How to connect wifi network from raspberry pi 2 (snappy)

So I just received my Raspberry Pi 3 Model B in the mail and installed Ubuntu Snappy Core 16 in the recommended way. I performed the initial setup via HDMI and usb keyboard, ethernet, & DHCP. Then I created my ssh connection over ethernet and disconnected the monitor and keyboard. From there, I wanted to connect my device to WiFi and stumbled upon this post.
I like to try things without extra installations or workarounds, so I consulted Installation Tips as recommended above and saw that WPA_Supplicant was supposed to be pre-installed. With very little meddling and less effort than the Tips suggested, I found that you can configure the wifi by simply adding a config file consisting of four lines to the default location searched by wpa_supplicant and nothing else. Though it was asked a while ago about a Raspberry Pi 2 I see from recent comments that it might still be relevant and it was so simple I am inclined to share.
I know this answer looks long, but it is very simple and detailed with pictures. Anyone who has a basic knowledge of Terminal and was able to set up their raspberry Pi initially will be able to follow it.

Tl;Dr

Setup your Rasberry Pi and establish a LAN connection via SSH
Shutdown your Raspberry Pi with sudo shutdown -P now
Plug your SD card into a linux distro
In a text editor add a config file called "wpa_supplicant.conf" to the /writable/system-data/etc/ folder on the Writable partition of the SD card
I did this by creating the conf file on my desktop and then using sudo cp to move it to the correct directory
The config file should be:network={ssid="Typhon Secure" Use your network SSIDpsk="*******" Use your network Passkey}
Note: This works for Hidden Networks as well
Eject your SD, plug it into your Pi, boot your Pi; it should connect to your WiFi

My tutorial begins from the point of having an ssh connection via ethernet, which can be achieved by following the instructions at Ubuntu Core Get Started Raspberry Pi 2/3.

Then type wpa_supplicant and you will see that it does not need to be installed as it is pre-built into Snappy Core. As you'll see in the below images, just running wpa_supplicant will return a lot of options, but notice the last line:
wpa_supplicant -Dnl80211 -iwlan0 -c/etc/wpa_supplicant.conf

What this tells you is first the Driver, then the Interface, then the location that it is looking for the interface file: -c/etc/wpa_supplicant.conf

Now that I knew where the configuration file needed to be, I shutdown the Raspberry Pi with sudo shutdown -P now and once it shutdown; disconnected the power and inserted the SD into a linux box with Fedora. Somehow the file system shows differently so you'll find the location where wpa_supplicant.conf needs to be location is at writable/system-data/etc and the SD card mounted in /run/media/cregger/ for me, so you'll see my file path is /run/media/cregger/writable/system-data/etc/.

I used nano to create a new file called "wpa_supplicant.conf" with the following four lines:
network={
ssid="Typhon Secure" (My network SSID)
psk="*******" (Obviously the asterisks represent my WiFi passkey)
} Don't forget to terminate.
Note that this works for hidden networks with no extra configuration. My network has a hidden SSID and I changed nothing. It has WPA-PSK 2 security; pretty standard fare.

You'll notice that I saved it to the desktop. I then copied it to the proper location with terminal as it is owned by root.

Then eject your SD card from Linux, plug it back into your Raspberry Pi, plug your power source back into your Raspberry Pi; let it boot and it will seek your wifi.
You'll see in my case both Eth and Wlan have taken an IP

I can now ssh via either LAN or WLAN

I know this was long, but I hope it was helpful in helping you to keep from mucking up your FS and installing a bunch of needless applications.


Put your arguments for the linker after instead of before your other arguments to gcc:

ek@Ilex:~/source$ gcc -lreadline read_test.c
/tmp/cc1IuVNQ.o: In function `main':
read_test.c:(.text+0xe): undefined reference to `readline'
collect2: error: ld returned 1 exit status
ek@Ilex:~/source$ gcc read_test.c -lreadline
ek@Ilex:~/source$ ./a.out
enter text>foo
text: foo ^C


At the initramfs prompt, type fsck -f /. Repeat if there are errors. Once done, type exit and reboot the computer.

If that doesn't work for you, we'll do it the old fashioned way...

boot to a Ubuntu Live DVD/USB
open a terminal window
type sudo fdisk -l
identify the /dev/XXXX device name for your "Linux Filesystem"
type sudo fsck -f /dev/XXXX # replacing XXXX with the number you found earlier
repeat the fsck command if there were errors
type reboot

Update #1:

Turned out that the BIOS had reset the SATA controller to RAID. (thanks @GabrielaGarcia). We reset it back to AHCI, did a fsck to verify proper disk operation, and the system is working again.


ok, the crash makes the text file look like binary file, use grep and answer from this question:
https://serverfault.com/questions/328101/how-do-i-grep-through-binary-files-that-look-like-text


Installing Ubuntu 10.10 / Windows 7 dual boot confusion

If you had multiple linux partitions and you don't remember the content per device names you will need to manually mount them and verify the contents.
Boot from the live cd with the "try it without installiing" option, then launch a terminal and check the list of partitions:

sudo fdisk -l

Example output:

   Device Boot      Start         End      Blocks   Id  System
    /dev/sda5           72947       76593    29294496   83  Linux
    /dev/sda6           76594       80240    29294496   83  Linux

Checking the contents of /dev/sda5 :

sudo mkdir -p /media/sda5
sudo mount /dev/sda5 /media/sda5
gksudo nautilus /media/sda5


Is there a simple way to install L2PT VPN in Ubuntu 14.04 x64?

I am the author of the VPN setup scripts at https://github.com/hwdsl2/setup-ipsec-vpn

What error(s) did you encounter? Please follow the instructions for Ubuntu and Debian under the "Installation" section of the repo's home page.

