The package dhcp3-server was renamed some time ago to isc-dhcp-server.

apt-cache search dhcp.-server
isc-dhcp-server - ISC DHCP server for automatic IP address assignment
dhcp3-server - ISC DHCP server (transitional package)
...

Installing either dhcp3-server or  isc-dhcp-server will have the same result.

apt-case show dhcp3-server |grep ^Depends
Depends: isc-dhcp-server


Hp 11 Stream Celeron N4000 Virtual Machine PAE error

The only time you need to use PAE with virtualisation is if you are setting up a virtual, 32-bit OS and:

you need more than 4GB of memory (RAM) to be allocated for the VM
you need to be able to access parts of memory that cannot be used for executable code

In both cases, more than 4GB of RAM needs to be allocated to the VM, meaning at least 5GB needs to be installed on the machine (taking into account the shared memory for video) in order for PAE to be properly enabled within the VM. Googling the types of computers that used the Celeron N4000, most shipped with 2GB and others capped out at 4GB. Unless your machine is one of the rare ones with 8GB (the maximum supported by the N4000), PAE is not going to work.


How can I transfer Ubuntu from a stick to a new SSD

You can use dd to clone the USB stick to SSD.

dd if=/dev/sdx of=/dev/sdy

Where sdx is the drive you wish to clone from and sdy is the drive you wish to clone to.

This can be dangerous if you are not expert with dd, Google before proceeding.

What are you using on the USB, a Full install or a Persistent install?

A Persistent install has limitations when used as a main o/s, such as inability to upgrade and update. You would also need to make an ext4 casper-rw partition to get more than 4GB of persistence.

If you are using a Full install you can expand partition size after cloning.

If you do not wish to use dd, you can copy using rsync, grsync is a gui version.


Can not login after removing broken packages

First thing I'd try is:

press CTRL + ALT + F1 to access a terminal and log in with your admin account.
sudo dpkg --configure -a
sudo apt-get update
sudo apt-get autoremove
sudo apt-get dist-upgrade
reboot


Apparently systemd-u is an alias for systemd-udevd.service. This can be stopped using:

systemctl stop systemd-udevd.service

However, it seems like the service is restarted automatically by systemd-udevd-control.socket and systemd-udevd-kernel.socket. When I stopped those two using systemctl the problem was resolved. When finished imaging the disk, it's probably a good idea to restart the services.


Cannot type in the first instance of an app

Maybe that you can fix the problem by running the command sudo apt-get update and rebooting your machine. If it still doesn't work, you could then try uninstalling the program(s) and reinstalling it/them. You could also check for keyboard drivers (even though Linux is Plug-and-Play), or if your computer is slow, because it could be some kind of lag. Also go to the update manager and install the 16.04LTS latest updates and reboot. If everything above still doesn't work, you could still try installing another version of Ubuntu (e.g. the previous LTS version) and testing everything making sure you do the things above.

Hope it helped,
Js


I've been searching for a while now, and was disappointed to see no answers to your question.  Here are the best I've found so far, one of which you mentioned:

http://cloudinit.readthedocs.org/en/latest/topics/examples.html
https://help.ubuntu.com/community/CloudInit

You can override anything in /etc/cloud/cloud.cfg, too, so that can be a useful example.

Edit: This is probably the example you were talking about.  According to multiple sources, it should be mostly complete.  Here's the full list for anyone else who hasn't found them yet.


The host of that file at http://www.tatanka.com.br now advises

"The new Internet Explorer and Edge can not be run on Wine anymore"

Instead, they recommend

"So Microsoft has its own VMs for this:"

https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/

"Virtual Box, vagrant, VMWare and others are supported."


how do I get my partition to mount in the file manager?

More details would help. Work as user root.

[user]$  sudo su -
password for user:
[root]#

I assume you have just created this partition and then you formatted it with ext4.

IF this is the correct point of entry, you need to create a directory, mount the file system against this directory, and optionally add this to /etc/fstab to have the system mount this at every reboot.

fdisk   -- creates partitions, skipped details here

mkfs.ext4  -- formats the partition: shown below

[root]# mkfs.ext4   [-L  DeviceLABELname] /dev/sdb2
 [.. lots of output truncated ..]

Connect the newly formatted partition to the file system:

[root]# mkdir /data ; mount /dev/sdb2 /data  ;  df -h /data

This should show the mounted file system information.

Create entry to reconnect this partition at every reboot
[NOTE: if this is a USB device that will be removed and inserted,
do NOT perform these next steps. Instead, pull it out, push it
back in.]

[root]# echo '/dev/sdb2 /data  ext4   defaults  1 2' >> /etc/fstab

[root]# umount /data ; mount -a    # disconnect, remount from /etc/fstab

FOR A USB DEVICE, suggestion add label to device, system will automatically
mount the device when it is inserted.

/dev/sdb2  implies there is another partition ahead of this one, such as
/dev/sdb1  which, if on a USB device, could be a different format.

[root]# mkfs.ext4   -L  BCK250GB  /dev/sdb2

This puts the label BCK250GB on this partition.

* NOTE ABOUT REMOVABLE MEDIA
IF there are 2+ partitions, and the other one is already discovered,
then it will be mounted. Bring up the graphical file manager tool and
click on the funny triangle just left of the name to 'eject' the
device safely. This should be done FOR ALL USB PARTITIONS before you
remove the device.  *

Pull this USB device out and plug it back in ONLY IF all other partitions
have been 'ejected' (which means umounted in Linux/UNIX world).

This should force the local GRAPHICAL system to see the device.

IF THIS IS A SERVER version of Ubunbu with no graphical interface ..
.. the above is not quite right, you have to do all the manual
steps above and use the 'df' command to see if it is mounted or not.

Last thing, get out of ROOT LOGIN, do not work as root unless you
have to.

[root]# exit
[user]$
Good luck.


How to record internal audio with XVidCap? (not with microphone)

I found the solution in this blog post:

  Uninstall xvidcap in Synaptic
  Install xvidcap from here on Sourceforge
  [editor's note - this is a very old version (deb is for Jaunty) - not recommended. I doubt
  this solution is still valid]
  Lock the installed version in Synaptic
  Install pavucontrol in Synaptic
  Open the program with padsp xvidcap
  Click on the recording button (red circle)
  Run pavucontrol, go to the Recording tab and there choose Monitor of Analog Stereo Internal Audio

  Done!!

  To record with sound, the program has always to be run with padsp
  xvidcap (for example from ALT+F2). To run it always like that from
  the menu: run alacarte, go to Sound and video, then to XVidCap
  Screen Capture > Properties and where it says Command put padsp
  xvidcap.

I would add this:

The above is to record system sound, that is, whatever is coming out of the speakers, which can be of a song or movie of our hard drive or pendrive played by Totem, of a Flash music video of a website played by Firefox.

Nevertheless, sometimes it can be necessary to record the microphone sound, for example if we want to make a video tutorial to explain how a program works. In this case we put xvidcap in recording state, run pavucontrol and in the Recording tab we put Analog Stereo Internal Audio (without "Monitor of").

If we only want to record sound (without video) we can run from ALT+F2 gnome-sound-recorder. The first time probably it will be configured to record from the microphone. To record the system sound we run with ALT+F2 gnome-volume-control, go to the Hardware tab and in Profile we put Analog Stereo Output (it's also possible to do this running pavucontrol and using the Configuration tab).

But when we finish we have to put again Analog Stereo Duplex in the Profile of Hardware of gnome-volume-control (or of Configuration of pavucontrol), so we can still choose the origin of the sound when recording with xvidcap.

NB: sometimes, to change from Analog Stereo Duplex to Analog Stereo Output it may be necessary to change first to Off, close, open again and then change finally to Analog Stereo Output. The same for the opposite change. If not, the computer may "not notice" that we have applied the change.

Taken from this post on Ubuntu Forums


Boot-repair won't install "unable to locate package"

The PPA has no version of boot-repair for Ubuntu 11.10, you should try it with a newer release of Ubuntu. Ubuntu 11.10 has no support from canonical anymore since 9 May 2013 so it seems a good idea to upgrade anyway.


How to open file with extension .crdownload?

It depends on what you are trying to get out of a *.crdownload. It mostly contains metadata for Chrome to be able to restart the download.

You could use strings to read the printable character from the file like so:

$ strings 461304.crdownload

But that isn't going to tell you a lot if it is something like an image or song.

To actually restart the download, you can open it in Chrome.


Sharing Wifi connection over ethernet, Still no internet access

I have now fixed my problem.
I added

nameserver 10.42.0.1

to my resolv.conf file on the beagle bone and can now ping and run apt-get update.


"Folder view" is reset to desktop when monitor is connected

I have resolved it by using more recent KDE version. This is done by adding Kubuntu Backports PPA to software sources:

sudo add-apt-repository ppa:kubuntu-ppa/backports
sudo apt update
sudo apt full-upgrade

In theory your system might get less stable, but I've been using it for a week and haven't experienced any problems or crashes.


Bash terminal to list commands from folder containing text files

You can use this as a template:
#!/bin/bash

menu () {
echo "Please choose a command below"
echo "  1)Print Present workind directory"
echo "  2)echo hi"
echo "  3)Clear screen"
echo "  4)Exit menu"
}

menu

while read n

do

case $n in
  1) echo "$PWD";;
  2) echo "hi";;
  3) clear;;
  4) exit;;
  *) echo "invalid option. Please try again";;
esac

menu

done


If I understand you correctly, you are compiling a kernel and want a graphical tool to review the configuration ?

Install the dependencies

sudo apt-get install libgtk2.0-dev libglib2.0-dev libglade2-dev

Then to use it you

make gconfig


Why is 'S' the 'W'orkspace switcher and 'W' the 'S'cale plugin?

I've memorized them as  W indow list and S witch workspaces.


how to run a service a non-root user completely?

How is your screen shot relevant?  You're showing the user and directory of your shell.  I could misunderstand, but I think some confusion lies here.

The SystemD service you have should start when you boot the machine, as the dev001 user.  You can find this using systemctl or ps aux | grep vsc.sh or similar.  The key here is not to look at your shell, but the owner of the actual process.

sudo systemctl enable vsc.service
sudo systemctl start vsc.service
sudo ps aux | grep vsc

You should see that your service is being run by the user set in your vsc.service file.


IBS Chinese pinyin input candidates appear at bottom of screen

To solve the ibus pinyin candidate appear at bottom of some application, You need to install extra packet, which I think is ibus-gtk.

Synaptic Package Manager -> search for ibus -> Mark recommended for installation -> install ibus-gtk and log out.


app icon still showing after purge/uninstall

Any icon you see in the application launcher is represented by a desktop launcher file in specific directories. That are specifically formatted text files with the .desktop extension. Removing such launcher will remove the icon from the menu.
Normally, removal of an application installed via APT or snap or flatpak will also remove the system installed desktop launcher. If an application launcher remains in the application menu, then it would not be displayed in the menu if the command to execute it has become invalid. This command is provided on the Exec= line in the launcher.
Thus, if I see and the launcher and specific icons for them, then my first impression is that your application is not removed, or not completely removed.
Apart from the question whether the app is removed or not, you can manually remove the icons in the application menu by locating the desktop launcher files and deleting them. The command
find / -name '*.desktop' -exec grep -H "Name=Ozeki" {} \; 2>/dev/null

will list any desktop launcher that displays a label starting with "Ozeki" in your menu.
In your case, also icons have been left behind. You can identify the name of the icons by looking at the Icon= line in the desktop launchers, and then find and delete the icon files if you wish so.


how to switch back to ATI card after using switcheroo?

