Why 32bit installation of Ubuntu is recommended?

The 32-bit version of Ubuntu will run on most modern computers, but 64-bit has more specific requirements.  There are a few things that won't run well with the 64-bit version (although these don't seem to be many), so the 32-bit version is recommended just to cover all the bases, I think.  However, if you have a 64-bit computer, odds are that everything you need will run on it and will do so very well.

For example, I was able to get the Linksys AE1000 wireless access point to work just fine with my 32-bit Ubuntu, but when I changed to the 64-bit version I could no longer get the AE1000 to work.  (Perhaps there's a fix but I was never able to find it.)  However, that wasn't a big deal for me, and overall the 64-bit version feels a bit faster and it really runs everything else I've tried.

And although the 64-bit version is called AMD, it works as well on Intel 64-bit processors.


The entire User Interface freezes/becomes unresponsive for up to 20 seconds

The problem seems to be fixed ---> I installed Gnome as my desktop (instead of Unity) and Sublime menus no longer freeze.

I typed this in terminal:

sudo apt-get install gnome-session-fallback

...then:

After the installation is complete, log out of your current Ubuntu session. From here, click Ubuntu icon in the top right corner of the login screen. You’ll be presented with options for all currently installed desktop environments. The latest addition to this list will be Gnome Classic. Click this option, and select OK to be prompted for your login credentials. When you have logged in, the Unity interface will be gone and you’ll be back to the way Ubuntu used to be (Gnome).

Found the solution at:
http://www.geek.com/chips/dont-uninstall-ubuntu-just-change-the-interface-1542514/


Problem installing Ubuntu in my new computer

I found the answer. Starting the installtion in nomodeset. Aparently its an issue with NVIDIA cards.


How to monitor multiple ports with blackbox exporter?

You can specify the port in the list of targets. Take the official example:

scrape_configs:
  - job_name: 'blackbox'
    metrics_path: /probe
    params:
      module: [http_2xx]  # Look for a HTTP 200 response.
    static_configs:
      - targets:
        - http://prometheus.io    # Target to probe with http.
        - https://prometheus.io   # Target to probe with https.
        - http://example.com:8080 # Target to probe with http on port 8080.
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 127.0.0.1:9115  # Blackbox exporter.

You can just specify one target for each port like:

    static_configs:
      - targets:
        - http://example.com:1234
        - http://example.com:4567
        - http://example.com:8901

This example uses the http_2xx probe, but same applies to other probe modules too.


Touchpad not working on Fujitsu UH552 after upgrade to Ubuntu 16.04

I have this similar problem. But it happened after I did a recent update for my 14.04. Did some search on internet and found this fix, may be you can try.
Go to TERMINAL and type this command:

sudo apt-get install xserver-xorg-input-synaptics
sudo reboot

this fix is taken from the forum (more similar to you case): Here


How to get custom desktop file to be the default program for certain files

OK, Solved it!. The problem was with the desktop file. in the exec line, I had to add a %f for nautilus to show it in open with menu.
Exec=/home/thekindlyone/projects/vlcwrapy-nix/vlcwrapy-nix.py %f
Here is a video demonstration, if anyone is interested.


Erlang error: while loading shared libraries: libncursesw.so.6

I think you need to also install the libncursesw5 package:

sudo apt install libncursesw5 libncursesw5-dev

Then try running the command that gave you the "error while loading shared libraries".

Update: If you have these packages and still get the error, it's probably because your software expects version 6 of libncursesw, but only version 5 is available in Ubuntu. (see https://bbs.archlinux.org/viewtopic.php?id=202562 , which is the same problem, but on Arch Linux.)

As a hackish possible workaround, you could create a symlink so your software thinks version 6 is installed, even though it's actually using verison 5:

sudo ln -s /lib/x86_64-linux-gnu/libncursesw.so.5  /lib/x86_64-linux-gnu/libncursesw.so.6

It's not the most elegant solution, but it might work. If you choose to do it, please remember to document it somewhere just in case you run into any problems when upgrading Ubuntu later on.

Please let me know if this was helpful or if you have further questions.


Folders missing in Home using Nautilus-root

When you run nautilus as root (not recommended at all) it uses /root as home directory. So to access the home directory of your standard user navigate to File System/home/<yourUser>.


"Command not found" message while executing "hadoop namenode -format"

In your ~/.bashrc, instead of writing

export HADOOP_INSTALL=/usr/local/hadoop

change it to

export HADOOP_INSTALL=/usr/local/hadoop/bin/hadoop

I was facing the same issue for a long time. This worked for me.

Or try this:

/usr/local/hadoop/bin/hadoop namenode -format


same thing happened to me when i installed lubuntu-desktop alongside gnome on ubuntu 20.04 . I configured it lightdm as the default display manager to run on boot
It showed me  a strange lock and login screen and it was almost impossible to type password from my physical keyboard so I had to use the useless screen keyboard .
try reinstalling ubuntu desktop
steps :

boot into recovery mode and run the following  commands:
 sudo apt update
sudo apt autoremove ubuntu-desktop
 sudo apt install ubuntu-desktop
note that: set the display manager to gdm3


Postgres createdb is not working in Ubuntu 14.04

After some more hours, it seems I found the solution:

  sudo -u postgres psql

  CREATE ROLE username CREATEDB LOGIN PASSWORD 'password';

I basically created a user with privileges of database creation and login.


How to access Ruby on Rails Assets from a Host Machine

In your config/environments/development.rb file, you need to set the config variable, asset_host, that tells the app where to load the assets. For example if your ip address of your local host is http://10.0.2.15:3000 then

config.asset_host = 'http://10.0.2.15:3000'


On a Persistent LiveUSB installation, user ubuntu cannot access /usr/bin/node

Giving the access rights for the file node is not enough.
The user ubuntu must have the 'x' permission for all directories leading to node i.e.

    /root
    /root/.nvm
    /root/.nvm/versions
    /root/.nvm/versions/node
    /root/.nvm/versions/node/v8.8.1
    /root/.nvm/versions/node/v8.8.1/bin


Since 12.10

dpkg --remove-architecture i386

to get rid of multiarch on an amd64 installation. In case you will have message, like:

dpkg: error: cannot remove architecture 'i386' currently in use by the database

you should remove all i386 packages before:

dpkg -l | grep i386


Why isn't the interface shown in the Virtual Network Editor?

The eth0 interface is shown as VMnet8. To set up a static IP address on NAT, VMware Workstation's documentation says that you must use an address ending somewhere in 3 to 127.

To change the address to static, you can follow the instructions on an answer to a question about setting up static IP addresses on Ubuntu (which I've modified below to better suit you):

  Edit /etc/network/interfaces to reflect something like this:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.59.3
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.59.2
dns-nameservers 192.168.59.2

  Then do a:

sudo /etc/init.d/networking restart

Change 192.168.59.3 to other addresses up to 192.168.59.127 for other virtual machines that need a static IP address.


Another option is to use Imgburn in WINE. I have tried it myself and I have yet to run across a bug. (At least in Wine 1.6) Note that if you do end up getting Imgburn, DO NOT run the default installer, as it comes bundled with adware. Instead, use 7-zip to open the installer EXE and extract the actual program. Just FYI - the actual program is completely legitimate and safe. It's just that the installer it's bundled with uses OPENCANDY.

Once you have Imgburn up and running, you'll find it to be a very powerful program.

You will need to mount the ISO to the file system and extract the contents (note that you do not use Imgburn for that part), and then copy the contents of the ISO into a folder of your choice. Once that's done, you can modify whatever files you need to. After you've done that, you can use Imgburn to rebuild it into an ISO. You'll need to specify the boot sector file as the etfsboot.com file found inside the ISO:


Openstack new instance - could not find capabilities for domaintype=kvm

I've resolved using the suggestion presents on this post and this one

As reports this post, I've edited the my KVM Nodes via virsh utility:

$: sudo virsh edit compute-node01-vm

Change the lines below from:

<cpu mode='custom' match='exact' check='full'>
  <model fallback='allow'>.......</model>
  ......
  ......
</cpu>

To

<cpu mode='host-passthrough' match='exact' check='full'>
  <model fallback='allow'>.......</model>
  ......
  ......
</cpu>

Then I've restart all the nodes from MAAS for the changes to take effect. And now I can add a new instance on Openstack


Are you using mysql-server-5.1 from ubuntu repos?

In the file /etc/init/mysql.conf you will find some line like the following:

start on (net-device-up
          and local-filesystems
          and runlevel [2345])
stop on runlevel [016]

Moving the '2' from start to stop should do the trick:

start on (net-device-up
          and local-filesystems
          and runlevel [345])
stop on runlevel [0126]


Installing Ubuntu 12.04.3 on win8 64 bit machine

Then you should try wube for windows as a last option if you need it so badly.
I installed ubuntu by CD but after updates it dosn't boot on start-up. And then I finally used wube it has some pitfalls also.
http://ubuntu-with-wubi.blogspot.com/2011/05/installing-wubi-common-problems.html


one of dual monitors not showing correct resolution by default

see this link..
12.04 did not work, then 13.10 did work but now 14.04 does not work

link is here: https://bbs.archlinux.org/viewtopic.php?pid=1404557#p1404557


i think your grub is installed on your Ubuntu disk. And as you have no plans to reinstall Ubuntu i suggest you to use windows bootloader use windows rescue disk or windows installation disk and run "fixmbr" or "bootrec /firmbr" or similar command to fix your boot record


Installation with WUBI is asking to boot from live CD?

Uninstall Ubuntu By Going in Add and Remove Programs in Windows.  Try again to Install Ubuntu.


Please switch to nvidia. They do work well in 17.10.
nouveau was very sluggish for me too.


Answering my own question.

Use the command php "%f". It should automatically run it in the little window on the bottom.


This will happen when the user's entry is missing from /etc/shadow (which is normally updated automatically, unless you have been editing /etc/passwd directly).

The pwconv utility will fix any inconsistencies. There is a corresponding grpconv program for the groups in /etc/gshadow.


Installed Ubuntu 15.04 alongside Win8 with something else option in a new partition of HDD. But Ubuntu starts directly without letting me choose an OS

This warning says as well, that you probably  wont be able to boot any other OS:

I would give boot-repair a try:

I would read the Ubuntu help wiki UEFI page as well, as it mentions starting Ubuntu installation in Legacy mode instead of UEFI:

And if that doesn't work for you, read:

Installing ubuntu 14.04 along with windows 8 in legacy mode


If it was a quick access and you immediately left that site, then almost certainly no damage could have been done.

For them to be able to use JS to exploit something on your PC would take much more than just clicking a link.

What could have happened is they could have stolen your cookies, so for safety you can just delete all your cookies and history.

In the future don't just click random links, always make sure where they link to.

Also just be aware, if you notice any sort of random activity on any of your accounts, just immediately react to it.

But you are probably being overly paranoid, it's highly unlikely that anything crucial could have happened just from that.

I'd like to add that if you wanted to protect yourself in the future install uBlock Origin as an addon in your browser, it does much more than just blocking ads and it also prevents most forms of JavaScript and XSS attacks.

