Is it possible to adjust the snap feature?

This feature is controlled by the Grid plugin of Compiz. I have seen no way to adjust the size of windows when the snap feature resizes your windows though.

You can use CompizConfig Settings Manager  (also known as ccsm) to alter its settings.


Policy Routing - host sending ARP requests for non-local networks

Your ping attempt is binding to the interface (by specifying -I eth0.20) - not the address, and there is no interface route.

If you add an output-interface rule to use the vlan20 table, it will use the next-hop gateway instead of attempting to make an ARP request. i.e.

ip rule add oif eth0.20 lookup vlan20

You will find a rather long explanation, and examples of this occurring in my other answer found here: https://stackoverflow.com/a/47613538/471825


Where do ltsp user accounts need to reside?

I'm not expert in LTSP thing, but since this question didn't get any answers I decided to write what I found out so far...

LTSP accounts should NOT exist in the ltsp image. They can be there, but this is not the correct way of setting up LTSP since you don't want to rebuild your image every time you add new user or change user password.

So, LTSP accounts should be on the server and whenever you login from LTSP client, you will see server account is automatically copied to client's /etc/passwd file

As to other questions you asked, I'm not sure myself.. Just learning this subject...

I'm struggling with LTSP authentication as well. Authentication works, but I can't enforce password policies.


The plugin to run Java in a browser is called IcedTea. Currently, IcedTea only has Java 7 releases (the version 2 releases). Java 8 would correspond to a version 3 release, so until there's a version 3 release of IcedTea, you won't be able to run Java 8 in the browser.


Unity and KDE desktop on the same screen

While I totally don't know why one would want this, it's certainly possible. From a standard Ubuntu (with Unity) installation:

Install kubuntu-desktop
In a terminal within the Unity desktop, try to run the KDE desktop like this:

nohup plasma-desktop &

The nohup somecommand & pattern makes it run in the background and independent of the terminal you're running this in. (specifically, the process spawned isn't a child of terminal in the process tree, but given to the mother of all processes - init.)
optional If you like this and you want to make it permanent you can create a startup script:

Create a text file (with for example Gedit) startkde.sh, containing

#!/bin/bash
# sleep seems necessary - getting kdeinit I/O errors otherwise
sleep 3 && /usr/bin/nohup /usr/bin/plasma-desktop &

Make the file executable, from Nautilus (file properties), or by running chmod +x startkde.sh
Open Startup Applications from the Dash.
Add an entry "KDE" and browse to the script.


Why don't changes in my alsamixer equalizer have any effect?

You likely are using the wrong output device (often happens on my notebook after removing the hdmi-cable).
Enter pavucontrol (commonly pre-installed) in the terminal and you will find selectionbars to change the device.


The simple solution is to execute git clone command in your /home directory, in a location which is owned by you.

e.g. in a sub-folder dev-projects in your /home/username folder.

If from some reasons, the content of the git repository should be located in /opt/lampp/project-sbc then you should execute the git clone command as root, using the sudo command:

sudo git ...... (your git command)

Also as mentioned in the comment:

The user can change the owner of the folder from root to himself.

sudo chown username /opt/lampp

Follow with git command in that folder

git clone .....


How to run a Python script not as '~$ python myscript.py' but as a single command '~$ myscript'?

First, make sure myscript.py is executable by doing chmod +x myscript.py. Second, ensure that the shebang #!/usr/bin/env python appears as the first line of myscript.py. You then execute the script using ./myscript.py [arguments].


How to set default time for QML DatePicker?

You can use a simple JavaScript Date Object to set a default value:

import QtQuick 2.0
import Ubuntu.Components 0.1
import Ubuntu.Components.Pickers 0.1

DatePicker {
    id: timePicker
    mode: "Hours|Minutes"
    date: new Date(0,0,0,8,5)
}

The Date object is used to work with dates and times.

Date objects are created with new Date().

There are four ways of instantiating a date:

var d = new Date();
var d = new Date(milliseconds);
var d = new Date(dateString);
var d = new Date(year, month, day, hours, minutes, seconds, milliseconds);


What will happen to Ubuntu GNOME flavour users after Gnome becomes the new official flavour in 17.10?

The future of Ubuntu GNOME according to the developers:

  As announced last week by Ubuntu founder Mark Shuttleworth, Ubuntu 18.04 LTS will include GNOME instead of Unity. Specifically, it will be GNOME (including gnome-shell) with minimal Ubuntu customization. Next year, if you are using either Ubuntu 16.04 LTS or Ubuntu GNOME 16.04 LTS, you will be prompted to upgrade to Ubuntu 18.04 LTS. For normal release users, this upgrade should happen with the release of 17.10.

Looks like there would be a separate Ubuntu GNOME 17.10 image. In the daily builds there is one.

Update

It's now written

  The latest Long Term Support release is Ubuntu GNOME 16.04.3.

  The final stable non-LTS release is Ubuntu GNOME 17.04.

(emphasis mine) on Ubuntu GNOME's homepage. Also the daily build linked above is gone. Probably the developers decided not to go on with a separate Ubuntu GNOME 17.10 and pulled out the daily build.


I had exactly the same issue with my TV on second HDMI port of my Intel HD integrated graphics on Ubuntu 14.04 even 16.04.

Sometimes TV got detected, sometimes not. It was absolutely same under Windows where helped to disable graphic adapter in device manager for a while and re-enable it and TV on second HDMI got magically detected.

Finally I found a solution also for linux. Trouble is that HDMI port is not enabled and therefore TV/monitor not detected. Normally HDMI port should detect new hardware and enable itself automatically but unfortunately on my hardware this was not happening.

So solution is to enable HDMI port manually on boot. Eg. you have

/sys/class/drm/card0-HDMI-A-1/enabled   disabled
/sys/class/drm/card0-HDMI-A-2/enabled   disabled

So if you in grub during boot add these parameters to kernel

video=HDMI-A-1:e video=HDMI-A-2:e

It should according to http://distro.ibiblio.org/fatdog/web/faqs/boot-options.html enable both ports.

Afterwards just look which port is really used and edit /etc/default/grub with

GRUB_CMDLINE_LINUX_DEFAULT= ...keep options and add... video=HDMI-A...

Just run

update-grub

and it should works.

Eg. on my machine I have 3 HDMI ports but just 2 of them are connected on mainboard (one cannot be connected at all). If I enable all 3 connectors maximum resolution is 1024x768 so I needed to find out used two (in my case HDMI-A-2 and HDMI-A-3 where HDMI-A-3 was first one and HDMI-A-1 was disconnected from mainboard) and enable in grub only just these two, e.g. in my case boot line looks like this video=HDMI-A-2:e video=HDMI-A-3:e.

Currently I use Gigabyte Z87N-Wifi mainboard with one monitor on HDMI and TV on HDMI. With these settings TV get always detected after reboot.


How to fix error "Xlib: extension "NV-GLX" missing on display"?

This error occurs when you install the proprietary nvidia driver on NVidia Optimus laptop. The nvidia card cannot directly be used due to the Optimus design. To repair this, uninstall the nvidia-current package and re-login. After that, you'll solely be running off the Intel graphics card which renders the nvidia card unused though it'll still be using power. Bumblebee allows you to switch off the card, see Is a NVIDIA GeForce with Optimus Technology supported by Ubuntu?


How to use timeshift effectively on Ubuntu?

Full File System Snaphots including OS, Media and installed staff: Settings -> Users and switch radio-button under Include All; Settings -> Filters remove all filters.
Go to Settings -> Users Tab and switch radio-button under Include All then go Settings -> Filters and add patterns to exclude all another dirs from your File System.
, 4. Go to Settings -> Filters Tab and use needed patterns to exclude unnecessary staff.


nVidia Settings: Overriding anti-aliasing causes delay

Change your shortcut to this:

env vblank_mode=0 WINEPREFIX="<prefix>" wine SketchUp.exe

Your just adding vblank_mode=0 between env and WINEPREFIX


This answer is based on comments on the original question

Typically one wouldn't need to concern themselves with their own lo traffic.

As you said, you have a network monitor graph applet.  If your applet can't distinguish between interfaces its not doing its job, really.

Based on what I can see, nut is used to communicate with your UPS.  That's what the increased communication is.  If you don't want this increased local-system traffic, then don't have your UPS communicating with the computer.  That may reduce the networking traffic.


However unless i put the full file path into the --link-dest path it shows the message
--link-dest arg does not exist:

Thats actually good. The --link-dir option works, the path exists.
'cat /media/backup/$USER/lastbackup.log'

is the problem. The expression just isn't evaluated.
You might want to try
`cat /media/backup/$USER/lastbackup.log`

or
( cat /media/backup/$USER/lastbackup.log )


I installed League of Legends and I can't open it in Wine

Every Application that can be used in Wine usually has an entry in the WineHQ AppDB.  In your case, the main AppPage is WineHQ - League of Legends.  You always want to see if there are any Installation instructions available.  As you can see there are instructions for this entry.


I found the solution in this comment. Basically I just had to manually download the file ippicv_linux_20151201.tgz (from here) and move the zip file to the correct location (/home/ao/opt/opencv/3rdparty/ippicv/downloads/linux-808b791a6eac9ed78d32a7666804320e/).

Then it could compile :)


12.04 Ubuntu studio PREEMPT_RT kernel options

I've entirely given up on using ubuntustudio for audio processing and gone to Planet CCRMA.

I do however want to give some resources for those looking for preempt-rt kernel config options. Planet CCRMA maintains a fairy recent kernel with a full prempt_rt patch. You can extract the config files from the rpms found here for x86_64:

http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetcore/17/x86_64/repoview/SystemEnvironment.Kernel.group.html


You are in this case:

chcon -R --reference=RFILE FILE

where:

chcon - change file security context; you can check any security context of a file with ls -Z.
-R - operate on files and directories recursively.
--reference=RFILE - use  RFILE's  security  context rather than specifying a CONTEXT value.

So, the above command change recursively the security context of each file from /var/www/html/install to those from /var/www/html.

Type info coreutils 'chcon invocation' in terminal and  you will have access to the complete manual.

This manual can helps you to understand everything about Security-Enhanced Linux (SELinux).


How to lock down connecting to a specific WiFi

1) How can I disable the WiFi card on the motherboard?

To me that would be from BIOS. On-board devices should have an option to disable them.

  2) How can I set my USB wireless to connect using only a specific connection?

Connections are only established with connection you provide a password for. If the guest network is strong and known it probably will pick this up. Dropping the password for it might be an option where you will need to manually input the password when you want to connect to it (and not safe the password).

Here is a method of disabling network manager for a specific MAC address: How can I make NetworkManager ignore my wireless card? You should be able to use this to make the guest network "un-managed" so Network Manager ignores it (another one about this).


