Runlevels are logical groups of tasks. Traditionally you have five run levels.

0 boot
1 single user
2 not used
3 multiuser
4 not used
5 gui
6 reboot

Each runlevel defines a more or less static set of tasks to run. Runlevel 1, may not have networking while runlevel 3 may not have the GUI login screen. A system goes through all lower runlevels before it reaches the default runlevel. For a typical Ubuntu box, the traditional runlevel is 5: GUI, while other distros such as Debian or Gentoo may come configured to run 3: multiuser as the default runlevel.

In recent versions of ubuntu, this model has changed somewhat because the previous way of starting the system did not allow for multiple services (programs) to run in parallel. Without doubt, there were other reasons as well.

If I understand your objective correctly, you need to run a single command. You can do that by putting it along with any other commands you might have in the /etc/rc.local file:

$ chmod 755 /etc/rc.local

The Init system will not run this file without execution bits

$ cat /etc/rc.local
#!/bin/sh -e
# This script is executed at the end of each multiuser runlevel.

loadkeys  /root/jolemak.iso15.kmap
exit 0

Any multiuser runlevel means any runlevel above 3. In this example, a single command is run to load an alternative keyboard layout for the virtual consoles. It serves as a quick way to fix the layout before I figure out how to properly install and configure additional layouts.

If you need to do more advanced stuff, either write a traditional /etc/init.d/foo script or a new upstart (Ubuntu-specific) /etc/init/moo.conf. Study the examples in that folder and read the wiki for more info.

https://help.ubuntu.com/community/UbuntuBootupHowto
http://upstart.ubuntu.com/getting-started.html
http://upstart.ubuntu.com/cookbook/

Your question is also answered here: http://upstart.ubuntu.com/cookbook/#single-job and here http://www.debuntu.org/how-to-managing-services-with-update-rc-d/


how to install ssh in ubuntu 11.10? getting errors while installing ssh anyone please help me

This is because 11.10 went End Of Life a year or so ago - it would be much better to upgrade to a newer release like 14.04, which is available from here.

An alternative would be to download the packages you need from http://packages.ubuntu.com - e.g. openssh-server server can be found here.
You will likely also need to download some the dependencies as well (highlighted with the red dot - you may have some/most installed anyway).

A much better method than downloading the packages would be to use the method that can be found here:
How to install software or upgrade from an old unsupported release?


After unlocking my sleeping, multi-screen display, some of my windows have moved. Why?

I have had a similar problem in the past. This was caused by the fact that the screen would temporarily revert to a lower resolution (which caused windows and icons to move) during suspend, hibernation, screen locking and/or switching external monitors. Perhaps this is what's happening in your case as well. Have a look here and see if that points you into the right direction.


The window of gnome-calculator ("Taschenrechner" with German locals) is not resizeable. You can't resize it with the mouse either.

You can check that using xprop:

xprop|grep _NET_WM_ALLOWED_ACTIONS

For a gnome-calculator window hat prints

_NET_WM_ALLOWED_ACTIONS(ATOM) = _NET_WM_ACTION_MOVE, _NET_WM_ACTION_STICK, _NET_WM_ACTION_MINIMIZE, _NET_WM_ACTION_CLOSE, _NET_WM_ACTION_SHADE, _NET_WM_ACTION_CHANGE_DESKTOP, _NET_WM_ACTION_ABOVE, _NET_WM_ACTION_BELOW

For a Terminal it's

_NET_WM_ALLOWED_ACTIONS(ATOM) = _NET_WM_ACTION_MOVE, _NET_WM_ACTION_RESIZE, _NET_WM_ACTION_STICK, _NET_WM_ACTION_MINIMIZE, _NET_WM_ACTION_MAXIMIZE_HORZ, _NET_WM_ACTION_MAXIMIZE_VERT, _NET_WM_ACTION_FULLSCREEN, _NET_WM_ACTION_CLOSE, _NET_WM_ACTION_SHADE, _NET_WM_ACTION_CHANGE_DESKTOP, _NET_WM_ACTION_ABOVE, _NET_WM_ACTION_BELOW

Notice the missing _NET_WM_ACTION_RESIZE for gnome-calculator`


dual boot: Windows 8 session lost after Hibernate/Sleep

Using GParted swap the boot flag from /boot/efi partition to the first Windows partition sda1 allowed the hibernate session to start properly. In this case, the Windows Recovery was the first partition.

Since GRUB is installed in the MBR. Setting the flag will not disrupt the GRUB boot loader sequence.

Other solutions are posted here: http://ubuntuforums.org/showthread.php?t=1341694

Also, check if your BIOS has a sleep mode, after turning this feature off the the system boots into the lasted used OS.


How to patch VMware Player 3.1.5 for 32 bit machine with new Lubuntu 12.10 Kernel?

Syntax for patch an application is :

sudo patch `which [APPLICATION]` [DIRECTORY]/[PATCH FILE.patch]

In your case :

sudo patch `which vmware-player` [DIRECTORY]/vmware-715-kernel32.patch


Converting lots of images in pdf-format to jpg-format

You can use convert from imagemagick to convert a PDF into an image.

To install it, use the following command:

sudo apt-get install imagemagick

To convert all PDFs in a directory, go to that directory and run the following command:

for i in *.pdf; do convert "$i" "${i%.*}.jpg"; done

ImageMagick documentation | Bash string manipulation


notify-send not showing notification when playing video

I found the solution myself:

This indeed seems to be a feature which can be controlled by specifying the urgency level with the option -u --urgency=LEVEL (low,normal,critical).

Using notify-send -u "critical" "notification text" will display the notification even if video is played.
Urgency levels "low" and "normal" will not show the notification in the cases described in my original question.


Cannot make Subiquity see zfs zvol block device, like I could with Ubiquity

Subiquity doesn't allow installation to virtual devices, including zvols. The only way I could think of to get around this was to install to another disk, as you would with a zvol, and rsync the contents over from the disk instead, making sure to do the EFI/MBR setup as needed. You could also make a separate partition on your target disk, rsync over after installing, remove the temporary partition and resize the ZFS partition. It's unfortunately cumbersome.

I've opened a bug for this issue here in case you want to add yourself as being affected by it.


Add this file in $HOME/.local/share/applications.

See this.

sts.desktop

[Desktop Entry]
Type=Application
Name=sts
Comment=Spring Tool Suite
Icon=/home/josdem/STS/sts-3.7.3.RELEASE/icon.xpm
Exec=/home/josdem/STS/sts-3.7.3.RELEASE/STS
Terminal=false
Categories=Development;IDE;Java;
StartupWMClass=STS


After upgrade, get blank purple screen. No gdm and can't switch to tty

What I did from the command line is to find the packages for nvidia (dpkg -l | grep nvidia) and then apt-get remove nvidia-173 (or whatever package you get from the previous command).

The problem is that you will still have the nvidia modues listed in xorg.conf. So, I also mv /etc/X11/xorg.conf /etc/X11/xorg.conf_backup and rebooted.

I landed in a graphical mode as usual, without the nvidia GL stuff, but then there are graphical tools to set it up.

At this state, it's safe to delete the xorg.conf backup you just created.


Cron job to move directory with yesterday's date to another directory

You'll need to test this and adjust paths.  Feel free to edit this answer to suit your needs after you do.  But, it's something like this:

#!/bin/bash
THREEDAYSAGO=$(date +%Y/%m/%d --date='3 days ago')
SRC="~/home1/"
DEST="~/home2/"

mv -f $SRC/$THREEDAYSAGO $DEST/$THREEDAYSAGO
cat << EOF >/$DEST/$THREEDAYSAGO/.htaccess
RewriteEngine On
  RewriteCond %{HTTP_HOST} ^example.com$ [OR]
  RewriteCond %{HTTP_HOST} ^www.example.com$
  RewriteRule ^(.*)$ https://example.com/new_directory/uploads/${THREEDAYSAGO}/\$1 [R=301,L]
EOF

Then in your crontab (crontab -e):

# Every day at 12:00am
0 0 * * * /path/to/my/script


Unity crashes after parallels tools installation (Ubuntu 16.04)

QUICK AND DIRTY WORK AROUND

Disclaimer: I've found this "solution" by trials and errors, therefore I can't guarantee it's safe. Use it at your own risk.

Background: when Parallels Tools is installed it copies under /usr/lib/compiz/ a bunch of files with this pattern libprlcompiz_*_*_*_*.so (with digits instead of *). Those are unity plugins and, as it seems, when unity gets loaded the latest version of this plugin is loaded as well.

Now, in my case it happens that unity tries to load libprlcompiz_0_9_12_2.so, which causes the error: Segmentation fault (core dumped).

So my catch was to rename this file and hope that the previous plugin version has no bugs (namely libprlcompiz_0_9_12_1.so). Open a terminal and:

sudo mv /usr/lib/compiz/libprlcompiz_0_9_12_2.so /usr/lib/compiz/libprlcompiz_0_9_12_2.so.backup
reboot

Now everything should work fine after login.

I still have three parallels related processes appearing in unity side bar after login (with a question mark as icon), which disappear after a while.

Let me know if this works for you.


How to boot with Intel GMA500 Poulsbo graphics

OK here is the solution for Sony VAIO P netbooks with Intel GMA-500 graphics to boot 12.04-beta2:

Create a live version on a USB disk (you can use Ubuntu's "Startup Disk Creator" for this) with enough persistent space (about 1 GB is more than enough). Boot this live version on another computer and update all xserver and kernel packages. You can do this by either specifying the apropriate packages or if you're unsure, simply run:

sudo apt-get dist-upgrade

After the upgrade finishes, shutdown and remove the USB disk.

Now boot the updated live version on your VAIO-P. You will probably end up with a distorted display. According to this section of the wiki switch to console (press CTRL+ALT+F1) and restart X using the following command:

sudo service lightdm restart

after this you will have a fine display to continue testing 12.04-beta2 or installing it on your VAIO-P  :)


You may just need to modify the systemd configuration - so run this:

nano /etc/systemd/logind.conf

And then modify the contents according to this or this.

Look for Idle Action, and set it to ignore.
You can also configure IdleActionSec, which should set the time until it carries out IdleAction.

You may also want to configure a few other things, like HandleLidSwitch to stop it suspending when closing the laptop lid etc (I set it to lock -  and is why I know this stuff).

This is partially from memory, but hopefully in the right direction. Any corrections welcome


How to fix an "error while loading shared libraries" issue with Claymore95?

I'm assuming this is an issue with the command parameters, since you say you changed nothing else.

To confirm this, try running:

cd /usr/local/claymore95
./ethdcrminer64 -benchmark

If this runs without errors, move your parameters to config.txt. It should be relatively intuitive, as it should already exist, and contain some instructions. Remember to uncomment the parameters you want to set. Save the file, and make sure the filename is exactly config.txt and that it's located in the /usr/local/claymore95 folder. It could be a good idea to try the default (provided) config options in config.txt first.

