First things first:

If you want your data. DON'T do any writing to the card as you try the rescue.

I just happened to have the same problem on a friends PC with an external HDD which got its volume entries corrupted and was also only showing a few MB instead of 60 GB. This happened because he did not safely remove the drive from his PC. If your card is really broken then nothing except a professional rescue service will be of any help to get your data.

Step 1: open a terminal window

Simply press ctrl+alt+t to open a terminal window.

Step 2: acquire testdisk

testdisk is available in the normal Ubuntu repositories so simply install it by:

sudo apt-get install testdisk

Step 3: rescuing your data via testdisk

Insert your SD-card into your card-reader or plug in the drive you want to rescue and fire up teskdisk with:

sudo testdisk

Then you will see the following in your terminal window:

Here you can choose to create a log file which I highly recommend for eventual troubleshooting. Simply press enter and you will see the next in your terminal, where you can choose the drive you want to rescue:

Of course you see my drives in the screen-shot so you have to navigate to the corresponding drive with the up and down arrow key and then select at the bottom proceed with the left and right arrow key and hit return.

Next you will see is the file-system selection like in the next screen-shot:

In most cases it tells you in the hint at the bottom which file-system type to select, do so or set it to the corresponding type of your drive. Then hit return again to proceed.

In the next menu (see screen-shot) select 'Advanced' and you should be able to see the full partitions (maybe a second partition on your card). Select it and select 'List' files and back them up.

You should then see the directory structure you had on your drive like in the next screen-shot:

See the red ones on the screen-shot; these are deleted files you can choose to hide by pressing h. Now navigate to the files/directories you want to rescue by pressing up and down arrow key (you can switch directories with enter or go upward by selecting the .. entries.

To make a selection of which files you want to copy/rescue press : which will mark the corresponding row green or press c to copy a single file. For copying the selection press shift+c. In both cases you will then be prompted with another directory view where you can navigate to a place to save your data/files. Navigate to where you want to have this data and press shift+c again to start copying.

Step 4: cleaning your SD-card

After you have all your data rescued its time to clean up the SD-card so you can use it again to full capacity. To do this just enter the following in your terminal (make sure you select the right volume for your card which was sdb in your screen-shot so I take that for my example here)

sudo dd bs=4m if=/dev/zero of=/dev/sdb

This may take a while to run but after that there is nothing on the SD-card at all so you should be able to use it with your reader and simply format it again.


Connecting Ubuntu 14.04 and OS X 10.10.3 Via Ethernet Cable

As sharing the folders which containing the files is possible scenario i recommend samba configuration on ubuntu which will setup shared folder due to which you can simply copy paste whichever file you like from both ubuntu to mac or vice-versa
samba installation in ubuntu


Have you tried switching tty before logging in?

Restart your system and do not log in.
When presented with login, press CTRL+ALT+F8

This will bring you to a black login screen

Login as root
usermod -d /path/to/new/home -m username
Press CTRL+ALT+F7 to return to X tty (or reboot)

This should bring you back to your GUI.
I'm pretty sure that Ubuntu puts X on tty7, but used to be tty6.

Login as username.

If you're not familiar with your root password, you can change it so that you are able to login as root (sudo passwd).


I cannot install applications because Ubuntu cannot set the locale?

It seems that you have 3 distinct problems here.

A half-installed postgresql-9.3 seems to be on the system, so when you try to apt-get install any new package, it tries to finish the postgresql install first. This is the normal APT behavior.
The permissions of /var/run/postgresql are incorrect, hence the error
could not create lock file "/var/run/postgresql/.s.PGSQL.5433.lock": Permission denied, which whould happen even if the rest was OK.
Your locale settings en_US.UTF-8 are borked, as if someone deleted underlying files, hence the advice from @Zanna to regenerate them with sudo locale-gen en_US.utf8

If you're primarily interested in fixing #1, I think you want to uninstall the half-installed postgresql-9.3

In your case, I would start by a command like this:

dpkg-query -W -f='${db:Status-Abbrev}\t${binary:Package}\n' 'postgres*'

To obtain the list of postgres packages and their status. Then uninstall and purge the ones that are in error or half-installed.


How can I deploy a new ssh key to hosts after adding it in the maas admin account?

I don't think MAAS has the ability to push a new key to an already-deployed node. Are you sure there was not a single key imported to your account when you deployed the node?


install issue opengl Mesa-10.2.6 cannot find llvm shared libraries

I think you have to do

sudo apt-get install llvm-dev


Ubuntu cannot upgrade via terminal nor the sofware updater applications

You are currently running version 16.10 (Yakkety Yak) which is a standard release that reached end of life in July 2017.  Standard releases come out every 6 months and have a fast upgrade cycle: they are only supported for 9 months.  It is expected for users on this upgrade cycle to upgrade within 3 months of a new release.

By comparison, LTS (long term support) releases, like 16.04.6 (Xenial Xerus), are released every two years and are supported for at least 5 years.

See Releases - Ubuntu Wiki for a complete list of releases and support dates.

The reason you are getting errors from apt because apt is attempting to get updated packages for Yakkety Yak, but most mirrors are no longer hosting anything for that version of Ubuntu. Instead all package information has been moved to Old Releases.

You should still be able to upgrade your current installation by using a live CD or bootable USB image of the version you want to upgrade to. There should be an option to upgrade during installation on the "Allocate drive space" prompt.

As of this answer, the most recent standard release is 19.04 and will be supported until January 2020. The most recent LTS release is 18.04.2 which will receive support until April 2023, and extended security maintenance (ESM) from Canonical for an additional five years to 2028.


I don't think that 140TB kcore is a problem.

As gropiuskalle said in one forum: "/proc/kcore is an image of your RAM created by the Kernel to give you respective information, it's not actually a file you could delete but a virtual filesystem and it does not actually take harddisk-space."

Also, mine kcore has the same size as yours:

That doesn't mean you don't have other problem caused by an interruption of gparted.

Regards.


Downloading Ubuntu, Removing wrecked OS and Windows 10

To create a bootable Ubuntu USB drive, you can follow these steps, depending on what Operating System you are currently using:

Ubuntu: https://tutorials.ubuntu.com/tutorial/tutorial-create-a-usb-stick-on-ubuntu#0

Windows: https://tutorials.ubuntu.com/tutorial/tutorial-create-a-usb-stick-on-windows#0

Once you've created the USB drive, boot from it and run the Ubuntu installer. When you're prompted for "Installation Type" select "Erase Disk and install Ubuntu". This will remove everything on your hard disk, including all files so make sure you've backed everything up.

Just as a note, there's no such thing as non-Debian Ubuntu - Ubuntu is based on Debian.


Google Chrome not starting ("Aborted (core dumped)")

I had the same issue and someone advised me to remove ~/.gtkrc-2.0 which did fix it for me. No idea why though.


Unable to mount nfs share to /var/www in fstab

I resolved the error, I also use webmin to manage both server and workstation via the webui. to resolve I navigated to the disk and network filesystems module of webmin and edited the nfs share for the /var/www automount, in the settings for the share I set Allow users to mount this filesystem to yes and saved. then clicked on share in dolphin and it opened as the /media shares do. I did not have to do this for the /media shares so somewhat unsure of why this happened, if anyone can share some info it would be appreciated.
Thanks


What is dev-sda.device in systemd-analyze, can i disable it?

You can't disable it, because /dev/sda7 is where your root partition is mounted. In systemd, everything that it can handle while booting is made into a systemd unit. Then you can do things with it (like track timings in this case, or depend on it for services). In the cases of devices, the chain goes like this:

the kernel loads the device and activates it
systemd watches for this and creates the /dev/sdxy nodes for it
then systemd activates the various mount units generated from fstab
which then triggers various other services which were waiting for filesystems to be mounted
and so on

This does allow you to identify that the disk is slow to activate, but unless you can get a new disk, there's not much you can do about it.

You can try analysing the critical path and see if there's anything else you can fix:

systemd-analyze critical-chain [UNIT...]  prints a tree of the
time-critical chain of units (for each of the specified UNITs or for
the default target otherwise). The time after the unit is active or
started is printed after the "@" character. The time the unit takes to
start is printed after the "+" character. Note that the output might be
misleading as the initialization of one service might depend on socket
activation and because of the parallel execution of units.

Example:

graphical.target @10.868s
└─multi-user.target @10.868s
  └─squid-deb-proxy.service @10.816s +51ms
    └─network-online.target @10.814s
      └─NetworkManager-wait-online.service @2.419s +8.395s
        └─NetworkManager.service @2.243s +155ms
          └─dbus.service @2.192s
            └─basic.target @2.129s
              └─sockets.target @2.129s
                └─snapd.socket @2.127s +1ms
                  └─sysinit.target @2.127s
                    └─swap.target @2.127s
                      └─dev-disk-by\x2duuid-498d24e5\x2d7755\x2d422f\x2dbe45\x2d1b78d50b44e8.swap @2.119s +7ms
                        └─dev-disk-by\x2duuid-498d24e5\x2d7755\x2d422f\x2dbe45\x2d1b78d50b44e8.device @2.119s

For example, in my case the network is slowing startup.


How do I resolve Debian packaging issue with ${python:Depends}?

Most likely from dh_python2, which guesses dependencies based on the requires.txt file in egg_info. This file is created from install_requires in setup.py by distutils / setuptools.

You can disable reading requires.txt by putting:

override_dh_python2:
    dh_python2 --no-guessing-deps

in your debian/rules. Or you can help it by putting

alembic alembic

in debian/pydist-overrides (I think).


How to recover USB flash drive functionality after having used dd?

In the following steps I am assuming as an example that you want to restore an 8GB USB flash drive to usable condition after writing the Ubuntu iso to it using dd, although of course the exact size of the USB flash drive is not important. The results of these steps are reproducible. I reformatted 2 USB flash drives with the following steps after writing Ubuntu ISOs to them with dd. As a side remark, it's kind of annoying to use dd instead of a GUI program like Startup Disk Creator, but dd is the only program I have found that works for writing the Ubuntu Minimal CD to a bootable USB flash drive.

Remove all of your USB devices except for the 8GB USB flash drive that you want to reformat, so you won't get confused about the device name of the USB flash drive later on.

List all the partitions.
 sudo fdisk -l

Search the results of the command for output that looks like this:
 Disk /dev/sdc: 7864 MB, 7864320000 bytes
 30 heads, 33 sectors/track, 15515 cylinders, total 15360000 sectors
 Units = sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disk identifier: 0x00016288

    Device Boot      Start         End      Blocks   Id  System
 /dev/sdc1   *        2048    15359999     7678976    b  W95 FAT32

If you see something like 7864 MB (8GB) in the output (see the example output above), then that is your 8GB USB flash drive. In this example it is called /dev/sdc. Now open the Disks application from the Dash and check again to make sure that the device name of your 8GB flash drive is the same as what you got from running the command: sudo fdisk -l.

