Trying to create a GtkTreeView from Python, doesn't seem to work

A Gtk.TreeStore and Gtk.ListStore are different in that a Gtk.ListStore is a flat list where you append rows as a list, whereas a Gtk.TreeStore holds parent/child data, so it takes the parent as Gtk.TreeIter and a list as row.

parent_iter = treestore.append(None, ["parent row"])
treestore.append(parent_iter, ["child row"])

http://python-gtk-3-tutorial.readthedocs.org/en/latest/treeview.html#Gtk.TreeStore.append

As for the empty window, have a look at the views section of the docs.


I cannot mount my windows10 partition from Ubuntu 16.04

Try this:

sudo mount -t ntfs /dev/nvme0n1p3 /media/myusername/windows

System doesn't identify the filesystem type. So you have to enter that as ntfs.  If it fails to mount Windows partition as read/write mode you have to disable fast boot mode from Windows. You can follow this guide to disable it. If you need a gui way to mount and mount at startup see this question's first answer. If still doesn't work, your PBR (Primary Boot Sector) may have corrupted. Try to run chkdsk /f from windows and try to mount it again.

Edit: Your partition name doesn't look like sdaxx because youre machine may use SSD instead of HDD hard drive.


How to rollback to an older kernel on 16.04/purge kernel automatically installs new one?

I’ve found the answer myself with the hints from deleted answer by @mikewhatever. (see him in comments, https://askubuntu.com/users/20054/mikewhatever)

The reason is some package is depending on either linux-image-4.4.0-143-generic or linux-image-unsigned-4.4.0-143-generic. So simply purging the signed kernel will trigger an automatic installation of the unsigned one to satisfy the dependency.

So I checked the reverse dependency of linux-image-4.4.0-143-generic

# apt-cache rdepends linux-image-4.4.0-143-generic
linux-image-4.4.0-143-generic
Reverse Depends:
 |linux-image-generic
 |linux-modules-extra-4.4.0-143-generic
 |linux-image-virtual
  linux-image-unsigned-4.4.0-143-generic

And purged all of those reported. Then I am able to purge linux-image-4.4.0-143-generic painlessly.

see: apt-get -- remove triggers a package install?


Launch a command from a bash script in another shell

If you login to a remote machine without password (using ssh keys) you can do the following trick ssh user@remoteMachine 'bash -s' < local_script.sh

Additional possible variants can be found in this topic


Samsung Galaxy S2 in download mode breaks lsusb

I've found my samsung intercept is very finicky about USB. Try another cable? Try another port? Try rebooting? On some laptops it'll only work -sometimes-.

This isn't necessary an answer, but it's just too long to put as a comment. Please look into whether the following will work-

My suggestion is to avoid using Download mode altogether. USB is too finicky and it's not worth the risk. This is what I would do on the intercept. You should see if you can't find something like flashimg that will allow you to flash directly from the phone.

Get temporary root. (use gingerbreak?) if you don't already have.
Flash Clockwork recovery using flashimg.bin
Flash update using clockwork recovery.


slow login to the desktop and xsession errors

Run $ sudo rm /var/crash/* That seems to speed up the login process. Maybe update-notifier-crash tries to parse these files???

There are a number of other questions discussing Ubuntu error reporting:

Getting "System program problem detected" pops up regularly after upgrade

Why is the file /var/crash/_usr_lib_empathy_empathy-chat.1000.upload empty?


jstest-gtk only remaps the axis for the old /dev/input/js0 interface, which is however not used by any modern game. You can force it's use in SDL1 based games with:

 SDL_JOYSTICK_DEVICE=/dev/input/js0;export SDL_JOYSTICK_DEVICE

but since even SDL1 games are getting kind of old that will be of limited use as well.

For SDL2 based games there is the SDL_GAMECONTROLLERCONFIG environment variable which allows you to remap the joystick directly. If you are using Steam you can configure your controller in Big Picture Mode and it will automatically set that variable for you.


Years later and there still doesn't seem to be an easy way to do it, so I had to kludge together a solution.

Firstly, type out your text in ALL CAPS.

Secondly, select the last letters of each word and change the font size.

And you're done.

This is the quickest and easiest way to edit a small amount of text, taking only seconds to do. If you need to do it with a lot of text then I suggest finding a better solution.

Note: The edit box seems to be buggy and loses the selection, or won't resize. It is best to avoid using it if possible. This may just be my version of Gimp however. YMMV.

Gimp 2.8.10


Keyboard Issue for Asus Vivobook Flip TP 412U

After several attempts at troubleshooting the current 18.04 release and after updating the firmware (UEFI) the problem persisted. The conclusion is that the kernel of that release has poor support for this hardware.

Installing 19.04 provided the proper support for the detachable keyboard that the previous release/kernel lacks.


How do I connect to password protected servers in nautilus 3.6?

It's a simple solution but did you try adding a trailing slash to the end of the server location? (ex. davs://server.location.com:0000/ instead of davs://server.location.com:0000)

I couldn't connect to my FTP server from Nautilus 3.6 until I added the trailing slash.


You can find missing files with

apt-file update
apt-file find scrnsaver.h

Which results in

libxss-dev: /usr/include/X11/extensions/scrnsaver.h

You also need the debug symbols to that package that you will find with

apt-cache search libxtst|grep dbg
apt-cache search libxss|grep dbg

So this will be libxtst6-dbg and libxss1-dbg

so this works fine:

sudo apt-get install autopoint intltool libxtst-dev glib-2.0 python-cheetah \
             glibmm-2.4 gtkmm-2.4 libxss-dev libxtst6-dbg libxext6-dbg libxss1-dbg
./autogen.sh
./configure
make
sudo make install


fn keys to change keyboard blacklights not working

Google gave with the following bug repport. Apparently there is a ppa which fixes it.

Please open a terminal with Ctrl + Alt + T. Copy & Paste the following lines:

On a 64-bit Ubuntu

  wget http://ppa.launchpad.net/flozz/flozz/ubuntu/pool/main/a/asus-kbd-backlight/asus-kbd-backlight_0.1~ppa5_amd64.deb
  sudo dpkg -i asus-kbd-backlight_0.1~ppa5_amd64.deb

On a 32-bit Ubuntu

  wget http://ppa.launchpad.net/flozz/flozz/ubuntu/pool/main/a/asus-kbd-backlight/asus-kbd-backlight_0.1~ppa5_i386.deb
  sudo dpkg -i asus-kbd-backlight_0.1~ppa5_i386.deb

Reboot your system.


How to access a /media folder that has been mounted from a external hardrive?

media folder that has been mounted is itself is in root directory as
  home.

1. / – Root
2. /bin – User Binaries
3. /sbin – System Binaries
4. /etc – Configuration Files
5. /dev – Device Files
6. /proc – Process Information
7. /var – Variable Files
8. /tmp – Temporary Files
9. /usr – User Programs
10. /home – Home Directories
11. /boot – Boot Loader Files
12. /lib – System Libraries
13. /opt – Optional add-on Applications
14. /mnt – Mount Directory
15. /media – Removable Media Devices
16. /srv – Service Data

  It's like:

  /home/testfile.
  /media/testfile.


Yes, it is possible. Since you've Windows 8.1 already installed, just start the installer of Ubuntu and proceed. It should detect Windows 8.1 and offer an option to install Ubuntu too.


Solution for Ubuntu.

Update and install necessary packages.

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get install libstdc++5:i386 libx11-6:i386 libpam0g:i386 -y

Get snx_install.sh file and install.

wget https://starkers.keybase.pub/snx_install_linux30.sh?dl=1 -O snx_install.sh
chmod a+rx snx_install.sh
sudo ./snx_install.sh
sudo ldd /usr/bin/snx

3.1. Run snx directly.
snx -s CheckpointURLFQDN -u USER
# signature saved to /etc/snx/USER.db

3.2. Or better, make configuration file in your HOME folder.
echo "server example.com
username user@example.com
reauth yes
" > ~/.snxrc

4.1. Then you can simple connect.
snx

4.2. And disconnect.
snx -d

Download snx app for android.

https://play.google.com/store/apps/details?id=com.rsa.securidapp

Ask the provider to sent you link via email. You can open on cellphone via SecureID.

Enjoy!


Disconnected external monitor stays the primary monitor after disconnecting

When in the described situation, that the main monitor is there in Ubuntu, but there is no actual monitor, I found one solution. Simply run the "Displays" thing, well press the Super button, type "Displays", and hit Enter.

As soon as that configuration window open, it realizes that there is no monitor, and all windows are moved to the laptop's monitor. You can select alter the primary monitor so that, you don't have to go through this always.

Other solutions are welcome too.


How to copy multiple ".gz" files from the sub directories to one directory by grepping a keyword?

The zgrep command should help, I have this example

mv $(find a/*/* -type f -name "*.gz" -exec zgrep -l 'nob' {} \;) /tmp

The command does the following:

zgrep like grep uses the -l option to return the filenames that contain the search word nob
mv $(find a/*/* -type f -name "*.gz" -exec zgrep -l 'nob' {} \;) /tmp will move any returned files with extension .gz to the /tmp folder


Ubuntu Server: Boot Messages on terminal 7 (video) Why?

You can change this with a kernel parameter:

root=/dev/sda1 console=ttyS0,57600n8 console=tty1

will make all messages go to tty1. You need to add this to Grub and How do I add a kernel boot parameter? explains that.


A forum user suggests not using round robin (Source)

So change:

create=mfsrr:10000000

To:

create=msf

There are other create options in the manpage


Nautilus can not display FTP files, FileZilla and comman-line 'ftp' can

It is a gvfs issue, where it cannot connect to some FTP servers. See the relevant bug report at https://bugzilla.gnome.org/show_bug.cgi?id=516704
If you can identify a public FTP server that uses the same FTP server software, it might be possible to identify what aspect of the FTP protocol is at fault, and ask for a fix.
Therefore, for now, you can use an alternative FTP client.


Ubuntu Disks says : disk is likely to fail soon

at least you can see "Relocated sectors count" in the SMART report.
That's not good. It says that disk is already using relocation blocks
and so there are already bad blocks on your disk. After some time there
will be no more free relocation blocks and relocation won't be possible..
Then UNC errors appears and your disk will be dead.

Make backup asap and switch to new one if you like your data :)

  Reallocated Sectors Count S.M.A.R.T. parameter indicates the count of
  reallocated sectors (512 bytes). When the hard drive finds a
  read/write/verification error, it marks this sector as "reallocated"
  and transfers data to a special reserved area (spare area). This
  process is also known as remapping and "reallocated" sectors are
  called remaps. This is why, on a modern hard disks, you will not see
  "bad blocks" while testing the surface - all bad blocks are hidden in
  reallocated sectors.


http://www.iasptk.com/ubuntu-fix-broken-package-best-solution

After trying

sudo dpkg --configure -a

and

sudo apt-get install -f

the problem of a broken package still exist the solution is to edit the dpkg status file manually.

sudo gedit /var/lib/dpkg/status

(you can use vi or nano instead of gedit)

Locate the corrupt package, and remove the whole block of information about it and save the file.

if this dont help u...go through

http://ubuntuforums.org/showthread.php?t=1642173

http://www.linuxquestions.org/questions/debian-26/sub-process-usr-bin-dpkg-returned-an-error-code-1-a-171107/


Yes, this is well beyond the system requirements for Ubuntu 13.04.