If you're using Firefox, which I recommend for your privacy and security, you can also install Multi-account containers, so that you can open different tabs under unique identities, sessions and cookies, so that even if something happened it can't access all of your stuff.

I'd recommend installing those addons if you'd like to go the extra mile.


Adobe AIR install problem, Ubuntu x64 14.04

Of course, after one day of googling, after I posted question - the answer has been found.

Here: http://www.tkalin.com/blog_posts/installing-adobe-air-and-elance-tracker-on-ubuntu-13-10-saucy-salamander-64-bit I've found another set of "before installing adobe air, install these libs" and it worked - unlike tons of those before.

Here it is.

sudo apt-get install libxt6:i386 libnspr4-0d:i386 libgtk2.0-0:i386 libstdc++6:i386 libnss3-1d:i386 lib32nss-mdns libxml2:i386 libxslt1.1:i386 libcanberra-gtk-module:i386 gtk2-engines-murrine:i386

And you have to create a symbolic link to your gnome keyring:

sudo ln -s /usr/lib/x86_64-linux-gnu/libgnome-keyring.so.0 /usr/lib/libgnome-keyring.so.0
sudo ln -s /usr/lib/x86_64-linux-gnu/libgnome-keyring.so.0.2.0 /usr/lib/libgnome-keyring.so.0.2.0

Note for Ubuntu 16.04 +

Instead of the package libnss32-mdns, install libnss-mdns:i386 package. That'll solve the problem of package not found error.


At StackOverflow, there is a question giving a possible solution as part of the question, not as an answer. It is closed as off topic, but it could be the right solution.

Access violation error while using XAMPP? [closed]

If that does help you, I will use it to create a valid answer here.


Can't Shrink Ubuntu lvm2 Partition to Dual Boot

The complexities of lvm2 (man page) requires you go into the lvm2 partition and shrink its filesystem size before you can shrink the lvm2 partition itself, unlike the more user-friendly ext4. That requires you boot from a LiveUSB.

As per https://help.ubuntu.com/community/ResizeEncryptedPartitions make a complete backup of your system and verify the backup matches the source.
Make a second complete backup of your system, then verify the second backup to make sure that backup is also good.
Make a LiveUSB with persistance.
Boot from that LiveUSB and follow the steps at  https://help.ubuntu.com/community/ResizeEncryptedPartitions
Once you have completed the above, then you can follow How do I install Ubuntu alongside a pre-installed Windows with UEFI? to add Windows to your Ubuntu system.


What happened to the 10-second boot milestone for Ubuntu?

That goal was achieved.

It is possible (and has been for a while): my system boots in 12.3 seconds. That includes MySQL so I can forgive them the extra 2.3s. Get a quick SSD as a boot up disk and remove any services you do not really need and you too can get a 10 second-ish boot.

Biggest hurdle during boot tends to be the wireless for notebooks. You can speed that up a little bit with some tweaking.

Mind though that the one thing that happened in between was that Canonical dropped their own start up (upstart) system and Unity so we got the regular "systemd". At that moment they also no longer have any influence on the boot time anymore (besides disabling default services). Besides that hardware also caught up with them: the introduction of SSDs makes tweaking your operating system to start up quicker useless... you never get any noticeable improvement that you get when you use an SSD.


Keyboard shortcut to switch layouts does not switch back properly in many distros

I tested this on Kubuntu 20.10. Even if I couldn't reproduce the exact behavior you describe, I noticed that the shortcut Alt+Space conflicts with other shortcuts specific to the KDE desktop.
The shortcuts you are offered to choose between (at least on the KDE desktop) are XKB shortcuts. When picking such a shortcut, you need to make sure that it works well together with the desktop environment you are on.
Alt+Space seems not to be optimal on Kubuntu. I changed it to Win+Space, and then it worked smoothly.


As the desktop related packages don't change very often, you won't have any side effects. You can safely remove kopete. kdenetwork is just the group package for the network software collection. It is like kubuntu-desktop, linux-image-generic.

kdenetwork filelist


Unable to decrypt LUKS USB stick on different computer

Solution:

You have to chown the usb stick on the computer you want to decrypt it:

sudo chown usertwo:usertwo -R [path to usd stick goes here]

After this, it decrypts without a problem.


Unity sidebar and window frames disappear when I click on an icon with 2 or more dots (multiple windows)

A performed a standard update may fix the issue and then a re-install of unity:

How do I reinstall Unity?

At least one of these 2 steps fixed the issue for me - by that I mean the update may be enough.


Help with Canon CanoScan LiDE scanned PDF Documents

Tesseract OCR

  Tesseract was one of top 3 OCR's in 1995.The development is now handled by google since 2006.It can scan images, convert to text and recognize 40 languages.

To install Tesseract

sudo apt-get install tesseract-ocr

Cuneiform

  Cuneiform is another OCR system.It recognises 23 languages which include English, German, Russian, French etc.

To install Cuneiform

sudo apt-get install cuneiform

Other apps that maybe useful

Ocradjvu
Ocrad
gocr
ocrfeeder
pdf studio 8 series


Is there a way to open synaptic package manager with specific Custom Filter selected?

From man synaptic:

OPTIONS
       Synaptic accepts all of the standard Gtk+ toolkit command line options as well as the following:

       -f, --filter-file=filename
              specify an alternative filter settings file

       -i, --initial-filter=int
              apply the filter with number int at startup

       -o, --option=option
              set an internal option (experts only)

To open synaptic with a specific Custom Filter selected from terminal, you would just do

sudo synaptic -i=? (replace the ? with your filter)

For example to open synaptic with the Broken filter as in the image below, you would just do

sudo synaptic -i=Broken


In the Boot set-up(F2), use "Legacy" and not "UEFI".
Ensure that the boot order is HDD first.
For Acer Laptops, ensure you enable the functioanlity of "F12" from the boot set-up.
Insert the USB stick. Boot from USB stick by pressing F12 and selecting your USB Stick name.
Install Ubuntu to your hard disk as you did, and it will work (hopefully!)


The setting is in CompizConfig > General > Focus & Raise Behavior as so documented. The Window Matching rules are quite important.


"Install new software" button disappeared from Eclipse

I do not have a solution, but I figured out this workaround.

Go to Help/Search
Search for "Install new"
Select "Updating and installing software" from the local search results.
Click on the link by the name "Installing new software"
Here click the first link with the text "Help > Install New Software ..."

This opens up the dialog for installing.
For me this happened today after installing a bunch of plugins from oracle and jboss

Best of luck


What does the /apps/indicator-sound/volume_mute GConf key do?

When checked, the volume is muted by default when you log in.


integer i
i=1

Simple i=1 without spaces is enough.

if [ -z == $response ]
    then
        continue
fi

continue means skip everything in the loop that comes after continue and goto next iteration of loop. I don't think that's what you intended to do.

if [ $response == "q" ]

It's a best practice to enclose variable names in double quotes ("$response") when referencing.

i=$i+1

This will assign 1+1 as a string to $i instead on 2. You can either use
expr:

i=$(expr $i + 1)

or simply use:

(( i++ ))

Your final script will look somthing like this:

#!/bin/bash

i=1

while true
do
    read response

    if [ "$response" == "q" ]
    then
        break
    fi

    if [ -f /var/tmp/UE1_${i}.txt ]
    then
        cat /var/tmp/UE1_${i}.txt
        i=$(expr $i + 1)
    fi

    if [ $i -eq  100 ]
    then
        break
    fi

done

For more info on bash scripting checkout this excellent tutorial: Advanced Bash-Scripting Guide.


There are no tools that let you do this.

Gparted (the de-facto tool to do this in Linux/Ubuntu) will always do its actions in sequence with the official tools for a given file system. After and during every action it will also do checks and rechecks to make certain it all goes as it should go. Even  trivial actions like setting a label are done in sequence.  Gparted FAQ even has a note on Windows:

  7: Is there a maximum to the amount of operations in the list?

  Nope, that is, not one an ordinary human being will ever reach. I
  myself tested it with up to 150 operations and it went smoothly.

  HOWEVER, I think it's wise to keep the amount of successive operations
  limited. After all it's your data which is at risk. Especially when
  doing complex operations (copy,resize) I advise you to take it one
  step at a time.

  When resizing boot NTFS partitions, it is advisable to perform this as a single operation only. After resizing, boot into Windows twice to allow Windows to perform its checking operations.


Open the Terminal program
Enter the command sudo update-grub (which will ask for your login password)

This should regenerate the menu configuration file of grub bootloader, and remove the duplicate entry.


I assume that what you are trying to do is start a complete remote Gnome session displaying  on your local machine. This fails because you already have a local session manager controlling your X server display.

Your options are:

Simply start individual remote applications using ssh -X user@192.168.1.107 xclock
Assuming XDMCP is enabled on the remote machine...

2a. Use Xnest -query 192.168.1.107 -geometry 1024x768 :1 to start a remote login session in a local window.

2b. Use Xephyr :1 -screen 1024x768 -query 192.168.1.107 which is a better X server than Xnest
Also assuming XDMCP on the remote machine, configure your local machine to use the XDMCP chooser instead of the standard greeter on startup.

Enabling XDMCP is simply a case of putting

[xdmcp]
Enable=true

in /etc/gdm/custom.conf and restarting gdm or rebooting (assuming you are running gdm).

If you only intend to run a few applications remotely, then option 1 is simplest and continues to use SSH encrypted traffic, which none of the others do (so they are best only used on a trusted local network).

If you need to so something more complicated, then 2b (Xephyr) is may be better, but I've usually found just using ssh -X ... & for multiple remote applications to be adequate.

If you are doing everything remotely, i.e. the local machine is just a display server and doesn't do anything itself, then you need to look into using option 3, starting the XDMCP chooser instead of the standard login.

PS: As noted in the comments, both Xnest and Xephyr are applications which handle the X server protocol and put the entire session into a window. Xnest uses the functions provided by the local X server while Xephyr handles much more of the server protocol itself so is more robust. They may not be installed by default because the average user wouldn't use them.

PPS: After a little thought it's obvious how to encrypt a Xephyr or Xnest session...

ssh -X username@192.168.1.107 Xephyr :1 -query localhost -screen 1280x1024


Geary does not support POP3, you will need an email server that supports IMAP.

(There's a ticket for adding POP3 support to Geary if anyone's interested in contributing a patch!)


dell lap control display(lid) close option

it's easy ...

sudo gedit /etc/systemd/logind.conf
change the HandleLidSwitch=suspense to HandleLidSwitch=suspense
and don't forget to delete the ' # '
sudo systemctl restart systemd-logind


That header bits/predefs.h comes with libc6-dev-i386 (32bit headers). Try:

sudo apt-get install libc6-dev-i386

Reference: Missing predefs.h


Problem: Ufw Enabled with Deny/Deny, however SSH Inbound still works. Please help

I'd expect that traffic from a remote machine to a VM is going to use the forward policy, not the send or receive policies.