Create a partition table on the disk of type msdos, sometimes known as Master Boot Record (MBR).
 sudo parted /dev/sdc mklabel msdos

In this example I used /dev/sdc for the name of the device which is what was found in the results of step 2. I can't stress strongly enough how important it is to verify the device name before running this step!
Warning: If you type the wrong device name you may overwrite your operating system or another one of your partitions containing important personal files!!! So be careful and check the device name a second time. Open the Disks application and check the device name of your 8GB USB flash drive in Disks. It should be the same device name!!! Now check again! You don't want to accidentally type the wrong device name!

Add an empty "primary" partition, which will hold a FAT filesystem later.
 sudo parted -a none /dev/sdc mkpart primary fat32 0 8192

Once again in this example I used /dev/sdc for the name of the device which is what was found in the results of step 2. The command specifies the start point (from 0 MB) to the end point (8192 MB). If the 8GB USB flash drive does not have the full 8192 MB space, parted will adjust it automatically. If the terminal returns a message that the start point can't start at 0 MB and you have to use some other small number close to 0 MB, type Y to accept this. Note the command is creating a single, primary partition on the whole disk.
This newly created partition will have the ID /dev/sdc1. That is because the device name in this example is /dev/sdc and the 1 at the end is because it is the first partition on that device.

Create a FAT filesystem on the /dev/sdc1 partition by formatting the partition.
 mkfs.vfat -n "8GB-USB" /dev/sdc1

/dev/sdc1 is the partition ID from step 4. "8GB-USB" is the partition label, which can be your own choice of label, just enclose the label inside two double quote characters.

You now have a ready-to-use reformatted USB flash drive with an 8GB FAT partition.


Installed Ubuntu 14, Monitor shuts off at boot

As per our conversation above, here is what you can do to permanently add the "nomodeset" parameter:

sudo nano /etc/default/grub

Find the line that says GRUB_CMDLINE_LINUX, and insert the parameter there just like you did with temporarily altering the command line, for example add it after the "quiet" parameter that most likely is there.

Now update the grub configuration:

sudo update-grub

Then reboot the system, your parameter will be automatically added at boot.


Looking for a school admin app for Ubuntu

Have you ever heard of Edubuntu? Edubuntu is an official Ubuntu flavor. Its target is Education, classrooms, schools and communities. It has quite a few tools for this, maybe one of them is what you're looking for? Take a look at

https://www.edubuntu.org/

It also uses the Unity Desktop, so you won't feel much difference in the userland.


Galaxy S not detected, how do I make it work?

Mine works.

Heres what you have to do.

On phone goto Settings->Wireless and network->USB settings
Change option to Mass storage or Ask on connection
Connect phone to Ubuntu PC
If you clicked on Ask on connection select mass storage on your phone

Your phone should now be recognized.


Failing to start mysql.service for MySQL 5.6 on Ubuntu 16.04

After Downgrading MySQL version I am also facing this try following command

systemctl unmask mysql.service
service mysql start


Installation -- No Internet Connection Option

I'm having the same issue, so are many others. I did a little search, discovered this:

http://www.upubuntu.com/2012/10/how-to-fix-unity-and-wireless-problems.html

I have not tried it yet. Seems to work for others though. Good luck.


That's called an OEM install, and it is covered on help.ubuntu.com.


du can accept a list of files or directories from stdin (or sufficiently new versions can, anyway). So you can use find and friends to filter and provide this list:

find Pictures -mindepth 2 -type d \( -execdir test -f '{}/0k' \; -o -print0 \) |
  du --files0-from=- -h

With -mindepth 2, find will only list directories (-type d) at least two levels deep (so Pictures/*/*)
In each of these directories, find will run test -f "{}/0k", which simply tests for existence of a file named 0k. ({} will be replaced by find with the directory.)

If the test succeeds, nothing happens. If not, the directory path is printed with an ASCII NUL at the end (-o print0).
The way -o works, the execdir and -print0 need to be grouped using (, ).

du will then take these directory names and happily provide disk usage.

Sorting:

find Pictures -mindepth 2 -type d \( -execdir test -f '{}/0k' \; -o -print0 \) |
  du --files0-from=- -h |
  sort -rh


Can I install 64-bit Eclipse on 32-bit Ubuntu?

No. You can install 32-bit software on an x64 bit machine but you can not install x64 based software on a 32-bit machine.

http://www.techsupportalert.com/content/32-bit-and-64-bit-explained.htm

This rule applies to all Operating Systems.


how to i make a live ubuntu on my usb with persistence that can boot both from pc and mac?

You could use UNetbootin,

sudo apt-get install unetbootin

The process is easy from there.


Ubuntu 18.04. Can boot normally in Ubuntu (graphic mode) but get stuck in Recovery Mode

In grub I changed GRUB_CMDLINE_LINUX="" to GRUB_CMDLINE_LINUX="console=tty12" to hide kernel text as suggested here.

After removing console=tty12 I could boot into recovery mode.

Tried this three times (adding and removing console=tty12) with same result.


Just install the default-jre package:

sudo apt-get install default-jre

Or use your favourite package manager (Synaptic, Ubuntu Software Centre, Aptitude, etc.)


Booting windows 10 after deleting linux dualboot partition

Prepare a bootable USB drive/CD/DVD with the exact same version Windows that you got installed on your PC. Boot from that CD/DVD/USB. Select your language and press Next. Then click on Repair your computer option in bottom left. Now you have to find and open Command Prompt. It is usually under Advanced options in Windows 8,8.1,10.
In the Command Prompt run these commands-

bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd
exit

Then restart your PC.
Note: This will only work on BIOS/MBR based dual-boot system. If you have UEFI based dual-boot follow this link.


Files is nautilus, just under a different name. For some reason nautilus devs have removed a lot of features in the latest release hence the lack of proper right click menu and script support. If you want the old nautilus back I would suggest installing "nemo", a fork of the old version by the guys at linux mint. To do this run:

sudo add-apt-repository ppa:gwendal-lebihan-dev/cinnamon-stable
sudo apt-get update
sudo apt-get install nemo

In a terminal. The nemo app will them be accessible from the dash.


Mendeley Desktop 1.19.2 doesn't launch in Ubuntu 18.04.1

Ubuntu 18.04 does not work with 32 bit anymore. So you have the 64 bit version and you need to chose the 64 bit-version of mendeley


How to permenantly disable (not uninstall) Network Manager on Ubuntu 16.04 LTS?

Try this:

To permenantly disable Network Manager:

Open a terminal,Press Ctrl+Alt+T

Run it:

exec sudo -i
systemctl stop NetworkManager.service
systemctl disable NetworkManager.service
mv /lib/systemd/system/NetworkManager.service NetworkManager.service.res

To renable Network Manager:

Open a terminal,Press Ctrl+Alt+T

Run it:

exec sudo -i
mv /lib/systemd/system/NetworkManager.service.res  NetworkManager.service
systemctl enable NetworkManager.service
systemctl start NetworkManager.service


After upgrade to kernel 3.16.0-30-generic I cannot use the keyboard

Some possibilities:
nomodeset lurking in the grub config
http://ubuntuforums.org/showthread.php?t=2264430
Hit Esc in the prompt
Ubuntu 14.10 boot takes ESC to give encryption passphrase prompt

I'm also seeking an answer, since I'm struggling with the same problem. Fresh install of 14.10, get the encryption prompt and nothing works.

I resolved this on my own machine just now, by removing the "quiet" and "splash" options from the kernel and using the same "ro" option used by the recovery mode. Otherwise, when running not in recovery mode, I get stuck at loading initramfs.

To do this, I edited /etc/default/grub to set the variable GRUB_CMDLINE_LINUX_DEFAULT to "ro" from "quiet splash"


Questions About Kernel Upgrade and Computer Maintenance

After your first uname -r it listed 4.4.0-53 as the kernel version you last booted with.

When you did sudo apt upgrade it offered to update your disk with newer kernel 4.4.0-57 but you must select Y to upgrade it on disk. You did not say if you did this or not.

When you typed uname -r a second time it still shows 4.4.0-53 as the kernel you booted with because you haven't rebooted yet.

Anyways... Do the upgrade and select Y and then reboot to get the newest kernel booted into RAM and virtual directories /proc, /sys, etc.


Installing the extension package you linked would not be a culprit.  Running that will install the or reinstall the extensions.

Fix your broken packages by running the commands in this answer.

You might have to loop through them more than once.  Each loop would provide cleanup residue from the previous loop.  You after looping twice you shouldn't get any errors or warning.


Offline programs like Mozilla Seamonkey for Ubuntu

place your html files in /var/www/ go to your local ip and use the file name to specify what file you want to test. Use any web browser you want.

Some web servers you should take a look at.

sudo apt-get install lamp
sudo apt-get install apache2


Automatically ban IPs that request certain pages

First try this on a machine you have physical access to.

IP Tables

First, let's figure out the IP Tables rules to block an IP Address. For detailed instructions, check out this guide.Let's drop all incoming connections from a particular IP:

iptables -A INPUT -s A.B.C.D -j DROP

After this, restart iptables as regular. Try out this command to check if it works fine for you, get familiar with the syntax and then proceed further.

Bash Script

Let's create a Bash Script to block an IP. It would look something like this (warning: You might need to play with user permissions and sudo to get it to work). Create a new file, say, blockip.sh.

#! /usr/bin/env bash
iptables -A INPUT -s $1 -d DROP
<other stuff you want to do when you block an IP>
<note: the IP address is in variable $1>

Run chmod +x blockip.sh to make the script executable. Now you can run it as /path/to/file/blockip.sh 1.2.3.4.

Sudo Permissions

If your script needs to have root user permissions, you need to configure sudo to provide you passwordless access. Referring from this Stack Overflow Question, run sudo visudo and add the following line:

nobody ALL = NOPASSWD: /your/script

Save the file and exit. As a security warning, make sure that only you can modify the script file or else, someone can potentially run harmful code as root user by modifying the script.

PHP Code

Run this little gem of code whenever you want to block someone.

exec("sudo /path/to/file/blockip.sh ".$_SERVER['REMOTE_ADDR']);

Conclusion

First, test this code on a machine you have physical access to. Also, be aware that multiple users behind a LAN would share the same external IP and blocking one of them would result in blocking all of them. Be careful. Upvote if the answer helped you.


E: Impossible de trouver le paquet minicom

Here is How do I restore the default repositories.

After that do:

sudo apt-get update

And install Minicom by tuping:

sudo apt-get install minicom


Keyboard shortcuts fails after upgrade to 17.04 (layout switcher)

It is known ugly bug - see launchpad bug 1245473.

I'm writing this from Ubuntu 16.04.3 LTS with MATE DE. It does not have this problem.
I'm using Ctrl+Shift layout switcher for English and Russian languages.

But MATE on Ubuntu 17.10 has this problem - see other launchpad bug 1720364.

My complete position is written in comment 528 for bug 1218322 at launchpad.