"A Pentium 4, 1GHz system is the minimum recommended for a desktop system."

"With Desktop  64 megabytes    512 megabytes   5 gigabytes"

There is no guarantee that the graphics chip (ATI Mobility Radeon HD 4530) won't cause issues when you install, as graphics is still a bit of a sticking point, even on the latest Ubuntu release, but you will definitely have more than enough power to run it.


What is the Tomcat installation directory?

There are three important directories for Tomcat:

/etc/tomcat{X} for configuration
/usr/share/tomcat{X} for runtime, called CATALINA_HOME
/usr/share/tomcat{X}-root for webapps

The alternative path to Tomcat, called CATALINA_BASE, is /var/lib/tomcat{X}

The temp folder for Tomcat is /tmp/tomcat{X}-tomcat{X}-tmp

All the above paths work for Tomcat 6, 7, and 8. Replace {X} with the appropriate Tomcat major version number, e.g. /etc/tomcat8.


Why is a repository still in /etc/apt/sources.list.d after removing it with add-apt-repository --remove?

add-apt-repository --remove doesn't actually remove the repository but disables it. If you want to remove the repository along with any package it may have installed you can by using ppa-purge:

sudo ppa-purge ppa:cassou/emacs

http://www.webupd8.org/2012/11/install-ppa-purge-with-multi-arch.html

NOTE: This will downgrade any packages you might have installed from the PPA to the version available in the main repositories. As explained in man ppa-purge:

NAME
   ppa-purge - disables a PPA and reverts to official packages


What is the default cursor set called in Ubuntu 20.04 onwards?

The default cursor theme is called "Yaru".
It is located in /usr/share/icons/Yaru/cursors.
You can set/change the default cursor theme using Gnome Tweaks (installed using sudo apt install gnome-tweaks).


You should just be able to specify which one you like in display preferences.  I had to drag them to the position I wanted them to be in, and click apply.


This post on reddit says that it's because of a broken dependency and the fix for that is:

sudo apt-get install python-gobject

After typing that in a terminal, I'm now able to start GUFW.


Can I use my USB keyboard and mouse on the Ubuntu flagship tablet

Yes, you will need to buy a micro USB to standard USB hub. I bought this one:
https://www.amazon.co.uk/gp/product/B00EUZN6MA/ref=oh_aui_detailpage_o02_s00

I use my m10 with a bluetooth keyboard, mouse and speakers (all separateluy connected) and use the USB hub for managing a GPS device. All work together. Just to confirm though that I have also previously tested the tablet with a USB mouse and keyboard via the above device.

I have not tried connecting an external monitor. You will need micro HDMI to standard HDMI converter for this.

Note that is is currently challenging to install dev tools on the device. Read the other questions on here to see if this will be a problem for you.


Press the button "Clear and Rebuild Cache". This action will recreate cache dirs as you set it in cache_dir option


How to downgrade from Gnome Shell 3.6.1?

I think that the only solution is to reinstall 12.04 and/or ask to extension developers to upgrade their extensions.


play -n -c1 synth 10 whitenoise band -n 100 20 band -n 50 20 gain +25  fade h 1 10 1

Insert the total duration after synth (in this case 10 seconds )
Also supply the duration to fade so this function can apply the fade-out time (1 second in this example) at the right moment (i.e. at the ending of the track)

If you want to record this, just do:

sox -c1 -n result.wav synth 10 whitenoise band -n 100 20 band -n 50 20 gain +25  fade h 1 10 1

This will dump the resulting sound in result.wav.


try this:

Simple way, you can change the login background using Nautilus:

open Nautilus (in root mode)

go to /usr/share/backgrounds.

cut/move/delete "warty-final-ubuntu.png"

then choose the picture you want ( .png format)

rename it to "warty-final-ubuntu.png"

then move it back to /usr/share/backgrounds.


Use swaks for testing email sending. To install:

sudo apt install swaks

You can just run swaks command and input the fields when prompted or pass the arguments in CLI mode, for example:

swaks --to user@example.com --server test-server.example.net


First of all you need to remove any previous installations of Libreoffice.(if any)

sudo apt-get remove --purge libreoffice*
sudo apt-get clean
sudo apt-get autoremove

There are 2 ways to install:

1.

Add the right repository:

Warning: if you have another LibreOffice PPA installed, you might have to remove it first

Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the commands below:

sudo add-apt-repository ppa:libreoffice/libreoffice-4-0
sudo apt-get update && sudo apt-get upgrade

2.

Download the right Libreoffice package for you, and press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, navigate to the folder where the file was downloaded extract the archive. run the command below:

tar -xzvf libreoffice*.tar.gz

Then do

cd libreoffice*/DEBS
sudo dpkg -i *.deb

Once done, then

cd desktop-integration
sudo dpkg -i *.deb

That's it.


Yes. Any KDE app will work under Unity.

All apps use the same "core" backends, namely the Ubuntu main packages. However, KDE apps need their own dependencies (the KDE/QT libraries). When you install the app through the Software Center, it will download not only Connect but all of the required KDE libraries.

The actual KDE environment won't be installed unless it is necessary, and I'm not sure whether it is needed for Connect.

Kubuntu, Lubuntu, and *buntu are all just derivatives of Ubuntu and can all run any program built for Ubuntu, as long as its dependencies are set.

Just a warning though:

The KDE/QT UI clashing with the Unity/GTK UI can look pretty ugly. A good theme could sort this out though.

If you installed it and it didn't appear to work, you might have to manually run the command. Sometimes menu entries aren't updated.


How do I troubleshoot network issues with my VPS?

Firstly if you believe this is a vendor issue that they're not addressing, I'd strongly consider migrating away. I gave VPS.net the benefit of the doubt when their SAN kept crashing (taking down all the VPSes in the process) but after a few months of "We've fixed this for good" and it still crashing, I had to vote with my wallet.

It's surprisingly easy to start a VPS company (you really only need a bit of datacenter space and some servers) so they're not all equal in technical ability even before you get to customer service.

But in terms of getting to the bottom of the problem, I'd first look at stopping things ending up in swap. Leave swap on but do whatever you have to do so you're not pushing things that far. Rein in the Java application or add more RAM. And see what happens. If this is very regular, you shouldn't have to wait long (or pay much) to see a result.

Same with CPU. If you have things running at 100% for extended periods, you want to make sure they're not interfering with other applications. The most simple way to work this can be done by setting the nice value of whatever applications are rampant to something positive. A nice value of something like +10 should let the system get full priority of the resources before your applications. Sidebar: Nice values basically mean the're more polite when it comes to CPU scheduling. Something with a low (eg -20) nice value means they'll get prioritised over all other things with higher nice values.

If you can, expand your testing to other local network items. If they provide a DNS resolver (as a lot of server companies do), ping that constantly (well, a few times a minute) and log the results. If you can still access that during periods of downtime, it's less likely that it's your fault.

And as I say, if this isn't your fault, move. If you spend any more time trying to fix this, you're outweighing any conceivable benefit of staying with these people. I personally have a very good and long experience with Linode but there are lots of good companies out there.


why I can't install kernel sources from repository

Ubuntu 14.04 came with the 3.13 kernel, not 3.2. It seems you are still running on an old kernel which was left around from an upgrade from 12.04. You should reboot into the newer kernel, and then purge all old kernels from your system.


What are the differences between Desktop, Server, and Alternate Installs?

(just for the sake of doing it I have also included Ubuntu Netbook Edition here)

Similarities between all versions

All versions support encryption of the home folder.
All versions use the same application repositories, so that you can for instance install web and mail servers on Ubuntu Desktop or Ubuntu Desktop on a Ubuntu Server or Ubuntu Netbook system (by installing the ubuntu-desktop package), and any other combination.

Ubuntu Desktop

The installer is called Ubiquity, which is written specifically to be a GUI installer for the Desktop/Live CD.
Includes the Wubi installer for installation for Windows systems
Installs the basic Ubuntu system, in addition to the ubuntu-desktop package and all its dependencies, including GNOME and various applications, such as Firefox and Empathy.
You can try the system directly from the CD, and it has a graphical installation.

Ubuntu Server

The installer is debian-installer, which is text based and is shared with Debian.
It basically is just the base Ubuntu system, but during the installation you can optionally install services such as a web or mail server by using tasksel.
Ubuntu Server does not include a graphical user interface so it does not install the applications included in the ubuntu-desktop package, such as GNOME.

Ubuntu Netbook

Installs the basic Ubuntu system, in addition to the ubuntu-netbook package and all its dependencies. It also uses the Unity interface instead of the default GNOME interface.
The installation method is very similar to Ubuntu Desktop

Ubuntu alternate installer

The installer is debian-installer, which is text based and is shared with Debian.
The alternate installer installs the ubuntu-desktop package, just as Ubuntu Desktop does.
It is mostly intended for installing or upgrading Ubuntu on machines where this cannot be done in other ways. For instance, I had to use this CD when installing Ubuntu on my machine, because none of the LiveCDs would work.
Allows setup of LVM and LUKS encrypted file systems
Has an option for an "OEM Install", which allows you to install the OS but leave the personalization like username and password as part of the first boot.
Option to install an LTSP Server.


Error get while installing ardupilot on virtualbox ubuntu 14.04.3

Well, the command that you have typed has a little typo. Here's the command to install git:

sudo apt-get install git

And to clone the git repository, you have to type the command:

git clone git://github.com/diydrones/ardupilot.git

EDIT: If you want to combine the commands then, type:

sudo apt-get install git && git clone git://github.com/diydrones/ardupilot.git


Record screen at bootup using ffmpeg in 5 minute segments (12.04)

I ended up using the .profile file and changing my code around to these:

In .profile:

if [ "$RECORDISRUNNING" != "1" ]; then
    export RECORDISRUNNING=1
    /home/swuser/sleep.sh &
fi

In sleep.sh:

#!/bin/sh
# sleep for 30 seconds then call record.sh
sleep 30
/home/swuser/scripts/record.sh &

In record.sh

#!/bin/sh
# Check to see if there is a display, and if not, exit with error code of 1
if [ -z "$DISPLAY" ]; then
exit 1
fi
# Export the main display
export DISPLAY=0.0
# Set variable now to todays date and the time right now in Hours-Minutes-Seconds_Month-Day-Year
now=$(date +'%H-%M-%S_%m-%d-%Y')
# Start recording using ffmpeg at 5fps with a time limit of 300 seconds(Five Minutes) to file $now
ffmpeg -f x11grab -s 1024x768 -r 5 -t 300 -i :0.0 /home/swuser/Videos/$now.mp4
# Call the script again (to continually record in 300 second increments)
/home/swuser/scripts/record.sh &

And that about wraps it up.


Non-gtk desktop programs on Xubuntu 18.04 look terrible

qtconfig-qt4 works for applications which are installed as .deb-packages and thus are integrated properly in the system.