Generally, the input/receive versus forward classification is based on whether the destination address is local to the host. The address of a virtual guest is considered foreign.

Try changing the default forward policy in /etc/default/ufw and see if the behavior changes.


What dangers have the Apt bugs security holes (USN-2348-1) caused?

This is my personal analysis of the CVEs, read this with a grain of salt.

Preface: signing keys

Most repositories digitally sign their packages and lists using such a key. For the official repos, the keys are installed together with the base system. If you manually add a repository either directly by adding it to your /etc/apt/sources.lst or /etc/apt/sources.list.d, then you need to add that repository's key manually:

apt-key adv --recv-keys --keyserver keyserver.ubuntu.com ID

or apt-key add FILEin case you downloaded the key separately.

I'm not 100% sure, but IMHO when using the software center or add-apt-repository, the key is installed automatically.

Ubuntu users that never added a repository (PPA) to their system should have all necessary keys.

Users that actually use repositories without having imported a signing key see a warning along the lines below when installing from those repos:

  You are about to install software that can't be authenticated! Doing
  this could allow a malicious individual to damage or take control of
  your system.

CVE-2014-0487

If a hash in the Release file changes, but the file being referred to by the Release file gets served with a 304 response (http status code 304), apt ignored the updated file and continued to use the old version of the file, even though the old version of the file didn't match the new hash.
Source

If an attacker somehow had managed to make you download a malicious package, said attacker could make your system use the old, malicious, files that had already been downloaded, instead of a more recent file available from the repo.

If you never used repositories without having a valid signing key for the repo, you're probably not affected.

CVE-2014-0488

It was discovered that APT did not properly invalidate unauthenticated data. Imagine that you use an unauthenticated repo. You download / install / ... packages from that repo and only later add a signing key for that repo.

All the data that's already been downloaded is just kept. It is theoretically possible, that you have downloaded forged data, because at the time you were unable to verify that (due to the lack of a signing key). Now apt would be able to verify the downloaded data, but it didn't. (Instead it could also just throw away everything downloaded from that repo and download new, this time - with a signing key present - it could verify the downloads).

If you never used repositories without having a valid signing key for the repo, you're probably not affected.

CVE-2014-0489

There's an option called Acquire::GzipIndexesin apt. This option disabled by default.
Here's what the manpage says about it:

   GzipIndexes
       When downloading gzip compressed indexes (Packages, Sources, or
       Translations), keep them gzip compressed locally instead of
       unpacking them.

The issue was, that if you had set this to yes, then the checksum check was not performed, leading to potentially forged packages being downloaded / installed / ...

Personal note: I could not find if Acquire::CompressionTypes::Order:: "gz"; also skipped the checksum check.

If you never set Acquire::GzipIndexes in your apt.conf, you're probably not affected by this issue.

CVE-2014-0490

You can use apt-get download to download packages. If you do so and do not have the repository signing key, then you download packages which you can't verify the integrity of (because you lack the key). In this case, apt should have warned you that you're doing something potentially unsafe, so you can think twice about installing these packages.
The issue is: apt didn't notice the user.
If you never used apt-get download, you're probably not affected by this issue.

Patches

Click here to see the relevant patchset for Debian.

My statements are purely informational, do not rely on them


How I can know the version of the software included with each release?

You can get a list of all the packages included in the disk images (iso or dmg) just reading the .manifest files, for example:

http://releases.ubuntu.com/precise/ubuntu-12.04.3-desktop-amd64.manifest

This is the file with the manifest with all the packages and versions for precise the ubuntu-12.04.3-desktop-amd64 image. For all the packages included in the release version you can use:

http://packages.ubuntu.com/saucy/

replacing saucy for the codename of the release. Of course, there's also the -updates repositories, but the main one should be sufficient.


How to open GUI applications in multipass container(guest = ubuntu, host = ubuntu)? X-Forwarding

It took me some time to find out how to exactly forward the GUI applications from multipass machines to host, but it turned out to be simple...
First, we need to 'ssh' to our guest machine.
Multipass offers the 'shell' command, which is also a wrapper around ssh. Since we are required to turn X forwarding on, we will use the original 'ssh' command instead.
Since, ssh requires public key, we first need to get those keys and save it to our home repository. The ssh keys are saved in '/var/snap/multipass/common/data/multipassd/ssh-keys'. It turned out that multipass uses same key for all the container initiated, so, we just need to perform this once.

mkdir ~/.ssh/multipassKey

sudo cp /var/snap/multipass/common/data/multipassd/ssh-keys/id_rsa ~/.ssh/multipassKey/id_rsa

Add the key to your grp( replace user with your user name)

sudo chown user -R .

Start the container with the 'name'
(replace it with the actual name)

multipass start name

Find the ip of the running container

multipass ls

Now, ssh into the machine with ip 1.1.1.1 ( replace with ip found above)

ssh -X -i ~/.ssh/multipassKey/id_rsa ubuntu@1.1.1.1

Now, all the GUI applications will be forwarded over ssh to the host machine


First: the efi and recovery partitions were created by Windows.
They are needed for booting systems and recovering Windows.

Second: Unetbootin and other 3rd party tools don't work well.
The USB drive was not configured properly to boot in efi mode.

Use the built-in diskpart tool from within Windows OS.
Open command prompt as administrator and execute:

diskpart
list disk
select disk *
clean
create partition primary
active
format fs=fat32 quick
assign letter=**

Note : * = number of USB drive | ** = select a free drive letter

Mount the ISO file and copy the content to the USB drive.

When booting from the USB drive select the entry with UEFI.

If you still have access to an Ubuntu system you can use the disks tool.
Open it and select Restore Disk Image from the menu on the top right.
Choose the ISO file and the USB drive to write it to and start restoring.


How to disable blinking screen on 12.04 with Gnome3?

Ok, i just fixed this. Switch off the Visual Alerts. Although gnome accesibility button showed it as off but some reason it was not synchronizing with universal access settings.

System settings -> Universal Access -> Hearing

Make sure Visual Alerts is off.


A Javascript error has occurred in the main process VSCode

This was fixed by doing

compiz --replace & (from this question)

and then

sudo killall code

and then re-opening code. It doesn't work if I close the terminal that I used for the first command.


Automatically start JetBrains softwares as root (via plank shortcuts) on Ubuntu 16.04

Jetbrains IDE's have a deployment module that will handle the permissions changes for you so you don't have to weaken security, there is a specific option for "in-place server" that handles your scenario.

https://www.jetbrains.com/help/phpstorm/2016.1/deployment.html


Why Can't I install the Intel Graphics Installer app?

Assuming you downloaded the official genuine not guaranteed to work properly graphics installer from Intel at 01.org, you first do the download, then you go to the dask and type 'intel' at which point the intel-linux-graphics-installer should appear so you can run it, or open a terminal alt+ctrl+t and enter the command

intel-linux-graphics-installer

but before you do this, you should also know how to uninstall the driver should you possibly need to.

From the terminal window that you can get to by pressing alt+ctrl+f1, enter the commands

Try to completely remove your ATI drivers from your system:

sudo apt-get purge fglrx*

Remove your xorg.conf

sudo rm /etc/X11/xorg.conf

Reinstall xorg completely

sudo apt-get install --reinstall xserver-xorg-core libgl1-mesa-glx libgl1-mesa-dri

Re-configure Xorg

sudo dpkg-reconfigure xserver-xorg

Reboot

If you can't get to the terminal as described above, use the recovery mode, and enter the root mode.  Use the command mount -o remount,rw / to get the disk into writeable mode, and enter the commands above.


Bash shell for loop process with two paired variable names

You can loop through the *.shorts and then check for corresponding *.mcep files with:

#!/bin/bash

for i in *.short
do
   base=${i%%?????}
   if [ -e ${base}mcep ]
   then
      echo ${base}.short
      echo ${base}.mcep
   fi
done

I just echoed the *.short and *.mcep names here but you can now use them in commands.


Automatic Login even though it is disabled in Settings. How to turn off?

Maybe this can help, because Kubuntu 15.10 should also use the same DisplayManager as 16.04

Find out what DisplayManager you are using DM-List
(KUbuntu 16.04 is using SDDM)
Then you can open the right configuration file (/etc/sddm.conf)
There you can delete the entry as superuser ([Autologin]
User=john
Session=plasma.desktop)
Auto-Login is off

All information are taken out of

  https://wiki.archlinux.org/index.php/SDDM

I got the right hint at a kubuntu chat from a friendly user.

This answer is a copy of an answer from this question:

Kubuntu 16.04 | How to turn off auto-login after start - GUI not working


Warning: World-writable config file '/etc/mysql/my.cnf' is ignored

There is your problem. You changed persmissions on the file so you could edit it and MySQL refuses to let you use it.

Permissions should be:

-rw-r--r-- 1 root root 3505 apr 22 09:56 my.cnf

Nothing more.


Ubuntu won't display boot process on component video ("comp out") on TV

If you connect a TV through a component video signal, it is is a good secondary monitor, but a lousy primary monitor.

The best thing to do is to hook up both the monitor and the TV, configure the TV from the monitor using system settings - screen display as a secondary screen, shut down the computer, remove the monitor and then boot the computer again.

Disadvantage: as you're using a component video, nothing of the boot process will be displayed on the TV (BIOS, grub, ...) until the video driver loads (login screen) but then it should work normally...

Sorry to be the harbinger of bad news.


Try executing this command:

metacity --replace &

It will make it work if you're using compiz. If you want compiz back, type:

compiz --replace &

and the mouse clicks will work again.

It this doesn't work for you, then try this: How to enable double-click

Finally, it will also be a good idea to check if the same mouse works in another computer.

Hope it helps, good luck!


Ubuntu 14.04 Permission denied when trying to get OpenVPN

You can't write into the /etc/ directory without using sudo.  The guide omits this little fact in many cases.  Notice the first command apt-get update which also won't work without sudo.  I think the guide assumes you are logged in as root.

Modify the command as follows:

gunzip -c /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz | sudo tee /etc/openvpn/server.conf


Install apt-show-versions inside an Ubuntu Docker container

Problem and solution is explain here : https://groups.google.com/forum/#!topic/beagleboard/jXb9KhoMOsk

rm /etc/apt/apt.conf.d/docker-gzip-indexes
apt-get purge apt-show-versions
rm /var/lib/apt/lists/*lz4
apt-get -o Acquire::GzipIndexes=false update

[…]

apt-get install apt-show-versions
The following NEW packages will be installed:
  apt-show-versions
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 29.6 kB of archives.
After this operation, 163 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu xenial/universe amd64 apt-show-versions all 0.22.7 [29.6 kB]
Fetched 29.6 kB in 0s (371 kB/s)
Selecting previously unselected package apt-show-versions.
(Reading database ... 46320 files and directories currently installed.)
Preparing to unpack .../apt-show-versions_0.22.7_all.deb ...
Unpacking apt-show-versions (0.22.7) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up apt-show-versions (0.22.7) ...
** initializing cache. This may take a while **
root@4127ac89e58f:/#


Unable to login from 16.04 GUI but able to login from commandline with su

man useradd:

  "useradd is a low level utility for adding users. On Debian, administrators should usually use adduser (8) instead".