When config.txt is set to the parameters you desire, you can run the ./ethdcrminer64 command without parameters:

./ethdcrminer64

If this is successful, change the last line of the startup script to just:

./ethdcrminer64

If this wasn't the issue, please edit your answer to include your logfile and I will take a look.


Xubuntu: Why does my panel no longer show opened programs?

Login as the user with the problem. Right-click the panel and choose Panel > Panel Preferences. This opens the panel-editor. Check in the Items-tab if Window Buttons is listed. If it is not listed, click on the + to add it ( you will have to scroll through the list though ).


Install Nvidia proprietary drivers by running

sudo apt-get install nvidia-346

in terminal. Then reboot.


Where are the files of my /home directory?

ls -l /home

shows you that there are 2 users - sougata and sougatapc. Each of them will have sub-directories in them such as Downloads, Documents, Pictures etc., which you can list by, ls -l /home/sougata. Your files are stored in these sub-directories, most probably and are not lost.

To get a better analysis of your disk, use Disk Usage Analyzer, which will give you graphical view of the disk usage.


Restore terminal background in ubuntu unity

It looks like you are using Terminator which is not the default ubuntu terminal application.

You can try and find the default terminal by Searching for it in the Launcher (Can be opened using the Super Key (Usually with a windows logo on).

Or you can run

gnome-terminal

from your current command line.

If neither of these work then for some reason it has been uninstalled

To install it run

 sudo apt-get update
 sudo apt-get install gnome-terminal

The last option if you are absolutely stuck is do do a right click then preferences to edit the colour scheme to what you want it to be.

If you can boot it from the terminal but not the launcher, let me know so that I can create a desktop icon for you so that you can start it without using a terminal if you don't know how to do it.


Ubuntu 11 display manager startup problem

Scenario like, your Ubuntu GDM(Display Manager) got corrupted due to sudden power failure & it can't be restarted so. Do one thing read this OR this.

This links have good question answered correctly here on this site only.
Hope it'll help you out.


determining what files a package updates / copying software between machines

How do I determine which files comprise an application (built from source, not from a repo), so I can copy it?

The easy solution for most cases is to simply use checkinstall, which will create a .deb file that you can not only install on other (compatible) systems, but also allows you to uninstall the package.

sudo apt-get install checkinstall -y
When done with make, run checkinstall instead of make install
checkinstall will install your application AND give you a .deb file in the current (source) folder which you can simply copy and install on other systems with dpkg -i
Use dpkg -r application-name to remove the application at any time (should also work from Synaptic)

Please see this community help page and the author's home page if you need more information.


I had the same issue. Check udisks2 logs
journalctl -u udisks2.service

In my case there was a bunch of errors related to missing symbols:
failed to load bd_crypto_luks_get_metadata_size: /usr/lib/x86_64-linux-gnu/libbd_crypto.so.2: undefined symbol: bd_crypto_luks_get_metadata_size
failed to load bd_crypto_luks_format_luks2: /usr/lib/x86_64-linux-gnu/libbd_crypto.so.2: undefined symbol: bd_crypto_luks_format_luks2

If you have the same, try to install/upgrade the libblockdev-crypto2 package:
sudo apt-get install libblockdev-crypto2=2.23-2ubuntu3

2.23-2ubuntu3 version of the package has missing symbols.
Hope this helps.
Cheers


open your terminal and type as xrandr then it will display whats the minimum , maximum ,current resolution and with some indexes .

from there a list of resolution display will be shown to you ,so choose whats your desired resolution of the display .

for first resolution give as xrandr -s 0 and for 2nd resolution give as xrandr -s 1 . like that you can choose what exact resolution you want .

hope that helps .
all the best.


When you run Ubuntu in a virtual environment you do not setup any internet settings in Ubuntu unless you are using a usb wifi adapter, in other words if windows is connected to the internet you should have internet working automatically in Ubuntu in the virtual enviroment.

I use virtualbox and I do not have to change any settings to get the internet to work when I am setting up the install, it just works but even if windows is connected by wifi, in the virtual enviroment the icon in the top panel shows an ethernet connection.

Including a screenshot of my internet settings from when I installed Ubuntu in virtualbox.

Have you opened a browser to see if it connects?

To be clear when you run an operating system in a virtual environment it does not see your physical hardware that is why if you have an internet connection in windows the host system you should have an internet connection in the virtual enviroment which is the guest system if the settings are correct when you installed Ubuntu, if not you can change the settings while the virtual environment is turned off.


How to build i386 PPA packages on a 32 bit system

Launchpad doesn't directly support cross-building, although in some cases build-depending on lib32somethingorother-dev may provide a biarch version of libsomethingorother-dev.  Could you link to the failing build?


How can I add Heat to Ubuntu OpenStack single-machine environment?

Our experimental ppa contains a plugin for heat that you can access via the add unit dialog (keypress 'A'). If using our stable package you can do the following to add heat to your stack:

# Obtain the container name
sudo lxc-ls

# Attach to container
sudo lxc-attach <name>

# become ubuntu user and set JUJU_HOME
sudo su - ubuntu
export JUJU_HOME=/home/ubuntu/.cloud-install/juju

# Add heat
juju deploy heat


How can I make running a command depend on the input of a correct password (Tkinter GUI)?

On the edge of being off-topic, but for the sake of gksudo:

Not sure what you want to achieve, since the GUI does not have any effect on what happens in the terminal :)

Then technically

The problem is that you do not set a condition for tkMessageBox.showinfo("Login successful!") to be executed, so whatever happens in os.system("gksudo su && sudo su"), the next line will be performed.

def root_login():
    os.system("gksudo su && sudo su")
    tkMessageBox.showinfo("Login successful!")

How to make it work

First, you shouldn't use os.system any more: Really, really old fashioned.

See below for an alternative coding, using subprocess.check_call:

#!/usr/bin/env python
import subprocess
import Tkinter
import tkMessageBox

top = Tkinter.Tk()
top.geometry("400x250")

def root_login():
    try:
        subprocess.check_call(["gksudo", "su"])
    except subprocess.CalledProcessError:
        tkMessageBox.showinfo("message", "OOOOPS...\nWrong password!")
    else:
        tkMessageBox.showinfo("message", "Login successful!")

def close_window():
    top.destroy()

B = Tkinter.Button(top, text ="Login", command = root_login)
B.pack()
Q = Tkinter.Button(top, text ="Quit", command = close_window)
Q.pack()

top.mainloop()

But again, gksudo su does not have any effect, since you run a GUI :)

Explanation

subprocess.check_call(["gksudo", "su"])

...will raise a subprocess.CalledProcessError in case the password is incorrect, and show the message:

If the password is correct, the message:

will appear.

Note

The try/except/else construction, I did for clarity reasons. The function below does exactly the same, since the function wil "jump" from the line:

subprocess.check_call(["gksudo", "su"])

to

tkMessageBox.showinfo("message", "OOOOPS...\nWrong password!")

in case, and immediately if, the first one raises the subprocess.CalledProcessError:

def root_login():
    try:
        subprocess.check_call(["gksudo", "su"])
        tkMessageBox.showinfo("message", "Login successful!")
    except subprocess.CalledProcessError:
        tkMessageBox.showinfo("message", "OOOOPS...\nWrong password!")


SSH to Icinga2 server doesn't work sadly

Adding firewall-cmd and iptables commands to the Ubuntu server resolved the issue with the:
ssh: connect to host 172.22.10.133 port 50509: Connection timed out

Now:
C:\Users\Username>ssh username@172.22.10.133 -p 50509
Password:
Verification code:
Welcome to Ubuntu 20.10 (GNU/Linux 5.8.0-26-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

6 updates can be installed immediately.
0 of these updates are security updates.
To see these additional updates run: apt list --upgradable

Last login: Thu Oct 29 10:01:44 2020 from 172.22.11.131
Welcome to Ubuntu 20.10 (GNU/Linux 5.8.0-26-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

6 updates can be installed immediately.
0 of these updates are security updates.
To see these additional updates run: apt list --upgradable

Last login: Thu Oct 29 10:01:44 2020 from 172.22.11.131


Just switch the order of the assignments for command and maxruntime and substitute it in command.

maxruntime="15s"
command="/usr/bin/stress --cpu 8 --io 4 --vm 2 --vm-bytes 128M --timeout ${maxruntime}"


Wifi slows Ubuntu to a halt after waking from sleep

I set the following alias in .bashrc (actually in file called alias.sh and then sourcing it in .bashrc)...

alias netre='sudo service network-manager restart'

In this way, I can wake up and just type netre (network reset) in the terminal and the connection resets.


You are probably using the outdated driver from the official repository, if you are looking for better performance you have to install the latest driver;for further information read the tutorials at http://wiki.cchtml.com/index.php/Main_Page .
Anyway i can give you 3 generic advice:

avoid the installation of the closed source official video driver from the official repository, they are really outdated in pratically every distribution
install the official closed source ATI AMD driver trough the creation of the deb packages ( as described in the link posted above )
the AMD ATI driver most of the times needs some tuning because the default settings are oriented to the power saving and a low profile in terms of performance, for say you have to manually enable the anti-tearing effect that otherwise is normal to have with this driver.


The risk of a typo is more than the risk of a bug.

The risk of gaining a habit of "it doesn't work, stick sudo on it!" is much higher than the risk of a bug.

As a sysadmin who's seen people execute all sorts of random commands with sudo that didn't need them, I always caution against superfluous usage of sudo.

While cat isn't harmful, the habit that this encourages is.


Stuck In Login Loop Ubuntu 20.04 (INFINITE)

If you are using nVidia graphics card, use these commands:
sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt update
sudo apt install nvidia-367

If it succeeds, reboot.
sudo reboot

If it doesn't work, try this answer.


Java installation in Ubuntu for topcoder

First of all, I would suggest to uninstall any existing version of openjdk-java or jre, or icedtea-plugin from your machine.

Next, download jre or jdk 1.7 provided by oracle, if you want to use the topcoder arena without any issues in ubuntu.

http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html

Download the tar.gz archive (source) and build it using the instructions given in the readme file.

It helped me, hope it works for you too.
If any issues, let me know.


How to get Ubuntu to recognize an old Windows 95/98 partitioned hard drive?

You should run Testdisk on the drive to fix its partition table. You can install Testdisk by typing :

sudo apt-get install testdisk

Start testdisk with sudo :

sudo testdisk

And follow the Step-by-Step instructions here :
http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step

It's pretty easy and in no time your disk will be fix and you will be able to mount the partitions.


How to start in a specific directory after ssh login?