Added on 01/10/2016:
If you get Error 809 when connecting to an IPsec/L2TP VPN server in Windows, try making a one-time registry change to enable connections to VPN servers behind NAT. Here is the registry key to add:

For Windows XP:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IPSec

RegValue: AssumeUDPEncapsulationContextOnSendRule

Type: DWORD

Data Value: 2

For Windows Vista, 7, 8, 10, and 2008 Server:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PolicyAgent

RegValue: AssumeUDPEncapsulationContextOnSendRule

Type: DWORD

Data Value: 2

You must reboot the computer after creating this registry key.

Sources:
https://documentation.meraki.com/MX-Z/Client_VPN/Troubleshooting_Client_VPN#Windows_Error_809
Also see Microsoft KB: support.microsoft.com/en-us/kb/926179


For the most part, Linux is engineered in a fashion that makes it hard
  for viruses to run. However, there are many reasons you might want a
  virus scanner on your Linux PC:

  to scan a Windows drive in your PC
  to scan a Windows-based network attached server or hard drive
  to scan Windows machines over a network
  to scan files you are going to send to other people
  to scan e-mail you are going to forward to other people
  some Windows viruses can run with Wine.
  Linux virus infections are theoretically possible.1

For full detailed information Visit Ubuntu Documentation

1Source:Ubuntu Documentations


What drivers do I need? How do I install them?

The problem is that the latest fglrx drivers doesn't support 2XXX - 4XXX graphic cards models. Then, the only way I found that may makes the driver working is using fglrx-legacy from this repository: https://launchpad.net/~makson96/+archive/fglrx

The command line steps are these:

sudo add-apt-repository ppa:makson96/fglrx
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install fglrx-legacy

Although, you can install it manually using the official package: http://support.amd.com/us/gpudownload/linux/legacy/Pages/legacy-radeon_linux.aspx

If you want to install them with the package from AMD (recommended), you can use this guide: What is the correct way to install proprietary ATI Catalyst Video Drivers (fglrx) directly from AMD?


Ok, removing wayland stuff and rebooting helped. It has eaten the splash screen however (fix for splash: plymouth-theme-ubuntu-gnome-*, reinstall plymouth-theme-ubuntu-logo, plymouth-theme-ubuntu-logo).


Using OpenVPN on Ubuntu Mate 16, Network Manager for DNS. My PC has developed a mysterious new DNS leak

Thanks guys.

@Norbert. I'll try that out, looks interesting.

I actually found my solution after digging into related posts on the right. Which lead to this:

https://bugs.launchpad.net/ubuntu/+source/openvpn/+bug/1211110

Post #92 providing the solution. It worked!

Seems it's a long running problem.

@heynnema

Not sure to go with google's nameservers or my VPN provider's. Using the solution above, before seeing your post, I've set my VPN providers. Might stick with that, as my eggs are already in their privacy basket, if you know what I mean. But I guess there might an advantage to using Google's I'm not aware of.

Quite what broke my DNS lookup in the first place I might never know, I guess, but I assume it was probably some update to Network Manager. That's the second time NM's messed up my internet, last year it took out my wifi stick with it's MAC spoofing update. Very frustrating.

I guess changing my update settings is an unrelated problem. That's another puzzle to be solved.

I assume before things went wrong that my VPN provider was providing the DNS via the IP address of their VPN service, and that's what NM was using to get the DNS.

Could really do with a monitor of DNS leaks in software to do the job that ipleak.net and the like provide, so you know quickly when things have gone wrong by an alert.

Still have to hunt out a solution to auto-reconnect to the VPN.

Thanks guys.


Get downloadable applications that can open a specific file type

PackageKit allows you to search for applications by mime-type. Sadly, the Ubuntu devs haven't put much effort into integrating PackageKit with Ubuntu by default, but it still works surprisingly well.

First, make sure you've installed the graphical toolkit for PackageKit, gnome-packagekit-tools .

Then, run gpk-install-mime-type on the command line, followed by a mime-type. For example:

gpk-install-mime-type text/plain

Screenshots:


Now is possible with manual provisioning:

https://jujucharms.com/docs/stable/clouds-manual


Upgrading Ubuntu will require reinstalling Matlab and mtrack?

I have no experience with running mentioned software on Ubuntu but my overall experience is following:

There is basically no need for reinstalling a software after system upgrade unless it gets unmet dependencies. In that case you’ll need to upgrade such software. This may happen to Matlab as it is not installed using APT. However, Matlab R2016a supports Ubuntu 14.04 and not 12.04 (thanks @edwinksl for the link), so you should upgrade Ubuntu before installing Matlab if you’ve done none of these changes yet. Ubuntu 14.04 LTS has been out for 2 years already and should be mature enough.

If the installed software or users have made any changes to system configuration (/etc mostly), Ubuntu installer will ask if you wish to keep, overwrite or merge such changes. This will probably happen to the configuration of MTrack.


quickly package --extras replaces developer email with hostname

It's my understanding that it gets pulled from setup.py If you go to the bottom of that file, you'll see some fields which describe your project:

###################### YOU SHOULD MODIFY ONLY WHAT IS BELOW ######################
##################################################################################

DistUtilsExtra.auto.setup(
    name='foobar',
    version='12.07.28',
    license='GPL-3',
    author='Foo Bar',
    author_email='foobar@example.com',
    description="Here's my short description",
    long_description="Here's a a more detailed description",
    url='https://www.example.com/foobar',
    cmdclass={'install': InstallAndUpdateDataDirectory}
    )

If that's not working correctly, I'd make sure you have the DEBEMAIL environmental variable exported in your ~/.bashrc file:

export DEBFULLNAME='Foo Bar'
export DEBEMAIL='foobar@example.com'


Be more specific. That could have a 100 causes. What do your logs say? What do the sound preferences say? Does your soundcard show in the device list? Is the problem limited to a few applications or a certain filetype / pysical output on your pc? Have you upgraded your system or is it freshly installed? Does the pulsaudio-daemon run?

I'm taking a wild guess here and say: It doesn't work in Amarok only. If so install libxine-gnome.


How do I find running programs that are not visible?

Do you have your "Notification Area Applet" in your panel? that's the place where all the applications goes when minimized to tray or closed while running (as in the case of banshee, rhythmbox and many more).