Have you tried with echo DDIS > /sys/kernel/debug/vgaswitcheroo/switch?

It works fine on mi laptop with AMD5650/Intel Switchable graphics.


Failed to install flatpak on Ubuntu 18.04

The problem got solved once I connected my router cable directly to the pc, without the Wifi. Still i believe some bug may be present with the flatpak  download manager.


blank screen on ubuntu server 14.04 on PC

Yes, The problem is about Raid.
When I remove the Raid, My Ubuntu server loaded without any problem.
I have a new question about it, How can I have Ubuntu server 14.04 with Raid, Because without raid is unreasonable way.
I know boot drive should be without raid only, But I don't know how can do it.


crontab edit produces a number and does not open the editor in ubuntu 16.04 server

crontab gets opened with the default editor, which is saved in the EDITOR environment variable.

for me, this is vim:

$ echo $EDITOR
vim

You can run crontab overriding the default editor like this:

EDITOR=editor-of-your-choice crontab -e

to permanently select a default editor, you can simply run this and choose the right number:

select-editor

then, crontab -e should now open with your editor of choice.

See this related question: Changing default crontab editor


How to install FreeFileSync in Ubuntu 16.10?

Open a terminal (CTRL+ALT+T)
Run these commands:

cd ~/Downloads/FreeFileSync
./FreeFileSync              #I haven't used this program, so I don't know if it requires arguments or not

Note:

If you are running a 64-bit version of Ubuntu, and you are trying to run a 32-bit compiled program, you will need to install the 32-bit libraries.

EDIT:

To fix the errors you are getting, try running:

LD_LIBRARY_PATH=/usr/local/lib64/:$LD_LIBRARY_PATH
export LD_LIBRARY_PATH
sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get install gcc-4.9 g++-4.9

And then try step #2 again.


Is there a way to add a main menu button to the unity panel?

Actually, there is a main menu button on the dock called applications (dark grey lower half) if you right click you will get the typical main menu entries and then the dash format opens. I would be also happy if I could move this "icon" to the top in case I dont remember (happens I am over 50) the name of the app and want to use my graphical memory by switching to classic view (like in windows). Bottom line, the functionality is there, just lets hope a more knowledgeable person will enable us to move this function to the place where we want to see it.


Photoshop is not working on wine, some solution like minimal windows in virtulabox?

Install Windows 10 as a Virtual Machine to run Photoshop in Ubuntu.

There is not a lot that you can do to Windows to make it run faster in VBox except to disable background applications and virus protection*, (if you are brave).

There are things that you can do to your Hardware, Ubuntu, VirtualBox and Photoshop to make Photoshop in a Windows guest run faster.

Hardware:

Add RAM
Add a fast SSD dedicated to Ubuntu.
Add a faster CPU
Add a better GPU
Ensure Intel VT-x or AMD-V Is Enabled

Ubuntu

Keep Ubuntu updated
Use lightweight desktop alternatives
Monitor startup apps
Do not add unnecessary software
Get rid of heavy startup applications
Increase Swap Space if you can not afford RAM
Enable Proprietary Drivers
Clean out old files
Reduce the default grub load time
Install preload to speed up application load time

VirtualBox:

Create your machine using a fixed size disk
Allocate more memory
Install Guest Additions
Install Extension Packs
Enabling copy paste
Increase display memory
Allocate more CPUs
Ensure Intel VT-x or AMD-V Is Enabled
Enable 2D / 3D Acceleration
Suspend Instead of Shutting Down
use the Intel PRO/1000 network drivers if using a network
Some people report VirtualBox being faster, while others report VMware being faster

Photoshop

Set performance-related preferences

Adjust the memory allocated to Photoshop
Adjust cache levels
Limit history states
Set graphics processor (GPU) settings

Fine-tune Photoshop features for performance

Work within file-size limitations
Close unnecessary document windows
Reduce patterns and brush tips in presets
Minimize or turn off panel preview thumbnails
Change file compatibility options
Work in 8-bit image mode
Turn off WYSIWYG font preview
Reduce image resolution
Purge the clipboard
Use the Filter Gallery
Drag between files rather than copy and paste
Use layers wisely
Save TIFF files without layers
Don’t export the clipboard
Disable the Libraries panel
Disable Device Preview
Disable Generator
Disable Rulers
Disable Font Preview
Restart the Creative Cloud desktop app
Use A Scratch Disk
Use 64-bit Architecture

*Benchmarking with Novabench, disabling virus protection in Windows did not have any effect for me.


No sound on music players, YouTube videos etc. Only get system sounds

Firstly, as Saurav Kumar mentioned in this comment Open System Settings from dash and click Sound Then go to Hardware > Profile and test other profiles that match your audio connections. You should test while running some media player.
If it will not work, then look at Ubuntu's page about sound problems: Sound Troubleshooting or better yet, the more recent help wiki page.


It's installed, it's just a mixer issue. To fix:

Run alsamixer
Set "Digital Input" option to "Digital Mic"

More: http://www.linlap.com/wiki/dell+studio+xps+16


How to play mp3 files from the command line?

For wav you can use aplay.  For mp3 you can use mpg123.


3 monitors (vga, dvi, hdmi) recognized, but no image on HDMI

It looks like you're trying to use three monitors on one card which, as far as I know, isn't possible. Like you're experiencing, the third monitor will be recognized, but trying to enable it either won't work, or it will disable the non-main (secondary) monitor. It's not a driver problem or a problem with Ubuntu, it's just not possible.


Scanner doesn't work anymore on ubuntu 18.10

gscan2pdf downloadable from the Ubuntu Software Centre often cures problems where other scanners fail to work.


New install times out Ubuntu 16.04.1 Server

Have you tried booting an older kernel? Hold shift while booting and select an older version. You can also try recovery mode from the same screen.


Installed Xubuntu on XP system but cannot boot it

grub is the program that starts Ubuntu. It needs to be installed and the partition needs to be marked bootable. Otherwise your computer will ignore it.

This is a common issue when someone installs Windows for instance, so how to fix it has been answered before: How can I repair grub? (How to get Ubuntu back after installing Windows?)


Interrupted Ubuntu 14.04 upgrade, Dual Boot

Yes. Put the live iso on your Usb-stick.
Install Ubuntu 14.04 on top of 12.04, dont format anything- this way you retain your personal files.
After installation reboot and update, the new installation will probably find your old programs and update them too.
Best of luck!


The netboot installation method is not different between Desktop and Server for Ubuntu: you should be able to install either environment from the same installer (or, in fact, any flavour of Ubuntu).

Netboot installers are found either at

http://archive.ubuntu.com/ubuntu/dists/${RELEASE_CODENAME}/main/installer-${ARCHITECTURE}/current/images/

or

http://ports.ubuntu.com/ubuntu-ports/dists/${RELEASE_CODENAME}/main/installer-${ARCHITECTURE}/current/images/

depending on your architecture. I am unable to help with the anna error: my apologies.


How to remove the trailing spaces in the output file when paste command is used?


Your GRUB entry for Windows is appropriate for a BIOS-mode boot, but not for an EFI-mode boot. This is a GRUB bug. You can try replacing the entry with something like the following:

menuentry "Windows 7" {
    insmod part_gpt
    insmod chain
    set root='(hd0,gpt5)'
    chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}

I make no guarantees that this will work, but it might. If it does, add that entry to /etc/grub.d/40_custom so that it will be created again whenever Ubuntu updates its GRUB configuration.

Another option is to use a different boot manager in addition to or instead of GRUB. rEFInd, for instance, will auto-detect both Windows and GRUB; and if you're using 3.3.0 or later kernels (as shipped with Ubuntu 12.10, but not with Ubuntu 12.04), you can boot Linux directly with rEFInd, bypassing GRUB entirely. gummiboot is another option with similar boot capabilities, but it requires more manual maintenance if you wanted to boot Linux directly with gummiboot.


Using shell find all sub-directories that contain certain files

If I understand correctly what you want to do, this is the solution:

#!/bin/sh

USAGE="Usage: $0 dir file1 file2 ... fileN\nto find all subdirectories of dir that contain all the given files.\n"

if [ "$#" == "0" ]; then
    printf "$USAGE"
    exit 1
fi

ARG=""
DIR=$1
shift

while (( "$#" )); do
  ARG="$ARG -exec test -e \"{}/$1\" \; "
  shift
done

cmd="find $DIR -type d $ARG -print"
eval $cmd

What it does is this:

The use find ... -type d to find all subdirectories (including the directory given as first parameter).
The test -e command checks if a file exists. So for a given directory we have to check all the files given in the command line:
    test -e /path/to/directory/file1
    test -e /path/to/directory/file2
    test -e /path/to/directory/file3
    ...
The /path/to/directory is {} - a single result of find. Then the find-parameter -exec can be used to check for a single file. To check for all files several -exec test parameters are needed. So while loop build a list of there parameters, then this list is put together in a single command and evaluated.

Have fun ...


At poweron, a PC will run a Power On Self Test (POST). An OS can't stop or break that.
Your hardware is faulty. Since you cannot find the fault, replace the hardware.
The update seems like coincidence.


KDE Plasma Install is Stuck - plasma-desktop package cannot be installed

I had the similar problem.

Try the following command:

sudo dpkg -i --force-overwrite /var/cache/apt/archives/plasma-desktop_4%3a5.6.5-0ubuntu1~ubuntu16.04~ppa1_amd64.deb

sudo apt-get -f install

This should do :)


As suggested in the duplicate, you can simply use:

sudo apt-get install wondershaper

In terminal find out what is the name of the interface connected to your internet by using ifconfig. Could be eth0, wlan0, etc... In my case is wlan0. So I would do this:

sudo wondershaper wlan0 1024 256

This will give me a download speed of 1024 Kbits and 256 Kbits upload, which is 128KB and 16KB.

You can reset your card with this:

sudo wondershaper clear wlan0

NOTE: That will limit ANYTHING in your PC, for example the torrent downloader, firefox, etc..


Java JNI call FindClass fails from a C++ program

This can occur if you have multiple versions of the JDK on your system, and the default Java version for the javac class compiler is different from the libjvm.so with which you are linking your executable.

For example, on my 18.04 system:

$ update-alternatives --list javac
/usr/lib/jvm/java-11-openjdk-amd64/bin/javac
/usr/lib/jvm/java-8-openjdk-amd64/bin/javac

and

$ javac -version
javac 11.0.6

then

$ javac MyTest.java
$
$ LD_LIBRARY_PATH=/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server ./SearchEngineCpp
JVM load succeeded: Version 1.8
ERROR: class not found !

You can work around this by calling the appropriate java compiler explicitly ex.