To (re-)enable the functionality of logging in as account2:

Try to reset the password of the second user account -- sudo passwd account2;
Create its home directory and make sure it is owned by it


The grep command expects either a file (or, in the case of -r, directory) name or input from the standard input stream - it's just sitting waiting for you so supply one or the other.

As an alternative to typing the name of the current directory, you can use the shorthand . or ./ i.e.

grep -r "hehe" .

or

grep -r "hehe" ./


How to install a deb package with dependencies on something you have multiple versions of?

Having a python3.4 package available in 12.04 won't be your only problem.

Look at the Debian control file:

Package: python3-tesseract
Source: python-tesseract
Version: 0.9-0.4ubuntu0
Architecture: amd64
Maintainer: FreeToGo <FreeToGo@gmail.com>
Installed-Size: 4261
Depends: python3 (>= 3.4~), python3 (<< 3.5), libc6 (>= 2.14), libgcc1 (>= 1:4.1.1), liblept4, libstdc++6 (>= 4.1.1), libtesseract3
Section: python
Priority: optional
Homepage: http://code.google.com/p/python-tesseract/
Description: Tesseract for Python3
 Python-tesseract is a wrapper class for Tesseract OCR
 that allows any conventional image files (JPG, GIF, PNG,
 TIFF and etc) to be read and decoded into readable
 languages. No temporary file will be created during the
 OCR processing.

python3-tesseract (and python-tesseract) depends on liblept4 which is only available in 14.04+.

My recommendation would be to set up a 14.04 VM or upgrade your system to 14.04 to properly install python3-tesseract.


List all recently changed files (recursive)

Of course. From the directory you are in do:

find . -type f -mtime -7 -exec ls -l {} \;

Add a redirection to it (aka > results.txt to store them into that file).

type f does only files and not directories
mtime -7 does 7 days ago up to now (+7 would be 'older than 7 days')
and it then feeds it to ls to show a long list

You can play with the ls -l part too:

find . -type f -mtime -7 -exec ls -Rl --time-style=long-iso {} \;
find . -type f -mtime -7 -exec ls -R  --time-style=long-iso {} \;

will show a tree like method with directories in between the files in long list (1) or short list (2).


Why are the free space and available space not the same in system monitor?

After some googling I found this post on Launchpad stating the following (first comment):

  The ext3 filesystem reserves an amount of the total space for root. If
  some user (or daemon) fills the disk then a login couldn't be possible
  anymore. So even root couldn't login anymore to fix it. Therefore ext3
  reserves an amount of 5% (default) of the filesystem for the root user
  to prevent it (it doesn't work if root fills the disk).

  Available space is now the total free space including the reserved
  space for root. Free space is the free space that you as a user can
  fill :)

  It is possible to change this with tune2fs (PLEASE consult the manpage
  before using this tool).


Thunar still shows SD card after it's been removed

I just realized the problem was caused by unmounting while a file on the disk still in use. I closed the program that was using the file and problem was solved.


Sounds like a video card driver issue. Try changing the kernel boot options from quiet splash to quiet splash nomodeset.

If this works for you, after you install Ubuntu, you'll have to set it again to boot your fresh Ubuntu install. Once you're in, get an internet connection(using an ethernet cable if WiFi doesn't work) and install proprietary drivers.

Read more: http://blog.js-development.com/2012/01/help-ubuntu-1110-wont-boot.html#ixzz22zGQx3lo


Install vnstat by running this in a terminal:

sudo apt-get install vnstat

Once installed, run vnstat in a terminal to show your internet usage.

Example output:

                  rx      /      tx      /     total    /   estimated
eth0:
   Jun '13     14.40 GiB  /    1.70 GiB  /   16.10 GiB
   Jul '13      3.57 GiB  /    2.55 GiB  /    6.12 GiB  /   40.44 GiB
 yesterday    968.58 MiB  /    2.26 GiB  /    3.21 GiB
     today    377.88 MiB  /   26.73 MiB  /  404.61 MiB  /     582 MiB

Source: https://superuser.com/questions/615958/how-to-track-internet-usage-upload-download-on-linux


How do I add parameters to programs launched from Lubuntu's Application Launch Bar?

In addition to the modification made to lubuntu-rc.xml, you will need to edit your terminal desktop file:

gksudo leafpad /usr/share/applications/lxterminal.desktop

Look for the Exec= line and replace with Exec=lxterminal --geometry=148x30.

It appears that logging out and in is needed to make this change take effect. (To give effect to changes in lubuntu-rc.xml, one just needs to run openbox --reconfigure from a terminal.)
Now, the terminal will have the same geometry, whether invoked by the keyboard or via the Application Launchbar.


Ubuntu 14.04 shutdown and restart missing

The solution

You can try resetting your dconf settings by running the following command:

dconf reset -f "/home/yourusername/"

Note the trailing slash, it's important.

Backup:

If this doesn't work for whatever reason, try running:

rm -rf ~/.config/dconf/user

How it works

dconf contains all of the relevant infomation about controlling Unity. It contains menu actions, dock associations, and many different things. Clearing it forces Unity to rebuild all  of it's configs. However, clearing this (while it may fix your problem) may result in the loss of your Unity personal settings. Be careful please!

(src)


Your script is basically setting few environment variables (the export statements) before calling the "python for android" from this location:

/data/data/com.googlecode.pythonforandroid/files/python/bin/python

with the arguments $@ passed to your shell script.

See this page for the meaning of $@.


Where is the default runlevel on Ubuntu 18.04?

In current Ubuntu versions systemd is used as init system.
It uses "target" term for runlevels.

Ubuntu has several targets:

$ systemctl list-units --type=target --all | cat
  UNIT                   LOAD      ACTIVE   SUB    DESCRIPTION
● all.target             not-found inactive dead   all.target
  basic.target           loaded    active   active Basic System
  cryptsetup.target      loaded    active   active Local Encrypted Volumes
  emergency.target       loaded    inactive dead   Emergency Mode
  getty-pre.target       loaded    inactive dead   Login Prompts (Pre)
  getty.target           loaded    active   active Login Prompts
  graphical.target       loaded    active   active Graphical Interface
  local-fs-pre.target    loaded    active   active Local File Systems (Pre)
  local-fs.target        loaded    active   active Local File Systems
  multi-user.target      loaded    active   active Multi-User System
  network-online.target  loaded    active   active Network is Online
  network-pre.target     loaded    inactive dead   Network (Pre)
  network.target         loaded    active   active Network
  nss-lookup.target      loaded    active   active Host and Network Name Lookups
  nss-user-lookup.target loaded    active   active User and Group Name Lookups
  paths.target           loaded    active   active Paths
  remote-fs-pre.target   loaded    inactive dead   Remote File Systems (Pre)
  remote-fs.target       loaded    active   active Remote File Systems
  rescue.target          loaded    inactive dead   Rescue Mode
  shutdown.target        loaded    inactive dead   Shutdown
  slices.target          loaded    active   active Slices
  sockets.target         loaded    active   active Sockets
  sound.target           loaded    active   active Sound Card
  swap.target            loaded    active   active Swap
  sysinit.target         loaded    active   active System Initialization
● syslog.target          not-found inactive dead   syslog.target
  time-sync.target       loaded    active   active System Time Synchronized
  timers.target          loaded    active   active Timers
  umount.target          loaded    inactive dead   Unmount All Filesystems

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

29 loaded units listed.
To show all installed unit files use 'systemctl list-unit-files'.

For desktop systems the default is graphical.target:

$ systemctl get-default
graphical.target

You can switch the target whenever you want with systemctl isolate command. The example below will switch to text-based multi-user.target:

sudo systemctl isolate multi-user.target

For details see official Ubuntu documentation and official RedHat documentation.


What will happen to swap partitions after upgrading to Ubuntu 18.04?

For distribution upgrades, the existing swap partition will be reused instead of creating a new swap file. In your case the existing swap partition from 16.04 will remain unchanged and be reused in 18.04.

  You can share swap area with two or more operating systems. To share swap space, create the swap space when you install the first operating system and then when you install the second one, do not create a new swap space, instead just use the first OS's swap space as the mount point for swap space of the second OS.source

For an explanation about the differences between a swap file and a swap partition see this answer.


You can edit the file: ~/.gtkrc-2.0 and add a line like this to define the font and size to use:
gtk-font-name="Archivo,  14"
depending on the app you may need to update the setting here too: ~/.config/gtk-3.0/settings.ini
gtk-font-name=Noto Sans,  10


Can you unencrypt / remove encryption from a user home folder?

Yes, you can. The short and dirty description of how to do it is this:

Copy your files out of your home directory to another (unencrypted)
location.
Move or remove the encrypted home directory out of the
way.
Restore your files.

The actual process is more complicated than this. The Ubuntu Documentation assumes you've already moved your data without telling you how; this description from Virtually Machine shows you how.

In short:

Log in as root.
Move the encrypted home directory so it mounts not on the home directory, but on a directory called Private in your home directory.
Move everything out of the ~/Private directory into ~.
Remove ecryptfs if desired.

See Virtually Machine for more specifics.

I would recommend logging out and back in just after the move: this makes sure everything is updated in your environment and so on.


"(CRON) info (No MTA installed, discarding output)" error in the syslog

Linux uses mail for sending notifications to the user. Most Linux distributions have a mail service including an MTA (Mail Transfer Agent) installed. Ubuntu doesn't though.

You can install a mail service, postfix for example, to solve this problem.

sudo apt-get install postfix

Or you can ignore it. I don't think the inability of cron to send messages has anything to do with the CPU spike (that's linked to the underlying job that cron is running). It might be safest to install an MTA and then read through the messages (mutt is a good system mail reader).


what is the program that convert audio to text

Have you tried to transcript online?
Try this website, very clear and correct text depending on your audio.
Happyscribe


I would suggest using Aptitude.

Aptitude is a TUI (Terminal User Interface) application managing program. It runs in a terminal but it is pretty intuitive to use anyways.

Install aptitude by using:

sudo apt-get install aptitude

in a terminal.
Run aptitude with:

aptitude

You can open up a terminal with CTRL+ALT+T

After you are in aptitude, you can use the / key to search for a package. If it isn't found the first time you search for it, you can use the / key and search for it again to find the next match.
After you have found the package that you want info on, press the enter key. That will bring up info on a package. You can navigate through it by using the up and down arrow keys.


Upgrade with Nvidia graphics card causes continued issues. Should I remove the card for good?

Switching to the nouveau driver in jockey before upgrades is something I have long recommended.

I also always either...

... accept that the proprietary binary driver is going to be buggy for a while after upgrades
... stick with the nouveau open source driver for quite some time after a new release

For more information see Nvidia over ATI: Choosing a video card and At Present Which is the best choice for a Ubuntu graphics card, AMD or nVidia?