I blogged about the solution which worked for me, here

sudo xrandr --newmode "1600x900_60.00"  118.25  1600 1696 1856 2112  900 903 908 934 -hsync +vsync
sudo xrandr --addmode VBOX0 "1600x900_60.00"
sudo xrandr --output VBOX0 --mode "1600x900_60.00"

First command creates a new mode with resolution 1600x900
Second command makes it available for use, with display (in this case VBOX0)
Third command selects the newly added mode as the display resolution for the specified display

To change this to any custom resolution, just replace 1600 with the width you want and 900 with the height you want.


You're correct. Bad sectors happen on hard disks. Your error message could mean impending disk failure due to a head crash. Since we don't know how many bad sectors you started with, we don't know if 1592 means 1592 new bad sectors, or just 1 new bad sector.

First, I'd start the Disks application, go to the "hamburger" icon and select SMART Data & Tests. Review the data, and run the tests.

Second, I'd install gsmartcontrol... this will help with prewarnings... and another way to monitor the SMART data...

sudo apt-get update
sudo apt-get install gsmartcontrol

Keep monitoring the disk and the SMART data and keep a keen eye on the bad block count. Perform regular backups.


I've Installed Inkscape via "apt-get install" in LXTerminal but I cant find where is it?

If you installed with the Terminal aka sudo apt-get install inkscape, the program is located in the LXDE Menu>Graphics category.


Apache server ends up "blacklinsting" browsers

try to find system logs and check if some info about the errors.

The "faulty screens" are consulting some Database, can be the workload to heavy and provoke a timeout?


shell to print modification date of all directories name match pattern

You can use find itself to print the whole thing:

for pattern
do
    find . -type d -name "*$pattern*" -printf 'The folder %P was modified on %t\n'
done

for pattern; do ... done loops over all the arguments, with the pattern variable set to each argument in turn.

With find, %P and %t give the path to the file and modification time in -printf.


All Ubuntu releases as of July 2017

To install the Skype for Linux application (version 8+):

  Download the Deb package for Skype for Linux with your favourite web browser or HTTP client.

  For a terminal-based solution use:

wget https://repo.skype.com/latest/skypeforlinux-64.deb

  Install the Deb package with your favourite package manager, e. g. Software Center or GDebi.

  For a terminal-based solution or to debug the package installation use:

sudo apt install ./skypeforlinux-64.deb

  You’re done! When you installed the package it automatically added a repository […] to keep your installation of Skype up to date via Ubuntu's package update process.

(source)

The new Skype application works only on 64-bit (amd64) installations of Ubuntu.


Howto enable spellchecking in Canadian English (incl in LibreOffice) for all users / system-wide

Canadian spell-checking is available.

sudo apt-get install hunspell-en-ca


Where can you download 32 bit edition of Google Chrome for Ubuntu OS?

Google has discontinued chrome for 32 bit machines running Ubuntu. If you go to the chrome download page and hit the download button you'll see that it only offers 64-bit options.

A simple Google search will also pull up a bunch of articles about it--here's a couple I found:
http://www.omgubuntu.co.uk/2016/01/google-chrome-linux-32-bit-discontinued
http://betanews.com/2015/11/30/google-killing-chrome-for-32-bit-linux/


Kodi is a GUI media player
No out-of-the-box Headless Kodi exists
BUT some users have worked on an headless Docker image of Kodi
Another one have worked on a fake Xorg display with XRPA

You can find all information about those on the Kodi Forum


Why the difference between Samba sharing inside Home folder and outside (eg: mounted device)

You have to force the incoming connection to look like yourself by adding the following line in /etc/samba/smb.conf, in the last "Share" section (for every external source separately):

force user = (your user name)

Solution is on this link


dosfsck seems to hang after bad cluster message

what to do?

Generally I would expect a hardware problem when a filesystem check locks up.

The only advice I can give is to try to repair it using Windows. Dos tools will be almost 100% compatible but there is never a guarantee. You might just have ran into a bug.

Besides that: open a 2nd terminal and see if any of the logs in /var/log/ is being written. If so there might be a notice there that explains there is a problem. If so add that to the question.

The other option is to throw it into the bin.


How can I lock the screen in Xubuntu 14.04?

Right click on the panel, click on panel --> Add New Items, and click on Action Buttons, and then click on add.

After you click add you will notice that your user name appears in the upper right hand corner of the screen

Click on your name on the upper right corner of the screen

and then click on lock screen


How can I safely remove desktop environments from Ubuntu Studio login screen?

As far as I know the desktop environments you mentioned has nothing in common except some gnome software like gnome-terminal and gnome-system-monitor which is used by Cinnamon.So for example I think it's completely safe to remove Xfce4 and its window manager and also some unneeded gnome software like gnome-shell and gnome-session :
sudo apt-get remove xfce4* xfwm4* gnome-shell* gnome-session*

Note that gnome-session* includes gnome-session-wayland too,so your gnome on wayland(aka Ubuntu on Wayland) would get deleted too.The same with gnome-shell*.
Another option is to delete the package ubuntu-gnome-desktop but it might result in removing some programs that you might want , for instance libre-office or gnome-mines, etc.
I think those are enough to delete the unnecessary packages and DEs and at the same time to prevent your system from breaking.But it might not be a 100% cleanup.


It should be in below directory:

/usr/share/applications/mimeapps.list

If its not be exists, you can create it, and put that line into this file:

sudo nano /usr/share/applications/mimeapps.list

Also you can create this file in your home directory:

nano ~/.local/share/applications/mimeapps.list

And put this line into that file:

application/vnd.nokia.qt.qmakeprofile=qtcreator.desktop

For example my mimeapps.list file content is:

$ cat /usr/share/applications/mimeapps.list
[Default Applications]
application/wps-office.et=/usr/share//applications/wps-office-et.desktop
application/wps-office.ett=/usr/share//applications/wps-office-et.desktop
application/wps-office.xls=/usr/share//applications/wps-office-et.desktop
application/wps-office.xlt=/usr/share//applications/wps-office-et.desktop
application/vnd.ms-excel=/usr/share//applications/wps-office-et.desktop
application/msexcel=/usr/share//applications/wps-office-et.desktop
application/wps-office.xlsx=/usr/share//applications/wps-office-et.desktop
application/wps-office.xltx=/usr/share//applications/wps-office-et.desktop
vnd.ms-excel.sheet.macroenabled.12=/usr/share//applications/wps-office-et.desktop
vnd.ms-excel.template.macroenabled.12=/usr/share//applications/wps-office-et.desktop
application/wps-office.dps=/usr/share//applications/wps-office-wpp.desktop
application/wps-office.dpt=/usr/share//applications/wps-office-wpp.desktop
application/wps-office.ppt=/usr/share//applications/wps-office-wpp.desktop
application/wps-office.pot=/usr/share//applications/wps-office-wpp.desktop
application/vnd.ms-powerpoint=/usr/share//applications/wps-office-wpp.desktop
application/vnd.mspowerpoint=/usr/share//applications/wps-office-wpp.desktop
application/powerpoint=/usr/share//applications/wps-office-wpp.desktop
application/wps-office.pptx=/usr/share//applications/wps-office-wpp.desktop
application/wps-office.potx=/usr/share//applications/wps-office-wpp.desktop
vnd.ms-powerpoint.presentation.macroenabled.12=/usr/share//applications/wps-office-wpp.desktop
vnd.ms-powerpoint.template.macroenabled.12=/usr/share//applications/wps-office-wpp.desktop
application/wps-office.wps=/usr/share//applications/wps-office-wps.desktop
application/wps-office.wpt=/usr/share//applications/wps-office-wps.desktop
application/wps-office.doc=/usr/share//applications/wps-office-wps.desktop
application/wps-office.dot=/usr/share//applications/wps-office-wps.desktop
application/vnd.ms-word=/usr/share//applications/wps-office-wps.desktop
application/msword=/usr/share//applications/wps-office-wps.desktop
application/msword-template=/usr/share//applications/wps-office-wps.desktop
wps-office-doc.png=/usr/share//applications/wps-office-wps.desktop
wps-office-dot.png=/usr/share//applications/wps-office-wps.desktop

For more information about MIME type default applications, please look at this link in Arch linux Wiki.


How to find the executable file of an app if 'whereis' is not showing it?

You can use apt-file search <package-name> or dpkg -S <package-name>, where <package-name> is the package you want to search.

Note that these commands will output many results. To find the required package use grep:

apt-file search package | grep -E "(bin/)?package$"

OR

dpkg -S package | grep -E "(bin/)?package$"

This searches the lines whose last word is package and may or may not be preceded by bin/, for example it will result both /usr/bin/package and /usr/anydirectory/package.


How to have double click on title bar maximize/restore behavior?

Need to verify in two places,

System → Preferences → Windows
Change the Titlebar action to Maximize.

System → Preferences → Emerald Theme Manager → Emerald Settings tab
Change Titlebar Double-Click Action to Maximize/Restore.


Is it possible to give two IP addresses for the same host name?

It's not really possible as in this specific example.  Your hosts file essentially forms part of your system's ability to map a hostname into an IP address.  So when your system wants to know the IP address of "example", it'll get a single IP address in reply.  The hosts file allows no way of distinguishing different "record types" for its resolution.  So for hostname to IP address mapping, you only get one IP address per hostname (but multiple hostnames could resolve to the same IP address, which is the opposite).

Depending on what you're doing, might it be possible to use an external DNS service like dyndns.org to map a constant hostname, that will work on either network, to your IP address?


can not authenticate libopenexr6 in update manager

Open your terminal and type this:

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

to get updates .

Regarding to your issue, open your update manager and select settings option. In settings window at other software option make sure that you have selected all PPA's. Then try again.


Setting up static ip with wireless N USB adapter (TL-WN723N) ubuntu 16.04.2

Found the solution!
https://www.thefanclub.co.za/how-to/how-add-wireless-lan-adaptor-static-ip-ubuntu-auto-connects-startup.
Just follow the guide in the link.


How do I remove all the ufw chains from iptables?

This two liner run as root will quickly find all the names and run them through a for loop that runs iptables -F to flush references to the chain then iptables -X to delete them.

for ufw in `iptables -L |grep ufw|awk '{ print $2 }'`; do iptables -F $ufw; done
for ufw in `iptables -L |grep ufw|awk '{ print $2 }'`; do iptables -X $ufw; done


I suggest qdvdauthor or dvdrip as gui based. But i HIGHLY suggest using console tools like ffmpeg, mencoder and similars. They do a fast, excellent job.

You can also MAKE an iso of a vcd with acetoneiso, brasero (Which comes by default in Ubuntu) or k3b (Which comes by default in Kubuntu) and then burn it like dvd with something like devede.

Remember that you can not make a video with higher quality than what it has in the beginning. In your case you cant make a vcd quality movie have a dvd quality. It is like a dvd quaility trying to have a blue-ray quality.

All the tools i suggested can be found in the ubuntu software center or synaptic.

If you are going to use all the tools for that then you should first make the vcd to iso and then test it by viewing it with vlc. If all is good then burn it with devede which will make it into dvd format (With an optional menu) and you can just burn it and watch it in your media player.

