hidden files" option for file selection boxes in applications is different than that of your file manager.


Ubuntu partition with windows 10 "windows failed to start"

You can shutdown your machine. Then power it on while repeatedly pressing the function key appropriate for your machine to bring the bios screen. For Lenovo it is F2, for HP it is F12. Go to boot option. Move to windows using arrow keys. Use F6 to bring it to top. Use F10 to save and exit. Now the machine should boot fine.

If it doesn't then you can enter your windows CD, go to BIOS, then boot option. Here you will see an entry for Windows CD. Move it to top, save and exit. You can now repair your windows without any problem. Hope it helps.


If I understand correctly, I think this is what you are looking for:
$ echo "This is the pattern : th_now(5), almost done!" | sed 's/th_now(\([^()]*\))/th_now_\1/'
This is the pattern : th_now_5, almost done!

Or:
$ echo "This is the pattern : th_now(5), almost done!" | sed 's/th_now(\([[:digit:]]*\))/th_now_\1/'
This is the pattern : th_now_5, almost done!


Remove snap-store without removing snapd

Oh.. I just did it...
I ran

joe@uOS:~$ sudo snap remove gtk-common-themes
gtk-common-themes removed
joe@uOS:~$ snap list --all
Name             Version                     Rev   Tracking  Publisher   Notes
core             16-2.42.1                   8039  stable    canonical✓  core
core18           20191030                    1265  stable    canonical✓  base
gnome-3-28-1804  3.28.0-16-g27c9498.27c9498  110   stable    canonical✓  -
micro            0+git.af520cf               648   stable    zy          classic
snap-store       20191114.a9948d5            209   stable    canonical✓  -
joe@uOS:~$ sudo snap remove snap-store
snap-store removed

joe@uOS:~$ sudo snap install gtk-common-themes
gtk-common-themes 0.1-25-gcc83164 from Canonical✓ installed
joe@uOS:~$ sudo snap install snap-store
snap-store 20191114.a9948d5 from Canonical✓ installed

Perfect it runs... but I wonder why did that ever happen...


Have you had this problem?
Write the following in the terminal:
rm -r ~/.cache/spotify && rm -r ~/.config/spotify

Note: This will clear all local Spotify settings. Playlists, ratings, etc. should not be affected.
Then restart spotify, and it's all. :-D


Searching for a filename without a certain string

Add a ! (not) before the expression:

sudo find path ! -name '*xyz*'


Install VNC on Ubuntu 14.04 Desktop edition

Ubuntu comes with a VNC client pre-installed, so you don't actually have to download or install anything. It's called Remmina and is pretty awesome. At least, I haven't had any problems with it. I can control all the PC's on my LAN including the Windows machines as well as tunnel a VNC session through SSH in order to securely connect to my work computer over the internet.

Ubuntu also has a VNC server pre-installed. To set it up just search for "desktop sharing".


Video and audio scrolling not work when using HTML5 audio on a webpage

If by "scrolling" you mean "seeking", then I believe the issue is that the current Ubuntu One file server doesn't support HTTP Range requests, which is needed to seek when playing HTML5 video or audio.


"Serious errors found HF checking the drive for /home" After Moving /home to external HFSplus partition

The last column in the /etc/fstab line you've added is fsck options. "1" means the order in which fsck should check the partition.

You probably don't want to check that filesystem from Linux - try changing the line to

/dev/sda3 /home hfsplus defaults 0 0

and see if it helps.


A complete answer depends on the firmware in your MB.
Two suggestions are;

Look at your firmware options and see if there is an option to boot into an EFI shell.  If so boot into the shell and modify the contents of the NVRAM using the bcfg shell command.  The first option is to look at the contents of the NVRAM using bcfg boot dump which will display all NVRAM boot options.  You can the use other bcfg commands to add entries.  The bcfg commands can be found in the UEFI Shell Commands Manual. From memory it will be something like bcfg boot add ?????  where ???? is the path to a bootloader.  Be aware that this path must be able to be read by the EFI firmware and a valid bootloader must be present in this location. It is usually in the EFI Partition which is normally a GPT Fat formatted partition.  Once you create a valid NVRAM entry you cab boot into that OS and use the OS tools (like efibootmgr) to further modify the NVRAM values.
If there is no firmware option to boot into an EFI Shell then try to restore the efi firmware defaults (probably called the BIOS Defaults) in your systems MB firmware.  This should restore NVRAM entries for things like Optical Drive, HDD's, and USB devices.  You may have to ensure that there are valid UEFI bootloaders on the optical and USB drives.