$ /usr/lib/jvm/java-8-openjdk-amd64/bin/javac MyTest.java
$
$ LD_LIBRARY_PATH=/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64/server ./SearchEngineCpp
JVM load succeeded: Version 1.8
Class MyTest found
Hello, World in java from mymain
777

For a persistent system-wide solution, use the update-alternatives mechanism to choose the appropriate Java version:

sudo update-alternatives --config java
sudo update-alternatives --config javac
sudo update-alternatives --config javap


Ubuntu 20.04 background -- is there a way to make the screensaver rotate/change every five minutes?

Welcome to Askubuntu!
To change screensaver every 5 mins:
Go to super > type Screensaver >  click on (In my case its a monitor icon with a moon) Screen saver  Prefs. > there you can customize the time, picture, type of screensaver, etc.
Hope this helps!
Regards.


How to use Snap Packages when $HOME is not /home/$USER?

snapd developer here

I'm sorry that this is a problem for you, because you didn't give details about the version of snapd you are using (tip, run snap version and paste that here) or the detailed arrangement of what your real home directory is on (it sadly also matters).

I haven't personally tried this myself but you should be good enough with a bind mount like this:

sudo mount --bind /some/random/place/home/zyga /home/zyga

You can make this permanent if you add it to your /etc/fstab file. After this you must also change your home directory to really be in /home/zyga and not in the original location.

If this fails please snap install hello-world and add the output of the following commands:

SNAP_CONFINE_DEBUG=yes hello-world
dmesg | grep DENIED


(Edit question and provided answer from OP)

I initially installed with network connectivity and it downloaded updates. I re-installed and shut off network connection during installation and I no longer have issue. However, I'm worried that when I update I'll run into an error again. Will edit this post after update if same error re-occurs.


Exec this command to see mounted partitions:

mount

Executing
mount | grep sda4 will filter to device you want to search for.

If the output of this one is empty, then it's not mounted.

We concluded by this way that df -h will show only mounted partitions.


I'm running on a nVidia card as well and it works for me.

Try reinstalling Skype and updating the nVidia drivers. Then when in a Skype call, click the blue video icon and then click "Start my Video".


Ubuntu 13.10 and Dell Inspiron 7520 SE (Intel 4000 and ATI radeon HD 7730m)

Sorry for my poor English.

If you can boot to login screen, then you don't have to reinstall your OS. You can only uninstall your AMD graphics proprietary driver to solve it.

In login screen, press "CTRL + ALT + F3" into command line, and login with your username.
Then use this command to uninstall your driver:

sudo apt-get purge fglrx*
sudo reboot

If it works, then you can try Install the driver with this command

sudo apt-get install fglrx-updates fglrx-pxpress
sudo reboot

But because of current compatibility issues, sometimes it is possible boot to "the screen went black with only the 'x' cursor showing". You can try it, or not for now and wait for some time before AMD improvement the driver.

Then about brightness problem. You can try

Brightness issue in a Lenovo ThinkPad Edge LR236W5 or

http://lists.debian.org/debian-x/2012/06/msg00082.html


The watch command with shell not recognizing filenames

watch executes commands with arguments by passing them to sh -c, so what you end up running is:

sh -c 'bash -c du -h /etc/passwd && df -h'

The shell you're running removes the first layer of quotes you applied.
The -h, /etc/passwd are then passed as $0 and $1 to bash, so they're effectively ignored. Run something like:

watch 'du -h /etc/passwd && df -h'
watch "bash -c 'du -h /etc/passwd && df -h'"

To verify, using strace:

strace -fe execve -o log watch bash -c 'du -h /etc/passwd && df -h'

And log contains:

17132 execve("/usr/bin/watch", ["watch", "bash", "-c", "du -h /etc/passwd && df -h"], [/* 40 vars */]) = 0
17134 execve("/bin/sh", ["sh", "-c", "bash -c du -h /etc/passwd && df "...], [/* 42 vars */]) = 0
17135 execve("/bin/bash", ["bash", "-c", "du", "-h", "/etc/passwd"], [/* 42 vars */]) = 0
17135 execve("/usr/bin/du", ["du"], [/* 42 vars */]) = 0
17135 +++ exited with 0 +++


Will installing Matlab on Ubuntu 12.04 Desktop open any ports?

Do not worry about MATLAB impacting the security of your Ubuntu installation, with regards to firewalls and public WiFi.

MATLAB will open TCP ports for certain things (esp. to verify the license is valid,) depending on how it is configured and how it is used. Normally, MATLAB does not act as a network server, which is what most basic firewall configurations are concerned with.

Running MATLAB wihtout a firewall is not likely to be a security risk, unless your MATLAB script is accessing sensitive data from a remote location. If you work with sensitive data, and this is your concern... do not use public WiFi. A firewall will not help you in this case.

If you are concerned about your computer being compromised as a result of using MATLAB without a firewall, then you do not need to worry.


change ownership of all files from root to user

Just go to the directory you want to change:

cd /opt/lampp/htdocs

and change the permission using the chown command:

sudo chown userName -R codeigniter

Where userName is the username and codeigniter is the folder's name.


How to send a zip file containing bunch of pdf's directly to a printer?

If you want a simple "one liner", you can use the -p option of unzip

  -p     extract files to pipe (stdout).
            Nothing but the file data  is  sent  to  stdout,  and  the  files  are  always
            extracted in binary format, just as they are stored (no conversions).

So it's a matter of piping the output to lpr:

unzip -p archive_with_lots_of_pdfs.zip | lpr

and you can easily adapt the script you linked to use this command.

Note that the -c option is similar

  -c     extract files to stdout/screen (``CRT'').

But it prints the filename before the actual content. This will break your lpr command and probably will print garbage.


do this:

sudo mkdir -p /etc/systemd/resolved.conf.d
printf "[Resolve]\nDNSSEC=no\n" | sudo tee /etc/systemd/resolved.conf.d/no-dnssec.conf

and restart


Which is the best windows emulator for ubuntu 14.04?

You can just run a partition with Windows installed as a second OS. It's not hard to do. I actually came from the other side, starting with Windows and partitioning to download Ubuntu 14.04


You have keepassxc installed twice.

snap install as version 2.3.4
deb install as version 2.5.1

You need to remove the older snap version.

sudo snap remove keepassxc


You can try my secure-mount.py wrapper script (see here: http://memobadz.wordpress.com/2013/12/06/encrypting-directories-using-ecryptfs/ )

secure-mount.py --import /home/.ecryptfs/USERNAME
secure-mount.py --mount  /home/.ecryptfs/USERNAME

=> put in the password you were using on that machine.

(No need for root)

You should be able to see your files in /home/.ecryptfs/USERNAME

Good luck.


You can fire up a terminal and locate the boot logs. They are usually (as well as other logs) in /var/log directory. An ls | grep boot in that directory in my machine brings up two files. One called boot which doesn't have anything in it and another called boot.log which seems to include the messages during the last boot attempt.

Now, if you would like to see the messages your kernel produces during boot time, you will have to fire up an editor and edit /etc/default/grub in which you shoudl change a line that reads GRUB_HIDDEN_TIMEOUT_QUIET to false


Does 12.04 support the Dell Perc 6i RAID card?

Yes, the Dell Perc6 series is officially supported by Ubuntu
The Dell Perc 6-series cards are rebranded LSI Megaraid cards with the LSI1078 chipset. The drivers for LSI Megaraid in Ubuntu have been stable for a very long time, and specifically support the Dell 6 series:

The mfi driver supports the following hardware:

     +o   LSI MegaRAID SAS 1078
     +o   LSI MegaRAID SAS 8408E
     +o   LSI MegaRAID SAS 8480E
     +o   LSI MegaRAID SAS 9260
     +o   Dell PERC5
     +o   Dell PERC6
     +o   IBM ServeRAID M5015 SAS/SATA
     +o   IBM ServeRAID-MR10i
     +o   Intel RAID Controller SROMBSAS18E

I have a Megaraid 8408E and Ubuntu Server 12.04 has been working fantastically with it.


After installing ubuntu facing issues while starting windows8.1

I suggest you to try below and check,,, http://www.maketecheasier.com/fix-window-linux-boot-problems-with-super-grub-disk/

www.youtube.com/watch?v=Lkz2Q_F77lM

supergrubdisk (user friendly gui interface) to recover both windows can be used to recover windows bootloader most of the time..

http://www.supergrubdisk.org/wizard-restore-grub-with-super-grub2-disk/

or

www.supergrubdisk.org/wizard-restore-grub-with-rescatux/

and also check this if you cant do it from above..
sourceforge.net/projects/boot-repair-cd/

I have not used boot repair cd by my self, but I just happened to read a comment made by user in sourceforge regarding boot repair cd... "Has worked in a few different scenarios. Fixed boot issues for various versions of Windows and Linux. Impressive. Looking at other reviews, it's a shame there's no version with support for older CPUs. Lets have some new releases please :-) thanks very much"


This package includes the Recommendations produced by the World Wide Web Consortium (W3C) standardization body in HTML format.

To get information about an Ubuntu package, visit this site:
https://packages.ubuntu.com/

w3-recs package information:
https://packages.ubuntu.com/disco/w3-recs

w3-recs files list:
https://packages.ubuntu.com/disco/all/w3-recs/filelist


Error running : apt-get install ttf-mscorefonts-installer

cabextract is in the universe repository, if you update your /etc/apt/sources.list:

#############################################################
################### OFFICIAL UBUNTU REPOS ###################
#############################################################

###### Ubuntu Main Repos
deb http://us.archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse

###### Ubuntu Update Repos
deb http://us.archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://us.archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse

Then run

sudo apt-get update
sudo apt-get -f install

apt will install cabextract to meet the dependencies of the partially installed ttf-mscorefonts-installer. If that doesn't work, try sudo apt-get install ttf-mscorefonts-installer again.


Behavior of powersave freq governor when cpu quota is set

The document referenced in your question 1 is for the acpi-cpufreq CPU frequency scaling driver. I think, but am not certain, you are using the intel_pstate CPU frequency scaling driver. The way to know for sure is to ask your system:

$ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver
intel_pstate
intel_pstate
intel_pstate
intel_pstate
intel_pstate
intel_pstate
intel_pstate
intel_pstate

The powersave governor in the intel_pstate driver behaves similarly to the ondemand governor in the acpi-cpufreq driver. The control algorithms have been changing, but if you have recent enough kernel should be load based.

The CPU frequency does not go up much, or even at all, when you limit use to 50% because the load based algorithm isn't presented with enough load to warrant raising the CPU frequency.


Start up script, mounting and binding depending on if drives are present?

There are multiple issues with your script:

You are chaining (&&) unrelated commands, a failure on one will skip the rest.
You are using "~" in the path name, the script is invoked with root, whicih means it will be translated into /root, you must use the full path name
You don't need to use sudo because it's running with root.

The folllowing script will do what you have requested:

[[ -d /media/Storage/Music ]] &&  mount -o bind /media/Storage/Music /home/your_user/Music
[[ -d /media/storage/downloads ]] && mount -o bind /media/storage/downloads /home/your_user/Downloads
[[ -d /media/2TB/Videos ]] && mount -o bind /media/2TB/Videos /home/your_user/Videos
mount -o bind /home/john/dropbox/documents /home/your_user/Documents
mount -o bind /home/john/dropbox/Photos /home/your_user/Pictures
exit 0


According to the syncevolution doc, the location of the certificates
used to authenticate the server is configurable through 'SSLServerCertificates' configuration property.