Cannot install package subversion from deb file

You can try gdebi. gdebi will install a .deb package resolving all it dependencies i.e. it will install the package along with all dependencies from a .deb file provided that the dependencies are satisfiable by packages from the repositories mentioned in the source lists. First install it:

sudo apt-get install gdebi

Now for your .deb file, from the downloaded directory run:

sudo gdebi subversion_1.7.9-1+WANdisco_i386.deb

This will install the package satisfying all dependencies.

If you want to explore more, gdebi also has a nice feature that will give you a apt-get install compatible line from the .deb file containing all dependencies:

sudo gdebi --apt-line subversion_1.7.9-1+WANdisco_i386.deb

Check man gdebi for more info.

Need to mention that, you can also just run xdg-open pacakge.deb to open it via the software center that will do all the tasks gdebi would do i.e. software center will install the pacakge satisfying all the dependencies. (Thanks "muru" for the info).


Can I access my broken machine data in any way possible?

i386 is 32-bit, amd64 is 64-bit, it has nothing to do with the CPU manufacturer.
 You needed to enable multiarch and add the i386 architecture in order to install the 32-bit libraries.

since 32-bit and 64-bit libraries often conflict, you likely removed the 64-bit version of the libraries you installed. Mesa is your graphics library.

try booting in recovery mode and see if you can get a command prompt to reverse the changes you made.


USB Midi Keyboard causes ALSA Port Unsubscribed

I'd guess that due to some electrical error on the bus, the PC thinks that the keyboard has disconnected. This is probably caused by the keyboard using more power than the port (hub) can supply.


When a NET SEND style message is sent to a system running Samba, it will run the command specified in the message command configuration.  According to the smb.conf man page, messages will be rejected by default, which might explain what you're seeing:

  If you don´t have a message command then the message won´t be
  delivered and Samba will tell the sender there was an error.
  Unfortunately WfWg totally ignores the error code and carries on
  regardless, saying that the message was delivered.

One program that can take these messages from Samba and display them on the desktop is LinPopup:

http://linpopup2.sourceforge.net/

I haven't tried it personally, and it doesn't appear to be packaged for Ubuntu, so you would probably have to build it from source.


How do I add my Samsung laptop's volume keys?

Try this.

Usage:

/usr/bin/pulseaudio-ctl mute      #     will toggle status of mute

/usr/bin/pulseaudio-ctl up        #     will increase vol by 5 %

/usr/bin/pulseaudio-ctl down      #     will decrease vol by 5 %


Which graphics driver should I use on an Asus N43?

Now also available as PPA:

To remove the old script/git version

sudo bumblebee-uninstall
sudo apt-get install ppa-purge
sudo ppa-purge ppa:ubuntu-x-swat/x-updates

To install the PPA version

sudo apt-add-repository ppa:mj-casalogic/bumblebee
sudo apt-get update
sudo apt-get install bumblebee


How to execute a script from trusted shell

To execute a script you've downloaded as a file, you'll want to ./ebash instead of ebash. What this does is it executes from the current directory (./) the file named ebash.

Typing in ebash looks for that command to be installed in /bin or another place and would not look to execute files in external directories.


How to decrease space between indicators in GNOME Shell?

As with some Gnome extensions, installing doesn't work if the extension says it does not support that version of Gnome - even if it does work. So to install it:

Download the extension from the extension homepage:https://bitbucket.org/mathematicalcoffee/status-area-horizontal-spacing-gnome-shell-extension/downloads/gnome3.8_status-area-horizontal-spacing@mathematical.coffee.gmail.com.zip
Extract the status-area-horizontal-spacing@mathematical.coffee.gmail.com folder to ~/.local/share/gnome-shell/extensions/status-area-horizontal-spacing@mathematical.coffee.gmail.com/
Run gedit ~/.local/share/gnome-shell/extensions/status-area-horizontal-spacing@mathematical.coffee.gmail.com/metadata.json, and edit the shell-version to include 3.10:

   "shell-version": [
    "3.4",
    "3.6",
    "3.8",
    "3.10"
  ],

Enable the extension from Gnome Tweak Tool. This method works with quite alot of extensions, but does not always work. You may need to restart the shell with Alt+F2+r

You can also modify the theme to have a different spacing - this can be done by finding the theme's directory (e.g. /usr/share/themes/ZukitwoGreen/gnome-shell, ~/.local/share/themes/ZukitwoGreen/gnome-shell), and editing the gnome-shell.css file to have a different hpadding (you can use find and replace) - e.g. mine is:

-natural-hpadding: 4px;
-minimum-hpadding: 4px;

I think this is also available as a option under the 'Elegance colours' customizable theme.


Unless the script requires it be in a particular location, you don't "install" a shell script, you just save it where you want it, and run it. It would also be advisable to read through the script first (by opening it in a text editor like Gedit) to make sure the script is safe.

Ways To Run A Shell Script

1. Execute Script In A Specific Subshell

In this approach you specify which shell to run, and the path to the script you want that shell to run. Since you are executing a shell, and telling it which file to run, the script doesn't need execution permissions, which is nice from a security standpoint. Your default shell may be aware of where the shell you're running is located, in which case you won't need to specify the shell's path. Unless there are spaces in the file/folder names you don't need to wrap the shell path or script path in quotations. Some shells may not accept just a file path, they may require specific options, and formatting, but the idea is the same.

 "/path/to/shell" "/path/to/script"

Examples:

"/bin/sh" "/home/user1/Downloads/script.sh"

bash /home/user1/Downloads/script

2. Execute Script In Current Shell

In this approach you use your currently running shell, and the path to the script you want that shell to run. Since you are executing the script directly, the script needs execution permissions. Unless there are spaces in the file/folder names you don't need to wrap script path in quotations.

chmod u+x,g+x,o+x "/path/to/file.sh"

"./path/to/file.sh"

Examples:

chmod u+x "/home/user1/Downloads/script.sh"

 "./home/user1/Downloads/script.sh"

Some things to keep in mind with this approach are that you may want to limit who can run the script. "u+x" gives the owner of the file permission to run it, "g+x" gives members of the group it's owned by to run it, and "o+x" gives everyone permissions to run it. The script will only work if it's compatible with the shell you are running. You only need to chmod the script once; in future you can proceed to the second command. You will only be able to chmod the script file if you have permission to edit that file. If you are not the owner of the script file, and do not have permission to chmod it, you can use Sudo to gain elevated permissions.

Examples:

sudo chmod u+x,g+x,o+x "/home/user1/Downloads/script.sh"

 "./home/user1/Downloads/script.sh"


How to recover GRUB after upgrade from 9.10 to 10.04?

You can try to restore GRUB2 by following these detailed instructions.


What is the best file system on top of LVM encryption?

dm-crypt doesn't depend on LVM. It can encrypt any block device, like CDs, even swap space.

It supports a bunch of modes of operation, some of which impact performance more than others, and all of which interact differently with the file system. The encryption doesn't necessarily operate using the same block size as the device itself: the XEX-TCB-CTS mode of operation (XTS) deliberately uses blocks that are not evenly divisible by the hardware block sizes, for example.

However, in reality, the overhead from the encryption is so large that it doesn't make any difference at all. I therefore recommend you choose your file system based on reliability considerations.

As maaartinus points out, if your CPU supports the AES-NI instruction set (cat /proc/cpuinfo to find out), encryption will be fast enough that it may make sense to test different filesystems. However the differences between various filesystems should still be comparable to using no encryption at all, and the usual advice would hold. I still recommend to choose a file system based on considerations of reliability, not speed.


How can I specify the Jupyter notebook running path?

which jupyter-notebook

Tells me where my jupyter is installed, in my case it's:

/home/ravexina/.local/bin/jupyter-notebook

Which version of python it's using?

Let's run jupyter notebook:

jupyter notebook

You can also run it using:

jupyter-notebook

then we can use pgrep to detect which python version is being used by jupyter:

pgrep -a jupyter

Mine is python3:

3700 /usr/bin/python3 /home/ravexina/.local/bin/jupyter-notebook

What about screenshot

In your screenshot, what I can see is that your jupyter is using python2 and is running a python3 kernel, which means you are working with a python3 file however your work is being done by jupyter using python2.

You might have both versions installed. Anyway my jupyter is installed using pip3 and is up to date, its version is: 4.3.0 and it's the last version, what you are referring is ipython 6.0.0.

Anyway, if you don't have pip3 install it:

sudo apt install python3-pip

then update it:

pip3 install pip --user --upgrade

after that install/upgrade jupyter:

pip3 install jupyter --user --upgrade

Now you have last version of jupyter and ipython 6.0.0 as its dependency installed.


gksu doesn't show the installed program folders into wine folder

First you really should not be running wine as root, it is a security risk to do so, see Is installing wine in Ubuntu safe? and Risks/Disadvantages associated with Wine and links.

Therefore, ~/.wine should be owned by your user and you can modify file in ~/.wine without running as root or using gksu

Second , gksu is depreciated, see When to use pkexec vs. gksu/gksudo? and What is the difference between "gksudo nautilus" and "sudo nautilus"? for some discussion.

The "problem" you are having is that gksu is setting $HOME as /root and thus you are editing /root/.wine rather then your /home/$USER/.wine .

The above links review this as does https://help.ubuntu.com/community/RootSudo, specifically https://help.ubuntu.com/community/RootSudo#Special_notes_on_sudo_and_shells

See also What is the difference between gksudo and gksu?


How well is the thinkpad internal microphone supported?(x230)

If it's supported, it should be an input mode selectable in pavucontrol (both package to install and the command to run) in the tab "Input Devices" or "Configuration". Check that out using the most recent version of Ubuntu.

Example screen:

Alternatively, find more of these 'switches' in alsamixer (run in the terminal).


What are the steps to take after a successful openstack install using juju openstack-base charm bundle?

You'll need to download and extract the bundle zip file using this link - the novarc and helper tools are co-located with the bundle in the charm store.


sudo apt update always giving Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)

I had the same issue.  It turns out that apt-get uses /etc/apt/apt.conf for the proxy settings (my browser settings are already set).
Making apt.conf match my browser proxy settings solved the problem.

/etc/apt$ cat apt.conf

Acquire::http::proxy "http://<proxy>";
Acquire::https::proxy "https://<proxy>";
Acquire::ftp::proxy "ftp://<proxy>";
Acquire::socks::proxy "socks:<proxy>";


I think I understand what you are asking.
Do you mean that some of your downloads come with a changelog?

A changelog to me is a log of changes along with other details like who made the change, what changes were made, and its purpose. I see it often as text files in software downloads, and on websites that host OSes and softwares.