Applications installed as snaps run in an isolated environment and you can't change their appearance with qtconfig-qt4.
I have qtconfig-qt4 installed and the only change I made is the GUI-style in the Appearance-tab, changed from default to GTK+:

Clementine installed as a .deb-package looks like this:

But Clementine installed as a snap looks a bit ugly:

Clementine and Hexchat are available in both formats in gnome-software, as .deb-package as well as snap. When you install an application via gnome-software, scroll down to see the Details and take a look at the Source of the application.


Difference in file count (Linux and Windows)

Windows cannot see the Ubuntu files, so you are getting count of Windows files only.

Ubuntu can see Windows, so you are getting file count of Windows plus Ubuntu.

Note that within Ubuntu you can get different file counts using different commands. For example:

rick@alien:~$ ls /mnt
c  d  e
───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:~$ locate * | wc -l
861646
───────────────────────────────────────────────────────────────────────────────────────────
rick@alien:~$ find / * 2>/dev/null | wc -l
1262530

Notice there are three Windows NTFS partitions that Ubuntu "sees".
The locate command only counts 861,646 files. It excludes Ubuntu system files and /tmp directory files. It includes Windows though.
The find command counts 1,262,530 files and directories. It is also includes Windows plus Ubuntu system files and the /tmp directory files.


How do I add a border around windows but keep the current theme?

The file is /usr/share/themes/Ambiance/gtk-3.0/apps/unity.css

change
      -UnityDecoration-extents: 28px 0 0 0;
to
      -UnityDecoration-extents: 28px 1px 1px 1px;

logout and log back in and see effect the changes.

Thus, in your local copy, make the "1px 1px 1px;" change in the file ~/.themes/Ambiance/gtk-3.0/apps/unity.css

Enjoy! : )


Can't find wifi drivers for 0bda:f179 Realtek Semiconductor Corp

You can install rtl8188fu driver with dkms via this repo (has install instruction).


How can I determine X resolution from CLI without randr?

you can grep output of xdpyinfo or xwininfo -root or xprop -root.


How can I add a route that is "on the link", directly connected to the interface even if the IPs are not the same?

Starting with netplan 0.34 (now in Ubuntu 18.04), you can add "scope: link" to your route in netplan config, with something like this:

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      [...]
      gateway4: 62.210.0.1
      routes:
        - to: 62.210.0.1/32
          via: 62.210.0.1
          scope: link


I would recommend both. Two totally different items but it will both benefit you in the long run. If you have an intermediate experience on Linux already. Openstack skills is a complement/supplement to it which provides an opportunity to experience a new platform directly related to cloud implementation. two cents.


This change is neither secure nor insecure, in so much that it doesn't change 'hackability' or not.

However, you actually won't be receiving data correctly unless you set your mydomain configuration option in the PostFix configuration.

The first version you had, with the original items commented, should be sufficient to 'receive' mail at your domain.  The relevant line - mydestination = $myhostname, localhost.$mydomain, localhost, fantasy.cmtim.si - was not commented out so it should have worked without much additional configuration.


Yes, the GNOME 3 PPA is an experimental developer preview and is not recommended for install, even if you are only using Lubuntu.


What exactly is GStreamer and should I install it?

To quote this post from the gstreamer-devel mailing list:

  ffmpeg/libav is a library that contains all kinds of codecs, support
  for  various container formats, some filters, etc. It's a library
  providing  some API to use these things separately.

  GStreamer is one level/layer above that and a generic multimedia
  framework, based on pipeline graphs (check Wikipedia for the pipes and
  filters software design pattern for example). It allows you to put
  together arbitrary multimedia processing pipelines built from
  different  components (we call them elements) that all do different
  tasks.  GStreamer provides generic mechanisms to put together these
  pipelines,  control them, synchronize data flow, etc.

  Some of these elements are for example decoders, that could for
  example  be implemented by using ffmpeg/libav. Others could be filters
  or  elements that read data from a network stream, or write data to a
  file,  or ...

It doesn't compare because there's nothing to compare with in the default Ubuntu. KDE systems use Phonon, which I think plays the same role.

As for the conflicts, you probably didn't run apt-get update. ubuntu-restricted-extras indirectly depends on libavcodec57:

ubuntu-restricted-extras

ubuntu-restricted-addons

gstreamer1.0-libav

libavcodec57


Resize hard drive partition to make more space for /var

I'll take a shot at an answer for this, and assume that if I'm drastically wrong you have a good backup!  I'm not entirely sure this will work, but it seems reasonable.

1st:  Most of what you are going to need to do, you can't do from a running linux on your hard disk:  Linux makes a lot of use of the /var directory structure, so the first thing to do is to make a live USB or CD so that you can manipulate your HD from 'outside'

2nd:  Read up on the 'mount' command, and 'umount'.  You'll need them.

3rd:  Read up on a suitable copy that hopefully retains permissions and subdirectories.  I think you're going to want cp -a

procedure, in basic terms:

a)  Boot from the live CD/USB.  Choose the 'Try Ubuntu option.  Open a terminal and get gedit sudo apt-get install gedit

b) mount /dev/sda2 as a suitably named directory, such as /mydrive mount /dev/sda2 /mydrive

c) mount your too-small /var, /dev/sda5 as another directory, /oldvar mount /dev/sda5 /oldvar

d) copy the /oldvar to a new /var structure  cp -a /oldvar /mydrive/var

e) edit your fstab so that the old /var does not get mounted.  gedit /mydrive/etc/fstab

Look for the line of code in that file which mounts the /var filesystem, and put a '#' at the start of that line so that it is commented out

f)  reboot and cross your fingers.

Note that we have not deleted the partition at /dev/sda5, and that we only commented out the fstab entry corresponding to your /var directory.  If this fails, you should be able to boot again from the live USB, edit the fstab file again to remove the comment, and be back in business.


Can't access Internet on one PC in my Network

The default gateway on A is not in your network. You are using 192.168.21.x/24, but your gateway is 192.168.20.154, which is not in the same network segment.

Besides that, as vidarlo states in the comments, it is very strange that you use 20.0.0.0/24, since that block is part of the public ip space. There are reserved blocks you can use called private ip space.

Private network on Wikipedia


Very interesting Bonus 1.5 GB "space" from .... space?

Very interesting. I just learned what this is myself. You can see the actual information here, but will still summarize it for you.

As you can see from the far left side of that "drive", is that it's a different mount point. /dev/loop0, to be specific. You can also see that your USB device is being recognized as a cdrom.

The 1.5GB of space is known as a loop device. To my understanding, it is used for holding installation files and programs while they are running so in the event your "CD" is removed, the program won't crash and potentially corrupt your system. It is also much faster to run a program locally, rather than through your USB port.

I hope this helps!


Not easily, no. The files have been deleted, you will need to use a tool that can recover deleted files, there is no undo for this. For help on recovering deleted files, see this Q&A:

How to recover deleted files?

Recreating the user is the easy part:

adduser george

For future reference, user management should be done with adduser and deluser instead of useradd and userdel.


Removing exo-utils worked for me perfectly.


Should I switch my graphics mode in the BIOS to avoid using Bumblebee?

If you're looking for saving power, that's the recommended method: changing the BIOS setting to Integrated. It'll indeed turn the nVidia card off and rely on the Intel iGPU only. There is no need for reinstalling everything.

It'll also mean that you'll have to turn it on each time you want into Windows to play games. Not ideal.

Bumblebee supports power management scripts (although the use of it is considered experimental!). Do not use it unless you know what you're doing. https://github.com/Bumblebee-Project/Bumblebee/wiki/ACPI-Removed In the future (1-3 months?), the Bumblebee team has probably a stable kernel module which should allow to toggle the nVidia card.


Building HTML cordova app and running directly on physical device

To test the app in your device, just plug the device to your development pc using a USB cable.

Assuming that your device is recognized by the OS, from the terminal and in app's root directory type:

cordova run --device

Cordova should build the app for your device's platform (assuming you have added a platform during development), copy it to the device and run it automatically.

Tested with Cordova 3.5, Ubuntu 14.04 development machine and Nexus 4 (Android) as the target platform.

For more info about the steps see the documentation for platform guides and the documentation for the CLI (look for the line mentioning how to run on device Alternately, you can plug the handset into your computer and test the app directly:).


Is using Unity Tweak on Ubuntu 14.04 safe?

Unity-tweak is just another tweaking tool such as Ubuntu-tweak or gnome-tweak, yet it's just another application, thus it doesn't to have included in Ubuntu itself since many others aren't also, in addition no tweaking tool was available before by default, then this is not an exception.

Would this affect your system, or cause some problems!! Normally no but, this app as other apps may have some bugs that affect your system. This is not a rule, it's just a possibility that is related to every application you are installing in your system.

Anyway, you can give it a try.


have you tried to verify exit code of the ifenslave of the post-up ?. Documentation says that ifup would fail if exit code is diff from 0


Factory reset windows OS on dual booted system

Do not follow the duplicate as Windows Factory reset might wipe your entire disk!

What you should is it to:

Take a screen shot of your current gparted disk configuration.
Make a full System backup on an external HDD using CloneZilla Live Using Disk to Image.
Do the Windows thing (Off-topic here)

Check in Windows Disk Manager whether that wiped your Ubuntu partitions or not.
If it did not, but Ubuntu doesn't boot, skip to step 6
If it did wipe the Ubuntu partitions, go to the next step.

Boot Ubuntu in "Try" mode
Run gparted again and resize your partitions manually as noted in step #1
Restore your system backup
Optional: Run Boot-repair if Ubuntu doesn't start.


The answer for dependencies is actually listed here: http://www.webmin.com/deb.html

  If Debian complains about missing
  dependencies, you can install them
  with the command :

  apt-get install perl libnet-ssleay-perl openssl libauthen-pam-perl libpam-runtime libio-pty-perl

  If you are installing on Ubuntu and
  the apt-get command reports that some
  of the packages cannot be found, edit
  /etc/apt/sources.list and make sure
  the lines ending with universe are not
  commented out.

I followed the instructions and uncommented  "universe" lines in /etc/apt/sources.list which were indeed commented out as the instructions suggested (the file contains more info if you read it). Note: Only two universe lines were commented out in my file but others were not. I made sure all universe lines were uncommented in the entire file and then saved it.

After following the above instructions dpkg still failed to install webmin, with same message,  then I used the following apt-get force command with no package name. It pushed everything through that didn't go through prior, including the webmin:

sudo apt-get -f install

Success! :)

Note: I found this only minutes after posting the question.
Turns out I was looking for Ubuntu help on the web site menu, but needed to choose Debian help since I'm using the Debian installer.


Ubuntu: How much drive space does it need?

Straight-up Ubuntu with GNOME3 is drive-space-absorbent; Ubuntu Flavours less so. Want a lighter, smaller OS? Well, there's Kubuntu, Xubuntu, Ubuntu Budgie, Ubuntu MATE, and especially Lubuntu, all supported here. (Mint, bless their hearts, has diverged so much we don't support it here.) Pick a Flavour, any Flavour, and you will have oodles of room, even on the 32.
Now that Canonical has seized upon Snaps, OS drives are filling up rapidly. If you don't use them and install from other sources, the OS drive doesn't fill up as rapidly.
eMMCs CAN be upgraded. I threw a 500GB eMMC into a Thinkpad T420. Works great with two different OS on it as well as a /home partition chock full of Stuff. Bought it on Big River Trading Outfit.
If you need more storage, see item 3 above, or add a tiny USB drive or this one which does not stick very far out of the socket for convenience, and leave it there.


