Why does tmux/byobu fill my screen with garbage characters when I copy a selection?

There is an option set-clipboard that will try to copy your selection to the x-clipboard with an escape sequence.

:set-option -s set-clipboard off

gnome-terminal does not support this method of using the clipboard, which is the default terminal in Ubuntu.


Having to chmod my samba shares to 0777 feels wrong just to get them to be writeable. Is this really necessary?

The solution ended up being to add force user = www-data


Snap install of IDEA updated automatically to EAP

You can change the installation of your snap application from the --edge or newest version to the --stable version by running the following:

sudo snap refresh intellij-idea-community --stable --classic

If you want to go back to the bleeding edge version, run it as:

sudo snap refresh intellij-idea-community --edge --classic

Or you can also run it in beta as well:

sudo snap refresh intellij-idea-community --beta --classic

If you want to see all the versions that are available to be installed or switch to use snap info

Example:

~$ snap info intellij-idea-community
name:      intellij-idea-community
summary:   Capable & Ergonomic Java IDE
publisher: jetbrains✓
contact:   https://www.jetbrains.com/idea/documentation/
license:   unset
description: |
  IntelliJ IDEA Community Edition is a free and open-source edition of
  IntelliJ IDEA, the commercial Java IDE by JetBrains. IntelliJ IDEA
  Community Edition provides all the tools you need for Java, Groovy, Kotlin,
  Scala, and Android. It offers instant and clever code completion,
  on-the-fly code analysis, and reliable refactoring tools. Mission-critical
  tools such as integrated version controls systems and a wide variety of
  supported languages and frameworks are at hand — no plugin hustle included.
commands:
  - intellij-idea-community
snap-id:      KSPcSedMkvhgEjkg3Ki1PdjX2Ylm2aOy
tracking:     stable
refresh-date: today at 08:17 MDT
channels:
  stable:           2018.2.4     (83) 481MB classic
  candidate:        2018.2.4     (83) 481MB classic
  beta:             2018.2.4     (83) 481MB classic
  edge:             2018.3-EAP   (87) 500MB classic
  2018.3/stable:    –
  2018.3/candidate: –
  2018.3/beta:      –
  2018.3/edge:      2018.3-EAP   (87) 500MB classic
  2018.2/stable:    2018.2.4     (83) 481MB classic
  2018.2/candidate: 2018.2.4     (83) 481MB classic
  2018.2/beta:      2018.2.4     (83) 481MB classic
  2018.2/edge:      2018.2.5-EAP (86) 481MB classic
  2018.1/stable:    2018.1.6     (65) 495MB classic
  2018.1/candidate: ↑
  2018.1/beta:      ↑
  2018.1/edge:      ↑
  2017.3/stable:    2017.3.5     (36) 425MB classic
  2017.3/candidate: ↑
  2017.3/beta:      ↑
  2017.3/edge:      ↑
installed:          2018.2.4     (83) 481MB classic

Hope this helps!


You can do that through safe mode, just need to mount the partition in read-write mode with this command : mount -o remount,rw /. This command is necessary  because in recovery mode the Ubuntu portion of hard drive is mounted in read-only mode and you cannot make changes to files.  rw option tells ubuntu to allow read-write access to Ubuntu part of the disk. And yes, it is needed before running vim /home/yourusername/.bashrc.

You can get to safe mode aka recovery mode, by selecting "Advanced Options for Ubuntu" in the boot menu, then recovery mode (if you have multiple ones there, don't freak out - any of them is OK). Then access the root shell, and run the command I mentioned above. After that you can proceed with editing .bashrc or .profile with a text editor such as nano or vi

Notice also, that in recovery mode, you don't need sudo as in recovery mode you automatically logged in as root. You will also need to navigate to your nome directory to edit .bashrc or .profile by running cd /home/yourusername Notice that if you are logged in as root sudo ~/.bashrc is for root's .bashrc. Tilde expands to current users' home directory, and if you are logged in as root, it will expand to root's home directory. This is why you need to run vi /home/yourusername/.bashrc


The package you need to install is named libxft-dev: sudo apt-get -y install libxft-dev


Steps are as follows :

go to https://www.minecraft.net and log into your account.
then click on the minecraft dirt cube that says download.
then click on the big green button that says "DOWNLOAD FOR YOUR DISTRIBUTION"
then scroll down a tiny bit and click on ".deb package" in the middle of the paragraph that says "DEBIAN AND DEBIAN BASED DISTRIBUTIONS".
if you're using chrome have the download open with default as soon as it finishes downloading, otherwise run when downloading completes.
I should open the software center. click "install"
hit the windows/super key on your keyboard and type "Mine..." Minecraft will show up. once again log in an click "play latest..." it will download and run minecraft.

(minecraft on linux is 64 bit only)


Please get a temporary internet connection by ethernet or any other means. Open a terminal and do:

sudo apt-get update
sudo apt-get install firmware-b43-installer
sudo apt-get install firmware-b43legacy-installer

Detach the ethernet or other connection, reboot and your wireless should be working.


Nope, -j does not mean MHz it specifies how many compile processes should be startet in parallel. So you should put the number of cores available for this option or maybe number of core + 1.

Depending on the compile task, it can be that there is a lot disk IO which would slow down the complete compile process when a too high -j as it would put much more IO on your storage system.


"could not add sta to kernel driver" hostapd - not able to connect more then 10 clients

Seems like this was the default limit on the card. It supports max 10-12 devices with some tweaking around channel=11 .

To connect more number of devices we need to look in for alternative wireless card .


How do I make database of files and folders existing on an external hard drive?

If you just want a list of files, you can use a simple find, like @Raffa commented.
find /PATH/TO/EXTERNAL/HDD/ -type f -follow > "/PATH/TO/SAVE/file_list.txt"

If you want to save metadata information of your multimedia files, you can use mediainfo, that reads information for audio, video and picture files:
find /PATH/TO/EXTERNAL/HDD/ -type f -follow \
  -exec mediainfo -f --Output=XML + > "/PATH/TO/SAVE/file_list.xml"

You can then read the output with any regular xml parser, e.g. xmlstarlet:
xmlstarlet sel -t -v '/Mediainfo/File/track/Complete_name' -n "/PATH/TO/SAVE/file_list.xml"

or e.g. search only images:
xmlstarlet sel -t \
  -v '/Mediainfo/File/track[@type="Image"]/../track/Complete_name' \
  -n \
  "/PATH/TO/SAVE/file_list.xml"

or find all images with file size > 1MB:
xmlstarlet sel -t \
  -v '/Mediainfo/File/track[@type="Image"]/../track[@type="General"][File_size[1] > 1048576]/Complete_name' \
  -n \
  "/PATH/TO/SAVE/file_list.xml"

Installation:
sudo apt install mediainfo
sudo apt install xmlstarlet


Ubuntu GNOME 16.10 screen orientation spontaneously changes

You can lock the rotation of the screen using the second icon in the top-right menu. The icon looks similar to the icon used for screen rotation in mobile OSes like Android.

In order to disable the functionality permanently (desirable if you do not have a touchscreen :-) ), you can do that by setting dconf-key active in org.gnome.settings-daemon.plugins.orientation to false using either gsettings (CLI) or dconf-editor (GUI).

gsettings set org.gnome.settings-daemon.plugins.orientation active false

In later versions

gsettings set org.gnome.settings-daemon.peripherals.touchscreen orientation-lock true

After logging out and in again, the the button should no longer be there and your screen's orientation should stay as it is.


Try:

 sudo rm /var/cache/apt/archives/thunderbird_12.0.1+build1-0ubuntu0.12.04.1_i386.deb
 sudo apt-get clean
 sudo apt-get update && sudo apt-get dist-upgrade

Note:
Just look at the output of apt-get dist-upgrade before agreeing, it should be safe on a system without -proposed enabled


Overriding only Option Rotate for a specific Monitor while keeping other auto configuration values

Okay, after googling around, I found a way to minimalistically augment the Xorg auto-configuration (at least for Monitor section).
/usr/share/X11/xorg.conf.d/00-hdmi-1-default-rotation.conf:
Section "Monitor"
    Identifier "HDMI-1" # Use the one reported by xrandr
    Option "Rotate" "inverted"
EndSection

I noticed in Xorg.0.log that this one got picked up, and yay First problem & Third problem can be solved in this way!
As for the Second problem: xrandr --auto seems to use information provided from hardware, and ignores the defaults set by the software.
So, the conclusion is, this can't be done as there is no way to solve second problem posed in question.


It MIGHT be screensaver related. If you run XBMC from Gnome (or similar), you can try (for 11.10):

gconftool-2 -s /apps/gnome-screensaver/idle_activation_enabled --type=bool false

Or for 12.04:

gsettings set org.gnome.desktop.screensaver idle-activation-enabled false

If you are running XBMC in its own session (you log in to xbmc from lightdm) you might be experiencing the same problem as me: How do I disable the screen saver in 12.04 system wide?


If you want a pure console version (something you could play over SSH, for example), try pacman4console (sudo apt-get install pacman4console). It's pretty ugly but it works.

But I don't think it's the best. I personally prefer pacman (sudo apt-get install pacman), mostly because it looks like the original Pacman game... But it's graphical. I don't understand why that's neccessarily a bad thing so I'm including it.

There are a couple of other graphical clones in the (njam which has multiplayer, and hannah) and there are several as part of compilations (gtkboard and childsplay both have Pacman clones).


Ubuntu 14.04: Add links to places in menu

Sorry for bringing up an old question, but the accepted answer explains how to add items to Bookmarks, not Places.  Sadly, you can't add to the Places list.

The items in Places are defined in .config/user-dirs.dirs.  Mine looks like this:

# This file is written by xdg-user-dirs-update
# If you want to change or add directories, just edit the line you're
# interested in. All local changes will be retained on the next run
# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
# absolute path. No other format is supported.
#
XDG_DESKTOP_DIR="$HOME/Desktop"
XDG_DOWNLOAD_DIR="$HOME/Downloads"
XDG_TEMPLATES_DIR="$HOME/Templates"
XDG_PUBLICSHARE_DIR="$HOME/Public"
XDG_DOCUMENTS_DIR="$HOME/Documents"
XDG_MUSIC_DIR="$HOME/Music"
XDG_PICTURES_DIR="$HOME/Pictures"
XDG_VIDEOS_DIR="$HOME/Videos"

You can freely add more directories but they are not listed in Nautilus.  You can change the folders to point to different directories or you can set them to "$HOME/" to remove them (see man xdg-user-dirs-update) but you are not able to add to them.  That's because the xdg tools (eg xdg-user-dir) have a fixed list of "Places" directories that can be set.  You can see this list with man xdg-user-dir:

This command expects the name of an XDG user dir as argument. The
possible names are:
    DESKTOP
    DOWNLOAD
    TEMPLATES
    PUBLICSHARE
    DOCUMENTS
    MUSIC
    PICTURES
    VIDEOS

Sorry, but you are not able to add new entries to the Places menu and have it recognized by the xdg-* tools.  Bookmarks are changeable.  Depending on the version and flavor of Linux you can find a menu item to add/edit bookmarks, press Ctrl-D, or press on a gear symbol to add a location as a bookmark.  Your bookmarks are stored in .config/gtk-3.0/bookmarks.  It appears that duplicate entries (ones in both Bookmarks and Places) only show up in Places, at least in Nautilus.