Here are some examples of a changelog.
(I understand better by example, so I'll explain this way.)

Example 1

For example, take a look here for the changelog of the Linux Kernel.

Linux Kernel Changelog

You see a list of the changes that were applied to the Kernel from its previous release.

-

Example 2

Here's another changelog for comparison.

Raspberry Pi Changelog

See how the format is very different. Here, the file is called Changes.

Also, a changelog is sometimes embedded into a compiled program and is accessible via the interface. There's no specific standard for formatting of the text, and can be referred to as different names. (Changes, Changelog, Updates, etc.)

I hope that answers your question. If not, please elaborate.


Android Emulator output not forwarded thru SSH X11 forwarding

I worked around this using VNC:

On myserver side:

cd $ANDROID_SDK/emulator
vncserver :2 -localhost no -geometry 540x760
export DISPLAY=:2
./emulator -avd Pixel3

On client side:

vncviewer myserver:5902

While I'd prefer to have a flawless UI integration this catches the android emulator screen without problem so that it's usable. I still hope to find options enabling direct X11 forwarding.


Problem with mp3 tags using youtube-dl and id3v2

youtube-dl actually downloads both video and audio even when you specify --extract-audio so your syntax has confused youtube-dl and FFmpeg by giving the same filename for both streams.

Perhaps the easiest fix (and there are a few other ways to accomplish your goal) is to change your youtube-dl syntax to the following:

youtube-dl --extract-audio --audio-format mp3 \
          "https://youtu.be/Sqk3B2041uk" --output "test.%(ext)s"

And certainly on my own system this successfully created a file that id3v2 can then process:

andrew@ilium~/tmp$ youtube-dl --extract-audio --audio-format mp3 \
>           "https://youtu.be/Sqk3B2041uk" --output "test.%(ext)s"
[youtube] Sqk3B2041uk: Downloading webpage
[youtube] Sqk3B2041uk: Downloading video info webpage
[download] Destination: test.webm
[download] 100% of 2.07MiB in 00:02
[ffmpeg] Destination: test.mp3
Deleting original file test.webm (pass -k to keep)
andrew@ilium~/tmp$

Note that by default youtube-dl downloads the best quality audio and video available, hence for this particular clip there is Opus audio and VP9 video in a webm container. FFmpeg then removes the video and converts the audio as ordered, have a look at the --keep-video option to see the magic at work :)


Recover HDD after creating USB installer

First don't use the drive to install or transfer any data onto there.

Run testdisk and follow the instructions to recover your partition


Problems after upgrading to 12.04 - black screen after log in!

what kind of VGA drivers you got ?

from the grub menu at start up choose recovery mode and from that choose failsafeX mode from there install the VGA drivers .


Dell Latitude 3340 two-finger touchpad functions not working

Some touchpads simply do not support this.  I have an HP DV9000 which is otherwise identical to a friend's DV9000 but their touchpads have different part numbers and only one of them supports two finger control.  Simply put, if two finger scrolling is not supported in the mouse/touchpad area of the System Settings, then you have a laptop with a single-finger touchpad and there's not much you can do about it except to either plug in an external touchpad (or keyboard with touchpad as I did) or get rid of that laptop and get one with the type of touchpad you like.


How can I get a variable from terminal to use it in my script?

When you invoke a script like

myscript parameter1 parameter2

the parameter1, parameter2 etc. values from the command line are available inside the script as positional parameters $0, $1, ... etc

parameter $0 contains the name by which the script was invoked (myscript)
parameter $1 contains the value parameter1
parameter $2 contains the value parameter2
and so on

So in your case if you want to run your script like

inst program

to install program, then inside the script you can write

apt-get install "$1"

See for example Handling positional parameters at http://wiki.bash-hackers.org


Their official website has this to say about this printer and Linux:

Argox Linux Printer Driver V1.3.0(64-bit) (will download a zip)
Ubuntu 11.10 ~ 16.04, Fedora 16 ~ 24, openSUSE 11.4 ~ 42.1, Red Hat Enterprise Linux Server 7.2, NeoKylin 6, Red Flag Linux 6, CUPS printing system for Linux (1.5 ~ 2.1.4)"

Looks like full CUPS support so this should be fairly straightforward and the printer should work perfectly after installing the zip (There is an an "install" script that needs to be executed that sets the .PPD up and restarts cups for you).


It might be possible to re-format the entire disk, provided no physical damage was done when you wiped it.

First start up the installer and see if you can create a new partition table. If this works you can continue to install as normal.

With regards to your question about installing to a single partition, yes you can. You will need to create a swap file instead of dedicating a partition. Read the Swap FAQ here


Update it to the latest version with
sudo youtube-dl --update

and then try again.
Edit: Since you wrote you installed it with a package manager and thus you can't update it so easily, for this particular software I'd recommend to install it from its upstream site https://youtube-dl.org/ to your /usr/local/bin directory and use it from there; then you can update it whenever needed (which is often because YouTube often changes some stuff to thwart software like youtube-dl).
You can either have a version from an official repo which is always slightly outdated, or a working one. As a general rule of thumb, you need to update it whenever you want to use it.
I just updated it, and it gives me
sh@balrog:~$ youtube-dl --version
2021.04.01


How to resolve Unmet dependencies with libminiupnpc-dev specificly?

Workaround that worked was downgrading:

sudo aptitude install libminiupnpc-dev

I rejected the first option and it automatically searched for another solution. Accepted the next solution which was to downgrade libminiupnpc8 [1.6-precise2 (now, precise) -> 1.6-3ubuntu1 (precise)]


Can't grant myself permissions to execute `rm` command as sudo

Putting your userid in the sudoers file allows you to preface your command with sudo (e.g. sudo rm /root-directory). It does not grant constant root-ness. One does NOT always want to be root.

Read man sudo


How to hide running app icon from gnome panel QML PyQt5

There is apparently no easy way that is exposed to the user. It comes down to assigning the _NET_WM_STATE_SKIP_TASKBAR to the window.

See here on Askubuntu for a few possibilities to externally change the window properties after the window has been created. Using devilspie will systematically hide windows that match certain rules from the taskbar. Specific windows can be hidden from the taskbar using wmctrl. This could for example be done in a wrapper startup script.

The better way is to set the window state from within the code of the application where the window is created. For python, it would come down to a statement such as window.set_property("skip-taskbar-hint", True) for GTK. See here for a few hints: https://stackoverflow.com/questions/22256507/how-to-make-a-program-skip-the-task-bar-task-list-in-gnu-linux.


Searching for anaglyph 3D games and apps

This forum post should help you

http://www.mtbs3d.com/phpBB/viewtopic.php?f=3&t=2939&start=0&hilit=linux


How do I get the first 5 lines of the top command and append to a file?

If you want it to appended periodically - you'll probably need some loop or something else to call that script more than once.
Here's an example with an infinite while loop:

while [ 1 ]; do
    top -b -n 1 | head -n 5 >> test.txt
    sleep 1
done

You can adjust how often it will be logged by changing the parameter of sleep (in seconds).


What is the purpose of canberra-gtk-module?

From the package description of libcanberra-gtk-module:

  translates GTK+ widgets signals to event sounds

GTK+ is a toolkit for creating GUIs, most of the default Ubuntu desktop, and the GNOME desktop environment, is developed using it. libcanberra is a library for playing sounds. libcanberra-gtk-module, then, is the module that takes GUI events from GTK+ (like pressing a button, or minimizing a window) and plays some configured sound.

The error message commonly seen maybe a result of these bugs:

#872172 - libcanberra-gtk0 should recommend Gtk2 and Gtk3 module to fix: Gtk-Message: Failed to load module "canberra-gtk-module"
#888779 - Failed to load module "canberra-gtk-moduleanberra-gtk-module" (sic)
#689434 - Gtk-Message: Failed to load module "canberra-gtk-module": libcanberra-gtk-module.so: cannot open shared object file: No such file or directory


Remove them from the cdrom group (as well as admin/adm/sudo) to restrict the privileges:

deluser username groupname

e.g.

deluser gert cdrom

Then log out and log back in to make it effective.

Note! Make sure to use the second argument to deluser, otherwise it will delete the user.


No Chrome icon in system tray since update to 70

With latest system update the issue gone. As of now I have:

Browser: Google Chrome 71.0.3578.80 (WebKit 537.36)
Operating system: Linux 4.15.0-42-generic #45~16.04.1-Ubuntu SMP Mon Nov 19 13:02:27 UTC
2018 x86_64 x86_64 x86_64 GNU/Linux


Xubuntu20.04 - Xfce4 Panel disappeared, can't add Wifi Icon to new one

I had this problem after updating to Ubuntu 20.04. As the OP mentioned, the solution was to add the Status Notifier Plugin back to the panel.
In my case, however, the plugin was uninstalled at some point, so I had to install it back:
$ sudo apt-get install xfce4-statusnotifier-plugin

Fortunately, after APT was done, I could add it back to my panel.


How to list compression ratio on compression enabled btrfs?

there is third party tool that can do this.

https://github.com/kilobyte/compsize

usage:

ayush@devbox:/code/compsize$ sudo compsize /opt
Processed 54036 files, 42027 regular extents (42028 refs), 27150 inline.
Type       Perc     Disk Usage   Uncompressed Referenced
Data        82%      5.3G         6.4G         6.4G
none       100%      4.3G         4.3G         4.3G
zlib        37%      427M         1.1G         1.1G
lzo         56%      588M         1.0G         1.0G


Ubuntu 16.04 - apt-get update - KEYEXPIRED

I have the exact same issue (I use Arc theme), and this is more of a workaround. Technically this error is not harmful because it only deprives you of updates of the related software (presumably Arc Theme by Horst3180).

Go to Settings > Software & Updates > Other Software and uncheck http://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_16.04 like so (see fifth row):


Can I shrink another drive apart from C to make space for Ubuntu installation?

Yes. You can shrink that 263 GB volume by following this guide. Next you can increase the space of your /home and swap using this guide.


Ubuntu core snappy for rpi2 - source code

Ubuntu Core is directly build from the Ubuntu distribution, just with a different set of packages.

So, what happens during builds is basically a traditional live creation, and removal of the debs and apt metadata in /var/lib.

To get this Ubuntu source code, you can simply refer to Where can I find the source code of Ubuntu? for instance!


Can't login using my login username and password

To recover password you need to follow these steps:

Boot your computer.
When you get the grub menu, select option with recover mode.
This will take you to recovery menu. In recovery menu select option "drop to root shell"
A shell prompt will be displayed at the bottom of the screen with root as username. To change the password of particular user say username type:

passwd username
The above command will ask you to enter your new password and retype password. Type your new password.
You might get "Authentication Manipulation error". If you get this error then you need to type :

mount -rw -o remount /

And again follow step 4 and 5.