Us the following in console to have them all installed:

sudo apt-get install vlc devede acetoneiso ubuntu-restricted-extras mencoder ffmpeg

This should have you ready to transform anything to dvd.

Remember:

Make the ISO from the source. In your case a VCD. You can use acetoneiso or brasero for it.
OPEN the iso with VLC to watch it and see how it all came out. If good then open with DEVEDE


How to boot load the kernel using EFI stub (efistub) loader with secure boot?

The problem you're encountering is a result of the fact that Ubuntu's kernels (the ones with filenames that end in .efi.signed) are signed by Canonical's Secure Boot key. This key is not included in most computers' firmware, and so will be rejected by most computers' Secure Boot subsystems. (There are a few exceptions to this rule. I have an ASUS P8-H77I motherboard, for instance, that came with Canonical's public key embedded as standard. If yours were so configured you wouldn't be having this problem, though.)

Broadly speaking, you have three options:

Take full control of Secure Boot -- You can take full control of Secure Boot and install whatever Secure Boot keys you like. If you add Canonical's key, you'll be able to launch Ubuntu's signed kernels directly. This process is tedious, though. For details on how to do it, see my Web page on the subject. In brief, you'll need to generate your own keys, delete your computer's current key set, add your own keys, add Canonical's key, and optionally add any other keys you might want to use (like Microsoft's keys). There are several ways to do this, some of which rely on the firmware's own user interface, and therefore can't be described with 100% accuracy in a generic way.
Use Shim -- You can use the shimx64.efi program that ships with Ubuntu to launch your kernel. To do this, you would put shimx64.efi in the same directory as the (renamed) kernel and add shimx64.efi to the boot list (via efibootmgr) rather than the kernel. One extra trick is that you'll have to pass the kernel's filename and options to shimx64.efi via appropriate efibootmgr options. This would be similar to the efibootmgr -c... command in step #3 of the answer you referenced, but the program file would be shimx64.efi and the kernel filename would become an option passed via -u. Note that not all versions of shimx64.efi support passing options in this way. I don't recall exactly when this feature was added, but you should be OK with a recent version. Note that I've never attempted to do exactly this myself, so I can't provide you with step-by-step instructions; you'll probably have to experiment to figure out the details yourself. This also means that there's a chance it won't work, although in theory it should work.
Use a more conventional setup -- IMHO, launching the kernel directly, as you're attempting, is not a good approach, even without Secure Boot in the picture. Although using GRUB, rEFind, or some other boot loader or boot manager is technically a complication of the boot process, these boot programs provide tools for managing the boot process that simplify actual setup. Thus, it's better to use one of these tools, IMHO. If you have a specific gripe with GRUB, you might want to share that; it's conceivable that another boot program will address your issue. If you're just doing this as a learning exercise, though, launching the kernel directly has merit. You'll certainly learn something about the EFI boot process and, in your case, Secure Boot, by getting it working.

If you want an easy solution, using a conventional boot loader or boot manager is the way to go. If you want to learn the most, you might want to look into taking full control of Secure Boot -- but be aware that there are a lot of pitfalls along that path, so it's likely to take a while, even with the help of a guide like the one I wrote and referenced earlier. Using Shim is a sort of middle ground -- it's easier to set up than the full-control approach, but you'll learn less doing it this way.


This is probably due to the fact that you are running ntp in a unprivileged container. OpenVZ is another project for containers, but like the others it share the same kernel between the host and the guests. And as the kernel maintain the time, it would be not acceptable for a VPS host that one container can change the kernel time, because that would impact all other container.

So there is not solution to your problem. If you find that the time reported inside your OpenVZ container is incorrect, you need to open a support ticket with your VPS host provider. They have to install ntpd on their host and make sure it is correctly synchronised.


There are many different Dell Optiplex 760 machines with different CPUs. If you have one with a 64-bit processor, just add RAM and you can run full-up Ubuntu. To find what you have, enter your service tag at the Dell PC Support Site, or open a terminal in Ubuntu 16.04 and run lscpu | grep Architecture

Without a 64-bit processor you will be limited in your choices when it comes to running full-up Ubuntu with the heavy GNOME3 desktop. However, Ubuntu also offers flavors with less demanding desktop environments which sill still run Ubuntu apps.

32-bit flavors of 18.04 include:

Lubuntu
Ubuntu Budgie
Kubuntu and
Ubuntu MATE.


According to man pages of find perm +mode is deprecated

-perm +mode
              This is no longer supported (and has been deprecated since 2005).  Use -perm /mode instead.

You can try:-

find / -perm /6000 -type f


How do I install a new language pack for Tesseract on 16.04

Just install the necessary ocr language using this:
sudo apt-get install tesseract-ocr-[lang]

Where [lang] can be
all

OR
afr
amh
ara
asm
aze
aze-cyrl
bel
ben
bod
bos
bul
cat
ceb
ces
chi-sim
chi-tra
chr
cym
dan
dan-frak
deu
deu-frak
dev
dzo
ell
eng
enm
epo
est
eus
fas
fin
fra
frk
frm
gle
gle-uncial
glg
grc
guj
hat
heb
hin
hrv
hun
iku
ind
isl
ita
ita-old
jav
jpn
kan
kat
kat-old
kaz
khm
kir
kor
kur
lao
lat
lav
lit
mal
mar
mkd
mlt
msa
mya
nep
nld
nor
ori
pan
pol
por
pus
ron
rus
san
sin
slk
slk-frak
slv
spa
spa-old
sqi
srp
srp-latn
swa
swe
syr
tam
tel
tgk
tgl
tha
tir
tur
uig
ukr
urd
uzb
uzb-cyrl
vie
yid

This means if you want to, say, install the Norwegian version you can run:
sudo apt-get install tesseract-ocr-nor


How do I install ubuntu on a Asus F55A with freedos

Create a bootable ubuntu usb drive using unetbootin software on the notebook.How to install and run UNetbootin?
Dualboot windows and ubuntu How can I dual boot Windows and Ubuntu?


Black screen after 15.10 upgrade, not even getting into tty1 anymore

Completely reinstall the NVIDIA drivers! I assume that you have a GPU newer than GEFORCE 400.

When the GRUB boot menu appears : Highlight the Ubuntu menu entry and  press the E key.
Add the nouveau.modeset=0 parameter to the end of the linux line ... Then press F10 to boot.

When the login screen appears press Ctrl+Alt+F1.

Enter your user name and password. Now uninstall every NVIDIA related software by executing:

sudo apt-get install ppa-purge
sudo ppa-purge ppa:xorg-edgers/ppa
sudo apt-get update
sudo apt-get purge nvidia*
sudo reboot

When the GRUB boot menu appears : Highlight the Ubuntu menu entry and  press the E key.
Add the nouveau.modeset=0 parameter to the end of the linux line ... Then press F10 to boot.

When the login screen appears press Ctrl+Alt+F1.

Enter your user name and password. Now reinstall the NVIDIA drivers by executing:

sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update
sudo apt-get install nvidia-355 nvidia-prime
sudo reboot

Note:

As you did not provide any information about your NVIDIA graphics card check drivers versions.
Replace 355 with the latest stable main version number supporting your NVIDIA GEFORCE GPU.
If you ever have had bumblebee installed before to switch between graphics - also remove this.


Ubuntu offers several ways to remove an application. For all further explanations I assume that you installed some Ubuntu package. So the explanation is not valid if you installed software via ./configure && make && make install or used some kind of app specific setup wizard.
Software-Center
Ubuntus Software-Center (Applications --> Software-Center) lists software which is currently installed on your computer. You can use the search box to look for a specific application. Click on the application you wish to remove and click on the Remove-button.
Synaptic
Another way to remove software is by using Synaptic. Click on System -> Administration -> Synaptic. A new window open and you can enter some search term into the box. So you will narrow down the list of software. After you found the software to remove right-click on the package and select Mark for Removal. Then apply the changes. Synaptic will show you a window with the changes it wants to make and if you apply the software will be removed.
Aptitude
Aptitude is a text-mode software. You will need to open a terminal and enter sudo aptitude. Aptitude shows you a textual interface. You can search for your software by typing a slash (/) and entering some part of the name. If the software doesn't show the software in the first place (some packages have similar names) click n. If you find the package you want to remove enter -. After you found all your software enter g. Aptitude will show you all software it wants to remove. If all is correct enter g again and the software will be removed.
Aptitude can also be used via commandline. If you know the exact name of the software type:
aptitude remove packagename

You can also use aptitude purge packagename. Aptitude will then remove anything which is related to the software (config files, database files etc.)
apt-get
apt-get is a full command line program. If you want to remove software enter:
apt-get remove packagename

You can also use purge as in aptitude.


Problems printing to Xerox 6027 from Gnome Ubuntu

After testing the printer on a Windows computer and another Ubuntu machine it seems the problem is with the router and not the computers or the printer.


Enabling notification sound for all stuff in GNOME

I wrote a small background program to solve this problem for myself:

https://github.com/dbazile/gaudible

If you're handy with Python, you should be able to copy and extend it to cover all of the notification categories you're interested in.


Why Won't WUBI Start On Windows XP (32-Bit)

Move the Wubi.exe in the same folder in which the Ubuntu .iso file is.
 Also make sure that you don't have any other .iso archives in that folder.


Will Rhythmbox automatically add missing album information when I put a new album in my music folder?

No, it wont, by default. I am not aware of any plugin to do the task either. The plugin that is with Rhythmbox, might get you the covers for it. If you want to tag your songs, I recommend you use MusicBrainz Picard. Open a terminal from Menu > Accessories > Terminal and type the following:

sudo apt-get install picard

To get started with tagging, read the manual (with screenshots) given at the Picard website.


General way to monitor ALL memory usages

You might try smem for at least a goodly portion of what you are looking for.

It's available in the Universe repository and can be installed with sudo apt-get install smem

There are a number of useful switches that are covered on the man page man smem

Some examples are as follows:
Note I'm using the -t switch for totals in all examples for brevity. you can leave it out if you want more verbose output.

PSS is the interesting column in these examples as it takes shared memory into account.
Unlike RSS it's meaningful to add it up.

System Wide

me@zippy-64bit:~$ smem -tw
Area                           Used      Cache   Noncache
firmware/hardware                 0          0          0
kernel image                      0          0          0
kernel dynamic memory        989656     860076     129580
userspace memory             936032     180020     756012
free memory                 5692716    5692716          0
----------------------------------------------------------
                            7618404    6732812     885592

By user

me@zippy-64bit:~$ smem -tu
User     Count     Swap      USS      PSS      RSS
me          67        0   861452   898915  1245592
---------------------------------------------------
            67        0   861452   898915  1245592

Also of note are smemcap for capture of data for future analysis with smem and smemstat which reports the physical memory usage taking into consideration shared memory. The tool can either report a current snapshot of memory usage or periodically dump out any changes in memory.

There's also a list at the bottom of the page of similar packages.