-t "cd /var ; /bin/bash" worked:

Exec=gnome-terminal -e 'sshpass -p "mypass" ssh myuser@123.456.789.214 -t "cd /var ; /bin/bash"'


In Upstart mode it says that it can't mount /media/sdb2, how do i fix this?

Get into your windows machine. Then download the ISO for the Ubuntu version you are running and make a live boot flash drive with unetbootin. After that reboot and install Ubuntu to the same partition as the faulty Ubuntu, but do not format the partition while choosing and setting up partitions. As long as you don't format your partition, GRUB will be fixed and you will still have all your packages.


How to Find from which folder my PC is taking regular backup via rsnapshot

Only you can answer this as when you configured rsnapshot you should have specified the directories/folders that you wanted to back up and where you wanted them placed onto your computer.

Perhaps you have not really understood the way rsnapshot works?

Here is an (simple) example config that may help:

backup  remoteuser@newjerseyserver:/etc/ newjersey/

The above config is backing up the /etc directory on the remote server newjersey to your local computer's rsnapshot_root defined area in a directory named newjersey.
You would have specified the rsnapshot_root area in your /etc/rsnapshot.conf file - as an example if it was set to /rsnapshots/ then the newjersey etc directory would be seen on your local computer in /rsnapshots/hourly.0/newjersey/etc based on you using an hourly rsnapshot.

If the above is making no sense at all, then google for "rsnapshot tutorial" and read the many sites with articles on rnsapshot with screenshots etc... it will make things clearer.


"Kernel requires x86-64 CPU, but only detects i686" in an Intel Intel Core i7-2600k?

Check to see if your VM's cpu has any additional features enabled like VT (virtualization technology), as well as if the machine is running in BIOS or EFI mode (In virtualbox these are all listed in under CPU, however in VMware player only some are listed the rest can only be configured by editing the vm config file manually in notepad. The best option is to have all such things turned OFF unless you really need them, which is the default setting of most VM softwares.

Check to make sure you choose the correct VM type, for example in VMware Player you would choose Ubuntu 64 rather than Ubuntu when deciding what type of VM profile to use.

If the issues persist, try uninstalling the VM software and re-installing (or if possible updating to a new release).

Last but not least check you HOST bios or uefi, MANY VM PROGRAMS REQUIRE VT or VT-x etc to be enabled on the host to run 64bit vms.


What is the danger of running untrusted software as a normal user

Running untrusted software as a new user is a good start, but it may not be enough.

A lot of files and devices you may consider sensitive are world-readable. Even as an unprivileged user, you can extract a lot of information out of a system (typically you can read /etc for a start).

You may not have your own stuff configured properly. For instance, have you made absolutely sure that this "super-secret-passwords.txt" file is not readable by everyone? And what about this buggy piece of old software running as yourself or root - are you sure it's not writing anything sensitive to disk?

Code running as nobody can go on the internet and download tasks, execute code on your system.

Sometimes a socket on your local system (a unix domain socket) used for inter process communication may not be secured properly (sometimes for good reason), and any process can read and write on it.

Practically, there are things you can do.
You can absolutely check that the program doesn't start anything at boot time. It'll be tedious and you need to understand your system really well though. There are lots of ways a service can be started automatically. (Note: if the program ever ran as root, all bets are off since it could have modified the init system to hide itself)
Top tips for running terrible software

Don't run it.
If you can avoid it at all, don't run anything you can't trust. At least make sure you are making a sound trade-off. Complexity is the enemy of security. The only line of code that's guaranteed to be secure is the line you never run. :)
Run the program in a virtual machine.
Setting up VMs is pretty easy (VirtualBox is great if you don't want to set up any virtualisation infrastructure). This means you'll have a machine that contains no sensitive data (you'd need to have put it there) and you can control the resources it uses. This doesn't give you complete protection of course (It could do things like flood your web server with requests, log in to your lightbulbs via telnet, and so on, plus bugs that let malicious software escape a virtual machines are not very common, but they do happen sometimes).
Run the program in a container.
Containers (LXD, Docker) offer some security for running code on your local machine. They are not perfect. But an unprivileged container provides file system isolation for your program, which is something. Securing containers properly is an art and a science, but it's getting rapidly easier.
Have someone else run the program for you.
This is only slightly relevant to your question, but you can sometimes avoid running old, terrible software, or software that is just complex and difficult to secure properly, by using a third party service. Email is a good example of this. I would not trust myself to have the patience and spare time to host and maintain my own email server. It's a lot of work to keep things like this secure.
Run it as a separate user.
As a last resort, and if you feel the trade-off is worth it, run the program with a new user account specially created for that purpose. I do this with software I trust.

Option 1 is the best. :)
General advice

Your OS is fairly secure. Not completely secure of course, but Ubuntu has a reasonably good track record. Other software you install on it may not be so good. So, run your software on lots of separated, isolated machines. This will ensure that a bug in one program doesn't mean that another program, potentially more sensitive, becomes exploitable.
Go to the web. Today, most end user software has good alternatives that are on the web. On my machine, I pretty much run Chrome and Emacs, and that's it. Using web services has it's own security implications of course.
Go to the cloud (for server software). Are you sure you need to run your own email server? Web server? Database? Go to the cloud and let someone else do all of that tedious security stuff for you.


How to lists different image-formats recursively in a tree?

Install the package tree than use

tree -P '*.png|*.svg|*.xpm' --prune /usr/share/


I was having the same problem with the same adapter, I managed to solve by following the instructions of that response:Bluetooth Broadcom 43142 isn't working


How to view and/or edit a .mdb Jet MS Access database file?

You can try to install mdbtools and mdbtools-gmdb in order to get the mdb viewer for gnome.

I haven't used it myself, so i don't know if it's able to let you edit the database, but it gives you the option to export it, so maybe you can convert it to the oo-base version (odb).

I don't know why openoffice doesn't support it. I've read that is caused by MSDAO that cannot be installed in linux o/s, so only oo-base in windows can natively support it.

Anyway, you should give it a try i guess. I hope it helps a bit.


How to fix overheating and battery low life on ASUS K56CM?

You could try TLP and see if that improves your battery life and temperatures. I've observed almost a 2X battery life improvement on my Lenovo X131e running Kubuntu.

http://linrunner.de/en/tlp/docs/tlp-linux-advanced-power-management.html


not able to update ubuntu or install apps in ubuntu 12.04 LTS

Backup your source.list:

cp /etc/apt/sources.list ~/sourcesBK.list

Download the "example repositories":

wget https://help.ubuntu.com/12.04/sample/sources.list

and reemplace yours:

sudo cp sources.list /etc/apt/sources.list

And try to make an update:

sudo apt-get update && sudo apt-get upgrade


If your panel is jumbled up, you can try reloading the panel by running the following command in a terminal or the Alt+F2 run dialog:

killall gnome-panel


Cannot install shell-themes using gnome-tweak-tool

If you are using gnome-classic session, You can't enable shell theme, simply because you aren't using gnome-shell.

Login to Gnome session, which uses Gnome-Shell. Install the user-theme extension by going to this page. Close the gnome-tweak-tool and re-open it. You should now change the gnome-shell theme

You should also install gnome-shell themes to be able to select a custom theme than the default one.

See this question: How do I get and install more themes, icons, and pointers?


How do I set up ibus to use CJK input for the guest session

While I'm pretty sure those are not the files to copy, I'm not able to tell which files you should copy instead.

But I still have a solution. Create a special purpose user as described in this tutorial and configure that user using System Settings -> Text Entry. Then replace the /etc/guest-session/skel folder with a symlink to the home directory of the special purpose user.


Is is possible to calibrate the battery for my Lenovo IdeaPad S10e laptop?

Letting my battery drain all the way, then rest overnight, then recharge to full did the trick.


I am afraid that you may be a victim of this issue: Thunderbird: localization not installed automatically.
The workaround is run "System - Administration - Language Support" to install the missing Thunderbird language packs.

Please confirm if it works.


Ubuntu 19.04 Software Center - which apps are official / legitimate?

Recently kdenlive dropped support for snap. So I would recommend you install using ppa.

sudo add-apt-repository ppa:kdenlive/kdenlive-stable
sudo apt update
sudo apt install kdenlive


Ubuntu 12.04 Wifi Hotspot can't provide internet for 2 devices simultaneously

May be your wifi card is limited to provide a single channel of communication, so that you will be able to connect to just one device at one time.

You can get USB based wifi cards that support full fledged access point support for around $10 from ebay or amazon


Lubuntu doesn't detect all the RAM (just 1GB of 1,5GB

It isn't the kernel.  The bios always reserves some memory for itself, and if you have an integrated gpu, it reserves a chunk of ram for it as well.  You may be able to adjust how much it reserves in your bios settings.


Can't make cron open a Java program with a GUI

You cannot open a program on your display from cron. Any job you wish to run via cron must not require any services of a logged in user session, including a valid display to place GUI apps on.


You can simply remove any system startup links:

sudo update-rc.d -f kerio-kvc remove

Read more here: http://manpages.ubuntu.com/manpages/hardy/man8/update-rc.d.8.html


How do I remove a color from the GTK scale widget?

Some colors are defined in css style files. Like the one you mention of Scale Widget.

This for Ambiance theme, it's in /usr/share/themes/Ambiance/gtk-3.0/gtk-widgets.css. Here is an example, I have changed it into other color.

.scale.trough.highlight {
    /*background-color: #df784e;*/
    background-color: #02FF00;
    background-image: none;
    background-clip: content-box;
}


Ubuntu 14.04 runs on kernel version 3.13, but the driver for your mouse was only added to later kernels as per bug report #1316768 (note the same USB device ID 04d9:a070).

You can install a newer kernel

as described in Kernel/MainlineBuilds or
in this case more simply with the package linux-generic-lts-utopic from the Canonical Kernel Team PPA:

sudo add-apt-repository ppa:canonical-kernel-team/ppa
sudo apt-get update
sudo apt-get install linux-generic-lts-utopic

Afterwards you need to reboot into the new kernel.


Strange colours in Ubuntu since October 12, 2017

Hopefully this is just a theme change. Try changing theme under settings to any light theme.


Can i just remove the ~/.cache directory?

Short answer: yes.

Long answer:  Yes, but it will fill up again over time, and may cause some minor, but self-fixing issues.


It's usually just the standard pager program (i.e. less or more) and the key to quit is just q


Cannot type after login with Ubuntu 17.10

There's a problem between some Logitech keyboards and fwupd https://bugs.launchpad.net/ubuntu/+source/fwupd/+bug/1717340. I used sudo apt remove fwupd typed with a virtual keyboard to get rid of it and my keyboard worked after a restart. I also had an issue with the virtual keyboard where the shift button wasn't working, so I had to use the special characters map to enter my password.