I would also suggest you to have the "Indicator Applet" http://launchpad.net/indicator-applet in order to have a different tray for having useful applications at the reach of a clic.

This applets can be added to your panel, by right clicking on it and choose "Add to Panel", then simply identify those applets that you need, and drag them to the panel.

Give this a chance and please let us know if this helps.


How do you set up a vpn for Ubuntu 18.04.2 LTS

I found it but am still having a little trouble
https://protonvpn.com/support/linux-vpn-tool/


I can't do a complete upgrade in 14.04 due to LXC 2.0.3 related packages

If the packages are held back but other ones are updated, It's normal. apt-get update never change any package only update the installed packages. I asssume that you have installed lxc packages from backports or ppa. So you have two options:

Wait that the packages are updated in backports/ppa.
apt-get dist-upgrade. this command replace any package that you have installed for equivalents, uninstalling older ones. With care, because only in extreme cases atp-get dist-upgrade only uninstall older ones and don't install equivalent packages.


Just follow the instructions, and post your question if you have one.

http://mosquitto.org/download/

Instructions taken from the Mosquitto website.

Ubuntu

As of version 11.10 Oneiric Ocelot, mosquitto will be in the Ubuntu repositories so you can install as with any other package. If you are on an earlier version of Ubuntu or want a more recent version of mosquitto, add the mosquitto-dev PPA to your repositories list – see the link for details. mosquitto can then be installed from your package manager.

sudo apt-add-repository ppa:mosquitto-dev/mosquitto-ppa
sudo apt-get update

If the command “apt-add-repository” is not recognised, it can be installed with:

sudo apt-get install python-software-properties

Then mosquitto can be installed with:

sudo apt-get install mosquitto


Boot-repair Boot Info: dual boot Windows 8 and Ubuntu

I renamed grubx64.efi into EFI\Boot\bootx64.efi. Now everything is ok. As I understand it, some models of Sony VAIO use only the bootx64.efi boot loader.


How to create a Snap package that uses Docker to pull and run a Docker images?

Found the following dockerized-app-snap repository on GitHub which really helped me to create a Snap that run a dockerzied app through the content-interface shared by the docker snap.

Attached my snapcraft.yaml for anyone who trying to do something similar:

name: my-app
version: '1.0.0'
summary: |
  my-app Summary
description: |
  Some my-app Description.

grade: devel
confinement: strict

plugs:
  docker-cli:
    interface: docker
  docker-executables:
    content: docker-executables
    default-provider: docker
    interface: content
    target: docker-env

parts:
  environment:
    plugin: dump
    source: ./src/
    organize:
      'docker-wrapper' : bin/

apps:
  my-app:
    command: docker-wrapper docker <any docker command ps/pull/run>
    plugs: [docker-executables, docker-cli]

You can find general explanation on Snap Interfaces(plugs and slots) here
In short, an interface consists of a connection between a slot and a plug. The slot is the provider of the interface while the plug is the consumer.
In my case, the docker snap has 2 interfaces that it provides(slots) which my-app consumes(plugs) - the docker interface under the docker-cli plug and the content interface under docker-executables plug.

Regarding the question if Docker must be installed via Snap. Because my-app snap uses the docker snap interfaces, the answer it yes. But I'm not sure if it's conflict with a docker installed on the machine. will update when I have the answer.

Hoped I helped somebody!


Ubuntu automatically logs on to guest account

Please type this in the terminal and tell me what you get:-

whoami

Maybe you can try adding another account by below commands:-

sudo useradd newusername
sudo passwd newusername


Continue Ubuntu 14.04 LTS upgrade after stalled midway

The upgrade manager will not download a package twice unless you have issued an apt-get clean first. So yes, restarting the upgrade manager will pick up where it left off


The easiest way to do this is to add your NAS to your file dialog. From there you will be able to access your NAS directories. To do this you need to bookmark the directory in the NAS for the filemanager to remember the location.

Browse to the directory in the file manager, then bookmark it:

How to add custom links in the left pane of Nautilus?

Now when you go to wetransfer.com and click the upload button the file dialog will have the right bookmark on it, click on it, select the file, and that should be it.

To make this work permanently follow these instructions:

How to create a Bookmark that opens a Network shared folder


Copy pictures recursively from one folder to the root of another?

This will copy (will, echo) all the files that the file command thinks is some kind of image:

for i in $(find . -type f -print0 | xargs -0 file | grep " image " | cut -d: -f1 ) ; do echo cp "$i" $PWD; done


Your configuration should be OK, as the recommended minimum requirements are:

2 GHz dual core processor
4 GiB RAM

To be safe, you should try first Ubuntu with a live CD. If you're convinced then you can install it on your laptop.
If not, you may want to use a lightweight alternative, like Xubuntu or Lubuntu, which will definitely suitable to your config.


Dell Inspiron 15 3000 hotspot not working

In order to create a wireless network that other computers can connect to, you need a minimum of 2 wireless adapters, you can get another one by buying a usb dongle, they are usually pretty cheap, around 7 dollars. Once that's done you can follow this tutorial:

http://ubuntuhandbook.org/index.php/2014/09/3-ways-create-wifi-hotspot-ubuntu/

Hope this helped!


How to resume download during apt-get install

There is no "resume" feature in apt-get (according to man apt.conf)  nor does dl.google.com support ftp (which would allow you to manually resume)

So the best you can do is:

to manually download the package from another location (work?) and then cp /mnt/usb /var/cache/apt/archives
set the apt-get time-out to a higher value by gksudo gedit /etc/apt/apt.conf.d/99apt.conf and entering the following lines into it:

Acquire::http::Timeout "10";

Acquire::ftp::Timeout "10";

If the above doesn't make any sense, drop me a note @Fabby.


LibreOffice Draw

most of the distributions now come with LibreOffice
if you haven't, follow this link:
How to install LibreOffice 5.0 in Ubuntu?