Installing Ubuntu 18.04 - Samsung p510 Laptop

With only 2GB RAM, download a 'flavour' with a different Desktop Environment, download from https://ubuntu.com/download/flavours .

The ISO file you use to create a LiveUSB should be checked for download errors by https://tutorials.ubuntu.com/tutorial/tutorial-how-to-verify-ubuntu#0 .

LiveUSB creation is typically done following these instructions on a Windows PC https://tutorials.ubuntu.com/tutorial/tutorial-create-a-usb-stick-on-windows#0

Install it following these steps https://tutorials.ubuntu.com/tutorial/tutorial-install-ubuntu-desktop#0 https://askubuntu.com/a/1188561/197910

Although some flavours use a different installer, the steps are very similar.


How do I create a Python virtual environment in the Ubuntu on Windows App using 'venv' rather than 'virtualenv'?

What I did so far:

Open Terminal
Go to desired directory
Type python3 -m venv name_of_virtual_env

If it doesn't work, could you please update your question to show the output of the Terminal?
EDIT
I just tested venv install on a virtual machine Lubuntu 19.04:
sudo apt install python3-venv
I could then create a virtual environment with above-mentionned command. However I already had Spyder3 installed so some dependencies could have come with it.
And as suggested by Thomas Ward, I share my sources:


Possibly, but that's not a problem because there are over 300 servers all over the world. Check out Edit->Software Sources in the Software Center for available servers. It's advisable to pick a server near your geographic location for faster download speeds.


Install printer Lexmark X4690 (ubuntu 12.04)

It is working now. See the link:

How do I install drivers for a Lexmark X6675 Printer?

or download the file directly:

http://www.mediafire.com/?yowom7gh6vg4fzl


I have not tried this, but I found these instructions here. The link is a couple of years old but the software is still there.

First, some build tools are installed, such as Subversion (svn) for version control. Subversion then pulls the latest stable version of the driver from the Internet and places it in a separate directory line6usb. The next step is to build the driver and install it. If everything works, feel free to remove Subversion and the other build tools.

sudo apt-get install gcc make subversion alsamixergui linux-headers-generic
sudo svn co https://line6linux.svn.sourceforge.net/svnroot/line6linux/driver/trunk line6usb`
cd line6usb
sudo make install

Then you have to find your soundcard with:

cat /proc/asound/cards

This tells you how your Line 6 device viewed by the computer ('hw:' number). Replace 'hw:1' with whatever shows up for your sound card when you type:

alsamixergui -D hw:1

You HAVE to turn the 'monitor' slider all the way down or things will crash (unless the 'svn' site has a newer version that fixes this).


Will python scripts be run when added to /etc/network/if-up.d?

Yes, it should.

Does it have a dot in its filename? run-parts (8) ignores files with dots in their name.


Want to back up using dd, but my present ubuntu installation is 149.04 + 3.81(swap) GB, my target drive is only 149.05 GB

Yes swap holds no persistant data so as long as your Ubuntu machine is shutdown the swap can be safely wiped or even removed.  So I you back up just the ext4, you can restore it later without the swap.


Where does the command make search for libraries

The make command itself does not search for libraries or header files - instead it looks for a Makefile in the current directory (unless an alternative file is specified on the command line using the -f option) and executes the instructions inside. Those are usually instructions to specific compilers such as gcc and/or g++.

The Makefile may add search paths for specific compilation commands using -I (for include files) and/or -L (for libraries) directives. You can find the default search paths in your compiler documentation e.g. GNU gcc: Search Paths or you can list them directly by processing an empty file with compiler verbosity turned up e.g. to see what the gcc include path is

echo | `gcc -print-prog-name=cc1` -v

or to see both include and library path information echo | gcc -xc -E -v - (for C) or echo | gcc -xc++ -E -v - (for C++).

However the question you linked to looks like the output from a ./configure script rather than from a make command. A ./configure script is part of the GNU automake system and is used to create a 'custom' Makefile for the local build environment by figuring out where various components are located on your system. If you have libraries located in non-standard locations, such as other build dependencies that you have also built from source, and installed somewhere like /usr/local/, then it may be necessary to pass those locations to the ./configure script e.g.

./configure --with-foo=/usr/local --with-bar=/opt/bar_3.14

For specific instructions you will need to refer to the README or similar documentation for the package you are trying to build.


I had a similar situation a few months ago. I upgraded to 64GB from 32GB. I changed nothing in the BIOS. I could not boot into Ubuntu at all (I do not have Windows).

After a bit (lot?) of hair pulling, I went into the BIOS and changed the ram frequency down (from 3200 to 2666). Computer booted perfectly.

I do not know if you can change things like ram frequency on your Dell, but that might be a good place to start.


How to edit the text that appears on the Unity login screen?

Although the version of ubuntu you reference is obsolete and completely EOL, you might try doing a reinstall of lightdm with sudo apt-get install --reinstall lightdm


Unable to boot while installing Ubuntu 18.04 in VirtualBox in HP

Your error indicates that your CPU doesn't support the Intel 64-bit ISA.
You can't fix this with a software update, you're gonna need a hardware upgrade to a CPU with 64-bit support.

My personal recommendation is:
Upgrade to a 64-bit architecture with IOMMU support. Then you will be able to do full Hardware Virtualization and IO-Virtualization as well. So check the spec sheets of your preferred MB + CPU vendors.

Your only alternative would be using a full x64 processor emulation, but I don't know of any.


I tried these options to solve the same problem on Ubuntu 18.04LTS:

Insert "comment=systemd.automount" into the relevant mount statements
in /etc/fstab. PROBLEM: This option produced multiple mounts of the
same network shares when I tried to use it for two different network
shares.
Insert "mount -a" into /etc/rc.local. PROBLEM:This seemed to
have no effect! As superuser, create a script with the following text
in directory /etc/network/if-up.d/ and give it execute permissions:
As superuser, create a script with the following text in directory /etc/network/if-up.d/ and give it execute permissions:

#!/bin/sh
mount -a

PROBLEM SOLVED! The last solution works well. Scripts located in /etc/network/if-up.d/ run after a network connection is established. This script then mounts the network shares (and any other pending mounts) already stipulated in /etc/fstab.


How to install clearlinux gcc in ubuntu?

Thanks to @Raffa and i hope @Raffa writes the answer here so i will award him the award.

wget https://cdn.download.clearlinux.org/releases/33030/clear/x86_64/os/Packages/gcc7-7.5.0-440.x86_64.rpm
sudo apt install alien git curl
sudo alien gcc7-7.5.0-440.x86_64.rpm
sudo dpkg -i gcc7_7.5.0-441_amd64.deb
gcc7 -v


Cannot Connect Modem ( /dev/ttySL0 ) Using gnome-ppp - Dial-Up Connection

From the PDA-Net website:

  Since this is just a regular Bluetooth
  DUN connection, you have 3 ways to
  initiate the dialup:

  You can use the Bluetooth software to connect if available. For some
  drivers such as the BlueSoleil one,
  this is the only way you can initiate
  the connection.
  You can open network connections panel and launch the Bluetooth entry.

  For 1 and 2, enter phone number #777
  and empty username/password when
  prompted.


how to access my ubuntu, which is present in my partition?

When you where installing ubuntu, in the section where it asks to write changes to disk, did it ask you to install the bootloader (GRUB) on the disk ?

By chance did you say no ?

If im not mistaken you can use the same USB you used to install ubuntu to try and repair the system. Assuming its a live image it should have a "repair installed system" option and that may help install/reinstall/repair grub in order to successfully boot into the Ubuntu installation.


Can not build Ubuntu Touch project in Ubuntu SDK

You can run your app from the command line though.

Open a terminal
cd into the directory your project is located
qmlscene ~/CurrencyConverter/CurrencyConverter.qml

That would allow you to run your app but I don't know why it wouldn't run from within Ubuntu SDK.


Ubuntu 18.04 mt7601u Disk Writing Problems

I suggest that you blacklist the module. From the terminal:

sudo -i
modprobe -r mt7601u
echo “blacklist mt7601u” >> /etc/modprobe.d/blacklist.conf
exit

You should be all set.


12.04 LTS distro upgrade to 13.04 -- will it still be LTS?

No, 13.04 is not LTS.

You cannot directly upgrade 12.04 to 13.04. You can upgrade 12.04 LTS to 12.10, and then upgrade 12.10 to 13.04. Both 12.10 and 13.04 are non-LTS.

Ubuntu non-LTS have historically been supported for 18 months. New non-LTS will be supported for 9 months. For example, 12.10 is supported until April 2014 (18 months since October 2012). 13.04 it is supported until January 2014 (9 months since April 2014).

Source: Releases - Ubuntu Wiki

About NKN's comment: note that upgrade has two distinct meanings:

You can upgrade 12.04.* to 12.04.3, in the sense that you will have
up-to-date packages for the 12.04 series. This is done by apt-get dist-upgrade
(allows apt-get to install new dependencies if necessary) or apt-get upgrade
(does not allow apt-get to install new
dependencies).
You can upgrade 12.04.* to 12.10, so that you will have packages for the 12.10 series. This is done by do-release-upgrade.


OpenJDK Java 7 missing from "Open With" under file Properties

I don't know how to add the option in the tab of the Open With menu.
But to create a shortcut for the dash, you can use the alacarte application.

Then, you could drag-and-drop the shorcut to add it to your main menu.


Run the below commands on terminal,

sudo add-apt-repository -r ppa:a-v-shkop/chromium
sudo apt-get update


Nvidia-settings won't detect second monitor

So the problem stemmed from the fact that I had my main monitor plugged directly into the GPU, and my second plugged into the HDMI port on my motherboard (with integrated graphics).

This was not a problem in Windows but neither the NVIDIA settings nor default Displays settings detected the second monitor, but I noticed that the second was the default display when I was using a VC for example.

So I switched around come cables, and plugged both directly into the GPU, and now I have both monitors set up correctly :)


Can't boot without recovery after I installed a package to change the login screen

For 1st one, Try This

For 2nd one, Seems like Greeter Has Been Overidden. Try to do:-

   sudo nano /etc/lightdm/lightdm.conf

And Find a line that looks like

greeter-session=xxxx

to

greeter-session=unity-greeter

And Press F2 to save it.


Try using nethogs to see which processes are using the network:

Install nethogs using the Software Center or a package manager (sudo apt-get install nethogs).
Open a terminal and run "ifconfig" to list your network interfaces. If you connect your computer with a wire the relevant interface will likely be something like eth8. If you connect wirelessly it'll be something like wlan5.
Open a terminal and run "sudo nethogs interface", according to the relevant interface from before. Wait a bit. When a program accesses the internet, it will show up in the display.