This property is set by the 'config.ini' files in the home directory:

phablet@ubuntu-phablet:~$ grep -rIn SSLServerCertificates .config/syncevolution/
.config/syncevolution/default/peers/google-calendar-2/config.ini:# SSLServerCertificates = /etc/ssl/certs/ca-certificates.crt:/etc/pki/tls/certs/ca-bundle.crt:/usr/share/ssl/certs/ca-bundle.crt
.config/syncevolution/default/peers/google-contacts-2/config.ini:# SSLServerCertificates = /etc/ssl/certs/ca-certificates.crt:/etc/pki/tls/certs/ca-bundle.crt:/usr/share/ssl/certs/ca-bundle.crt
.config/syncevolution/google-calendar-2/peers/target-config/config.ini:# SSLServerCertificates = /etc/ssl/certs/ca-certificates.crt:/etc/pki/tls/certs/ca-bundle.crt:/usr/share/ssl/certs/ca-bundle.crt
.config/syncevolution/google-contacts-2/peers/target-config/config.ini:# SSLServerCertificates = /etc/ssl/certs/ca-certificates.crt:/etc/pki/tls/certs/ca-bundle.crt:/usr/share/ssl/certs/ca-bundle.crt

So, you can add or edit these configs to additionally point to some .crt in the home dir (which is writable).


"No WIFI adapter found" on dell precision 5510 with intel wireless 6280 card

No wifi option on Ubuntu (18.04 and 16.04)
i followed the steps on this thread and solved the No wifi Issue.


How can I disable the title bar in Unity on 11.10?

The so called Unity "panel" (the top bar) is supposed to merge with the bar of a maximized window, but the contents of the window's client area are left to the application, i.e. Chrome in this case.

As for your other question, the answer is no. There's no setting to hide or autohide the Unity panel in Ubuntu 11.10 without a GUI app running. I was looking for something like that when I stumbled upon these:

https://bugs.launchpad.net/unity/+bug/579674
https://bugs.launchpad.net/unity/+bug/853865

You can still toggle full screen mode by hitting F11 (that should work with other applications as well), but doing so will also remove the tab captions in Chrome.


How to delete non existing external disk

You missed the second option at the end, i had to do this with the same issue after fdisk did not delete it.

"Other option is to check fstab and see if there is an entry for it, if so remove it"

Re-adding fsdisk steps in case someone else may find it useful

First, get a listing of your current partition scheme, type the following command:
fdisk -l

You Listed you want to remove a partition from /dev/sdb disk. Type the following command:
fdisk /dev/sdb

Now type p command to list partition:
Command (m for help): p

If you see partitions, remove them just to be safe /dev/sdb3 (3rd partition). Type the d command to delete a partition:

Command (m for help): d

Partition number (1-4): 3

It will prompt you for the partition number. Type 3:

Verify that partition deleted:

Command (m for help): p

Now save the changes and exit to shell prompt. Type the w command:
Command (m for help): w

Reboot the system.


Is there an audio player for Ubuntu that can automatically decompress and play gzipped music?

I know of two solutions:

Use DeaDBeeF with the RAR, 7z and Gzip archive reader plugin.
Run foobar2000 through Wine with the Unix Archive Support component.  This is kind of cheating since it's a Windows program, but I do this since foobar2000 is my player of choice.


I've created a working bootable USB stick! Now how do I "finish it"?

There are a few very broad options.

When I boot off the USB stick, I get GRUB menu offering "Try Ubuntu without installing", "Install Ubuntu", "OEM install (for
manufactures)", and "Check disk for defects"

I want this to boot straight into a full Ubuntu Install.

There are 2 options you have here
First - you need to modify the boot menu. There are detailed instructions on how to do so here - How to bypass "Try it / Install" screen when booting from USB Live Session? (without installing in the USB)
Second - Install Ubuntu onto the flash drive - will come back to this.

When I boot into "Try Ubuntu", the drive is very small.

I want to make the full space of my 32GB USB stick available
I don't want to waste my precious little space on tools for installing Ubuntu on another drive. (This is my drive!)

Again you have a few options
First, partition the USB. If you shrink the partition with the live files you can create a second partition and mount it (manually) after you boot. If you wanted to make this permanent you would need to remaster the iso. This is a good option if all you need is data storage.

Note - could be done loop mounting a file as well, but that gets a bit more complicated.

Second, use persistence. This is described in detail in several locations
How do I get a live-USB to use a partition for persistence?
https://help.ubuntu.com/community/mkusb/persistent
https://wiki.ubuntu.com/LiveUsbPendrivePersistent
The disadvantage of this option is that persistence has limitations:

It is a COW system , and thus all your changes are written to a file which is mounted as an overlay. This works all right for minor changes such as installing a few packages or making customization to your interface or saving wifi passwords, but will fail if you instll many packages or try to maintain the system with sudo apt update && sudo apt upgrade as there is not method to track all those changes.

Your third option is to do an install into the usb itself (will come back to this).

The drive seems to be in a Guest/Read-only-ish mode.

I tried to remove the media files in the Examples directory linked on the Desktop and got an error
I tried to downloaded the [google-chrome-stable deb from Google][2], but...

the Ubuntu GUI installer doesn't even seem to try to open it.
dpkg -i won't install it because of 3 dependencies.
apt can't locate any of the 3 dependencies.
none of the answers on How to install Google Chrome
work for me.

Well there are several problems here, I will not address the problem with google chrome, that is a separate issue.
But yes, when you boot the .iso the file system is squashfs , and this file system is ro. You can only make changes to the system (delete files, edit config files) by remastering the iso.
See https://help.ubuntu.com/community/LiveCDCustomization
Short of remastering there is no way to make those sorts of changes. If you try to do so with persistence you are highly likely to either have the same error or eventually you will break persistence as the COW method of persistence is not designed to make changes to the ro squashfs system.

My suggestion:
With what you are wanting to do, IMO, the best solution is to do a regular install into the flash drive, it will then act as a normal install, and you can install, upgrade, and customize all you want.
A full install should be just as portable / flexible as the live media.

Where to go from here
Your question is actually quite broad. Pick one of the options (persistence, remaster the iso, or install) and post if you have a specific problem.
As far as chrome, the answer you linked should work. If it does not you may need to file a bug report with chrome as it is a 3rd party app.
Alternates to chrome include chromium (same browser without the branding). You would file a bug report, if needed, with Ubuntu.
Or Firefox. Firefox is on the verge of a new release and it looks good.
https://blog.mozilla.org/blog/2017/09/26/firefox-quantum-beta-developer-edition/
It is the firefox daily ppa https://launchpad.net/~ubuntu-mozilla-daily/+archive/ubuntu/ppa and will likely be available in the ubuntu repositories very soon.
See How to replace downloaded binary file with one downloaded from software manager?


How could I begin C++ programming on Ubuntu?

You have the standard gcc that comes with Ubuntu. Just ALT+F2 and type gnome-terminal or press CTRL+ALT+T to start a console.

To start programming in the console, just type nano test.c; that way you start working on your first test.c file. Try this:

#include <stdio.h>
int main ()
{
printf("Hello AskUbuntu!");
}

then just press CTRL+X and press Y, then ENTER to save and close.

Compile this test.c file using gcc by typing: gcc test.c -o mytest, which will create a file called mytest (which is executable by typing ./mytest) using the code from test.c.

The same can be said for C++ code. It works the same way as gcc: Compiling a test.cpp file using g++ by typing: g++ test.cpp -o mytest, which will create a file called mytest (which is executable by typing ./mytest) using the code from test.cpp.

This is one way.

Another way I recommend is using Code::Blocks which has been known to work since I have tested it (Ubuntu 8.04, 8.10, 9.04, 9.10, 10.04 and 10.10). Works right out the box, no errors, no nothing. The one I have used so far was Code::Blocks 8.02 but 10.05 came out a couple of months ago and it looks good.

You can install it by running sudo apt-get install codeblocks.

The last method I recommend is Aptana, which is a complete GUI IDE system. Aptana is very complex and will certainly resolve any doubt you have with its complete help system and autocomplete, autohelp way of working. Aptana is much better than the IDE from Microsoft let me tell you right now. Already worked on both for some time now and I will not leave Aptana for big works.

I will leave here some links so you can test:

APTANA - http://www.aptana.com/
CODEBLOCKS - http://www.codeblocks.org/
New Version of C - http://en.wikipedia.org/wiki/C1X
New Version of C++ - http://en.wikipedia.org/wiki/C%2B%2B0x


Apache subdomain redirects to main domain

OK .. finally figured out the issues.. got it to work

first of all on your host dns ... you need to add the record for your server name
I use namecheap.com  .. I added a A + Dynamic DNS Record with a host john and my ip address ... same as my A record for www ... I'm assuming its just a standard A Record anywhere else

once that was there .. it may take a while before you can actually ping it once you can .. you will be good to go if all your other settings were correct

Ok now for the configuration files i used.. I created two in sites-available..

the first one was called 001-john.conf I found out that it is important to have the file end in .conf or you wont be able  to use a command  that seemed to fix the issue.

In that configuration I added the following :

<VirtualHost *:80>
    ServerAdmin webmaster@mysite.com (of course you would use your domain name instead of mysite.com)
    ServerName john.mysite.com
    ServerAlias john.mysite.com
    DocumentRoot /web/john (of course you would make the root the path to the folder where the files are stored)

<Directory />
    Options FollowSymLinks ExecCGI
    AllowOverride ALL
</Directory>
<Directory /web/john/>
            Options ExecCGI FollowSymLinks Includes Indexes (or whatever directives you want)
            AllowOverride ALL
            order allow,deny
            allow from all
</Directory>

ScriptAlias /cgi-bin/ /web/plus/cgi-bin/  (if you wanted to create a cgi bin use your correct path for this)
<Directory "/web/plus/cgi-bin">
    AllowOverride ALL
    Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
    Order allow,deny
    Allow from all
</Directory>
ErrorLog /var/log/apache2/errorjohn.log
CustomLog /var/log/apache2/accessjohn.log combined
</VirtualHost>

the second configuration file was for ssl and i called it 001-john-ssl.conf
It looked like this:

<IfModule mod_ssl.c>
<VirtualHost *:443>
        ServerAdmin webmaster@mysite.com
        ServerName john.mysite.com
        ServerAlias john.mysite.com
        DocumentRoot /web/john

<Directory />
    Options FollowSymLinks
    AllowOverride ALL
</Directory>

<Directory /web/john/>
    Options Indexes FollowSymLinks Includes MultiViews ExecCGI
    AllowOverride ALL
            Require all granted
</Directory>

ScriptAlias /cgi-bin/ /web/plus/cgi-bin/
<Directory "/web/plus/cgi-bin">
    AllowOverride ALL
    Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
    Order allow,deny
    Allow from all
</Directory>

    LogLevel warn
    ErrorLog /var/log/apache2/errorjohn.log
    CustomLog /var/log/apache2/accessjohn.log combined