Can't install Windows 10 alongside Ubuntu 16.04 due to redundant partition flags

You reported this Windows error message (translated from German):

  It was noticed, that the EFI-systempartition was not formatted as NTFS. Please format the EFI-systempartition as FAT32 and restart the installation

This makes no sense; the first sentence implies that the EFI System Partition (ESP) should be NTFS, but the second sentence explicitly says it should be FAT32. Your GParted output shows that the ESP (/dev/sda1 in your case) is FAT32, which is correct (the ESP must be FAT, and the last I checked, Windows expects FAT32 specifically).

There may be a translation issue here -- if the word "not" is removed from the first sentence, it is at least internally consistent and consistent with what EFI requires. That said, your ESP (/dev/sda1) is FAT32, not NTFS.

Looking more closely at your GParted display, though, you have two partitions that are marked as ESPs -- /dev/sda1 (which is your ESP) and /dev/sda2 (your Ubuntu root [/] partition). It's possible that /dev/sda2 having the "boot, esp" flag set is what's causing the problem. Thus, I recommend you remove that flag. (In this case, "boot" and "esp" are redundant flags. Both identify the ESP partition type code. You could do the same thing in gdisk by changing the type code from EF00 to 8300.) Be sure to change the type code of /dev/sda2 only -- do not change the type code of /dev/sda1. It might be worth deleting the partitions that the Windows installer created, too, and let it create them anew when you try again. Without seeing what it created, I can't know whether what it did was appropriate; it's conceivable that the Windows installer created something it shouldn't have because of its confusion over /dev/sda2 being marked as an ESP.

Note that Ubuntu doesn't care about partition type codes, so this error wouldn't have affected Ubuntu. Windows is more picky about such things.


Find and delete all files without extensions witin a folder and its subfolders

Try this:

find . -type f  ! -name "*.*"  -delete

However, note that the above will not delete files whose name ends in a ., for example foo.. To delete those as well, use this instead:

find . -type f  ! -name "*.?*" -delete


How to highlight second vowel from every word in a file?

Command substitution is not performed in single quotes, you'll have to use double quotes instead.
\e[1;30m is not a variable, so you cannot do ${\e[1;30m}.

Try:

sed 's:[AEIOU]:'"$(printf "\e[1;30m&\e[0m")"':i2' room.txt

Here, I close the single quote and then use double quotes, and then reopen the single quote.


Why does chmod 644 make directories inaccessible?

As noted in the manpage for chmod with relation to permissions:

  The  letters rwxXst select file mode bits for the affected users: read
         (r),  write  (w),  execute  (or  search  for  directories)  (x),  execute/search  only  if  the  file is a directory or already has execute
         permission for some user (X)

The executable bit on a folder is explained above as a 'search' permission; i.e. the execute bit merely allows you to access the folder in a file browser or to move to the folder from the terminal by running the cd command or running ls ~/folder to list the files in the folder.

The folder must be executable for the owner, although the superuser would still be able to access the folder as when using sudo any file or directory can be accessed or deleted. In addition, directory and file permissions are explained further in this useful article at Stackoverflow.

It is also important to note that 'executing' the folder doesn't mean you are actually running any code or commands like when a executable binary or script is run.

For a home Desktop user (though perhaps not for your server) most folders within $HOME have the execute permission set for user, group, and other if viewed with stat ~/myfolder (excerpt below):

Access: (0755/drwxr-xr-x)  Uid: ( 1000/    mike)   Gid: ( 1000/    mike)

The standard permissions for folders within $HOME are 755 or 775 and for files they are 644. However, the rest of the filesystem will differ.  Again, folders must have the execute bit for the owner or they will not be able to be opened by him. It is important to be careful with chmod when changing permissions and particularly when doing it recursively as the situation can quickly get messed up.

For more information, see man chmod or the Ubuntu manpages online, and this article at Superuser.


Postfix not receiving mail from email but does from sendmail?

Gah! Terribly sorry for wasting everyone's time. The problem was a very simple error I made because of my ignorance. From the same question on another Stack Exchange site:

  You've set your MX record to "mail.example.com". That means that when any mailserver tries to send mail to you, they will do a DNS lookup to find mail.example.com. Since that doesn't exist, the sending system doesn't know where to send the email.
  To fix this, do either of the following two things:

  Remove your MX record entirely. As long as you don't have an MX record, the sending system will instead do a DNS lookup for example.com, and since that does resolve to the server running your mailserver, that will work.
  In addition to the MX record, create an A or CNAME record for mail.example.com.

  It should look like his for an A record:

mail     A     127.0.0.1

  (except, of course, the IP address should be the actual IP of the server, not the loopback address)

  and like this for a CNAME:

mail     CNAME example.com.


How to create an encrypted archive in GNOME 3.22?

then how do you do it?

7z a file.7z ./ -p

It prompts you for the password.


Cannot run Ubuntu after installation. Black Screen

I had faced the same problem before. I reinstall ubuntu again. Before installation, you need to learn the installation process from the different tutorials.


GParted Closing When Applying Operations

If GParted closes when an operation is applied, then that is not normal and sounds like a bug.

Can you try performing one step at a time and applying?  That will help to isolate what step is failing - the fat32 resize, or the ext4 file system create.


The project and status can be found at ubuntu.com in the phone tab.

Right now the project is in early development and the currently supported handsets are the nexus devices.


Fan. Tastic.

For anyone else wondering, here is what worked:

sudo apt-get install gparted
sudo gparted
Ensure that you've selected the right drive in the upper right corner of gparted.
Device > Create Partition table.
Select gpt (msdos did not work as the link provided by Terrance suggests) and then click Apply.
Partition > New. Give it a name. Click Add.

That SHOULD work....it did for me.


How to diagnosis and fix fast battery drain on XPS 15 9560?

Dell XPS15 9550, ubuntu 17.4 + kernel 4.12 + native nvidia drivers -
 consumes around 10w-13w on 40% brightness settings.

/etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_sleep=nonvs"


Whats the best solution for mail, contact, calendar and task syncing?

I assume you want instructions for a server, but you don’t specify whether you just want instructions for setting up clients.

As you need to sync with Microsoft Outlook, you only have one option: the Exchange ActiveSync protocol. However, I’d recommend you also look into the open-source protocols CalDAV and CardDAV. They’re not supported in Outlook, but they’re supported by iOS, OS X, Android (requires free apps), GNOME, and KDE.

You can setup Horde groupware on your server. Horde can act as a calendar and contacts server and provides access to that data in a web interface, over the Exchange, CalDAV, and CardDAV protocols. Horde is mostly known for being a great webmail (IMAP front-end), but it also does a good job with contact and calendar management.

See the above link for complete instructions on setting up Horde for calendaring, contacts, and email for one–fifty users.


Can I restore a folder that suddenly disappeared?

Check out this link on how to restore files that where deleted by accident or crash:
https://www.howtoforge.com/data_recovery_from_accidently_deleted_files_or_crashed_drives_in_ubuntu

Another good option might be PhotoRec:
http://www.cgsecurity.org/wiki/PhotoRec

Yet another great source on data recovery:
https://help.ubuntu.com/community/DataRecovery

Good luck!


Running Ubuntu 14.04 lts only folders I can access is in the home folder and all others I am denied access. how can I fix this?

You need to take ownership of the directories you want to access.

Open terminal

sudo -s  hit enter and authenticate

chown -hR root /u

(change root to the username you want to take ownership) (u is the file path)

Here is an example:

chown -hR username /home/username/.config/ibus

The syntax -hR takes ownership of subfiles and folders too!

Remember command line in linux IS case sensitive.

Why did I lose 2 points for answering this question correctly? It is 100% correct on the money, you just need to take care with which directories you take ownership of as it can cause security issues!


Ubuntu boots up and becomes unresponsive as soon as I see the desktop

This happens when when your drivers are not compatible with your hardware.so u need to download the compatible ones.

first of all open the grub menu by clicking f6 or f7 when ur PC starts(depending on ur PC)and then open the OS in advanced-> recovery mode and then click on fail safe X mode and if it shows that you are low on graphics,cannot detect screen and devices then the problem will be mostly due to the driver.
Now depending on your hardware install the drivers from the internet whether its nvidia drivers or ATI etc.
Then go to the setting option->software and updates-> additional drivers->then selct anyone of the drivers and then click on apply changes and then restart your PC.

This will do your work if the problem is with the drivers.


You can investigate an issue by reading systemd-logs:

journalctl --since today

Please, find the shutdown logs and put here.


How to move my Trash into /tmp or automatically empty trash on reboot?

Why don't you use another approach:

Crontab combined with command line client for trash

Install trash-cli  / sudo apt-get install trash-cli, which will allow you to control your trash folder from shell.
Open your crontab with crontab -e in shell (will open your default shell editor chosen by select-editor)
Add an entry like

# In your crontab
@reboot    empty-trash > /dev/null

Now on every reboot your trash will be emptied. You can specify other times to empty trash. Just look at a crontab tutorial to learn how.

Of course you can use your link approach from above just as well. The problem with your approach was that you copied the link. Most likely that broke the link. Also your newly created folder /tmp/my-trash/ didn't have the proper directory structure of a trash folder specified by the free desktop standard. That can be remedied in the following way: (FIRST empty the trash manually)

mv -r ~/.local/share/Trash/ ~/.trashcopy
cp -r ~/.trashcopy /tmp/.trashcopy
ln -s /tmp/.trashcopy ~/.local/share/Trash

To make that change persistent, you have to include the following line in your user's crontab with crontab -e or just the part without @reboot in your ~/.bashrc.

@reboot  rm -r ~/,local/share/Trash; cp -r ~/.trashcopy /tmp/.trashcopy; ln -s /tmp/.trashcopy ~/.local/share/Trash


Every Screensaver in XScreensaver is showing in Show Applications

Follow these steps:

Copy the folder containing all the .desktop launchers associated to those screensavers from /usr/share/applications/ to ~/.local/share/applications/.
Open the copied .desktop files in the folder with a text editor.
Add the following NoDisplay line (or change if it already exists) to all the files

NoDisplay=true

Save the files.


Go to about:config in Firefox
Search for permissions.default.image
Change the value to 2 (default is 1)

An explanation can be found here: https://support.mozilla.org/en-US/questions/961547


Hidden Permissions - Zentyal Admins can't access User's Created Folders

I have only a little Ubuntu experience, and less Zentyal experience, but I had a similar issue today. I was restoring files from an old Ubuntu/Samba fileserver to a new Ubuntu/Zentyal fileserver. I set/updated ACLs, used my administrator:adm ownership, but could not browse on a windows client. I then did a chown shareuser:sharegroup (a user/group that actually needed the files) and it worked fine. Maybe that's obvious or redundant in your case, but on the outside chance it could help, I'm posting.