If all else fails I recommend reading about UEFI booting on Rod Smith's excellent pages on the subject.  Google Rod Smith Refind as a starting point.


Ubuntu software download query - difference between vdi and iso file types

A VDI file file.vdi is a file, that is made for virtual machines. It is typically used to provide a virtual file system by VirtualBox, where Ubuntu and other operating systems can be installed in a virtual machine.

VirtualBox is an application program, that runs in a host operating system (for example Ubuntu or Windows). You create a virtual machine, and a VDI file to provide an 'internal disk' in the virtual machine, where you install a guest operating system. This link shows some useful details.

Please notice that you can boot a virtual machine directly from an iso file.
An iso file file.iso is a file, that is made in order to create a bootable drive in a CD/DVD disk and/or a mass storage device (usually a USB pendrive or memory card but also an SSD or HDD). The partition structure and file system is iso 9660, which is read-only, and the idea is to copy/expand the stored file system into RAM, to run the operating system.

Most main linux distros, including Ubuntu, provide hybrid iso files, which can be burned to a DVD disk and cloned to a mass storage device (usually a USB pendrive) and the result will be a bootable drive, that will run a live-only version of the operating system for testing and/or installing the operating system into an internal drive in the computer.

This link helps with some more details.


Very slow Ethernet connexion on Ubuntu 20.4 Realtek

sudo ethtool enp4s0
Settings for enp4s0:
Supported ports: [ TP MII ]
Supported link modes:   10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes:  10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: Symmetric Receive-only
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Link partner advertised link modes:  10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Half 1000baseT/Full
Link partner advertised pause frame use: Symmetric Receive-only
Link partner advertised auto-negotiation: Yes
Link partner advertised FEC modes: Not reported
Speed: 1000Mb/s
Duplex: Full
Port: MII
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: d
Current message level: 0x00000033 (51)
drv probe ifdown ifup
Link detected: yes
lspci | grep -i eth
04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 11)
The Ethernet cable connexion is very poor, what can i do ? Thank you


Booting kernel failed : Invalid argument

I faced the same problem. My VMware version was 12. So I checked Md5 checksum of my ISO file. But They were different. I found that the ISO file was not downloaded perfectly and a problem happened. So I tried downloading again. Then installation was completed finally.


Still not able to drag and drop files in my web file /var/www

Make sure /var/www is writeable, for the user you have opened your X session with.

Alternatively, open a terminal, try to copy your data using cp -rp ~/Downloads/xx /var/www. Maybe you'll have some error message showing.

To ensure your user may write to /var/www, use:

sudo chown myuser /var/www


How to clone Ubuntu 16.04 partition from triple booted HDD to SSD?

clonezilla is an excellent disk/partition clone program.

get a live boot image here: http://clonezilla.org/

download the image and burn it to cd.boot from the cd.

the program has a grapfical inteface that guides you through it.

the cloned partition will have the same uuid as the original,
so log into ubuntu and use gparted to generate a new uuid for the clone.

last update grub to get the new ubuntu added to the menu.


for(( i = 0; i<=5; i++)) is Bash specific and doesn't work with plain Bourne shell (/bin/sh).

If you remove the shebang the script is run by your current shell (which likely is Bash) so it works.

Replace #!/bin/sh with #!/bin/bash to make the shebang work.


/etc/hosts modification does not work properly. What to do?

I can confirm your problem that it appears to affect, between both, Chrome and Firefox, only Firefox. This is an answer for users that are affected by the same problem and if they are affected by both/all browsers. Follow this steps to have this working correctly. Assuming you already edited /etc/hosts file to which I recommend the following 2 ways to edit the file:

Gedit - gksudo gedit /etc/hosts (You now have a GUI friendly way of editing the file. gksu which provides gksudo is discontinued in the official 18.04 and later repositories.)
nano - sudo nano /etc/hosts (You now have a terminal friendly way of editing the file.)