Linking CXX executable RemoteZynAddSubFx

ZynAddSubFX links to these libraries and they are a hard-dependency as outlined in the build tutorial (see the Or, manually: block).

apt-get install libxft-dev libxinerama-dev


Screen problem with ATI drivers but not with X.org in 14.04

I had the same problem as you mate. I also have ATI Radeon 8600M on my Dell laptop. I came up with two workarounds for this problem that I will describe, so you do not have to bang your head.

I know what I am going to propose you is not direct solution for the problem. It is the best workaround that I have found so far from my experience. I will be very happy if someone manages to solve the problem the proper way.

I have searched all over the internet for a proper solution, but I could not find one.

I have discovered that the source of the problem is deep into the LightDM locker and the fglrx drivers. There is some conflict that I could not tarce down and did not find any solution. Evrytime I close the Lid of my laptop and it suspend, after I open it up I see either black screen or the system freezes completely or my screen showed only color lines.

First soltuion that I have tried and it worked was to remove LightDM and replace it with xscreensaver. And it worked - no more black screens or freezes after suspend.

To remove light-locker and install xscreensaver, execute this in terminal:

sudo apt-get purge light-locker light-locker-settings
sudo apt-get install xscreensaver

But for me xscreensaver looks very ugly, so finally I have uninstalled Xubuntu and installed Ubuntu 14.10. I have no problems with unity so far.

The other solution is to remove fglrx, and use xorg opengl drivers. I found that if I am using this driver the problem does not occurs. But I needed fglrx to run wine games so that was not solution for me ...

If you can not unsintall fglrx can you open the terminal and type:

sudo apt-get purge fglrx*

Paste any error output in you question.


Touchpad/Bluetooth mouse not working un Lenovo Yoga 720-15IKB in Ubuntu 16.04, Kernel 4.13

I also managed to install Ubuntu on the yoga 720 and wrote a thorough install guide.

To get the touchpad running you have to install a newer kernel, at least the kernel 4.14-rc5 (4.14 will be released in November 2017).

I installed the latest kernel with this script and got the touchpad running, but then at first the networking will be broken due to a bug in the apparmor settings, you can fix this by

sudo apt install apparmour-utils
sudo aa-complain /etc/apparmor.d/sbin.dhclient

(source: https://unix.stackexchange.com/questions/397708)


How do I create a shortcut for task manager in Lubuntu?

Make a backup of ~/.config/openbox/lubuntu-rc.xml for safety.

Open ~/.config/openbox/lubuntu-rc.xml with leafpad or with nano or any other plain text editor.

Search for this code:

<!-- Launch task manager on Ctrl + Alt + Del-->
<keybind key="C-A-Delete">
  <action name="Execute">
    <command>lxsession-default tasks</command>
  </action>
</keybind>

Very carefully, change lxsession-default tasks to lxtask.

Save the file (and exit the text editor if you want).

Open a terminal and run openbox --reconfigure. If you've done everything correctly (and if you haven't already messed up the file), you should just get back the terminal prompt.

Now, when you press CtrlAltDel, the task manager should open.


Why nova threadgroup cannot access database (nova-network)? "Can't connect to MySQL server"

By default, mysql only accepts connections from the local host.

Look in your /etc/mysql/my.cnf (on the controller node) for the following line and comment it out or change to allow connections in your applicable subnet.

bind-address            = 127.0.0.1

changes to (or you can remove it)

#bind-address           = 127.0.0.1

Then restart mysql server

user@openstack-ctlr:~$ sudo service mysql restart


“The system is running in low-graphics mode” Error. Solutions won't work,

I just reinstalled it. That fixed it for me...


I can login to my server through the terminal, but can't get in through Mac network

Not sure if you have configured this already, but Samba does not use the system password for your user.
You need to set one with sudo smbpasswd -a username
More information on configuring samba on Ubuntu can be found here: https://ubuntu.com/tutorials/install-and-configure-samba#4-setting-up-user-accounts-and-connecting-to-share


sound - sorry!, but can't get sound on fresh 14.04 install

Try running the console-based program alsamixer, and make sure nothing is muted (which is indicated by two capital M's located just above the level indicators at the bottom). Press m to toggle mute.

If that doesn't help, try running alsamixer -D pulseand making sure that isn't muted either.


apt-get install pavucontrol

This is a GTK volume mixer for pulseaudio

In contrast to classic mixer tools this one allows you to control both the volume of hardware devices and of each playback stream separately.

https://freedesktop.org/software/pulseaudio/pavucontrol/


How can I shut down the system from command line without sudo?

The privilege to shut down or restart without root is managed by ConsoleKit.

While the mechanism for how this works is changing as a result of systemd and logind, sending the following ConsoleKit message should still work to shut down without root:

/usr/bin/dbus-send --system --print-reply --dest="org.freedesktop.ConsoleKit" /org/freedesktop/ConsoleKit/Manager org.freedesktop.ConsoleKit.Manager.Stop


Won't decrypt home folder, Ubuntu server 11.04

Run ecryptfs-mount-private. It should be doing this automatically but until you can work out why it isn't, that should unlock your home, once you have logged in.

As for the actual issue, I've no idea why it's only running intermittently.


Which file descriptors (/dev/fd/##) are used in process substitution?

Videoprocessing is wellknown for seeking into the file. That means that you cannot use a stream as input. And if you are using output from another program, then it is a stream - no matter whether you use pipes or fds.