How to configure the guest vm(Ubuntu16.04) to get ip from bridge network of the host vm(Ubuntu16.04) using KVM hypervisor?

I used netplan to get bridge ip here is the configuration file to netplan

sudo vim /etc/netplan/01-network-manager-all.yaml

network:
  version: 2
  renderer: NetworkManager
  ethernets:
    enp9s0:
      dhcp4: true
  bridges:
    br0:
      dhcp4: true
      interfaces:
        - enp9s0


I can't backup mongo with mongodump and cronjob

Put the command into shell script and set the cronjob to run that shell script but not mongodump command


Your thg binary executed by default is installed in /usr/local/bin. This location is not managed by APT, so it wasn’t most likely installed by APT (or it has been moved/copied from the default location).

To uninstall it, just remove the file /usr/local/bin/thg (you’ll need sudo for that).

You can also keep using both versions but you must provide the full path when launching the non-default version. The version installed by APT should be located at /usr/bin/thg.

If you suspect there are even more thg versions in your system, you can find them all using the command:

find / -name thg


How to pause an application when minimizing a window?

For videos specifically there is SMPlayer that supports the functionality you're searching for. Install it via the software center or by typing in a terminal:

sudo apt-get install smplayer

Then set SMPlayer to pause when minimized by heading to Options -> Preferences -> General -> Pause when minimized:

I am using UMPlayer in that example, but the same procedure works with SMPlayer as well.

Here’s a screenshot from the SMPlayer Preferences dialog:


Try disabling intel_pstate through Linux kernel options as described here.


Wine is still not very good at removing programs, so your options may be rather slim. This is actually a problem inherited from the way Windows manages installed applications, so it won't change any time soon either.

You could manually remove the program's files from your virtual "C:\" Drive, then open the uninstall center and remove that application from the list. However, it is possible that the program will leave some cruft behind.

My best suggestion is that you use something like PlayOnLinux or WBM (Wine Bottle Manager) to manage your WINE applications. Even if there is not a script in PlayOnLinux for your application, you can still install it to a separate WINE prefix, and make uninstalls easier.

If you don't have too much to lose, you can go right ahead and remove your ~/.wine folder (run rm -r ~/.wine) (backup first just in case), then reinstall the applications you need. Chances are, it may even fix your Spotify problems.


Trying to use Adapt based on LXC/LXD: couldn't find requested image

While looking for an answer for this question: How use Adapt application I ran into the same problems you mentioned.

I found this bug and used sudo lxc remote remove images, after which adapt works - I do not know if this fix is needed after every reboot or only after the first start - didn't test it. But makes it work.


How to enable PostgreSQL driver for PDO for php 7?

You've been running php7.1 while you installed php7.0 pgsql module.

Try php -v to check your version and install php7.1-pgsql.


Screen share show black screen after upgrade from Ubuntu 20.10 to 21.04

Looks Ubuntu 21.04 default to Wayland, when I switch to Xorg screenshare works fine.
If anyone wants to try this. These are the steps:

In the login screen, click the setting icon
Choose "Ubuntu On Xorg" instead of "Ubuntu"
Now login

Screenshare should work now.


Installing Nvidia driver helped me. From command prompt:

sudo apt-get install nvidia-384


Install Ubuntu in dual boot on an encrypted partition

Short answer: stick to the default of ext4, unless you know why you want something different. The Ubuntu installer offers the option to encrypt your partition for you using LUKS, however if you wish to use TrueCrypt then you should encrypt the partition before you install! Note that TrueCrypt is no longer being developed and it is uncertain if it is still safe. TrueCrypt has been forked under the name of VeraCrypt. Ubuntu can read NTFS so that should be fine. Windows however can't read ext4 without third party drivers and therefore can't read your Ubuntu partition.


Kubuntu 16.04  15.10 Inconsistent and slow wirless network transfer speeds

In the end, the KDE applet from the toolbar where you choose the network connections seems to be flaky.  I used the system monitor and could show ~50% network saturation during transfers in both directions.


According to the Linux Wireless wiki, you need to have a kernel version of 4.3 or later for this wireless card to work.  Your current kernel is probably 3.19, since you're on a fresh install of 14.04.  In a terminal, type this to see your current kernel version:

uname -r

Assuming that you have an ethernet connection, you can install kernel version 4.4 by running this command in the terminal:

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

Once the kernel install finishes, restart your computer, then follow these instructions from this bug report:

  1) Get the latest firmware from https://github.com/kvalo/ath10k-firmware/archive/master.zip

  2) Unzip this file, and copy the contents of ath10k-firmware-master to /lib/firmware/ath10k.

  3) Rename two of the firmware files like so:

cd /lib/firmware/QCA6174/hw2.1
sudo mv firmware-5.bin_SW_RM.1.1.1-00157-QCARMSWPZ-1 firmware-5.bin
cd /lib/firmware/QCA6174/hw3.0
sudo mv firmware-4.bin_WLAN.RM.2.0-00180-QCARMSWPZ-1 firmware-4.bin

  4) Reboot your computer. Run "lshw -C network" to see if your card is recognized.


I advise you to use virtual machines as the following article says :

Xen
VirtualBox
VMware
QEMU
Microsoft Virtual PC
Parallels


You need to do two things (I think). Firstly, create a local repository. The steps for doing this are already well documented (see https://help.ubuntu.com/community/Repositories/Personal).

Then, place the folder structure for this repository in a public directory on a web server, make the folder structure public, and have users update their software sources or /etc/apt/sources.list file with an entry to point to the repository on your file server.


Installing Wine On a different USB device to Ubuntu

Create a bootable USB with persistence mode (same kind of settings in other usb creator is also available).

Boot using it, install wine and other applications.


How to modify the details of a debian package

The usual way to do this would be from a source tree. You would get a source tree by either downloading it or executing a command such as apt-get source some-package.

Once the source tree is downloaded, you would follow these steps:

cd some-package*/debian
nano control
The control file holds information for the source tree and packages generated from the source. For the source tree, there are several fields including "Build-Depends", "Maintainer", "Section". For the package, there are fields such as "Architecture", "Depends", "Suggests", and "Description".
nano changelog
This is the version file that contains the changelog for this package. Simply modify the version number, or add your own section above it with your own version number.
debuild -us -uc will re-build the package with the updated information

However, it's theoretically possible to do this by simply extracting the Debian package. (Note, I did not test this).

ar x SomePackage.deb
tar -xzf control.tar.gz
nano control and edit the information
tar -czf control.tar.gz conffiles control md5sums postinst postrm preinst prerm
ar r SomePackage.deb control.tar.gz
rm control.tar.gz data.tar.gz debian-binary conffiles control md5sums postinst postrm preinst prerm


Is zfs-dkms required for ZFS support in generic kernels?

From Ubuntu Wiki ZFS:
ZFS
Summary
ZFS is a combined file system and logical volume manager designed and implemented by a team at Sun Microsystems led by Jeff Bonwick and Matthew Ahrens. Its development started in 2001 and it was officially announced in 2004. In 2005 it was integrated into the main trunk of Solaris and released as part of OpenSolaris. Currently, as of January 2015, it is native to Solaris, OpenSolaris, OpenIndiana, illumos, Joyent SmartOS, OmniOS, FreeBSD, Debian GNU/kFreeBSD systems, NetBSD, OSv and supported on Mac OS with MacZFS.
The name "ZFS" originally stood for "Zettabyte File System". Currently it can store up to 256 ZiB (zebibytes).
Installing ZFS on Ubuntu
The ZFS filesystem is available for Ubuntu as either a FUSE module or a native kernel module. The kernel module is provided by default. To install the user-level tools, simply install:
sudo apt install zfsutils-linux

For all current versions from 16.04 onward.
In addition to be able to have ZFS on root, install:
sudo apt install zfs-initramfs

No where is it mentioned that zfs-dkms is a prerequisite.

kABI
kABI is the Kernel Application Binary Interface. It doesn't change very often but when it does all programs must share the same version.
Tracking ABI/API changes
From the ABI Labratory we can see the last changes were on June 4, 5 and 6th, 2018:

We can see the Linux Kernel numbers revised in June 2018 were:

4.14.48, 4.9.107 and 4.4.136 all 6 year LTS kernels

The corresponding Ubuntu Kernel version numbers were probably:

4.13.0-43 headers failed to install: Linux kernel header files to match the current kernel
4.15.0-23 apt removal script broken

We need to upgrade Linux Kernels when new hardware support or bug fixes to existing hardware are released. When an ABI/API change is involved the Ubuntu kernel may or may not work. Even if an ABI/API change doesn't take place the Ubuntu Kernel may still break for some people for other reasons.
If you have a generic Ubuntu Kernel and a Linux Mainline kernel after June 2018 in this example, they would both share the same kABI.


No audio in Ubuntu 16.04, Intel Corporation Device a171 (rev 31) Audio device

I solved it by resetting the default audio configuration according to http://www.utdream.org/post.cfm/resetting-pulseaudio-on-ubuntu-13-04-new-sound-card

Remove alsa-related softwares and pulseaudio :

sudo apt purge alsa*

sudo apt-get remove --purge alsa-base pulseaudio indicator-sound

Reinstall them :

sudo apt-get install alsa-base pulseaudio indicator-sound

Then type :

sudo alsa force-reload

Then reboot.

At start, open the pulseaudio volume control (from the Whisker menu or typing "pavucontrol" in a terminal). Click on the top-right arrow (that I had not noticed at first sight) to the "Configuration" tab and select "Stereo Analogic Duplex".

Now move to the first tab ("Lecture" on my french release, might be "Play" on an english one) and unmute the output by clicking the Headphone icon.

Sound came back right after this click (no need for a reboot).


What are the make/build/install commands for module?

That uses dkms. Sources of the kernel module are in the bcmwl-kernel-source deb package. They are compiled to get kernel module (*.ko file) when the bcmwl-kernel-source package is installed or the kernel package is upgraded.

So, it doesn't affect the system too much: just an additional kernel module.


Pulseaudio loopback makes pavucontrol malfunction

I found out what was wrong. Module-loopback had nothing to do with the matter. It just couldn't work properly with the sample rate parameters I've declared earlier in the daemon.conf file and crashed with this error displayed by the OS:
"pulseaudio crashed with sigfpe in pa_resampler_max_block_size()"
Problem solved, then...


How can I execute a .jar file from the terminal

The . syntax can only be used to run (by "sourcing") shell scripts.

You'll need to use the java command to run a .jar file:

java -jar Minecraft.jar

If you don't have java installed, you can fix that by installing the default-jre¹ package. You can see if you already have java installed by running in a terminal:

java -version

[1]: This will install the default openjdk Java runtime. You can use openjdk-8-jre, or openjdk-7-jre, or openjdk-6-jre instead, if you prefer - whichever is available on your version of Ubuntu.