And you have for example:

127.0.0.1 localhost adobe.com

or

127.0.0.1 localhost
127.0.0.1 adobe.com

(Both are the same thing.)

You first test this out to see if it is working correctly from the terminal. Type ping adobe.com and it should respond from the IP assign to it. In this case it should respond with 127.0.0.1. That means it is OK.

Then we continue with the browser tests.  You tested Chrome and it worked. You changed /etc/hosts between having and not having the entry for adobe.com and it worked every time you changed it. But then you went with Firefox, it might have worked the first time, but after changing hosts file back and forth it somehow stop working. This means it is a cache problem or a problem resolving the correct name.

In the case of Firefox and resolving the name, Firefox adds the the prefix www to the adobe website so it looks like this "www.adobe.com" but on Chrome it looks like this "adobe.com". They both point to the same place and the www prefix is just there to tell you that the place you are visiting is a web service. But in the case of your problem you would need to add that to the hosts file so when Firefox adds the prefix www it works. So it would look like this:

127.0.0.1 localhost
127.0.0.1 adobe.com www.adobe.com

OR just the same

127.0.0.1 localhost adobe.com www.adobe.com

NOTE: Remember that you HAVE TO press F5 to refresh the site/Firefox tab or close the tab and open it again to test. Somehow pressing Enter like crazy won't do.

This should solve the problem for some users, but assuming up to now you still have not yet solved the problem, we can test out what could it be.

We got here a couple of levels of cache to check then. You got your program Cache, in this case Firefox, then you have your System Cache, in this case Ubuntu, and then you have your hardware cache, in this case your router.

For what I know, the Ubuntu Desktop version does not have a DNS cache service installed by default. The most commonly known is nscd and if you had that installed a simple /etc/init.d/nscd restart will do. But for most people they will not have this installed, so we can overrule the Ubuntu system's fault.

That leaves the router and web browser. In the case of the router you would have to configure it to stop DNS cache or reconfigure it to solve this issue. This totally depends on the Router model, manufacturer, etc. Not all routers do DNS cache, but some do and you would need to see in the configuration of it, if it has this option and if the option is enabled. But let us assume you do not have a DNS Caching enabled router.

This leaves the browser.

To find out if Firefox is being bad with DNS Cache you can install an Add-on to check DNS Cache in Firefox. the one I recommend is DNS Cache.

After restarting Firefox you should see a cog in the bottom (Similar to the Ubuntu cog in the upper right corner). You can left-click or right-click the Cog and you should see options like Enable/Disable DNS and Flush it. This will help in the case of the problem being the Firefox DNS Cache. Play with it.

I think I got all the ways you could solve that. If I missed something, let me know.


It comes from a 3rd party PPA and can still be installed.  Run the following from a terminal window:

sudo add-apt-repository ppa:atareao/atareao
sudo apt update
sudo apt install cpu-g

The command sudo apt update may not be required due to when you run the first command in Ubuntu 18.04 it automatically should run the update line once the PPA is added.

Hope this helps!


Here it's my fix:

Run in terminal: sudo apt-get install vnc4server
Run in terminal: vnc4server (a message will appear in the terminal)
Finally run: vncconfig and allow the clipboard.

For me it doesn't fix the clipboard between PC and server but it fix it between server and PC. It's something :)


It is OK. Just type the password and press Enter. The password you enter would not be shown even in star shapes because of security issues. For example if sb watches your monitor during entering password, he/she never can find the number of characters in your password


I don't know which virtual machine software you are using but in Oracles's Virtualbox you have to enable a share clipboard folder option. You can see how to do it here.

Another option is to use winscp. If you are familiar with scp command in linux is exactly that with a gui interface. This way you can transfer files via ssh. Open winscp and connect just as you were ssh'ing. You can modify your files locally and then transfer them to your virtual machine.

Hope this helps.


Firstly you appear to have downloaded a deb file for Karmic and your question is about Oneric. According to the Remastersys website you should be using version 3.0.0-1

  For Lucid and Newer - version 3.0.0-1
  Remastersys for Lucid and newer
  deb http://www.remastersys.com/repository/lucid/

I recommend you have a read through the documentation on the site for Ubuntu, especially the notes about the dist and the backup options. If you follow the steps and recommendations correctly it should work ok.


