What are the differences between "md5sum" and "sha256sum"?

Short answer: For verifying ISOs, there is no practical difference, use whichever you want, as long as you trust the source providing the sums. MD5 is/used to be the standard, but the computing world is moving towards adopting SHA since it is newer and "better" for the future; hence, SHA sums are often provided as an alternative.

md5sum and sha256sum are programs which implement the MD5 and SHA-256 hash algorithms respectively
In general, a hash algorithm takes an input of any (arbitrary) length and runs mathematical computations on it to produce a relatively small, fixed-length output, called a "hash" (or "sum")
Verifying data integrity (e.g. ISOs) is only one of the many uses for hashes
The primary difference between the older MD5 and the newer SHA-256 hashes is that MD5 produces a 128-bit output while SHA-256 produces a 256-bit output
For verifying data (ISOs) to work, the hash of the data must effectively be unique, so that no other data produces the same MD5 sum or SHA-256 sum.

In theory, this is possible, i.e. two sets of input data produce the same output hash, called a "collision".
The chance of such collisions is lower with SHA-256 compared to MD5 because its 256-bit hash is double the size of MD5's 128-bit hash.
In practice, the chance of a collision when verifying ISOs, even with MD5 is zero given the 100+ MB size of ISOs.

Still, since the computing world is moving towards SHA because it is a newer and "better" hash for the future, ISO checksums are often provided in multiple formats.


mysql -u root doesnt work but sudo mysql -u root does, why?

Access with sudo: sudo mysql -u root -p
Delete the root user: drop user 'root'@'localhost';
Create the root user again: create user 'root'@'%' identified by 'your_password';
Give permissions: grant all privileges on *.* to 'root'@'%' with grant option;
Update permission tables: flush privileges;
Exit MYSQL and try to reconnect without sudo.

Font: can't login as mysql user root from normal user account in ubuntu 16.04


Ubuntu 20.04 - Applications take too long to start up

I've got some older applications (grsync, MasterPDF Editor (since updated), VueScan (since updated) built on GTK2 that have/had the same behavior on 19.10 and 20.04. Installing the packages:

libcanberra-gtk-module
appmenu-gtk2-module

solved the problem for me. Reboot after installation.

If they don't help, you can remove the packages in the usual way.


Startup disk creator not launching in Ubuntu

If you couldn't fix usb-creator-gtk you can try to use UNetbootin.

Or just use CLI utility dd.


"Unspecified error" when connecting camera on 64-bit Ubuntu

I have the same issue on Ubuntu 12.10 (64-bit) with a Canon EOS 400D. I found reports about this only happening when connecting the camera through a USB3.0 port, but not when plugging in the cable to a USB2.0 port; however, this workaround is not working for me with an Asus N76VM laptop. Maybe it works for you.


How to check implementation details of 'watch' command?

In addition.

It is in the procps package.

For example if you search the man pages of ubuntu it will normally say what package provides the code. (Like this)

The source code can be found (here).

Direct Download:
http://procps.sourceforge.net/procps-3.2.8.tar.gz

or you could use dpkg to see what package owns a particular file like so:

dpkg -S /usr/bin/watch

Find source code for any command:

So if say you wanted to look at top source code you could:

whereis top

The binary file for top is "/usr/bin/top" and to find the package that owns that file:

dpkg -S /usr/bin/top

Make sure to:

sudo apt-get install dpkg-dev

And then you can find the source code for a package by:

sudo apt-get source procps
sudo apt-get source gedit
sudo apt-get source <package-name>

It will download a tar in the current directory and extract it:

We should then be able to find the source code for how it works:


How can I know that which apps are eating data usage in ubuntu?

I found out that iftop is a nice option for data monitoring by specific interface.

You need to run the command with sudo.
Use the -i flag to choose specific interface.

Example:
sudo iftop -i <interface>

2.You can use top command to see all the running processes filtered by:
- PID - Process id.
- USER - user that running the process.
- %CPU - the cpu percent the app is using.

You can view these topics for "larger" data usage apps on Ubuntu:

https://superuser.com/questions/615958/how-to-track-internet-usage-upload-download-on-linux
https://www.tecmint.com/linux-network-bandwidth-monitoring-tools/


What is the difference between copying an a.out file(executable file) and installing an application?

Well, when saying installing an application, that normally means that you use a package manager like dpkg or the higher level apt family. In this case, the executables are shipped in a package that also can contain additional libraries that are needed to run the executable, manpages, developer files, configuration files etc. The advantage of this is that the admin can keep track of what is installed and also ensures that when installing new software or updates, the new software does not clash with other software and libraries already installed which could lead to other applications crash.

So, while it might work to just copy over your executable to another system, it is not recommended as it can break things. It is safe to copy executables to somewhere outside the system paths like /bin/, /sbin, /usr/bin, /usr/sbin.
You could use /usr/local/bin and /usr/local/sbin for such a purpose or even better create a directory beneath /opt for your executable and place it there. Then call the executable with the full path or add the path to the executable to your PATH environment variable.

$ mkdir -p /opt/myapp/bin
$ cp myexec /opt/myapp/bin/

$ /opt/myapp/bin/myexec

or

$ export PATH=$PATH:/opt/myapp/bin
$ myexec


the system settings icon disappeard, how to restore it?

Click on the top-left icon ("the dash")

Type System Settings
Click the sole remaining icon:

and it'll re-appear!
To "lock" it permanently to the "launcher" again,

Right click its icon on the launcher
Click Lock to Launcher.

Alternatively, click the tiny gears icon in the top right of the screen, and then choose System Settings and stop worrying that the other icon is gone!  ;-)


fatal error: linux/compiler-gcc7.h: No such file or directory

Here are two issues:

Kernel does not support PIC mode for compiling, details could be traced at this post. As @Joy noted, currently apt installed gcc5+ has PIE enabled by default, we need to add -fno-pie in to gcc option.
Here I am following this fix, add following lines start from L774 of Makefile under the git repo you have cloned.
# force no-pie for distro compilers that enable pie by default
KBUILD_CFLAGS += $(call cc-option, -fno-pie)
KBUILD_CFLAGS += $(call cc-option, -no-pie)
KBUILD_AFLAGS += $(call cc-option, -fno-pie)
KBUILD_AFLAGS += $(call cc-option, -no-pie)

# optional, mute warnings on pointers signedness to speed up compilation
KBUILD_CFLAGS += $(call cc-option, -Wno-pointer-sign)

include/linux/compiler-gcc.h:121:1: fatal error: linux/compiler-gcc7.h, this basically stating that under folder include/linux of the git repo you have cloned, there is no such a file named compiler-gcc7.h. Currently under that folder exists only up to compiler-gcc5.h. Therefore a straight forward approach is to install and temporarily choose gcc-5 as the default compiler. Following:
# install gcc-5
sudo apt-get install gcc-5

# use update-alternatives to switch default gcc version
# register gcc-7
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-7 50
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-5 60

# choose gcc-5 at prompt
update-alternatives --config gcc

# now check gcc version, verify is using gcc-5
gcc -v

## gcc version 5.5.0 20171010 (Ubuntu 5.5.0-12ubuntu1)

Installation instruction stated to install libnl-dev via
sudo apt-get install libnl-dev

yet libnl-dev seems no longer exists for 18.04. Consider use
sudo apt-get install libnl-3-dev

instead if you had trouble.
Finally you could switch back to gcc-7 after installation via
# choose gcc-7 at prompt
update-alternatives --config gcc


Why is the sound not working in Viber Desktop?

I was with the same problem. I fix it changing the "Audio Output" on Viber Settings>Audio & Video.

I hope this can solve your problem too.


configure: error: avcodec headers not found

As you can see here on packages.ubuntu.com, avcodec.h is in the libavcodec-dev package. Use following command to install it:

sudo apt-get install libavcodec-dev


You don't need to specify the version when you install if you want the most updated package.

Command-line method

Do the following on a terminal:

sudo apt-get update

to update your package list with the most recent version of g++ enter you password and press Return and then,
Do:

sudo apt-get install g++

to install g++.

GUI method

You could also install it from the Software Center. Type "Software Center" on the dash and then type g++ in the search bar after software center opens up and then click on install and enter your password.


Installing ubuntu-mate-desktop on 16.04, blueman configure issues

It fails to restart DBUS service when configuring blueman package:

Open for editing /var/lib/dpkg/info/blueman.postinst
Comment one of these line

#set -e

or

#invoke-rc.d dbus reload


I downloaded ubuntu but I also had to download WinZip in order to complete the download?

There is no need to do all that. Just download ISO file from Ubuntu website and then also download Universal USB installer from here Universal USB installer.

Then install it on the Pen drive you want to do so.

You will be able to see these windows when you run this program on windows like this.
For further queries go to Install Ubuntu


how to backup and restore transmission torrents?

There are several things to backup if you want a full backup/restore.
incomplete/complete directories and files.  These should be specified in your transmission-daemon settings.json (location depends on your install but defaults to $HOME/.config/transmission-daemon/settings.json on linux I think).
Your source torrent files may also be getting "picked up" from a watch directory somewhere but you don't generally need to keep these.  If you want to keep these you should back this up as well.  Directory location also specified in your settings.json.  However transmission is often configured to delete source torrent files (from watch dir) after they are added.
The "state" for transmission-daemon is stored in $HOME/.config/transmission-daemon/ so aside from your partial/complete download folders, this is the important folder to grab if you want to resume in-progress downloads after backup is restored on a new install.  Note that $HOME in this case will be whatever $HOME is for the transmission-daemon process and may not be your own user's home directory.  This location can be overridden by starting transmission-daemon with the --config-dir param (see transmission-daemon -h)
[root@some-server current]# find /root/.config/transmission-daemon/ -type f
/root/.config/transmission-daemon/resume/ABC.resume
/root/.config/transmission-daemon/resume/XYZ.resume
/root/.config/transmission-daemon/torrents/ABC.torrent
/root/.config/transmission-daemon/torrents/XYZ.torrent
/root/.config/transmission-daemon/settings.json
/root/.config/transmission-daemon/stats.json

Be warned that the torrent/resume files in the config folder expect the downloads/incomplete files to be in a specific location...so if you change the OS path where you are storing incomplete and complete downloads you will need to start transmission and then tell transmission where to find the files.
For complete (torrent number 3)
transmission-remote -t 3 --find /new/path/to/complete/downloads/
For incomplete (torrent number 4)
transmission-remote -t 4 --find /new/path/to/incomplete/downloads/
If you keep complete/incomplete in the same directory then it is easier as you can update all torrent locations in one go.
For complete/incomplete (all torrents)
transmission-remote -t all --find /new/path/to/downloads/
I found (with Transmission 3.00) that even if you tell transmission where to find the files and see that transmission-remote -t <torrent-id> -i now reports the updated location...there is still an error message about not finding any data.  You need to restart transmission-daemon for it to re-scan the new location, find the data and stop reporting an error.
You should also make sure to chown -R all the config/download files to the user the transmission-daemon process is running as if you change the user.