Sounds like your Compiz and/or Unity settings are screwed up.

Try the following. First of all, since you can't fire up a terminal when in X, switch to non-graphical mode:

Hit Ctrl+Alt+F1. This will get you to the non-graphical mode.
Login there with your username and password.

Now from here, we'll try to reset your faulty configuration.

Option 1: Reset Compiz configuration

To reset only the Compiz settings, execute the following commands:

DISPLAY=:0.0 dconf reset -f /org/compiz
rm -r ~/.compiz* ~/.config/compiz*

This should restore your Compiz settings to default.

Finally, restart X (i.e., the graphical mode):

sudo service lightdm restart

Option 2: Reset Unity configuration

If the above doesn't solve your problem, try yo completely reset your Unity configuration. From this answer, you can use the unity-tweak-tool for this. You'll have to install it first:

sudo apt-get install unity-tweak-tool

Then, execute the following command:

DISPLAY=:0.0 unity-tweak-tool --reset-unity

Finally, switch back to X by hitting Ctrl+Alt+F7.

Hopefully, one of these will fix it.


Put down the doobie, you're fine. (jk)

Coming to you from Ubuntu 17 on an HP Envy. All is well. If you like your Windows apps, do a little research and learn to use WINE. You'll fall in love with your computer all over again.


This is a common problem with Wine/Steam. I encountered it and here's what I did to make it work. Make sure to have your wine compatibility set to Windows XP for Steam while running the exe with the "-no-cef-sandbox" argument.

Example : "wine Steam.exe -no-cef-sandbox"

This can be done in PlayOnLinux by following these steps:

Highlight the program you wish to run and click configure (Steam in this case (I just renamed it to Steamwine when installing it))

Now enter "-no-cef-sandbox" into the arguments box.

It should look like the box below when you are done:

Now go over to the Wine tab and click "Configure Wine"

And make sure the "Windows Version" is set to "Windows XP"

Now click okay once Windows XP is the Windows Version that is set, and close out the PlayOnLinux Configuration window. You may need to quit PlayOnLinux for changes to apply.

Sources:
https://forum.winehq.org/viewtopic.php?f=8&t=28640
https://www.playonlinux.com/en/topic-15371.html
https://forum.winehq.org/viewtopic.php?f=2&t=29066
https://appdb.winehq.org/objectManager.php?sClass=version&iId=19444


You could use VLC to convert mpeg files to mp4. To do this:

Open VLC
Click on Media in the menu bar and select "Convert / Save"
In the "File" tab, click on "Add..." button and choose the file to convert from the file browser dialog box that opens up
Click on "Convert / Save" and verify that the source file is exactly the one which you want to convert and give an appropriate file name for the destination file, appended with ".mp4" and choose the format for the destination file. In your case this would be "Video - H.264 + MP3 (MP4)" and then click on "Start"

This may take some time depending upon the length of the file and when it finishes, voila! You have your file ready.


What does apt install --fix-policy actually do?

Hmmm, according to this (old) bug report, and related mailing list post, --fix-policy is actually a neat option to make apt reconsider the "Recommends" dependencies of installed packages. So, originally if you had installed a package without its recommended packages, you can get it to install these extra packages by using --fix-polcy:

  If you want to see what would change if you had a system with
  --install-recommends please run:

# apt-get install --fix-policy --install-recommends

  If you want to know what package causes the installation of what
  recommends please run:

# apt-get install --fix-policy --install-recommends -o Debug::pkgDepCache::AutoInstall=true

The option has been around for some 11 years now, and the bug report asking for it to be included in the manpage for 8 years now.

So, I get, for example:

$ sudo apt-get install --fix-policy -o Debug::pkgDepCache::AutoInstall=true
Reading package lists... Done
Building dependency tree
Reading state information... Done
  Installing iio-sensor-proxy as Recommends of gnome-settings-daemon
  Installing indicator-printers as Recommends of unity
  Installing cinnamon-l10n as Recommends of nemo
  Installing nemo-fileroller as Recommends of nemo
  Installing python-bs4 as Recommends of python-lxml


ZFS pool with disks labels /dev/disk/by-id/scsi*** disappeared after upgrade

You should be able to use the command zfs import to scan your disks for pools and rebuild them.

Use zfs import for a list of pools and zfs import <pool> to import any detected pools and their configurations.

zfs import will scan all the devices for pools and configuration and attach the found devices to their rightful pools, no matter the name of the device on the your system, if the disk is present zfs will set it online.


Change X settings to boot into laptop with non working screen using an external monitor

Just plug in a monitor, and the monitor will mirror what the laptop screen ought to be showing. You can use System -> Preferences -> Monitors to get the resolution right, and turn off the laptop screen (so Ubuntu doesn't try to render everything twice).


I hope the string is a lot longer than that. The one you've given is barely a fragment of header. But the following should work (it did partially with your example):

xxd -r -p file.txt file.jpg

So if you've got a whole bunch of these, we can script something up to process them all:

find -name '*txt' -exec xxd -r -p "{}" "{}.jpg" \;


I think you will not be able to find a IDE for .NET in linux that is as powerful as Visual Studio. I am using MonoDevelop, which is quite decent IDE. I have problems when debugging because watching variable does not always work, but other than that it works as expected.

Regarding WPF, I believe you cannot do it in Linux. You must be aware that Mono, which works great in Linux, is a subset of .NET and will probably never support everything that is available in Windows. I was surprised that so many things work, which I didn't expect too. Take a look here for WPF: http://www.mono-project.com/docs/gui/wpf/.


Is it possible to install amd64 software on aarch64?

Your pinebook is Arm 64 bit architecture, not AMD 64. The Arm Cortex uses different instruction set as the Amd processors. Thus the binary packages are not compatible. You can contact the VPN unlimited support for the ARM 64bit package. Be sure you specify your system.


Solve screen tearing with nouveau (without switching to proprietary Nvidia driver)

So the solution that worked for me was to switch to Wayland instead of X11. Wayland uses nouveau, and there is no screen-tearing when playing videos.


How do I clear up textures on my desktop?

You can install compizconfig-settings-manager. Open ccsm, and click on the OpenGL tab to change the settings.

First, make sure this plugin is enabled. Next, on the "texture filter" setting, change the setting to "Best"

Also, go to "General Options" and to the "Display Settings" tab. Make sure "Detect Outputs" is enabled. Then, I'm not sure if it will work, but you can try clicking "Edit" and manually setting the resolution to 1366x768+0+0.

Next, make sure you have enabled the "Composite" plugin and do not enable "Copy to Texture".

Finally, scroll down to "Effects" and disable "animations" and any other effect as well (make sure all the effects are disabled).


All v3 kernel distributions can be found @ http://www.kernel.org/pub/linux/kernel/v3.0/


You can use the jq tool (available via apt-get) for that.

If the file ip.json has a json object that each key is a different host. Following your example (for any reason, you can not use local alias on zsh without getting issue with completion)

{
  "Local": "127.0.0.1",
  "remote": "192.168.0.5"
}

You can append this to your zshrc file:

# Use jq to get all keys in the root object and create a loop
for host in $(jq --raw-output 'keys | .[]' ip.json); do
  # Get the key value of these keys and create the alias
  alias $host=ssh\ root@$(jq --raw-output ".$host?" ip.json)
done

Use man jq for more information about this tool.


Brightness Keys(Fn+F5, Fn+F6) Not Working on ASUS K501UX in Ubuntu 16.10

The fix as mentioned by Pilot6 above is this:

gksudo gedit /etc/default/grub then change the command line to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="

and run sudo update-grub


How to respawn automatically a process(wso2am)?

I have solved this issue with help of Wso2 Team. Here, we have mention step for
system-D configuration issue.

System-D script for wso2am.service service file.

[Unit]
Description=wso2am server daemon
Documentation=https://docs.wso2.com/
After=network.target

[Service]
ExecStart=/bin/sh -c 'XXX/Wso2serve start'
ExecStop=/bin/sh -c 'XXX/Wso2server.sh stop'
ExecRestart=/bin/sh -c 'XXX/Wso2server.sh restart'
PIDFile=/xxx/wso2carbon.pid
User=<Username>
Group=<groupname>
Type=forking
Restart=always
RestartSec=2
StartLimitInterval=60s
StartLimitBurst=3
StandardOutput=journal

[Install]
WantedBy=multi-user.target

Now when you search for the wso2am process, use the below command.

ps -ef | grep java

Then pick the PID for the wso2am java process and kill it.

kill -9 <wso2_server_PID>

Immediately run

ps -ef | grep java

again and see that the process is not there now. Then within 2 seconds as we have specified RestartSec=2, you will see the wso2 server process is back up and running with a different PID

Thanks,
Vivek KT.


That's pretty simple. Find another usable PC and follow the steps. First you'll have to download the Ubuntu (or one of its flavors) ISO image from ubuntu.com/download. If you are using Windows 7, download the program UNetBootIn (unetbootin.sourceforge.net). This program allows you to make a bootable flash drive with Ubuntu ISO. Follow the steps of the program.

After you're done, plug your USB stick and restart your PC. When you see your BIOS, you have to enter its Boot Device Selection Menu (usually pressing Del, F2, F10 or F12). Select your USB and Ubuntu Live will boot. You can install Ubuntu on your PC from there.


How can I upload video on Youtube and pause or resume it?

Use the web uploader inside Chrome or Firefox - it has auto-resuming capability so that you can disconnect your Internet connection to pause the upload and then reconnect when you wish to continue the upload.

If you want to avoid losing Internet access from other programs, just change temporarily the browser's network settings to e.g. some non-existent proxy. This will kill connectivity just in the browser.

If you need browser access, either start the uploading in a separate/dedicated browser, or use some browser extension that let's you set proxy settings on a per-tab basis.


Should I defragment my hard disk before installing using WUBI?

You should indeed defragment your hard disk before installing ubuntu. You should also make two backups of all your files and make sure you know what you are doing. In other words, read everything on WUBI install you can find on this website.


If you use proc_open instead of exec, you should get more control over the file descriptors.


Batch command that reqiures output redirection

You forgot to quote $f, so the filename probably got wordsplit due to whitespace in the filename. I also suggest using ./*.dvi as this avoid problems if a filename starts with a - (which will make most commands treat it as a set of options instead of a filename)

for f in ./*.dvi; do catdvi -e 1 -U "$f" > "${f%.dvi}.txt"; done

Or perhaps combine the two loops

for f in ./*.tex; do
    base=${f%.tex};
    latex "$f" &&
    catdvi -e 1 -U "$base.dvi" > "$base.txt";
done


Nautilus "unable to mount " and "not authorized" and LightDM keeps sending me back to login screen on shutdown and restart

This was happening to me. It looked like the upgrade removed the partition entry from /etc/fstab. Try putting it back in.