What to do when you install a new Wifi card?

If you are physically removing the old card and installing a different card in the machine, it shouldn't be necessary to do anything about the drivers. Drivers for most Intel cards and the required firmware are installed by default in recent Ubuntu versions.


kdelicious: delicious for konqueror

At last I managed to find a plugin for delicious in konqueror. The project is Called kdelicious (although There Are Several Projects That Are The Same Nearly extinct or name). The point is That There is no package to install so Then I Have Explained how to
compile and configure it.

Downloading and Compiling the sources

We have installed the packages: kdelibs5-dev make cmake git-core

git clone
git://github.com/greghaynes/kdelicious.git
cd kdelicious/
cmake -DCMAKE_INSTALL_PREFIX=/usr make

Installation

We have two options:

Using the Makefile target:

make [ install | uninstall ]

Create a debian package:

sudo checkinstall -D make install

dpkg [ -i | -r ] kdelicious_XXXXXXXX.deb

Configuring Konqueror

Activate the plugin:

settings > configure extensions

Activate the toolbar "extra" to see the icon

settings > toolbar  > extra toolbar

Show only the icon (no text)

right click on the icon > text possition > icons only

If we do not like the default icon that brings you can download the logo of delicious:

wget http://2.bp.blogspot.com/_ABRRWS9Ucgw/SlZlZ5I614I/AAAAAAAAAKQ/_jFllqGkpXM/ s400/delicious_logo.png
sudo mkdir -p /usr/local/share/icons
sudo mv delicious_logo.png /usr/local/share/icons

and to change the icon:

settings > configure toolbars
    Extra Toolbar
    change icon > other icons > browse

Done. We Can Comfortably saved links on delicious from konqueror INSTEAD OF HAVING to use the http:/delicious.com/save.


No sound on Virtualbox Ubuntu with Mac OS X host

I dont think this is an Ubuntu problem.
Since virtual box 5.0.26+ there has been problems regarding sound on an OSX host no matter the guest os.
More info:  https://www.virtualbox.org/ticket/15611

U could downgrade to .26 (be sure to fix the right version of the extention-pack too) or hope for an update where its fixed; even the latest test-builds don't work yet.

Edit: newest version VirtualBox 5.1.4 seems to work.


When you are in Texmaker, go to Options → Configure Texmaker and change the paths for the programs.


how to export an ssl certificate from one to another server? Server migration

SSL certificates are static files, so to copy a certificate to a new server all you need to do is simply copy the files between machines. The only caveat is to make sure that you copy all of the files.

There are usually three:

The certificate itself
The private key used to create the above certificate
The chain file, which traces which entities have signed the certificate (can be optional)

For switching from apache to nginx, you will need to read the nginx documentation on enabling SSL support.


Lubuntu 14.10 High CPU usage and choppy video playing

Sadly you are having an awful PC, the cpu worse than the only 1 GB of RAM.
What you installed?

Two must-have for a slow and outdated computer: preload and zram.

So, open terminal and type sudo apt-get install preload zram-config -y
Then reboot and tell me if your computer is in "better shape" ;)


Hard drive is detected but cannot mount when try to install ubuntu

You've probably got one or more bad blocks on the HDD, or the HDD is failing.

First, bring up the Disks app, go to SMART Data & Tests, and run the tests. Post the results as an edit to your question. Then look at the SMART Data window, and post screenshot(s). It may take two screenshots to capture all of the data for me to review.

After I review the SMART information, you may need to bad block the HDD, but wait until I give the go-ahead.

Second, to bad block the disk, and if the HDD is empty, or you have the data backed up elsewhere, use gparted to install a fresh MBR or GPT partition table (this will wipe the drive), and then create one large ext4 partition, and then follow these instructions to bad block the disk...

    Note: do NOT abort a bad block scan!

    Note: do NOT bad block a SSD

    Note: backup your important files FIRST!

    Note: this will take many hours

    Note: you may have a pending HDD failure

Boot to a Ubuntu Live DVD/USB.

In terminal...

sudo fdisk -l # identify all "Linux Filesystem" partitions

sudo e2fsck -fcky /dev/sdXX # read-only test

or

sudo e2fsck -fccky /dev/sdXX # non-destructive read/write test (recommended)

The -k is important, because it saves the previous bad block table, and adds any new bad blocks to that table. Without -k, you loose all of the prior bad block information.

The -fccky parameter...

   -f    Force checking even if the file system seems clean.

   -c    This option causes e2fsck to use badblocks(8) program  to  do  a
         read-only  scan  of  the device in order to find any bad blocks.
         If any bad blocks are found, they are added  to  the  bad  block
         inode  to  prevent them from being allocated to a file or direc‐
         tory.  If this option is specified twice,  then  the  bad  block
         scan will be done using a non-destructive read-write test.

   -k    When combined with the -c option, any existing bad blocks in the
         bad blocks list are preserved, and any new bad blocks  found  by
         running  badblocks(8)  will  be added to the existing bad blocks
         list.

   -y    Assume  an answer of `yes' to all questions; allows e2fsck to be
         used non-interactively.  This option may not be specified at the
         same time as the -n or -p options.


How do I create a boot disk from an existing installation?

I use Relinux quite often to build a live/installable iso from a preconfigured system, including settings and files in my home folder.  Relinux Download page

A little guide to get you going Relinux guide
To keep your settings you will need to run this from terminal cd && sudo cp -r . /etc/skel/ before you make the iso.  Any problems, just ask.


What do you mean? Resolution, monitor's name?

You should try adding xrandr command output here.

Also, are you using any DVI->VGA connector? I've had problem same problem with one. My solution was changing it to good one (Gigabyte) and it worked just fine!


How can I have two launchers, one on the left side of my left screen and on the right side of my right screen?

There is no supported mechanism for doing this; the launcher is designed to be on the left-hand side of the screen.

Hacks like those seen on this question might be developed (Unity is open source, after all), but I don't expect such a feature to be merged into mainline Unity.


How to recieve streamed audio with Chromium in Lubuntu?

It's a bug reported here with firefox plugin gecko-mediaplayer ported to chromium. The issue is still open and the developers seem a bit clueless.

A workaround would be to install another plugin, for example vlc which is also a very simple but good media player and has a browser plugin.

$ sudo apt-get install vlc browser-plugin-vlc

Ubuntu package description: http://packages.ubuntu.com/raring/browser-plugin-vlc
VLC official homepage: http://www.videolan.org/vlc/

Give it a try until gecko-mediaplayer is fixed.


For your first question, you should be able to do this by running some Javascript inside the WebView with WebView.experimental.evaluateJavaScript().  This Javascript could get the page source (or better yet, just the content you want, since it'll be better at parsing HTML than the Javascript-in-QML) and report it back via the document title.  For example,

webview.experimental.evaluateJavaScript(
    "document.title = document.getElementById('id').innerHTML")

I'll admit that I don't know much about OAuth, but I can't help but feel you're doing something wrong if you need to do this.  Have you checked out Online Accounts or this OAuth plugin?


How can I get Policykit-1-KDE to preselect the current user?

For what I have seen this would need to coding in the source for it. I recommend filing a report about this so they can added in a new release. The workaround you mention would work since there would be only one but like you just said, an preselected option should be available when multiple users exist, at least to save up on time from selecting the user (or previous user if it was selected earlier).


Output the current PATH to text file using BASH script

You change your PATH with command:

PATH=/new-path:$PATH

For example here is how to correctly expand the PATH:

$ PATH=/newpath:$PATH
$ echo $PATH
/newpath:/home/rick/bin:/home/rick/.local/bin:/mnt/e/bin:/mnt/e/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin

Here is just one way to break your PATH (by omitting $ prefix):

$ PATH=/brokenpath:PATH
$ echo $PATH
/brokenpath:PATH

If you mess up your PATH usually you can simply close your terminal and reopen it.

Omitting the $ is the mistake made in your question as well. The method to capture PATH to text file is:

echo $PATH > PATH.TXT

To keep a running log of PATH changes you can use:

echo $PATH >> PATH.TXT

PATH is an environmental variable. To set the variable we use "PATH=" but to reference it's contents we need to use "$PATH".

The PATH variable can be set in many places as outlined in this Q&A: Where is my PATH variable being set?. To discover which files are setting the PATH one of the answers recommends using:

grep --color -H 'PATH=' ~/.bashrc ~/.profile ~/.bash_profile ~/bash.login \
                     ~/.bash_aliases /etc/bash.bashrc /etc/profile \
                     /etc/profile.d/* /etc/environment 2> /dev/null

On my machine the command returns:

/home/rick/.profile:PATH="$HOME/bin:$HOME/.local/bin:$PATH"
/etc/profile.d/apps-bin-path.sh:    export PATH=$PATH:${snap_bin_path}
/etc/profile.d/jdk.sh:export PATH=$PATH:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
/etc/environment:PATH="/mnt/e/bin:/mnt/e/usr/local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"


Can I use iptables to forward vm guest requests to host

iptables is likely not the tool to do what you wish.  However, you may want to use iptables to block access from the internet.

Network traffic on the lo device should not be routed to another device, even a virtual device.  It is likely that virtualbox has created a br0 devices or some device with br in the name.  The IP address of this device would be your best choice to connect to mysql on.

The virtual server should be able to connect directly to the mysql server, if it is listening on a reachable address.  It is common for mysql to be configured to listen on the loopback (127.0.0.1) address as a security measure.  Use the command sudo netstat -antp | grep mysql to determine which IP addresses mysql is listening on.  If it is only listening on 127.0.0.1 or ::1, you will need to adjust the mysql configuration. If it is listening on 0.0.0.0, mysql will be reachable on any public address of your server.


Access music on Windows partition while dual-booting Win10/Ubuntu?

Ubuntu Linux can’t access Win10 system drive because Windows does not fully shut down (it actually hibernates). So you have to choose:

Do a full shutdown – When you’re in Windows select “Restart” option or hold the SHIFT key when clicking “Shutdown” option.
or Disable Fast Startup – Launch Control Panel and do:
    navigate to Power Options -> Choose what the power buttons do
    click the link “Change settings that are currently unavailable” at the top
    uncheck the “Turn on fast startup” box under Shutdown settings.

1. Fully shutdown Windows 10, or disable Fast Startup
More info here http://ubuntuhandbook.org/index.php/2016/01/mount-windows-10-in-ubuntu/
Hope this helps.


Be sure to add the -enable-kvm option to allow QEMU to use hardware virtualization capabilities (requires Intel VT-x or AMD AMD-V CPU extensions). Without those options, everything will be emulated in software (which is much slower). Example:

qemu-system-x86_64 -enable-kvm -m 1024 -name mac -hda ~/Documents/ubuntu1


Extend gnome-control-center’s list of keyboard layouts

The list can be found in /usr/share/X11/xkb/rules/evdev.xml, and it can be extended.

The translations can be found in xkeyboard-config.mo for the respective language.