Is there a way to install and use smart scopes in 13.04 ?

You can install smart scopes from this ppa :

sudo add-apt-repository ppa:ubuntu-unity/experimental-certified
sudo apt-get update
sudo apt-get dist-upgrade
sudo apt-get install ubuntu-unity-experimental-certified
sudo apt-get upgrade

then restart.

To uninstall simply run

sudo apt-get install ppa-purge
sudo ppa-purge ppa:ubuntu-unity/experimental-certified

If the purge segfaults you can try

sudo sed -i 's/^deb/#deb/g' /etc/apt/sources.list.d/ubuntu-unity-experimental-certified-raring.list
sudo apt-get update
sudo apt-get remove ubuntu-unity-experimental-certified
sudo apt-get install gir1.2-dee-1.0/raring gir1.2-unity-5.0/raring libdee-1.0-4/raring libdee-dev/raring libunity-common/raring libunity-core-6.0-5/raring libunity-dev/raring libunity-protocol-private0/raring libunity9/raring unity/raring unity-common/raring unity-lens-applications/raring unity-lens-files/raring unity-lens-music/raring unity-lens-photos/raring unity-lens-video/raring unity-lens-friends/raring unity-scope-musicstores/raring unity-scope-video-remote/raring unity-services/raring unity-scope-gdocs/raring unity-scope-gdrive/raring

Full info here : http://www.webupd8.org/2013/04/how-to-install-unity-smart-scopes-in.html


An SSD is based on flash memory. Data written to it lasts forever; however, it has a limited number of writes.
Thus, daily or even weekly backups have a dramatic effect on drive life.

It is preferable to put backups on a separate drive. While backups on the same drive(separate partition) can help you recover from system failures, it can not be used in the event of a drive failure.


Synapse Application search bar indicator?

Use the following command on your terminal. Then It will be OK.

sudo add-apt-repository ppa:noobslab/apps
sudo apt-get update
sudo apt-get install indicator-synapse

Then follow the following instruction:

System Settings > Software & Updates > Other Software > find and click noobslab/apps repository > Edit > change Distrbution value to "trusty". Then sudo apt-get update and sudo apt-get install indicator-synapse. That's all.

Source: https://gist.github.com/brenopolanski/cb56125da4fede7a8abf


No, unless apt-get gave you an error message, everything is just fine. Error messages are generally starting with E: on the start of the line. The key press probably just messed up the printing of the progress.

Apt does sanity checks on downloaded packages, and corrupted packages will not be installed. You will get an error.

Furthermore, please paste text as text - don't include screenshots.


Cron running only the latest entry made into crontab

I found the problem. When writing to Crontab I was using the line break incorrectly and due to this at the end of the entry a ^M was recorded.


Trash icon incorrect after removing removeable media

When you delete files on an external storage media device, such as a USB drive, and then remove the drive without emptying the trash, the trash icon may show items still in the trash.

If you reformat that external drive, it will get a new UUID and, when you mount it again, it will appear to be a different drive.  So the OS will not know that it is the same drive and will not be able to clear the trash icon.

Rebooting the system with the USB drive removed will probably clear the trash icon.

I do not know where this tracking information is stored in Ubuntu.


cant install or boot from ubuntu 12.10 dvd

Hey friend :) u can check this out : My computer boots to a black screen, what options do I have to fix it? . And if it's help u please close this case and give me "up"  :D hahahaha


did you try apt-get -f install?

The Link "http://archive.linux.duke.edu/ubuntu/ wily-security/main" does not exist on my computer either.

However "http://archive.linux.duke.edu/ubuntu/dists/wily-security/main" exists.

Maybe you have to change the links in /etc/apt/sources.list or inside the directory /etc/apt/sources.list.d.


How to reduce software that is running during idle desktop state, and not needed otherwise?

To see current running processes enter ps u U <username> into the terminal.
It will bring up a list of running processes and their status. Note the process ID (PID)

To kill a particular process use the command kill -s signal pid where pid is the PID of the process you want to kill.

signal can either be a number or a name:

1 or SIGHUP - terminates interactive programs and causes daemons to reread their configuration files.
9 or SIGKILL - causes the process to exit without performing routine shutdown tasks
15 or SIGTERM - causes processes to exit but allows it to close or open files, etc

In your case you should use 15 or SIGTERM as the signal.

An example case kill -s 2496 SIGTERM


Kubuntu 14.04 keeps logging me out randomly

So I've googled and tried a lot but today I checked which updates had been downloaded in the last two days. There was a major OpenJDK update and since my WebStorm IDE relies on Java I decided to try installing the current version of Oracle JRE. As I had to do this myself (no installer provided), I used this (german) How-To: http://de.wikihow.com/Installation-von-Oracle-Java-unter-Ubuntu-Linux This worked like a charm and until now everything runs fine.

PS: In WebStorm installation docs I've found a little disclaimer that says that OpenJDK is not recommended and one should use Oracle Java if possible.


System boots with brightness level set to the lowest setting

This is a known bug. If you have a Launchpad account, mark it as affecting you to increase its heat, and thereby its likelihood of attracting developer interest.

In the meantime, a possible workaround might be to use a display manager other than LightDM, since the bug appears to have appeared at the same time as LightDM became the default.

To instead use GNOME Display Manager (which used to be the default), run sudo apt-get install gdm. After the installation completes, a warning about having multiple display managers installed will appear, followed by a dialog asking which you want to use:

Obviously, you should choose gdm.

To restore LightDM, run sudo dpkg-reconfigure gdm to trigger the above dialog to reappear. This time, choose lightdm instead.


waiting for network configuration network manager

I solved second problem in the way mentioned below.

In terminal:

gksudo gedit /etc/rc.local

Above the exit 0 line add:

/etc/init.d/network-manager start

Saved the new file and close gedit, reboot to test.


How to install latest version of Cheese from source in Raring?

Download the latest version for Raring from here

Installing..

Go to Downloads or directory where you downloaded .deb file

cd ~/Downloads

Install by executing:

sudo dpkg -i cheese_3.8.2-0ubuntu1~raring1_i386.deb

Be sure that you have installed the dependent packages of Cheese. If you run:

    $ sudo dpkg -i cheese_3.8.2-0ubuntu1~raring1_i386.deb

It will give errory message some what like:

Selecting previously unselected package cheese.
(Reading database ... 227378 files and directories currently installed.)
Unpacking cheese (from cheese_3.8.2-0ubuntu1~raring1_i386.deb) ...
dpkg: dependency problems prevent configuration of cheese:
 cheese depends on libcheese-gtk23 (>= 3.4.0); however:
  Package libcheese-gtk23 is not installed.
 cheese depends on libcheese7 (>= 3.5.1); however:
  Package libcheese7 is not installed.
 cheese depends on libclutter-1.0-0 (>= 1.13.0); however:
  Version of libclutter-1.0-0 on system is 1.10.6-1~precise1.
 cheese depends on libclutter-gtk-1.0-0 (>= 1.4.0); however:
  Version of libclutter-gtk-1.0-0 on system is 1.2.0-0ubuntu1.
 cheese depends on libglib2.0-0 (>= 2.35.9); however:
  Version of libglib2.0-0 on system is 2.32.3-0ubuntu1.
 cheese depends on libgnome-desktop-3-7 (>= 3.2.0); however:
  Package libgnome-desktop-3-7 is not installed.
 cheese depends on libgstreamer1.0-0 (>= 1.0.0); however:
  Package libgstreamer1.0-0 is not installed.
 cheese depends on libgtk-3-0 (>= 3.6); however:
  Version of libgtk-3-0 on system is 3.4.2-0ubuntu0.5.
 cheese depends on cheese-common (>= 3.4); however:
  Package cheese-common is not installed.
 cheese depends on gnome-video-effects; however:
  Package gnome-video-effects is not installed.
dpkg: error processing cheese (--install):
 dependency problems - leaving unconfigured
Processing triggers for man-db ...
Processing triggers for desktop-file-utils ...
Processing triggers for bamfdaemon ...
Rebuilding /usr/share/applications/bamf.index...
Processing triggers for gnome-menus ...
Errors were encountered while processing:
 cheese

And thus installs a broken package. So fix this broken package by executing:

    $ sudo apt-get -f install
    $ sudo apt-get update
    $ sudo apt-get upgrade

apt-get upgrade is necessary because it insures that you have latest library files.

Then how to install with dependent packages (here you are:)

Latest version of Cheese requires following packages:

cheese-common gir1.2-cheese-3.0 libcheese-dev libcheese-doc libcheese-gtk-dev
libcheese-gtk23 and libcheese7

Download it from here one by one and put in the same directory where cheese_3.8.2-0ubuntu1~raring1_i386.deb is saved.
Then go to directory cheese and execute this command (I am assuming that you placed all .deb file in a directory cheese somewhere in your system.):

$ sudo dpkg -i *.deb

Reply for further assistance.. Hope it will work now.


How can I do recursive unzip from terminal?

My suggestion is to create a custom command by adding the following function in your .bashrc:

# Recursive UNZIP
# - covers only the firs level of the recursion;
# - works only with one input file
unzipr () {
    # Get the users input
    TARGET_ZIP_FILE="${1}"

    # Get the list of sub archive zip files
    ZIP_LIST="$(unzip -l "$TARGET_ZIP_FILE" | awk 'NR > 1 && $NF ~ /zip/ { print $NF }')"

    # Output the list of sub archive zip files
    if [ ! -z "${ZIP_LIST}" ]; then
        echo 'List of Sub Archives:'
        for ZIP in $ZIP_LIST; do echo -e " - $ZIP"; done; echo
    else
        echo "Sub Archives Not Found."
    fi

    # Extract and unzip the files
    for ZIP in $ZIP_LIST; do
        # Ask the user for his/her preferences
        echo -n "Do you want to extract and unzip \"$ZIP\" [Y|n]: "
        read preference

        # Extract the file according to the users preferences
        if [ -z "${preference}" ] || [[ "${preference}" =~ ^(y|Y).* ]]; then
            unzip "$TARGET_ZIP_FILE" "$ZIP"
            unzip "$ZIP"
            rm "$ZIP"
            echo
        fi
    done
}

Add these lines to the bottom of ~/.bashrc, then do source ~/.bashrc and you will have a command called unzipr. Here is how it works:


The "answer" to your question is:

sudo ufw insert 1 allow from 192.168.0.0/24

This will put the rule first in your rule set.