To see what websites are being accessed, try running in a terminal:

netstat --protocol=inet --program

to list connections currently open. The output will show lines like

tcp        0      0 myhostname.local:59957      stackoverflow.com:http  ESTABLISHED 23331/firefox


Install a desktop that uses lesser resources like Lubuntu or Xubuntu. To install lubuntu type the following in terminal:

sudo apt install lubuntu-desktop

To install xubuntu, type the following in the terminal:

sudo apt install xubuntu-desktop


How to install driver for ReakTek rtl8821ce with NO ETHERNET PORT

You can always go online on any system having a USB port.

Connect your phone with a USB cable and turn on USB modem mode there.

It is a lot easier for a newbie that to manually install many packages with dependencies.


Is ubuntu installed in my pc? if yes how can i run it?

Ubuntu might have been pre installed then wiped and installed Windows 7. Depends where you have purchased the laptop. If Ubuntu was installed alongside Windows, Windows would ask you what operating system to boot. It would look something like this Windows 7 dual boot


How do I list all package names in a specific category using Terminal?

In terminal  type:

apt-cache search 'web'

It will list all packages in this category and its usage.

Change "web" with the category you want.


Flavour-specific themes, icons, etc., are grouped under the corresponding -artwork package, which in turn may depend on various icon packages, walppaper packages, etc. For Xubuntu, that would be xubuntu-artwork, which depends on:

plymouth-theme-xubuntu-logo
plymouth-theme-xubuntu-text
shimmer-themes
xubuntu-icon-theme
xubuntu-wallpapers

So, you probably need to install xubuntu-icon-theme.


Finally found the answer.
The problem is because of a bug in ettercap!
From the man page:

You can also load a script  without enabling it by appending :0 to the filename

And from the code:

/* enable a loaded filter script? */
uint8_t f_enabled = 0;
/* is there a :0 or :1 appended to the filename? */
if ( (opt_end-optarg >=2) && *(opt_end-2) == ':' ) {
        *(opt_end-2) = '\0';
        f_enabled = !( *(opt_end-1) == '0' );
}

As you can see from the code, and as opposed to what the man page says, you must append ":1" to the filter's file name in order for it to be loaded. Otherwise, the filter is not used.

So why it inly happned to me?
That is beacuse I'm using version 0.7.4.2, which is the version downloaded when I apt-get install ettercap on my Ubuntu. That is opposed to the ettercap website, stating that "The latest Ettercap release is: 0.7.4.1"

A patch that solves the bug was sent to the ettercap developers.


Wireless adapter issues in win10/Ubuntu 16.04 dual boot

I realize your problem may be already solved by now, but since this question shows up in google as a result, i try to suggest how to solve this to help anyone landing here.

I also have a DWA-171 AC 600 Rev.C1.

What you need to do is to head over to this repo and follow the readme to install the correct driver (rtl8821cu) which, according to your usb IDs, is the dongle mentioned in the WikiDevi here. I suggest the use of DKMS, if your system support it.

Hope it helps.


lxc container creation fails with `call to cgmanager_move_pid_abs_sync(blkio) failed: invalid request` (...)

Make sure you do not have ulatency and ulatencyd installed. This can cause the "lxc: call to cgmanager_move_pid_abs_sync(blkio) failed" error.


UbuntuServer, graphics-card died, cant log in to use SSH/VNS

Press Ctrl-Alt-F1 or Ctrl-Alt-F2 to switch to the console mode. Then type in your username and press return. Afterwards enter your password and press enter.
"sudo /etc/init.d/ssh start" should start the ssh server.


Turn off computer every day at same time

you can use this;

open cron file;

sudo -H gedit /etc/crontab

add below end of line

30 21 * * * root shutdown -h now


rectangles instead of fonts in Ubuntu 16.04

Well, after a few unsuccessful attempts I found the solution for my problem:

Manually download Ubuntu fonts from the official website,
Unpack it and open each in Font Viewer (that in my case was automatically by just clicking on each of the file).
On the right corner click INSTALL (do it for all the fonts).
At this point you start to see some fonts.
In my case the problem was with some wrong lines that I put before all that started. So I wrote the next:

  sudo chmod -R 755 /usr/share/fonts/truetype/

  sudo fc-cache -fv

After that everything returned  in the normal way.


Ensure swap encryption, add /var encryption, full HD encryption

You should really ask one question at a time, instead of 3 together.

You can see your swap partitions with:

cat /proc/swaps

And you can see your device-mapper encrypted swap partition configuration with:

cat /etc/crypttab

As long as all of your swap partitions listed in /proc/swaps are also configured for encryption in /etc/crypttab, you're in good shape.

Home Directory Encryption is only meant to protect the data you store in your home directory, and is intended as a balance among security, usability, and performance.  Various bits of system information "leak" (as you say) to /etc (configuration files), /var (varying program information and log files) and /tmp (temporary files).  If you want to encrypt all of that, you should use full disk encryption, which you can configure at installation using the Ubuntu Alternate Install media.


Macbook Pro 8.1 Keyboard Backlight on Ubuntu 11.04 With KDE

Install pommed  and make it start automatically on reboot.


How do I delete Ubuntu installed with Windows system dual-boot?

From the picture it seems you have Windows on the C: (NTFS) partition, as it is labeled "System". Then Windows and Ubuntu are on separate partitions. To delete Ubuntu you just have to format both partitions labeled as "Unknown", and no harm to both your C: and D: partitions will be done.


How can I stop snaps from listing in df?

You can use df's df -x option to exclude certain file systems from the results. Since snaps use the squashfs filesystem, you can define an alias like

alias df='df -x"squashfs"'

to get the non-snap-list as a default.

BTW, see this link for a definition of the snap format.


cdrom line in "Other Software" in "Software & Updates"

Because it IS the CD-ROM or DVD player in your system. If you put one in that has debian install files the system will happily add them to. Ubuntu software centre.

In general keep it disabled. It is unlikely you have a CD or DVD that has debian files.


There's a nautilus script for that:

#!/bin/bash

# Hide-Unhide-In-Nautilus.sh
# Creator: Inameiname
# Date: 21 June 2011
# Version: 1.0
#
#
# This is a simple nautilus script to automatically add file(s)/folder(s)
# to a ".hidden" file so Nautilus will hide them, just like ".*" files
# Instructions:
# - decide what file(s)/folder(s) you want to hide inside a particular folder,
# - highlight them, and right click and select the script
# - it will automatically add the filenames to a created ".hidden" file inside the directory
# - if ".hidden" isn't there, it will add it
# - if you decide to unhide things, simply highlight and select the script again,
# - and it will automatically remove the filenames from the ".hidden" file
# - if ".hidden" contains no filenames, it will remove it
#
#
# Optionals:
# - Add the option to change the owner and group for whatever is selected to hide/unhide
# - Add the option to add the permissions for whatever is selected to hide/unhide
# - Add the option to make executable whatever is selected to hide/unhide
#
#
# Remember this only works inside the current directory/opened folder and files/folders inside that folder.
# Just comment out or uncomment whatever desired.
# Currently, only the ability to hide/unhide stuff is uncommented,
# but you can always just comment it out, and uncomment one of the "Make Executable" commands,
# and/or one of the "Change the owner and/or group of each file" commands,
# and/or one of the "Add permissions" commands, or mix and match whatever you want.
#
#
# For the changes to take effect to the file(s)/folder(s) you hid/unhid, you may have to refresh the folder, or even Nautilus

# Set IFS so that it won't consider spaces as entry separators.
# Without this, spaces in file/folder names can make the loop go wacky.
IFS=$'\n'

# See if the Nautilus environment variable is empty
if [ -z $NAUTILUS_SCRIPT_SELECTED_FILE_PATHS ]; then
    # If it's blank, set it equal to $1
    NAUTILUS_SCRIPT_SELECTED_FILE_PATHS=$1
fi

# Loop through the list (from either Nautilus or the command line)
for ARCHIVE_FULLPATH in $NAUTILUS_SCRIPT_SELECTED_FILE_PATHS; do
    NEWDIRNAME=${ARCHIVE_FULLPATH%.*}
    FILENAME=${ARCHIVE_FULLPATH##*/}
    NAME=${ARCHIVE_FULLPATH##*/.*}

    # Hide/Unhide file(s)/folder(s) using ".hidden" file within the current folder
      # Copies all selected files/folders filenames to ".hidden"
        echo $FILENAME >> .hidden
      # Sorts and Checks ".hidden" for any duplicates
        sort .hidden | uniq -u > .hidden_temp
        rm .hidden
        mv .hidden_temp .hidden
      # Checks ".hidden" to see if there is anything there; if not, it removes it
        for file in .hidden
        do
          if [ `wc -l < $file` -eq 0 ]; then
             # file is empty
             rm $file
          fi
        done
    # Change the owner and/or group of each FILE to OWNER and/or GROUP, if desired
      # chown -R $USER:$USER $ARCHIVE_FULLPATH # set owner:group to current user
      # gnome-terminal -x sudo chown -R root:root $ARCHIVE_FULLPATH # set owner:group to root
      # gnome-terminal -x sudo chown -R $USER:$USER $ARCHIVE_FULLPATH # set owner:group to current user
    # Add permissions, if desired
      # chmod 444 $ARCHIVE_FULLPATH # read-only permissions for all
      # chmod 600 $ARCHIVE_FULLPATH # read/write for you, no permissions for rest
      # chmod 644 $ARCHIVE_FULLPATH # read/write for you, read-only permissions for rest (default)
      # sudo chmod 444 $ARCHIVE_FULLPATH # read-only permissions for all
      # sudo chmod 600 $ARCHIVE_FULLPATH # read/write for you, no permissions for rest
      # sudo chmod 644 $ARCHIVE_FULLPATH # read/write for you, read-only permissions for rest (default)
    # Make executable, if desired
      # chmod +x $ARCHIVE_FULLPATH
      # gnome-terminal -x sudo chmod +x $ARCHIVE_FULLPATH

done

# Add a notification when finished, if desired
    notify-send -t 2000 -i /usr/share/icons/gnome/32x32/status/info.png "Job Finished"

Source: http://gnomefiles.org/content/show.php/Easily+Hide+Files%2BFolders+in+Nautilus?content=142912

Copy and paste the contents of the code box above into a new document. Save it and rename it to Hide or Unhide. Make it executable (right click --> Properties --> Permissions --> Allow executing file as program). Then move the file to ~/.gnome2/nautilus-scripts.

You should now be able to access the script from your nautilus context menu. Just right click on any file(s) you want to hide or unhide and select Scripts --> Hide or Unhide. You will have to reload the folder (F5) to see the changes

The advantage of this method (besides it ease of use) is that it doesn't rename the files.


Editing .desktop file doesn't do anything

I would like to let everyone know how I solved this issue. But first I would like to thank @JacobVlijm for their amazing help. I don't have that much technical skills so I may be butchering the explanation. Please correct me if I am explaining it incorrectly.

So apparently there are 2 google-chrome.desktop files. One is saved in /usr/share/applications and that is the "main one". And one is saved in /home/yourname/.local/share/applications and that is the local one. I changed the main one before and I was told not to do that but rather only change the local one. The second issue was that in the . desktop file there are 3 instances of Exec=/usr/bin/google-chrome-stable. I changed only the last one. In order to fix the issue, I changed all three, and now it works.