LightDM allows only Russian keyboard layout at login

After upgrade to 12.04 I had the exact same issue. Prior to upgrade, Greek (Polytonic) and Finnish keyboard layouts were available. After upgrade, LightDM only showed Greek (Polytonic), which prevented logging in.

I worked around this by changing the password from the virtual terminal (Ctrl-Alt-F1) by logging in and using passwd to change my password to numeric one as suggested by ggis. Then, when logged in to Unity, I reset keyboard layouts to default, re-added Greek and Finnish layouts and ordered them properly. After a few tries, I got Finnish to show up in LightDM.


This will make you get rid off the apt-get error

sudo dpkg --force-all --purge texlive-latex-base-doc


12.10 Blank Boot Screen after Installing Over Windows 7

You might not have grub. I have had no problem with the cd install. try to reinstall with a live cd instead. ?? you can also do a live boot with you live cd and manually install grub. I have not used the usb method, but you can use that if it lets you try it before installing.


How many packages are in the main repository?

You can run the following command line:

for f in /var/lib/apt/lists/*Packages; do
  printf '%5d %s\n' $(grep '^Package: ' "$f" | wc -l) ${f##*/}
done | sort -n

that on my machine show the following output

27433 it.archive.ubuntu.com_ubuntu_dists_oneiric_universe_binary-i386_Packages
 7768 it.archive.ubuntu.com_ubuntu_dists_oneiric_main_binary-i386_Packages
 1944 it.archive.ubuntu.com_ubuntu_dists_oneiric-updates_main_binary-i386_Packages
  664 it.archive.ubuntu.com_ubuntu_dists_oneiric_multiverse_binary-i386_Packages
  632 security.ubuntu.com_ubuntu_dists_oneiric-security_main_binary-i386_Packages
  605 it.archive.ubuntu.com_ubuntu_dists_oneiric-updates_universe_binary-i386_Packages
  167 security.ubuntu.com_ubuntu_dists_oneiric-security_universe_binary-i386_Packages
   67 it.archive.ubuntu.com_ubuntu_dists_oneiric-backports_universe_binary-i386_Packages
   24 it.archive.ubuntu.com_ubuntu_dists_oneiric-updates_multiverse_binary-i386_Packages
   21 it.archive.ubuntu.com_ubuntu_dists_oneiric_restricted_binary-i386_Packages
   13 extras.ubuntu.com_ubuntu_dists_oneiric_main_binary-i386_Packages
   12 archive.canonical.com_ubuntu_dists_oneiric_partner_binary-i386_Packages
   11 it.archive.ubuntu.com_ubuntu_dists_oneiric-backports_main_binary-i386_Packages
   10 security.ubuntu.com_ubuntu_dists_oneiric-security_multiverse_binary-i386_Packages
    6 it.archive.ubuntu.com_ubuntu_dists_oneiric-updates_restricted_binary-i386_Packages
    0 security.ubuntu.com_ubuntu_dists_oneiric-security_restricted_binary-i386_Packages
    0 it.archive.ubuntu.com_ubuntu_dists_oneiric-backports_restricted_binary-i386_Packages
    0 it.archive.ubuntu.com_ubuntu_dists_oneiric-backports_multiverse_binary-i386_Packages


How can I make rm stop asking me for permission?

I would check if your rm is an alias. Typing alias at the command line you will see all defined aliases. I expect something like

alias rm='rm -i'

If so, the alias is probably defined in in ~/.bashrc, so you can remove the alias altogether or change it to suit your needs.

Alternatively, you can remove the alias for the current terminal session using unalias rm.


Inconsistent mouse and touchpad scroll behaviour across applications

I have also faced the same issue. You can use below procedure to fix it. This will apply system-wide uniform scrolling.

On Terminal write: xev -event mouse. You will get one small box and when you bring your mouse into that section you will get a lot data getting generated into the Terminal.
On scrolling up, note the button name, lets say "x" (in my case it is button 5). Also note down the button name on scrolling down, lets say "y". in my case it is "4".
Create a backup of ~/.Xmodmap file by using cp ~/.Xmodmap ~/.Xmodmap.bak.
Do cat ~/.Xmodmap. Output would be like pointer = 1 2 3 5 4 6 7 8 9 10 11 12
In the above output search for x and y and they will be in consecutive position and just swap them.
In my case echo "pointer = 1 2 3 4 5 6 7 8 9 10 11 12" > ~/.Xmodmap && xmodmap ~/.Xmodmap worked. Note switch of 4 and 5.
Now the scrolling will be applied system wide. No need to reboot.

Note: You must undo all the modifications you have made before applying this setting.


Ubuntu HP laptop getting overheated while playing DOTA 2

Please note the following answer is taken from HP themselves, and is not written by me. Please read the whole article before you do ANYTHING.
Information to read:

  WHAT IS OVERHEATING?
  Heat buildup can cause problems for any laptop (notebook). Generally, when temperatures inside the case rise above 35 degrees Celsius (95 degrees Fahrenheit), the risk of damaging important internal components increases greatly. The most common cause of overheating is the accumulation of dust inside the laptop. The electrical components in a notebook generate heat and fans inside the notebook help move the air to keep the components cooled to normal operating temperatures. Inadequate cooling can cause excess heat to build up inside the case which can damage components. The sound of the fan running constantly may indicate that the laptop is getting hot and is not running as efficiently as possible and that there is a problem with accumulated dust clogging the air vents.

Location of vents:

  Step 1: WHERE ARE MY VENTS?
  Most notebook computers have vents located around the case to allow air to flow through the case. If these vents become clogged, or if heat-generating parts become covered with dust, the fan cannot cool the components properly, because the laptop is hot and overheating becomes a problem. Lint and dust accumulation prevents air from flowing around the cooling fan blades and causes the fan to work harder and the laptop to get hot. If there is dust in the vents, you should clean the laptop by blowing out the dust from around the fan and heat shield. This prevents dust from accumulating.
  It is not necessary to open the notebook (laptop) to clean out the dust with the canned, compressed air.
  The following graphics show the dust accumulation on the inside of the laptop, but dust around the fans and heat shield of the laptop can be cleaned without opening the computer.

  Step 2: ENSURING PROPER SPACE FOR VENTILATION
  To decrease the likelihood of overheating problems, ensure the fans on your laptop are able to ventilate properly. Proper ventilation for the system is important for laptop operation. Follow these guidelines to ensure adequate ventilation:
  Keep the laptop upright and on a sturdy, level surface.
  Provide at least 15.25 centimeters (6 inches) of clearance around each vent.
  If the laptop is being used at very high altitudes, above 1500 meters (5000 feet), take extra care to keep the laptop cool. The maximum limit of 35 degrees Celsius (95 degrees Fahrenheit) drops 1 degree Celsius (~34 degrees Fahrenheit) every ~300 meters (1000 feet) of altitude.

  Step 3: UPDATING THE BIOS.
  After releasing a laptop, HP regularly provides updates for the BIOS and other components. Check for BIOS updates and install them using instructions in the HP support document Updating the BIOS.

  Step 4: USING HP COOLSENSE TECH.
  HP CoolSense technology is a feature in some HP notebook (laptop) computers that combines hardware, software, and mechanical design to dynamically manage the temperature of your laptop computer. HP CoolSense uses a motion sensor in your laptop to sense when your laptop is being used in a stationary or mobile setting, and automatically adjusts the laptop performance and fan speed to keep the computer cool. You can set HP CoolSense software to your specifications. For more information, see HP Notebook PCs - HP CoolSense Technology.

  Step 5: PLACE THE NOTEBOOK IN A COOLER ROOM
  If your laptop is overheating, place it in a cooler room. A small difference in temperature might be all that is needed to prevent a component from failing. Move the laptop to a cooler room in the house or office. If this is not an option, continue with the next step.

  Step 6: TESTING FOR HARDWARE FAILURE.
  If overheating issues persist after cleaning the vents and moving the computer to a cooler room, a hardware component might be damaged. Test the computer to see if any hardware, such as memory, the processor, or the graphics hardware, have failed. Most HP and Compaq notebook computers have diagnostic software to verify hardware failures. For more information, see the appropriate document:

Testing for Hardware Failures (Windows 10, 8)
Testing for Hardware Failures (Windows 7)
Checking Your Notebook PC Using the HP System Health Scan for laptops running Windows Vista
If hardware has failed, either replace the bad component or contact HP for further assistance using the Contact Support tab at the top of this screen.


cat /proc/filesystems does not list vfat

Add a line vfat to /etc/filesystems and make sure the file end with a line just containing a * (create the file if it doesn't exist).


I'll give some suggestions that may fix your problem, but it's not very likely. The problem probably is in the graphics card (have you installed the proper drivers?).

Please remember the original settings before changing anything. If one suggestion doesn't work, revert the changes and try another one.

Go to Desktop Effects – KDE Control Module → Advanced and try changing the following settings:

Compositing type
Qt graphics system
Use OpenGL 2 Shaders
Use VSync

(Don't forget to press Apply).

Also go to the General tab and press the key combination that is shown there.
Go to Style – KDE Control Module → Applications and select a different Widget style.

Go to the Fine Tuning tab and change the Graphical Effects setting to Low display resolution and Low CPU


Installing Ubuntu on a new Dell Inspiron 14-5000 laptop with RAID-0

To install, you need to change your BIOS from RAID to AHCI and turn off secure boot.  You'll need to boot Windows into safe mode after making these changes so that it will continue to work, if you want it to.  If you go into the BIOS on boot and you have your flash drive plugged in, you can choose then to boot from the flash drive to install Ubuntu.


How do I make a bootable USB stick from an ISO image? I'm running Kubuntu 12.04

Why are you trying to "burn" an image to a USB stick? "burning" refers to a laser printing a pattern of holes into the surface of an optical medium, which obviously does not apply to your USB stick.

Give Unetbootin a try, it may actually work (it works for Windows 7 as well).

Alternatively, you could just copy the contents of the image 1:1 to your stick.
First, identify your stick with its device name. You can find this information using "Disk Utility" (or search for "palimpsest" in your Dash). It will look like /dev/sdb.

Next, open a terminal and run:

sudo dd if=myiso.iso of=/dev/sdx

Where myiso.iso should be replaced with the path to your image, and x with the correct device letter of your USB stick. NOTE: accidentally entering a wrong device name can result in data loss on other storage media attached, so beware!

Now, your USB drive should contain a 1:1 copy of the image. Try booting it.


How to unlock the screen at the start of the laptop

That is a BIOS / System Lock password. Check with the manufacturer of your laptop about clearing that password.  This password is not controlled by Ubuntu.