The order of rules is critical in ufw/iptables as a packet will match the first rule, subsequent rules are (for the purposes of this discussion) ignored.

To see all your rules, in order,

sudo ufw status numbered

For additional information see

https://help.ubuntu.com/community/UFW

https://help.ubuntu.com/community/IptablesHowTo

http://bodhizazen.com/Tutorials/iptables

http://blog.bodhizazen.com/linux/firewall-ubuntu-gufw/

http://blog.bodhizazen.com/linux/firewall-ubuntu-desktops/


Configure "Link-Local Only" without NetworkManager?

You must use a different IP address for your second PC:

ifconfig eth0 169.254.7.44broadcast 169.254.255.255 netmask 255.255.0.0


"FATAL: Module vboxdrv not found in directory /lib/modules/4.10.0-20-generic"

Try do reinstall "virtualbox-dkms"

sudo apt install --reinstall virtualbox-dkms


I want to write weather data via a python script twice a day to a csv file

writing / formatting.

https://docs.python.org/2/library/csv.html
http://java.dzone.com/articles/python-101-reading-and-writing

Same as #1 really.  Once you have the data you insert it accordingly.  You define the columns, format, etc.
crontab as suggested above would be easiest.
crontab -e
@hourly  /path/to/script.py --arguments


How do I add a script to start up functions?

Ok, here is a simple trick that you will be interested:

You will be looking on a command called:

x-terminal-emulator -e /your/script/location

But the problem is that if your program doesn't halt it will not display and the terminal will close immediately after the script execution so you can always pause the program after you want.

#!/bin/bash
# init
function pause(){
   read -p "$*"
}

# Your main script
# call it
pause 'Press [Enter] key to continue...'
# rest of the script if any
# ...

And now you already know how to add it on startup application you can add following to command: x-terminal-emulator -e /your/script/location and then you are done.

Make sure you have chmod +x script.sh for your program.


Must restart pulseaudio to get headphone working

I solve this by removing pulseaudio and stick with alsa. Firefox seems to require pulseaudio to output sound, so I use Chrome instead.

For sound volume applet I use volumeicon and it seems working well.

UPDATE: I can use apulse to run Firefox.

UPDATE: I don't find this issue (yet?) in Debian 10, I guess it's the update in new kernel (4.19)


Making python 3.3 default python 3 interpreter instead of 3.2

You can custom your python3 alias. For this, you can modify your .bashrc file by appending "alias python3='python3.3'" at the end of it. This shell script can do it for you :

#!/bin/bash

cd ~

# Create the ~/.bashrc file if it does not exist
if [ ! -f ./.bashrc ]; then
    touch .bashrc
    chmod 755 .bashrc
    echo "#!/bin/bash" >> .bashrc
fi

# Append the customed alias
echo " " >> .bashrc
echo "alias python3='python3.3'" >> .bashrc
echo " " >> .bashrc

# Reload settings in the .bashrc script
source .bashrc


Touchpad doesnt work until restart. Lenovo ideapad Yoga

I had a similar problem a couple of days ago where my touchpad wasn't working as it should after I suspended Ubuntu.

Try running these commands in terminal:

(If your mouse isn't working just press ctrl+alt+T to open terminal)

First:

sudo modprobe -r psmouse

Second:

sudo modprobe psmouse

If that fixes it, you can write a script that starts whenever you "resume" the computer from being suspended. I write a how-to in this thread

If the above isn't working:

Since you are using a Lenovo laptop (like I am) there might be a chance that installing Synaptics would fix it (I just prefer libinput)

There is a great tutorial on how to do it here

Basically you need to run the following in Terminal:

xinput list

And check under "Virtual Core Pointer" and see if there is an input with "Synaptics" in it's name.

If there is run:

apt list --installed

And search for xserver-xorg-input-synaptics

If it's not installed, install it by running:

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

Then reboot and hopefully that will fix your problems!


How to keep the audio profile at A2DP while using a mic with Bluetooth headset? (Push-to-talk)

Ondra, there is a very long pulse audio merge request discussion that contains most of the information.
tl;dr; to get things working pulse audio, bluez and kernel need to be updated (not trivially). As well a separate daemon hsphfpd is necessary.
Kernel updates are not progressing and user input to maintainers would be helpful in pushing things forward. Think about providing such. See here.
Without the kernel patches, using headphones' mic leads to terrible audio quality (HSP/HFP mode of operation).
But there is chance that only Pulse patches (and support from your headphones) can enable A2DP bi-directional audio which should be alright for most purposes.
And that patch is progressing well at the moment. More feedback on it shouldn't hurt.
Update: THings in above mentioned pull request escalated very quickly and seems like PulseAudio may never implement proper bluetooth support. Lets hope for Pipewire which already has some patches.


Format the partition with Windows (GNOME Disks or GPartEd can do that for you), then sudo update-grub so Grub knows Windows isn't there anymore.


Screen refresh problems following 12.04 upgrade

I had this problem - I resolved it by changing my desktop background from a solid color to a gradient (any image wallpaper worked too.)


Problem to enter in NTFS partition "The disk contains an unclean file system"

You could try this (worked for me with similar problem):

sudo apt-get install ntfsprogs
sudo ntfsfix /dev/sdb2

That worked for me. Good luck!


Try to run wine uninstaller like Windows "Add/Remove Programs" function with this command:

wine uninstaller


How to change the color themes in gnome 3?

You have to directly edit the theme. The themes are located under /usr/share/themes. For the Adwaita theme, the colors are declared in the gtk.css file.


Pymol starts to work fine without python crash after i revert the nvidia driver back to an older version 304.131.
Installed through Ubuntu repository:

sudo apt-get install nvidia-current

You can also specific a version to install, e.g.
sudo apt-get install nvidia-331
sudo apt-get install nvidia-340

Hope these helps.


Why not use Ubuntu One for it? Its already integrated in OS.


How do I install my Wacom Intuos 2 serial tablet?

Serial tablepc based wacom tablets should just work without any additional attention. If they don't then we will need to do a bit of investigation from the command line (Applications > Accessories > Terminal).

First check to see if the serial port is registering correctly:

ls /dev/ttyS*

For each one of those you can run this command to check it's pnp information (remember to change the ttyS0 to each of the ttyS nodes found above):

udevadm info -a -p $(udevadm info -q path -n /dev/ttyS0)

It's probably good if you copy and paste all the information here so we can see what's happening. Normally the output for a wacom should look like this:

looking at device '/devices/pnp0/00:0a/tty/ttyS0':
    KERNEL=="ttyS0"
    SUBSYSTEM=="tty"
    DRIVER==""

  looking at parent device '/devices/pnp0/00:0a':
    KERNELS=="00:0a"
    SUBSYSTEMS=="pnp"
    DRIVERS=="serial"
    ATTRS{id}=="WACf004"

  looking at parent device '/devices/pnp0':
    KERNELS=="pnp0"
    SUBSYSTEMS==""
    DRIVERS=""

If you don't see any wacom info here then your device probably isn't a tabletpc wacom device and is probably plugged into a serial port on your computer. These devices are no longer supported in Ubuntu and you should downgrade to Karmic until support is added back in for newer xservers (1.7 and 1.9).


Root is the user root's home folder. Normal users should not have permissions on this directory - and there is nothing inside this folder of interest.

Ubuntu does not use the root user, but the directory is required to comply with file systems standards.

Furthermore, Linux uses filesystem access control. A normal user does not have access to everything.

You may have a look at this Q&A for information on how to become the super user of the system if you need it. In general, be careful with files that require root access for editing or viewing. Changing them may break your system.


Grub Dual boot Windows 10 Ubuntu 14.04 LTS trouble to load Windows from Grub

I completely spaced out and forgot about this bug, which is almost certainly the cause of your problem:

https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1091464

There are a number of workarounds noted in the bug report, but the two simplest are:

Disable Secure Boot in your firmware. Details of how to do this vary from one system to another. I wrote a Web page that shows a few examples; see here if you need help.
Install my rEFInd boot manager. It will take over as your primary boot program, and it lacks this problem, so you should be able to boot either OS with Secure Boot enabled. You can install it from the Debian package or using the PPA.


Any interface for building a server in Linux Xubuntu. (not desktop)

What do you mean by interface? For most people the command line (over SSH if remote access is required) is plenty.

Xubuntu is made up of all the same packages as Ubuntu (as is Ubuntu Server). Anything you can do in one of them (eg sudo apt-get install lamp-server^) will work in the other.


Why am I having so many problems installing Ubuntu 13.10 alongside Vista?

The "unable to satisfy partition parameters" message usually indicates a mismatch in the partition alignment policy between the current partitioning program (Ubuntu's installer in this case) and whatever created existing partitions on the disk. To elaborate, in the past partition start and end points were aligned on "cylinder" boundaries. Disk cylinders are real, but the "cylinder" boundaries used for partitioning have been convenient fictions since the 1990s. More recently they've become INconvenient fictions, and now they're downright detrimental, which is why new software aligns partitions on 1MiB boundaries.

The problem is that there seems to be a rounding problem in libparted, such that when you tell it to create a new partition with no space between the preceding or following partition, it tends to try to adjust the alignment, which can create an overlap in the partitions. The solution is to create your partitions manually, but leave a short (1MiB should be enough) gap between the partitions you create and any that already exist. Unfortunately, this means you'll need to use the "Something Else" installation option rather than auto-partitioning.

That said, your other errors sound like they may be symptoms of hardware problems. Certainly problems that can't be repeated are often symptoms of hardware failures. Posting the complete and exact error messages is necessary for further diagnosis, though. If necessary, take a photo with a digital camera and post it (or a link to it) here. Be sure the text is legible, though.


Will I be able to turn my ubuntu touch phone into a desktop pc?

Today's article on BBC says No, not yet:

http://www.bbc.com/news/technology-31148661


Overwrite existing Ubuntu install with Server Installer

I will assume when you mention the Installer, you mean the LiveCD or LiveUSB where you have the Ubuntu installer.

First, if the installer is not giving you the option for F6 it could either be that it booted too fast or that it is damaged (The CD or the Image somehow got damaged).