Does SafeNet Token and Openvpn work on 11.10?

I have found a way to make it work ! at least token work fine for everything now :

http://sck.to/X8 (little tutorial).

Tell me if it's ok for you.


Setting up alias for specific folder for specific command

You should use full paths. Instead of 2fa, use $HOME/dir/2fa.


It did not change... It has always been like that! (See the cases below.)

If you are dragging across storage devices and/or environments: ([SSD, HDD] ⇢ [SSD, HDD], [Local, Network] ⇢ [Local, Network]), then it will copy.

If you are dragging across directories/folders on the same storage device, then it will move.

As you are now aware of this, there's no issue anymore.


It's just called Ubuntu, sometimes together with the "vanilla", "plain" or "default" attributes you used as well to make sure you mean the default and not any of the Ubuntu flavours like Kubuntu, Xubuntu and so on. There is no special other name for it though.

In case you were trying to ask about the name of the desktop environment used by the "default" Ubuntu, that would be Unity until release 17.04 and GNOME again since 17.10.


after Kubuntu 20.04 auto update all monitors not recognized correct (default)

i reused the good anser here from 2013 https://askubuntu.com/a/373573/1017209
with a very little update.
i could not answer what happens while this update was running last night, but this helps.
this did not solve the little other problem with the configuration of the scceenshot tool. My guess is that there might have been a brief power outage while the system was shutting down.

remove all nvidia bits
install the correct drivers:
reboot

sudo apt-get purge nvidia*
sudo apt install nvidia-driver-455
sudo reboot


Cannot configure static IPv6 (Ubuntu 19.04)

Two things to check, 1. are you using a correct ipv6 private IP, 2. is your system correctly configured to use netplan xor ifupdown (I assume ifupdown as you are using /etc/network/interfaces file).

If you do not have a valid IPv6 address range from your ISP, you can use a private address, in the special IP range of fc00::/7 (as per RFC4193). Note that such addresses will always start with "fd" because the 8th bit must be one (hence fc00::/7 bits). The global ID and subnet ID must be random, and then you can assign anything for the rest (interface).

The addresses fc00::2:0:0:0:a and fc00::3:0:0:0:a are not valid private IP's. Should be fd00:: etc. assuming that was the intention. This could cause issues when assigning the IP's. Try using one of the many online services to generate the private IP's using a certified random generator.

Check for netplan vs ifupdown:

netplan (backend: Network-Manager Desktop GUI or systemd-networkd service):

systemctl status systemd-networkd.service
systemctl status NetworkManager.service

Check what netplan is doing when it creates interfaces using:

netplan --debug generate --mapping enp0s8

ifupdown (backend: networking)

systemctl status networking.service

Check what interfaces ifupdown actually configured:

cat /run/network/ifstate

And ensure that the ipv6 interfaces are listed.


You can add a "Standard" account (from Settings -> Detail -> Users -> Add user).

Standard users can use software like Firefox, IDE, a music player, or download files, read their own. They can also change settings that only affects themselves, such as his wallpaper.

Standard users cannot install/upgrade/uninstall software or change system-wide settings, e.g. WLAN password.
Standard user can read/copy documents and photos in your Home directory and any file or created elsewhere but not able to modify/delete them.


How to make Google SketchUp work with Intel graphics in Wine?

I've installed SketchUp 8 and had the same error.

Here's how I got it to work:

Open a Terminal, or press Alt+F2 and type

wine regedit

Navigate to HKEY_CURRENT_USER → Software → Google → SketchUp8 → GLConfig → Display
Change the value of HW_OK to 1 (so that it shows up as 0x00000001 (1))

Then start SketchUp

I hope this works for you as well :)


My machine has running multiple application but in top utility it is showing only one process. Is it a bug in top utility?

The Unix system use the CPU in a way it simulate running a lot of processes in parallel.

Actually only one process can run in each CPU at any point of time.

The other processes might be in other state (e.g. sleeping)

More info can be found here

In the example in the provided link, there are 4 cpu's, and 2 running processes.


Strange networking problem. Google does not work

After trying a ton of things, I got frustrated and just reinstalled Ubuntu. Since then, the problem seems to have gone away.


I thought there would have been a HiDPI setting in the Unity Tweak Tool, but I can't find anything. I'm running Gnome on my Ubuntu installation, and found that the Gnome Tweak Tool has a HiDPI setting where you can scale up to your heart's content. My Macbook isn't retina, so I cannot confirm that this will work with complete certainty, but it might if you're willing to try out Gnome.

sudo apt-get install gnome-shell ubuntu-gnome-desktop gnome-tweak-tool

Choose LightDM when prompted. When complete, log out and you will now find a small icon to the right of your username on the login screen. Clicking that icon will offer a choice of shell to use. So, select Gnome, and login. Then run "gnome-tweak-tool" from the command line or find it in the applications, which popup with CMD+A.

From the Gnome Tweak Tool, select the "Windows" section on the left side-pane, where HiDPI is the last entry on the right.

If this works for you, at least you have a solution until someone writes a HiDPI setting for Unity. And at any time you can switch back and forth between Gnome and Unity, so you don't have to commit to anything.


The files are maybe protected by Windows Media DRM. One solution is to play and record them without DRM with your windows system, another is to use a tool like FreeMe2. You could also burn the files as audio cd and rip them again.

The Free Software Foundation calls it: "Digital Restrictions Management".

Tip: Stop using Windows Media Audio. Use another audio file format such as Mp3 or if you are an idealist Ogg Vorbis. If you love lossless sound you could use FLAC. See also the comparison of audio formats.


How to type into the lightdm login screen from the command line?

Here is an answer that works under Ubuntu 16.04 with lightdm:

Make yourself root to get access to the lightdm's .Xauthority, which is located under /var/lib/lightdm/.Xauthority. Either copy it somewhere where it will be readable by you and drop your root permissions, or simply remain root.
set XAUTHORITY to point to that file (e.g. export XAUTHORITY=/var/lib/lightdm/.Xauthority)
set DISPLAY to the active display (export DISPLAY=:0)
xdotool should work now. Try

xdotool type "My super secret password"
xdotool key Return


pecl install zip giving error ubuntu 12.04

Perl compatible regular expressions - PCRE libraries is missing (...fatal error: pcre.h:...), because you are compiling module you should add dev packages too:

sudo apt-get update
sudo apt-get install libpcre3 libpcre3-dev


Theoretically you can try the downgrade. Use synaptic to do this.


Any way to extract the current subtitle line from MPlayer

No. This is all you can do with subtitles and extracting them. Depending in the type of file you can use:

MPsub: -dumpmpsub
SubRip: -dumpsrtsub
MicroDVD: -dumpmicrodvdsub
JACOsub: -dumpjacosub
Sami: -dumpsami

There are some more on that site but all will extract all lines and not just the current line.

So to get a specific line you need to extract the subtitles to a text file. Examine the text file, locate the timestamp you need and the copy/paste the line. It can be automated to an extent but getting the timestamp to find the line is manual work.


KDE4: move window to another workspace by dragging?

System Settings > Workspace Behavior > Screen Edges; Switch desktop on edge: Disabled/Only When Moving Windows/Always Enabled.

KDE Userbase: http://userbase.kde.org/System_Settings/Workspace_Behaviour

  In the Screen Edges module you can choose between certain actions to
  be triggered when the mouse moves to one of the edges or corners of
  the screen. Each edge, and each corner can have its own action
  attached. You can also decide whether you want windows to be maximized
  when you drag them to the top edge of the screen, or to be tiled when
  you drag them to the sides of the screen. Finally you can set what
  happens to windows when you drag them across the screen edge.


What you should do is to add an & and the end of chromium-browser 'www.amazon.com'.

The & informs the shell to put the command in the background, your shellscript should look like this:

#!/bin/bash

chromium-browser 'www.amazon.com'&
sleep 2
chromium-browser 'www.ebay.com'&
sleep 2

You have to send the task to the background because otherwise the terminal can not execute the commands after your first call tochromium-browser 'www.amazon.com'

Hope this helps.


I modified the printer to use the HP LaserJet 2200 CUPS+Gutenprint v5.2.9 and now it seems to work fine.  I tried Okular-it worked before the modification.  However, evince and firefox did not.  I also tried generic postscript as the printer (which almost always works), however, it did not this time - only the Gutenprint driver worked.


What do I multiply in this matrix calculation to configure my touchscreen?

If you want to scale the y coordinate, you should multiply 0.71111 by your scaling factor 1.2. The general formula is:

if the matrix is

a b c
d e f
g h i

then the formula is

new_x = (a * old_x + b * old_y + c) / (g * old_x + h * old_y + i)
new_y = (d * old_x + e * old_y + f) / (g * old_x + h * old_y + i)

This is a projective transformation. In almost all cases (meaning, all cases unless your display is a beamer that projects skewly on a wall), you just need a linear transformation, so you  set g h i to 0 0 1.

If you're ever going to do more advanced stuff, then you should know that for the porpose of this calculation, old_x/new_x etc are in the range between 0 and 1.


What is wrong with my attempted setting up of TightVNC as a service?

Based on discussions in comments and chat, the issue was resolved by re-running the setup procedure after the addition of the user whose desktop was to be shared.


Executing the following commands would install expected ct library.

sudo apt-get install freetds-bin freetds-dev freedts-common


gnome-terminal backgroud and foreground colour issue

foreground-color and friends are of type string. If you perform a dconf read ... on the said field, the output will be quoted within single quotes, e.g.:

'rgb(0,0,0)'

To write such a value, you have to pass those literal quote characters to dconf, that is, you have to protect them from your shell from being parsed as special characters.

One possible way to protect them is to enclose the entire string within double quotes, e.g.:

dconf write ... "'rgb(0,43,54)'"


How to spawn/trigger a command upon entering specific workspace

Introduction

Essential workflow of this solution is to have a wrapper script that starts user's command upon entering workspace, and sends sigterm to it when user enters workspace not on the list. This is best used with commands that can be used as standalone applications and can be safely terminated without loss of information

Usage

As shown by the -h option

usage: workspace_command_limiter.py [-h] -w WORKSPACES -c COMMAND

Runs user-defined command __upon__ entering user-defined set of workspaces.
For instance ./workspace_command_limiter.py -w 1,2,3 -c "python
/home/user/some_script.py" This is intended to serve only as launcher for a
command when user switches to their desired workspace, so consider carefully
which command you want to use. NOTE: This script does run everything from
shell, so you are here implicitly trusted not to use any command that may
break your system. I'm not responsible for your stupidity :)

optional arguments:
  -h, --help            show this help message and exit
  -w WORKSPACES, --workspaces WORKSPACES
                        coma-separated list(without spaces) of workspaces
  -c COMMAND, --command COMMAND
                        quoted command to be spawned,when switch to workspace
                        occurs

In the context of disable_super_key.py script , this should run like so

./workspace_command_limiter.py -w 1,2 -c "python ./disable_super_key.py"

Note, that in this example , ./ indicates that both scripts are in the same directory.