How to change ownership and permissions of automatically mounted HDD

You don't change change ownership and permissions of an automatically mounted HDD. Microsoft file systems (NTFS, FAT32, exFAT) get their ownership and permissions when mounted, and directories and files inherit them.

Instead you

control the mounting with a line for the partition(s) in the file /etc/fstab
if already mounted, you unmount and remount the partition(s) using umount and mount with mount options to get the ownership and permissions, that you want.

The same mount options can be used in /etc/fstab and with mount.

This is described in a detailed way in the following links,

How do I use 'chmod' on an NTFS (or FAT32) partition?

Mount USB with exec flag by default


From the comments, the output of sudo apt-get install -f command shows,

Reading package lists...
Done Building dependency tree Reading state information...
Done The following package was automatically installed and is no longer required:
jockey-common
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 438 not upgraded

The above error report shows clearly that you have to run sudo apt-get autoremove command to automatically remove all the unused packages.In your case it's jockey-common. While running sudo apt-get autoremove command, it removes automatically jockey-common package.And also sudo apt-get install -f will solve dependency problems.


Error install nvidia-387: Error! Bad return status for module build on kernel:

Looks like the issue is cause by some shuffling of linux headers in some recent linux kernel updates.

Relevant discussion:
https://devtalk.nvidia.com/default/topic/1028016/linux/patch-for-compiling-v384-98-modules-with-linux-v4-14-9-/

I had the exact same issue and I fixed it by applying the patch suggested by user PGNd  in the discussion above.

Step by step instructions for manual edit of the nvidia src files on Ubuntu 16.04:

sudo apt-get install nvidia-387 (this will fail)
sudo nano /usr/src/nvidia-387-387.26/nvidia-uvm/uvm8_va_block.c
(you should replace nvidia-387-387.26 with the version you are trying to install.)
Add the line #include <linux/sched/task_stack.h> before the other include statements at the beginning of the file
Run sudo dpkg-reconfigure nvidia-387 to rebuild the nvidia driver
Reboot

This should work as a temporary workaround until nvidia releases a fix.
I was able to install cuda-9.1 after doing this.


Connect Dell XPS13 9360 via Thunderbolt3/USB-C to a DP monitor

My Dell based laptop powers two external displays, one via HDMI the other via Thunderbolt 3 Displayport with an external USB-C to HDMI converter.

Contrary to other advise it works perfectly in Ubuntu 16.04 with Intel HD530 graphics (Sky Lake i7 6700HQ). nVidia drives the HDMI port:


IPtables Config to Passthrough Internet 16.04

After a bit of searching I figured out that I wanted to use a Bridge instead of IPTables. Otherwise, the connection would require another NAT/DHCP. The configuration of the Bridge is trivial, more detail can be found: https://help.ubuntu.com/community/NetworkConnectionBridge


Swap CTRL and caps lock in tty1 (deeper than gnome)

Open /etc/default/keyboard for editing and change the line

XKBOPTIONS=""

to

XKBOPTIONS="ctrl:swapcaps"


Ok found the solution, I had to update my system, so i went to software sources and then I Checked all checkboxes in the 3 first tabs Ubuntu software,Other software,Updates
after everything was checked I ran the following command:

sudo apt-get dist-upgrade

Then to install bind9

sudo apt-get install bind9


Audio recording on Ubuntu Phone Aquaris E4.5

Have you tried the solutions provided in this forum topic:
http://ubuntuforums.org/showthread.php?t=2276546

According to the comments in the Ubuntu App Store soundtrap doesn't work on the Aquarius, so you're left only with the terminal solution for now.

//EDIT:

I also found this thing but it seems it's only source code and you'll have to compile it yourself - http://stefano92100.blogspot.com/p/audiotape.html

//EDIT 2:

There seems to be a new app designated for this purpose. It si called 'recorder' and it can be downloaded from the app store.
https://uappexplorer.com/app/recorder.pramathesh


Grub is not presenting kernel 3.2 as an option

You should have grub-pc package installed. With that, run:

cd /boot/
sudo update-grub


The issue here is that the directive ServerName is missing within the <VirtualHost> tags. This is necessary to identify the virtual host.

Also, for this case, it is a good idea to use the directive Redirect with the option permanent - read the section "Redirect Methods" in this article.

ServerName example.com # This directive provides a global server name.
                       # But you should set ServerName also for each virtual host
                       # to identify it!!!

<VirtualHost *:80>
    ServerName example.com
    # Redirect Requests to HTTPS with HTTP 301 status
    Redirect permanent "/" "https://example.com/"

    # Other configuration directives...
</VirtualHost>

<VirtualHost _default_:443>
    ServerName example.com

    # Other configuration directives...
</VirtualHost>

Apply the configuration change and restart (or reload) Apache. Then flush your browser's cache or use an incognito window (or another browser) to see the change.

For this task you can use also rewrite rules as it is illustrated in this question, but within the Apaches documentation you will be advised to do not use the rewrite engine when you can use more simple directives.


You'll have to press the f-key. Unison is waiting for you to confirm to proceed with the synchronization. The arrow means that it will sync from local to MacBook.l.


Intel wireless not working after apt update and upgrade

I had this issue today when somebody installed Ubuntu 20.10 instead of 20.04 after internet searches and trying lots of things I resolved the problem.
I downloaded the 20.04 latest Linux firmware linux-firmware_1.187.4_all.deb
then I uninstalled the 20.10 version using
dpkg -r --force-depends linux-firmware

then installed the old package
dpkg -i linux-firmware_1.187.4_all.deb

Rebooted and everything worked fine...


laptop shuts down due to overheating during ubuntu installation

Try blowing the vents clear with canned air and perhaps working in a cooler environment. This should help with the overheating problem which is extremely likely to be the root cause of your difficulties.


t2.micro Ubuntu 16.04 ran out of space - Debug help

This is because of the instance running out of inodes. Check this post on running out of inodes for debugging the regular way.

I solved this by adding additional storage to my volume and doing appropriate configuration. Please note that additional storage may cost you.


Rename files to be capitalised but not impact on file extensions

One way to achieve this might be to use Negative Lookbehind to only match the word-boundary - word character sequence when it is not preceded by a literal period e.g. given

$ ls
alan's file.txt  bar.txt  foo

then

$ rename -n 's/(?<!\.)\b\w*/\u$&/g' *
rename(alan's file.txt, Alan'S File.txt)
rename(bar.txt, Bar.txt)
rename(foo, Foo)

Assuming you also want to avoid capitalizing the pluralizing s as well, we might modify that to

$ rename -n 's/(?<![.'\''])\b\w*/\u$&/g' *
rename(alan's file.txt, Alan's File.txt)
rename(bar.txt, Bar.txt)
rename(foo, Foo)

or even

$ rename -n 's/(?<![[:punct:]])\b\w*/\u$&/g' *
rename(alan's file.txt, Alan's File.txt)
rename(bar.txt, Bar.txt)
rename(foo, Foo)


Update June 16, 2019
Last month, 2 years after problem was reported, OP discovered LightDM (Ubuntu Unity Desktop Manager) was source of problem. That said, in addition to the list below, there is another grub parameter that can be tried:
video.use_native_backlight=1

See this answer for more.

Original Answer
The ultimate reference seems to be in Arch Linux which is a site I've turned to many times to fix difficult problems.
Kernel Parameters
Looking at your cat /proc/cmdline there are no extra kernel parameters passed. The above link states:
Sometimes, ACPI does not work well due to different motherboard implementations and ACPI quirks. This includes some laptops with dual graphics (e.g. Nvidia/Radeon dedicated GPU with Intel/AMD integrated GPU). On Nvidia Optimus laptops, the kernel parameter nomodeset can interfere with the ability to adjust the backlight. Additionally, ACPI sometimes needs to register its own acpi_video0 backlight even if one already exists (such as intel_backlight), which can be done by adding one of the following kernel parameters:
acpi_backlight=video
acpi_backlight=vendor
acpi_backlight=native

If you find that changing the acpi_video0 backlight does not actually change the brightness, you may need to use acpi_backlight=none.
Try each of the acpi_backlight=xxxx options on your grub kernel paremeters line
When xbacklight doesn't work
You've tried xbacklight already and the link above addresses this:
On some systems, the brighness hotkeys on your keyboard correctly modify the values of the acpi interface in /sys/class/backlight/acpi_video0/actual_brightness (As we tried in comments) but the brightness of the screen is not changed. Brigthness applets from desktop environments (ie Ubuntu brightness setting slider bar) may also show changes to no effect.
If you have tested the recommended kernel parameters and only xbacklight works, then you may be facing an incompatibility between your BIOS and kernel driver.
In this case the only solution is to wait for a fix either from the BIOS or GPU driver manufacturer.
A workaround is to use the inotify kernel api to trigger xbacklight each time the value of  /sys/class/backlight/acpi_video0/actual_brightness changes.
First install inotify-tools. Then create a script around inotify that will be launched upon each boot or through autostart.
Below is script you need to create called: /usr/local/bin/xbacklightmon
#!/bin/sh

path=/sys/class/backlight/acpi_video0

luminance() {
    read -r level < "$path"/actual_brightness
    factor=$((100 / max))
    printf '%d\n' "$((level * factor))"
}

read -r max < "$path"/max_brightness

xbacklight -set "$(luminance)"

inotifywait -me modify --format '' "$path"/actual_brightness | while read; do
    xbacklight -set "$(luminance)"
done

There is a lot more in the link above but these steps are a good place to start.

Dedicated Forums
For additional support there are dedicated Linux Graphics forums:

Phoronix Linux/AMD/Nvidia support with many Ubuntu users
Nvidia Linux Developers Forum (with many Ubuntu specific topics)


Settings LDAP Users Roles/Permissions at Application Level

This question is quite old but I'll give in my experience.

Use LDAP for authentication, not for authorization.  This means that the PHP app should authenticate a user against the LDAP server and grant authorization based on internal policies (validated against groups the user may be in, for instance).  Most web frameworks out there should provide a wide variety of LDAP authentication libraries.  This way, authorization is decentralized and simplified in medium/long term.

In case of application directly run on a client machine, note that LDAP will preserve posix groups and the following question could help: How can I restrict program access to other users?


Permission denied error during "hadoop namenode -format" command

If it says permission denied, you probably need sudo.

Try this command instead:

sudo hadoop namenode -format

It may not be needed, but as you are having issues it may help. The tutorial suggests it will be modifying folders in /usr - this could be the issue.


I was able to fix the problem by disabling this flag chrome://flags/#ntp-webui (Use the WebUI new tab page when opening a new tab). Checked on  chromium version 88.0.4324.96.
It is possible that in the next releases the WebUI functionality will be restored.


Mounting errors in fstab while NAS is off

Try changing this in /etc/fstab:
ip_nas:/folder  /mnt/folder nfs defaults    0   0

To this (this assumes that ip_nas is in your /etc/hosts file, else use IP address):
//ip_nas/folder  /mnt/folder nfs defaults,nofail,x-systemd.device-timeout=30    0   0

or
//192.168.x.x/folder  /mnt/folder nfs defaults,nofail,x-systemd.device-timeout=30    0   0

And see if that helps. Report back.


Read string with $USER variable as text and resolve it

read does not expand variables from your config file.