But maybe you are in luck that your program can use pipes. In that case this should be fine:

my_program --input1 <( {video transcoding command 1} ) --input2 <( {video transcoding command 2} )

The <() may look as if it is giving you something on stdin just like < does. But it does not. Instead it is substituted with a link to the pipe:

$ echo <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true) <(true)
/dev/fd/63 /dev/fd/62 /dev/fd/61 /dev/fd/60 /dev/fd/59 /dev/fd/58 /dev/fd/57 /dev/fd/56 /dev/fd/55 /dev/fd/54 /dev/fd/53 /dev/fd/52 /dev/fd/51 /dev/fd/50 /dev/fd/49 /dev/fd/48 /dev/fd/47 /dev/fd/46 /dev/fd/45 /dev/fd/44 /dev/fd/43 /dev/fd/42 /dev/fd/41 /dev/fd/40 /dev/fd/39 /dev/fd/38 /dev/fd/37 /dev/fd/36 /dev/fd/35 /dev/fd/34 /dev/fd/33 /dev/fd/32 /dev/fd/31 /dev/fd/30 /dev/fd/29 /dev/fd/28 /dev/fd/27 /dev/fd/26 /dev/fd/25 /dev/fd/24 /dev/fd/23 /dev/fd/22 /dev/fd/21 /dev/fd/20 /dev/fd/19 /dev/fd/18 /dev/fd/17 /dev/fd/16 /dev/fd/15 /dev/fd/14 /dev/fd/13 /dev/fd/12 /dev/fd/11 /dev/fd/10 /dev/fd/9 /dev/fd/8 /dev/fd/7 /dev/fd/6 /dev/fd/5 /dev/fd/3 /dev/fd/4 /dev/fd/64 /dev/fd/65 /dev/fd/66 /dev/fd/67
$ ls -l <(true)
lr-x------ 1 tange tange 64 Nov 12 07:59 /dev/fd/63 -> pipe:[1200523]

So you may be in situations where this makes sense:

$ cmd 2> >(cmd2) | cmd3


Storing files in the partition containing OS

Sounds like a permissions issue. You can see the permissions of a directory by right clicking properties or in terminal.

user@computer / $ ls -al
total 128
drwxr-xr-x  24 root root  4096 Mar 19 17:09 .
drwxr-xr-x  24 root root  4096 Mar 19 17:09 ..
drwxr-xr-x   2 root root  4096 Jan 15 17:27 bin
drwxr-xr-x   3 root root  4096 Mar 30 07:47 boot
drwxr-xr-x  17 root root  4300 Apr  3 22:24 dev
drwxr-xr-x 164 root root 12288 Apr  4 12:31 etc...

In the example above all the directories are owned by root. Chown the directory you would like to store the files in replacing  with your username

$ sudo chown -R <your username> /path/to/dir

This will give you ownership of the directory so you can paste into it. The -R makes the change recursive so the ownership of sub directories are also changed.


First, you my be misunderstanding the purpose of apt-fast.  It's not something for slow network connections, it's something for fast network connections.  If you have a slow connection to the Internet, you are not reaching the bottleneck of the repository and will not benefit by pulling from more than one repository simultaneously.

If you have a fast Internet connection, faster than the repositories, then you could benefit by pulling from more than one repository at once.

More directly to your question, did you run the sudo apt-get update after adding the repository?

In between asking the question I tried the repository on a test machine and it appears to be broken (for ubuntu/trusty 14.04).  What error did you get when you tried to update the repository?

Alternatively, with the apt-fast repository broken you can use the github.

You might also communicate the broken (or unavailable 14.04) repository to the apt-fast support team.

With the knowledge that you can't benefit from it on a machine with a slow Internet connection might be a factory in how much work you want to invest in installing it on your computer.


Is there a way to open an "extra" temporary workspace?

The script below allows you to keep two different sets of worspaces. If you place the script under a shortcurt key, you can toggle between the two sets:

normal workspaces -

extended workspaces -

How to use

Copy the script below into an empty file. In the head section, define the "normal" situation in rows / columns:

normal = (2, 2)

and the "extended" situation you'd like to see in rows / columns:

extended = (2, 4)

Save the script as manage_workspaces.py. Test if it does want you want it to do by running the command:

python3 /path/to/manage_workspaces.py

When you run the command, the workspace setup should toggle between the two sets, and a message should appear in the notification area (see the pictures above)
If all works well, add the command to run the script to a shortcut key of your choice:
Choose: System Settings > "Keyboard" > "Shortcuts" > "Custom Shortcuts"
Click the "+" and add the command:

python3 /path/to/manage_workspaces.py

The script:

#!/usr/bin/env python3

import subprocess

# default situation rows / columns
normal = (2, 2)
# extended set of workspaces
extended = (2, 4)
# commands to read the current state
key = "/org/compiz/profiles/unity/plugins/core/"
read_hor = "dconf read "+key+"hsize"; read_vert = "dconf read "+key+"vsize"
hor = int(subprocess.check_output(["/bin/bash", "-c", read_hor]).decode("utf-8").strip())
vert = int(subprocess.check_output(["/bin/bash", "-c", read_vert]).decode("utf-8").strip())
# take action, depending on current state
if (hor,vert) == normal:
    set_h = "dconf write "+key+"hsize "+str(extended[1])
    set_v = "dconf write "+key+"vsize "+str(extended[0])
    message = "notify-send 'set to extended workspaces: "+str(extended[0])+" x "+str(extended[1])+"'"
else:
    set_h = "dconf write "+key+"hsize "+str(normal[1])
    set_v = "dconf write "+key+"hsize "+str(normal[0])
    message = "notify-send 'set to normal workspaces: "+str(normal[0])+" x "+str(normal[1])+"'"
for item in (set_h, set_v, message):
    subprocess.call(["/bin/bash", "-c", item])


How do I disable systemd-resolved and replace with something sane on Ubuntu 18?

You can always disable your systemd-resolved by
systemctl disable systemd-resolved.service
command. And run:
sudo rm /etc/resolv.conf && sudo ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
to use /etc/resolv.conf config as it was earlier in previous ubuntu versions.


BIOS does not detect SSD after reboot from ubuntu 16.04 (Dell XPS 15)

I was having the same issue on my Dell XPS 15 9550 using kernel 4.16; after a lot of research I found a solution that works for me:

TLDR: Boot with kernel parameter nvme_core.default_ps_max_latency_us=4950

I do this by modifying GRUB_LINUX_CMDLINE_DEFAULT in /etc/default/grub and then running sudo grub-install.