Secondly, since you do not care about the files or the need to do a backup then I can simply say to boot the computer from within a working LiveCD or LiveUSB, and tell the Ubuntu installer, where it asks what option do you want to choose (Between leaving the current OS intact, removing all partitions and installing it from scratch or doing it manually), to just remove everything.

Already tried right now. My scenario was a system with Ubuntu 12.04 32 Bit. I then proceeded to execute a LiveCD of Ubuntu Server 12.10 Server 64 Bit. It ran, when asked what to do with the other OS I simply selected, remove it and install 12.10 Server alone.

After that I had myself an Ubuntu Server 64 Bit system.

Now, in regards to the 3rd party tools. If this means LiveCD, LiveUSB, Network install and other common methods then we have a problem since, without this, there is no way to install Ubuntu.

Am also assuming this is not a WUBI installation. This would cause additional problems with what I just wrote.


I am not confused at all. It is a User Interface = UI. See this question:

Previously asked question - what is unity

and this link extracted from answer to the earlier question:

early Launchpad blueprint for Unity

Regards.


Your problem will be answered, for the most part, by downloading Ubuntu and use the "try Ubuntu".
As you can tell from these 2 links there are mixed results ...

Installing Ubuntu 13.04 on Dell XPS 12 9Q23 in multi booth mode stops at black scren
http://forum.notebookreview.com/dell-xps-studio-xps/693432-xps-12-owners-lounge-39.html#post8975843

From the 2nd link:

  It is definitely not perfect overall, but Ubuntu 12.10 works very well for me. I got over 4 hours use last night, on wireless, two-thirds brightness, streaming music continuously, browsing the web, occasional flash video clip; and it said I still had over 120 minutes of battery left.

  Things I find do work perfectly:

  display port (I use a mini display port -> hdmi cable to monitors and tvs and it just works)
  wifi
  bluetooth
  usb
  display
  audio
  keyboard shortcuts under F keys (except for the monitor switch under F1 doesn't seem to do anything)
  install via usb; use the usb creator tools to turn the ubuntu cd iso into usb boot images; you can even use it for a while this way since it will write your changes/data back to the usb and not mess with the ssd until you say "install"
  the virtual keyboard "onboard"; for desktop use, and for logging back in after the screenlock activates

  Things to tweak:

  go into bios and disable the security and enable booting legacy devices so you can boot off usb
  touchpad is currently just the basic one; no multitouch, etc; but this works fine for me; I'm sure there will be a driver update "soon"
  change the suspend mode to pm-suspend-hybrid; it seems to work perfectly then when you close the lid, choose sleep, battery runs low, etc
  as you noticed, there is a bug in the touchscreen driver that it doesn't send TOUCH_END events (at least I think that is the problem) so some programs in unity, like nautilus, don't work completely until they update the driver, or nautilus, or you disable the touchscreen; I almost didn't notice it since I don't use nautilus much
  you have to invert the brightness settings with a boot option or the internal display backlight is off at boot; luckily I had the external monitor connected when I installed; I think it is "i915.invert_brightness=1" acpi_osi=linux acpi_backlight=vendor" in /etc/default/grub
  tie a shortcut to the side button so you can use it to rotate the display (optional)

  Hopefully 13.04 will have all these fixes; and maybe 12.10 updates.

But it should all be fixable (in some sort of way). If there are problems asking the right question and giving the correct information here will get those issues diagnosed and/or fixed.


Will my WLAN interface IP address ever change?

IP is never assigned to the card for its lifetime it can be specified statically in the network config or it can be assigned by DHCP server.
To answer your question - yes, it can be changed. And the other question - will it ever change - it could but does not have to. You can get the same IP from DHCP server every time (but does not have to as DHCP can be set to provide the same IP every time)
Maybe if you provide more context why you ask this you could get more specific answer.


Can i run the latest version of Ubuntu on this computer?

Ubuntu 20.04 is a bit unstable. Try to use ubuntu 18.04. If your computer is so weak you can try to run Lubuntu or Kubutu. They are more speed than Ubuntu gnome.
Anyway, give us the output of dmesg -l err in ubuntu 20.04.


Why does "apt list --all-versions" show more packages than "dpkg -l"?

dpkg can only provide information about what it knows, which is limited to packages and versions that had some dpkg operation applied to them.

apt, on the other hand, has far more information - it includes everything in the package lists it gets from repositories. Obviously it's unlikely that dpkg operations have been done for most available packages and versions, and so of course the output of dpkg-query does not include those and is, hence, limited.


How to make bash stop tab autocompleting hidden directories

Just add this line to your ~/.bashrc (if you don't have one, create it):

bind 'set match-hidden-files off'

And bash-completion should behave the way you want.

There are also many other options you might want to tweak in bash-completion. To see a complete list, read the manual ;)


Followed this guide from @Vijay's comment.


Boot: error: attempt to read or write outside of disk 'hd0' after update

The solution that worked for me was re-installing grub using a live USB/CD Ubuntu installer.

After booting to the installer, select try Ubuntu and follow the instructions here to reinstall/reconfigure grub on your main Ubuntu installation.

  Mount the partition your Ubuntu Installation is on. If you are not
  sure which it is, launch GParted (included in the Live CD) and find
  out. It is usually a EXT4 Partition. Replace the XY with the drive
  letter, and partition number, for example: sudo mount /dev/sda1 mnt.

sudo mount /dev/sdXY /mnt

  Now bind the directories that grub needs access to to detect other
  operating systems, like so.

sudo mount --bind /dev /mnt/dev &&
sudo mount --bind /dev/pts /mnt/dev/pts &&
sudo mount --bind /proc /mnt/proc &&
sudo mount --bind /sys /mnt/sys

  Now we jump into that using chroot.

sudo chroot /mnt

  Now install, check, and update grub.

  This time you only need to add the drive letter (usually a) to replace
  X, for example: grub-install /dev/sda, grub-install –recheck /dev/sda.

grub-install /dev/sdX
grub-install --recheck /dev/sdX
update-grub

  Now grub is back, all that is left is to exit the chrooted system and
  unmount everything.

exit &&
sudo umount /mnt/sys &&
sudo umount /mnt/proc &&
sudo umount /mnt/dev/pts &&
sudo umount /mnt/dev &&
sudo umount /mnt

  Shutdown and turn your computer back on, and you will be met with the
  default Grub2 screen.

It seems for some reason (maybe some update) grub in the MBR is referring to a wrong location under hd0. Reinstalling/reconfig grub fixed it for me.


Problems compiling Wireshark from Source (SVN) during .calling /configure

Ok. The solution is (of course :-/ ) quite easy:

make distclean
./configure
make

... ready (or using cmake, what I didn't recognized)


Edited my `.bashrc`, now I can't use my desktop

If truly all you did was change .bashrc, you can log in via a terminal and fix it.  Here is an unaltered .bashrc from 14.04 for you to use.

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# don't put duplicate lines or lines starting with space in the history.
# See bash(1) for more options
HISTCONTROL=ignoreboth

# append to the history file, don't overwrite it
shopt -s histappend

# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
HISTSIZE=1000
HISTFILESIZE=2000

# check the window size after each command and, if necessary,
# update the values of LINES and COLUMNS.
shopt -s checkwinsize

# If set, the pattern "**" used in a pathname expansion context will
# match all files and zero or more directories and subdirectories.
#shopt -s globstar

# make less more friendly for non-text input files, see lesspipe(1)
[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"

# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
    # We have color support; assume it's compliant with Ecma-48
    # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
    # a case would tend to support setf rather than setaf.)
    color_prompt=yes
    else
    color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
    alias ls='ls --color=auto'
    #alias dir='dir --color=auto'
    #alias vdir='vdir --color=auto'

    alias grep='grep --color=auto'
    alias fgrep='fgrep --color=auto'
    alias egrep='egrep --color=auto'
fi

# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

# Alias definitions.
# You may want to put all your additions into a separate file like
# ~/.bash_aliases, instead of adding them here directly.
# See /usr/share/doc/bash-doc/examples in the bash-doc package.

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

# enable programmable completion features (you don't need to enable
# this, if it's already enabled in /etc/bash.bashrc and /etc/profile
# sources /etc/bash.bashrc).
if ! shopt -oq posix; then
  if [ -f /usr/share/bash-completion/bash_completion ]; then
    . /usr/share/bash-completion/bash_completion
  elif [ -f /etc/bash_completion ]; then
    . /etc/bash_completion
  fi
fi


Can we use Microsoft Excel keywords in ubuntu's office as we are now using in Windows XP?

Install libreoffice on your Windows machines first and try it out. If it works to your satisfaction there, you can move on to Ubuntu without worries.

MS Office on Ubuntu is possible, but tricky and youmay run in to real difficulties down the line. I wouldn't recommend it.


I recommend you to but in Wubi disk/dvd and with Gparted create an extended partition. Attention! You could lose data!


Simple TeXmaker keyboard shortcuts messed up after upgrade (14.04-14.10)

I have the same issue. I installed the 4.4.1 deb package for ubuntu 14.10 from the Texmaker website which resolved the issue for me (http://www.xm1math.net/texmaker/download.html#linux)


Can't to run games .ISO on PCSX(Ubuntu 12.04)

Be sure the iso is not corrupted.
I use the same emulator (V 1.9.92) with these settings:

/Graphics - XVideo Driver 1.1.17

/Sound - SDL Sound 1.6.0

/Controller 1 and 2 - Gamepad/Keyboard Input 1.1.0

/CD-ROM - CD-ROM Drive Reader 1.0.0

/BIOS- Simulate PSX BIOS

mayority are default configs and work fine for me.


Where is the alternate installation ISO for Ubuntu Saucy?

As part of ongoing efforts to reduce the number of images we ship for Ubuntu, and to make the desktop image more useful in a variety of scenarios, Dmitrijs Ledkovs has been hard at work in quantal adding support for LVM, cryptsetup, and RAID to ubiquity.
[...]
It [dropping the alternate CDs] lets us tighten our focus on making the desktop CD shine: fewer images to QA, fewer different paths to get right (like the CD apt upgrader case) means more time to focus on the things that matter.

More on the mailing list.
That proposal got accepted so there is no alternate anymore. You need to use the normal installer.

SIS on board graphics.

You need better hardware. SIS has not a lot of Linux affinity.


Does reinstalling openssh-server change the host key?

Your original host keys would be deleted if you had purged openssh-server, using either apt-get purge openssh-server or apt-get remove --purge openssh-server. In this case the keys would be regenerated, and would naturally be different. If openssh-server was just removed, the key files should not have been touched on reinstallation.