Sources:

Correctly determining memory usage in Linux - Unix & Linux
man smem
Ubuntu – Details of package smem in xenial
Smemstat - shared memory statistics

Alternative 1: You might also consider parsing the output of cat /proc/meminfo or if you want it by the page less /proc/meminfo

Much of the information here is used by free, top and ps commands. In fact, the output of the free command is similar in appearance to the contents and structure of /proc/meminfo. But by looking directly at /proc/meminfo, many more details are revealed including :

$ cat /proc/meminfo | grep "Slab"
Slab:             267680 kB

Alternative Source: https://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-proc-topfiles.html

Alternative 2: If you are truly committed to a better parsing of kernel RAM you might roll your own kstat. While kstat appears to be a Solaris only command. the link above will take you to sources for for an open source attempt at kstat that was last modified in 2013 (as of this edit.) A clever C programmer might be able to modify the code for their specific purpose.

Alternative 2 source:


How can I debug/monitor Emacs to find out why it's using so much memory?

Perhaps the package emacs-snapshot-dbg might be of interest?

"This package contains the debugging symbols useful for debugging Emacs."


I found this : https://wiki.ubuntu.com/Multitouch
Problem is that the swipe and pinch stuff is only about the trackpad.
Mine does not support it yet, the driver seems not ok.
That link shows what gestures work and hints to some further options.


How do I update skype through snap in ubuntu?

If you have installed the Skype snap package, you can update it by running the following command in Terminal

snap refresh skype

If you have installed Skype deb package downloaded from their official website, then run

sudo apt-get install skypeforlinux


Ethernet not working on ubuntu 14.04 LTS

Follow the steps here:

Download e1000e here
Building and installation

Move the base driver tar file to the directory of your choice. For example, use /home/username/e1000e or /usr/local/src/e1000e
Untar/unzip the archive, where  is the version number for the driver tar file:
Change to the driver src directory, where  is the version number for the driver tar:

cd e1000e-<x.x.x>/src/
tar zxf e1000e-<x.x.x>.tar.gz

Compile the driver module:

make install

The binary will be installed as:

/lib/modules/<KERNEL VERSION>/kernel/drivers/net/e1000e/e1000e.[k]o

The install location listed above is the default location. This may differ for various Linux distributions.
Load the module using either the insmod or modprobe command:

modprobe e1000e insmod e1000e

Note that for 2.6 kernels the insmod command can be used if the full path to the driver module is specified. For example:

insmod /lib/modules/<KERNEL VERSION>/kernel/drivers/net/e1000e/e1000e.ko

With 2.6 based kernels also make sure that older e1000e drivers are removed from the kernel, before loading the new module:

rmmod e1000e; modprobe e1000e

Assign an IP address to the interface by entering the following, where  is the interface number:

ifconfig eth<x> <IP_address>

Verify that the interface works. Enter the following, where  is the IP address for another machine on the same subnet as the interface that is being tested:

ping <IP_address>

Note

Some systems have trouble supporting MSI and/or MSI-X interrupts. If you believe your system needs to disable this style of interrupt, the driver can be built and installed with the command:

# make CFLAGS_EXTRA=-DDISABLE_PCI_MSI install

Source


Latest upgrade of Ubuntu 18.04 leads to automatic sleep and wake servers

Launch a bug report, it seems like it bug. however try Unity Tweak Tool it may have some power settings within it. if not disable sleep mode.

How do I disable my system from going to sleep?


https of subdomain redirects to main domain - certbot on nginx

This is entirely the fault of the NGINX configuration, and it is behaving As Configured by certbot / yourself.

When an NGINX server section listens on a port, if it is the only service listening on that port it will become the default server block to match on that port.  This is By Design.

You will need a separate section in your configuration for your subdomain with a valid HTTPS configuration and certificate on it to make requests to https://sub.example.com/ to go to the correct docroot.

Example configuration of this (except both server blocks serve HTTP and HTTPS without needing to expand the number of server configurations):

server {
    listen 80 default_server;
    listen 443 default_server;

    server_name example.com;

    ssl_certificate /etc/nginx/ssl/example.com.crt;
    ssl_certificate_key /etc/nginx/ssl/example.com.key;

    root /var/www/example.com;

    if ($scheme = http) {
        return 301 https://$server_name$request_uri;
    }

    # ... other config here
}

server {
    listen 80;
    listen 443 ssl;

    server_name sub.example.com;

    ssl_certificate /etc/nginx/ssl/sub.example.com.crt;
    ssl_certificate_key /etc/nginx/ssl/sub.example.com.key;

    root /var/www/sub.example.com;

    if ($scheme = http) {
        return 301 https://$server_name$request_uri;
    }

    # other configuration for site here

}

When you request https://sub.example.com, it matches the configuration for the second site on HTTP and HTTPS because both HTTP and HTTPS listeners are configured for that server block.  If you request https://foo.example.com however, it will fall back to the server with the default_server block for the 443 listener, which serves example.com and not the subdomain.

Essentially, you need to have a custom configuration that serves a certbot certificate for your subdomain on port 443 in order to work.  Unfortunately, you cannot use the certbot nginx installer to do this, and will need to configure certbot to use standalone/webroot mode for your certificates and then configure NGINX yourself by hand for the proper paths to SSL certificates (and the .well-known handshakes that go on as well).

Certbot config on how to use standalone / webroot mode is here:  https://certbot.eff.org/docs/using.html#webroot

You will need to utilize this method to configure two separate SSL docroots/domains per your nginx configuration and then configure your NGINX ssl_certificate paths to point at the Lets Encrypt paths on-disk.  (This process is too long to fit into a single answer, but if you wish I can create a chat room to walk you through the process)


I can't use Blender, Kdenlive and Shotcut in 20.04 LTS

For kdenlive had the same problem. I resolved it using the appimage from the official web site. Maybe you can do the same with blender and shortcut…

remove kdenlive
download appimage from the official website: wget https://files.kde.org/kdenlive/release/kdenlive-20.04.1b-x86_64.appimage -O ~/Downloads
install appimage library: sudo apt install libappimage0
add execution bit to the .appimage file: chmod +x ~/Downloads/kdenlive-20.04.1b-x86_64.appimage
execute the file ~/Downloads/kdenlive-20.04.1b-x86_64.appimage


Common Home folder for ubuntu 16.04.1 and 18.04.1

If you have a separate home partition(say /dev/sda3), you simply have to select it on installation time to mount on /home and not to format.
If you have not a separate partition you can do two things,

1: Mount the old installation disk on /ubuntu (not necessarily ubuntu) in new installation. Then link home directory inside it to /home.

ln -sf /ubuntu/home /home

OR

2: Make a separate home partition. Copy all old contents(there in /home/*) to it and mount it to /home in both of installation

here is a simple partition guilde https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/5/html/deployment_guide/s1-filesystem-ext4-create

Problem or not?
Generally, there would be no problem. It might be a problem if you would like different home configuration. For example if you would like to use "Powerline" on one and not on other. If you would change configuration files like .bashrc in one, the other will get same effects. So you would not enjoy separate home configurations(I don't think this, a problem)


How can I downgrade Python or use many versions?

You can always install different versions of Python, they will coexist happily, just make sure you do not override the standard location (i.e. choose a different installation root directory).

For general use, make sure the old ones are generally not in your PATH.

When you need to test you GAE development, add the path to the 2.5 version and to GAE root directory in front of your PATH and you are set. For this to be convenient, I have created a function (could be an alias) in my .bashrc to change my PATH variable. Works like a charm.

function add_path
{
  (echo $PATH | fgrep "$1" >/dev/null) || export PATH="$1:$PATH"
}

function gae
{
  GAE="(G)"
  add_path /usr/local/share/Python-2.5.5/
  add_path /usr/local/share/google_appengine/
}

Of course locations may differ in your system.

I use the GAE variable in my PS1 so that I know when I have used that function - and I have a visual reminder to tell me I am set for GAE (i.e. I use the old Python version).


man nanorc(5):

color fgcolor,bgcolor regex
For the currently defined syntax,
display all expressions matching the extended regular expression regex
with foreground color fgcolor and background color bgcolor, at least
one of which must be specified. Legal colors for foreground and
background color are: white, black, red, blue, green, yellow, magenta,
and cyan. You may use the prefix "bright" to force a stronger color
highlight for the foreground. If your terminal supports transparency,
not specifying a bgcolor tells nano to attempt to use a transparent
background.


How do I build Nautilus 3.70/3.80 from source?

I have resolved this problem by installing a package using apt-get.

sudo apt-get install libtracker-sparql-0.16-dev.

If this gives a further set of errors as in Is there any way to Install Latest Nautilus File Manager in Ubuntu 12.04 LTS, Then add the repository mentioned there and it solved the problem for me.


The solution was provided by lidex at the ubuntu forums:

open a terminal and type:

echo "options snd-hda-intel model=z71v position_fix=1" | sudo tee -a /etc/modprobe.d/alsa-base.conf

then reboot the computer.


How do I invoke or start an application from command line?

Press ALT+F2 and write the name of your application , then click on it :)


How to embedded terminal in desktop background?

This is simply a terminal window opened without borders and with a transparent background. You can archive this with urxvt or tilda term , for example, by configurating them to open in the middle of the screen.

The only thing I couldn't change was that the window showed in the window list bar.


Error trying to open VeraCrypt container, veracrypt::process::execute:108

I did

 sudo apt-get install dmsetup

according to this post. It started working after that.


You can find the solution on here.
This happens when running two accounts on the same machine. The following steps will help clean this up.

Press Alt-F2, type "seahorse", press "Enter"

Right-click on any "Ubuntu One" and "Desktopcouch" entries and select "Delete"

Press Alt-F2, type "gnome-terminal" or "terminal", press "Enter" and run:

u1sdtool -q; sudo rm -rf ~/.local/share/ubuntuone; u1sdtool -c;


Don't rely on the systemctl status of iptables to determine if it's up.  The service simply is a onetime service called at boot to run iptables-restore from /etc/iptables/rules.v4 and /etc/iptables/rules.v6.  It's not a persistent services.
You would check via sudo iptables -xvnL or similar commands to make sure that iptables rules have populated.


Experiencing tears/glitches in my screen on Ubuntu 16.04 and 17.04

Install Compizconfig Settings Manager

sudo apt install compizconfig-settings-manager

In there, go to:

General -> Composite -> Unredirect Match

and add Google-chrome to the list. Be careful with CCSM - it's very powerful.


Where is the file used by file(1) and libmagic to determine mime types?

You were almost there; it's in /usr/share/file/magic.mgc:

$ file /usr/share/file/magic.mgc
/usr/share/file/magic.mgc: magic binary file for file(1) cmd (version 7) (little endian)

As a slight aside, I actually found this just by looking around a bit, but you can prove it's actually using that file via strace:

$ strace file /
<snip lots of output>
open("/usr/share/misc/magic.mgc", O_RDONLY) = 3
<snip a bit more output>

/usr/share/misc/magic.mgc is just yet another symlink. I guess the manpage is out of date.


Only one of my two network cards is working

I made a possible running example based on the basic implementation (of Split access) taken from here.