The Issue

As Cristian Velasquez Ramos posted earlier in this thread, a quirk that disables APST (Autonomous Power State Transition) for the NVMe Samsung 950 (Firmware ID: BXV76D0Q) was merged into mainline kernel 4.11.0rc7 to fix bugs such as these:

Discussion from the linux-nvme mailing list:

  Samsung 950 series SSDs in Dell XPS 15 9550 and Precision 5510    laptops (which are essentially the same laptop) can lose their PCIe
  link if they're allowed to use the deepest APST state.    Samsung
  engineers have an affected system and are working on    it.  The same
  exact SSDs in other machines (even an XPS 13)    seem to work fine.

Because of this quirk, the default APST controller state is set to off for our device, which causes the issues with soft reboot we were seeing.

Here's the discussion about the quirk that was merged into mainline
4.11:

We need to disable the quirk somehow in order to fix the issue with soft reboot.

We can entirely disable the quirk by using nvme_core.force_apst=1, but this can cause the bugs with read/write after extended usage (it happened for me after 3 days of uptime). Because of this, simply overriding apst will not work.

However, we can disable the lowest power state by using the kernel parameter:
nvme_core.default_ps_max_latency_us=4950

This fixes all issues!
Thanks again to Cristian Velasquez Ramos for the fix.


Problem while installing ubuntu with ATI Radeon 6670 HD

Welcome Muhammad

You could try editing the install options and change "quiet splash" with nomodeset, this should inhibit the installer loading a graphics driver which causes your problem. I'm not sure the details but I had to use this once when I installed ubuntu and you can find details in forums. It appears to be a bit of a dark art!

There is an alternative installer which I read is text base, Ive never used it perhaps someone can confirm this?

I found a similar problem here for boot but I assume it's driver problem and it should work too.

Black screen on boot


Copying (usb drive to usb drive) suddenly slowed down. Ubuntu Server 12.04

I found another post which suggested it might have something to do with automounting the drives. I disabled the usbmount package which I use to automount the USB drives at boot and mounted them in the terminal. It worked!


Install Teamviewer on Ubuntu 17.04 with 64-bits architecture

Step by step guide how to install Teamviewer on 64-bit architecture running Ubuntu 17.04

Step 1

Download the deb package from Teamviewer Website

Step 2

In a terminal, type:

sudo dpkg --add-architecture i386
sudo apt update
sudo apt install -y libc6:i386 libgcc1:i386 libasound2:i386 libdbus-1-3:i386 libexpat1:i386 libfontconfig1:i386 libfreetype6:i386 libjpeg62:i386 libsm6:i386 libxdamage1:i386 libxext6:i386 libxfixes3:i386 libxinerama1:i386 libxrandr2:i386 libxrender1:i386 libxtst6:i386 zlib1g:i386

Step 3

Now you can either run the downloaded .deb file by double-clicking it or run it in the terminal by typing:

dpkg -i /path_to_your_download_folder/downloaded_file.deb

Note:
I did not test on previous releases of Ubuntu, some dependencies may vary but the overall process remains the same.
If you have any comments or remark, please feel free to improve!


Cannot ping localhost after a half day of uptime

I was able to fix this issue on my Debian machines by upgrading to the 3.2.0-4 kernel currently in Wheezy from the 2.6.32-5 currently in Squeeze.

If you're unable to update your kernel, I've been able to work around this issue on two of my servers by telling them to access the local DNS resolver over IPv6 instead of IPv4. Here's my resolv.conf:

search example.com
nameserver ::1

It hasn't been a perfect work around, but it was sufficient for a while.


If You didn't get Your php as Ubuntu package You may need repository for the latest php version:

sudo apt-add-repository ppa:ondrej/php
sudo apt-get update

Then follow the package You are interested in, for example:

sudo apt-get install php7.1

Remember to use sudo when needed as George suggested.


Why can't two interfaces belong to the same subnet?

The wording "in Linux, the IP address belongs to the host and is not associated with the interface" is not fully correct. Actually, in Linux IP address is associated with the interface, but kernel's TCP/IP stack responds to any known IP address on any interface. So if you have for example two interfaces, 10.0.0.1 connected to network 10.0.0.0/16, and 192.168.0.1 connected to network 192.168.0.0/16, then if you ping 10.0.0.1 from any device on the network 192.168.0.0/16 (of course assuming that routing is set so that it directs these packets to 192.168.0.1), you will get a reply from the interface 192.168.0.1 claiming to be from 10.0.0.1, even if the IP forwarding is not turned on in the kernel.
Therefore, if two interfaces are connected to the same subnet, you can never know which one will respond. The same applies for ARP requests, as ARP requests are send by broadcast to all interfaces in the subnet asking "who has IP address a.b.c.d?". Either interface will recognize this address as it's own and either may respond.


unable to dualboot win XP with Ubuntu 13.04 on Asus Zenbook UX32a

I never trust automatical tools, like Boot Repair. This question is fine example of why do they not deserve my trust. I've seen many ways of how one can manually do the things that BR does. Steps you should perform:

Boot from LiveCD/LiveUSB
Launch Terminal: Ctrl+Alt+T
Run:

sudo su
mount /dev/sdb1 /mnt
grub-install --root-directory=/mnt /dev/sdb
for i in /sys /proc /run /dev; do mount --bind "$i" "/mnt$i"; done
chroot /mnt
update-grub
exit
umount /mnt/dev /mnt/proc /mnt/sys /mnt/run /mnt
exit

Reboot, enter your BIOS and check that you boot from /dev/sdb

After that, your Ubuntu should start without problems.

Also you may refer to:

Source if you experience problems with my way
UEFI How-To if you need to disable Secure Boot feature.
Dual booting on separate drives in case if you have any questions left.


Sublime text - no shortcuts working on non-latin layout, 12.04

As a temporary workaround you can simply open and then close a new tab in Sublime.
After that some hotkeys are starting to work.


Those aren't the files on your USB, those are the devices attached to your system (sda, sdb, sdc are disks, sda1 is the partition 1 of disk 1 and so on)

If you want to see the contents of your usb you must locate it there (or use lsblk command) and mount it for example with:

sudo mount /dev/sdc1 /mnt

Where /dev/sdc1 is your device / partition and /mnt is your mountpoint.