You can verify that:

$ read username
$USER
$ echo $username
$USER

This answer on Stackoverflow gives a solution.
Change your script to this to make it expand variables:

while read var value
do
    export "$var"="$value"
done < <(envsubst < my-conf-file.conf)


Fixed by changing connection type to "Automatic (DHCP) addresses only" and specifying dns servers inside the connection. I suppose issue was with DNS or the router.


I need to import pictures twice in Shotwell

I had the same problem.

Shotwell used to compare md5; see How does Shotwell detect duplicates?.

I could not find how to set variable NO_DUPE_DETECTION. The only solution for me was to change the md5 PhotoTable field of the table using

sqlite3 ~/.local/share/shotwell/data/photo.db  "update phototable set md5=''"

You can add a function to .bashrc

rmmd5 ()
{
sqlite3 ~/.local/share/shotwell/data/photo.db  "update phototable set md5=''"
}

and run it every time you import.


As suggested by Saiarcot895,
best way to know if your PC is compatible with Ubuntu : it is to test Ubuntu on your PC, directly yourself with a Live Disk OR a Live USB:

see How to burn a DVD on Ubuntu from Windows or from Mac or from Ubuntu
see How to create a bootable USB stick on Ubuntu from Windows or from Mac or from Ubuntu

Then follow these instructions for installing Ubuntu (you will get the choice to Install or Test)


Execute command on reattaching byobu | screen | tmux session

I found a way to execute commands, not on reattaching but on idle:
first I changed the byobu backend to screen, then I created a .screenrc in ~/.byobu containing

blankerprg  zsh -c "while true; do run-parts --lsbsysinit /etc/update-motd.d; sleep 30; clear; done"
idle        600 blanker

That uses screen's screensaver functionality to display text I would normally only see on login.


Ok well, I found it. But it's messy...

My error was caused by util-linux(in buggy version 2.20 since 2012), which is needed by udisks, which is the package used by gnome-disks to format USB drives, which is the tool used by the "Format" option in the Nautilus context-menu.

The bug is reported here and here. It has not be solved since 2012.

Thats a bummer...

EDIT : and if you want my advice, DO NOT try to build util-linux yourself^^ I just did, following all recommendations and without any warnings, and I bricked my system.


You have to use a command to connect to your URL like curl. Just entering the URL in bash does not work.

curl http://6.5.4.2

That should print the HTML in your terminal. If you want to interpret the HTML code you could use lynx which is a text-based web browser for shell.

lynx http://6.5.4.2


How to Stop Screen Blinking Because of High Memory Usage?

Go in Chromium settings Disable hardware acceleration.
In the URL bar type chrome://flags/ enable Override software rendering list.


apt-get upgrade freezes at "Waiting for Headers"

Issue Solved,
There was problem with some repository links in sources.list file.I was unable to get updates from google so it was freezing at starting point. After removing the entry for google updates it works fine !!!


How to see results after updating .gtkrc?

I've used an app before that is like firebug for GTK, called Parasite but it can't update the widgets in the sense you are suggesting.

You could try something like:

sudo compiz --replace &

if you're using compiz, that is.

Another thing you could try would be to put the commands to change the theme in a script, and assign it to a keyboard shortcut. That way you could change your .gtkrc, hit the keyboard shortcut and watch as you save a minute of your life.

I did a quick google search and found this thread on ubuntu forums.
The script would look something like this (assuming the theme you want to end up with is Ambiance, and the icon theme is ubuntu-mono-dark):

#!/bin/bash

#Change GTK theme:
gconftool-2 --type=string -s /desktop/gnome/interface/gtk_theme Clearlooks
gconftool-2 --type=string -s /desktop/gnome/interface/gtk_theme Ambiance

#Change Metacity theme:
gconftool-2 --type=string -s /apps/metacity/general/theme Clearlooks
gconftool-2 --type=string -s /apps/metacity/general/theme Ambiance

#Change Icons:
gconftool-2 --type=string -s /desktop/gnome/interface/icon_theme gnome
gconftool-2 --type=string -s /desktop/gnome/interface/icon_theme ubuntu-mono-dark

You may still need to close and re-open applications for the changes to take affect.


How can I reduce the file size of a video from the command-line?

This should start with a caveat, that transcoding between lossy media formats will generally involve loss of quality.

There are lots of options here:

Convert older formats (MPEG-1, DivX 3 etc) to newer and more efficient codecs (eg x264, theora) which will generally mostly preserve video/audio quality in a smaller output.
Reduce the target bitrate or target output size, improving size at the cost of reproduction quality.
Reduce the video dimensions, allowing similar reproduction quality at lower total size.

Unless you have strong reasons for another choice, x264 for video and aac for audio in an mp4 container is a good choice for quality and reasonably wide compatibility (but you should encode something short and try it on anything you'll want to play it on - getting widely playable transcoded results remains an exercise in witchcraft).

I find the current command serves me fairly well for converting older formats:

avconv -y -i INPUT -pre:v libx264-slower -b:a 96k -c:v libx264 -c:a libvo_aacenc OUTPUT.mp4

You can scale down the image size by adding -vf scale=iw*0.5:ih*0.5 before the output name, or set a video bitrate -b:v, or play with multi-pass options... but mostly the above will produce a reasonable outcome.


dpkg error: "trying to overwrite file, which is also in..."

To fix your problem run

sudo dpkg -i --force-overwrite /var/cache/apt/archives/libjline-java_1.0-1_all.deb

check everything is fixed by running : sudo apt-get -f install

If you still have problems rerun the first step with any dpkg: error processing (...) remaining

Solution found on webupd8


Intel/AMD Hybrid graphics on Ubuntu 14.04

With the release of Ubuntu 14.10, some of the problems related to this incompatibility issue appear to be solved. I succeeded to make both graphic cards to work as follows:

1) Install Ubuntu 14.10. In my case, I first tried updating from 14.04 but I messed up with the installation. I ended up doing a clean install from an Ubuntu CD.

2) Install the fglrx driver from "Software & Updates" -> "Additional Drivers".

3) Reboot

4) Unfortunately, the AMD  Catalyst Control Center behave weirdly. The first time I run it, it did run normally. I used it to switch the card. After a reboot, the AMD Catalyst Control Center did not run anymore. To switch between cards, please follow the step 5).

5) Check whether you are using the discrete card (radeon) or the integrated one (intel) by running the in a terminal:

amdconfig --pxl

If you are using the Intel card, you should see a message like:

PowerXpress: Integrated GPU is active (Power-Saving mode).

Otherwise you will see a similar message stating that the discrete card is currently in use. To switch from using the discrete card to the integrated one, run the following command:

amdconfig --px-igpu

For the other way around, run the following command:

amdconfig --px-dgpu

In both cases you will be prompted to restart the X server. You may log out and log in again for the changes to take effect.


Ubuntu 13.04 random lockup - Xorg dying, colored squares

Reinstalling the Nvidia drivers might solve your problem:

sudo apt-get purge nvidia*
sudo apt-get install nvidia-current
sudo reboot


What's the absolute path of an icon declared in a .desktop file?

It's dependent on the icon theme. If the icon is not given by an absolute path, following rules are used to find the icon:

The lookup is done first in the current theme, and then recursively in each of the current theme's parents, and finally in the default theme called "hicolor" (implementations may add more default themes before "hicolor", but "hicolor" must be last). As soon as there is an icon of any size that matches in a theme, the search is stopped.
[...]
The lookup inside a theme is done in three phases. First all the directories are scanned for an exact match, e.g. one where the allowed size of the icon files match what was looked up. Then all the directories are scanned for any icon that matches the name. If that fails we finally fall back on unthemed icons. If we fail to find any icon at all it is up to the application to pick a good fallback, as the correct choice depends on the context.

See the Icon Theme Specification for details.


My answer here mentions the why, but for the specific reasons to not enable it by default, comes down to several important factors that affect different hardware, hardware configurations and software configurations but they basically boil down to:

What file system to use? (Not all filesystems support TRIM. In fact, only a small group of filesystems support TRIM including ext4 and btrfs)
What SSD to use? (Some are not good with TRIM. Some don't need TRIM)
Will RAID be used? (There are several RAID issues when using TRIM)
What performance impact will it have? (Negative, Positive. This varies depending on SSD, hardware, RAID configuration...)

So I guess with all of this doubts, the option for one to test it out ourselves is left with the manual approach and to see if there is an actual benefit. I can say that the benefit in an Intel 520 with and without Trim is very little, at least in my case. But still, with all of this performance issues, enabling automatic TRIM even will all of the hype about it would still be a bad idea because for some users it will be good, but for others it could be very bad.


My headset has a jack for both speaker and microphone. My laptop has a single headset jack input. How can I record sound from my headset?

It's not a software issue, it's a hardware incompatibility issue. You see, your headset has a 3-contact plug, and your computer has a 4-contact socket. This can only be fixed by:

Buying an adapter from 3-contact (earphones) + 2-contact (microphone) plug to 4-contact (earphones + microphone) plug.

or

Buying a headset that has a 4-contact plug.


If it's the default ecryptfs filesystem there is no way to crack it without the key/password. Maybe if you were NSA, but probably not. :-/


Shift+F2 is ignored when using byobu with PuTTY (Windows 7)

I'm using Putty 0.73 on windows 10 (1903) connecting to Ubuntu 18.04 and byobu 5.125 and tmux 2.6.

I set Putty->Terminal->Keyboard->"Function keys and keypad" to Xterm R6.  This solves some problems but not the Shift-F2 issue.

Can't find any further method of changing Putty key bindings.

I'll investigate changing byobu key bindings.  Any other help on using Putty with Ubuntu and byobu?


Can't upgrade OS Install (MATE); How to solve, please?

The simplest solution is to remove vivaldi.list with:
sudo rm /etc/apt/sources.list.d/vivaldi.list

and then run
sudo apt-get update
sudo apt-get upgrade


I know this post is a few months old. I'm sure somebody will find it of use.

Go to: http://ubuntuforums.org/showthread.php?t=2262459&page=5

As long as you have at least Ubuntu kernel 3.19 then proceed to step 2 of post #44. I did it and it worked like a champ.

There is a bug (that I have noticed hasn't manifested itself lately... maybe it's fixed by now?) where Ubuntu will sometimes freeze when you hover your mouse over the wifi icon near your clock.


Use MonoDevelop but beware of the quirks of X-platform .NET development

First, install mono by either finding it in the Software Centre or typing

sudo apt-get install monodevelop mono-vbnc

MonoDevelop is pretty equivalent to Visual Studio Express the major differences being:

MonoDevelop doesn't support WPF (Windows Presentation Foundation) but that shouldn't matter much as Microsoft has plans to kill WPF with the arrival of Windows 8.
Verify that the correct .NET framework target is being used. After creating a solution, right click on the project and goto Options->Build->General. Not much different from targeting a specific version of .NET on Windows.

Aside from those issues, I haven't really found anything missing that I can't live without.

The only other issue (non mono related) that may come back to bite you is the classic line ending problem. *nix still uses LF and Windows still uses CRLF for line endings so, when you transfer your source files back and fourth between Windows/*nix. AFIAK, MonoDevelop saves source files in UTF-8 by default but VS saves source files in Windows ASCII (with windows-1252 latin ASCII with windows specific line endings). If you receive source files that were created using Visual Studio you may need to convert the format to get it to work in *nix.