How do I install ownCloud client on Ubuntu 12.04?

From 2.2.0 onwards the ownCloud client was not supposed to be build for 12.04 (source), but the last available build for 12.04 is 2.2.1. It is not available on the official download page anymore, but has a separate repository which you can still use to install it.

The installation instructions are on the linked pages, enjoy!


How do you Get the Unity Launcher to Autohide underneath other windows while not autohiding when all Windows are un-maximised?

You can't. You can either let the launcher hide always, or never. "Intellihide" and "dodge windows" are removed from unity since ubuntu 12.10


Try adding these lines to /etc/modules file:

lp
usbserial
option


Problem Allowing Memory With Adobe Flash Player in Firefox

Right click on the game window, and click on Global Settings.

Once the new browser window opens, navigate to  Global Storage Settings panel, and click on it

Choose either options, test them to see which one works for you.

Also you can try doing this.  Right click on the flash game --> settings --> local storage, and set the amount to 10MB, click close.


update manager fails to update - badsig errors displayed in synaptic

Try these commands...

sudo -i
apt-get clean
cd /var/lib/apt
mv lists lists.old
mkdir -p lists/partial
apt-get clean
apt-get update

This will rebuild the cache !


How can I restore control of my computer to the BIOS from grub?

it looks like you have changed the partition id of some of your partitions.

try booting form an ubuntu live cd , get a terminal up and run these commands:

sudo fdisk

<possible password prompt here>

l

this will print a list of filesystems.

use t to change the types (a list of the codes will be printed)

use l to check your changes where ok

use w to write the changes when you are happy with them

then reboot


How do I remove the FGLRX drivers after I've installed them by hand?

Run both this commands:

sudo sh /usr/share/ati/fglrx-uninstall.sh
sudo apt-get remove --purge fglrx fglrx_* fglrx-amdcccle* fglrx-dev*

Plus refer to this site:
 ATI - Ubuntu Oneiric Installation Guide


Windows won't let me install Ubuntu Studio

I think this is because of the partitions. If you have only made 1 partition then there is your issue. You need to make three free space partitions on what ever storage.

The first partition is for Ubuntu and will be 50 Gigabytes (or more) in size.
The second partition is for your home partition and stores configuration files and your personal files such as music, pictures etc.
The third partition is for swap space and is used for intensive operations and suspending the computer.
When you have found the partition with free space, click on it and press the plus symbol (+) under the disk layout.

This website is really helpful. If you have not seen already: http://www.everydaylinuxuser.com/2014/05/install-ubuntu-1404-alongside-windows.html

On that website go the install ubuntu in the bottom middle of the page, and it will show a detailed explanation on installing ubuntu.

If there are any issues please reply or comment.


How to get the terminal keyboard shortcut to open the configured default terminal? (20.10 with GNOME)

powerkey , settings, keyboard, shortcuts, change the existing open terminal ctrl-alt-t to something else, then set a custom shortcut below for your alacrity and set the shortcut key to ctrl-alt-t  (should work but I have not tried it)


Problem installing PCTV triplestick 292e

The problem was that I was using an out of date version of MythTV, for which I can only apologise.

It turns out that was assuming that the error messages were a function of the driver but, by installing the latest version of MythTV 0.27 the messages went away and MythTV was able to scan for channels.

One learning point - Use a scanner such as dvbv5-scan to confirm that the hardware and driver are or are not working.  I did this when I built the system in the first place, but forgot all about it.

One other point to note - the driver appears to load the firmware when the device has been inactive for a while.  The mass messaging about downloading firmware was presumably because MythTV was failing to get the device started properly.  I still get some of these messages, but not nearly as many as I first reported.

I'm sorry to have put something up with such an obviously trivial answer, but thanks to those who looked at the question and gave it some thought.


How to pair android and ubuntu via KDE connect behind firewall [ufw]?

Just found a solution

https://community.kde.org/KDEConnect mentions that we need to enable rule in ufw.

so...

sudo ufw allow 1714:1764/udp
sudo ufw allow 1714:1764/tcp

And I needed to reboot my laptop for things to work.
Its working now like a charm with ufw running.


Openconnect won't disconnect in Ubuntu 17.10

If you called openconnect in the foreground then Ctrl+C interrupts the process and closes the connection. In case you started VPN in the background under the userx then you can call kill of pkill from the same userx or from the root (use sudo).
If you could not kill the process then either you had insufficient rights to do it or just misprinted the name. To check whether the process still exists use $ ps -A | grep openconnect.


For the perpetual shutdown problem, unplug any usb devices when the computer is booting or shutting down. I've been pretty lazy lately so I only know the workarounds and not the voodoo behind them, but it keeps my laptop from hanging up.

For your issue resuming from sleep, see if you can drop to a console with ctrl + alt + F2  when it hangs up, and then switch right back to tty7 with ctrl + alt + F7

Saw this thread on the side of the page and its got some more ideas to try.
Good Luck!


Problem in installing mysql2 in ubuntu 14.04 in virtual box

You need to install a few mandatory packages for gem to work. Should be ...

sudo apt-get install libmysql-ruby libmysqlclient-dev

and after that

sudo gem install mysql2

will work.

Source.


A new task manager plasmoid, Icon Tasks has some nice features that including Unity API support.

http://kde-apps.org/content/show.php/Icon+Tasks?content=144808


How to poll a variable while executing a script?

#!/bin/bash

while read var                 # read variable in specified file (0 or 1)
do
if  [ "$var" -eq "0" ] ; then  # if variable is 0 throw error message
    echo "error"
fi

echo "What is your name?";
read name </dev/tty;
echo "You entered: $name"; sleep 2;

done </path_to_file/file        # specified path to file
exit                            # end of script, exit


How to (quickly) switch to dark mode in Ubuntu with GNOME and to make it fully dark?

For easy and quick toggling from Dark to Light theme and vice versa install this GNOME extension:

Night Theme Switcher - Extensions GNOME Shell, it has a lot of settings options incl. automated switch based on time.

Invert the color of individual windows only (Default shortcut is Super+I): use the Globe Extension Invert Window Color.
Thank you Sam!
Ubuntu 20.04: You can now easily choose a dark mode within the Settings: Appearance > Window colors > Dark. There is no possibility to set a time to have an automatic switch based on time, though (without a GNOME extension, see above).
For a Full Dark Mode of the system (incl. System tray menu, top-bar calendar, notification popups, and desktop context menu) you need some more steps:

Install GNOME Tweaks and other tools if you don't have them, then reboot/restart. In a terminal:

    sudo apt install -y chrome-gnome-shell # Works with Firefox*, too.
    sudo apt install -y gnome-shell-extensions
    sudo apt install -y gnome-tweak-tool

(*) Firefox add-on for GNOME Shell integration in Firefox.
2. Install user themes GNOME Shell extension:
https://extensions.gnome.org/extension/19/user-themes/
3. Turn on user themes GNOME extension in GNOME Tweaks or in the GNOME extensions app.
4. Log out and back in to your session OR manually restart GNOME Shell (Alt + F2, type r, hit enter) for the theming extension to actually be activated.
5. Launch GNOME Tweaks and navigate to Appearance in the left pane, choose Yaru-dark as the Shell theme!
More details and source: [How to Enable Dark Gnome Shell Menus, Calendar in Ubuntu 20.04 | UbuntuHandbook]
But the Dark Theme Toggle does not make some of the apps fully dark and you have to do some further configuration:
LibreOffice: (adapted from Debugpoint.com)

Open LibreOffice. Open any component – Writer, Calc etc.
From menu, click Tools -> Options.
Go to Application Colours, select document background as Black. You can also choose the Application background as Black.
There may be more custom color settings you like to adapt. For example, Remove the gray background from Table Of Contents: Modify the color setting in Text Document, ☑ Index and table shadings.
(Or disable it: ☐ Index and table shadings.)
Some special formatting, e.g. links were not shown well on my computer, I chose a lighter colour for the unvisited and visited links.
If you would like to change to a dark icon theme, change it from "View" options on the left side for better visibility of the toolbar icons, e.g. choose "Breeze (dark) as icon style.

There is a also a dark theme to install: RaitaroH/LibreOffice-BreezeDark: Icons, color palette and color scheme for LibreOffice
Firefox:
Enable Dark Mode in Firefox, see HowToGeek for details.

Click menu > Add-ons > Themes, choose Dark theme.

To view the webpages in dark colours, use an add-on. Two tested options:

Dark Reader:

Handy keyboard short-cut to toggle: Shift-Alt-D
It promises that "it does not show ads and doesn't send user's data anywhere. It is fully open-source."
It may cause more CPU use, though.

Dark Background and Light Text
Before you install disable similar extensions.
Handy keyboard short-cut to toggle: F9

PDF viewer (e.g. Evince document viewer): See Is there any pdf viewer with dark mode? - Ask Ubuntu
Go to the options on the top right corner (Sandwich menu).
Then select Night Mode or Inverted colours.
Wire messenger (How to install Wire messenger on Ubuntu):
Go to preferences, then Options, choose dark theme.
Thunderbird
With TB 78+ you can choose a dark theme (open add-on page and choose themes on the left side).
Apart from that there are some dark theme add-ons with more tweaks.
Audacity:
The theme to use can be selected at Edit > Preferences > Interface
You can also change the colour of the waves without selecting a theme.
And more sophisticated (source: OMG!Ubuntu):

Download the Audacity Clean Dark Theme pack
Extract the .zip
Copy ImageCache.png from the named colour folder you want
Paste file into ~.audacity-data/Theme (if the directory doesn’t exist, create it)
Open Audacity > Preferences > Interface
Select ‘Custom’ theme option

Calibre: See How do I get a dark theme/night mode in Calibre? - Ask Ubuntu


Yes, it'll work.
First, your CPU speed is not 1.3GHz. Well, it may be at that speed right now, but the CPU has a max frequency of 3.9GHz. The max, not the minimum is what the rating cares about.
It's a fairly new, capable, Intel CPU, from their top line. It'll run any software meant for normal desktop computers without big problems.
So go ahead, install Ubuntu 20.04. Your system is plenty good enough to handle it.
If you want to verify before installing, try a Live medium. You can install it right from the live environment if you like what you see.


Can you get live wallpapers on Ubuntu 14.04?

Yes we can ..follow the steps:

Add PPA for live wallpaper

sudo add-apt-repository ppa:fyrmir/livewallpaper-daily

Install livewallpaper

sudo apt-get update && sudo apt-get install livewallpaper

Install livewallpaper-config and livewallpaper-indicator

sudo apt-get install livewallpaper-config livewallpaper-indicator

All done. Now type live wallpaper in dash:

And select wallpaper of your choice like this. Trust me its moving :p


VMWare Workstation 9 - Share VMs on different disk location

I found the answer lately while messing around with Ubuntu. It seams like we're able to bind existing folders to other area of the file system and thus, trick VMware Workstation to think that all virtual machines are in the same location.