The host keys do indeed only depend upon the files in /etc/ssh/, unless ssh is configured to look elsewhere. This would be evident by any unusual looking HostKey lines in /etc/ssh/sshd_config. The default HostKey lines are:

# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
HostKey /etc/ssh/ssh_host_ed25519_key

It is definitely worth checking the file to see whether you're using host keys from a non-standard location, as your key files appear not to have been modified.

If the keys on the server are as expected, the warning is most likely being generated at the client end of things. As Germar said, the problem could be caused by reuse of a dynamically assigned IP address which had previously been used by another server.


GPG and SSH encryption of file need help

Although both use encryption, and although they might sound the same, they are otherwise unrelated.

GPG

When you encrypt with gpg, a set of keys is made in ~/.gpg to be used to encrypt and decrypt files / emails.

There is a public key you distribute to others, so they can verify your signatures and encrypt files for you, and a private key you keep, used for decrypting files sent to you.

See : http://www.madboa.com/geek/gpg-quickstart/

SSH

SSH keys are used to log into ssh servers (rather then passwords). Again there is a public key (you put on the server) and a private key (you keep).

See :

https://help.ubuntu.com/community/SSH/OpenSSH/Keys

http://bodhizazen.com/Tutorials/SSH_keys


Stop Alt from opening/searching menus on Kubuntu

This is the Common User Access menu IBM developed decades ago, which dates back before MS-DOS, and is a standard on many, many operating systems.

Switch Alt and Meta keys in Keyboard settings, then Change  all Alt+... keyboard shortcuts to Meta+... ones and vice versa; rather tedious, but works. Thanks to lashkevi for the tip.


How to use TRIM on encrypted home folder

Encrypted home folder are virtualy mounted unencrypted.

All your files in your encrypted /home/username
folder exist real in:/home/.ecryptfs/username
in encrypted format.

So if you use "fstrim -av" you are trimming the complete disk unneeded.

~$ fstrim -av
/home/username: 271.1 GiB (291104260096 bytes) trimmed
/: 0 B (0 bytes) trimmed

After every reboot it will do the same.

So it is better to trimm only the real files written on disk:

fstrim -v /

Add a weekly scheduler:

sudo cp /usr/share/doc/util-linux/examples/fstrim.{service,timer} /etc/systemd/system
sudo systemctl enable fstrim.timer

and edit /etc/systemd/system/fstrim.service

[Unit]
Description=Discard unused blocks

[Service]
Type=oneshot
ExecStart=/sbin/fstrim -v /


Regularly visited website is now partially disabled in Firefox, but works on other devices and browsers

Try installing Chromium from a shell prompt

apt-get install chromium-browser

when it launches after install completes, import the bookmarks from Firefox

If Chromium works well for your website, start Firefox and save your bookmarks with {Ctrl-Shift-B} to Show All Bookmarks then
Import and Backup
Export Bookmarks to HTML
and specify a path and filename to save your bookmarks to.

Then, reset Firefox. (Many thanks to heynnema for reminding me of this.)

  Click the menu icon; it looks like three stacked lines and is at the top right of the browser window.
  Go to the end of the drop-down menu, and click on the question-mark icon.
  Pick 'Troubleshooting information' in the slide-out menu.
  Click on the 'Reset Firefox' button at the top right of the new Web page.
  In the confirmation pop-up window, choose 'Reset Firefox'.
  Import your bookmarks from {Ctrl-Shift-B}

Retry and see if the desired website is consistently accessible now.

Should that fail, uninstall Firefox from a shell prompt with

sudo apt-get purge firefox

reinstall it, import your bookmarks from {Ctrl-Shift-B} and your problem will be solved.


Firefox keeps changing http://localnode:8080 to http://localnode.com8080/. How do I change this?

You need to define localnode as 127.0.0.1 in your DNS or in your hosts file (/etc/hosts).
Your browser is trying localnode.com because it can't find localnode. Or use http://localhost:8080


awk - compare files and print lines from both files

How about

$ awk 'NR==FNR {a[$1]=$2; next} $2 in a {print $0, a[$2]}' OFS='\t' file_2.txt file_1.txt
apple  tree   5   3
great  see    10  7.43
see    apple  3   5.21
tree   bee    11  1


Can I install a multiverse package, then disable non-free sources, and still let it upgrade?

An installed package won't continue to automatically get upgrades if you disable the software source that the package was installed from (for example by commenting out the software source's line in your software sources by preceding it with a # character), however you can still manually upgrade that package by re-enabling its software source and reinstalling the package, and then disabling its software source again.
When you reinstall a package with sudo apt reinstall package-name, apt will try to locate that package in your software sources and install the latest available version of that package. When a package is upgraded by sudo apt upgrade it also upgrades it to the latest available version of that package.
Dependencies cross repositories only if you are also adding suggested packages with the --install-suggests option when running a sudo apt install command. Ubuntu installs only the package itself and its recommended packages by default. You will get an error message if you try to install a suggested package that is not available from your system's software sources.
Even if a package has been installed by apt there are commands that tell apt to treat that package like a manually installed package, so that it cannot be either automatically removed or automatically upgraded without toggling an option first. sudo apt-mark manual package-name is used to mark a package as being manually installed, which will prevent the package from being automatically removed if no other packages depend on it. sudo apt mark hold package-name hold is used to mark a package as held back, which will prevent the package from being automatically installed, upgraded or removed. unhold is used to cancel a previously set hold on a package to allow all actions again. apt reinstall --simulate package-name simulates the re-installation of a package the results of which will show whether reinstalling that package will also install any new packages or dependencies which may include non-free packages that aren't currently installed. Use sudo apt-mark hold to prevent these unwanted new packages from being installed.


Wifi not working on fresh ubuntu installation on new computer

Internet connection maybe something different from wifi connection . If you can connect to your wireless access point it means you don't have any trouble with you NIC .

For troubleshoot this problem you may provide more detail about your Routing table and DNS configuration .

For getting know about these detail , try :

 $ ip a

which show your run time networking status . Check If your connection has IP and CIDR ( /x ) is as same as your network ( Some issue for some routers ) .

 $ ip route show

This will show you routing tables . Check default parameter is set correctly and also is same as UG flag in following command route -n .

After these you can try to checking your DNS configuration . Check /etc/resolv.conf if Network manager wrote right nameserver . Also check /etc/hosts to check if there is any mistyping . Also check /etc/nsswitch for getting know about which DNS configuration read first .

In any steps if you want to do any changes do not edit it by hands . Network manager has great utility for managing them nmcli .

Try to make new profile :

 $ nmcli connection add type ethernet ifname wlp18s0 con-name ali save yes

Then modify your connection :

$ nmcli connection modify ali ipv4.address 1.2.3.4/24

And you can find out more options to edit profile when you enter ipv4. press TAB .


every month ssh stuck (and not only ssh)

What I would start with is :

before rebooting, if you still have access to the server (physical console, com port, etc.) : check the service status (service sshd status) and see if some process is still listening to your ssh port (netstat -anp)
check auth.log for any unusal ssh activity just before the service crashed
if the problem occurs on the same date every month, you could check the cron tables for anything planned at that time.

Please, note that I'm not an experienced sysadmin, only a somewhat experienced user.


Can use Unetbootin to install other Linux Distributions from within Ubuntu (like Fedora or Mint)?

In one of my laptop partitions I've got a variant of Ubuntu Lucid (called Deepin) installed.  I used Unetbootin to install Ubuntu based distros inside that partition a few times (I mean, one distro at a time).  Each time Unetbootin basically added one or two directories containing the live data of the distro and added boot entries to the Grub menu.  On rebooting after installing the distro this way,  I select the entry "Unetbootin" on the Grub menu will run the distro the same way as running the live CD or USB of the distro, but much faster.

In case I want to delete the installed distro, I just run Unetbootin again within my Lucid variant (Deepin) and I'll be asked if I want to remove the installed distro.  On confirming, the distro will be removed (the added directories and Grub additions) right away.

I have tested a few distros this way and I'm very happy with it.  But I must make it clear that I haven't tested non-Ubuntu-based distros this way; and I recall reading somewhere that some versions of Unetbootin may not work this way.


I think you are suffering the bug #1021375

You can workaround it by renaming the folder ~/.config/nautilus and then logout and log back in.

mv ~/.config/nautilus ~/.config/nautilus-bak
Logout.
Login.


I reported a bug on launchpad a while ago and it seems to be fixed now, what should I do?

If you can't test it on Ubuntu 14.04, just leave it as it is.

Somebody will probably test it and report.


partition detected as /dev/sdb without identifier

It's not normal, but it's not unusual either. It's entirely possible to format the disk itself (like you suggested, mkfs .... /dev/sdb) instead of creating a partition table and partitions and then formatting a partition. See discussion on the merits of a partitionless filesystem over on Unix & Linux.


I want to install Ubuntu leaving Windows 8 and recovery partitions untouched

First of all if you only have once drive then you will have to partition it.

The other option is using "wubi", this will install Ubuntu like a program that can be uninstalled in the "programs" in control panel.
https://wiki.ubuntu.com/WubiGuide

The other option is to create a bootable Ubuntu USB drive, in this no changes are made to the system and all settings are saved to the USB drive.


Full disk encryption - separate home partition

Warning:  Keep in mind what you are doing has to be done right or you may potentially destroy other systems on your hard drive or data on other partitions.  If you are installing to the entire hard drive and want to overwrite the entire disk, no worries.

When you are installing, when you see this screen:

Choose Something else.

You will need to create the minimum of two partitions (three if you want a swap).

Create one partition for you system and set it's mount point to '/'

Create another partition for your home directory and set it's mount point to '/home'

Create a swap partition as well if you need one.

When you are asked to encrypt the /home directory, choose that option.

See this tutorial before you start this process.  If you have another system installed already and want it to install beside it, make sure you back it up with remastersys or just back up your files.


How to share internet by creating virtual access point in Ubuntu

If you are running network-manager, just click the notification-icon (networking icon), click create new wireless network, and then enter a name and optionally a password.

Please comment if this is not what you mean.


How to format/align conky's configuration file?

I don't think it's possible to align or arrange the text in your config file without influencing the conky itself, but maybe setting a Highlight Mode in the text editor you use can help to get better oversight of the text. I use 'Scientific matlab' in gedit, you get different colors for different kinds of items...


How to create a new folder from a terminal with administrative permissions?

Create the folder from a command line terminal using:

sudo mkdir /usr/java

You need sudo to make changes to /usr because /usr is owned by the root user.