Ubuntu freezes when copying files to shared drive

This is very odd that you're seeing it with all of your attempted tools (Nautilus, cp etc.) and that you're seeing it on both USB and Samba shares. That's suggestive that something else is going on.  I would recommend installing iotop (must be run under sudo/root):

$ sudo apt-get install iotop
$ sudo iotop

This will help you get an idea for what's going. If things look like they're hanging you could throw in a 'sync' command to see if something is getting hosed up with the file getting stuck.

$ sync

Also using:

$ top

Can allow you to monitor the process to see if it's hanging.

Finally, I use rsync for my network transfers (for a variety of reasons like the ability to resume and to view progress) so you may want to explore using rsync.

$ rsync -v --progress /path/to/myfile /path/to/destination/

There are other reasons you could see this too that could be related to hardware or impending hardware failures.


Nothing will appear since there is no echo feedback when you type your password. When it asks for the password, just type it and press the enter key.


bind9-dyndb-ldap, BIND, named.conf: "cannot parse settings" during service start

UPDATE: SOLVED
I found this Bugzilla link at Red Hat: https://bugzilla.redhat.com/show_bug.cgi?id=1436268

If server_id is not defined, it crashes.

So, I just added

server_id "[hostname of the machine]"

to the dyndb section of my named.conf file, and it started right up.

Hope this helps.

Original Post

I'm upgrading from Xenial to Bionic and have the exact same problem, and an almost identical config as yours.  Best I can tell, I've rewritten my config file into the new dyndb format.  Had to change the option formats from:

arg "uri ldaps://example.com"

to

uri "ldaps://example.com"

The only difference is my password is unquoted as the directive is for an unquoted string (though it doesn't complain if quoted).

No matter what debug level I set, I don't seem to get any more details that it cannot parse something.  All of those are valid config directives, so I'm stumped!

Since this is all being built in docker, I can always use the Xenial image as my older DNS container images build and deploy fine with the older packages, but I'd like to figure out what part of the config this one doesn't like.

For what it's worth, I did get it to spit out the expected grammar for the dyndb LDAP module, though it was all what I expected.

22-Jan-2019 01:29:03.990 expected grammar:
auth_method <quoted_string>;
base <quoted_string>;
bind_dn <quoted_string>;
connections <integer>;
directory <quoted_string>;
dyn_update <boolean>;
fake_mname <quoted_string>;
krb5_keytab <quoted_string>;
krb5_principal <quoted_string>;
ldap_hostname <quoted_string>;
password <string>;
reconnect_interval <integer>;
sasl_auth_name <quoted_string>;
sasl_mech <quoted_string>;
sasl_password <quoted_string>;
sasl_realm <quoted_string>;
sasl_user <quoted_string>;
server_id <quoted_string>;
sync_ptr <boolean>;
timeout <integer>;
uri <quoted_string>;
verbose_checks <boolean>;


It goes to home directory after last pop because you were in your home directory when you pushed /tmp/dir1 onto this stack. ~ is your home directory. This part:

user@ubuntu:~$ pushd /tmp/dir1
/tmp/dir1 ~

Specifically, when the directory stack is empty, it adds current working directory to the bottom of the stack.

Here's an example from /etc:

bash-4.3$ cd /etc
bash-4.3$ pushd /usr
/usr /etc

The popd behavior is also proper, it did remove the oldest pushed directory, but you also missed the part that it goes to the new top directory after the old was removed. Read the manual again:

  popd [-n] [+n] [-n] Removes entries from the directory stack.
  With no arguments, removes the  top directory  from  the stack, and performs a cd to the new top directory.

So  in your case with stack /tmp/dir2 /tmp/dir1 ~ , first popd removed /tmp/dir2. So what's the new top of the stack ? /tmp/dir1, so it will also perform cd /tmp/dir1.

Observe:

bash-4.3$ pwd
/etc
bash-4.3$ pushd /bin
/bin /etc
bash-4.3$ pushd /usr
/usr /bin /etc
bash-4.3$ pushd /sys
/sys /usr /bin /etc
bash-4.3$ popd
/usr /bin /etc
bash-4.3$ pwd
/usr


"no such file or directory" when importing daloradius schema

It looks like daloradius-0.9-9/contrib/db/fr2-mysql-daloradius-and-freeradius.sql doesn't actually exist because the file was extracted elsewhere.

However, you don't need to download the entire repository tree if you just need that one file. This should be enough:

wget https://raw.githubusercontent.com/lirantal/daloradius/master/contrib/db/fr2-mysql-daloradius-and-freeradius.sql
mysql -u freeradius -p radius < fr2-mysql-daloradius-and-freeradius.sql


"Welcome to emergency mode!" Think it is a fsck problem

You could run fsck from Ubuntu Live.

Switch on your computer. Boot into a Ubuntu Live DVD/USB (try it without installing).
After it loads, open a terminal by pressing Ctrl+Alt+T
In the terminal, run:

sudo -i
fdisk -l

fdisk will inform you what your partition / (root) is called.  In this question it is /dev/sdb1.

Then you should continue by running:

umount /dev/sdb1
fsck -y /dev/sdb1
poweroff

If the umount command complains that sdb1 is "not mounted", that is not a problem.  We wanted it to be "not mounted" :).
Remove the DVD/USB.  Switch your computer on again, to boot from the SSD.


How to reinstall MBR and UEFI Grub in Ubiquity installation?

( you should place a /boot partition at the beginning of your disk , also EFI boot needs a fat32-EFI ESP partition )
The good:
as long as you find the inital ram disk initrd , the kernel file vmlinuz and the command line ( either from grub config or manually fiddling → e.g. find the root from /etc/fstab  ) , YOU WILL BE ABLE TO BOOT from another medium (CD/USB) that has a grub/lilo/syslinux ..

see here for manual booting

The Bad:
the operation might be tiddly ( see below )
The ugly:
Recommendation would be : chroot from another (live or not ) linux-system after bind mounting /proc /dev/  /dev/pts and /sys, decide for whatever GRUB fits your partition layout ( either MBR if you have MBR  OR UEFI if you have GPT Layout ) , and let install-grub do it's magic after you reconfigured your packages with  dpkg-reconfigure -plow grub-whatever

to see if you have UEFI deployed: search for the EFI partition or a respecting folder in a FAT Partition

manually switching to EFI mostly requires changing from MBR to GPT ( so you need to backup/transfer the partition since you format the whole drive

also there are by default 2 ways to install grub one does UEFI one MBR , you might also deploy both , since both ways just access the /boot ot / partition , but ubuntu scripts ( and packages ) are different ones

in trouble you can also PXE-boot(Network)/CD-boot with GRUB

Remember that UEFI mostly NEEDS a GPT partition table which you might not have

for MBR the boot flag needs to necessarily be set in most situations , but for GRUB in  a partition


The question "What is the difference between apt and dpkg?" is a duplicate of https://unix.stackexchange.com/questions/104592/what-is-the-difference-between-apt-get-and-dpkg.
Short answer: They do different jobs, and work together. Most of your interaction will be with apt.

Your REAL question seems to be "How do I install libinput-gestures?"
Answer: You follow the install instructions at https://github.com/bulletmark/libinput-gestures
Nobody has packaged libinput-gestures for Debian/Ubuntu, so you will find the dependencies in the Ubuntu repositories and installable by apt, but you WON'T find a package by that name.
Neither apt nor dpkg install random github files.


How to limit resource usage for a given process?

You should use a combination of all cgexec, cpulimit and ionice:

Limit RAM and SWAP:

sudo cgcreate -g memory:/szMyGroup
echo $(( 512 * 1024 * 1024 )) | sudo tee /sys/fs/cgroup/memory/szMyGroup/memory.limit_in_bytes
echo $(( 1024 * 1024 * 1024 ))  | sudo tee /sys/fs/cgroup/memory/szMyGroup/memory.memsw.limit_in_bytes

The above commands create a control group named szMyGroup (E.g. in your case group-great-uncle), set a cap to the processes run under szMyGroup up to 512 MB of physical memory and up to 1024 MB of swap and then:

sudo cgexec -g memory:szMyGroup szMyProgram

which will run your program under the szMyGroup control group, thus ensuring they adhere to the limits
limit the disk IO:

sudo ionice --class 3 --pid $(pgrep -f szMyProgram)

The above command uses pgrep with reusing parts of the current command-line to limit its disk access to only use the disk when no other program is using it
Limit the CPU:

sudo cpulimit --limit=25 --pid=!#:4

The program's CPU is now limited to 25% of maximum

If the program does not use a lot of CPU to begin with, lower the value of cpulimit to half or less of what it currently uses.


Boot from the Ubuntu installation media you have created.
Highlight Try Ubuntu without installing and press the E key.
Add the parameter nouveau.modeset=0 to the end of the linux line.
Press the F10 key to boot into the Ubuntu Live desktop environment.


Ubuntu hides the menu bar behind the title in the panel at the very top of the screen.  When you mouse over that area, menu items such as "Media" and "Edit" should become available.

From there, you'll be able to import your music via Media > Import.


To renew your dhcp lease at the terminal:

sudo dhclient -r; sudo dhclient


Looks like the backup file was not saved correctly on the USB pen.

Try to make a new one and check the size of it or if possible use another USB pen, when broken they have a tendency to corrupt files. Make sure to eject the drive before removing it from the computer.


ImageMagick Crop image keeping original position

Solved by snibgo in ImageMagick official forums:

convert 1200px-Stratton_Oakmont_logo_svg.png -crop 550x800+320+30 -background Blue -layers Flatten x.png


Only allow one user on system to be SSH'd into

Edit your config file sudo nano /etc/ssh/sshd_config (or use vim, kwrite, whatever editor instead of nano)
Add this line AllowUsers otheruser and possibly DenyUsers myuser
Save and close sshd_config file
Reboot your machine or restart SSH service sudo systemctl restart sshd
AllowUsers

This keyword can be followed by a list of user name patterns, separated by spaces.If specified, login is allowed only for user names that match one of the patterns.*' and?' can be used as wildcards in the patterns.Only user names are valid; a numerical user ID is not recognized.By default, login is allowed for all users.If the pattern takes the form USER@HOST then USER and HOST are separately checked, restricting logins to particular users from particular hosts.