Here's the step by step to solve the problem:

1- Take a look at the shared directory location already configured. To do this, open VMware Workstation -> Edit -> Preferences, then click on the "Shared VMs" menu at the left. Adjust all settings to your needs.

2- Before closing VMware Workstation, remove all virtual machines from your library (DO NOT DELETE FROM DISK, just remove from library, you will understand later). Close VMware Workstation, then, open a terminal and edit /etc/fstab.

3- Add lines like these:

/HDDs/sdb2/vm1   /home/name/VMs-Shared/vm1       ext4    bind    0       0
/HDDs/sdb2/vm2   /home/name/VMs-Shared/vm2       ext4    bind    0       0
/HDDs/sdc1/vm3   /home/name/VMs-Shared/vm3       ext4    bind    0       0

4- Restart your system or use the following command line:

sudo mount --bind -a

Please be advice I'm not sure if this is working, I haven't tested this command for a long time. If you're not sure, just restart the system.

5- Open VMware Workstation and open all virtual machines from the Shared location (VERY IMPORTANT). Since all VMs are open in the proper location, you just need to right click on a virtual machine -> Manage -> Share. A wizard will open, just click Next and Workstation should tells you it's already ready to be shared (no move operation needed or anything else like this).

From on now, enjoy features related to the "sharing" system. You'll be capable to auto start VMs on host startup and manage then remotely.

Hope it helps!

Dave


Instructions

Go to "Start menu → Preferences → LXQt settings → Locale". (Or just start lxqt-config-locale)

Under "Region:", select the upmost entry "No change".

Click "Close" and confirm to save the new settings.

Go to "Start menu → Preferences → LXQt settings → Session Settings" (or just start lxqt-config-locale) and in section "Environment (Advanced)" make sure that no locale-related environment variables are set here: LANG, LANGUAGE and any LC_* variables.

Result
Your ~/.config/lxqt/lxqt-config-locale.conf will now look like this, omitting any locale setting there at all:
[General]
__userfile__=false

Together with not overwriting locale-related environment variables in the session, this means that the system-wide settings from /etc/default/locale will now be taken over by LXQt.
Details: a LXQt UI quirk
You can ignore the fact that, at the next start of lxqt-config-locale, your "Region: No change" value will be replaced with the system-wide locale value. This should be considered as a bug in LXQt in initializing this dialog. But as long as you don't save that dialog's values again, ~/.config/lxqt/lxqt-config-locale.conf will still not overwrite the system-wide locale value.


Two accounts on same computer - how can I make a share folder for both?

Here's a tutorial from Ubuntu Forums: How to create a shared folder for multiple local users.

  Install bindfs.

sudo apt-get install bindfs

  Create a hidden and a visible directory for the files.

sudo mkdir /home/.media # create a hidden directory
sudo mkdir /home/media

  Create a new group.

sudo groupadd media

  Add the user(s) to the group.

sudo gpasswd -a usrname media

  Repeat this for all users. Log out and log back in your current user.
  Edit the fstab file.

sudoedit /etc/fstab

  Add a new entry at the end of the file.

bindfs#/home/.media    /home/media    fuse    group=media,perms=g=rwx

  Mount the filesystems mentioned in fstab.

sudo mount -a

  Move the files you want to share in the /home/media directory.


Wanting to make magnet urls open with qBittorrent in Chrome

As of now, the new way of doing it is:

gio mime x-scheme-handler/magnet qbittorrent.desktop


How to grow LVM partition to include newly released partition (now unallocated space)

You need to:

Use fdisk/parted/etc. to create a partition in the currently empty space
Use pvcreate to create a physical volume on the new partition.
Use vgextend to add the new physical volume to you current volume group, or vgcreate create a new volume group
Use lvextend to extend the logical volume of /home (with -r, so that the filesystem gets extended too). You'll want to unmount the partition before doing this.

You can do both 1 and 2 in a single step using GParted (right click free space, format as lvm2 pv). The third and fourth step needs to be run using the respective commands.


General rules for converting GRUB entries to GRUB 2?

General rules for GRUB to GRUB2 conversion:

First, the root hard drive partition needs to be specified along with the partition type:

insmod ext2

set root='(hd0,msdos8)'

Then, the kernel is specified.  In GRUB, this was kernel.  In GRUB2, it's linux:

linux   /boot/grub/memdisk.bin (additional options can go here, such as a "set root" option for modern linux)

Then, the initial ramdisk is specified, which looks exactly the same as in legacy GRUB:

initrd  /boot/grub/sbootmgr.dsk


you can create a DEB from .jar file.

You have to add following code to your pom.xml file

<build>
    <groupId>org.test</groupId>
    <artifactId>some-lib</artifactId>
    <version>1.0</version>
    <plugins>
      ...
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>deb-maven-plugin</artifactId>
        <configuration>
          <description>A test project</description>
              <maintainer>Tim OBrien &lt;tobrien@discursive.com&gt;</maintainer>

libs

              <priority>optional</priority>
              <architecture>all</architecture>
        </configuration>
        <executions>
          <execution>
            <goals>
              <goal>deb</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      ...
    </plugins>
  </build>

and after that running

mvn package

will gives your a .DEB file.

For more information you must read this : http://mojo.codehaus.org/deb-maven-plugin/using-deb.html


Tooltips/Labels in Cisco packet tracer are empty

I have the same issue, and I'm running Ubuntu MATE 16.04. Curiously, the tooltip text is present, yet it's nearly illegible due to it being colored white. I attempted to change the color of the text via Ubuntu MATE's "Appearance Settings" but this had no effect. I checked the Cisco NetAcademy  Bugzilla and it appears that this issue was reported in bug 19971 back on September 16, 2016. After browsing through the comments, I noticed that PacketTracer uses Qt. That led me to my resolution:

I closed my PacketTracer (saved my work first, of course) and went to the Menu - Qt 4 Settings. When you click on it, it will open a window called "Qt Settings"
On the tab titled "Appearance" I took a look a the "GUI Settings" section.
In the "GUI Settings" you will find a pulldown menu. My settings were set to "GTK+"
Change the option to "Desktop Settings (Default)"
Locate the "File" menu option at the top of the Qt Configuration window, click it, and press "Save"
Close the "Qt Settings" window.
Open up PacketTracer and check and see if you can see the tooltips. If not, you may need to go back into the Qt 4 Settings and change the colors manually.


Minimal?  Depending on how minimal we're talking, this'd work (I'm including SSH as being needed in this though):

iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -A INPUT -p udp --dport 80 -j ACCEPT
iptables -A INPUT -j REJECT --reject-with icmp-host-unreachable

If you want to add other ports or services to be internet facing, those ports can be opened with iptables -I INPUT [numberOfRules] -p [protocol] --dport [port or port:range] -j ACCEPT, where [numberOfRules] is the number of the rule which has the REJECT target, [protocol] is the protocol (TCP, UDP, etc.), and [port or port:range] is either a single port or a range of ports defined with start:end.  Using comma separation also seems to work there.


Right-click on the .jar file. Select' Properties'. Then on the middle tab, tick the box that says Allow execution. Then double click the .jar file to execute it.


There should be a space beetween /home/bubba/Desktop/tsp_art_tools_0_8_1/tspart.py/home/bubba/Desktop/tsp_art_tools_0_8_1/baby04.pbm

So, it should be like this

/home/bubba/Desktop/tsp_art_tools_0_8_1/tspart.py  /home/bubba/Desktop/tsp_art_tools_0_8_1/baby04.pbm


Why does Ubuntu CD contain a "pics" folder with Debian-related images?

These files are part of the debian-cd package, which is used to build the Ubuntu live CDs.

The images are sourced by an include file named README.html.in, which the add-bin-doc tool incorporates into README.html at the root of the CD's filesystem. This file is either never generated or is deleted from Ubuntu's CDs, so I believe the images are unused.


Installing Ubuntu 13.10 on new Macbook Pro. Installs then fails after restart

I don't believe Macs are able to use Ubuntu natively. I think you need a third-party bootloader such as rEFInd. Although if you still have Mac OS X installed I seriously recommend you use this tool: Mac linux USB loader


That's difficult, as routers normally want to install their software on connected computers, to enable priting via USB-Port. This fails, because probably it is a Windows Driver. Some time ago I also tried it and gave up finally.
Better would be, if possible, to connect your printer with a LAN-Cable to the router. Or you can connect the printer via USB to a computer and share it over the network. Thats easy, just go to System preferences - Printers - Add printer - On the network - Search. Connected printers should be found.


no shutdown, no boot after latest SW update Kubuntu 18.04

Obviously the failure has been fixed with a later update release. I've been waiting four weeks without touching the version (only security update for firefox installed). Then I simply tried again to install all 285 updates. Everything still works ok after.


By default, what system messages get mailed to root?

By default, cron will mail all output from cron jobs to the owner of the job, whether they fail or not.  (Root is the owner of the system cron job, and is configured as the mail destination for non-root daemon cron jobs.)  Most system cron jobs are carefully written not to produce output unless something is wrong.

Any other program can send mail to root, but not many will in a default Ubuntu install.  Things I have seen include

in Debian, some programs will send mail when they are not properly configured, but I have not seen this recently in Ubuntu
mdraid sends mail when an array fails or is restored
apcupsd sends mail when the machine loses AC power
uptimed sends mail when you pass a milestone or record

If you're writing your own cron jobs you can set MAILTO to control where the output is sent.  (See also man 5 crontab.)


It sounds like you encrypted your home folder. Authentication with ssh is not enough to decrypt your home folder (the .ssh is encrypted with your home folder). You must authenticate at console to decrypt the folder first. Alternatives are to decrypt your home folder, or to change sshd_config such that it does not need to read from your encrypted home folder.


Cannot create a private key with seahorse

It looks like this may be a bug in Seahorse, as I just tried to generate an RSA private key on Xubuntu 18.04, and encountered the same issue.

You can instead generate the RSA private key using the command-line:

openssl genrsa 4096

You should then be able to import this into Seahorse if you need to.


Thanks to the kindness of a developer, I can give some information to my questions.

It should be available soon (launch a dialog).

Best regards!


How can I set up a filter in Synaptic that finds all packages not installed from official repositories?

It's actually not as hard as I thought it might be - and it's probably quite a valuable filter to have!

First you select which status you want to show. I selected "Installed" amongst a couple of others but that's probably all you need.

The real nuts and bolts come from the properties screen. In there you can set the origin requirements. All I did was exclude anything from archive.ubuntu.com (which is the mirror I use). If you're using another mirror, change that string.

The alternative would be to disable all the PPAs in sources and then look at the local section.


How can i hear in my headphones what comes through the line-in?

If your sound card supports it, you could probably do it by fiddling with the sound settings. You normally don't get into that level of control using the default volume control utility in Ubuntu, but you can run a text mode utility called alsamixer. If you find the your line input, you could locate (in the playback tab, not the capture tab) your line input. In the capture tab you can set the level of the input, but whether you can hear the input in your headphones, depends on the playback tab.

If you have multiple sound cards (or USB headphones), you might need to let alsamixer know which sound card you want to control, e.g.

alsamixer -c 0

or

alsamixer -c 1

...and so forth.