As you can see, x-platform .NET development can be a little challenging at first but IMHO, it's worth it. I like MonoDevelop's non-cluttered interface (the visual effects in VS just get in the way most of the time), it loads in a fraction of the time that VS does (useful if you don't typically leave your IDE open all the time), it takes up a fraction of the space with no extra unnecessary addons (VS is really obnoxious about this).

Installing it was easy as sudo apt-get install monodevelop. Also, popular tools like NUnit (for unit testing) have been ported over to and work flawlessly in *nix. The Windows version of MonoDevelop kinda sucks (or at least it did last time I tried it).

Update:

To get VB code to compile you'll also need to install the VB compiler module:

sudo apt-get install mono-vbnc

I also updated this answer to remove some of the problems that are no longer relevant.


How do I find out which version and derivative of Ubuntu is right for my hardware in terms of minimal system requirements?

Preliminary notes

First of all it makes no sense to install versions of Ubuntu that are no longer supported with updates. The reasoning is discussed at the bottom of this answer.
This answer will concentrate on currently supported versions of Ubuntu and its official derivatives.
If your hardware never connects to the internet and if you will never use software newer than is included on the respective install media, only then might it be prudent to use outdated versions. But who can be sure of that for all eternity?
You don't have to install Ubuntu to see if it works on your hardware. It is always a good idea to boot from live DVD/USB and see if the system runs okay (although slowly) on the given hardware.
Even if it seems not to work, you might be just one boot option away from a working system. See My computer boots to a black screen, what options do I have to fix it? For example the nomodeset option might help.

Currently supported versions and their minimal requirements
The community wiki usually offers an up-to-date list of currently supported versions. Minimal system requirements for Ubuntu can be found there in the tech specs. The Lists of Ubuntu certified hardware might also be of use to you.
Information on the derivatives is scarce but their requirements are less than what is listed here. Generally 32-bit versions take up less memory and tend to be faster on older systems, than their 64-bit counterparts. However, allot of software nowadays assumes 64-bit architecture. If you are unsure, install the 64-bit versions.
Supported versions of Ubuntu

20.04 and later Desktop recommended system requirements

2GHz dual core processor or better

4GB RAM

25GB of disk space

VGA capable of 1024x768 screen resolution

Either a DVD drive or a USB port for the installation media

Internet access is helpful

16.04 Desktop recommended system requirements

2GHz dual core processor or better

2GB RAM

25GB of disk space

Graphics processor and display capable of at least 1024x768

Either a DVD drive or a USB port for the installation media

Internet access is helpful

16.04 Desktop minimal

In order to run Unity the system needs a more capable graphics adapter.

Intel Pentium 4 processor or better

1GB RAM

Graphics processor and display capable of at least 1024x768

10 GB of disk space

17.10 and later Desktop recommended system requirements

64-bit 2GHz dual core processor or better

4GB RAM

25GB of disk space

Graphics processor and display capable of at least 1024x768

Either a DVD drive or a USB port for the installation media

Internet access is helpful

17.10 and later Desktop minimal

64-bit processor for iso, Intel Pentium 4 processor or better for installation using the Ubuntu minimal CD. The Ubuntu minimal CD (for Ubuntu 18.04 and earlier) supports installation of Ubuntu on computers that have a 32-bit processor.

1GB RAM

Graphics processor and display capable of at least 1024x768

10 GB of disk space

Updates will be provided for Ubuntu 18.04 for 5 years until April, 2023. Updates will be provided for Ubuntu 19.10 for 3 months until July, 2020.

16.04 and 18.04 Server installation standard

Ubuntu Server supports 3 major architectures: Intel x86, AMD64 and ARM.
1 GHz processor
512 MB of system memory (RAM)
1 GB of disk space (base system)
1.75 GB of disk space (all tasks installed)
Graphics card and monitor capable of 640x480

16.04-21.04 Server installation minimal

Ubuntu Server supports 3 major architectures: Intel x86, AMD64 and ARM.
300 MHz processor
256 MB of system memory (RAM) 64-bit, 192 MB RAM 32-bit
700 MB of disk space (base system)
1.4 GB of disk space (all tasks installed)
Graphics card and monitor capable of 640x480

Security and maintenance updates will be provided for Ubuntu Server 16.04 until April, 2021 and for Ubuntu Server 20.04 until April, 2025.
Supported versions of Xubuntu
See Xubuntu help page.

16.04-18.10

Minimum systems requirements
To install or try Xubuntu within the Desktop/Live CD, you need 512MB
of memory, 700 MHz processor and 7.5GB of free space on your hard disk.
Recommended systems requirements
To get a smooth experience when running multiple applications in parallel on the desktop, it is recommended to have at least 1GB of memory. It is recommended to have at least 20GB of free disk space. This allows new application installations as well as saving your personal data on the hard disk in addition to the core system.

Security and maintenance updates will be provided for Xubuntu 16.04 for 3 years until April, 2019 and for Xubuntu 20.04 for 3 years until April, 2023. Security and maintenance updates will be provided for Xubuntu 19.10 for 9 months until July, 2020.

19.04 and later

Minimum systems requirements
To install or try Xubuntu within the Desktop/Live CD, you need 512MB
of memory, 64-bit 700 MHz processor and 7.5GB of free space on your hard disk.
Recommended systems requirements
To get a smooth experience when running multiple applications in parallel on the desktop, it is recommended to have at least 1GB of memory. It is recommended to have at least 20GB of free disk space. This allows new application installations as well as saving your personal data on the hard disk in addition to the core system.

Supported versions of Lubuntu

16.04-17.10

Processor (CPU)
The minimum specification for CPU is Pentium 4 or Pentium M or AMD K8. Older processors are too slow and AMD K7 has problems with flash video.
Memory (RAM)
For advanced internet services like Google+, YouTube, Google Docs and Facebook, your computer needs at least 1GB RAM. Install Lubuntu 32-bit for computers with <= 3GB RAM.
For local programs like LibreOffice and simple browsing habits, your computer needs at least 512MB RAM.

18.04 and 18.04

Processor (CPU)
The minimum specification for CPU is Pentium 4 or Pentium M or AMD K8. Older processors are too slow and AMD K7 has problems with flash video.
Memory (RAM)
For advanced internet services like Google+, YouTube, Google Docs and Facebook, your computer needs at least 2GB RAM. Install Lubuntu 32-bit for computers with <= 3GB RAM.
For local programs like LibreOffice and simple browsing habits, your computer needs at least 1GMB RAM.

19.04 and later

Processor (CPU)
64-bit processor
Memory (RAM)
For advanced internet services like Google+, YouTube, Google Docs and Facebook, your computer needs at least 2GB RAM.
For local programs like LibreOffice and simple browsing habits, your computer needs at least 1GMB RAM.

Lubuntu Alternate ISOs are for low-RAM PCs. Computers with less than 700 MB of RAM are considered low-RAM computers. Instructions are here.
Updates will be provided for Lubuntu 20.04 for 3 years until April, 2023. Updates will be provided for Lubuntu 19.10 for 9 months until April, 2020.
Supported versions of Ubuntu Core
Ubuntu Core, with an image size of 260MB, is the smallest Ubuntu release to date. This makes it ideal both for IoT devices and cloud containers. A new release of Ubuntu Core is released every 2 years on even numbered years (2016, 2018, 2020, etc.).

Processor – 600MHz processor (ARMv7 or greater, or x86)
System Memory – 128MB RAM or greater
Storage – 4GB flash / storage for factory reset and system rollback

Ubuntu Core 16, 18 and 20

Ubuntu Core 16 is based on Ubuntu 16.04, and is supported for 5 years.

Ubuntu Core 18 is based on Ubuntu 18.04, and is supported for 10 years.

Ubuntu Core 20 is based on Ubuntu 20.04, and is supported for 10 years.

RAM Usage of different flavors of 18.04 under baseline conditions  (Click image to enlarge)

Why you shouldn't use versions when their support has ended

Security risks: Eventually there will be an exploit that compromises security or system integrity of old Ubuntu versions
Software incompatibilities: Versions that are no longer supported will have increasing problems with this. Due to the lack of updates one will no longer be able to open the most recent LibreOffice documents or compile programs that need more recent libraries. Hardware drivers of recent devices will not be included in older kernels.
Decreasing availability of repositories: It might become very difficult to download software that does not already ship with the outdated version. Hosting repositories for very old versions cease to be economically viable at one point.


how can i change in this file "ip_local_port_range"?

For the change in a running system use

sudo sysctl -w net.ipv4.ip_local_port_range="1024 65000"

or

echo "1024 65000" > /proc/sys/net/ipv4/ip_local_port_range

To survive a reboot, open the configuration file

sudo nano /etc/sysctl.conf

and add the lines below

# increase system IP port limits
net.ipv4.ip_local_port_range = 1024 65000

After the next reboot you can see, the correct values are set.


Ubuntu 15.10 | ETPS/2 Elantech Touchpad | Lag & Delay

I am having the same problem, and still have no solution. However, I think a way to solve it is bu modifying the xinput settings.

Reasoning:
- In my Lenovo, the trackpad works perfectly and so do external wireless mouse. And the touchpad does work without delay in some instances, so it should be capable
- Just from experience the xinput settings in Linux systems don't come as refined as they could be. Sadly.

What I'm doing right now is having xinput list  and in another window a xinput list  and try to make sure the settings are similar.
Will update if I find the right config settings.

Do:
xinput set-prop <# of touchpad> "Device Accel Profile" 0

That did it for me.


Does Hadoop only run on (Ubuntu) Linux server OS or I can run it on desktop?

You can run it on your desktop if you want, people do this all the time with server software, though for testing/production needs you'll probably want to run it on a real server or cloud instance.


Not all the icons have changed after installing a new icon theme in Lubuntu

It depends on the icon theme. If the icon theme contains icons for every mimetype and application, they'd be changed.

To confirm that this, indeed, is the case, download Faenza Icon Theme (it contains almost all the icons) and see if it works.

To install Faenza Icon Theme, open a terminal and run the following commands:

sudo add-apt-repository ppa:tiheum/equinox
sudo apt-get update
sudo apt-get install faenza-icon-theme


Ralink wireles not working for HP dv6 6110

Since the writer didn't wrote the answer down here, i'm writing it, but all credits go to him for that answer. The link is right here


I have the same issue with an XPS 13 9350 and Ubuntu 16.04.
The issue was resolved for a little while when I followed this solution:
Sony Vaio FW350 reboots instead of waking up after sleep/suspend

Now it's randomly back to shutting down instead of suspend.

You can click the suspend button in the top right menu (under the gear icon) while waiting for a solution, although even this works inconsistently on my XPS 13.


Can't log in to facebook accounts using pidgin

Edit: I've noticed that my answer below is outdated. The installation method has changed. Anyone interested in a solution to the problem should just go to the page https://github.com/jgeboski/purple-facebook and follow the instuctions written there. Therefore, my original post is useless now.

The original post:
I ran into the same problem this morning and I've just found a solution here: https://github.com/jgeboski/purple-facebook

It will add new Facebook protocol to Pidgin that works for me.