Here is a list of defaults:

Award BIOS backdoor passwords:
ALFAROME    BIOSTAR     KDD         ZAAADA
ALLy        CONCAT      Lkwpeter    ZBAAACA
aLLy        CONDO       LKWPETER    ZJAAADC
aLLY        Condo       PINT        01322222
ALLY        d8on        pint        589589
aPAf        djonet      SER         589721
_award      HLT         SKY_FOX     595595
AWARD_SW    J64         SYXZ        598598
AWARD?SW    J256        syxz
AWARD SW    J262        shift + syxz
AWARD PW    j332        TTPTHA
AWKWARD     j322
awkward

AMI BIOS Backdoor Passwords:
AMI         BIOS        PASSWORD        HEWITT RAND
AMI?SW      AMI_SW      LKWPETER        CONDO

Phoenix BIOS Backdoor Passwords:
phoenix     PHOENIX     CMOS        BIOS

Misc. Common Passwords
ALFAROME    BIOSTAR     biostar     biosstar
CMOS        cmos        LKWPETER    lkwpeter
setup       SETUP       Syxz        Wodj

Other BIOS Passwords by Manufacturer
Manufacturer    Password
VOBIS & IBM     merlin
Dell            Dell
Biostar         Biostar
Compaq          Compaq
Enox            xo11nE
Epox            central
Freetech        Posterie
IWill           iwill
Jetway          spooml
Packard Bell    bell9
QDI             QDI
Siemens         SKY_FOX
TMC             BIGO
Toshiba         Toshiba


Call scripts in directories relative to main script

You can get a script file’s directory by running

echo "${0%/*}"  # or
dirname "$0"

in the script, so just change the lines to

bash "${0%/*}/scripts/script1.sh"          # or respectively
bash "$(dirname "$0")/scripts/script1.sh"

or define a variable, e.g.

script_dir="${0%/*}/scripts"          # or respectively
script_dir="$(dirname "$0")/scripts"

and use that for the paths:

bash "$script_dir"/script1.sh

In a script, $0 holds the script file’s path in its absolute or relative form depending on how you called it. dirname just extracts the directory name, which is the path of root_directory in your case. The same thing can be done with bash Parameter Expansion: ${0%/*} simply deletes everything from the last slash /, which is the filename. With both ways the path remains an absolute or relative path.

I found the dirname solution on Get path of current script when executed through a symlink • U&L, please upvote this answer (as well ;) if you find it useful.


Ubuntu 11.10 issues with jungledisk desktop

If you are running a 64-bit install, run the following command post install of jungledisk.

sudo ln -s /usr/lib/x86_64-linux-gnu/libnotify.so.4 /usr/lib/libnotify.so.1


Using Mac-style (Option+u) umlaut compositon with IBUS

Well, all you need is to edit the keyboard layout and add a dead key for AltGr+U. Let’s start:

Well, if you use US keyboard layout you need two additional things: right-alt and the dead key.

Let's do this in steps:

1. Backup the current layout:

First of all, make a backup from the US layout, so open a terminal and type:

cd /usr/share/X11/xkb/symbols

sudo cp us us.bkp

2. Open the layout file for editing:

Enter in the same terminal:

sudo gedit us

You can see lines like this:

default
partial alphanumeric_keys modifier_keys
xkb_symbols "basic" {

name[Group1]= "USA";

// Alphanumeric section
key <TLDE> {    [     grave,    asciitilde  ]   };
…

Now you can make changes in the basic block which begins on the 3rd line here.

3. Enable right-alt or AltGr:

Add the line include "level3(ralt_switch)" which makes something like this:

    xkb_symbols "basic" {

    include "level3(ralt_switch)"

    name[Group1]= "USA";

4. Add the dead-key:

Find the following line:

    key <AD07> {    [     u,    U       ]   };

and change it to something like this:

    key <AD07> {    [     u,    U,     dead_diaeresis       ]   };

(be careful about the *comma* after the capital U).

Now your layout is ready.

5. Save and close the file.

6. Make changes take effect:

Return to the terminal and run the following command:

sudo dpkg-reconfigure xkb-data

7. Log out!

Or if you have more than one layouts, just change the layout once.

Alternatively

you may want to insert additional characters just with a single right-alt hit, i.e. AltGr+U for Ü, AltGr+A for Ä, AltGr+O for Ö, and AltGr+S for ß. In this case, instead of adding the dead-key (step 4) you should:

4. Add characters to the 3rd level:

Add all characters one by one, like this:

key <AD07> {    [     u,    U,     udiaeresis,     Udiaeresis       ]   };
key <AD08> {    [     i,    I       ]   };
key <AD09> {    [     o,    O,     odiaeresis,     Odiaeresis       ]   };
…
key <AC01> {    [     a,    A,     adiaeresis,     Adiaeresis       ]   };
key <AC02> {    [     s,    S,     ssharp       ]   };

Again, be careful about commas and the capitals – they are necessary.

All the rest is the same.


Error message during start up Ubuntu 18.04

The best way to solve that issue is to boot to another Linux (you need to prepare Live USB with Ubuntu) and then open terminal and execute following:

fsck /dev/sda2


Ubuntu Cronjob Samba Permission and restart

Create a script in /usr/local/bin/sambapermissions.sh

#! /bin/sh
chmod 777 /some/file/you/want/to/make/writable
service nmbd restart
service smbd restart

And now create /etc/cron.d/sambapermissions:

5 3 * * * /usr/local/bin/sambapermissions.sh

This will run every night 5 minutes after 3am.

But what is it you want to do? Do you want to have a file to be writable over a samba share all the time? Maybe check out "create mask" and "directory mask", explained in detail here:
Files are read-only after copying over samba


This is a bug that was already fixed in the code base.

There will be a new stable release update (SRU) soon. Updating your snapd once this is out should get rid of the problem.

Sorry for the trouble.


Accidentally rebound shift+Space and now I can't add a space while typing in caps

OKAY.

So after 4 hours of bashing my head against this wall I learned what the output of xmodmap means thanks to a helpful post buried deep in the depths of reddit.

If you, like me, accidentally overwrote one of the actual binds for your keyboard itself, it's a relatively easy fix.

For any other panicked user who has a random key not working, I highly suggest you do what I did:

Open a terminal,

Type "xmodmap -pke > ~/keymap.jackass" to output a full map of all keys and what they do to a vaguely readable text file. Open said file in gedit or your favourite text editor. Keep this keymap handy, you're going to need it.

Next, type xev -event keyboard to capture what happens when you're pushing the keys that aren't working (I did separate-together-separate to make it obvious what was different.) When nothing was visibly different in xev from pressing space or shift-space, I decided to stare blankly at the xmodmap for Keycode 65, which is the space bar. (Xev will tell you the keycode for each key you press. Handy.)

Now, when I looked my trusty keymap.jackass for keycode 65, I found a curious entry, it read "keycode  65 = space NoSymbol space NoSymbol NoSymbol NoSymbol NoSymbol NoSymbol space space thinspace nobreakspace" which may as well have been a foreign language to me. Fortunately there's resources to help you understand that the tabled entries here indicate what happens when modifier keys are pressed with the space bar. The first six entries are:

Key [without modifier]
Shift+Key
Mode_switch+Key
Mode_switch+Shift+Key
ISO_Level3_Shift+Key (AltGr)
ISO_Level3_Shift+Shift+Key (AltGr + shift).

So all I needed to do was get xmodmap to recognise that the second entry (shift+key) should not read NoSymbol but in fact read 'space'.

So, feeling like a hero for solving what would probably take any long term linux user five seconds, I changed my keymap.jackass entry for keycode 5 to read:

"keycode  65 = space space space NoSymbol NoSymbol NoSymbol NoSymbol NoSymbol space space thinspace nobreakspace"

Why did I do it there first? basic logic, with that long of a string I didn't want to miss an entry, so then I copied that line, and entered into my trusty terminal

'xmodmap -e  "keycode  65 = space space space NoSymbol NoSymbol NoSymbol NoSymbol NoSymbol space space thinspace nobreakspace"'

Voila.

Working shift+space.

Don't be like me kids, learn what basic functions of xmodmap are early!

(Edit)Addendum: after reboot my xmodmap setting did not remain. A quick toss of the xmodmap -e command with the corrections into /home//.xinitrc resolved this on reboot. It's still probably not the best workaround but hey, there you have it.


It's probably best to use a built-in solution like eCryptFS or LUKS.  For an explanation about using eCryptFS, see the sites Jorge points to.

LUKS encryption is easy to set up with the GNOME Disk Utility; just tick the encryption checkbox at the bottom of the "format partition" dialog:

The difference between both is that eCryptFS encrypts files (including the filenames), while LUKS encrypts a complete partition under the filesystem level.

Ubuntu can then remember your password when mounting if you want, allowing you to just plug and play on your device after logging in.


There is probably a way to limit the speed at which your wifi connects. This question was already answered.

Perhaps wondershaper will do what you need. It will limit upload and download speeds independently. Quoting from the article:

sudo apt-get install wondershaper

Now issue a command similar to following (replacing eth0 with your interface name):

sudo wondershaper eth0 1024 256

this will limit the download speed to 1024 Kbps and upload to 256 Kbps. Remember that this limit is for all internet traffic i.e torrent, ftp, browsing and any thing else.

If you want to remove these limits use

sudo wondershaper clear eth0


There is a bug report here:

https://bugs.launchpad.net/ubuntu/+source/thunar/+bug/754618

You can try unmounting the directory or a reboot.

sudo umount ~matt/.gvfs


At first we need to install build-tools and dependencies

sudo apt-get install git build-essential autoconf libtool automake intltool \
libtool-bin libglib2.0-dev libgtkmm-2.4-dev libxml2-dev gnome-doc-utils \
rarian-compat

Then clone repository

cd ~/Downloads
git clone https://github.com/tapule/Gelide.git

Configure source and compile it:

cd Gelide/
./autogen.sh
make

This step fails on clean 18.04 LTS I get errors on last stage:

config.cpp: In constructor ‘CConfig::CConfig()’:
config.cpp:31:16: error: ‘build_filename’ is not a member of ‘Glib’
  l_cfg = Glib::build_filename(utils::getGelideDir(), GELIDE_CFG_FILE);
                ^~~~~~~~~~~~~~
config.cpp:33:11: error: ‘file_test’ is not a member of ‘Glib’
  if(Glib::file_test(l_cfg, Glib::FILE_TEST_EXISTS))
           ^~~~~~~~~
config.cpp:33:34: error: ‘FILE_TEST_EXISTS’ is not a member of ‘Glib’
  if(Glib::file_test(l_cfg, Glib::FILE_TEST_EXISTS))
                                  ^~~~~~~~~~~~~~~~
config.cpp: In destructor ‘virtual CConfig::~CConfig()’:
config.cpp:40:13: error: ‘build_filename’ is not a member of ‘Glib’
  save(Glib::build_filename(utils::getGelideDir(), GELIDE_CFG_FILE));
             ^~~~~~~~~~~~~~
Makefile:612: recipe for target 'config.o' failed
make[2]: *** [config.o] Error 1
make[2]: Leaving directory '/home/mate/Downloads/Gelide/src'
Makefile:553: recipe for target 'all-recursive' failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory '/home/mate/Downloads/Gelide'
Makefile:464: recipe for target 'all' failed
make: *** [all] Error 2

So some patch for this code is needed. I reported bug to developer.

But on 16.04 LTS I can move further:

sudo make install

Running it with gelide results in great screeshot:


is SLiM (simple login manager) compatible with 11.10?