Grub menu still shows after Ubuntu uninstallation

You can remove GRUB on make default bootloader as window using Easy BCD on Windows. You can customize all bootloaders with Easy BCD


Unity 3D only show wallpaper and Icon if set, where did it go?

Try following some of these instructions:

http://www.tuxgarage.com/2011/04/missing-top-and-side-panels-in-unity.html

Hope this helps,

Leinardo


Error - Package 'pulseaudio' has no installation candidate

for a long shot
software-properties-gtk

Go to Tab updates and activate bionic-updates and bionic-security.
sudo apt update && sudo apt install pulseaudio


The only build for Trusty is the current unstable build. That might be fine or you could build the development copy from source. This is all extremely documented. Here's how I'd install from the unstable packages:

Download the SDK deb installers and install.
Optionally do the same for the samples (same link)
Follow the tutorial to test the samples.
Continue following the manual to learn more about it.


Is there a program that I can use to find my drivers?

@Noclip726 Go to Search your computer and online sources and type Software Updater Click on that and it will directly install any available updates.ORYou can open Terminal by Typing "Ctrl+Alt+T" and Run sudo apt-get updateHope you will be able to install all softwares.


Is it possible to run the IIS web server on Linux?

IIS is Microsoft-proprietary web server software that can only run in the Windows operating systems for full support of it and all of its features.  It is not capable of being run in a non-Windows environment without sacrificing some functionality, and you will need Windows Server or Windows 7 with IIS installed on it in order to use IIS and all of its features.


Asus Table T100HA webcam does not work with Ubuntu 20.04 LTS

I had the same problem on a desktop machine with a USB webcam. After 20.04 upgrade there's no webcam shown with lsusb and no files seen at /dev/video.
I fixed it by uninstalling Cheese:
sudo apt-get remove cheese

I installed guvcview:
sudo apt-get install guvcview

Then unplugged and replugged the USB webcam and ran  guvcview.
Files have now appeared at /dev/video0 and /dev/video1. The webcam appears when I run lsusb and is functioning in Google Meet and Zoom.


Comparing the contents of two directories

You can use the diff command just as you would use it for files:

diff <directory1> <directory2>

If you want to see subfolders and -files too, you can use the -r option:

diff -r <directory1> <directory2>


Unable to Install ubuntu onto a blank hard drive

Have you tried to run the installer after choosing the "Try Ubuntu" option? After the system loads, on the desktop there should be an icon for the bootdisk installer. Use that to start the install process, then please update your question with progress, if any.


How to install Ubuntu OS Having already installed Windows

Yes...

here's how to do it-

When you boot the LIVE CD/USB for installation, you will get 3 options like the picture below-

1st option will resize your windows partition and install ubuntu with it.
2nd option will erase the complete disk and install ubuntu(YOU DONT WANT TO DO THIS)
3rd option will let you select the drive/partition to install in.(SELECTING THIS IS RECOMENDED)

The procedure below is for option 3-

Click on the 3rd option - Do something else.

That will take you to a partition table.

In the partition table you will see your partitions.
 - The 1st one will be c drive which has windows.You will be able to see it as NTFS file system.

If all are NTFS,mostly the 1st partition will be C drive.

  keeping the size of the  partitions different e.g 230 and 270 etc will help you easily recognize your c drive because there are no labels like c or d there)

Then select from the other drives the drive which you want to use for ubuntu.

Get some free space to install :

Caution : Below steps is for deleting . Deleting a hard disk partition will make all files inaccessible everything in that partition, be sure to take back up if any.

Select that drive(other than the WINDOWS c DRIVE) from the partition table and click on DELETE. That partition will be deleted and you will see unallocated space.

Caution : Below steps is for formatting. Formating a hard disk partition will permanently erase everything in that partition.

Now,you can either directly make the complete partition as EXT4 for installing Linux or you can also add a SWAP partition.

  It is always recommended to add a SWAP area for better performance but only if your ram is below 8gb

Step 1 : Create a SWAP partition

Select the new unallocated space or free space, click on add.
Assign the space from that partition to SWAP AREA equal to double your ram.(e.g-for  1gb,swap area-2gb) But if you have large RAM like 4GB or 6GB you can assign 1GB as swap.
Select SWAP AREA from the file system drop down menu.
Make sure Beginning is selected in the partition position drop down menu.
Click on add.