Once you have the mountpoint (in this case /mnt) you could list the files in it by doing one of the followings:
ls /mnt or cd /mnt && ls

Read more at: http://manpages.ubuntu.com/manpages/gutsy/en/man8/mount.8.html


Brother HL printer seemingly installed, but not printing

Try this:

Download the tool: http://download.brother.com/welcome/dlf006893/linux-brprinter-installer-2.0.0-1.gz

The tool will be downloaded into the default "Download" directory, e.g. /home/UserName/Download

Open a terminal window: Press Ctrl+Alt+T

Go to the directory you downloaded the file to in the last step:

cd /home/UserName/Download

Enter this command to extract the downloaded file:

gunzip linux-brprinter-installer-2.0.0-1.gz

Get superuser authorization with the sudo command:

exec sudo -i

Run the tool:

cd /home/UserName/Download
bash linux-brprinter-installer-2.0.0-1 HL-L2340DW

The driver installation will start. Follow the installation screen directions.

When you see the message "Will you specify the DeviceURI ?",

For USB Users: Choose N(No)
For Network Users: Choose Y(Yes) and DeviceURI.

The install process may take some time. Please wait until it is complete.


Does running dd if=/dev/zero often can damage the drive?

dd is not a low level format, it's just writing all zeroes to the entire disk. A low level format would be like running ATA Secure Erase. Additionally, there are also an even lower level format to modify the sector/cylinder definitions that you really don't want to go to.

Running dd on entire disk shouldn't damage the drive. It would increase the wear and tear since HDD contains moving parts, but modern HDD are pretty long lived that this shouldn't really matter in practice.

If by "hard drive" you actually mean SSD though, do note that SSD suffers from wear and tear much more than HDD. The SSD memory cells will wear out faster if you do lots of writes. Additionally, writing to entire SSD is essentially pointless in SSD due to wear leveling. I'd recommend using full disk encryption if you're using SSD, and to format you can simply discard your decryption key. ATA Secure Erase on SSD usually is implemented with encryption this way.


Can't install libc6 due to multiarch problems on Ubuntu precise

Got this fixed somehow with the following steps:

aptitude download libc6

mkdir tmp
dpkg-deb -R libc6_2.15-0ubuntu10.17_amd64.deb tmp
# edit DEBIAN/preinst replaced 'dpkg-query -L libc6' with 'dpkg-query -L libc6:amd64'
dpkg-deb -b tmp libc6_2.15-0ubuntu10.17fixed_amd64.deb

dpkg -i libc6_2.15-0ubuntu10.17fixed_amd64.deb

Now I was able to resolve the conflicts. To get rid of all i386 packages I used now:

dpkg -l | grep :i386 | awk '{ print $2 }' | xargs dpkg -P

and now it seems I have got rid of the i386 packages:

dpkg -l libc6
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                                                  Version                         Architecture                    Description
+++-=====================================================-===============================-===============================-===============================================================================================================
ii  libc6:amd64                                           2.15-0ubuntu10.17               amd64                           Embedded GNU C Library: Shared libraries


External hdd boot entries added to GRUB after upgrade to 13.10

You can resolve your issue simply by removing the laptop's hard drive from your desktop (if it is still attached) and issuing the following command in Terminal:

sudo update-grub

Voila! You should now be ship shape! :)


Problems with nvidia drivers on Dell XPS

The XPS series (without 3D) have two graphics units. An Intel onboard chip and the Nvidia chip. The Nvidia gpu is activated and disactiviated depending on load by software within the Windows driver called Optimus. NVidia has not choosen to release this for Linux yet.

On my XPS 17 I am simply not running any NVidia drivers at the moment and Ubuntu is working great. I will take a look at
https://github.com/z0rc/debumblebee
when I have a chance. This should give some of the same functionality as Optimus.


Most distro vendors will make their own build from source for open source software. In this case Ubuntu has a branch of OpenJDK sources which I are kept up to date with CVE and other bug fixes. You can look at the commit history here.
They might mix and match whatever patches are neccesary on their branch.
So to answer your question it appears that ubuntu provides its own build of OpenJDK which likely pulls patches for bugs and security vulnerabilities from upstream as may be necessary.


I have the same problem and this was printed:

lo        no wireless extensions.

eth0      no wireless extensions.

The main problem was that I didn't check the "Install third party stuff" when my Ubuntu was installing. So I ran the following command:

sudo software-properties-gtk

Went to Additional Drivers tab and checked to use any proprietary driver I want.

Source: http://www.upubuntu.com/2012/10/to-do-list-after-new-installation-of.html


If you're just interested in remapping keys in a manner that works for any wm, I think I have a way for any typical X wm but you would probably have to configure it per wm.  For example, in Awesome, I add the following line to the end of my rc.lua:

awful.util.spawn_with_shell("/usr/bin/setxkbmap -option caps:swapescape -option altwin:ctrl_win")

with my other autostart items.  The above options will swap escape and capslock and map the "windows" keys (and the usual ctrl keys) to ctrl.

Whatever DE or wm you use, it should offer a way to autostart commands.  Autostarting the appropriate setxkbmap command  should remap your keys.  I've done this in various window managers.  AFAIK, this is the reliable, "proper" way to remap keys, in contrast to xmodmap, which seems flakey.

To remap the keys you want, you need to know the appropriate options and key values to pass.  You can find a list in /usr/share/X11/xkb/rules/xorg.lst

Of course, you could use setxkbmap in .xinitrc also, but as you pointed out, lightdm doesn't seem to use it when loading the sessions.  Since I use lightdm too, I don't usually think of editing xinitrc, but it just struck me that there should be a way of starting a user-defined X session through lightdm... and I found this answer.  That might be more in line with what you want to do.


What is the difference between /etc/network/interfaces and /etc/config/network

It has a difference:

/etc/config/network

This configuration file is used by netifd (Network Interface Daemon) mostly used in OpenWrt distributions.