Go to the page below and download the latest purple-facebook-*.tar.gz
https://github.com/jgeboski/purple-facebook/releases
Follow the steps written on the first page above under Building and Installing on linux and other platforms. It was quite difficult for me to compile it. I had to install some missing programs via Synaptic, I'm not sure which were really needed, however you are going to need libjson-glib-dev for sure. That was the last thing I needed to successfully configure it.
Scroll up to Basic usage and follow the last steps.

That should be it. Please, let us know how it went!


Is there a folder in my home directory where I should put my scripts so they are available from any directory?

I add PATH=/home/djeikyb/bin:$PATH to my .bashrc, and keep all my scripts in ~/bin.

I think $PATH has greater-smaller::left-right precedence, so I put my personal bin folder first. I use a folder called "bin" because all the other program files are in folders called bin. And I even have a couple actual binaries in mine ;p

Don't forget to reload your bashrc to make changes take effect: $. ~/.bashrc


I think the easiest way is probably a mix of tr (to ensure there's only one space between each column) and cut to grab the 4th and subsequent columns:

$ cat test.txt | tr -s ' ' | cut -f 4- -d ' '
Column4
hello
hello there

If you're certain that all the columns are alligned, with spaces (not tabs), then this is shorter:

$ cut -c 25- < test.txt
Column4
hello
hello there

And the obligatory awk solution:

$ awk '{ $1=$2=$3=""; print $0 }' < test.txt
   Column4
   hello
   hello there

Note the whitespace at the start of each line of output, compared to the previous two solutions.


Need more info. What is your goal? Is your VPN server also your LAN gateway? Are you only going to need access to the subnet your VPN will reside on?

ie. Small office with ISP modem/router providing network on one subnet  or
    Large office with multiple gateways/switches/routers/subnets

etc..


I found an article that may be useful: https://help.gnome.org/users/gedit/stable/gedit-spellcheck.html.en

This states that you can Define the language to use for spell checking

By default, gedit will use your current language to spell check your document. If you need to use another language, choose Tools ▸ Set Language…, then choose the language you want to use.

EDIT: Sorry, I overlooked that a bit. I think you need to install dictionaries for them to show up in Tools > Set language menu I believe the languages will show up after you install the myspell-nl dictionary using System > Administration > Synaptic Package Manager


Lock keys panel indicator for MATE Desktop

Native Solution

It turns out that MATE-Tweak, built into the default installation of Ubuntu MATE, has an option to enable keyboard LED indicators

Under Interface, check the box Enable keyboard LED

And now you have three key lock icons in your indicator panel - one for each key. Here's what it looks like when Caps Lock is on but the other locks are off:


App indicator not showing properly (Sigram)

In my case installing libappindicator1 fixed it.

sudo apt-get install libappindicator1


Package CLI service in AppImage or Flatpak?

"Does AppImage have anything similar?"

Yes, it is no problem to convert CLI tools into fully working AppImages.

CLI AppImages from the AppImage project itself

The AppImage developers offer several of their CLI utilities which serve to create, update and run AppImages as ready-made AppImages:

appimaged

appimaged. This is an (optional) helper daemon which automatically creates menu entries for every new AppImage which you store in any of the monitored directories:

Download AppImage from: https://github.com/AppImage/AppImageKit/releases

appimageupdatetool

appimageupdatetool. This is a tool which search for and apply automatic binary delta updates to any AppImage which is prepared for this mechanism. (For the update mechanism to be enabled, the AppImage creator needs to have made use of the 'type 2' AppImage format!) You can check if it is enabled by running './my.AppImage --appimage-updateinfo'. To update an AppImage, just run:

appimageupdatetool -d my.AppImage   # describe where update comes from...
appimageupdatetool my.AppImage      # actually apply the update...

Download AppImage from: https://github.com/AppImage/AppImageUpdate/releases

linuxdeployqt

linuxdeployqt. Despite its name, this cannot ONLY be used for Qt applications, but also for others. This tool makes Linux applications self-contained by copying in the libraries and plugins that the application uses. It optionally also generates an AppImage.

Download AppImage from: https://github.com/probonopd/linuxdeployqt/releases

zsync2 and zsyncmake2

zsync2 and zsyncmake2. These two make up the essential tools for supporting the binary delta mechanism for 'type 2' AppImages:

zsync2 does the heavy lifting of downloading the deltas and patching a copy of the existing (old) AppImage into a new one. At the end of the process you downloaded a percentage of the volume of the old AppImage but have the fullly sized two AppImages (old and new) available locally. Then just test the new and keep it (alongside the old or as the only one) if you like it.
zsyncmake2 is the tool which creates a *.zsync file from ANY file (not just an AppImage). So for 'my.binaryfile.exe' it will create 'my.binaryfile.exe.zsync'. That (much smaller) *.zsync file contains the metadata about the main file which will help to identify which byte ranges have changed from the previous version. If both files are now hosted side-by-side, the 'zsync2' CLI utility can figure out which byte-range(s) from the main (new) binary it should request for download in order to update the local (old) binary.
Download AppImage from: https://github.com/AppImage/zsync2/releases

CLI AppImages from other parties

I myself have build a few AppImages for my own use (some of which remain private for now), because they are very convenient for me: I host them on one shared directory on a Raspbery Pi in my home WLAN, but run them on multiple Linux systems where I have the shared directory automatically mounted upon each boot. This also works very well when testing Live CD ISOs.

ImageMagick v7.0.x

ImageMagick v70.x. I'm building new (unofficial, of course!) releases almost daily for ImageMagick7. Hopefully, this will soon be adopted by the ImageMagick developers themselves...

Download AppImage from: https://github.com/KurtPfeifle/ImageMagick/releases

QPDF

QPDF. I've also built QPDF 8.0a pre-releases. Hopefully, it will not be long before the QPDF developer will release his own AppImage builds (you'll have to check here.)

This is also an example how to include your own custom 'AppRun' script into an AppImage. To see all the functionality of it, run the AppImage with the '--usage' flag.

Download AppImage for now from: https://github.com/KurtPfeifle/qpdf-appimage-testing/releases   <== Here, there will still be experimental AppImages available in the future. These will cover current code developments, based on the most recent Git commits, not official releases.

Update: Jay Berkenbilt, the QPDF author has made the first official release of QPDF-8.0.0 which includes an AppImage as the only binary build for Linux. Get it here: github.com/qpdf/qpdf/releases. I recommend you rename the AppImage to qpdf.ai after download (or create a symlink with that name to it). This makes the handling of the (unwieldy for a CLI tool!) AppImage name much easier, and lets you continue to use the (old) distro-provided qpdf just as before. No conflict!

IPP Sample Software

IPP Sample Software. An AppImage with not just one, but four different CLI utilities is the IPP Sample Software provided by the ISTO Printer Working Group (PWG) which showcases the concepts of the Internet Printing Protocol (IPP) and the new IPP Everywhere standard to come. I made ASCIIcast providing a short introductionary tutorial about this software using my AppImage, which you can watch here:

Microsoft PowerShell for Linux

Microsoft PowerShell for Linux. Microsoft is distributing their new PowerShell for Linux as an AppImage. An ASCIIcast about this running on Debian is here:

Download PowerShell AppImage from:  https://github.com/PowerShell/PowerShell/releases


First you open your database that you have created for Magento, then after open the table core_config_data of your Magento database.

Change the two paths values
From:

  web/unsecure/base_url = http://192.168.0.74/training/Magento2.1.7/
  web/secure/base_url = https://192.168.0.74/training/Magento2.1.7/

To:

  web/unsecure/base_url = http://192.168.0.75/training/Magento2.1.7/
  web/secure/base_url = https://192.168.0.75/training/Magento2.1.7/

where training/Magento2.1.7 is my Magento path.


Why can't I connect from Ubuntu laptop to a Win7 desktop thru Cisco AnyConnect?

For Remote Desktop Connections with Windows, you should use the RDP protocol in Remmina (The same used by Windows terminal services and the one used by any Windows installation if Remote Desktop Connections is enabled).

First of all, ensure that Remote Desktop Connections is enabled in your Windows machine. In Windows 7 and following the official documentation at http://windows.microsoft.com/en-us/windows7/allow-someone-to-connect-to-your-computer-using-remote-desktop-connection:

  Open System Properties by clicking the Start button Picture of the Start button, right-clicking Computer, and then clicking Properties.
  In the left pane, click Remote settings.  Administrator permission required If you're prompted for an administrator password or
  confirmation, type the password or provide confirmation.
  Under Remote Desktop, select one of the options to allow connections.

After that, an given that you are in a VPN, double check that you can ping  the Windows7-System from your Ubuntu one. Tipically, unless you set it up, you will only be able to ping the IP.

Last but not least, use the following configuration in Remmina:

Important:

Protocol: RDP
Username: Account on the Windows7-System with enough rights
Password
DOMAIN: If the previous account is a domain account rather than a local one.
If you didn't set it up, do not try to use SSH tunneling.


The best way is to check all the partitions for a file called /etc/os-release. That file identifies the Linux distribution and version. If you're doing it "by hand," you can use any number of lines. If you want a script to do something with the information, you should probably focus on one line. Here's the file from an Ubuntu 14.04.3 installation:

NAME="Ubuntu"
VERSION="14.04.3 LTS, Trusty Tahr"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 14.04.3 LTS"
VERSION_ID="14.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"

Once you've found that file, you can check /etc/fstab on the same partition for identification of additional partitions associated with the installation. In a default Ubuntu setup, these will identify other partitions by UUID values, which you can obtain from blkid, as in:

$ sudo blkid /dev/sdc3
/dev/sdc3: UUID="5028fa50-0079-4c40-b240-abfaf28693ea" TYPE="ext4"

If you use LVM, the /etc/fstab file will most likely refer to logical volumes by device ID, as in /dev/mapper/ubuntu-home. There are other legal formats in /etc/fstab that might be used if you edited it manually, too.

Again, doing this by hand will require some digging about, but it can be scripted if you want to build a tool to piece it all together automatically.


Wrong resolution when setting nomodeset in /etc/default/grub, right when entered manually

Using nomodeset is a tool to get your graphics working properly, not the solution. As such, I wouldn't be worrying about the resolution you're getting.
You need to boot with nomodeset and figure out how to fix your drivers, most likely by either: updating the open-source one (sudo apt-get update && sudo apt-get upgrade) or by installing the proprietary driver (you should be able to do this from the 'Additional Drivers' application that comes with Ubuntu by default).
Good luck!


It is an API issue, GEDIT changed API So most of the gmate plugins are broken

Source


Very slow boot with Ubuntu 16.04 on XPS 13 with SSD

Finaly I managed to reduce booting time to 10s again.

How did I do this?

It seems swap partition was not configured correct during install. I did a fresh install of 16.04 but told it to use the old swap partition which was located at sda5. As mentioned above in my /etc/fstab the line with swap was uncommented. I removed the '#' and the swap was beeing mounted. Nevertheless the boottime did not improve. When turning swap off an on again by executing sudo swapoff -a and then sudo swapon -a I got an error saying cryptswap is not foung.