Adding root file system

Now, after you have added the SWAP AREA,do this-

Select the remaining "Unallocated space" and click on ADD.
Select Ext4 Journaling file system from the file-system dropdown menu.
Select Primary from the partition type drop-down menu.
Select the mount point as / from the mount-point drop-down menu.
Select beginning from the Position drop-down menu.
Click on add.

After adding the partitions,from the table select the ext4 partition you see and tick in the corresponding check-box(if not already ticked)

then Select INSTALL...


Why are hard links not allowed for directories?

Directory hardlinks break the filesystem in multiple ways

They allow you to create loops

A hard link to a directory can link to a parent of itself, which creates a file system loop. For example, these commands could create a loop with the back link l:

mkdir -p /tmp/a/b
cd /tmp/a/b
ln -d /tmp/a l

A filesystem with a directory loop has infinite depth:

cd /tmp/a/b/l/b/l/b/l/b/l/b

Avoiding an infinite loop when traversing such a directory structure is somewhat difficult (though for example POSIX requires find to avoid this).

A  file system with this kind of hard link is no longer a tree, because a tree must not, by definition, contain a loop.

They break the unambiguity of parent directories

With a filesystem loop, multiple parent directories exist:

cd /tmp/a/b
cd /tmp/a/b/l/b

In the first case, /tmp/a is the parent directory of /tmp/a/b.
In the second case, /tmp/a/b/l is the parent directory of /tmp/a/b/l/b, which is the same as /tmp/a/b.
So it has two parent directories.

They multiply files

Files are identified by paths, after resolving symlinks. So

/tmp/a/b/foo.txt
/tmp/a/b/l/b/foo.txt

are different files.
There are infinitely many further paths of the file. They are the same in terms of their inode number of course. But if you do not explicitly expect loops, there is no reason to check for that.

A directory hardlink can also point to a child directory, or a directory that is neither child nor parent of any depth. In this case, a file that is a child of the link would be replicated to two files, identified by two paths.

Your example

$ ln /Some/Direcoty /home/nischay/Hard-Directory
$ echo foo > /home/nischay/Hard-Directory/foobar.txt
$ diff -s /Some/Direcoty/foobar.txt /home/nischay/Hard-Directory/foobar.txt
$ echo bar >> /Some/Direcoty/foobar.txt
$ diff -s /Some/Direcoty/foobar.txt /home/nischay/Hard-Directory/foobar.txt
$ cat /Some/Direcoty/foobar.txt
foo
bar

How can soft links to directories work then?

A path that may contain softlinks and even soft linked directory loops is often used just to identify and open a file. It can be used as a normal, linear path.

But there are other situations, when paths are used to compare files. In this case, symbolic links in the path can be resolved first, converting it to a minimal, and commonly agreed upon representation creating a canonical path:

This is possible, because the soft links can all be expanded to paths without the link. After doing that with all soft links in a path, the remaining path is part of a tree, where a path is always unambiguous.

The command readlink can resolve a path to its canonical path:

$ readlink -f /some/symlinked/path

Soft links are different from what the filesystem uses

A soft link cannot cause all the trouble because it is different from the links inside the filesystem. It can be distinguished from hard links, and resolved to a path without symlinks if needed.
In some sense, adding symlinks does not alter the basic file system structure - it keeps it, but adds more structure like an application layer.

From man readlink:

 NAME
        readlink - print resolved symbolic links or canonical
        file names

 SYNOPSIS
        readlink [OPTION]... FILE...

 DESCRIPTION
        Print value of a symbolic link or canonical file name

        -f, --canonicalize
               canonicalize by  following  every  symlink  in
               every component of the given name recursively;
               all but the last component must exist
        [  ...  ]


Boot your Ubuntu system and then enter in the terminal:

sudo grub-install /dev/sda


How do I set an extra IP for an existing interface?