Script source

Also available on github

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Author: Serg Kolo , contact: 1047481448@qq.com
Date: August 24th, 2016
Purpose: Runs user-requested command only on specific workspaces
Tested on: Ubuntu 16.04 LTS , Unity desktop

The MIT License (MIT)

Copyright © 2016 Sergiy Kolodyazhnyy <1047481448@qq.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE
"""

# Just in case the user runs
# the script with python 2, import
# print function
from __future__ import print_function
import gi
gi.require_version('Gdk', '3.0')
from gi.repository import Gio,Gdk
from time import sleep
import subprocess
import argparse
import signal
import os
import sys

"""Set debug=True to see errors and verbose output"""
debug=False

def gsettings_get(schema,path,key):
    """Get value of gsettings schema"""
    if path is None:
        gsettings = Gio.Settings.new(schema)
    else:
        gsettings = Gio.Settings.new_with_path(schema,path)
    return gsettings.get_value(key)

def run_cmd(cmdlist):
    """ Reusable function for running shell commands"""
    try:
        stdout = subprocess.check_output(cmdlist)
    except subprocess.CalledProcessError:
        if debug: print(">>> subprocess:",cmdlist)
        sys.exit(1)
    else:
        if stdout:
            return stdout

def enumerate_viewports():
    """ generates enumerated dictionary of viewports and their
        indexes, counting left to right """
    schema="org.compiz.core"
    path="/org/compiz/profiles/unity/plugins/core/"
    keys=['hsize','vsize']
    screen = Gdk.Screen.get_default()
    screen_size=[ screen.get_width(),screen.get_height()]
    grid=[ int(str(gsettings_get(schema,path,key))) for key in keys]
    x_vals=[ screen_size[0]*x for x in range(0,grid[0]) ]
    y_vals=[screen_size[1]*x for x in range(0,grid[1]) ]

    viewports=[(x,y)  for y in y_vals for x in x_vals ]

    return {vp:ix for ix,vp in enumerate(viewports,1)}

def get_current_viewport():
    """returns tuple representing current viewport,
       in format (width,height)"""
    vp_string = run_cmd(['xprop', '-root',
                         '-notype', '_NET_DESKTOP_VIEWPORT'])
    vp_list=vp_string.decode().strip().split('=')[1].split(',')
    return tuple( int(i)  for i in vp_list )

def parse_args():
    intro="""
    Runs user-defined command __upon__ entering user-defined set of
    workspaces. For instance
    ./workspace_command_limiter.py -w 1,2,3 -c "python /home/user/some_script.py"
    This is intended to serve only as launcher for a command when user switches
    to their desired workspace, so consider carefully which command you want to use.
    NOTE: This script does run everything from shell, so you are here implicitly trusted
    not to use any command that may break your system. I'm not responsible for your
    stupidity :)
    """
    parser = argparse.ArgumentParser(description=intro)
    parser.add_argument(
           "-w","--workspaces",
           action='store',
           type=str,
           help="coma-separated list(without spaces) of workspaces",
           required=True
           )

    parser.add_argument(
           "-c","--command",
           action='store',
           type=str,
           help="quoted command to be spawned,when switch to workspace occurs",
           required=True
           )
    return parser.parse_args()

def main():
   """ Defines entry point of the program """
   args = parse_args()
   workspaces = [ int(wp) for wp in args.workspaces.split(',') ]
   if debug: print('User requested workspaces:',workspaces)
   pid = None
   proc = None

   while True:
       sleep(0.25)
       viewports_dict=enumerate_viewports()
       current_viewport = get_current_viewport()
       current_vp_number = viewports_dict[current_viewport]
       try:
           if current_vp_number in workspaces:
               if not pid:
                   proc = subprocess.Popen("exec " + args.command,shell=True)
                   pid = proc.pid
                   if debug: print('PID:',pid,'Spawned:',args.command)
           else:
               if pid:
                   if debug: print('killing pid:',pid)
                   proc.terminate()
                   proc = None
                   pid = None
       except:
             if debug: print("Unexpected error:", sys.exc_info()[0])
             if proc:
                proc.terminate()
if __name__ == '__main__':
    main()


Sina's answer in the comments worked for me:

1st run:

$sudo matlab -desktop

this created a .matlab directory in my home folder

$sudo chown -R username:group .matlab

to get the launcher icons and everything else working normally...


How to show unread count on Messaging Menu?

As far as I know this isn't available yet and wouldn't be able to be done without some serious hackery.

May I ask why you would want this? It already indicates that there are new things and you have to click on it to see what needs attention. Having a badge wouldn't really help as it gives no more context than a highlighted mail icon. Also, what happens if you have an unread account with, say, 100+ unread messages? It would be hard to read and not very helpful.

I believe there are mail checker panel applets that have badge functionality, but it's not an aggregate view like the Messaging Menu.


This procedure will eliminate all prior connections in Network Manager on system boot. Please open a terminal and do:

gksudo gedit /etc/rc.local

Use nano or kate or leafpad if you don't have the text editor gedit. Right above exit 0 add the following lines:

rm  /etc/NetworkManager/system-connections/*
service network-manager restart

Proofread carefully, save and close the text editor. All prior connections, passwords, access points, etc. will have been deleted.


Why does Mullvad VPN asks my rootpassword when starting up?

I can not take responsibility for Mullvad but I can tell you that root permissions are required to configure network devices and that is why it might ask for your password. And it should be your password not the root password since Ubuntu usually does have a root password.


Sound card not detected after headphone unplugged

I have used the following command and it worked.
alsactl restore


HP LaserJet AllInOne, scan does not work

The somewhat brute-force answer is that you had installed at some point snmp on your system, and it has not been entirely removed.  The easiest fix for this will be re-installation of snmp:

Open a terminal, and enter the command

sudo apt update
sudo apt install snmp snmp-mibs-downloader

After having fixed the snmp issues, the I/O error 9 referenced by hp-scan seems to indicate tht it may not be fully installed  - see https://bugzilla.redhat.com/show_bug.cgi?id=1347231

To fix this, enter the command

sudo apt install --reinstall hplip


disable updates from command line in Ubuntu 16.04

According to this post
Disable apt-daily.service:
systemctl stop apt-daily.timer
systemctl disable apt-daily.timer
systemctl disable apt-daily.service
systemctl stop apt-daily-upgrade.timer
systemctl disable apt-daily-upgrade.timer
systemctl disable apt-daily-upgrade.service

Or
systemctl disable --now apt-daily{,-upgrade}.{timer,service}

The annoying update notifier can be simply removed by following command:
sudo apt purge update-notifier-common

Further if you want to stop automatic security updates run
sudo apt purge  unattended-upgrades

Ubuntu 20.04

On Ubuntu I had some problem disabling the daily update. The update gets triggered by systemctl which triggers anacron and starts the script /etc/cron.daily/apt-compat. I commented out the last line
# exec /usr/lib/apt/apt.systemd.daily

which stops running the update.

Further I had also to stop the autostart of discovery by doing it the following way:
sudo mkdir /etc/xdg/autostart/disable
sudo mv /etc/xdg/autostart/org.kde.discover.notifier.desktop /etc/xdg/autostart/disable


Can't dual boot Ubuntu, Windows boots directly

Try booting from an Ubuntu USB and installing Boot-Repair. You will need a persistent install for this, I think (haven't tried downloaded Boot-Repair onto a USB before). Try the "Recommended repair" first. If this doesn't work, you will be able to use the app to create a BootInfo summary that you can post here which will make it easier for others to solve your problem.


Steam game does not use all available CPU power

It may not be a problem of CPU, but video card or available RAM size. Actually some games are poorly optimized and even setting the lowest quality may still require a lot of resources. Also, if you have multicore CPU, it might be that game can't utilize more than one (or two) cores - it's a known issue that can't be helped.


I installed ubuntu 18.04 just to find that Ubuntu doesn't have necessary drivers to support the hardware of inspiron 5491. None of the wifi, sound, etc. works.
But manjaro is the best alternative, and I surely recommend to go for it.


Sending a fax via a mobile connected via a USB cable

Most mobile technologies cannot support faxing. The quality of the connection is not good enough to properly transmit fax tones. However, you may consider setting up an account with an online fax provider if you wish to fax from your computer.


I was having this problem. I installed GNAT and GPS on Mac OS from Adacore. I found a directory containing a bunch of Ada related binaries including gcc

/opt/gps/bin

But using either this version of gcc or the default installed on my machine I get the following error

gcc: error trying to exec 'gnat1': execvp: No such file or directory

I had to use the gcc binary located in

/Users/dale/opt/GNAT/2018/bin/

And it works. So I think as someone else commented this may be due to the version of gcc you are using.


What is this screen distortion effect called?

I am having this exact problem, and have been for longer than 11 days; thus I haven't noticed your thread until now. :)  My system only crashes after using Godot engine for a random period of time.
So, for those who hate chasing things:
Here is an extremely-easy-to-do walkthrough of how to add nomodeset to your boot parameters, along with an explanation of why that's a bad idea to do all the time. (Short version: nomodeset just turns off your video drivers entirely. Great for getting in to your system to download & install the right drivers; lousy for regular use where you wanna have 2 monitors &c.)
As per the suggestion above I will try to download the proprietary version of the drivers, although...it was supposed to ship with stable ones to begin with!
Edit:  Following this guide, I tried the PPA third-party repository.  They don't work, either.
If I plug my monitors into my motherboard, things work okay, but...I don't get to use my video card. :( Things aren't as fast as they ought to be, &c.
I cannot figure this problem out. It makes me sad.


How do I create a launcher item to show all open applications?

U can replicate Super+W using Ubuntu Tweak.. This method doesn't give u a Launcher Item but its something easier, this is how its done.

Download it from here and Install it http://ubuntu-tweak.com/

Run it, Go to the Tweaks Tab.

Go to Compiz Settings. Do what's shown in the image to customize Ur workspace edges.

Everytime u touch the bottom right corner all ur active windows are displayed and u can switch among them easily.


Take the default Polish layout (the one with the name Polish, with no further specification). This is the programmers layout.

EDIT: Alternatively, you can always do setxkbmap -layout pl -variant basic or just setxkbmap -layout pl, but that will not be kept across sessions.