   SSLEngine on
   SSLProtocol all -SSLv2
   SSLCipherSuite ALL:!ADH:!EXPORT:!SSLv2:RC4+RSA:+HIGH:+MEDIUM
   SSLCertificateFile    /etc/apache2/ssl/your.crt file
   SSLCertificateKeyFile /etc/apache2/ssl/your.key file
   SSLCACertificateFile /etc/apache2/ssl/your.ca-bundle
   SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown
</VirtualHost>
</IfModule>

once that was all saved I ran

sudo a2ensite 001-john.conf

and

sudo a2ensite 001-john-ssl.conf

Then I ran

sudo service apache2 reload

Then to check to see if it had both .. which before it didnt before .. I just created links from site-available to site-enabled .. that didnt seem to work for me but after running a2ensite with the files labeled with the .conf extention..I ran apachectl -t -D DUMP_VHOSTS and had this result:

VirtualHost configuration:
*:443                  is a NameVirtualHost
         default server mysite.com (/etc/apache2/sites-enabled/000-default-ssl.conf:2)
         port 443 namevhost mysite.com (/etc/apache2/sites-enabled/000-default-ssl.conf:2)
         port 443 namevhost john.mysite.com (/etc/apache2/sites-enabled/001-john-ssl.conf:2)
                 alias john.mysite.com
*:80                   is a NameVirtualHost
         default server mysite.com (/etc/apache2/sites-enabled/000-default.conf:1)
         port 80 namevhost mysite.com (/etc/apache2/sites-enabled/000-default.conf:1)
         port 80 namevhost john.mysite.com (/etc/apache2/sites-enabled/001-john.conf:1)
             alias john.mysite.com

**just as a note .. my original site is located in directory /web/public and the subdomain site is located at /web/john... since yours was located at /var/www/html I would probably use something like /var/www/forum for you subdomain folder to store your forum files in  and i would use forum.yoursite.com as the ServerName and ServerAlias but hopefully with the example you will see the format and setup of everything.

once the dns records got updated from namecheap .. i was able to access john.mysite.com and it would show the simple "under construction" file in there and if i just went to www.mysite.com it would give me my normal page that was setup a while ago

so now its working with a subdomain

Hopefully this will help you through and set things up properly .. most likely its because the configuration files probably didnt have the .conf extensions and you didnt use a2ensite to enable them.. that seemed to be the problem i was running into


Your path should be PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/usr/lib/jvm/jdk1.7.0_51/bin"

not

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games/usr/lib/jvm/jdk1.7.0_51/bin".

You are missing : beetween /usr/local/games and /usr/lib/jvm/jdk1.7.0_51/bin


HP Officejet Pro X 451dw doesn't work with Focal Fossa, though it did with Bionic Beaver

Yesterday I have finally discarded Xubuntu and installed Linuxmint. I am very happy with the decision. Printing worked at once, the documentation and instructions are much more detailed, a higher emphasis on security and the best of all:
The LTS - Version I have installed will be supported until April 2025! A stable system for 4 years, thank goodness!


.exe file created by C programming through gcc compiler isn't executing

I solved the problem. I followed the following website.

http://www.sinarpelangi.com/how-to-set-executable-permission-at-ntfs-partition-on-linux/

I ran the following commands:

sudo blkid -c /dev/null (It will list all the partitions we have. In my computer, it displays,)
sudo umount /media/partitionname
sudo mkdir /media/partitionname
sudo mount /dev/sdaX -t ntfs-3g -o uid=1000,gid=1000,umask=002 /media/partitionname

where partitionname is the name of your NTFS partition and in sdaX, X is number obtained from the first command i.e. sudo blkid -c /dev/null.

Now I can write C program, can execute in the same partition (in NTFS). Without these commands, the file color was white when the command ls -al is used. But now the color has changed to green after listing it through ls -al command.


How do I fix this error? Error: Opening the cache

Open a Terminal with CTRL+ALT+T and type:

sudo mv /etc/apt/sources.list.d/opera.list /etc/apt/sources.list.d/opera.list.disabled
sudo apt-get update


from XFCE Getting Started Guide

  Stick / unstick windows

  If you “stick” a window, it will be visible at the same place on all
  your workspaces. The same repeated action make a window to
  stick/unstick :

  click the stick/unstick button of the title bar open the window menu
  button from the title bar and choose “Stick” or “Unstick” item use the
  Alt + F10 keyboard shortcut


You might find rvm helpful. Rvm is a command line program that allows you to manage multiple versions of ruby. If you are interested, you can read more about it here.

If you just want to get rid of Ruby 1.8.1, run the following command:
sudo apt-get remove ruby1.8


how to remove Ubuntu and leave Windows 7 and Linux Mint

To remove Ubuntu (and/or any other Operating System), you can use this little tool: OS-Uninstaller.


Try
sudo nvidia-xconfig -sli = on -multigpu = on
Or
sudo nvidia-xconfig -sli = auto -multigpu = auto


Is is safe to remove all of *-doc packages?

It depends upon the package. Packagers decide if -doc packages are required, merely recommended, or neither.

-doc packages are not usually the manpage. -doc packages usually include extra documentation, often including helpful examples and/or tutorials.

You can ask apt to remove -doc packages, but READ CAREFULLY apt's offer in response to ensure you are not agreeing to remove much more than you wanted. Alternately, use apt's --simulate flag to test a removal before executing for real.

There are a couple system utilities for handling documentation: doc-base and docbook-xml. We strongly recommend that you leave those in place on your system, unless you really know what you are doing.

Most -doc packages are recommended, not required. During an install, you can use, apt's --no-install-recommends flag to install only required (not recommended) dependencies. HOWEVER, some features of your new software may require other recommended packages, so this is a bit of a blunt tool.

Most users should not need to remove -doc packages, nor care about 'required' vs 'recommended' packages. The whole point of Ubuntu is that the defaults are set to meet the needs of most users without any additional tweaking. -doc packages are generally inert, and the amount of space they use is very, very small.


How can I troubleshoot my system freezing just before restart?

this guy has similar problem and he seems to found the reason and solve it.

hope it will work for you too.


Switching between active RDP's via Reminna (How-To)

Just a quick update. After searching through few source I figured it out for my self. It looks bit idiotic for me as I didn't notice (since I was using a full screen) that there's a screen toggle option to switch in between (seen below).

Also, what I found is shortcut key which make it more easier not click on the toggle icon.

Hold Right CTRL + < / > (left/right arrow keys) to switch between active screens.

Hope this helps!


firewall ufw is "enable and active" but gufw is off

It does not matter if you enable or disable the firewall in the terminal, since the *gufw app needs administrative rights it will always open like this:

after you unlock the app with your password then you will see that it is actually active:

This is because the system does not know if the person opening gufw is the same person that enabled the Firewall in the terminal (You might have just walked out of the room to go to the bathroom and a hacker just climbed through the window, ran to your computer and tried to open gufw while you were away). So this is why it asks again, just to make sure.


alias burp="java -jar -server -Xms1048m -Xmx2G -XX:-DisableExplicitGC -XX:+UseT$

The alias "burp" does not have a closing quote mark at the end. So the all aliases below this line in your RC file will throw this error.


How to Compress (More than one at a time) PDF files from terminal

You can use the same command or mogrify as you've said, just by adding a bit of bash.

find $HOME/PDF_Lib -iname '*.pdf' | while read pdf; do ps2pdf -dPDFSETTINGS=/ebook "$pdf" "${pdf:0:(-4)}_new.pdf"; done

OR

find $HOME/PDF_Lib -iname '*.pdf' | while read pdf; do mogrify -resample 150 -compress JPEG -quality 80 "$pdf"; done


shader3 not enabled error in Eve Online Crucible

The following steps were mentioned in a forum post at EvE Online:

You should have wine and msttcorefonts installed.
Download the client software for Microsoft Windows
Open the file $HOME/.wine/user.reg (directory .wine in your personal directory. The filename is user.reg)

Add the following content:

[Software\\Wine\\Direct3D]
"DirectDrawRenderer"="opengl"
"OffscreenRenderingMode"="fbo"
"PixelShaderMode"="enabled"
"VertexShaderMode"="hardware"

Now the software should work as expected.


Package management system corrupted. Cannot install or remove packages. U12.04LTS

Try the steps provided in this answer.  It always works for me.  If it fails, it would be valuable to learn why and add to it:

https://askubuntu.com/questions/461975/i-cant-edit-update-remove-or-install-my-broken-packages

$ sudo apt-get autoremove
$ sudo apt-get --purge remove && sudo apt-get autoclean
$ sudo apt-get -f install
$ sudo apt-get update
$ sudo apt-get upgrade && sudo apt-get dist-upgrade
$ sudo dpkg-reconfigure -a
$ sudo dpkg --configure -a

You performed most of them.  There are still a couple more that can be added.  But so far the ones in the list has fixed my corrupted Ubuntu broken package problems.


Regarding the reason why you are now unable to log in, that is most likely due to the edit you made to ~/.profile; your login shell is trying to execute an invalid command (because the NVM install failed) and quitting. To repair this, you will need to undo that edit to your ~/.profile somehow. The easiest way is probably to hold shift during a reboot, select Recovery Mode from the menu, drop to a root shell prompt, then edit the file and reboot again.

As for why the original command failed, I would guess that your system doesn't have git installed (the github page says "(requires Git)"). Once your system is back in working order, try this before attempting to install NVM again:

sudo apt-get install git


Is there a way to grep the gnome-terminals history?

The output is not stored in any files, no. But you can use the script command to record a terminal session. Just run

script

Then run your commands as usual. When you type exit, you will exit the script program. All input and output can then be found in a file named typescript in your current directory. You can use less -R typescript to read and search through it.

As usual, it's a good idea to read the manual before using a new command. man script


How to fix hash sum mismatch error on fresh docker image update?

The chosen solution didn't work for me. And I noticed that this isn't always the case - that is, if I wait a day or two, I don't get the error. I suspect it has more to do with the ubuntu repositories than the version of docker we use (as explained by Robie).

My solution is to use one of the official mirrors instead of the default ubuntu repo. Replace xenial with your ubuntu version. You might need an extra deb-src line for all or none of the lines depending on where you are getting the mismatch. I noticed that the mirrors are slower compared to the default.

RUN rm -rf /etc/apt/sources.list
RUN echo "deb mirror://mirrors.ubuntu.com/mirrors.txt xenial main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-updates main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb-src mirror://mirrors.ubuntu.com/mirrors.txt xenial-updates main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-backports main restricted universe multiverse" >> /etc/apt/sources.list
RUN echo "deb mirror://mirrors.ubuntu.com/mirrors.txt xenial-security main restricted universe multiverse" >> /etc/apt/sources.list


Ubuntu 13.04 Wifi is connected but doesn't work after a while

check ifconfig output when you dont have connection. Then if you see wlan0 interface and ip address on it try to ping your gateway. If you cant - see the otput of arp -n. If there is no record for your gateway ip address then try to reestablish wireless connection. Repeat all this if you dont have connection. If it is the same try with another router or change the configuration of your router - wireless mode b/g/n , channel number etc.. if the problem persists try changing your router.