How to List all available apps on my machine

Open the Software Center and click the "Installed" button in the toolbar to see a list of applications that you currently have installed:

The Software Center is the icon in the Unity launcher that looks like this:


How to recover free space after installing ubuntu 12.04

You don't have to reinstall Ubuntu. Simply use gparted to allocate the free space.

sudo apt-get install gparted

Fire it up with

gksudo gparted

and reallocate the free space as desired.


Can I modify unity keyboard shortcut overlay?

All the shortcuts that show in the keyboard shortcut overlay are hardcoded. If you want to change or modify what shows up, you need to compile Unity from source.

How do I build Unity from source?

In the Unity source, go to Plugins → UnityShell → src → unityshell.cpp and modify them as you wish and then build Unity from source.

My keyboard shortcut overlay modification to include the shortcut for Video lens:


You could use the output of
   dpkg -s <packagename>   or  dpkg-query -l <packagename>

in your script for the purpose.
Courtesy:https://stackoverflow.com/questions/1298066/check-if-a-package-is-installed-and-then-install-it-if-its-not

e.g.

#!/bin/sh

for P; do
    dpkg -s "$P" >/dev/null 2>&1 && {
        echo "$P is installed."
    } || {
        echo "$P is not installed."
    }
done

Usage: script.sh package1 package2 .... packageN

Courtesy:https://stackoverflow.com/a/10594734/749232


Re-Sending an email from the command line

According to RFC 5322 Internet Message Format the body of the message starts after an empty line.

You can use awk to print everything in mail.txt after the first empty line, like this:

awk '/^$/,0' mail.txt

So you could do something like

awk '/^$/,0' mail.txt | mail -s "Test" me@nowhere.net

That, however, will start the output with an empty line. If you want to avoid that, use a slightly more complicated awk range:

awk 'p; !/./{p=0}/^$/{p=1}' mail.txt | mail -s "Test" me@nowhere.net

This last trick is one I picked up here.


You cant install Ubuntu from windows. You have to boot from the DVD.
In Bios change boot-order, so that DVD is before Harddisk.


Ok, I figured this out... Because the graphite-processes are, actually, launched by Apache in a typical Ubuntu config, it is the Apache, that needs to be notified, whenever the logs are rotated.

So I copied the postrotate clause from /etc/logrotate.d/apache2 into graphite-provided file.

Alternatively, one could simply remove the graphite's file and add the /var/log/graphite/*.log into the list of apache-logs...

Overall, I have to admit, I'm disappointed about the Graphite packages available for Ubuntu -- they are way out of date and subtly misconfigured out of the box...


What does this /dead.letter file talking about a SMART warning mean?

I just saw one today, so curious to know what in that dead.letter (Is it from a hacker? :D). Similar contents:

Date: Thu, 08 Dec 2016 00:48:26 +0100
To: root
Subject: SMART error (FailedOpenDevice) detected on host:
 user.dz-blueskies
User-Agent: s-nail v14.8.6

This message was generated by the smartd daemon running on:

   host name:  user.dz-blueskies
   DNS domain: [Empty]

The following warning/error was logged by the smartd daemon:

Device: /dev/sdb [SAT], unable to open device

Device info:
WDC WD20NMVW-11W68S0, S/N:WD-WX51A82P0486, WWN:5-0014ee-25cb067e3, FW:01.01A01,
2.00 TB

For details see host's SYSLOG.

You can also use the smartctl utility for further investigation.
Another message will be sent in 24 hours if the problem persists.

User-Agent: s-nail is the mail tool so checked man s-nail | grep -n dead and found as Rinzwind said.

2334:     DEAD    The name of the file to use for saving aborted messages if save is set; this defaults to dead.letter in the user's HOME directory.
2507:               DEAD=+dead.mbox

smartd is configured to send email to the root user, from /etc/smartd.conf:

DEVICESCAN -d removable -n standby -m root -M exec /usr/share/smartmontools/smartd-runner

The error is about smartd that could find accessible device node /dev/sdb (in my case, external USB drive). Possibly, after unclean eject, I couldn't test because I have to wait 30min for next smartd scan.

$ grep smartd  /var/log/syslog
Dec  8 00:48:26 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 117 to 109
Dec  8 00:48:26 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 00:48:26 user.dz-blueskies smartd[1086]: Sending warning via /usr/share/smartmontools/smartd-runner to root ...
Dec  8 00:48:26 user.dz-blueskies smartd[1086]: Warning via /usr/share/smartmontools/smartd-runner to root produced unexpected output (118 bytes) to STDOUT/STDERR:
Dec  8 00:48:26 user.dz-blueskies smartd[1086]: /etc/smartmontools/run.d/10mail:
Dec  8 00:48:26 user.dz-blueskies smartd[1086]: Cannot start "/usr/sbin/sendmail": executable not found (adjust *sendmail* variable)
Dec  8 00:48:26 user.dz-blueskies smartd[1086]: Warning via /usr/share/smartmontools/smartd-runner to root: successful
Dec  8 01:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 109 to 107
Dec  8 01:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 01:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 107 to 106
Dec  8 01:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 02:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 02:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 03:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 03:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 04:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 106 to 107
Dec  8 04:18:26 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 04:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 107 to 106
Dec  8 04:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 05:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 05:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 06:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 106 to 108
Dec  8 06:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 06:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 108 to 109
Dec  8 06:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 07:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 07:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 08:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 08:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 09:18:26 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 09:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 109 to 110
Dec  8 09:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 10:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 110 to 108
Dec  8 10:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 10:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 108 to 109
Dec  8 10:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 11:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 11:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 109 to 108
Dec  8 11:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 12:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 108 to 109
Dec  8 12:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 12:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 109 to 108
Dec  8 12:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 13:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sda [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 108 to 109
Dec  8 13:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 13:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 14:18:26 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open() failed: No such device
Dec  8 14:48:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], open device worked again, warning condition reset after 1 email
Dec  8 14:48:26 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 120 to 128
Dec  8 15:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], SMART Prefailure Attribute: 3 Spin_Up_Time changed from 211 to 210
Dec  8 15:18:25 user.dz-blueskies smartd[1086]: Device: /dev/sdb [SAT], SMART Usage Attribute: 194 Temperature_Celsius changed from 128 to 121

BTW, Those temperature measurements don't seem right (Celsius), more real as Fahrenheit.
I could get same syslog message even with safe eject, smartd scans the devices at start then keep monitoring them even after eject.

Your message is old 23 Sep 2016, all most 3 months, no logs left and issue didn't repeat, no mail pending too. I think we need a way to reproduce it, may by decreasing smartd interval, edit its systemd service file.

$ sudo vim /lib/systemd/system/smartd.service
ExecStart=/usr/sbin/smartd -n -i 10 $smartd_opts

-i 10 for 10 sec interval. However, be aware smartd is using it as strict value for data query, and not for reporting (I could notice some intervals 11sec to 5min between messages).

Restart the service:

sudo systemctl daemon-reload
sudo systemctl restart smartd

To follow it in a terminal using:

tail -f /var/log/syslog | grep smartd


Open a terminal emulator (Ctrl + Alt + T) and allow the Multiverse repository with the command:

sudo add-apt-repository "deb http://archive.ubuntu.com/ubuntu $(lsb_release -sc) multiverse"
sudo apt-get update

And then you'll have to install ubuntu-restricted-addons and ubuntu-restricted-extras.

For Ubuntu use the command:

sudo apt-get ubuntu-restricted-addons
sudo apt-get ubuntu-restricted-extras

For Kubuntu use:

sudo apt-get kubuntu-restricted-addons
sudo apt-get kubuntu-restricted-extras

For Lubuntu use:

sudo apt-get lubuntu-restricted-addons
sudo apt-get lubuntu-restricted-extras

For Xubuntu use:

sudo apt-get xubuntu-restricted-addons
sudo apt-get xubuntu-restricted-extras


Cannot open output file: Permission denied

Yes, you have to change the permissions of the directory as well.

This is because if you only have write permissions to the files inside the directory, you can't just create a new file because you don't have write permissions for that file (it doesn't exist, so no permissions to create it).

If you have write permissions for the directory you can create a file inside it because you have write permissions for the directory itself.

To make yourself the owner (terminal way):

Check your user name:

whoami

Make yourself the owner of the directory and its contents:

sudo chown -R "$USER:" /path/to/the/directory

The -R flag stands for recursive, so that directory and all its subfiles and subdirectories will change owner. Remove the -R flag to just change the permissions of the directory itself.

Now you should be able to create files or directories because you're now the owner of the directory and all its content. If you still can't, give the owner write permissions to the directory and its content using the following command:

chmod -R 700 /path/to/the/directory


Ok so ubuntu only uses 8gb +/- hard drive space that's way better then windows 20gb just to install.

steam is coming to linux very soon you can still use steam using wine and play on linux only thing most gams do not work yet.

Valve: “Windows 8 a Catastrophe for Everyone”
http://www.omgubuntu.co.uk/2012/07/valve-windows-8-a-catastrophe

Valve Confirm ‘Steam’, ‘Left 4 Dead 2′ Coming to Ubuntu
http://www.omgubuntu.co.uk/2012/07/valve-confirm-steam-left-4-dead-2-coming-to-ubuntu


12.04 LTS, tried making bootable USB stick, Startup Disk Creator erased my backup drive!

How could it erase a disc that wasn't selected in the "Devices" dropdown?

It is a bug in  'startupdisk creator'. The list box in startup disk creator shows only the first usb device in the destination. But it selects the last device. So when you saw the destination you would have noticed your flash drive, but actually the 2TB hardisk was selected. This will be visible only when you scroll down or maximize the window.

What exactly did it do when it erased?

The program may have tried to erase or format the drive, but it couldn't do it due to some reasons and  it managed to corrupt the data by deleting whatever was possible like partition-table and has left the data to an unrecoverable state. Or maybe it might have even formatted the disk and deleted the data and left something to show up in the drive properties.

Is my data completely hosed?

Your data is gone forever and there is nothing you can do to retrieve them with the same folder structure. But you can use the recovery software like potorec, scapel, foremost, recurva etc. to get pieces of your data. Some recovery software might also retrieve you the 100% of data. But still that wouldn't be what you expected.

can I expect this long deep scan to bear fruit?

If you are referring to the deep scan in testdisk, then the answer is no.

But there is one important thing that you should do first. Get an empty hardrive of 2TB or more and make a clone of the affected one using dd command. This does not recover you data, it helps to have a backup of the affected disk. Do every experiments that you want to do using the different recovery methods only on the cloned drive.