Both XFCE and the default Unity shell use the same layouts, just with different interfaces. I guess the reason that XDE uses a tree structure is that all the different variants of the Polish layout are defined in the same file, /usr/share/X11/xkb/symbols/pl. By the way, it is a simple text file; creating your own layout is not hard.


qtfm: error while loading shared libraries:

You are using a 32-bit program on a 64-bit install, and missing the 32-bit libraries needed to run the program. The failure is due to the program needing the 32-bit version, and the 64-bit version being loaded instead.

You can run sudo apt-get install libmagic1:i386 (in 12.10 or newer) to install the 32-bit version, which should hopefully resolve the issue. On 12.04, you will have to be running the 32-bit version to use the 32-bit version of qtfm. On 64-bit you will have to use a 64-bit build of the application, either pre-built, or installing from source.


You can install the 4.10 kernel by running in terminal

sudo apt install linux-generic-hwe-16.04

This will install the HWE rolling kernel that is used when you do a fresh install from a 16.04.3 ISO.

Regarding new X stack including mesa drivers, you can install them by

sudo apt install xserver-xorg-hwe-16.04


How to show listening ports and TCP connections to the ports

Try

netstat --tcp --listen --numeric-ports

Ex.

$ netstat --tcp --listen --numeric-ports
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN
tcp        0      0 127.0.0.1:6010          0.0.0.0:*               LISTEN
tcp        0      0 127.0.1.1:53            0.0.0.0:*               LISTEN
tcp6       0      0 :::22                   :::*                    LISTEN
tcp6       0      0 ::1:631                 :::*                    LISTEN
tcp6       0      0 ::1:6010                :::*                    LISTEN

and

netstat --tcp --numeric-ports

Ex.

$ netstat --tcp --numeric-ports
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0    272 192.168.1.11:22         192.168.1.3:43444       ESTABLISHED
tcp        0      0 192.168.1.11:22         192.168.1.2:65370       ESTABLISHED
tcp        0      0 192.168.1.11:22         192.168.1.2:65369       ESTABLISHED


How do I configure the default emoji font to be used in OS/Browser? (it's currently Symbola but I want Noto)

One way to set Noto Emoji as the default emoji font in Ubuntu is to setup some local font config files.

Create the directory and the file itself with:

mkdir -p ~/.config/fontconfig/
touch ~/.config/fontconfig/fonts.conf

And then populate the created file with the following text:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">

<fontconfig>
  <match>
    <test name="family"><string>sans-serif</string></test>
    <edit name="family" mode="prepend" binding="strong">
      <string>Noto Emoji</string>
    </edit>
  </match>
  <match>
    <test name="family"><string>serif</string></test>
    <edit name="family" mode="prepend" binding="strong">
      <string>Noto Emoji</string>
    </edit>
  </match>
  <match>
    <test name="family"><string>monospace</string></test>
    <edit name="family" mode="prepend" binding="strong">
      <string>Noto Emoji</string>
    </edit>
  </match>
  <match>
    <test name="family"><string>Apple Color Emoji</string></test>
    <edit name="family" mode="prepend" binding="strong">
      <string>Noto Emoji</string>
    </edit>
  </match>
</fontconfig>

And finally flush the font cache: fc-cache -f -v.

If Noto is installed you should now see Noto for emoji unicode blocks in the browser for example, and Symbola filling in where Noto is lacking.


The / character is used to separate the different directories, and it fails because the directory 2017 does not yet exist. To create nested directories with the parent directories created automatically, use

mkdir -p 2017/October/10


The upgrade to Gnome 3 for Natty involves updating much of the GTK libraries - and as the forums (and AskUbuntu) have shown, some applications no longer work or had to be manually worked-around.

The core Gnome apps upgraded by the PPA does work fine - now - certainly didnt in the early days of the PPA. Thus the IDE, banshee, firefox etc works ok.

The PPA is a testing PPA.  If you are worried by data loss - backup with a full disk image.

Oneiric is less than two weeks away - my strong recommendation is wait until then.  When the upgrade is available, disk-image your system,  ppa-purge all PPAs and then upgrade.


The problem is because your folder is owned by root, instead of ftpuser.

To fix it run:

sudo chown -R ftpuser:nogroup /var/www/ftuuserfolder


suspend doesn't work on Dell Inspiron 1525

The line

PM: Device 6-2 failed to suspend: error -5

suggests that there is a problem with suspending with that device. You can find out what is on Bus 6.2 by doing lsusb and looking at that.
If the problem persists, file a bug report with "ubuntu-bug linux"


Command to bring up a list of GNOME shell shortcuts?


Where can I find this graphics file from the installer?

I took these files

and made this image that looks CLOSE to the one in your picture, but not exactly. unfortunately, I couldn't find the exact one you have. I hope fits your needs.


SSH is a protocol for secure communication over an insecure network while sshd provides a daemon which responds to incoming SSH requests.
When you specify a port in ssh use the -p flag. So, for example:
ssh -p22 user@ipaddress

NOT
ssh user@ipaddress:22

Your IP address would be something like 192.168.x.x not 0.0.0.0 As @steeldriver pointed out in the comments, "0.0.0.0 is just shorthand for 'all IPv4 interfaces'. It's not a real address that you should use in a ssh command".


apt-get works with --force-yes but cannot reproduce the issue on a fresh box

Try this on your server (or use sudo for desktops):

apt-key net-update
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 437D05B5
apt-get update
apt-get install ntp=1:4.2.6.p3+dfsg-1ubuntu3.1

The two apt-key commands will refresh the key. If you want to iterate over all your apt-key keys:

sudo apt-key adv --keyserver keyserver.ubuntu.com --verbose --refresh-keys

You should always apt-get update before you apt-get install some-package.

I think the basic problem is that you haven't used apt-get update for a while, the key got old probably and had to be checked/refreshed (I'm not 100% sure though).


Executable not running even after chmod'ing it

I had the same problem on my 64-bit machine when I downloaded file for 32-bit platform.
Unfortunately you don´t see any error message if you try to execute such a file.

Check your file type using file command e.g.:

32-bit

N56VZ:~$ file /opt/eclipse/eclipse
eclipse: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV),
dynamically linked (uses shared libs), for GNU/Linux 2.2.5, not stripped

64-bit

N56VZ:~$ file /opt/eclipse/eclipse
eclipse: ELF 64-bit LSB executable, x86-64, version 1 (SYSV),
dynamically linked (uses shared libs), for GNU/Linux 2.4.0, not stripped


Can I use the Adwaita theme in Unity without installing GNOME shell?

You can try running sudo apt-get install gnome-themes-standard, or you can just click this button:

Or you can download this .deb which contains the theme also link


Lubuntu 16.04 fresh install stuck on boot

Well, the complete answer is that:

Add temporarily the nomodeset boot option (from the grub boot menu without editing the /etc/default/grub file yet) as described here: How do I set 'nomodeset' after I've already installed Ubuntu?
After you login try run the commands sudo apt-get update and sudo apt-get dist-upgrade and reboot (the nomodeset option was just temporary) and see if it was a bug which got fixed with the update (you could also run this from the rocovery mode before trying nomodeset).
I it wasn't fixed you can try again with nomodeset option and after you login go to Software & Updates and under the Additional Drivers tab see if there is any proprietary gpu driver and install it. (also intel-microcode is good to have if it's available but has nothing to do with this problem). It is important to remember which package it installs (if it isn't obvious from the name then google it) in order to be able to remove it from recovery mode if your system doesn't boot afterwards. Reboot to see if it got fixed. If it doesn't work then remove it.
If step 2 and 3 doesn't work then set nomodeset at /etc/default/grub file as described at the first link to make it permanent. Don't forget to run sudo update-grub afterwards.


How to roll-back a shell command once executed?

There is no way to "roll back" shell commands.

If you removed a file using rm command, you can only try to restore it using testdisk or a similar software.

Some of shell commands can be rolled back by other shell commands.

For example, if file.txt did not exist, command

echo "bla bla bla" > file.txt

can be rolled back by

rm file.txt

If file.txt had some content, the first command can't be rolled back.

So you need to be very careful using shell commands!


notify-send (alert) not popping-up GUI bubble messages

Aliases are automatically created in ~/.bashrc
When you look in ~/.bashrc you see these lines:
# Add an "alert" alias for long running commands.  Use like so:
#   sleep 10; alert
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

The problem with the code is the --urgency=low flag. Sometimes the message pops up, some times it doesn't. After all it is low priority right?
To make the message always appear set the urgency to critical. Rather than changing the system default I created a new line for my own purposes:
# Add a "redalert" alias to pop-up on GUI desktop screens.  Use like so:
#   redalert "Weather update: It's raining Red States"
alias redalert='notify-send --urgency=critical -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'

Now you can use:
redalert "Weather Update: It's raining Red States"

and it works perfectly!


How do I get Ubuntu / Nvidia GeForce 8400GS to correctly recognize two identical monitors?

Double check that they are actually identical. Look at the product ID and dates and similar things. I had a case at work where two monitors we thought were identical didn't support identical sets of resolutions, and I discovered that they weren't identical. One was a slightly modified version released a couple months later. They had the same model number and had been sold as if they were the same product, but were not.
Get your hands on an actual DVI cable. Sometimes adapters do funny things. You say it's a "proper adapter." I have no idea what that means (what's an improper adapter?). I do know that I've used adapters which were supposed to convert one cable to another type and did not, whereas the system worked fine with the correct cable. DVI cables shouldn't be expensive. Where I live, you can often find them being thrown away by people moving to HDMI and DP, although that may not be relevant to you.
Try switching the ports the two monitors are plugged into. Presumably, you expect the problem to occur on whichever monitor is plugged into the DVI, but maybe that monitor is broken or something.


From Ubuntu

USB installation Guide from Ubuntu

There's a package called usb-creator-gtk (and usb-creator-kde for KDE-desktop).
It can be found in the Unity Dash
This application has a GUI to copy an iso/or from cd to a USB-drive and make it bootable.

From Windows

You can use the software LinuxLive to create a Bootable USB in Windows.


KDE Konsole has Ctrl-C remapped to new tab

I experienced the same frustrating behaviour.  While poking around I found that I had a profile mapped to a key combination that included Ctrl+C.

If you haven't already, you might want to check your profile short-cuts under Settings -> Manage Profiles.


Windows 10 not detected on installation of Ubuntu on a second SSD

Thanks for this reply. I managed to set most of the parameters you mentionned in the BIOS, but the situation is still the same.
By the way, I forgot to mention that neither Windows is detected nor the Windows disk itself !  Ubuntu only sees the small empty drive. This is probably the reason why Windows is not detected either.
I do not know if it has any effect, by I noticed that, when I display the disks list in Windows, the first disk (No 0) is the empty one on which I want to install Ubuntu, and the second disk (No 1) is the main disk on which Windows is installed.
This seems not disturbing Windows boot, that finds the right disk, but can it be a problem for Ubuntu ?