Slim hasn't seen any update since September 2005. It may work for sessions that haven't changed since then but it has the following shortcomings:

Does not initialize policykit
Does not unlock the seahorse or gnupg key vaults
Does not start any DBus-related things

In short, if you are going to use desktops in the range of twm, windowmaker, openbox, it surely is a lightweight choice but you will witness serious degradation if you are headed for gnome, kde, unity or xfce.


How do I get a Winbond Wireless Card to work?

As of Ubuntu Lucid Lynx it seems it should work with ndiswrapper. This is the driver you need for it to work in ndiswrapper: Winbond W89C35 driver  (vid:0416 pid:0035). Just follow the Ubuntu ndiswrapper wiki (Source).

Besides that there is nictools-pci  for some diagnostics.

"These tools can help you to diagnose problems with your ethernet cards
or - in some cases - give those cards the final hint, to work in your
network."
It includes: winbond-diag  Diagnostic and setup for the Winbond w89c840 Ethernet cards.


Unable to change pallette settings in dconf gedit terminal

Change the behavior with

gsettings set org.gnome.gedit.plugins.terminal use-theme-colors true

or

gsettings set org.gnome.gedit.plugins.terminal use-theme-colors false

  If true, the theme color scheme used for text entry boxes will be used for the terminal, instead of colors provided by the user.

or reset the behavior with

gsettings reset org.gnome.gedit.plugins.terminal use-theme-colors

An other example, to set the whole color palette use

gsettings set org.gnome.gedit.plugins.terminal palette "['#2E2E34343636', '#CCCC00000000', '#4E4E9A9A0606', '#C4C4A0A00000', '#34346565A4A4', '#757550507B7B', '#060698209A9A', '#D3D3D7D7CFCF', '#555557575353', '#EFEF29292929', '#8A8AE2E23434', '#FCFCE9E94F4F', '#72729F9FCFCF', '#ADAD7F7FA8A8', '#3434E2E2E2E2', '#EEEEEEEEECEC']"

Or the background-color

gsettings set org.gnome.gedit.plugins.terminal background-color "black"

List all available keys with

gsettings list-keys org.gnome.gedit.plugins.terminal


Lets assume that your iso is at /home/user/abc/ubuntu.iso

to move the iso to a usb drive do the following:

Get a shell on your chromebook by hitting ctrl+alt+T
Type shell and press enter to get a proper shell instead of crosh
insert your USB thumbdrive, and type dmesg|tail to see what it is registered as (mine is sdb1)
Make sure that the drive is not mounted by typing sudo umount /dev/sdb1
Copy the iso to the disk by typing sudo dd bs=4M if=/home/user/abc/ubuntu.iso of=/dev/sdb

Wait for it to finish. and now you should have a working usb disk with ubuntu iso on it, ready to boot.


Everything is fine, you're just looking at the wrong values.

Your applications "really use" only 645 MB RAM (-/+ b/c: used) and 7197 MB (-/+ b/c: free) are still available for applications.

The 2443 MB (Mem: used) is the total amount of RAM that your system is using, but including e.g. disk caches and other things which can immediately be dropped in favour of applications, if needed. These kinds of caches speed things like disk access up without having an impact on how much RAM is available for your applications.

On the other hand, those 5398 MB (Mem: free) are truly unused. One could also even say they're currently useless.

More info can also be found at https://www.linuxatemyram.com/


Windows10 - Asrock z170 extreme4 - Dual Boot

First, disable Secure Boot in your firmware. This might or might not be the source of your problem, but it is a possible source of problems, and if you're experiencing some other problem, you might fix that problem and then run into a Secure Boot problem, which might make you think that your fix was ineffective. Thus, disabling Secure Boot is in order. If you want Secure Boot to be active, you can try re-activating it once you've got the basics working.

With that done, you might try booting with a USB flash drive or CD-R version of my rEFInd boot manager. If you can boot rEFInd, it should show you option to boot both Windows and Ubuntu. Test them both. If they both work, you can install rEFInd to your hard disk via the Debian package or PPA. Alternatively, once you've booted Ubuntu via rEFInd, you can install the grub-efi package in Ubuntu and then run grub-install. This will install GRUB to your hard disk, which should work -- but because you didn't boot via GRUB, that's not quite as certain.

Backing up again, the symptoms you report generally indicate either a Secure Boot error or an improperly-prepared boot disk. You say you've tried preparing your USB drive "thousands of way[s]," which of course is an exaggeration. It's possible that you made some fundamental error in all of your attempts; or perhaps your firmware is very picky and you happened to use methods that ran afoul of your firmware's pickiness. In any event, trying (yet) another tool may work.

As I said, Secure Boot is one possible complication. Ubuntu is theoretically compatible with Secure Boot, and in practice it usually is. Some EFIs, though, are picky or buggy. I know of two specific problems that can occur, and which have different solutions:

Buggy firmware -- One computer I own (an Intel NUC DC5427HYE) came with firmware that refused to recognize Ubuntu's Shim. (Shim being a program signed with a key that Microsoft uses for third-party boot loaders.) It should have accepted this key, but because of a bug in the firmware, it didn't. Updating the firmware to the latest version fixed this problem and enabled the system to boot. I've heard of similar problems with some other computers. Such problems are rare, but if you happen to be running into it, updating your firmware (what the manufacturer probably calls a "BIOS") may fix the problem.
Missing Secure Boot keys -- I've corresponded with one person who discovered that his computer had the public key tied to the one that Microsoft uses to sign its own boot loaders, but lacked the public key tied to the one used to sign third-party boot loaders (including Ubuntu's Shim). Thus, this computer booted Windows just fine, but wouldn't boot any third-party tool. The easiest solution in such cases is to disable Secure Boot. If Secure Boot is a requirement, the only option is to take full control of the computer's Secure Boot keys, as described on this page of mine. Taking this sort of control is beyond most peoples' comfort zones, but it is possible.

Both of these problems present very similar symptoms. The easiest way to distinguish between them is to type efi-readvar (this command comes in the efitools package, which you may need to install). Look for the following line in the output:

C=US, ST=Washington, L=Redmond, O=Microsoft Corporation, CN=Microsoft Corporation Third Party Marketplace Root

This line is part of the identification of the public key required to run Ubuntu's Shim, so if it's not present, you're faced with the second problem I identified; but if it is present and an Ubuntu disk boots OK with Secure Boot disabled but not with it enabled, you're probably facing the first problem. Note that the key part of this line is near the end -- namely, CN=Microsoft Corporation Third Party Marketplace Root. The key Microsoft uses to sign its own boot loaders is similar, but reads CN=Microsoft Windows Production PCA 2011. Ordinarily, both keys should be present (along with some others).


Choosing between binary or source Nvidia drivers

The drivers that you download from the Nvidia site are, as you know updated. The drivers you have on the Ubuntu repositories are updated only upon a Ubuntu release or when there is such a huge problem with them that can only be fixed by upgrading the version.

The only way you are going to get updated proprietary drivers for your Nvidia card is by either using the driver downloaded from the site or adding a PPA.

Fortunately the Ubuntu team keeps a PPA where you can get the most recent version of the Nvidia drivers, updated and packed for your system.

You can add it and upgrade your drivers to the same version released by Nvidia using the following commands in a terminal

sudo add-apt-repository ppa:ubuntu-x-swat/x-updates

you can then install / upgrade your drivers using the packages from the added PPA

sudo apt-get install nvidia-current nvidia-settings

Those drivers are updated every time Nvidia releases a new driver version.

The main difference between installing form the Nvidia site, the default packages released with a Ubuntu release or the drivers from the PPA is the support and where to report bugs to.

Another main difference is the way to remove them, the drivers installed via PPA or distributed with and Ubuntu release will be removed with apt-get while the driver provided by the download from Nvidia has it's own removal procedure.


Turn off display after n seconds in shell script

OP wrote:

  just realized it was a very minor syntax error:

( time=$(zenity --scale --min-value=0 --max-value=20 --text="Pls Select Time in(s)") && sleep $time && xset dpms force off )


Boot repair wouldn't recover  files from a crashed pc or deleted partitions. It simply repair the boot-files or it would reinstall the grub on your disk and then update it.

From the boot-repair log, it was clearly shown that there is no Ubuntu partition other than the swap partition.There may be a chance of getting your Ubuntu partition deleted.


Changing screen Brightness with a script

On my laptop I can check the contents of the file /sys/class/power_supply/C1BC/online: if the laptop is plugged in this file contains 1, otherwise it contains 0.

For example,

if [ "1" = "`cat /sys/class/power_supply/C1BC/online`" ]; then
  echo "Laptop is charging/plugged"
else
  echo "Laptop is discharging/unplugged"
fi

Note. As confirmed by the OP, the C1BC part is system dependent.


How to make Shift + Numkeys act as in MS Windows from GUI?

The option is located in the same dialog menu - mate-keyboard-properties → Layouts tab → Options, but named a bit longer — "NumLock on: digits, Shift switches to arrow keys, Numlock off: always arrow keys (as in MS Windows)" (so it is not visible without scrolling):

Notes:
1. What is interesting Arduino IDE 1.8.4 ignores this option (it is some Java-oriented problem).
2. The method above is also suitable for Ubuntu 18.04 LTS MATE.


Ubuntu killing processes when no more RAM is available

This is behavior determined by the kernel.  When the kernel runs out of memory, it reacts poorly and kills the process using the most amount of memory.  On the desktop, this can sometimes be the xserver, another poor choice to kill first.  This shouldn't happen with adequate swap.

If your strategy was to go without a swap file in order to force the OS to use RAM, I suggest you instead have a swap file, and use the swappiness setting to make the OS use primarily RAM.  Find out how to do that here: How do I configure swappiness?

10 is a typical aggressive value for swappiness.  I found that with values less than 10, the OS seemed to prioritized unloading the swap over the actual running of programs.  In other words, when I ran out of memory, things slowed down immensely.  So maybe start with 10, or something close, and see how well it uses the RAM.


Unable to install ubuntu 12.04 on new motherboard

Adding nomodeset to the boot options fixed the problem for me.


There are viruses for most all platforms (the first worm was for DEC VAX) , they are just more common on Windows.  Different platforms are more secure than others, but a virus can typically gain user level security, which is often good enough, on most platforms.  You can actually run Windows without a virus scanner if you keep it patched and are really careful.

Differences from Windows to Linux for viruses: On Linux it is harder for the virus to get root (or system) level access.  But it could probably still access your address book or saved passwords in Firefox (user level access).

Strategy: If you are really careful and know what you are doing you can get away without a scanner.  A good strategy is to have your scanner just scan downloads or if you are bringing a file from another computer on a USB drive or floppy disk (assuming you have one).  If you want you can have it do regular full system scans too.  It is all about how paranoid you are, and how likely you are to get a virus.

For your laptop I would suggest only having the scanner scan downloads and when you are brining files from another computer.  Having it do full system scans can be a battery drain.

A very important element of a virus scanner is having it updated with new signatures, so pick the package that has the best signature updates, and that works best for how you want to use it.