18.04 LTS new install -- No desktop after login

A few of the possibilities:

Boot into your system BIOS and disable the on-board graphics chip-set if  you have installed a discrete graphics card.
If this does not help. Boot into Recovery mode Check file system (fsck)

If this also does not help. Boot into Recovery mode, drop to root terminal & Command:

apt update
apt upgrade
apt install --reinstall lightdm
dpkg-reconfigure lightdm

and select lightdm

and maybe

apt install --reinstall ubuntu-desktop

and reboot


You do not have permission to extract to this folder

Most software shouldn't be installed this way.
First you should make sure /opt is really where you want to put it, and that you really want to install the file from that archive at all, rather than another source.
/opt is usually used for software that is not part of Ubuntu and not installed using Ubuntu's package manager (since when it is, it usually goes in multiple subdirectories of /usr.). In addition, most often it's used for software that is provided as pre-built binaries, and not software that you're building from source code (since that usually goes in multiple subdirectories of /usr/local).
A lot of software that is available as pre-built binaries is also packaged officially for Ubuntu (see also this question), is packaged in an unofficial PPA, or is provided in a downloadable .deb file. Those methods are often preferable (usually in that order) to installing unpackaged pre-built binaries.
If you're sure you want to unpack the archive to /opt...
If you know you want to install software in /opt, you should check if there are official guidelines, specific to that application, for how best to do so. The developer or vendor of the software may have specific recommendations that cover installation issues beyond how and where to unpack the files.
With all that said, if you know you want to extract it in /opt, you can do this in the Terminal (Ctrl+Alt+T) by running:
cd /opt
sudo cp /path/to/filename.tar.gz .
sudo tar xf filename.tar.gz
You would replace the italicized /path/to/filename.tar.gz with the actual location and filename of the file you want to put in /opt and extract. Dragging a file from Nautilus (the file browser) into the Terminal application will automatically paste its full path on the current line, which can make things easier.
If you feel you must use the Archive Manager to extract the file...
If you want to extract the software with the Archive Manager, you'll have to run the Archive Manager as root, just as the cp and tar commands in the above example were run as root. It's widely recommended to avoid running graphical programs as root unless you really know you want to--often they are not designed or tested with such use in mind.
If you really do want to run the Archive Manager as root, you can do so by pressing Alt+F2, typing the command gksudo file-roller and pressing Enter. You should be very careful after doing this -- for example, you can access and overwrite important system files. You should make sure to close the program when you're done so you don't later forget that it's running as root (rather than as your user) and use it for something else where it's not needed.

If you're using Ubuntu MATE, run engrampa instead of file-roller.
If you find you don't have the gksudo command, you can get it by installing the gksu package in the Software Center. (Or you can use one of the other ways to run graphical applications as root.)
Of course, you can avoid all this complexity by unpacking archives with sudo tar... in the Terminal (see above) when you need to do as as root, and reserving the Archive Manager for the more typical cases when you want to extract an archive without elevated privileges.

I don't recommend doing it this way, and this section is provided mainly for completeness or in case you're sure you want to run the Archive Manager as root. You do not need to run the Archive Manager as root to install software, even if you choose to install it from a .tar.gz archive file and choose to put it in /opt.
General information about manual installation from downloaded archives:
Often it's better to install software through the other ways listed, with links to guides, in the first section of this post. However, if you are going to install software by unpacking a .tar.gz (or similar) archive, I recommend you read How do I install a .tar.gz (or .tar.bz2) file? before proceeding.


I'm guessing you're drawing this idea from Microsoft's ReadyBoost implementation in the Windows line.

ReadyBoost works in conjunction with SuperFetch. SuperFetch, also introduced in Windows Vista, monitors the programs you use on your computer and automatically loads their application files and libraries into your computer’s memory (RAM) ahead of time. When you launch the application, it will start faster — your computer reads its files from memory, which is faster, instead of from disk, which is slower. Empty RAM doesn’t do any good, so using it as a cache for frequently accessed applications can increase your computer’s responsiveness.
SuperFetch normally uses your computer’s memory – it caches these files in your RAM. However, SuperFetch can also work with a USB stick – that’s ReadyBoost in action. When you connect a USB drive to your computer and enable ReadyBoost, Windows will store SuperFetch data on your USB drive, freeing up system memory. It’s faster to read various small files from your USB stick than it is to read them from your hard drive, so this can theoretically improve your system’s performance.

HTG Explains: Is ReadyBoost Worth Using?
If you were to treat your flash drive as RAM, your computer would be depending on it as though it had the same access speeds as RAM. This introduces the possibility of your computer actually waiting for data to be read/written to/from this "RAM" before moving on and performing the next task. As you should be able to tell, this may actually end up slowing your computer down rather than speeding it up.
While it would be a very interesting experiment, it's probably not what you're looking for. You'd be better off adding more RAM, but only if the RAM is the culprit of the problem. Perhaps perform some testing before going out and spending money on it.


I'm a noob at Linux, but try pressing the super (usually a Windows logo) key, then type docker and press enter (You have probably already tried that though)


Ubuntu 17.10 No external connections outside of localhost

General troubleshooting of networking stack as follows:

First of all check on your service is running and listening on network socket (interface) i.e ipaddress and port number. By running the following:

netstat -lanp | grep apache2

Note the ip address and port number from above command.In my case that's

tcp6       0      0 :::80               :::*              LISTEN      12253/apache2
tcp6       0      0 :::443              :::*              LISTEN      12253/apache2

Try to telnet on into your socket from another machine

telnet ipaddress_ofyour_apache_host 80

you should get

Trying ipaddress_ofyour_apache_host..
Connected to ipaddress_ofyour_apache_host

If you get connected that's meaning that on os network level is everything working fine no firewall is blocking or other issues
If you still don't get a welcome page from apache go ahead and check apparmor and for purpose of checking disable it temporarily

sudo systemctl stop apparmor.service
sudo update-rc.d -f apparmor remove

Check again from your web browser if you still don't get a page go ahead and check apache2 access.log


Problems accessing a Cisco Router from Ubuntu 18.04 via SSH

Thanks,

The issue was on the /etc/ssh/ssh_config file as ciphers are disabled by default on Ubuntu 18.04. Once I removed the comment sigh (#) I could login the router with no problem.


Dual OS backup Windows and Linux, including filesharing

If you have a ton of files, be them music files, videos, raw data or if you are just looking to expand your hard drive space for the heck of it… you simply can not go wrong with the MyBook line of products.

I now have over 3 terabytes worth of storage at my beckoning call and I could not be happier. Invest in a MyBook and you will be happy you did.

Look at the USB 3 model it will also work with USB 2 with the pigtail adapter. The 7200 RPM drive is also very fast. Comes plug n play for Windows.


As suggested by DevRobot you can look at the output of ifconfig or ip addr to find the current ip address of eth0.

This will work only if eth0 exists and only if it has currently got an ip address.

if eth0 exists but you can not see an IP address then first check that your ethernet is connected, the output of ip addr should show state UP.

Then presuming that your network has a standard home router, you expect to get your ip address over DHCP, which is most likely, then you can try the following command:

sudo dhclient eth0

Then check your ip with the command ip addr again.

If the dhclient command worked, then this indicates a probable issue with your configuration, I recommend posting your /etc/network/interfaces file so we can check it.


Ubuntu 12.04 comes with a OpenSSL 1.0.1, which has somewhat different defaults than the older OpenSSL 0.9.8 version.

Among other things, if you're using openssl req -newkey rsa:2048 to generate an RSA key, you'll end up with a key in a format called PKCS #8.  Represented in the PEM format, these keys have the more generic -----BEGIN PRIVATE KEY----- header, which doesn't tell you what kind (RSA, DSA, EC) key it is.

Previously, with OpenSSL 0.9.8, keys were always in a format called PKCS #1, which represented as PEM, had the header -----BEGIN RSA PRIVATE KEY-----.

Because of this you cannot simply change the header and footer from:

-----BEGIN PRIVATE KEY-----

to

-----BEGIN RSA PRIVATE KEY-----`

It's not the same thing and it won't work.  Instead you need to convert the key to the old format using openssl rsa.  Like this:

openssl rsa -in key_in_pkcs1_or_pkcs8.pem -out key_in_pkcs1.pem

MySQL (v5.5.35) on Ubuntu 12.04 is using an SSL implementation called yaSSL (v2.2.2).  It expect keys to be in the PKCS #1 format and doesn't support the PKCS #8 format used by OpenSSL 1.0 and newer.  If you simply change the header and footer, as suggested by other posts in this thread, MySQL/yaSSL won't complain, but you'll be unable to connect and instead end up with an error like this:

ERROR 2026 (HY000): SSL connection error: protocol version mismatch

Ubuntu 14.04 comes with OpenSSL 1.0.1f and new settings.  Among other things, it will generate certificates with SHA256 digests instead of SHA1, which was used in earlier versions.  Incidentially, the yaSSL version bundled with MySQL doesn't support this either.

If you're generating certificates for use with MySQL, remember to make sure the RSA keys are converted to the traditional PKCS #1 PEM format and that certificates are using SHA1 digests.

Here's an example of how to generate your own CA, a server certificate and a client certificate.

# Generate a CA key and certificate with SHA1 digest
openssl genrsa 2048 > ca-key.pem
openssl req -sha1 -new -x509 -nodes -days 3650 -key ca-key.pem > ca-cert.pem

# Create server key and certficate with SHA1 digest, sign it and convert
# the RSA key from PKCS #8 (OpenSSL 1.0 and newer) to the old PKCS #1 format
openssl req -sha1 -newkey rsa:2048 -days 730 -nodes -keyout server-key.pem > server-req.pem
openssl x509 -sha1 -req -in server-req.pem -days 730  -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 > server-cert.pem
openssl rsa -in server-key.pem -out server-key.pem

# Create client key and certificate with SHA digest, sign it and convert
# the RSA key from PKCS #8 (OpenSSL 1.0 and newer) to the old PKCS #1 format
openssl req -sha1 -newkey rsa:2048 -days 730 -nodes -keyout client-key.pem > client-req.pem
openssl x509 -sha1 -req -in client-req.pem -days 730 -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 > client-cert.pem
openssl rsa -in client-key.pem -out client-key.pem


Should i update ubuntu 12.04 iso image to 14.04 iso image using zsync?

That's not a good idea. It's better to wait until tomorrow April 17 and download the Ubuntu 14.04 final release (update: Ubuntu 14.04 final release is now available for download). By the time you figure out how to update your Ubuntu 12.04 iso and make it work as an Ubuntu 14.04 iso, it will probably be April 17 anyway, and you will be able to download the final release of Ubuntu 14.04.


A more recent workaround that works for more Linux operating systems than the DBUS_SESSION one:

dropbox stop && dbus-launch dropbox start

EDIT: To make this permanent see answer by @juankvillegas below.


Where the desktop is is defined in ~/.config/user-dirs.dirs. If you want to place icons on the desktop, you have to create *.desktop files and put them into the folder [whatever comes after XDG_DESKTOP_DIR=].