I checked with the free command if swap is used  while running ram intensive programs. Swap was not used at all.

So I turned swap off with sudo swapoff -a.

Recreated swap sudo /sbin/mkswap /dev/sda5. (sda5 was my swap partition, if yours is another one replace this).

Now I copied the UUID from the terminal output which appeared after executing the command. (if output is: UUID=e933aaa4-620a-4657-a988-71539a2e36ab you want to copy e933aaa4-620a-4657-a988-71539a2e36ab)

I checked fstab with cat /etc/fstab, which gave me:

  #swap was on /dev/sda5 during installation

  UUID=23b67f5b-52cf-4f95-881c-62c2b962ec06 / none swap sw 0 0

  /dev/mapper/cryptswap1 none swap sw 0 0

I removed : UUID=23b67f5b-52cf-4f95-881c-62c2b962ec06 / none swap sw 0 0

(You can edit fstab with sudo nano /etc/fstab.)

So my fstab now looks like this regarding the swap area:

# swap was on /dev/sda5 during installation
/dev/mapper/cryptswap1 none swap sw 0 0

After that I edited crypttab with sudo nano /etc/crypttab' and replaced the UUID with the one I copied in the step above.

Now crypttab looks like:

cryptswap1 UUID=e933aaa4-620a-4657-a988-71539a2e36ab /dev/urandom swap,offset=1$

Finaly I executed sudo swapon -a an rebooted. You need to reboot for this change to take effect, because only when booting will /dev/mapper/cryptswap1 be created.


Set network drive / share as home folder?

Yes, you can do this:

set up an nfs on your host (raspberry for example)
=> https://help.ubuntu.com/community/SettingUpNFSHowTo#Introduction
"remove" your home directory (maybe just rename it for testing), create an empty one at this place (mkdir /home) and mount the nfs to /home
=> https://help.ubuntu.com/community/SettingUpNFSHowTo#Mounts

your should use the fstab method to do the mount on boot.


Installing indicator-applet-complete solved this issue for me:

sudo apt-get install indicator-applet-complete


How do I recover my data from a failing hard disk?

Sounds like a hard disk going bad. I'd keep a close eye on this one.

To test it further, recreate the partition table, partition and format with gparted and try to copy it once more.


In my firewall I do a couple of things to create a proxy between my main computer and my Intranet computers:

In the FORWARD queue, I have something like this:

iptables -A FORWARD -i eth0 -o eth1 -p tcp -m state --state ESTABLISHED,RELATED \
                            -m tcp ! -s 10.10.0.1 -d 10.10.1.2 ! --syn -j ACCEPT

iptables -A FORWARD -i eth0 -o eth1 -p udp -m state --state ESTABLISHED,RELATED \
                            -m udp ! -s 10.10.0.1 -d 10.10.1.2 -j ACCEPT

iptables -A FORWARD -i eth0 -o eth1 -p icmp -m icmp --icmp-type any \
                            ! -s 10.10.0.1 -d 10.10.1.2 -j ACCEPT

iptables -A FORWARD -i eth0 -o eth1 -p tcp -m tcp -s 10.10.0.1 -j ACCEPT

iptables -A FORWARD -i eth0 -o eth1 -p udp -m udp -s 10.10.0.1 -j ACCEPT

iptables -A FORWARD -i eth0 -o eth1 -p icmp -m icmp --icmp-type any \
                            -s 10.10.0.1 -j ACCEPT

I've noticed that having ICMP can help hence that line. If you don't want to support TCP, obviously don't add that one.

My FORWARD definitions don't include any port specification which means all packets are forwarded, whatever the port. Try to add the source and destination port command like:

--sport 38000
--dport 43000

If I'm correct, you have to look at the multiport capability to include a range of ports (something like this: -m multiport --dport 38000-38999, it may be a colon (:) and not a dash (-) between the start and end port specification [so 38000:38999].)

Then in the NAT filter, I add POSTROUTING commands as follow:

iptables -t nat -A POSTROUTING -o eth1 -s 10.10.1.2  -j SNAT --to-source 10.10.0.1

The IP address in --to-source ... has to be on the same Ethernet card but it does not need to be the same IP address. This is practical if you have a static IP address. In my case I actually have eth0 with my static IP address and eth0:1 with 10.10.0.1 and it works!


If you're using Apache, check out mod_rewrite.


Thanks for the help. As ByteCommander has said, You must use an external drive to create a physical volume. You can not use a mounted hard drive. I set up my usb drive into my virtual machine and used gparted to make a new partition table. From there i could make the physical volume.


Why is wi-fi not working with terminal downloading?

Probably u need to go to a browser and change the HTTP proxy to no proxy.
In google chrome, go to settings-> Change Proxy Settings -> Network Proxy
here delete the info and apply it system wide.

Hope this helps ...:)


I'm closing this question as I fixed the situation with the help of a very humble guy named @StephenDaddona. Read comments on the first post for the fix.
Thank you


the first rule for migrating to systemd

At this point, in 2015, it's most likely that someone has already done it.

systemd has been around for some years.  And there has been a whole cottage industry of people writing unit files and publishing them.  GitHub, in particular, seems to attract repositories of collections of service units.

Indeed simply searching the WWW for autossh.service (as a phrase) turns up:

Phillipp Klaus doing this in 2013
Thomaz Fritz doing this in 2014
unknown people doing this in 2013

a template unit

That said, as I've pointed out in several places on StackExchange alone, this sort of migration is not a mechanistic process, and sometimes just robotically translating from whatever one has to a unit file is doing things wrongly, or at least poorly.  In this case, autossh is positively panting to be handled with a template unit, that it is instantiated into actual service units, parameterized by the target name.  So as /etc/systemd/system/autossh@.service, have:

[Unit]
Description=AutoSSH service for a reverse tunnel from %i
After=network.target

[Service]
User=autossh
EnvironmentFile=/etc/%p/%i.conf
ExecStart=/usr/bin/autossh -M 0 -q -N $SSH_USER@%i $SSH_OPTIONS

[Install]
WantedBy=multi-user.target

Create a file named /etc/autossh/other_server.example.conf with, minimally:SSH_USER=joe

All of the usual controls then apply:

systemctl enable autossh@other_server.example — Enable an instance to be automatically started at bootstrap.
systemctl start autossh@other_server.example — Manually start that instance immediately.
systemctl status autossh@other_server.example — See its status.

And yes, the first rule even applies to this.  Searching, one can find that I was beaten to this, by just under a fortnight, by Greg Freemyer at OpenSUSE.


No icons or bars show up in the desktop, after a recent Ubuntu 13 update

Judging by your question only, I can suspect it's got something to do with your graphic card. Please have a look at this thread:

After upgrading to 13.04 Unity interface is not showing


How to remove firefox-dev (developer edition) icon from ubuntu launcher?

In Step 15, you created a desktop file specifically so the software would show up in your launcher: ~/.local/share/applications/firefoxDeveloperEdition.desktop
Simply delete that file:
rm ~/.local/share/applications/firefoxDeveloperEdition.desktop


Recommended setup for live audio / video broadcast

Install vlc. It will accept a variety of sources, recompress them, and make them available over your lan.

This article describes a webcam. Note, tho, that the video source is /dev/video0. If you have a capture card it will probably make itself available via a similar device.

http://xmodulo.com/2013/09/live-stream-video-webcam-linux.html

Mencoder has similar facilities, but is a bit more difficult to get started with due to its command line oriented nature.


Web browsers are not working from GUI but running from terminal with sudo

It looks like you have a proxy configured in Ubuntu pointing to some server that you don't have access. When running Firefox with another user (like root), the proxy settings are not accessible. Take a look at this question on how to change the proxy: Where are the system-wide proxy server settings?


What does the 'Userspace file system' Compiz plugin do?

It just maps compiz options to a filesystem using a FUSE mount. So you can have /foo/compiz/plugins/move/screen0/options/whatever and that lets you get/set the whatever option in the move plugin.

It's entirely worthless and as far as I'm aware has never actually been used for anything. davidr apparently got bored and people keep making sure it compiles so it never gets removed.


Can't delete old /usr files (moving /usr to new partition)

After reading the mentioned answer twice, there is written you should use the following commands

  $ sudo mount --bind / /mnt
     $ sudo rm -rf /mnt/usr
     $ sudo umount /mnt

Therefore use

sudo rm -rf /mnt/usr

and not

sudo rm -r /mnt/usr

as you wrote in your question.

and you should read this ;)

My previous answer, maybe helpful for other readers:

You have mounted a partition at the mount point /mnt/usr. With the command sudo -rf /mnt/usr you try to delete this mount point and that's not possible. To delete the content of the folder use

sudo find /mnt/usr -delete

More about find with

man find


The volume “filesystem root” has only 0 bytes disk space remaining?

Please run:

sudo apt-get autoremove
sudo apt-get clean

to remove unused packages and their cache (ther ewill be some after upgrade). from there, start with finding out what else takes a lot of space on your disk. dsstoefile1 suggested pretty good examples in his link.
there are also few helpful oneliners here:
https://www.cyberciti.biz/faq/how-do-i-find-the-largest-filesdirectories-on-a-linuxunixbsd-filesystem/

I'd start with finding & removal of old ubuntu kernels, because you don't seem to have separate /boot partition and those can take up to few GB on your root partition depending on how long you have your system up and running.


Ubuntu 12.10 doesn't recognize wireless network it's been connected during installation

You could try:

clicking on the network manager icon
Edit connections…
Find the wireless connection and delete it.
Try connecting again.


Is there a way to add an event from the top panel calendar without opening up the calendar app?

The idea indeed is nice. However, this is currently not implemented.
Implementing this yourself would require coding skills. It could likely be implemented by a Gnome Shell extension, that changes the calendar, or that replaces the current pop-up with an entirely new one.
You could file an enhancement issue. Issues for Gnome are maintained at https://gitlab.gnome.org/. Anyone can register and file issues, i.e. bugs, usability issues and enhancement request. However, chances that someone will quickly implement your idea are small, considering the large project and the in comparison limited number of developers working on it.


Chrome and Slack do not render properly after wake from hibernation in Ubuntu 18.04

I just encounter the same problem after installing Xubuntu 20.10 in an Nvidia Optimus laptop.
As you mentioned, the issue with chrome is already addressed in other posts, but no mention on Slack.
For me the solution of Andrew Bruce (based on tiangolo's answer) fixed the issue with Chrome, so I tried the same for Slack and it worked!
Basically, you have to kill the graphic process of each glitched program (I think it applies to all chromium based apps).
The relevant part is pkill -f 'the_process_name \-\-type=gpu-process'.
So for Chrome and Slack the complete script is:
#!/bin/sh

set -e

if [ "$2" = "suspend" ] || [ "$2" = "hybrid-sleep" ]
then
    case "$1" in
        pre)
            true
            ;;
        post)
            sleep 1
            pkill -f 'chrome \-\-type=gpu-process'
            pkill -f 'slack \-\-type=gpu-process'
            ;;
    esac
fi

Which goes in /lib/systemd/system-sleep/fix-glitched-apps and must be executable (chmod +x /lib/systemd/system-sleep/fix-glitched-apps).