Create two additional routing tables, say T1 and T2.

ip route add 192.168.3.0/24 dev eth0 src 192.168.3.5 table T1
ip route add default via 192.168.3.0/24 table T1
ip route add 192.168.5.0/24 dev eth1 src 192.168.5.10 table T2
ip route add default via 192.168.5.0/24 table T2

Set up the main routing table:

ip route add 192.168.3.0/24 dev eth0 src 192.168.3.5
ip route add 192.168.5.0/24 dev eth1 src 192.168.5.10

Add your preference for default route:

ip route add default via 192.168.3.5

Set up the routing rules, choose what routing table to route with.

ip rule add from 192.168.3.5 table T1
ip rule add from 192.168.5.10 table T2

More info here.


How do I revert to a previous version of iwlwifi?

Unfortunately, I do not see iwlwifi in any version of Ubuntu that I'm using (maybe you could clarify which brand of Ubuntu you are using, which package versions you have installed, where did you get them from), therefore my answer will be generic.

In general, you can force the installation of a particular version like that:

sudo apt-get install package=version

You can find what versions are available by

apt-cache policy package

Also, you can locate the particular deb package you need, download it and downgrade it manually:

sudo dpkg -i --force-downgrade packagename.deb

You can then make sure that the package will not be upgraded by pinning it, either in the GUI of the synaptic package manager, or through command line:

sudo echo package hold | dpkg --set-selections

Unfortunately, if the package is not available in a particular version, you need to install it from sources, following the instructions on the website of the package originator.


Why does accessing /localhost give "File not found" error?

The address is not correct.

It should be http://localhost, not /localhost only.


cooja compiling error: msp430/bin/ld: cannot find -lc

If you chose the mote type as sky mote this might happen. Try to open this same file as cooja mote and compile, it still might work...


With the script below, you can set the screen's brightness from 0.1 to 1.0, in 9 steps, on any system that "obeys" xrandr.

Just run it with either the argument "up" or "down" to increase/decrease the current brightness one step.

The script

#!/usr/bin/env python3
import subprocess
import sys

arg = sys.argv[1]

# get the data on screens and current brightness, parsed from xrandr --verbose
current = [l.split() for l in subprocess.check_output(["xrandr", "--verbose"]).decode("utf-8").splitlines()]
# find the name(s) of the screen(s)
screens = [l[l.index("connected")-1] for l in current if "connected" in l]
# find the current brightness
currset = (round(float([l for l in current if "Brightness:" in l][0][1])*10))/10
# create a range of brightness settings (0.1 to 1.0)
sets = [n/10 for n in list(range(11))][1:]
# get the current brightness -step
step = len([n for n in sets if currset >= n])

if arg == "up":
    if currset < 1.0:
        # calculte the first value higher than the current brightness (rounded on 0.1)
        nextbright = (step+1)/10
if arg == "down":
    if currset > 0.1:
        # calculte the first value lower than the current brightness (rounded on 0.1)
        nextbright = (step-1)/10
try:
    for scr in screens:
        # set the new brightness
        subprocess.Popen(["xrandr", "--output", scr, "--brightness", str(nextbright)])
except NameError:
    pass

How to use

Copy the script into an empty file, save it as set_brightness.py
Test- run it by the commands:

python3 /path/to/set_brightness.py up

and

python3 /path/to/set_brightness.py down

If all works fine, add both commands to shortcut keys: choose: System Settings > "Keyboard" > "Shortcuts" > "Custom Shortcuts". Click the "+" and add both commands above to two different shortcut keys.

Explanation

The explanation on the code is pretty much in the script :)

Notes

As it is, the scripts sets the brightness equally for both the "main" and possible additional screen(s).


setting up a static IP address can be done through the GUI in Ubuntu 18.04.

Click your connection in top right menu bar.
Click your connection and click wired/wi-fi settings
Click the settings icon on the Wired/ Visible Networks section.
In addresses (try in ipv4 tab if not visible, select manual):

for address, you will need to enter the static IP address of your choice (eg. 192.168.0.3).
set netmask to 255.255.255.0.
set gateway to the IP address of your network gateway (most likely 192.168.0.1).

In DNS section, set this to your target devices current IP address (192.168.0.x), also can be found for the specific device by navigating to your gateway IP (192.168.0.1).
Next to DNS section, set the Automatic switch to off.
Click Apply.
Disconnect internet (sudo dhclient -r && sudo dhclient), connect again and navigate to gateway settings, your device should now have adopted the static IP (192.168.0.3) you set.


Setting up gvfsd to specify options when autolaunching gvfsd-fuse

The command smbnetfs is a great way to mount a samba share, while exposing plenty of configuration options.  In my case, since I was mounting a samba share, the options I was looking for (allow_other in my case) was exposed by this command smbnetfs.

This doesn't directly answer the question though, but it's possible that someone who finds this may be trying to do the same thing I was doing.  I will leave the question open in the hopes that someone will have figured out a way to directly do what is being asked (since a user may want this question solved for other reasons which this workaround does not solve).


Nautilus integration with google drive uses GVfs (abbreviation for GNOME Virtual file system). You can find GVfs mountpoints in:

/run/user/XXXX/gvfs

where XXXX is the UID of your user.

In my computer, google drive mountpoint is on /run/user/1000/gvfs/....

You can find the list of GVfs mounted filesystems running the following command:

gvfs-mount --list -i

If you want copy Google Drive files using terminal, you must use the gvfs-copy command instead cp.

As despicted here, there are specific gvfs-... type commands to process files in remote locations.


Most probably, that tag was overwritten by another rule.

Ubuntu 18.04 got updated rules .. Check using grep -r TAG in system rules folders, see man udev.
Custom rules file given low number .. Use udevadm test ... and udevadm trigger ... to verify which rules processed for that event.


In the file /etc/fstab on the line concerning the DVD/CD drive, in the forth space separated column, does it have the word 'user' or 'users'?  This may be part of a comma separated list.  Mine says:

/dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0

Also, are you logged in as a NON-root user at the GUI, before putting the disc in?

Note: 'user' and 'users' have some important differences, 'user', singular, is the one you want if you have any doubts.


CPU temperatures 90+ degrees Celsius on 2.5GHz and above

I have completely forgotten about this topic. Since the one to answer (Doug Smythies) which gave the right answer in the comments haven't made his comment as an answer, I will post it here:

The answer it to use a modified version of Thermald, made by Doug Smythies:

https://askubuntu.com/a/897856/838117

After using that script I experienced no overheat at all without sacrificing CPU freq.


I faced a similar problem with NUC7PJYH and an old LED TV. When I switch on the TV after powering up the NUC, I get the display alright.

So, instead of unplugging the HDMI, I would either change inputs - HDMI1>HDMI2>VGA etc. or restart the TV. I'm afraid I don't know a better fix.


In my question I had four locations containing a smb.conf file.  As stated, the  preferred folder is the /etc/samba folder.  I since deleted all of the other smb.conf files except for the backup file with no adverse effects.


Install RealtekRTL8723DE On Ubuntu 16.04LTSon an HP 15-BW005LA

The rtl8723de driver is in the extended branch of lwfinger's GitHub repo. The driver will make its way into the Linux kernel supplied with Ubuntu eventually, but if you need the driver now, you can build and install it yourself.

Step 1 is to compile the WiFi drivers in lwfinger's repo. Feel free to modify the number appended to the -j flag on make to change the number of parallel build jobs to suit the system, for instance, if memory is low.

$ git clone --branch extended https://github.com/lwfinger/rtlwifi_new.git >/dev/null 2>&1
$ cd rtlwifi_new && make -j8

Step 2 is to install the driver and reboot. After the restart, the driver should load automatically, but if it doesn't, it can be manually loaded with modprobe.

$ sudo make install
$ sudo reboot
[ system reboots ]
$ lsmod |grep --quiet rtl8723de || sudo modprobe rtl8723de


Is a Ubuntu backup accessible from Win 10?

I Assume you used Deja Dup, AKA Backup, the default backup app to make the backups in the external drive.
The Simple answer is NO! (Or Very Difficult)
There are two reasons for this:

External Hard Disk format. It is not clear if the external backup disk you used is formatted ext4 the default format used by Ubuntu, or NTFS, the usual format the external USB hard drives are formatted for Windows. If the USB drive is formatted ext4 then see the answer by K7AAY for possible ways to read ext4 formatted drives in Windows.
The compressed-incremental-multivolume-encrypted file format in which the backups are stored. Deja Dup (the default Backup program) does not simply copy the files from the laptop into the external drive. It stores them in in a compressed form so that every day only the changes made after the previous day's backup is stored (incremental). Large files are broken up to smaller chunks (multivolume) to keep the individual backup file sizes reasonable. Optionally, the backups can be encrypted with a password. The downside of this is it is not simple to restore the files without going through the app. There is no Windows version of Deja Dup I am aware of. Therefore even if the backup USB drive can be readable in Windows, restoring from these backups in a Windows computer will be very difficult.

Solution using Live Ubuntu USB
In this solution it does not matter if the backup USB drive was formatted ext4 or NTFS, as you will be booting from the Live Ubuntu USB to restore the backup.
I assume you do not have another computer with Ubuntu in it, but you have access to a Windows computer. To do this you will need:

Another computer running Windows that can boot from USB
Either sufficient disk space in this computer for a complete restore of all her files. Or a second empty USB drive to restore all her files. The empty USB drive should be formatted NTFS, so that Windows can read it later. Note, the backup files are compressed. The restored files may take more space than the backup files.
A Live Ubuntu USB, the same one used to install Ubuntu into a computer.

Note: This method does not allow selective file or folder restore. You will need a internal or external drive or partition to hold all the files and folders backed up.
Step 1: Boot Windows computer using the Live Ubuntu USB
Use the Try Ubuntu without Installing... option. You don't want to install Ubuntu here. Wait till the familiar Ubuntu desktop shows up.
Step 2: Plugin the Backup USB drive (and the second USB Drive to restore to, if needed)
Make sure you can read and write create folders etc. in the external drive. Create a Restore folder where all the files will go.
If you intend to restore to the internal hard drive of the computer, this is the time to mount the internal partition and create a restore folder where all the files and folders will get dumped. Again make sure the partition has sufficient free space for the full restore.
Step 3: Open Deja Dup
Search for Backups in the application launcher and open the app. Select Restore:

Step 4: Select the location of the Backups

Backup Location should be the default Local Folder. Select Choose Folder and navigate to the mounted backup USB drive. It may look something like /media/<username>/BackupDrive/<laptopname>/<username>/deja-dup. You will know you have reached the right folder if you see lots and lots of files names starting with "duplicity" and ending with ".gz".
Select Forward to go to the next step
Step 5: The Date of Backup
Select the date of the backup you want to restore, the default is the most recent:

Select Forward
Step 6: Restore to Where?
Here you need to change the default setting to Restore to specific folder

Click on the Restore folder (None) and navigate to the folder you created either in the internal drive or in the second USB drive.
Step 7: Click Restore

Read the Summary information and make sure they are correct. and hit Restore. Wait for a few hours/days/weeks, depending on the amount of data and the speed of the the USB drives involved.
Step 8: Restart and boot to Windows
Once Restore is complete, reboot the Live Ubuntu USB using the power button in the drop down menu from the top right corner. Unplug the Live USB when prompted and hit Enter. When Windows boots up, you should be able to find the restored files and folders in the location you put them.
Windows Solution (Not Fun or Easy!)
Deja Dup stores the backup files in multiple compressed files. These files may be for an occasional full backup and regular incremental backups. When large files are backed up, they are broken into smaller chunks and then compressed into separate backup files. Optionally, backups may be encrypted with a password. See Deja Dup site for more information.
I have not tried this method. It is based on Deja Dup documentation for restoring by hand under the worst case scenario.
You Will Need:
Windows does not come with all the tools needed such as gpg to decrypt the encrypted files.