SMART Disk Failure 05 - Reallocated Sector Count: Creating a Partition Ubuntu 12.04

As your drive has bad sectors it is likely that the drive will fail in the near future. It is therefore not recommended to further use the drive but replace it with a new one instead. Proceed only if you have not other choice or the drive will not hold any important data. Make sure your regularly back up this drive.

On installation of 12.04 (see this answer for screenshots) you will be asked how to use your disk. Choose Something else on the Installation type menu.

This will open Ubuntu's graphical partition manager from Ubiquity. In case you have already installed Ubuntu you will be able to run Gparted from a alive CD. For editing unused partitions we may install gparted .

  We assume that your drive does not contain any important data, is unmounted, and is ready to be repartitioned. Choose New Partiton Table to repartition your drive:

We then need to tell gparted the erroneous sectors assuming they are really at the beginning of the drive by selecting Add... and then choosing don't use the partition:

After that we may create the remaining partitions to hold Ubuntu, namely the Swap partition (in case we really need one):

And then at least the root partition (/) to hold the system files. We may also add a separate /home partition here (but this is not really needed anymore):

After we have set up the partition table we proceed with partitioning, formatting and installing Ubuntu to this drive by pressing Install Now:

  Note: In case you are unable to install Ubuntu or get errors when booting it may likely be that additional bas sectors have occured that will make the drive even less usable.


Into terminal type

sudo add-apt-repository ppa:gnome3-team/gnome3

Then:

sudo apt-get update && ssudo apt-get install gnome-shell

When these have finished, log out of ubuntu, click on the circle with the ubuntu logo near the password box, and choose one of the gnome options (you probably want just Gnome). It will always be the last chosen one by default (so after a restart, you can just log straight in).


Adding OpenMP support to compiler command line

It seems that mlpack is installed with OpenMP support, and you are trying to install MLPack Model Zoo without OpenMP support. Perhaps a bug in the makefile. Find the corresponding line in the makefile and add the OpenMP compiler flag (f.i. -fopenmp) where applicable.


Xen - install fully paravirtualized Ubuntu - no virtual kernel in bootloader

Turns out that the user can use 'manual package selection' at the apt/task menu in order to remove the generic kernels and install the virtual one instead.

You also have to ensure that you change the default partitioning from using ext4 to using ext3 for this to work. I don't know if it's a pygrub specific issue or not.

This manual package selection is pain. Worth looking into a way to use the minimal virtual install mentioned here:


No sound in KUbuntu 14.10, only Dummy output device listed

Thanks to Temüjin from ubuntuforums.org this issue has been solved! Temüjin wrote:

The needed firmware files used to be a part of the kernel, but got moved out for legal reasons in kernel 3.14:

https://github.com/torvalds/linux/co...c207f46cbcae03

This should fix you (reload alsa or reboot when finished):

cd ~
wget ftp://ftp.alsa-project.org/pub/firmware/alsa-firmware-1.0.28.tar.bz2
tar xjf alsa-firmware-1.0.28.tar.bz2
cd alsa-firmware-1.0.28
./configure
cd cs46xx/
make
sudo make install

Perfect! A little difference only: wget downloaded the compiled files also so the make command wasn't necessary


Does dual-boot negatively affect performance?

Setting up a dual boot does not affect the performance of a computer as only one operating system is running at a time. Thus, they get access to all of the computers resources. The only system spec which is affected is HDD space (not HDD speed) as the drive has been divided between the operating systems, thus, they only have access to the space allocated to them.


pam_tally2 not locking user out after failed attempts on Ubuntu 14 and 16

see Ubuntu_16.04
you need also add line account required pam_tally2.so to /etc/pam.d/common-account


tpm_tis Operation Timed out when booting 14.04 LTS

Press 'e' at boot menu. Add the command nolapic after ro in the boot options. You can add this to grub file:

Edit your grub.cfg and change

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nolapic"

Save file, then run update-grub.


Open Dash and search for power

Change your options as shown by the arrows.

N.B. since this is a beta - if the above does not work - file a launchpad bug report.


Brightness indicator in the panel icon missing

You can fix this problem changing the path to icon in file

  /opt/extras.ubuntu.com/indicator-brightness/indicator-brightness

check if this image file exists

  /usr/share/notify-osd/icons/gnome/scalable/status/notification-display-brightness-full.svg

create a backup

  cp /opt/extras.ubuntu.com/indicator-brightness/indicator-brightness /some/backup/folder

find the line you need to change

  ind = appindicator.Indicator ("indicator-brightness",
                                "/usr/share/notify-osd/icons/Humanity/scalable/status/notification-display-brightness-full.svg",

then replace it with

  ind = appindicator.Indicator ("indicator-brightness",
                                "/usr/share/notify-osd/icons/gnome/scalable/status/notification-display-brightness-full.svg",

That fixed my problem so I hope it will help you.


X11 Forwarding over Gnu Screen, is it possible?

To manually do this, once you have SSHed in, but before you reattach to screen, check your DISPLAY environment variable:

echo $DISPLAY

Once you have re-attached to screen, explicitly set the environment variable:

export DISPLAY=:N.0

where :N.0 is what the echo showed before the attach. This won't be perfect, since some application may be expecting to talk to the Session D-Bus, which is a bit more complex to send over the SSH connection.


UFW is blocking incoming connections to port 22. Run this to allow it:

sudo ufw allow 22/tcp


A simpler solution to running a program, IMHO would be to combine the --autologin flag of getty and a function that runs your desired commands from .bashrc .

Part 1: autologin to getty

As you may or may not know, TTYs are opened with a getty program as a startup service in /etc/init/ directory. For Ubuntu, default program is agetty, which has --autologin flag. Thus, we can do the following:

In terminal run sudo nano /etc/init/tty1.conf to open init file for TTY1 (notice that TTY1 is just an example, could be whichever you choose) . Change line

exec /sbin/getty -8 38400 tty1

to

exec /sbin/getty --autologin userName    -8 38400 tty1

Replace  userName with your actual userName.

Part 2: running a function on shell login

Linux/Unix systems have this nice little program called tty that reports what kind of terminal you are using at the moment. For instance, in gnome-terminal it would report something like

$ tty
/dev/pts/27

In TTY1 however it would report

$ tty
/dev/tty1

Knowing that we can create a function at the top of our $HOME/.bashrc file

function testTTY
{
  isTTY=$(tty | awk '{if ($0~/\/dev\/tty.*/) {print "true"}else{print "false"}}')

  if [ $isTTY == "true" ]; then
    printf "You are in virtual console\n"
    printf "current disk usage is"
    df
  fi
}

Then at the bottom of the .bashrc make a call to your function, simply as testTTY. So, define function first, call it later.

Side notes:

place custom commands between the if [];then ...fi
If you need specific TTY change isTTY code to this: isTTY=$(tty | awk '{if ($0=="/dev/tty1") {print "true"}else{print "false"}}')


Why does partition table corruption even happen?

I hope this may help you.
http://tutafuta.com/2011/03/15/partition-table-repair-reinstall-copy-for-future/


Clicks on the screen while laptop lid is closed

Disabling the touchpad solved it for me. If you or someone else have the same problem, try installing touchpad-indicator and disable the touchpad while the lid is closed.

sudo add-apt-repository ppa:atareao/atareao
sudo apt-get update
sudo apt-get install touchpad-indicator


How can I break out of ssh when it locks?

Normal keys are forwarded over the ssh session, so none of those will work. Instead, use the escape sequences. To kill the current session hit subsequently Enter, ~, ..
(Keep in mind that in international keyboards where ~ is set to be a composing character, you have to hit it twice: Enter, ~, ~, .)
More of these escape sequences can be listed with Enter, ~, ?:
Supported escape sequences:
     ~.   - terminate connection (and any multiplexed sessions)
     ~B   - send a BREAK to the remote system
     ~C   - open a command line
     ~R   - request rekey
     ~V/v - decrease/increase verbosity (LogLevel)
     ~^Z  - suspend ssh
     ~#   - list forwarded connections
     ~&   - background ssh (when waiting for connections to terminate)
     ~?   - this message
     ~~   - send the escape character by typing it twice
(Note that escapes are only recognized immediately after newline.)

You can close the list of Escape sequences by hitting Enter.
Notice that because hitting ~~ causes ssh to send the ~ instead of intercepting it, you can address N nested ssh connections by hitting ~ N times. (This only applies to ~s that directly follow an Enter.) That is to say that Enter~~~~~. terminates an ssh session 5 layers deep and keeps the other 4 intact.


The AMD drivers (Catalyst and fglrx) that were available in previous versions of Ubuntu are not available in 16.04 anymore. This is due to bad support from AMD for the Linux drivers. Only the Open-source driver can be used.

I stand to be corrected if some alterative way is known for installing AMD drivers.

The AMD graphics card supported by AMDGPU driver are listad in this link (for Ubuntu 16.04 look at 15.10 column) :https://help.ubuntu.com/community/RadeonDriver


How to set up a SFTP server with users chrooted in their home directories?

That article also describes how to get a chrooted shell access, but since you just want a sftp-only account, just follow these instructions:

Edit /etc/ssh/sshd_config and add the lines:

SubSystem sftp internal-sftp
Match Group sftp
ChrootDirectory %h
ForceCommand internal-sftp
AllowTcpForwarding no

Find the line UsePAM yes and comment it:

#UsePAM yes

Without disabling this, my SSH server would crash on reloading/ restarting. Since I do not need fancy functions of PAM, this is fine.

For extra security, restrict the users who can login. If you forget to add SFTP users to the sftp group, you give them free shell access. Not a nice scenario. Because SSH cannot combine AllowUsers and AllowGroups (a login has to fulfill both rules), you've to create an additional group, say ssh-users. Add the users who are allowed to login (youruser below) over SSH:

sudo groupadd ssh-users
sudo gpasswd -a youruser ssh-users

And add the next line to /etc/ssh/sshd_config:

AllowGroups ssh-users sftp

Now proceed with modifying the permissions of the users home directory to allow for chrooting (example user sftp-user):

sudo chown root:sftp-user /home/sftp-user
sudo chmod 750 /home/sftp-user

Create a directory in which sftp-user is free to put any files in it:

sudo mkdir /home/sftp-user/public
sudo chown sftp-user: /home/sftp-user/public
sudo chmod 750 /home/sftp-user/public

Should you run in any problems, check /var/log/syslog and /var/log/auth.log for details. Run ssh or sftp with the -vvv option for debugging messages. For sftp, the option must appear before the host as in sftp -vvv user@host.


How to disable the [HP] ACPI button for the wireless card?