Instead of that eth0:0 business, you should do this:

Configure your (one) static IP address in /etc/network/interfaces as you normally would:

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.0.201
network 192.168.0.0
netmask 255.255.255.0
broadcast 192.168.0.255
gateway 192.168.0.1

Add another IP to this interface by adding this right after the above:

up /sbin/ip addr add 192.168.0.203/24 dev eth0
down /sbin/ip addr del 192.168.0.203/24 dev eth0

The complete file should look like this

Now, if you check what IP addresses are configured by running ip addr show, both will show up:

2: eth0:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 08:00:27:1d:fa:0b brd ff:ff:ff:ff:ff:ff
    inet 192.168.0.201/24 brd 192.168.0.255 scope global eth0
    inet 192.168.0.203/24 scope global secondary eth0

My thanks to Lekensteyn for pointing me in the right direction. Every site on the internet just talks about eth0:0 for a secondary IP address. This seems like the proper way to do it.


MATE was forked on purpose to stay with Gtk2, for reasons of performance and maintainability; a desktop with similar panel arrangements but using Gtk3 is Cinnamon.
See Why was MATE created on the Linux Mint forums.

When running Gtk3 applications in MATE you'll notice they look different, unless you are using a theme that supports both Gtk2 and Gtk3, with sensibly a similar look. You'll have to select the theme in both Preferences/Aspect applet for Gtk2 and gnome-tweak-tool for Gtk3.


Boot fails after "Checking battery state"

I got a solution... same thing happened to me... may be while installing some package it uninstalled gnome-power-manager.

just get into shell by keying in ctrl+alt+F5 or F6 it will take you to login prompt

get in and type

sudo apt-get install ubuntu-desktop

Volla !!!

everything is fine... you get back your gui.


can't log in , even after trying to boot through a DVD with downloaded Ubuntu 14.04

Burn a DVD/pendirve with the desired Ubuntu distro. Put it in your laptop and reboot. Follow the instructions to perform a fresh installation.

IMPORTANT NOTE: you will loose all your data if you format partitions.


Somehow I created a nondeterministic sh script

More specifically, pipes are not deterministic.

I.e. in a pipe such as this one:

command1 file | command2 | command3 >file

it's not guaranteed that command1 file will be executed before command3 >file.

So the race condition between command1 file and command3 >file makes it so that sometimes the file is first read by command1 file and sometimes the file is first truncated by command3 >file, giving the expected output in the first case and a giving an empty output in the second case.

This can be fixed by using sponge (in the moreutils package) to write the output to the file, to make sure that the output gets written to the file only after the rest of the pipe has finished executing:

command1 file | command2 | command3 | sponge file


There was some problem with Annonaceae buildd and it should be fixed now.
See http://irclogs.ubuntu.com/2011/11/14/%23ubuntu-arm.txt


Where do I get the source code for Ubuntu Light?

The repository for Dell-based projects is here:

http://dell-mini.archive.canonical.com/updates

For Ubuntu Light as shipped on the Inspiron M101Z specifically you want this URL:

http://dell-mini.archive.canonical.com/updates/dists/lucid-omsk/public/


Numpad doesn't work after booting up - forced to reconnect USB keyboard after startup

There is a Numlock button on your keyboard that activate the numerical keypad, if not activated the numerical keypad is used to move into documents (there should be arrows on the keys). On Windows XP this button is activated by default at startup, on Ubuntu it isn't. Just press the Numlock button after startup.

If it is a problem for you, then here is how to fix it :
https://help.ubuntu.com/community/NumLock


This question was answered in the comment section by @Terrance:

  I found this in another post, but I am not able to validate it myself,
  but does this work? System Settings > Desktop Effects > All Effects >
  Show FPS


Can I run exodus wallet on Ubuntu 14.04 LTS?

Looking at the website, the Exodus wallet for Linux downloads as a zip archive containing a binary file.

Here is how you can download/install Version 1.27.2:

$ wget https://exodusbin.azureedge.net/releases/Exodus-linux-x64-1.27.2.zip
$ unzip Exodus-linux-x64-1.27.2.zip
$ exodus-1.27.2/Exodus-linux-x64/Exodus

And Exodus now installs!


Blank screen at the beginning of the installation

Boot to Win 8, reinstall ihr ISO to your pen drive again with PENDRIVELINUX(google it), boot again with your pendrive

OR

Get to Ubuntu with the pen as a live USB and try installing ubuntu from there dude.


I have no ideas , but :

teoria says that 32bit win can host a 64 bit ubuntu , but i suppose that this make some mess .
try to use a 32 bit ubuntu version .