Gpg4Win is the Windows version of gpg. You will need it only if the backups are encrypted.
tar is a file/folder compression program used by Deja Dup. Newer versions of Windows 10 includes this utility.
Be comfortable with the Windows command line.

The instructions below are from Deja Dup documentation.
Introduction
Deja Dup stores your data in small chunks called volumes. Some volumes belong to the periodic 'full' or fresh backups and others to the 'inc' or incremental backups. Starting with a full backup set of volumes at volume 1, you'll need to restore files volume by volume.
You have to look at a sample file name and understand its various parts:
duplicity-full.20110127T131352Z.vol1.difftar.gpg

duplicity is the name of the underlying program used by Deja Dup. All files must start with this prefix.
full or inc indicates the type of backup, full or incremental.
20110127 is the date of the backup, in this example, January 27, 2011.
131352 is the time of the backup in the standard format used by Linux.
vol1 is the volume number.
difftar is the suffix used by Deja Dup to indicate compressed data files.
gpg or gz indicates if the file is encrypted by gpg or compressed without encryption.
We will use this example file name for the instructions.
If Encrypted!
If you encrypted your backup, first you must decrypt the volume with gpg:
gpg --output duplicity-full.20110127T131352Z.vol1.difftar --decrypt duplicity-full.20110127T131352Z.vol1.difftar.gpg

This will give you a decrypted file duplicity-full.20110127T131352Z.vol1.difftar for the next step.
Decompress
If you just decrypted the file you will have duplicity-full.20110127T131352Z.vol1.difftar.
If your backups were not encrypted to begin with you will have a file duplicity-full.20110127T131352Z.vol1.difftar.gz.
Use the tar command to decompress the file:
tar xf duplicity-full.20110127T131352Z.vol1.difftar.gz

The decompression process will create the folders multivolume_snapshot and snapshot. After you decompress all the volumes, you will need to combine the chunks in the multivolume_snapshotfolder to recreate the large files.
Let's say you backed up a huge file /home/jane/essay.txt. You will have a folder called multivolume_snapshot/home/jane/essay.txt.
Use the following commands:
cd multivolume_snapshot/home/jane/essay.txt
type * > essay.txt

The first command changes the current directory to essay.txt.
The second command concatenates all the chunks into a single file called essay.txt inside the folder essay.txt. The original instructions used the linux cat command. Since cat is not in Windows, I substituted it with type. However, it may not work with files that are not in plain-text format.
Note: You may have to list the file names inside the folder in the order instead of *, to get the file back.
Restore Incremental Backup
Once you have restored the full backup you will have most of your files excepts the new files and the changes made after the full-backup was made.
Deja Dup documentation suggests use rdiff to stitch together files with incremental changes. Since this utility is not available in Windows, I am not sure if this can be done in Windows.
Hope this helps


Can we (easily) turn off the line wrapping of icons on the desktop?

Re.

Can this easily be change, tweaked, finetuned to get it in one line? Or in one line and shortened?

Ubuntu 18.04
To get the icon text, however long, to be restricted to one line and shortened, one can use dconf-editor which may need to be installed on your system if it isn't already present: sudo apt install dconf-editor should do it.
For this purpose, I created a file with just w repeated fifty times. This is what it looks like when I highlight it on the desktop:

and without highlighting it:

Now, by means of dconf-editor, one can change it to just one row:

I found I needed to log out and log back in to see:

Edit:
There's also a route to make the change using the command-line.
From your terminal, run:
gsettings list-recursively | grep ellipsis

One of the lines in a default, clean install would be:
org.gnome.nautilus.desktop text-ellipsis-limit 3

You can confirm that by running:
gsettings get org.gnome.nautilus.desktop text-ellipsis-limit

and the "default" response will be 3.
To change that to 1, run:
gsettings set org.gnome.nautilus.desktop text-ellipsis-limit 1

You may need to log out and log back in to see the effect.
Ubuntu Mate 18.04
Use:
gsettings set org.mate.caja.desktop text-ellipsis-limit 1

Again, log out and log back in.
Xubuntu 18.04
Here, the default is just one line, truncated. How many characters fit in on that line depends on the width of the characters involved:

However, it is possible to increase the number of characters per line as well as the number of lines by increasing the space allocated to each desktop icon obviously at the expense of reducing the number desktop icons that'll fit on your screen. See here. This route works in Xubuntu 18.04 and in Xubuntu 19.10 provided an appropriate gtk theme is used. Both Greybird and Numix, present in a default install, are fine.
Kubuntu 18.04
Kubuntu offers a graphical user interface to control the number of rows icon text occupies from one to ten.


Here is a script I found here https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-evdev/+bug/1246683, works fine for me:

#!/bin/bash

sudo apt-get install libevdev-dev libevdev2
sudo apt-get build-dep xserver-xorg-input-evdev xserver-xorg-input-synaptics

wget https://launchpad.net/ubuntu/+archive/primary/+files/xserver-xorg-input-evdev_2.9.0.orig.tar.gz
wget https://launchpad.net/ubuntu/+archive/primary/+files/xserver-xorg-input-evdev_2.9.0-1ubuntu1.diff.gz
wget https://launchpad.net/ubuntu/+archive/primary/+files/xserver-xorg-input-evdev_2.9.0-1ubuntu1.dsc

wget https://launchpad.net/ubuntu/+archive/primary/+files/xserver-xorg-input-synaptics_1.8.0.orig.tar.gz
wget https://launchpad.net/ubuntu/+archive/primary/+files/xserver-xorg-input-synaptics_1.8.0-1~exp2ubuntu2.diff.gz
wget https://launchpad.net/ubuntu/+archive/primary/+files/xserver-xorg-input-synaptics_1.8.0-1~exp2ubuntu2.dsc

dpkg-source -x --no-check xserver-xorg-input-evdev_2.9.0-1ubuntu1.dsc
dpkg-source -x --no-check xserver-xorg-input-synaptics_1.8.0-1~exp2ubuntu2.dsc

wget https://aur.archlinux.org/packages/xf/xf86-input-evdev-trackpoint/xf86-input-evdev-trackpoint.tar.gz

tar -xzf xf86-input-evdev-trackpoint.tar.gz

mv xf86-input-evdev-trackpoint arch
mv xserver-xorg-input-evdev-2.9.0 evdev
mv xserver-xorg-input-synaptics-1.8.0 synaptics

cp synaptics/src/{eventcomm.c,eventcomm.h,properties.c,synaptics.c,synapticsstr.h,synproto.c,synproto.h} evdev/src
cp synaptics/include/synaptics-properties.h evdev/src
cp arch/*.patch evdev

cd evdev
patch -p1 -i 0001-implement-trackpoint-wheel-emulation.patch
patch -p1 -i 0004-disable-clickpad_guess_clickfingers.patch
patch -p1 -i 0006-add-synatics-files-into-Makefile.am.patch

dpkg-buildpackage

cd ..
sudo dpkg -i xserver-xorg-input-evdev_*.deb
sudo apt-get remove xserver-xorg-input-synaptics

sudo mkdir /etc/X11/xorg.conf.d/
sudo cp arch/90-evdev-trackpoint.conf /etc/X11/xorg.conf.d

echo If everything was OK, than logout/reboot and enjoy fully working ThinkPad Trackpoint/ClickPad
echo If you want to deactivate touch area of ClickPad for pure TrackPoint usage
echo edit /etc/X11/xorg.conf.d/90-evdev-trackpoint.conf and change "0" to "1" at line
echo Option "AreaBottomEdge" "0"


In Software and Updates, if you disable all the other software repositories, this will allow you to receive updates.

Another way is to type in to Terminal

sudo do-release-upgrade

This should tell you what's available.


intel centrino wireless n 1030 wireless drop after reboot Ubuntu 14.04

From this answer: Reset WiFi you can power your WiFi off and on again after a reboot. This will simulate the physical power button cycling off and on which works for your laptop.


I had found a solution which is not the exact answer but an way around this problem. Actually in ubuntu 18.04  plug and play feature is (I guess) disabled; so the usb will show up in the ls command i.e.

ls /dev/sd* | grep sd

but will not be automatically mounted (except if if was present a boot time).

So solution is to mount is manually e.g. if the usb is detected at sdb1 then use this command

sudo mount /dev/sdb1 /mnt/usb

FYI: i am assuming that there is a usb folder in mnt folder


How do kernel updates differ from kernel upgrades?

The kernel version numbers are constructed as follows:

<base kernel version>-<ABI number>.<upload number>

Whenever there is an ABI change in the kernel the ABI number is incremented.  An ABI change can happen for example when: a structure changes, a function prototypes changes, or system calls are added. If there is a new build in which the ABI doesn't change, the upload number may only be incremented. This occurs sometimes when an important CVE needs to be fixed or the kernel is rebuilt due to a regression.

Source:

https://wiki.ubuntu.com/Kernel/FAQ#Kernel.2BAC8-FAQ.2BAC8-GeneralVersionMeaning.What_does_a_specific_Ubuntu_kernel_version_number_mean.3F


cannot configure or make install samtools 0.1.19

Really you do not need to compile this application by yourself.

It is packaged in all currently supported versions in universe pocket.
You can add this pocket with (if it is no enabled) the command:

sudo add-apt-repository universe

and then you can simply install it with:

sudo apt-get install samtools

If you really want to compile samtools, then you do not need to run ./configure script (as it does not exist), just use make:

cd ~/Downloads
wget https://vorboss.dl.sourceforge.net/project/samtools/samtools/0.1.19/samtools-0.1.19.tar.bz2
tar -xf samtools-0.1.19.tar.bz2
cd samtools-0.1.19
make

and you will get:

$ ./samtools

Program: samtools (Tools for alignments in the SAM format)
Version: 0.1.19-44428cd

Usage:   samtools <command> [options]

Command: view        SAM<->BAM conversion
         sort        sort alignment file
         mpileup     multi-way pileup
         depth       compute the depth
         faidx       index/extract FASTA
         tview       text alignment viewer
         index       index alignment
         idxstats    BAM index stats (r595 or later)
         fixmate     fix mate information
         flagstat    simple stats
         calmd       recalculate MD/NM tags and '=' bases
         merge       merge sorted alignments
         rmdup       remove PCR duplicates
         reheader    replace BAM header
         cat         concatenate BAMs
         bedcov      read depth per BED region
         targetcut   cut fosmid regions (for fosmid pool only)
         phase       phase heterozygotes
         bamshuf     shuffle and group alignments by name


Create a second script (e.g. chroot.sh) and place it in your chroot/ folder.