Now that we know that the module hp_wmi is blocking the wireless, let's blacklist it. From the terminal:

echo "blacklist hp_wmi" | sudo tee /etc/modprobe.d/blacklist-hp.conf

Reboot and you should be all set.


Installing Tensorflow on Ubuntu Server 14.02

Steeldriver's comment above is a good start.  Try opening https://storage.googleapis.com/tensorflow/  in a browser.  You should get an XML page with a list of items.  Don't worry about the contents - the key question is whether you can successfully view the page.  If you can't, and you can post here, something's weird.  It's possible that you're behind a firewall or have a DNS problem.  A quick check for those would be to try to ping 8.8.8.8 (google's DNS servers) and/or set your DNS server in /etc/resolv.conf to 8.8.8.8, and then retry the download.


Can i install ubuntu touch on lenovo tab with ARMv7 processor

You can't install Ubuntu touch on Lenovo Tab.

Here are the supported devices:

http://developer.ubuntu.com/start/ubuntu-for-devices/devices/

How to install on some devices:

http://developer.ubuntu.com/start/ubuntu-for-devices/installing-ubuntu-for-devices/

Portings are coming soon, your best chance will be someone have the device and he did effort to port your device.

On the site they say: A new porting guide will be written shortly and be availble at Touch/Porting

https://wiki.ubuntu.com/Touch/Porting


You can copy system default files by using following command

cp -v /etc/skel/.bash* /etc/skel/.profile ~/

For Better my-user@server PS1 Prompt add folloing lines in your .bashrc

# When Commands Fail Turn PS1 In RED
PS1="\`if [ \$? = 0 ]; then echo \[\e[34m\]^_^[\u@\h:\w]\\$ \[\e[0m\]; else echo \[\e[31m\]O_O[\u@\h:\w]\\$ \[\e[0m\]; fi\`"

More Details: .bashrc


error: parsing file '/var/lib/dpkg/status' near line 55497 package 'indicator-displex'

After looking at the file mentioned in the error /var/lib/dpkg/status on line 55497, I saw this:

Package: indicator-displex
Priority: optional
Section: GTK, system, admin
Installed-Size: 1524
Maintainer: Arick McNiel <arickmcniel AT yahoo DOT com>
Architecture: all
Version: 0.1
Depends: python, python-gtk2, python-central (>= 0.6.1), python-notify, python-appindicator, compiz
Size: 130748
Description: DisPlex
 AppIndicator to interface with Compiz / Xrandr / Emerald.
 .
 The Displex (indicator-displex) application provides an AppIndicator to the display
 interfaces of Compiz / Emerald / and Gnome Display Manager.  In doing so, it hopes
 to provide a product that is helpful for those applications without an AppIndicator
 interface AND to minimize icons by combinine some functionality of the
 gnome-display-manger AppIndicator icon.

 DisPlex has the following features:
 -Uses the new Ubuntu AppIndicator interface
 -Provides interface for: COMPIZ, EMERALD, GNOME Display Properties
 -Enables you to change decorators from the AppIndicator Tray
 -Enables you to activate / deactivate Compiz Effects
 -Enables you to switch window manager
 -Provides the ability to hide/show desktop icons
Homepage: https://launchpad.net/displex; http://sourceforge.net/projects/displex/

I made a backup of this file, and then opened it in a text editor. (sudo vi /var/lib/dpkg/status, then :55497 to go to that line.)

Adding a single . to the blank line before "DisPlex has the following features:" fixed the problem.

(if unfamiliar with vi... here's a hint: A to append line, add a space & period ESC to exit insert mode, then :wq to write & quit)

I was then able to run sudo dpkg --configure -a.  After running sudo apt-get -f install, I saw a similar error for the file /var/lib/dpkg/available.  I added a single . to this file on the line mentioned in the error, and now it mostly works.

I ran into one last problem which is the same as this bug.

Unpacking libatk-adaptor-schemas (from .../libatk-adaptor-schemas_2.4.0-1ubuntu2_amd64.deb) ...
 dpkg: error processing /var/cache/apt/archives/libatk-adaptor-schemas_2.4.0-1ubuntu2_amd64.deb (--unpack):
  trying to overwrite '/usr/share/glib-2.0/schemas/org.a11y.atspi.gschema.xml', which is also in package libatk-adaptor 2.2.1-0ubuntu1
ErrorMessage: trying to overwrite '/usr/share/glib-2.0/schemas/org.a11y.atspi.gschema.xml', which is also in package libatk-adaptor 2.2.1-0ubuntu1

To fix this problem:

sudo apt-get update
sudo apt-get dist-upgrade


upload freeware program to ubuntu software center

You can't just upload to Software Center, you need to have your app evaluated, and then once approved, it will be published.

See Ubuntu Developer


For some reason file managers give an error when you access trash icon with sudo (caja and thunar do that also). Also there is a chance that trash permissions has changed (never run file managers and gui applications in general with sudo, use gksu or pkexec instead) and maybe that's why you can't empty trash with no sudo rights. In order to be sure, delete the folder ~/.local/share/Trash and it will be recreated empty on reboot (if you are sure there's nothing wrong with permissions just delete specific files in ~/.local/share/Trash/files folder).


Why does Alt+F1 lock the computer, and how do I get back the old behavior?

Do you have an 'F-lock' key or something similar that you may have accidentally pressed? It sounds like the hardware intercepts the keystroke before the OS...


Wrong command. You need to change owner and group to 'root'.

chown root:root /path/to/directory

And if you want to harden it even more put the 'immutable' on it with

chattr -i /path/to/directory

(only 'root' can set this back).

chmod 000 /path/to/directory

only removes permissions but it is still owned by the user (and the group it belongs to). It does not make it only for 'root'. Removing permissions from a directory makes in non-executable and for someone to enter it you need that set.


After much digging I found out Alsa does recognized my mic and Pulseaudio does not, not sure why.
But I combined several steps that solved the issue for me:

I removed Pulseaudio:
sudo apt-get purge pulseaudio
sudo apt-get purge pavucontrol
rm -rf ~/.pulse/

Reboot (after rebooting, no input or output device were found).

Add the following to /etc/modprobe.d/blacklist.conf
blacklist snd_hda_intel
blacklist snd_soc_skl

Add the following to /etc/pulse/default.pa (note replace the device with your own device address)
load-module module-alsa-source device=hw:0,0

Reinstall Pulseaudio:
sudo apt-get install pulseaudio

Reboot.

After finale reboot all input and output devices were working including internal Mic and Audio.

Part of the solution was taken from here.


Wireless adaptor problem after upgrade from 12.10 to 13.04

The wl driver is currently loaded for the adapter, you need to remove that first:

sudo apt-get purge broadcom* bcmwl*

The firmware for this card is installed the following way:

sudo apt-get install firmware-b43-installer

After a restart the b43 driver should get loaded for the adapter, you can check it with lshw -C network.


I've just put a 32GB verbatim SD card in my EeePC 900SD and have it mounting as /home.  It's working great.  I did delete the partition table and remade it with gparted as I've seen problems with Verbatim partition tables on SD cards and USB sticks.

Have a look at the this question and my my answer for possible reasons for the problem and the solution.

In particular you might try this test from that that answer to verify the problem:

Running fdisk -l on the thumbdrive will often declare that it has no partition table, even though you know there is one and can write data to it if it is still mounting OK.

If you have a 900SD or similar I can recommend using the SD card to mount as /home, since the SSD is generally only 8GB - fine for Ubuntu but a bit tight if you store any work or data on it at all.


Cannot change desktop background with crontab

Here is my version of your script. By this approach we do not need to worry which environment variable we should export, because we exporting all available variables for the current user's session.

#!/bin/bash

# NAME: lubuntu-wp-changer

# Initial variables
ITEMS_PATH="$HOME/Pictures/wallpapers"
ITEMS=("$ITEMS_PATH"/*)

# Check whether the user is logged-in, if yes export the current desktop session environment variables
[ -z "$(pgrep lxsession -n -U $UID)" ] && exit 0 || export $(xargs -0 -a "/proc/$(pgrep lxsession -n -U $UID)/environ") >/dev/null

# Generates a random number in the range determinated by the number of the items in the array ${ITEMS[@]}
ITEM=$(( ($RANDOM) % ${#ITEMS[@]} ))

# Set the wallpaper
pcmanfm --set-wallpaper="${ITEMS[$ITEM]}"

exit 0

Here is my Cronjob that changing the wallpaper every three seconds:

* * * * * bash -c 'for i in {1..20}; do $HOME/lubuntu-wp-changer; sleep 3; done'

Here is the result:

More details could be found in my GitHub project: cron-gui-launcher.


How can I re-partition after Installation (dual boot)?

I am unsure if the partitions can migrated/ but if you go for a fresh install folloing  a simple/general approach to squeeze performance for VM usage:

on SSD:

/boot - This should exist on ssd to improve Boot Time (Q: are you planning to restart the machine once its up and running often, if not this belongs in the HDD)
/swap - This is paging memory being treated as RAM which, super essentail to have this here for VM runtime performance, multitasking, large applications
(use the rest of the SSD space for rest of the OS files)

HDD:

All VM users that get created can have their /home dir mounted from the HDD


Try to change the default program in the Preferred applications, you should find Lotus notes in the drop down list .


Unable to locate package libesd0-dev on Ubuntu 18.04

From Ubuntu 18.04 libesd0-dev is deprecated. For this you need to add repositories of xenial, i.e. repository of a previous Ubuntu release which is still supported, in sources.list.

Open Terminal and run:

sudo nano /etc/apt/sources.list

A list will be opened in nano. Copy and paste these two lines at the end:

deb http://us.archive.ubuntu.com/ubuntu/ xenial main universe
deb-src http://us.archive.ubuntu.com/ubuntu/ xenial main universe

Save and close using Ctrl + C. Then run:

sudo apt-get update && sudo apt-get install libesd0-dev


It is very much possible to have LVM at the time of install itself. Infact that's a preferred way also. Please refer to this thread

In case you have already running system - you can have lvm at that time also


To install Java 7:

sudo apt-get update
sudo apt-get install openjdk-7-jre

sudo apt-get install icedtea-7-plugin

How do I install Java?


Seems you can't use G4L to image to a USB drive formatted to FAT32... apparently the dang thumb drive I got yesterday was formatted FAT32 and I forgot to check before wasting HOURS trying to write my VISTA64 image on it. That's why the File too large error - too large for FAT32...

...so, REFORMATTED the USB drive to NTFS, and the backup using G4L is working fine...

*Found Clue HERE: https://forum.proxmox.com/threads/backup-error-lzop-file-too-large-stdout.19315/