DenyUsers

This keyword can be followed by a list of user name patterns, separated by spaces.Login is disallowed for user names that match one of the patterns.*' and?' can be used as wildcards in the patterns.Only user names are valid; a numerical user ID is not recognized.By default, login is allowed for all users.  If the pattern takes the form USER@HOST then USER and HOST are separately checked, restricting logins to particular users from particular hosts.


Installing Ethernet Card driver while inside Live CD

(rtl8723au is not an Ethernet driver, but a wireless network adapter driver.)

While you could do complicated things just to get a network connection during the installation process, I suggest to drop that idea and just proceed without network connection. Then, after the installation has finished, boot your fresh installation, install the driver and update packages. This has the same result.

If you would like to have a network connectiong during the installation that requires that driver, you could open a terminal and invoke the commands. Note that a kernel module requires more than just make, you will also need kernel headers matching the target kernel (linux-headers-3....-generic) and a compiler (gcc). The compiler and make are installed with the build-essential package. For offline package installation, see How can I install software or packages without Internet (offline)?

When booting the Live CD, chose for Try instead of Install. You will then start a graphical desktop where you can look for the Terminal application to invoke the commands. If you have a USB, you could then also use the graphical file browser to find out.

Be also aware that manually installing a driver module like that will break every time you update your kernel. To avoid that trouble, you could DKMS to rebuild your module at every update, and/ or file a feature request at the Ubuntu Bugtracker (Launchpad) for driver inclusion (if it was not already available).

The linux-image-extra-3.13.0-30-generic package ships with the rtl8723ae module which should support built-in PCIe cards, so maybe you do not have to go through that trouble of manually installing a driver. Note the e suffix for PCIe, you mentioned the rtl8723au module which exists for USB devices, but maybe that was a typo?


How can I set the 'Path' variable in a .desktop file to be relative to the location where the desktop file is located?

You can kludge around this by using an in-line bash mini-script on your Exec. This will add the .desktop file's path to PATH prior to running your command.

Exec=bash -c "export PATH=$PATH:`dirname %k`; your_command"

%k will be substituted by the path of the desktop file itself. The dirname command chops off the filename part, leaving only the directory. Once PATH is set like this, your_command can be invoked without a full path.


I just tested your php file in my server and it works just fine.

You problem must be that the user www-data doesn't have write permissions to that folder.

If indeed that user doesn't have write permissions to that folder, then you will see error messages at the file /var/log/apache2/error.log

In order to look at the last errors, do

tail -n 15 /var/log/apache2/error.log

For example, if I, instead of "test.txt", put "/test.txt" (write to /, were only root can) I get this error inside the log file:

[:error] [pid 7505] [client 127.0.0.1:47066] PHP Warning:  fopen(/test.txt): failed to open stream: Permission denied in /var/www/html/a.php on line 2

The above clearly states that permission is denied.

You can fix this problem by giving write permission to that folder for user www-data.

give specific user permission to write to a folder using +w notation


Ubuntu 13.04 causes other pcs internet to be slow?

I was having the same problem and it was driving me nuts, so I installed a fresh copy of 12.04LTS and the same thing was happening. which was weird 'cause that's never happened to me before. I then disabled the proprietary driver for the wireless card, rebooted and no more slowing down my network.  Try that, hopefully it will be your solution as well.


Does every i5 i7 intel processor have intel graphics on board?

As far as I'm aware all core i3/i5/i7 processors come with the Intel GPU built into the processor and are sometimes used for dual graphics laptops with nvidia or ati...  Their IS a way to disable ATI graphics though and just use Intel's own...

How to completely shutdown Ati card


How to Install Completly amdgpu-pro on Ubuntu 18.10?

AMD hasn't released a driver for 18.10 yet. You've probably installed the driver for 18.04 (which is the latest), and that fails miserably (don't ask me how I know). To fix this, try switching to another virtual console (e.g. CTRL+ALT+F2) or boot in safe mode.

After that you have to manually remove all driver packages. You can search for them using: dpkg -l | grep amdgpu.

Then to remove them use apt remove --purge .... For some packages that doesn't work and you have to remove them manually:
dpkg -r -P ...

Finally I had to reinstall gdm3 (or lightdm if you use that) to get it going:
apt-get install --reinstall gdm3.

Then reboot and it should work.


I found one bug in in the mongodb charm's hooks.py script. On line 1053, we see a call to enable_configuresvr function:

enable_configsvr(config_data['config_server_port'])

However, enable_configuresvr's function parameter list does not match:

def enable_configsvr(config_data, wait_for=default_wait_for,
                 max_tries=default_max_tries):

The config_data['config_server_port'] shouldn't be the parameter passed; config_data should be.

The same problem is on line 1069 with enable_mongos passing config_data['mongos_port'] instead of config_data.

I'll try to run some tests to confirm these are the only bugs.

Outside of filling a bug report, has anyone else experienced this problem? It seems like it should be more wide-spread that just Conrad and me :P


I am using 16.04 and I have very few problems. On some wi-fi networks when I mount my windows partitions gvfs goes at 100%. Killing the process fixes it with no problems. There are reports of a lot of people having problems with the network manager and wi-fi networks but I haven't seen that. Overall I 'd say 16.04.1 is quite stable.

If I were you before downgrading I would install all the software I need for the course and test them to see they are working fine. If they do then I 'd suggest you stay at 16.04 because of the newer features it has, notable among them better secure boot support.

If you run into any problems and decide to install 14.04 you can get it from here.


Add calling and sms to Vodafone Dongle K3772

You can SMS through vodafone-mobile-broadband package:

sudo add-apt-repository ppa:crass/v-mobile-broadband
sudo apt-get update
sudo apt-get install v-mobile-broadband


I've started using my new Series 9 laptop by immediately installing Ubuntu/Kubuntu on it.

My experience so far (other than having a fancy machine) is mixed.

Pros:
 - almost everything worked out of the box
 - amazing speeds
 - best quality laptop display I have ever encountered

Cons:
 - had to make a research on how to make the wireless driver work
 - had to make a research on how to get the right click functionality
 - had unidentifiable crashes almost every day, usually couple of times a day (8-10 hrs of usage daily).
 - had a lock up once that even made it impossible to do a hard reset holding down the power button. Given that it has built in battery and 6..7hrs of battery life, it was a huge annoyance.

I am unsure if the crashes are somewhat Linux-specific, did not use Windows. Because of them I am thinking of returning the laptop.

You may find some other guy's similar crash experience here.
Other issues are covered here.


When installing things on Ubuntu, you're much better off using packages provided for your version of Ubuntu, rather than from other sources.

To install a package offline, you can do something like this:

apt-get install --print-uris mysql-server

This will print out a bunch of URLs. You can download these from another computer, and transfer them to your Ubuntu machine, putting the .deb files into /var/cache/apt/archives.

Once you've done that, do:

sudo apt-get install mysql-server

And apt will find the package files you've downloaded, and install mysql.


Solved by fresh install. Couldn't find any reason, therefore any solution.


Apache reverts PHP version after inactivity

I had puppit installed, and it was changing the version back every 30 minutes.
Looked like inactivity but wasn't. Oops!


Windows 7 not showing in OS selection menu at start up

As GRUB can't detect your Windows system, the best way to solve this is to create a manual entry to Windows.

Edit /etc/grub.d/40_custom (you will need root permission) and add the following at the end:

menuentry "Windows 7" {
    insmod part_msdos
    set root="(hd0,msdosN)"
    chainloader +1
}

you will have to replace "N" with the correct windows partition where you have Windows 7 (if you don't know which one it is you can use gparted or if it is available, "Disc Utility"). So if your Windows partition is /dev/sda3 the correct text would be

set root="(hd0,msdos3)"

After that just run sudo update-grub2 and you should have a new entry once you reboot.


How can I change the keyboard shortcut for Emoji picker?

On needs to run ibus-setup and in the "Emoji" tab

....change the shortcut (click on the three dots that are focused in the screenshot). I had to restart my computer after that so that the change would take effect (not sure how to restart IBUS).


Mouse cursor disappears in Ubuntu 13.04 under VMware

Solution written by OP inside the question:

  Finally I used "Gnome Fallback" as my desktop manager and all of a
  sudden I got a cursor.

  This works for me now, although I would really like to try using the
  new KDE desktop as well as Unity.

  It appears to me to be a problem with compiz (perhaps) or at least has
  something to do with the VMWARE XORG drivers as they interact with
  13.04 (my guess).

  Hope this helps someone else out .. maybe someone can figure it out
  from here.


How to keep version number in a single place in a python project with setup.py and debian/control

A tool/command is used to generate a version.py module with the version number. However, this doesn't work well with launchpad recipes because the ability to run arbitrary commands in a recipe is disabled in launchpad.

You can, of course, do that at build time, rather that at source-package-creation time.

version.py:

# Overwritten during Debian packaging build
package_version="unknown"

debian/rules:

override_dh_auto_build:
        dpkg-parsechangelog | sed -rne 's,^Version: (.*),package_version="\1", p' > version.py
        dh_auto_build

debian/clean:

version.py


unable to browse the server throught apache

From the ll command you posted, it seems that home3.com is a file, and not a directory.

While the DocumentRoot directive is /var/www/html/home3.com.

So when accessing that IP, Apache is trying to load /var/www/html/home3.com/index.html which does not exist, hence the 404 error.

You need to change the DocumentRoot directive to /var/www/html, and access the page with http://192.168.37.132/home3.com instead. Or make home3.com a directory, and create an index file inside that directory.


(Fresh-)Installed Windows 10 and Ubuntu 17.04, can't dual boot and GRUB is gone

I just encountered the similar scenarios as you. The following script in terminal works for me:
My systems: windows10 and ubuntu 17.04

Please try:
sudo update-grub
sudo grub-install /dev/sda
sudo update-grub

also, please be noted that "boot-repair" didn't work and caused grub loss and unable to boot up for my computer.

Hope this works for you.

HW


It could be you need to switch servers because the one your are downloading from is down

It could be some PPAs were not found. If so try this

Please note the entire error messages aren't visible on your screen snapshot.


Skylake integrated graphics on Ubuntu - Help!

For Ubuntu 15.04 you will need to add these kernel commands to your grub configuration. i915.preliminary_hw_support=1 and also nouveau.modeset=0

I am unable to get Nvidia drivers working on 15.04.

On 15.10 I have yet to see Intel or Nvidia working for myself.

EDIT: On Ubuntu 15.04 I was able to get Nvidia graphics working. Leaving those kernel commands in place i installed via CLI nivida-346 nvidia-prime nvidia-settings, rebooted and everything worked.


How to disable ctrl-shift-e keybinding from showing eEEEE and loading Emoji options

In terminal type ibus-setup, go to the emoji tab, and delete the keybindings.