Now edit the command in your original script to this:

chroot chroot/ ./chroot.sh

Now the script chroot.sh will be executed inside your chroot.


Testing multiple desktops simultaniously

Your problem isn't just benchmarking the systems, it's just basically how you maintain each machine. How, for example, would you make them all install the same package or remove one, or to install a specific update ahead of an automated upgrade and reboot?

There are tools like Landscape (needs a support subscription with Canonical) that makes this side of things a lot easier.

Other than that, I would start out making sure every machine has an admin user with a specific SSH key installed. You could start with one machine and clone that onto all the others. Once you have that you could use something like clusterssh to address a whole load of computers and run the same on each:

cssh -a '/usr/bin/benchmark' admin@host1 admin@host2 admin@host3 admin@host4

If you don't need the long-term installs, you could just magic up a LiveUSB that autoloads your benchmark and sends it off to a central server. Make a few copies and just batch that around the network. Or the same with PXE netboot. All options.


Disable fstab error message at startup when to-be-mounted drive not found

According to man fstab, you can add the mount option nofail. If I recall correct this works for that situation (I did it once, years ago).


apt -get not executing : command line option g (from get) not known

It is apt-get without the space (not apt -get )

In general the syntax is command and then options. -s are short flags and there may be --long-flags as well with two --

apt is also a command, and with the space, you are trying to run apt with the g,e, and t options. As there is no -g option, you get your error.

If you run a non-existant command apttgett or some such you will get a command not found error.

When in doubt, try the man pages. They take a short time to comprehend, and as with all documentation, some are better then others.

man apt

man apt-get


`--no-install-recommends` only specified packages

In this case, as Thomas has answered, midori is not one of the packages recommended by xfce4-goodies, so nothing special needs to be done.

However, in the general case, you can block specific recommended or suggested packages using a hyphen after their name:

apt install xfce4-goodies xfce4-power-manager-

The - forces apt to consider the package for removal, so it won't be installed. Of course, this won't work for hard dependencies, only recommended/suggested packages, and for packages that are one of many candidates providing a hard dependency.

Correspondingly, when removing a package and its dependencies, you can keep a dependency by using a plus after it:

apt-get autoremove xfce4-goodies xfce4-artwork+

Any of the installation and removal subcommands of apt and apt-get can be used for both installation and removal thus.


Why is my upgrade fetching speed so slow?

I'm currently downloading the same update, and it's downloading slightly over 100kb/s while my actual down speed is about six times that right now.

I'm assuming that as the update just started popping up on everyone's desktop today that lots of people are downloading it right now and so the servers are a little overtaxed.

There's nothing "wrong" with the servers, it's just that they only have so much capacity.


Ubuntu 20.04 bluetooth sound playing issues

Unfortunately, PulseAudio Bluetooth stack is not very reliable, hope PipeWire will resolve these issues.
For me I found BlueMan quite usable, whenever this issue occurs I simply disconnect and reconnect my headset from Blueman.
Make sure your audio profile is selected as A2DP Sink.
Give it a try, hope this will resolve your issue.
Edit: Regarding headset mic issue I followed this - Bluetooth headset Mic is not detected


Ubuntu 13.04 - Shutdown hang at purple ubuntu loading screen

I also face the same problem frequently! I installed a new version of ubuntu13.04 64bit.

Also, when starting the ubuntu13.04, I have to run two times of this command!

sudo service lightdm restart

It seems that some driver or software problem makes it happen.


WiFi (rtl8723be driver) is gone in ubuntu 20.04

I found this article. It solved my problem. Now my wifi is working.


Update 2020: just use this script from my repo here and be done: eRCaGuy_dotfiles...touchpad_toggle.sh
Original answer:
Here is a solution which works perfectly (tested recently in Ubuntu 14.04, 18.04, and 20.04):
sudo apt update
sudo apt install imwheel
gedit ~/.imwheelrc

Copy and paste the following into the newly-created .imwheelrc file (that you just made in your home directory via the gedit command above):
".*-chrome*"
None,      Up,   Button4, 3
None,      Down, Button5, 3
Control_L, Up,   Control_L|Button4
Control_L, Down, Control_L|Button5
Shift_L,   Up,   Shift_L|Button4
Shift_L,   Down, Shift_L|Button5

3 is the "scroll speed multiplier." Use a larger number for faster scrolling, or a smaller number for slower scrolling. The ".*-chrome*" part says to apply these scroll wheel speed increase changes ONLY to chrome.
Run imwheel -b "4 5" to test your settings. When done testing, run killall imwheel to kill it, then make your edits to .imwheelrc, as desired, and run imwheel -b "4 5" again for more testing. Be sure to fully close and re-open Chrome each time you restart imwheel too, to ensure its new settings take effect. This must be done by right-clicking the little Chrome icon in the top-right of your desktop pane and going to "Exit".
Also keep in mind that if you are using a cheap mouse, your scroll wheel decoder may be lousy and miss encoder counts when moving the wheel fast. Therefore, in such a case, move the wheel at a reduced speed when testing the effect of imwheel, so that your mouse doesn't miss encoder counts on the scroll wheel, making you think imwheel isn't working right when it's really just your cheap hardware's problem.
Add imwheel -b "4 5" to Ubuntu's "Startup Applications" to get it to run every time the computer starts.
As Steven C. Howell says here:

Note that using the option -b "4 5" restricts imwheel to only affect the scroll wheel, discussed here.

Another answer by "tvn" here: https://askubuntu.com/a/304653/327339.
More answers here: Increase mouse wheel scroll speed.
Reference notes:
I am not the original author of the answers linked-to above, rather, user "tvn" and others are, although tvn's answer is lacking in that it replaces mouse scroll wheel movements with multiple arrow-key Arrow Up and Arrow Down key presses, which means you have to click in a window for it to take effect, and some things like the browser-based Jupyter Notebook Python programming environment scroll horribly like this! Therefore, Steven C. Howell gave an improved answer which keeps the scroll wheel mapping to the scroll wheel, instead of to keyboard up and down keys, but his answer is lacking in that it applies this new scroll wheel scaling to everything on your computer, so I just modified this answer 27 Aug. 2018 to reflect Steven Howell's answer, but with the addition of adding ".*-chrome*" to the top of the ~/.imwheelrc file so that these new scroll setting apply only to your Chrome browser, which is really what I want. Note also, I have made several significant and important edits and contributions to tvn's answer linked to above, but now I think this answer here is much better, and it's deviated too much from tvn's answer to even attempt to edit his answer further.
Tested in Ubuntu 14.04 LTS.
Update 3 Mar. 2019: tested in Ubuntu 18.04 LTS as well, and it seems the effect takes place immediately in Chrome now each time you run killall imwheel and then imwheel -b "4 5" to test new settings.
Help, my touchpad/trackpad is glitchy when scrolling!

This section added 22 June 2019:

Depending on your computer and hardware, the above settings may work best with a mouse with a scroll wheel. On a track pad (again, this may or may not apply to you or your computer) it may make the result very glitchy when trying to do two-finger scrolling on the touch pad. I have a shortcut key (Ctrl + Alt + P) set up to run a script which enables/disables my track pad so I don't bump it while typing and using a mouse, yet so I can still easily enable it for when I don't have a mouse and/or someone else who loves touch pads wants to use my computer. To fix the glitchy scrolling caused by imwheel when using the touchpad, I've just added the following to my script:
When the touchpad is disabled, enable imwheel so my mouse scroll wheel will work well:
imwheel -b "4 5"

When the touchpad is enabled, disable imwheel so my touchpad two-finger scrolling will work well and not be glitchy:
killall imwheel

Doing the above is especially important for my HP Spectre x360 Ultrabook (Model 13-4193nr, and running Ubuntu 18.04), which otherwise has horribly glitchy two-finger touchpad scrolling when imwheel is enabled.
Here is my full touchpad toggle script with those 2 imwheel lines added as described just above:
File "~/bin/toggle_touchpad":
(I keep the latest version updated here: eRCaGuy_dotfiles/.../touchpad_toggle.sh).
#!/bin/bash

# GS_toggle_touchpad.sh
# - toggle the touchpad on and off

# Gabriel Staples
# Written: 2 Apr. 2018
# Updated: 12 Sept. 2019

# References:
# - https://askubuntu.com/a/874865/327339
# - https://askubuntu.com/questions/844151/enable-disable-touchpad/1109515#1109515

# Search for id number of "TouchPad" OR "Touchpad" in `xinput` list; manually type `xinput` to see all your devices
read TouchPadDeviceId <<< $( xinput | sed -nre '/TouchPad|Touchpad/s/.*id=([0-9]*).*/\1/p' )

state=$( xinput list-props "$TouchPadDeviceId" | grep "Device Enabled" | grep -o "[01]$" )

echo "TouchPadDeviceId = $TouchPadDeviceId"
echo "state = $state"

if [ "$state" -eq '1' ];then
    xinput --disable "$TouchPadDeviceId"
    zenity --info --text "Touchpad DISABLED" --timeout=2
    imwheel -b "4 5"
else
    xinput --enable "$TouchPadDeviceId"
    zenity --info --text "Touchpad ENABLED" --timeout=2
    killall imwheel
fi

Touchpad toggle script source: Enable/disable touchpad
Now just run toggle_touchpad from the command line, or associate it with a keyboard shortcut like Ctrl + Alt + P like I have.
References:

Get the latest version of this script from my repo here! eRCaGuy_dotfiles...touchpad_toggle.sh
Enable/disable touchpad
For new entries to fix scroll speed for Slack and Sublime Text 3 as well, see my latest ~/.imwheelrc file in my project here, and see also my new answer here answer: How do I change the mouse wheel scroll speed in Sublime Text 3?.


KDE/Plasma OSD message doesn't disappear automatically

This is a bug (I was very annoyed too), and it looks to be resolved in Plasma 5.3. You are using 5.2. So I whould update to latest Plasma via backports.

Or, if you can wait a bit longer, and want to stay "official": 15.10 release is imminent (end of October) and it will feature Plasma 5.4.

To install Plasma 5.3, you can use this PPA: https://launchpad.net/~kubuntu-ppa/+archive/ubuntu/backports


finally managed to start in recovery mode, delete the huge files that bleachbit made (https://docs.bleachbit.org/doc/frequently-asked-questions.html) and then everything suddenly worked normally again!
If you're a newbie like me, maybe do not mess with bleachbit ;)


Turns out I had a broken symlink at /home/greg/.mozilla after I deleted the the firefox profile from my files area, but didn't remove the symlink.


Is there a way to authorize an ssh machine?

Yes, there is, you can forward your keys without copying them. Instead of ssh user@server you use ssh -A user@server. When you are logged to the remote machine you can check what keys you can use by ssh-add -l.