*.desktop files are structured like this:

#!/usr/bin/env xdg-open
[Desktop Entry]
Version=1.0
Terminal=false
Type=Application
Name=C++ Eclipse
Exec="/home/christoph/.IDEs/C++ Eclipse/eclipse"
Icon=/home/christoph/.IDEs/C++ Eclipse/icon.xpm
Keywords=eclipse;c++;programming;developing;code;coding

You can find other examples (probably with a lot more content) in /usr/share/applications. The address for trash is trash:///, so Exec could be Exec="nautilus trash:///".


Prevent SyncTeX from opening new instance Evince?

I figured out how to solve this. The problem was that the instance started by Synctex wasn't recognized by the command in my 'External Tools' script.

The Synctex instance was listed as /usr/bin/evince file:///path/to/my/file.pdf, whereas the instance called by xdg-open was listed as evince file.pdf.

So, I just changed my script such that it will also be listed as /usr/bin/evince file:///path/to/my/file.pdf. My External Tools script now reads:

#!/bin/bash

if [ "$GEDIT_CURRENT_DOCUMENT_TYPE" == "text/html" ]; then

    google-chrome $GEDIT_CURRENT_DOCUMENT_NAME

elif [ "$GEDIT_CURRENT_DOCUMENT_TYPE" == "text/x-tex" ]; then

    filename=$GEDIT_CURRENT_DOCUMENT_NAME
    shortname=`echo $filename | sed 's/\(.*\)\.tex$/\1/'`

    path=file://$GEDIT_CURRENT_DOCUMENT_PATH
    shortpath=`echo $path | sed 's/\(.*\)\.tex$/\1/'`

    latex -synctex=1 -interaction batchmode -src $filename
    dvips -t a4 $shortname.dvi
    ps2pdf -sPAPERSIZE=a4 -dOptimize=true -dEmbedAllFonts=true $shortname.ps
    rm --interactive=never $shortname.dvi $shortname.out $shortname.ps $shortname.blg $shortname.toc $shortname.log
    #xdg-open $shortname.pdf
    /usr/bin/evince $shortpath.pdf

else

    echo "I don't know how to compile files of the type:" "$GEDIT_CURRENT_DOCUMENT_TYPE"

fi


Enabling gigabit ethernet on RTL8111/8168/8411

You can check the capability of your ethernet hardware quite easily. E.g., To check the ethernet hardware device eth0

sudo ethtool eth0
Settings for eth0
    Supported ports: [ TP MII ]
    Supported link modes:   10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Half 1000baseT/Full
    Supported pause frame use: No
    Supports auto-negotiation: Yes
    Supported FEC modes: Not reported
    Advertised link modes:  10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Full
    Advertised pause frame use: Symmetric Receive-only
    Advertised auto-negotiation: Yes
    Advertised FEC modes: Not reported
    Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                         100baseT/Half 100baseT/Full
                                         1000baseT/Full
    Link partner advertised pause frame use: Symmetric
    Link partner advertised auto-negotiation: Yes
    Link partner advertised FEC modes: Not reported
    Speed: 1000Mb/s
    Duplex: Full
    Port: MII
    PHYAD: 32
    Transceiver: internal
    Auto-negotiation: on
    Supports Wake-on: pumbg
    Wake-on: g
    Current message level: 0x00007fff (32767)
                   drv probe link timer ifdown ifup rx_err tx_err tx_queued intr tx_done rx_status pktdata hw wol
    Link detected: yes

Once you established that your hardware and linux driver do support the gigabit speed, you can proceed to check the cable you use and the switch or router you are connecting to.

To force 1000mb full duplex, for enp4s0 try

sudo ethtool -s enp4s0 speed 1000 duplex full

This may or may not work. It may work if your cable is marginal capable of doing 1000mb. Even if this work, you should get a better cable to ensure reliable gigabit connection, otherwise it may renegotiate down to a low speed when errors occur.


You've misinterpreted the output from the command.

It already gave you the recommended package for installation based on your language settings and the most likely package in the category of packages you're seeing in the "Recommends:" lines, aspell-en, which is the English dictionaries.  The system very likely isn't going to install all the dictionaries for all the different languages that aspell supports (which wouldn't make sense anyways, since you probably won't use them).

However...

If you want some of the other languages supported, you will probably have to install them individually, such as if you wanted en (English) and es (Spanish) then: sudo apt-get install aspell-en aspell-es  (this will install aspell-en if it's not installed, and also install the Spanish dictionaries in aspell-es)

If you want all the others, you may have to install them all with one massive command like this (Note that this command as it currently stands is not tested and may trigger conflicts. I'm also not sure why you'd want all the dictionaries for all the different languages, since it's insane to want to be installing all of the languages you aren't going to use):

sudo apt-get install aspell-ca \
    aspell-am \
    aspell-ar \
    aspell-ar-large \
    aspell-bg \
    aspell-br \
    aspell-cs \
    aspell-cy \
    aspell-de \
    aspell-de-alt \
    aspell-el \
    aspell-en \
    aspell-eo \
    aspell-eo-cx7 \
    aspell-es \
    aspell-et \
    aspell-eu-es \
    aspell-fa \
    aspell-fo \
    aspell-fr \
    aspell-ga \
    aspell-gl-minimos \
    aspell-he \
    aspell-hr \
    aspell-hsb \
    aspell-hu \
    aspell-hy \
    aspell-id \
    aspell-is \
    aspell-it \
    aspell-kk \
    aspell-ku \
    aspell-lt \
    aspell-lv \
    aspell-nl \
    aspell-pl \
    aspell-pt-br \
    aspell-pt-pt \
    aspell-ro \
    aspell-ru \
    aspell-sk \
    aspell-sl \
    aspell-sv \
    aspell-tl \
    aspell-uk \
    aspell-uz \
    aspell-da \
    aspell-no


How to stop this command from exit-ing the terminal

time { . ../configure \

You're sourcing configure! Every command in it is then run in the current shell, instead of a subshell. If exit is encountered, the shell will exit. Did you mean:

time { ../configure \


In some cases, the module acer-wmi doesn't correctly translate key presses to action; that is,turn on the wireless. Try removing it:

sudo modprobe -r acer-wmi
sudo rfkill unblock all
rfkill list all

If this works, blacklist acer-wmi:

sudo -i
echo "blacklist acer-wmi"  >>  /etc/modprobe.d/blacklist.conf
gedit /etc/rc.local

The text editor gedit will open the rc.local file. Right above exit 0 add a new line:

rfkill unblock all

Proofread, save and close gedit. Now exit your sudo session:

exit

Reboot and tell us if it's working as expected.


sudo killall -9 dpkg
sudo rm -f /var/lib/dpkg/lock
sudo apt-get -f install
And if you have not a scanner configured said y to the question.
If you have a scanner keep current file.
BR


How to share ubuntu laptop ethernet to android 4.2.2 via usb?

I also want an answer for this question about how to share PC internet via USB and searched on various forums, but get only one answer: "You can share your PC Internet with other device via creating a WI-FI hotspot"

Please go through these reference links:

How to set up a wi-fi hotspot with an Ubuntu laptop (access point mode)?
Create WiFi hotspot on ubuntu
How to create a WiFi hotspot for Android/Windows in Ubuntu
How to Connect & Share your Internet Connection (Wired & Wireless)


Program to Hide/show Given window with hotkey?

The magic search phrase is "quake-like terminal".  More specifically, I searched for "arbitrary quake-like terminal gnome" and the top several hits demonstrate several ways of doing it.  (They claim to be specific to Terminator and gnome-terminal respectively, but in fact can be adapted to any terminal program, or indeed almost any program you choose.)  The first method requires Compiz.


Setting up VPN connection to SonicWall in Ubuntu 18.04

According to the following page, Diffie Hellman Group 2 is modp1024 :

https://wiki.strongswan.org/projects/strongswan/wiki/IKEv1CipherSuites

So the ike (phase 1) and esp  (phase 2) lines should be :

ike=3des-sha1-modp1024!
esp=3des-sha1!

You might find it easier to use the network-manager-l2tp VPN GUI client which uses strongswan and xl2tpd to do L2TP/IPsec connections. Unfortunately the version of network-manager-l2tp in the Ubuntu repository won't support the @123456789 Gateway ID, so will need to build from source.

To build from source:

Prerequisites packages (note : you can safely copy and paste the \ shell line continuation character) :

sudo apt install \
build-essential \
git \
intltool \
libtool \
network-manager-dev \
libnm-util-dev \
libnm-glib-dev \
libnm-glib-vpn-dev \
libnm-gtk-dev \
libnm-dev \
libnma-dev \
ppp-dev \
libdbus-glib-1-dev \
libsecret-1-dev \
libgtk-3-dev \
libglib2.0-dev \
xl2tpd \
strongswan

Obtain the source code :

git clone https://github.com/nm-l2tp/network-manager-l2tp.git
cd network-manager-l2tp
git checkout nm-1-2

Configure :

./autogen.sh
./configure \
  --disable-static --prefix=/usr \
  --sysconfdir=/etc --libdir=/usr/lib/x86_64-linux-gnu \
  --libexecdir=/usr/lib/NetworkManager \
  --localstatedir=/var \
  --with-pppd-plugin-dir=/usr/lib/pppd/2.4.7

Building and installation:

make
sudo make install

You will need to logout of your desktop environment (or reboot) for gnome-shell to properly pickup the installed plugin.

In the nework-manager-l2tp IPsec Options dialog box, enable IPsec and use the following options:

Gateway ID : @123456789
Phase 1 Algorithms : 3des-sha1-modp1024!
Phase 2 Algorithms : 3des-sha1!

the other options should be fairly obvious.

If you do use network-manager-l2tp, you might need to stop the system xl2tpd service, see "Issue with not stopping system xl2tpd service" :

https://github.com/nm-l2tp/network-manager-l2tp/tree/nm-1-2


Well I had the same problem but what I did to remedy the situation was to change the configuration of the vpn to only use the VPN for the resources on the VPN and that will allow you to browse through the normal route and access you synology on the vpn, hope that helps!


How change what  kernel boots Ubuntu  XEN VPS?

Congratulations, you're on PyGrub!

Your menu.lst file, the different kernel images in your /boot directory and most importantly, the kernel you're running (an Amazon EC2 version extremely unlikely to be running on a physical host) strongly imply you do have pygrub enabled.

This is because non-Pygrub XenPVs must use the same kernel as the host

The oddly empty dmesg is likely a side-effect of the customizations in the EC2 kernel; compare with the very informative output of a normal kernel on a XenPV 3.4

A little bit on XenPV kernel options:

Your current custom EC2 kernel boots with the options root=/dev/sda1 xencons=tty (see end of menu.lst)
The standard XenPV boot options on stock kernels, instead are root=/dev/xvda1 console=hvc0

xvda is the paravirtualized (and more efficient)  disk device, while sda is the less efficient emulated device -- this is the first time I've seen the latter used in a 3.x XenPV.
xencons=tty and console=hvc0 are very similar, but I believe the former is an older (legacy) usage; you can stack them with no ill-effects; it simply tells the kernel that the standard virtual terminal is unavailable for the console, and to use the specialized hvc0 device instead.

How to switch kernels:

This part may be slightly hairy, and you should be in your provider's good books because you may need their help with a simple cp operation once or twice! After that, you'll know what options you need and should be set for the future.