Note that this will only work within one physical soundcard; it will not work with e.g. a sound card and USB headphones, which are a separate sound card from the operating system perspective.

An alternative could be a low latency audio server, Jack Audio Connection Kit. It induces more latency than the hardware solution described above, but gives you more control. For just playing with a backing track, fiddling with alsamixer is sufficient.


Postgrey - how to add sending server to whitelist to disable greylisting

You performed the right steps, adding to whitelist_clients. It is better to create a new file whitelist_clients.local, which is not modified while upgrading the postgrey package and is also read by postgrey. Then, restart postgrey.

But, due to a bug in the Debian postgrey init script, postgrey is not actually being restarted by running service postgrey restart (even stopping it is broken). Either restart the whole machine, or kill the postgrey process manually and start it again (using service postgrey start).

The issue is told to be fixed in June 2014 and restart is hopefully working in future Debian/Ubuntu releases.


Create Encrypted Bootable USB without Overwriting Internal Disk

Encrypted 20.04 Full Install USB using a Virtual Machine
Introduction
Another way of doing this would be to unplug/remove the internal drives or disable them in the UEFI. This is not always possible or convenient. I did this using a QEMU-KVM virtual machine. If you already have the QEMU-KVM virtual machine setup on your Ubuntu desktop or if you have a computer running Ubuntu that is capable of running QEMU-KVM virtual machines, then this approach may be easier than unplugging hard drives from inside of your computer.
In general a virtual machine (VM) is great for managing full installs of Ubuntu in USB. Once I set it up, I can boot the USB full install in the VM and maintain it without shutting down my main Ubuntu desktop.
Prerequisites

QEMU-KVM Virtual Machine Manager GUI running on Ubuntu 20.04.

The following command will install the all the packages needed:
sudo apt install --install-recommends virt-manager

An empty USB drive large enough for a full installation of Ubuntu
and sufficient space to keep your data
The Ubuntu 20.04 ISO stored in the computer where the QEMU-KVM is
running

Find USB device name
We need to find the device name of the USB drive. Insert the USB drive and open the Gnome Disks app:

Note, my USB drive is called /dev/sdc. Yours may be different. You will need this information in the next step.
Unmount any and all partitions using the black square button and turning it into a black triangles.
It is important unmount all the USB partitions of the USB.
The process of installing Ubuntu in the VM will require the VM to have full access to the USB drive, so that it can overwrite and create new partitions in the VM.
Create a new VM to use USB drives
Normally when you create a new VM it prompts you to create a virtual hard disk (a file) where the OS is installed. We want to directly access the USB and install Ubuntu there. This requires a new VM setup. We also want create a VM that boots Legacy BIOS and optionally another VM that boots UEFI.
Open the app Virtual Machine Manager and go to File > New Virtual Machine:

We will use the Ubuntu 20.04.2.0 Desktop ISO. click Forward and proceed to the next screen:

Click the browse button and find the ISO file. Then click Choose Volume to select it. Fill in the Name of the OS you are installing as seen above.
Select the amount of RAM and the number of CPUs you want to allocate to this VM:

Now comes the important part. click on Select or create custom storage and type in your USB device name:

Note, mine is /dev/sdc, yours may be different. If you have done this before, you will get a warning Disk "/dev/sdc" is already in use by other guests.... Click Yes to use this disks.
Edit the name of the VM if you want.
Select Customize configuration before install:

This is where you choose BIOS or UEFI mode:

Unlike the real computers, it is hard to switch between BIOS and UEFI modes in the QEMU-KVM VMs. It can be set to boot either of the two modes at the time of VM creation.
If you only want the USB to use only in computers that have UEFI, then select UEFI.
If you only want the USB to use in computers that have UEFI or BIOS, then select BIOS.
If you select BIOS, at the end of the installation the USB will be bootable only in old computers with BIOS or or new computers in the Legacy BIOS mode.
See the link at the end of the answer for how to modify the USB created in the BIOS mode to boot both in BIOS and in UEFI mode.
Select BIOS if not already selected.
If you want to create another VM to test UEFI booting of the USB you are creating, follow all the steps above and select the UEFI option for the second VM.
Click the Apply button at the bottom to make the changes.
When satisfied with all the changes, click Begin Installation at the top to continue. This will start the newly created VM and boot from the ISO you selected in the BIOS mode. You should see this screen:

If you get a different screen you may have booted using the UEFI mode. Next you will get a screen that says Try Ubuntu without installing:

Select the Try Ubuntu option. This will let you do the changes we need after the installation. You will see the familiar Ubuntu Desktop with the icon for Install Ubuntu.

Select Language, Keyboard, Normal Installation, Install third Party... .
At Installation type Tag "Erase disk and install Ubuntu" and then select "Advanced features". Click "Use LVM with the new Ubuntu installation" and then "Encrypt the new Ubuntu installation for security".

Choose a security key. Overwrite empty disk space if inclined.
Select Country, then User name and Password.
When Installation completes you will have a USB with encrypted full instillation of Ubuntu that boots in the mode you selected at the time of the VM creation.
For some reason I get a black screen instead of the encryption pass-phrase prompt when I boot the USB using a VM. However, blindly typing the pass-phrase and hitting Enter works.
If you want to create a USB that boots in both BIOS and UEFI modes, or works with both old computers with BIOS and newer ones with UEFI, then see How to Make BIOS/UEFI Flash Drive with Full Disk Encryption
Hope this helps


How to switch from Linux Ubuntu to windows 8.1

It's very easy!

1) Boot your Windows install DVD

2) Progress though the screens until you see "Setup is starting". Wait till you land on the next screen.

3) At that point do not continue further in the installation screens until doing steps 4-6

4) Press SHIFT+F10

5) In the CMD Window, type the following:

diskpart
list disk
select disk 0 #Replace the "0" accordingly
clean
exit
exit

6) Continue on with the install. You disk has been wiped!


Brother MFC-L2700DW printer does not work

Ironically a friend of more than 20 years emailed me today with the same question about a similar model of Brother Printer, and I can vouch that he is using version 12.04LTS, because I'm the one who installed it for him.  I was able to save considerable typing by merely editing my reply to suit your model of Brother printer:

Driver installation tutorial for Brother MFC-L2700DW

Open this link.
http://support.brother.com/g/b/downloadtop.aspx?c=eu_ot&lang=en&prod=mfcl2700dw_us_eu_as
Be sure to check (DEB not RPM).  Ubuntu is Debian based, so downloading the RPM version will only lead to frustration.
With Linux and linux(deb) checked, press SEARCH.
The following page lists several choices, the first  one being the most comprehensive.
I recommend you download that first choice, the driver installer, and open it as soon as it has downloaded.  Doing so will open your Ubuntu Software Center and complete the software installation.

It should work immediately without rebooting, but in case of difficulty, reboot.


Need a shell script to find the latest file from a directory and move it to another on a weekly basis

Create a script with something like this;

#!/bin/sh
mv "$(ls -t <name of your file> | head -1)" /directory/it/has/to/go
find /directory/it/has/to/go -type f -mtime 90 -exec rm {} +

Now we have to create a cronjob so this script runs every week.

$: crontab -e

Add this line:

0 0 * * 0 yourscript.sh >/dev/null 2>&1


differences between ubuntu touch and ubuntu-touch-preview

Ubuntu Touch

http://cdimage.ubuntu.com/ubuntu-touch/daily-preinstalled/current/

ubuntu-touch: is the to be final system, the main element of this build is that it is a flipped image, that is an Ubuntu boot.img that boots straight into Ubuntu and then loads android in an lxc container.

The Ubuntu part of this image is build directly on cdimage and the android part aims to be as well.

Ubuntu Touch Preview

http://cdimage.ubuntu.com/ubuntu-touch-preview/daily-preinstalled/current/

This is the build that is now considered legacy, it is build entirely on Jenkins infrastructure and pulled into cdimage for public consumption.

This image is also the unflipped version, that is an Android boot.img that boots into Android and starts Ubuntu in a new pid namespaced chroot.

File description

First some generic conventions:

[device] can be any of mako (Nexus 4), maguro (Galaxy Nexus), grouper (Nexus 7 Wifi) or manta (Nexus 10).
[series] can be any of saucy, raring or quantal (and any other series after saucy)

So given the former, this is the file description:

[series]-preinstalled-boot-armel+[device].img corresponds to the boot image partition for Android devices which is the Linux kernel plus an Android ramdisk. Used in unflipped images.
[series]-preinstalled-boot-armhf+[device].img corresponds to the boot image partition for Android devices which is the Linux kernel plus an Ubuntu ramdisk. Used in flipped images.
[series]-preinstalled-recovery-armel+[device].img corresponds to the recovery image partition for Android devices which is a small system from where primarily update zips can be deployed. For the saucy timeline an Ubuntu specific way to perform updates is being setup.
[series]-preinstalled-system-armel+[device].img corresponds to the system image partition for Android devices which could be simplified as the Android user space part of the OS.
[series]-preinstalled-armel+[device].zip this is the update zip for unflipped images, it is basically the Android boot.img plus the system.img
[series]-preinstalled-touch-armel+[device].zip this is the update zip for flipped images, it is basically the Ubuntu boot.img plus the system.img
[series]-preinstalled-phablet-armhf.zip This is the Ubuntu OS itself for unflipped legacy images, it is device agnostic.
[series]-preinstalled-touch-armhf.zip This is the Ubuntu OS itself for flipped images, it is device agnostic.


custom Ubuntu 20.04 Minimal installation on Virtualbox with Qtile - unexpected GUI

The packaging for xinit has changed between 18.04 and 20.04.
If you apt install xinit on a bare Ubuntu 18.04 system, you'll get:
0 upgraded, 244 newly installed, 0 to remove and 11 not upgraded.
Need to get 84.1 MB of archives.
After this operation, 551 MB of additional disk space will be used.

On a bare Ubuntu 20.04 system, installing xinit alone pulls in a lot more:
0 upgraded, 513 newly installed, 0 to remove and 23 not upgraded.
Need to get 172 MB of archives.
After this operation, 951 MB of additional disk space will be used.

That'll be why you're seeing more things installed, and a different behaviour.


Simply changing Hardware decoding from VDPAU video decoder to VA-API video decoder via X11 in Input / Codecs > Video Codec > FFmpeg solves the problem.


PCIe bus error severity=corrected id=00e5

Try this steps:

cp /etc/default/grub ~/Desktop
Edit grub. Add pci=noaer at the end of GRUB_CMDLINE_LINUX_DEFAULT. Line will be like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pci=noaer"
sudo cp ~/Desktop/grub /etc/default/
sudo update-grub
Reboot now

:) Enjoy.


How to prevent additional distros from installing their own GRUB boot loader

Not being a multi-distro user for a number of years and,  if I remember correctly.

What happens is that the 2nd distro (and later ones) only ADDS information to the existing GRUB file and does not replace the file itself.

Again,  IF,  I repeat IF,  I remember correctly,  GRUB assums that the last distro knstalled is the primary version and places it in the first position for booting unattended.

While GRUB can be edited,  I found it simpler to press the boot menu key while startingvand selectingvthe OS that I wanted from the boot menu when it appeared.