You can desactivate the computer hibernation in your settings. So when you close your laptop he just set screen brightness at 0 and your task keep running. I doing that for download with closed laptop. That work pretty well.


Why are bugs fixed in the development release and then backported instead of porting the fixes forward?

When an Ubuntu version is released, it features get frozen. The updates provided for it is mostly security updates and patches. But major changes of software will not be released (included in the repository) for this release.

That is why the default enabled Ubuntu repositories include security-updates, updates and proposed repositories. The first two repositories include bug-fixes and security updates and proposed is used for testing the newer updates.

Mainly the backports repository's function as said in the Wiki is --

  Backports offers a way to selectively provide newer versions of software for older Ubuntu releases. Most commonly, the Backports team will provide new versions of standalone applications which can be safely updated without impacting the rest of the system.

That means, while it was perfectly valid for Canonical for not providing any newer version of standalone software (major releases), You still have a chance to install softwares which are backported. But these are only provided by backporters and they try their best to ensure that, nothing will break. (but it can break the existing softwares sometimes). That means this is a  best-effort support and that is why it is labeled as unofficial updates in software-source (software-properties-gtk).

In short words, Backports are not provided by Canonical and you should be glad that some developers tried their best and invested time and energy to bring you new versions of the softwares even after the version is freezed.

I think, I have made it somewhat clear.

Also take a look at this thread


Is it possible to display windows which are bigger than monitor resolution?

You can't do that. If your monitor doesn't support a particular resolution, then you can't display an application at that resolution.


How to print PDF files automatically from a directory?

Install the package inoticoming

sudo apt-get install inoticoming

Install the package trash-cli to use your trash folder instead of deleting the PDF

sudo apt-get install trash-cli

If you prefer the deletion of the file via the classical rm, than you don't need this package and you have to replace the line

lpr "$2/$1" && trash "$2/$1"

with

lpr "$2/$1" && rm "$2/$1"

in the script below.
Create wrapper script printpdf

mkdir -p ~/bin
gedit ~/bin/printpdf

Add the code below, save the file and close the editor

#!/usr/bin/env bash
FILE="$1"
if [ "${FILE##*.}" = "pdf" ]
then
    lpr "$2/$1" && trash "$2/$1"
fi
exit 0

Make the script executable

chmod +x ~/bin/printpdf

Watch your folder

inoticoming /path/to/MY-SHARED ~/bin/printpdf {} /path/to/MY-SHARED \;

And as @Rmano said in the comments

  About point 4, notice that is practically impossible to be sure that the file has been printed. You can check it has been sent to the printer, but printed is quite more complex and really never fail-proof (and probably printer-dependent).


Amarok tool tips are just black boxes, Is it possible to fix it?

This is a bug: https://bugs.launchpad.net/ubuntu/+source/gtk2-engines/+bug/144968

Some KDE applications appear to change the theme settings so the tooltip is effectively black-on-black. There is a workaround (mentioned in that bug report) that involves opening the theme settings and changing the tooltip colours back, but this is temporary in that when you next launch Amarok, you'll be back at square one.

The bug suggests that this might only be a Clearlooks engine issue. Perhaps switching to another theme might help (although I realise this is far from ideal).


How to switch/disable functionality of fn keys on Ubuntu - USB keyboard

this is the best solution what i found ;-)


How to add "New Document" option to desktop context-menu?

You can use the Desktop Icons NG (DING) extension. It is an enhanced and maintained fork of the Desktop Icons extension that comes preinstalled with Ubuntu.
The extension provides the New Document option that you want. Other features include (quoting from the extension's GitLab page):

Drag'n'Drop, both inside the desktop, between desktop and applications, and nautilus windows
Allows to use "Open with..." option with several files
When hovering or clicking on an icon with a name too large to fit, it shows the full name
Doesn't hang the compositor when there is too much activity in the desktop folder


How to smooth subtitle fonts in SMPlayer?

After a while I found a solution to this:
 In Smplayer Preferences->General->Video Tab choose for Output driver: opengl or gl, instead of Default or xv


Ubuntu 13.04 mounts iPhone disk spaces and after a while unmounts them

On Ubuntu 13.04 what worked for me with an iPhone 4 and ios 7 is to use a USB3.0 jack.
The USB jacks on the front of a PC are typically 2.0, I could not connect using them.


How to add Gmail account with 2-step verification in Empathy?

When you enable two-step verification on a Gmail account you then need to generate an application specific password for each program you want to access your account. This will be different to your normal Gmail password (which will no longer work on it's own)

To do this log into your Gmail account and then go to the Google account settings.

Click Edit

Type in a name for the application then click the 'Generate password' tab. Copy the generated password and put it in the password box for the application you wish to use with your Gmail.

More information can be found from Google here


System crashes when converting many images in Imagemagick with one command

You have to define pdf page setting.
Type into terminal
convert -page A4 *.jpg xxx.pdf

Where xxx is the file name. There is no limitation of image quantity. But lots of image need more time to generate a pdf file.


Loaded runtime CuDNN library: 7.0.5 but source was compiled with: 7.2.1.

I had this same problem, following approach works fine

pip3 uninstall tensorflow-gpu

pip3 install tensorflow-gpu==1.9.0

Note: I am using 'pip3' because I was working with python-3.x, you can use 'pip' instead if you are working with python-2.x


Why doesn't the authorized_keys file stop SSH from promting me with "The authenticity of the host  can't be established"?

You're confusing verification of a server with its host key (done by the client) with authentication of a ssh user login (done by the server).

The authenticity of the host is verified on the client with the host key. This should prevent possible MITM attacks pretending to be your server. The host keys are saved on the server in /etc/ssh/ssh_host*key and on the client in ~/.ssh/known_hosts file.

Connecting to a server using ssh -vvv shows this:

debug1: Server host key: ecdsa-sha2-nistp256 SHA256:fYR10r/RKXIzOmJYbgbDi29E10oW7MLjto2plpALaBY
debug3: hostkeys_foreach: reading file "/home/xxxx/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/xxxx/.ssh/known_hosts:69
debug3: load_hostkeys: loaded 1 keys from xx.xx.xx.xx
debug1: Host 'xx.xx.xx.xx' is known and matches the ECDSA host key.

Server sends host key
Client searches the key in known_hosts
Client loads and verfies the key

You don't need to manually create the host key, this is done automatically. On the client side you don't need to add the host key manually as this is done on the first connection to a server (You have to type 'yes').

When the host key changes due to new installation of the server you need to remove that key from the known_hosts file, otherwise ssh refuses to connect unless you have the -o StrictHostKeyChecking=no option set which I would not advise to do.

When you added the ssh key from your server to your clients authorized_keys file, you authorize connections from your server to your user on the client which is probably not what you want. I advise you to remove the key on the client side.

Further reading:

What is the difference between authorized_keys and known_hosts file for SSH?


You can install a newer kernel

as described in Kernel/MainlineBuilds or
in this case more simply with the packages built from linux-lts-vivid from the trusty-updates repository:

sudo apt-get install linux-generic-lts-vivid

This meta-package always depends on the most recent version of Canonical's v3.19 kernel branch.

The equivalent for the v4.4 kernel branch of Ubuntu Xenial is linux-generic-lts-xenial (what a surprise).

Since kernel packages of different branches don't replace each other, there is virtually no danger, that either of the above steps will make your system unbootable¹. If the newly installed kernel doesn't run, you can select to boot different/previous kernels in the GRUB menu during boot.

¹ The most notable exception is a broken GRUB configuration. If update-grub (called by the kernel package post-installation and post-removal scripts) doesn't work without the new kernel, it won't work with the new kernel either.


My Lenovo W500 resumes from suspend prematurely

I think my hinge for the display was weak or loose and the open lid event was causing it to resume.  I disabled it with this:

How to prevent resume from sleep/suspend on lid open?


Problem solved.
It turned out that Ubuntu desktop was not installed. So I did

sudo apt-get install ubuntu-desktop

Additionally, I changed a line in

/lib/systemd/system/x11vnc.service

namely

# ExecStart=/usr/bin/x11vnc  -xkb -noxrecord -noxfixes -noxdamage -display :0 -auth guess -rfbauth /etc/x11vnc.pass
ExecStart=/usr/bin/x11vnc  -create -xkb -noxrecord -noxfixes -noxdamage -display :0 -auth /var/run/lightdm/root/:0 -rfbauth /etc/x11vnc.pass -rfbport 5905

After this change, I was able to connect via VNC (from my Mac)


It has been answer by Tim Hoffmann on http://tex.stackexchange.com:

  This is a known issue with Qt 5. See http://sourceforge.net/p/texstudio/bugs/1512/


I have the same problem, caused by UEFI and laptop's specific problem.
Try to format your USB drive into UTF-16, and do other things like this: maybe your situation

But I solved my problem by installing 13.10, and then 12.04. (And then delete 13.10, I know that is bad resolution, but it work for me).


How to boot from a usb-drive with ubuntu installed on it?

This article has a detailed recent tutorial describing the process. Giving it a look might just solve your problem and give you some required knowledge.


How can I kill this annoying text bar at the bottom of every window?

From my research, it appears you can't in Chrome:

http://www.reddit.com/r/chrome/comments/2cxyeq/how_do_i_turn_off_the_status_bar_the_little_bar/
https://superuser.com/questions/239202/turn-off-the-link-hover-statusbar-in-google-chrome
https://productforums.google.com/forum/#!topic/chrome/FtD7qjochgw
https://www.google.com/search?client=safari&rls=en&q=turn+off+status+bar+chrome&ie=UTF-8&oe=UTF-8

I think Firefox has an option to turn it off.


Unable to update Ubuntu 17.04 to 17.10 Hash Sum mismatch error

I connected to another wifi network, this solved my problem.


You can configure sudo to never ask for your password.

Open a Terminal window and type:

sudo visudo

In the bottom of the file, add the following line:

$USER ALL=(ALL) NOPASSWD: ALL

Where $USER is your username on your system.
Save and close the sudoers file (if you haven't changed your default terminal editor (you'll know if you have), press Ctl + x to exit nano and it'll prompt you to save).

As of Ubuntu 19.04, the file should now look something like

#
# This file MUST be edited with the 'visudo' command as root.
#
# Please consider adding local content in /etc/sudoers.d/ instead of
# directly modifying this file.
#
# See the man page for details on how to write a sudoers file.
#
Defaults    env_reset
Defaults    mail_badpass
Defaults    secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"

# Host alias specification

# User alias specification

# Cmnd alias specification

# User privilege specification
root    ALL=(ALL:ALL) ALL

# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

# Allow members of group sudo to execute any command
%sudo   ALL=(ALL:ALL) ALL

# See sudoers(5) for more information on "#include" directives:

#includedir /etc/sudoers.d

YOUR_USERNAME_HERE ALL=(ALL) NOPASSWD: ALL

After this you can type sudo <whatever you want> in a Terminal window without being prompted for the password.

This only applies, to using the sudo command in the terminal. You'll still be prompted for your password if you (for example) try to install a package from the software center