You seem to be a little confused as to what "listening" on a port means. In order to listen for incoming connections on a port, an application must explicitly tell the operating system that it is willing to accept connections on that port. As Bert mentioned in his answer, listening on port 77 will (with the default configuration) require root privileges.

If you want to create a simple "test" server that can be set listen on a specified port and that you can interact with, take a look at the  netcat command . Basically you want to do this:

sudo nc -l 77

Now try to run your Qt application. You should see "Hello Server" displayed in the terminal that is running netcat. If you change the timeout in QTcpSocket::waitForReadyRead() to something large (like 30000, equal to 30 seconds), you can experiment with sending replies back to your application.

For example, launch the netcat command again and run your Qt app. After the terminal displays "Hello Server", type something into the terminal and press the Return key. Your Qt app should print whatever you typed to the console.


How to change working directory when open a file with double clicking on ubuntu desktop?

Although this is years later, here's what worked for me:

Exec=bash -c 'cd "%k" && ~/path/to/your/file'

%k gives you the path of the directory of the launcher you just launched.


I am answering my own question. Thanks to Eliah Kagan and Anwar Shah for suggesting it.

From the comments i was inclined to post it as  Feature request , and posted it at Ubuntu Brainstorm under the heading

  Smarter way of navigating the Active application Windows in
  UNITY

They further suggested to post it as Unity design improvement through

  The Unity design process (and how you can play a part in it)

I did and asked in launchpad here under the same title

  Is it possible to auto-arrange the active Unity launcher
  icons?

Where i was led to subscribe Unity design mailing list also known as  the “Ayatana Discussion” team .

Well the answer here now stands as Requested Feature , which means it is no longer helpful here . So i am closing it . If in future releases this gets addressed , i may vote to Reopen it.

  Thank you, for All the Help :)


Can I install LAMP server on Ubuntu One private cloud?

No. UbuntuOne is a could personal files storage system, it will not run the services for you.

Having said that you can have a service running in your computer and have those files be stored in the cloud, that would mean that your computer is responsible for the reply to any request done in a running server (HTTP server, SQL server or anything else) and would use your stored files in the UbuntuOne.

That would have serious degradation in the performance making it hard to justify since any change done in your local files would be then synchronized to the UbuntuOne servers, 1 request once in a while is fine, turn that to a few dozen and it would just burst.

A better option for that type of features is really use something like Amazon EC2 instance and have your services running there. Ubuntu can deploy and configure that on the fly using Juju Charms.

Form more information on cloud services using Ubuntu please have a look at http://cloud.ubuntu.com/ and https://jujucharms.com/ for the charms deploy process.


Do not download the tar file (link downloads v2.3.0) (other releases) because there are some important pointers AND at the end of writing this (made it on the fly) I found out it was easier than you would think (though the installation is so obvious I wasted time making this ;) ). Skip to below the image if you do not want to install the source version (ie. the download on their website).

openvSwitch has a release for specific kernels.

Version Linux kernel
1.4.x   2.6.18 to 3.2
1.5.x   2.6.18 to 3.2
1.6.x   2.6.18 to 3.2
1.7.x   2.6.18 to 3.3
1.8.x   2.6.18 to 3.4
1.9.x   2.6.18 to 3.8
1.10.x  2.6.18 to 3.8
1.11.x  2.6.18 to 3.8
2.0.x   2.6.32 to 3.10
2.1.x   2.6.32 to 3.11
2.3.x   2.6.32 to 3.14

Ubuntu 14.10 has 3.16 ...

$uname -a
Linux schijfwereld 3.16.0-24-generic #32-Ubuntu SMP
Tue Oct 28 13:07:32 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

Here is a list of Ubuntu versions with their kernel versions:

List of Ubuntu Versions with Corresponding Linux Kernel Version

Current supported Ubuntu releases:

12.04   Precise Pangolin 3.2+
14.04   Trusty Tahr      3.13

If you want to be sure to get a working installation from the tar.gz (at the moment) 14.04 is adviced. In general I would not make a remark about this but this software clearly has a direct relation to the kernel version. So installing it on not supported kernel releases is not advised.

After downloading you will have a tar.gz file in your ~/Downloads. Open the file with fileroler and check the installation file. "INSTALL: is a generic Linux installation guide but there are PLATFORM specific installation files in it (wow, that's a first!). You need "INSTALL.Debian" for Ubuntu.

The installation starts with a comment:

  Before You Begin

  Before you begin, consider whether you really need to build packages
  yourself.  Debian "wheezy" and "sid", as well as recent versions of
  Ubuntu, contain pre-built Debian packages for Open vSwitch.  It is
  easier to install these than to build your own.  To use packages from
  your distribution, skip ahead to "Installing .deb Packages", below.

  Installing .deb Packages

  These instructions apply to installing from Debian packages that you
  built yourself, as described in the previous section, or from packages
  provided by Debian or a Debian derivative distribution such as Ubuntu.
  In the former case, use a command such as "dpkg -i" to install the
  .deb files that you build, and in the latter case use a program such
  as "apt-get" or "aptitude" to download and install the provided
  packages.

  You must be superuser to install Debian packages.

  Start by installing an Open vSwitch kernel module. See debian/openvswitch-switch.README.Debian for the available options.
  Install the "openvswitch-switch" and "openvswitch-common" packages. These packages include the core userspace components of the switch.

  Open vSwitch .deb packages not mentioned above are rarely useful. Please refer to their individual package descriptions to find out whether any of them are useful to you.

So the manual suggests that there are debian packages (of course... I should have started checking Ubuntu Software Center). So let's open up Ubuntu Softeware Center and search for it.

So to answer your question:

  Can any one introduce me to a good and simple tutorial about installing Open Virtual Switch directly via the Linux kernel?

It seems the answer would be yes (it consists on 2 packages available in your software center) so you can do it from our software center or from command line:

  Installation made easy

Depending on your needs you may need more components but the base installation will be:

sudo apt-get install openvswitch-switch openvswitch-common

Refer to the install guidelines in the tar.gz or the descriptions in our software center or the website your linked for more information about packages related to this installation.


How to use bleachbit to clean other mounted drives and specific folders?

As of BleachBit 2.0, deep scan defaults to the home user directory. There is not a way in the GUI to change it, but I think this will work

Copy the deepscan.xml that came with BleachBit to ~/.config/bleachbit/cleaners
Change id="deepscan" to id="mydeepscan"
Add the attribute path="/media/device1" to each <action> element

Then a new DeepScan option will show up, and you can select it.

You may also want to change the <label> elements too.

Update, here is a working, tested example of an option that cleans logs in /var/log instead of in the user home directory. Notice there is an attribute path=

 <option id="log">
    <label>Log</label>
    <description>Delete the logs</description>
    <action command="delete" search="deep" cache="false" path="/var/log" regex="\.log$"/>
  </option>

Please note that this XML goes into a CleanerML .xml file. In my case, I added it to the existing deepscan.xml, but it could go into a new .xml file that is in the right folder.


In Ubuntu Server 16.04, what partition type should I use for system space?

For your system partition chose Ext4 journaling file system

For your swap partition of course the swap area file system


Unfortunately xclip silently ignores invalid command line options:

There is no -s option as both -selection and -silent start with -s. You have to use at least -se.

As xclip just ignores your -s option the commands

xclip -s primary -o
xclip -s secondary -o
xclip -s clipboard -o
xclip -s asdfghj -o

all just use the default selection (primary).

For the selection name only the first character is actually used, and if it is anything but s or c the default is used.

date | xclip -selection XA_PRIMARY
date | xclip -selection XA_SECONDARY
date | xclip -selection XA_CLIPBOARD

all use the primary selection.

Use something like

date | xclip -se p    # write to primary selection
xclip -se c -o        # read from clipboard


If your aim is to resize your disk partition all you have to do is follow the instructions given on the page https://help.ubuntu.com/community/ResizeandDuplicateWubiDisk. That's if you installed Ubuntu by running wubi.exe. If this isn't the case I'll let someone else answer your question.


In my experience, if you had one giant L3 network managed by a single admin team, with no firewalls segmenting the network, you could deploy a super-simple layout.  Depending on the number of endpoints you want to commission/deploy with MAAS, you might be able to handle it all with a single virtual MAAS server.   But nobody has that network design (and if you do you should change it...).

There's not enough information in your question to give you specific answers.  In general terms, MAAS doesn't require any special considerations.  You should put rack controllers in places where your end points can reach them for DHCP, PCE, TFTP, etc.  Region controllers need to chat with Rack controllers using a couple TCP ports.  So you will need to open firewall ports if you have firewalls between the region and rack controllers.

In our initial MAAS deployment tests, we made things very complicated -- rack controllers were physical servers with multiple nics.  We tried the "one nic per VLAN" model...then the "trunked vlan port with a BMC nic" model...  We had one design that had a management port, a vlan trunk (for DHCP), and a BMC/ipmi port.  All of that was waaaay overly complex.  In the end, we have a single rack controller with a single nic.  We use "ip helpers" to handle DHCP requests, and MAAS is virtualized to deal with basic HA.  Works like a champ.

So, in summary, don't over-engineer your MAAS deployment.  Try to deploy with the absolute least number of servers (and nics) possible.  Add more MAAS when you are blocked by external factors (e.g. firewalls, admin teams/roles, etc.)


Installation stops about 3/4 of the way through, nothing happens after I click "Skip"

The time that "skip" option occurs is usually when  the following happens:

Downloading updates
Downloading language packages
Downloading third-party plugins

The time to complete this tasks depends on your network speed. Usually the packages may be a total of several MB (>=100) so you have to be patient.

If you want a straight foreword simple installation Do Not enable "*install updates while installatio*n" and  "install third party plugin". You can install them after you have finished the installation


2 ip addresses for 2 Server on 1 computer?

I've made it work with giving the virtual host (etc/apache2/sites-enabled) an specific IP like so:

<VirtualHost 192.168.1.41:*>
..
(sitea)
..
<VirtualHost/>

<VirtualHost 192.168.1.46:*>
..
(siteb)
..
<VirtualHost/>


All of my USB flash drives are read only

I opened up the disks program and clicked on the USB stick icon and choose create a new partition table: msdos/MBR style. After that, I created a new FAT partition on the usb stick. I safely ejected the USB stick and then reconnect it. It didn't work initially but I restarted my computer and everything is working perfectly. I am now able to add items to my usb stick.


Trouble shooting internet connection problems?

WLAN access points being listed but a connection cannot be established may have many different reasons starting from incomlete installation of wpasupplicant (try latest version) to missing to incompatible network settings.

Check if the encryption setting (wireless security tab) for your neighbourhood are correct. If on a public AP you may not need any encryption.