If you are using Gnome: Restarting gnome from a TTY can occasionally break things, so the shell is no longer 'attached' to some backends for themes, power management etc (probably). If some action is possible in the Gnome Shell, Alt+F2+r+Enter is usually the easiest way of restarting Gnome.

If you are (supposed to be) using another Desktop Environment (DE), like Unity: You have replaced the DE with another DE...

Either of these should only be temporary, and can be fixed by logging out and logging in again (if possible), or rebooting. If you can't log out etc from the shell, save any work, switch back to the TTY and run this to restart your machine:

sudo reboot

HOWEVER it can also be possible to log out via terminal, you may want to try this first. Restarting the login screen (GDM/LightDM) can also sometimes work - e.g. for systems not using systemd and using lightdm:

sudo service lightdm restart


How to install Huawei Mobile broadband EC306?

Connect the dongle/modem/adapter/whatever-you-like-calling-it and browse through the files on the onboard storage (often shown as a CD-ROM in devices). Do you see any script-file called 'linux'? Select it and right-click. Under 'properties', check 'execute'.

Now, open the file and click on 'run in terminal'.

Share the results.

UPDATE:
Sometimes, the modem storage media fails to mount on Ubuntu systems. Try opening it on Windows (for which they're made for! :-( ). Now, copy all files on it to your Ubuntu system and do as said earlier.

UPDATE2:
[OPTION 1]
The device storage is shown as a flash drive on your system.

Execute the following command in the terminal (all in one line):

echo 'SUBSYSTEM == "usb", SYSFS {idProduct} == " 1506 ", SYSFS {idVendor} ==" 12d1 ", RUN + = "/ lib / udev / modem-modeswitch - vendor 0x 12d1 - Product 0x 1506 - type option-zerocd "'| sudo tee / etc/udev/rules.d/45-huawei1550.rules

After the command file 45-huawei1550.rules appears in the directory /etc/udev/rules.d/  , from which the OS will load the drivers when the modem is connected next time.

Now, disconnect the modem and reboot. Plug the modem. Open network connections and set-up the connection according to your location & ISP.

[OPTION 2]:
a. To install the Linux Driver tool only:
Run the following command in the installation directory:

    `./install $PATH`        (The "PATH" is where the driver directory is)

And then copy usbmod & startMobilePartner files to /bin/

Copy 45-Huawei-Datacard.rules file to /etc/dev/rules.d/

Restart the system and connect modem again.

Good luck.


Unmounted cifs still work. Rmdir returns "Device or resource busy"

Maybe open files are preventing the unmounting process. I'm not sure if that's the correct behavior. I would expect mount will show the network share still mounted.

Run lsof +D /mnt/storageHDD/MySQL/data/netMNT to list the open files in your mountpoint, then you can try to kill the associated process.


Migrating /home to new hard drive after old one died, root on separate drive

You need larger disk with enough space to hold the image for this operation but it will save you time and other problems:

connect old hdd and mount it in read only mode, then cat the old failing disk onto a bigger disk (normally you would do that with dd but cat also works and is way faster). The image will serve as a backup. You can do that with:

cat /dev/sda > /home/user/failing_hard_disk.image

(I assume /dev/sda is your failing hard drive in this case, but it will be definitely different letter at the end if it's not main drive anymore)

Connect the new HDD
cat the image back onto the new connected drive:

cat /home/user/failing_hard_disk.image > /dev/sdd

(I assume /dev/sdd is the new drive you have connected, this operation will override EVERYTHING you have on new disk, so if you have precious data there, copy them somewhere else before running this)

use gparted to resize the remaining space on /dev/sdd (in casse partition sizes do not match the new disk)
disconnect failed drive (you can also disconnect it right after making the image, doesn't matter, we stopped using ti right after the image was made)
reboot and change bios to boot from new disk

You computer will now behave EXACTLY as it did before (same disk contents), well except it will not fail anywhere soon.


How does one change the default directory for R version 3.0.2 to a user specified directory in Ubuntu 14.04?

You can set R's working directory by… changing the directory from where you run it from. So

cd /foo/bar
R

will start R in /foo/bar.

If you want to always start R in a particular directory, you can change the working directory in the application starter. To achieve that, you need to create a copy of the application starter /usr/share/applications/R.desktop in your user application starter directory ~/.local/share/applications/ and add a line starting with Path= and then insert the desired path name.

Short example for the command line:

echo "Path=/foo/bar" | cat /usr/share/applications/R.desktop - > ~/.local/share/applications/R.desktop


Error while installing libX11-devel, package cannot be found

You can install libx11-dev package using the command sudo apt-get install libx11-dev, instead of libx11-devel.


Why is sudoers NOPASSWD option not working?

You should put that line after the line with the rule for the sudo group, because, as the sudoers man page states:

   When multiple entries match for a user, they are applied in order.
   Where there are multiple matches, the last match is used (which is not
   necessarily the most specific match).


Auto mount a drive that located on Ubuntu and auto share that drive for Window

I divide it into two parts:

1). Mount the drive at boot time:
    * sudo vi /etc/fstab
    * then add this line:  /dev/sda3    /media/lnxBackUp  ext4  users,user      0  0
      In my case, sda3 is the drive that I would like to mount and ext4 is the partition of sda3.

2). Install samba server:
    * sudo apt-get install samba
    * sudo vi /etc/samba/smb.conf
      then edit its config file by adding these information at the end of the page:
    [lnxBackUp]
          writable = yes
          path = /media/lnxBackUp
          guest ok = yes
          create mask = 0777
          comment = Backup drive
          directory mask = 0777
    * Create a folder in /media
    * sudo mkdir /medir/lnxBackUp
    * sudo mount -a

Now, you can access a drive shared (lnxBackUp) from Window.

cheers


Where does gedit store it's plugin configuration and preferences?

From my backup, I found the file I need at [backup-tape]/.config/gedit/saved-session.xml, then I re-installed the gedit-plugins package and enabled "Session saver" plugin.


Ubuntu 13.10 Won't Recognize [or connect] to my Galaxy S3 [Android]

On your Android setting, search for USB Connection Mode, set the connection mode to MSC. Ubuntu should be able to recognized the micro SD card from your Android device and mount it automatically.

*Note: You can't access internal storage while in MSC mode.


Yes, it is possible. No, it is not very advisable.

Linux can read NTFS, however NTFS does not support the Unix-like permissions. This results usually in all files on an NTFS drive having the same exact permissions determined on mount time. This can be deadly for configuration files in the home directory (because, for example, some of them must be unreadable for everyone except the user), and is not very convenient in general.

NTFS with Linux is fine as a storage for large media files (music, videos), backups (with Dejadup), but not very suitable for development, and unsuitable for home directories.


Bad signature on verifying the 18.04.5 sha256 checksum

A new signature file SHA256SUMS.gpg has been posted on August 17th to the Ubuntu 18.04.5 LTS (Bionic Beaver) page.
The file SHA256SUMS.gpg was last modified on 2020-08-17 12:28 with the size of 833.
Now the verifying process is OK.


How to Update Many Symbolic Links at Once

This question should probably be under unix/bash, but here you go:

#!/bin/bash

# renl: Rename links

# Make sure we have at least two arguments, the source and destination
if [ $# -lt 2 ];then
    echo Usage: renl SOURCE DEST [TARGET]
    exit 1
else
    export SOURCE="$1"
    export DEST="$2"
fi

# Setup the target directory argument
if [ -n "$3" ]; then
    export TARGET="$3"
else
    export TARGET="."
fi

# Output the input values
echo "Source: $SOURCE"
echo "Destin: $DEST"
echo "Target: $TARGET"
echo

# Loop thru all links in the target directory
links=$(find $TARGET  -maxdepth 1  -type l)
for f in $links; do
    tolink=$(readlink "$f")

    if [[ $tolink == *"${SOURCE}"* ]]; then
        newlink=${tolink/$SOURCE/$DEST}
        echo "$f --> $tolink ==> $newlink"
        # Uncoment the next line to actaully do the rename
        # rm "$f" && ln -s "$newlink" "$f"
    else
        echo "$f --> $tolink"
    fi
done;

unset SOURCE
unset DEST
unset TARGET

Note that you'll have to input any wildcards for TARGET with single quotes around it if you don't want the shell expansion.


How to import settings of opera from windows 7 to 11.10?

Opera has a sync functionality, called Opera Link. It will synchronize your Bookmarks, Passwords and Speed Dial online via an Opera Account. You can use this to safely upload your settings in Windows and then download by signing in to the same Opera Account in Ubuntu.

In addition to your Bookmarks, Passwords, and Speed Dial, it will also synchronize you Notes, Typed browser history, Search engines, and Content blocker rules. You can individually disable synchronization of any of these individually during the setup process.

Learn How To Use Opera Link


thanks to Doug Smythies,
ubuntu 16.04 is the only one i have ever used.after installed fail2ban,iptables -S output:
    -P INPUT ACCEPT
    -P FORWARD ACCEPT
    -P OUTPUT ACCEPT
    -N f2b-sshd
    -A INPUT -p tcp -m multiport --dports 22 -j f2b-sshd
    -A f2b-sshd -j RETURN

im expecting fail2ban@ubuntu 20.04 have the same behavior.


Snap: how to disallow a connection/interface/plugs by default for all newly installed snap packages?

This is not currently possible, but has been suggested in the forum:

  ...while I understand why x11 and home are automatically connected (lots of apps would have a poor experience otherwise), I’d like to override that for my own machine: upon install, I’d prefer if such interfaces weren’t automatically connected, and I could connect them if I wanted to.

Unfortunately it appears that this idea has not left the discussion stage.


creating a file with the content of a folder

I would do it by

ls /path/to/folder > outputfile

If you want to see the recursive contents of folders within folders with file permissions, you can use

ls -lR /path/to/folder > outputfile


Netplan on Ubuntu 18.10 (Cosmic Cuttlefish): DHCP4 + static routes

After new research I was able to find that my issue is an animal (a bug to be specific).

https://bugs.launchpad.net/netplan/+bug/1781652
https://github.com/systemd/systemd/issues/1850

Routes are applied before DHCP, which destroys them.


Check the publishing history:

  Deleted on 2018-04-02 by Matthias Klose
  remove pgpool2, autopkg test failures with java9, no rdeps


To clone the drive to another drive of the same kind, and with the same size or bigger, you can use Clonezilla (and clone the whole drive). This should not affect other drives.

See this link for more details about Clonezilla,

clonezilla.org

Clonezilla works if you can still read all sectors (at least all used sectors) of the drive.

If there are bad sectors, it is better to use ddrescue to clone the drive. It can save information from 'almost dead' sectors, and sectors near dead sectors. See this link for more details,

sudo apt-get install gddresue

Learn about it at the info page, which contains a lot of good information,

info ddrescue

and follow one of the examples.

Please be aware that Windows XP no longer receives any security updates.


Merging chat history from Windows to Linux (.db to .lock)

The .lock file should only be present when Skype is running.

You can likely just replace the .db file with the one from Windows, but I don't know if the data is 100% consistent across platforms in there. You could also just use the sqlite3 console tool to export from the one database, and then import the resulting data into the existing main.db file on Linux.

However, beware that you may indeed break Skype, and might have to start over.