Started tightvncserver on Ubuntu, but viewer complains about missing .xsession file

I was able to resolve this.  The key was focusing on my ~/.vnc/xstartup file.  Instead of running Xsession, I now have it run fvwm and it's working well enough now.


Cannot connect to Wi-Fi Ubuntu 18.04 (Secure boot disabled)

We see this in your paste results:

  rtlwifi-new, 0.6, 5.0.0-32-generic, x86_64: installed (WARNING! Diff
  between built and installed module!)

Let's remove the dkms version and see if the installed version works better. From the terminal:

sudo dkms remove rtlwifi-new/0.6 --all

You may also need to specify the antenna connection to use. Please do:

sudo -i
echo "options rtl8723de ant_sel=2"  >>  /etc/modprobe.d/rtl8723de.conf
exit

Reboot.


From the source code of the gedit terminal plugin (/usr/lib/x86_64-linux-gnu/gedit/plugins/terminal.py) it seems the settings are read from /org/gnome/terminal/legacy/profiles first. On my machine (Ubuntu 16.04) there is some key group containing only the two values "scrollback-unlimited" and "use-theme-transparency".
The keys "foreground-color", "background-color" and "palette" were missing from the default profile.

The terminal plugin assumes incorrectly that all required keys are present if you create a new profile from gnome-terminal. To enforce complete key creation you need to switch back and forth between different palette settings and I also had to create two profiles and switch "Edit/Preferences/Profiles/Profile used when launching a new Terminal" back and forth as well (this ensures that the key org.gnome.terminal.legacy.profiles/default is set).

However, I think that settings under "org.gnome.gedit.plugins.terminal" should have precedence over the system settings concerning the terminal plugin in gedit. The user may want one color scheme for the system terminal and a different one for the terminal plugin.

So finally I changed the python script function get_profile_settings back to how it was in previous Ubuntu versions (just added the comment #) and got the desired result.

def get_profile_settings(self):
#        profiles = self.settings_try_new("org.gnome.Terminal.ProfilesList")
#        if profiles:
#            default_path = "/org/gnome/terminal/legacy/profiles:/:" + profiles.get_string("default") + "/"
#            settings = Gio.Settings.new_with_path("org.gnome.Terminal.Legacy.Profile",
#                                                  default_path)
#        else:
        settings = Gio.Settings.new("org.gnome.gedit.plugins.terminal")

        return settings


I believe the issue is connected with gpu-manager, still not found a solution for anyone interested, but here is the log file, when intel is selected
:
log_file: /var/log/gpu-manager.log
last_boot_file: /var/lib/ubuntu-drivers-common/last_gfx_boot
new_boot_file: /var/lib/ubuntu-drivers-common/last_gfx_boot
can't access /run/u-d-c-fglrx-was-loaded file
Looking for fglrx modules in /lib/modules/4.4.0-43-generic/updates/dkms
Looking for nvidia modules in /lib/modules/4.4.0-43-generic/updates/dkms
Found nvidia module: nvidia_361.ko
Is nvidia loaded? yes
Was nvidia unloaded? no
Is nvidia blacklisted? yes
Is fglrx loaded? no
Was fglrx unloaded? no
Is fglrx blacklisted? no
Is intel loaded? yes
Is radeon loaded? no
Is radeon blacklisted? no
Is amdgpu loaded? no
Is amdgpu blacklisted? no
Is nouveau loaded? no
Is nouveau blacklisted? yes
Is fglrx kernel module available? no
Is nvidia kernel module available? yes
Vendor/Device Id: 8086:1916
BusID "PCI:0@0:2:0"
Is boot vga? yes
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Skipping "/dev/dri/card0", driven by "i915_bpo"
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Skipping "/dev/dri/card0", driven by "i915_bpo"
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Skipping "/dev/dri/card0", driven by "i915_bpo"
Skipping "/dev/dri/card1", driven by "nvidia-drm"
Found "/dev/dri/card0", driven by "i915_bpo"
output 0:
    card0-eDP-1
Number of connected outputs for /dev/dri/card0: 1
Does it require offloading? yes
last cards number = 2
Has amd? no
Has intel? yes
Has nvidia? no
How many cards? 1
The number of cards has changed!
Has the system changed? Yes
main_arch_path x86_64-linux-gnu, other_arch_path i386-linux-gnu
Current alternative: /usr/lib/nvidia-361/ld.so.conf
Current core alternative: (null)
Current egl alternative: /usr/lib/nvidia-361/ld.so.conf
Is nvidia enabled? yes
Is nvidia egl enabled? yes
Is fglrx enabled? no
Is mesa enabled? no
Is mesa egl enabled? no
Is pxpress enabled? no
Is prime enabled? no
Is prime egl enabled? no
Is nvidia available? yes
Is nvidia egl available? no
Is fglrx available? no
Is fglrx-core available? no
Is mesa available? yes
Is mesa egl available? yes
Is pxpress available? no
Is prime available? yes
Is prime egl available? no
System configuration has changed
Single card detected
Selecting mesa
/usr/bin/update-alternatives --set x86_64-linux-gnu_gl_conf /usr/lib/x86_64-linux-gnu/mesa/ld.so.conf
update-alternatives status 0
Calling ldconfig
ldconfig status 0
/usr/bin/update-alternatives --set i386-linux-gnu_gl_conf /usr/lib/i386-linux-gnu/mesa/ld.so.conf
update-alternatives status 0
Calling ldconfig
ldconfig status 0
/usr/bin/update-alternatives --set x86_64-linux-gnu_egl_conf /usr/lib/x86_64-linux-gnu/mesa-egl/ld.so.conf
update-alternatives status 0
Calling ldconfig
ldconfig status 0
Error: no alternative found for unblacklist
Removing xorg.conf. Path: /etc/X11/xorg.conf
System configuration has changed