I have a wired connection so unfortunately cannot give you a screenshot for wireless settings. I include a shot for wired LAN where at least some points are similar:

Access to network settings is right click on the network manager icon. Choose your connection then "Edit..". Note your setting in case you need to restore them. The tab IPv4 settings gives you access to DHCP settings where it should say "Automatic (DHCP)". From the tab IPv6 setting you can set "Method" to "Ignore" as you most likely don't use IPv6. In the unliely event that your AP does not provide DNS services you can add your own by choosing "Automatic(DHCP) adresses only" from IPv4 settings.

This may not solve your specific problem but gives you ideas where to start from. You may also find solutions here.


Try to find latest driver.
and go to interface -> property -> Advanced -> Wifi config -> Do not use "performance", choose "Wifi", and it may be better.


Fs is read only, "mount -n -o remount /" not working since the fs is not writeable

Try using the following command :

mount -o rw,remount /


Forget the command sudo dpkg --configure -a, you don't have mathlab installed.

Use only the command

sudo apt-get purge matlab-support

to remove the package.


openscad failes to install : broken dependcy libqt5scintilla2-12v5

I found an answer on https://github.com/openscad/openscad/issues/1792. You need to install several dependencies manually:

Download two DEB packages from https://www.ubuntuupdates.org/package/core/yakkety/universe/base/libqt5scintilla2-l10n and https://www.ubuntuupdates.org/package/core/yakkety/universe/base/libqt5scintilla2-12v5
Install them using sudo dpkg -i <package>. First libqtscintilla2-l10n, then 12v5.
Now you can install openscad using sudo apt install openscad.

Happy Hacking!


How can I make the scanner of a Canon E500 work?

I have the same problem.

You should try this : http://support-my.canon-asia.com/contents/MY/EN/0100397001.html


Ubuntu 16.04 USB or external authentication

Best approach

Look for a PAM module that will suite your needs. That's the best way to go about what you're trying to do!

If you can't find something in the repos, you could try scripting it. By combining udev, encryption, xdotool, unused space at the beginning of a USB drive, and tests to see if you're on the lockscreen, you can make it happen.

General How-To:

Create a secure password for your account
Encrypt (I use gpg and symmetric encyption) this password with a keyfile that you'll store some place safe on your computer
Use a hex editor to find unused space on your USB stick before the first partition that is at least as large as your encrypted password.
Write the encrypted password to space not utilized on your USB stick before the first partition (dd comes in handy here). Be really careful if you write to space that is used for filesystem management, you could "trash" your data!
If you're not confident in your ability to perform the last two steps without data loss, you could just save the encrypted file to your USB like any other file
Install the commandline program, xdotool
Write a udev rule to call a script on the insertion of a specific device
Write a script (that will be called by udev in the rule you just wrote)

checks the lock screen state
if locked, pulls the encrypted password off the USB (use dd for this)
decrypt the password with the key on the computer
use xdotool to send the password to the password input field followed by a return key stroke to login/unlock the system.

Write a udev rule to watch for removal of your USB stick. When it's removed, send command to lock the screen

By encrypting the password before copying it to the USB stick, you ensure that if you lose your USB stick, your password is not in plain text. If someone were to get the decryption key for you password off of your system, it's useless without the encrypted password which is stored on your USB.

Check out an answer I wrote to a different question where I provide more detailed instructions. That post could probably benefit from some updating, and if I have time to do that in the near future, I will.

This could easily be tweaked to check inserted USBs against a centrally managed master list on a server. Of course password storage might have to be managed a bit differently.


Virtualbox xp guest can't modify or delete files on shared folders

Maybe something silly, but when I connected a hard drive I needed to set write permissions in the Virtual Machine settings.


How to remove terminal's delay when working remotely

I believe the delay needs to be there. The terminal cannot guess if you are typing or there's some other event to be run on particular keypress. So after each key (or key combination) pressed your terminal needs to wait for the effect from the server. Which usually is adding a letter/character to the prompt.

You can press multiple keys in sequence without waiting for the answer, but you have to wait for the answer before the effect of typing would be visible.


Home folder in `root` and not in `home`... I'm confused!

The first screenshot ("as sudo") is shown in icon view, and the second screenshot ("as regular user") is in detailed list view, but they are actually showing the same folder structure. There is no discrepancy. (tachyons's answer explains why different folders have the house icon on them.) The detailed list view is giving you a bit more information; in particular, the folder called /home is expanded to reveal its contents, including the p_sardinha subfolder.
Since the two views are equivalent, there's doesn't appear to be problem relating to how you are viewing your folder structure. Therefore we can break your question down into two parts:

Where is my home folder?
How can I solve a problem where an application tries to access my desktop folder, but fails because it names that folder in the wrong language?

Where is my home folder?
Every human user of an Ubuntu system has a home folder (which is also called a home directory, since folder and directory mean the same thing). If you had user accounts set up on your Ubuntu system for more than one person, each one of them would have a separate home folder.
There is a folder called /home. That is not your home folder. In fact, that is never anyone's home folder. Rather, /home is the folder that contains human users' home folders.
Your home folder is /home/p_sardinha, because your username is p_sardinha.
More generally, for a human user username, the user's home folder is /home/username.

On some systems, including yours, the folder called /home contains a subfolder lost+found. This is not anyone's home folder. Instead, this exists by default in the root folder of ext2/ext3/ext4 filesystems; it is used to keep files that are recovered while repairing the filesystem, and it is not necessary for you to know anything about it, in order to use your home folder.

Some user accounts exist that do not correspond to actual human users of your computer. They exist so that certain programs can run with special identities, abilities, and restrictions appropriate for the tasks they are designed to perform. Non-human users generally do not have their home directories in /home. For example, as tachyons mentioned, the root user, which is the user actually running commands you run with sudo and gksu/gksudo (unless you use the -u flag) has /root as its home directory.

One of the reasons the distinction between the folder called /home and your actual home folder (which is a subfolder of that) is sometimes confusing, is that Nautilus (Ubuntu's file browser) calls your actual home folder "Home." For example, this is the contents of my home folder, shown in Nautilus:

The actual name of that folder (whose contents are shown), however, is /home/ek (since my username is ek). My desktop folder is called Desktop and located within my home folder, so its fully qualified path is /home/ek/Desktop.
How can I solve a problem where an application tries to access my desktop folder, but fails because it names that folder in the wrong language?
There might be an application-specific solution, but you haven't provided details about the circumstances under which the error occurs or what application it's happening in, so I cannot provide such a solution. Fortunately, I can provide a general solution.
Since folders are sometimes called something besides their real name (for example, your home folder is sometimes called Home even though its name is p_sardinha), first make sure that your desktop folder's name really is Área de Trabalho. It's easy to check this--just view the contents of your home folder (as I did, in the screenshot above), and make sure it's called that there. I believe you have already done this.
So the real full name of your desktop folder is /home/p_sardinha/Área de Trabalho. But at least one of your applications wants to access it at /home/p_sardinha/Desktop. Assuming there is not also a folder called /home/p_sardinha/Desktop (you should check to be sure), you should be able to solve the problem by creating a symbolic link called Desktop in your home folder, that points to Área de Trabalho (your actual desktop folder).
To create this symbolic link, open a Terminal window (Ctrl+Alt+T) and run these commands:
cd
ln -s 'Área de Trabalho' Desktop

The first command (cd, with nothing after it) makes sure the command-line you're using is "in" your home folder (that is, that it is using your home folder as its present working directory).
The second command (that starts with ln) actually creates the symbolic link.

That should solve the problem. However, your applications really should be internationalized sufficiently as not to assume your desktop folder is always called Desktop. Therefore, I recommend reporting a bug in the application in which the problem occurred, so the developers can make the application work as well for Portugese-speaking users as it does for English-speaking users.


Developing Unity compliant apps in Python - where to start?

Good question.

First of all, the appindicators are not Unity specific in any way. Actually, they run just as well on Xfce or KDE. It's very, very, simple to use. You'll create an indicator object, set the name of icons to use when it needs attention, etc, and simply attach menus to it. The indicators are then sent over dbus and properly displayed in a manner suitable for the current desktop environment. In Unity, Gnome Shell, Xfce and LXDE, it'll be displayed as GTK menus, and in KDE it'll be displayed as Qt menus, etc. Very neat. You can find more information about it here: http://unity.ubuntu.com/projects/appindicators/

In the right pane of Glade, you have a Signals page under Properties. Here you can simply type the name of the method to use as handler for that signal. In your code, you'll just create a gtk.Builder object, load the XML that Glade produces and use the gtk.Builder.connect_signals method to connect all your signals to their methods. This means you can use Glade interfaces in almost any programming language. Since that is so easy, and since languages are different by nature, it makes little sense to add coding to Glade itself. For coding Python (and other languages), I will recommend having a look at Geany ( http://apt.ubuntu.com/p/geany). It is a very good editor/IDE.

Other things in Unity are so new, there is little documentation, except as code examples. Some of the APIs are just now becoming stable, such as for Scopes and Lenses, which weren't even called that a little while ago. As a beginner, I'd wait a little bit before looking into those things.

The entries on the launcher, are actually just referred to as LauncherEntry in code, and it can use a progress bar, a counter and QuickLists. I haven't actually coded that myself, but this page has an example and it seems very easy, like the rest of the Unity APIs: http://bazaar.launchpad.net/~unity-team/libunity/trunk/view/head:/examples/launcher.py


Remotely access and use Windows machines

This depends on how you want to connect to the machines...

1 you can connect using software like teamviewer or vnc

this way doesn't enable you to login to the windows machine, but you can control the windows pc from your ubuntu desktop. this means someone will have to login there for you.
this doesn't really have to be a bad thing, as you can connect to e.g. a machine of your friend and help him out solving his problems - he sees the same things on screen as you do and you both can control keyboard and mouse.

teamviewer setup (www.teamviewer.com) is simplest and shouldn't need any explaination - vnc is a bit more difficult to install and (normally) doesn't work over network boundaries ("outside" of your current network)

2 you can connect to your windows box using rdp

rdp is the windows default and builtin "Remote Desktop Protocol".
with rdp you can connect to a remote windows machine, login to it with your username and password and use it almost like if you were sitting in front of it. so that one allows logging in - the only problem is it doesn't allow simultaneous usage from remote and directly by someone sitting in front of the pc.

to use rdp at your windows box (explaination for win7) you have to:

open the start menu
List item
right-click "Computer"
select properties
select remote settings
check the box "Allow Remote Assistance..."
select the radio box "Allow connections from computers running any version..."

at the linux box, you'll have to install a client like "remmina" which will allow you to enter the computer name of your windows box to connect to it.