To give you some context if you need it, here are some files from my XenPV VPS on the latest 64-bit kernel: ls -l /boot, menu.lst and a full post-boot dmesg
Add the following at the top of your menu.lst, adapting to the kernel version you need:

default=0
title vmlinuz-3.2.0-25-generic
root            (hd0)
kernel          /boot/vmlinuz-3.2.0-25-generic ro root=/dev/sda1 xencons=tty console=hvc0
initrd      /boot/initrd.img-3.2.0-25-generic

Cross your fingers, reboot, and hope it comes back up!
If not, try changing to root=/dev/xvda1 and that should almost certainly work.
Remember to decline installing "new" menu.lst when upgrading kernels!


18.04 Cannot disconnect from wifi network (eduroam)

To disconnect from the network after removing the file from /etc/NetworkManager/system-connections, I had to restart the network manager:
sudo service network-manager restart

and then it worked.


Can i move the /var folder without having to reboot?

It should be possible but may not be worth the hassle, reboot being the most feasible option.

/var may also contain a database like mysql, various log files and caches. You may have some success doing a lsof | grep /var/ and sending a stop to the related services and most of them may even survive a mv /var /varold && mkdir /var && mount -t auto /dev/whatever /var && cp -Rp /varold /var because they will just stick to their old pid files, but that may crash utterly.

Another approach would be to log in to the server with an account other than root and do a killall -SIGSTOP -u root (or whatever special user they may be running as), do your modifications and resume the processes with killall -SIGCONT -u root.

If this is really mission critical with no downtime and unlimited effort allowance, I would rather setup a cloned virtual machine and mess with that before trying this at the real server.


Run in terminal,

gnome-system-monitor

This would open system monitor.


Cannot connect to internet from VIRTUALBOX

Try creating a Network NAT in VirtualBox and then change the Network settings of your VirtualMachine (Ubuntu 16.04) to the Network NAT you crated.

If that doesn't work, try to swap again to NAT and reboot your virtual machine. Once you are in Ubuntu, press ctrl+alt+T to open a terminal and type sudo service networking  restart


Each Ubuntu version uses a different kernel chain. After upgrading to Ubuntu version 19.04 your kernel version changed. To find the new version number type uname -r. Then use that in your command. For example:

$ uname -r
4.14.110-0414110-generic

$ sudo dkms add r8168/8.046.00 -k 4.14.110-0414110-generic

To reinstall dkms driver for the rtl8168 use:

sudo apt update
sudo apt install --reinstall r8168-dkms

You may not need dkms RTL8168 driver add on with version 5.0 kernel. The RTL8169 driver has been improved in this kernel version as per Linux Kernel 5.0 Released! Check Out The New Features:

Here are some of the major new changes in Kernel 5.0:

AMD Radeon FreeSync support
Support for a new VegaM
NVIDIA Xavier display support
Continued work on Intel Icelake Gen11 graphics
Initial support for the NXP i.MX8 SoCs
Support for the Allwinner T3, Qualcomm QCS404, and NXP Layerscape LX2160A
Intel VT-d Scalable Mode support for Scalable I/O Virtualization
New Intel Stratix 10 FPGA drivers
Fixes for F2FS, EXT4 and XFS
Btrfs file-system restores support for swap files
Fscrypt Adiantum support for helping with fast data encryption on low-end hardware. This replaces the infamous Speck algorithm by NSA.
Realtek R8169 driver improvements
Logitech High Resolution Scrolling support
Raspberry Pi Touchscreen driver
x86 laptop drivers improvement
Thunderbolt security enhancement
Support for the Chameleon96 Intel FPGA board
Improved power management

The RTL8168 driver has been manually installed by many users because of RTL8169 flaws for their network cards.


I also have the same issue

Since I did not want to just allow it - since I don't know what it is - I did this:

Check for programs that are starting after boot by opening "Startup Applications"

And verify that only desired applications do start.
If you have Dropbox (like pointet out by bmaupin) then search for files which you are not the owner of

ls -Rl Dropbox/ |grep -vP 'YourUserName|total|Dropbox.*:|^$'

this Searches for all files where the user is not YourUserName, omits Parent Directories of files and also omits empty lines

Change the ownership of files to your user ($USER) and group

sudo chown YourUserName:YourGroupName /path/do/file


What would be the difference in output between "man ifconfig" and "man ifconfig | less"?

From man man, searching for pipe:

MAN_KEEP_FORMATTING
      Normally, when output is not being directed to a terminal  (such
      as  to a file or a pipe), formatting characters are discarded to
      make it  easier  to  read  the  result  without  special  tools.
      However,  if $MAN_KEEP_FORMATTING is set to any non-empty value,
      these formatting characters are retained.  This  may  be  useful
      for   wrappers   around   man   that  can  interpret  formatting
      characters.

It follows that man may omit formatting in man ifconfig | less, depending on environment settings. As others have noted, man ifconfig itself may not open less, also depending on environment settings (I have set it to open vim).


How to download and install IBM Lotus Sametime Connect 8.5.2 on Ubuntu 13.04 64bit

Below are instructions on how to download and install IBM's sametime on a 64-bit Ubuntu:

download sametime-setup-linux.zip from

"http://sametime.dpteruel.es/sametime/network-install/applet/index_en.html?lang=en"

which will detect your OS and send you the appropriate installation zip file
unzip to get an rpm package
get "alien" package conversion program, like so:

  sudo apt-get install alien dpkg-dev debhelper build-essential

try converting the rpm to deb with alien like so:

  sudo alien --scripts --verbose sametime-connect-8.5.2-20110516.2011.i586.rpm

that didn't work for me, if it works for you then you will get a deb package
and you can install it the usual way.
I got an error saying

  the package is for architecture i386 ; the package cannot be built on this system

my system is an amd64 (aka x64) architecture.
So I found instructions here

http://www.matt-helps.com/using-alien-to-convert-rpm-packages-to-lpia-deb/

which led me to run the following:

  sudo alien --verbose -g sametime-connect-8.5.2-20110516.2011.i586.rpm

  cd sametime-connect-8.5.2

  sudo ./debian/rules binary

Note: the last command is supposed to generate a debian package but it didn't,
      it just copied stuff around. You can also modify the debian/control file and change the target architecture before running ./debian/rules

since I still had no debian package and I noticed that the sametime files are all in ./opt/ibm/ and one executable in ./usr/bin

I simply moved them as follows:

  mv ./opt/ibm /opt/.

  mv ./usr/bin/sametime-connect /usr/bin/.

I ran /usr/bin/sametime-connect and voilà it worked, it asked me for the license agreement and opened the sametime.


I have a mixed system (ATI and NVIDIA) with two displays, which experienced some flickering and other issues.

I had found that basically feeding what xrandr output back into itself would sometimes fix it until the next reboot. So I kept digging. Eventually, I found that clarifying some of the parameters in the xorg.conf file would fix it. But the setup was still a bit temperamental.

NVIDIA has greatly improved the installer for their proprietary drivers (which I need for CUDA, and it use to be a nightmare to keep them up-to-date). With it, they offer to configure the xorg.conf file for you. There is nothing "magic" in the generated configuration, just that it explicitly lists every device and display. Everything has worked since then. Maybe running through the AMD installer just for its configuration of X11 is worth while, even if you revert the drivers afterwards.

If not, then man xorg.conf, but it is dense.


how can i have over 30 users to use my ubuntu with ssh?

Linux is a multi-user OS, so there is no problem with allowing others to access.

To be able to use putty or connect from MacOS terminal students will need ssh client (included in all linux distributions as a standard and MacOS iirc as a ssh binary, or Windows ssh client, like Putty).

Now, on your server you will need ssh server, install it by:

sudo apt-get install openssh-server

If you use ufw - unblosk ssh traffic to your machine:

sudo ufw allow ssh

Now just add users, for example by running:

sudo useradd -s /bin/bash -d /home/[username] -m [username]

Create Password for user:

sudo passwd [username]

Now, that is pretty basic setup, but your students are able to log in to their own accounts and work in shell.

To limit amount of space users can use, use quota application, but it's configuration might be slightly complicated at first glance (https://www.digitalocean.com/community/tutorials/how-to-enable-user-and-group-quotas).

Read also about ssh server configuration, as there are some options like allowing root user to log in that you might want to change (https://help.ubuntu.com/community/SSH/OpenSSH/Configuring).

For user to have administrator privileges, use sudo (see, for example: https://help.ubuntu.com/community/Sudoers)

Remember, that your students machines need to be on the same network for them to be able to connect to your computer (in this, simplest example).


Dynamic MMap ran out of room when trying to sudo apt-get anything

I believe one solution is just increase the value APT::Cache-Limit at the /etc/apt/apt.conf.d/70debconf, to do so use:

sudo gedit /etc/apt/apt.conf.d/70debconf

and add the following to the end of the file:

APT::Cache-Limit "100000000";

..and then run:

sudo apt-get clean
sudo apt-get update --fix-missing


Is there a way to suppress one specific message from syslog?

Since Ubuntu 10.04 rsyslog is used instead of plain syslog and it does have filtering capabilities. Proceed as follows:

Create gksudo gedit /etc/rsyslog.d/01-blocklist.conf
Add the following lines there

    :msg,contains,"Card not present on Slot(0-2)" ~
    :msg,contains,"Card present on Slot(0-2)" ~

Reboot or service rsyslog restart

The solution works as follows:

01- part in file name forces rsyslog to load this config before it loads anything else
the lines in the file find any messages containing the text we want to ignore and discards those messages right away, thanks for discard operator (~)
it is possible to match by regexp or ignore case, check [this helpful guide]
(http://www.rsyslog.com/doc/property_replacer.html) on matching

Note, that solving that kind of issues the right way is always preferred. For example, broken pciehp won't let your CPU to go into deeper sleep states and will increase effective TDP and power consumption of you CPU. However, since pciehp is compiled into Ubuntu kernel, there's little you can do without compiling your own kernel, which is not advisable.


How to get multiple displays working with docking station?

This affected me too. Finally after weeks of frustration I found the solution posted in a Launchpad bug (https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1382462).

In short:

Install CCSM (sudo apt-get install compizconfig-settings-manager)
In CCSM go to "General Options" --> "Display Settings" and do the following:

Un-check "Detect Outputs"
In the Outputs array, set the resolutions of each of your screens.

In my case it was:

  1920x1080+0+0

  1920x1080+1920+0

Now edit your display configuration as usual. In Unity: Dash --> Screen Display


How do I run this script with sudo from the command-line?

You probably need to run the script like:

sudo /path/to/myScript
sudo ./myScript (if the script is in the current directory)

The reason you get command not found is the script is not in the current user's PATH directory. However, using sudo runs it as a different user - root (compare echo $PATH and sudo -i then echo $PATH to see). So of you want to add it to the root user's PATH:

Copy it to /usr/local/bin, /usr/bin/ or another direcotry already in the root's PATH
Add the directory to the PATH, but do it as root (carefully).


webapp : email program on linux for yahoo small biz email

I'm not a java developer, but after a short search I found this tutorial, which seems to be helpful at tutorialspoint.

If you want to send an email via your yahoo account using smtp seems the best way in my opinion, because it's the direct way and obviously there are already a ready-to-use lib.