I see that nvidia is swiched to black list and it removes my xorg.config file

which is diffrent from the time when i reboot and nvidia is automatically selected


how do i install ubuntu onto a pre made partition?

There could be a few issues occurring. I would recommend doing the following:

Run a disc check to ensure there are no errors on the Ubuntu CD/USB you created
When choosing "something else" during the install, delete the partitions you had created for Ubuntu and start over. I do the following:

  /dev/sdaX linux-swap 4GiB (or half the amount of ram you have)

    /dev/sdaX / 20 GiB - (this is your root)

      /dev/sdaX /home (rest of disk space /home partition is also optional)

I format all my partitions to Btrfs format as well, this runs the smoothest for me.

Ensure that you have your power supply as well as a good Ethernet connection plugged in.

As installation can take some time and if you are running a live CD/USB you want to be sure your Internet connection is consistent for the install.

Then follow the installation as normal. Sometimes depending on the amount of ram installed and your graphics card, it can take about thirty minutes or so to install.


Notebook MSI GT640 - noisy fan - Ubuntu 11.10 x64

I'm sorry to only add upon this complaint, but I have the exact same issue and have had even larger issues with other distro's. I wanted to know if this had anything to do with the new 2nd gen i7 / the threading or architecture , or just another HP heat issue. It is depressing because I worry about physical damage at the temp it runs at under medium load and may have to consider switching to VM for the mean time.


Just from browsing the logs, it looks like its missing the zmq headers. Have you tried sudo apt-get install libzmq-dev first?

Actually, it looks like there is a python3-zmq package, perhaps installing it first would allow the pip3 install jupyter to proceed.


Why does my Dell 1130n printer not install?

Ubuntu does not include a driver for your printer.

A google search tells me that Dell's 1130N is actually a rebadged Samsung ML-2580n with customised firmware.
What generic driver did you actually use? Paste the output of this command on a terminal: grep -H '^*NickName:' /etc/cups/ppd/*.ppd

Can you try weather the splix driver for the Samsung ML-2580N, which is included with Ubuntu, works good or better than the generic driver with your printer?
Go to system-config-printer (System -> Administration -> Printing in GNOME classic, Gear icon at the upper right of the screen -> Printers in Unity), right click your Printer and select Properties > click Change... next to the Make and Model field to see the available drivers and change it to Samsung ML-2580N.


You can install it using Ethereum's ppa:

sudo add-apt-repository -y ppa:ethereum/ethereum-qt
sudo apt install libqt5webengine5

Here I saw somebody complaining about problems occurred after installing libqt5webengine5, hence please be careful about which packages are going to be installed and which are going to be removed.