/etc/network/interfaces

This configuration file is used by ifup (including ifdown and ifquery) utility.
In other hand, distributions like Ubuntu, Debian use the NetworkManager
daemon which manages network interfaces, connections in a flexible way.

If you want to use ifup instead of NetworkManager, you should configure NetworkManager not to manage interfaces used in /etc/network/interfaces.


Problem with stuttering video - 16.04 & Nvidia 390

What drivers are you using for the 1050Ti? try one from ppa:graphics-drivers/ppa
or you can do sudo apt remove nvidia* or sudo apt remove ubuntu-drivers then reinstall it.


Normally Broadcom wireless drivers are restricted in ubuntu. You can install it using the additional driver utility.
System->Administration->Additional Drivers.

Just active your driver in that application.


The system logs are restricted to root for security reasons.  Learn to use sudo.  (Or for a singleuser system where you're reasonably confident about security, you can change the permissions on the log files yourself.)


How to make grep grab the first hit instead of the last

You can do this using PCRE mode (grep -P) by using the Perl non-greedy modifier ?:
$ printf '%s\n' 'hello this is a test hello this is a test' | grep -Po 'hello.*?test'
hello this is a test
hello this is a test


Menu for hibernate does not work, pm-hibernate does

Since you say you can use pm-hibernate without any problem, it means there is no issue in your hibernate setting. Therefore, the problem should be in the settings of menu button. Again, you have mentioned that you are following the same setting which was prescribed here.

As per my understanding, and regarding the fact that you have been facing with this right after upgrading to Ubuntu 15.10, I think your system needs a new configuration for the button. Go through these steps:

Remove the content of /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla and restart you system. Now any configuration for the hibernate button should be removed from the system.

After booting up, open the file again and paste those few lines mentioned in the link into the file and save. Restart your system again.

If everything goes properly, the button should be configured for Ubuntu 15.10


Openstack: juju-gui col-location with cinder

Main thing to check for is IP port conflicts; if the juju-gui is on 80, and your machine0 has something on port 80, they will conflict. Otherwise, should be no problem, it's common to stick the Juju GUI on a side machine :)

In future we'll serve the Juju GUI straight from the Juju server.


Well, turns out that resolution check is only at startup. Once VCMI is up and running I can just revert to native resolution. VCMI takes care of scaling all on its own, by drawing to fill while keeping aspect ratio.
This gets rid of all problems with mouse and touchscreen.
# disable external screen
xrandr --output HDMI-1 --off
# force 800x600 resolution
xrandr --output DSI-1 --mode forced600
# after 10 seconds reset to standard resolution
( sleep 10; xrandr --output DSI-1 --mode FIXED_MODE --scale 1.0x1.0 ) &
# run game
vcmiclient

However it sadly results in game being letterboxed.
TODO: get that touchscreen working with display scaling...
TODO: figure out how to right click on touchscreen...


How to stop Cairo Dock minimizing Conky on Show Desktop?

Use:

own_window_type panel

using panel instead of normal or override should fix your problem, i.e. keep your conky window visible through show_desktop function calls from cairo dock (or other programs)

See below extract from the conky documentation for other settings:

from:   http://conky.sourceforge.net/config_settings.html

  if own_window is yes, you may specify type normal, desktop, dock,
  panel or override (default: normal). Desktop windows are special
  windows that have no window decorations; are always visible on your
  desktop; do not appear in your pager or taskbar; and are sticky across
  all workspaces. Panel windows reserve space along a desktop edge, just
  like panels and taskbars, preventing maximized windows from
  overlapping them. The edge is chosen based on the alignment option.
  Override windows are not under the control of the window manager.
  Hints are ignored. This type of window can be useful for certain
  situations.


Try one of the terminal-based text editors.

Nano  (sudo nano /path/to/file)
Vim   (sudo vim /path/to/file)

Your favorite search engine will happily show you many tutorials on how to use either editor. Both take a couple minutes to learn (especially how to save your work and exit!)
The ability to edit files using a terminal is spectacularly useful, and easily worth the few minutes invested to learn. For many of us, it's an essential job skill.


Trying to move/merge ext4 partitions with win7 partition intact

Boot the live medium, go to gparted - you will probably have to right click on the swap and swapoff. If the extended and swap have padlocks next to them they are mounted - swapoff will deal with that.

Then you will be able to move the extended to the left to include the unallocated space. Then uou can create a new logical inside the extended and format it.

However I would not do that - I assume that sda2 is your ubuntu install.

I would delete the swap, then the extended and then create a new extended using all of the unallocated space, create a NEW swap with size 2.5Gb and then a new ext4 partition with the remaining space.

Much quicker - now all you need to do is change the swap reference in your fstab

Close gparted.

Open a terminal and run

sudo blkid

Make a note of the UUID you get against the swap partition.

Mount your install so you can edit it

sudo mount -t ext4 /dev/sda2 /mnt

Open the file for editing

gksudo gedit /mnt/etc/fstab

Look for the swap line and change the UUID to suit, I put my swap UUID and fstab line below for reference

/dev/sda8: UUID="9237bdd4-1976-4532-9c6f-558fb7b4a6f5" TYPE="swap"

# swap was on /dev/sda7 during installation
UUID=9237bdd4-1976-4532-9c6f-558fb7b4a6f5 none swap sw   0       0

Your fstab shows

/dev/sda5 none swap sw 0 0

Edit that so it is

UUID=yourUUIDnumber none swap sw 0 0

Once done - save and exit.

You can check that the swap is being used

sudo swapon -a
free -m


You should create a Live USB version of Ubuntu before you boot into the Elementry OS installer since I'm not sure if the disk tools needed are present in that distro. Once booted choose "Try Ubuntu" instead of "Install" to enter the "Live" mode and run either gnome-disks or gparted and resize your existing partition creating free space then when installing Elementry OS they should give you an option to use existing free space on the disk.


What driver should I pick for my GPU, and what are the differences?

I am asking this because my GPU keeps crashing (Also on windows)

This indicates that the problem is unlikely to be software after all.  Why do you conclude that it is the "GPU" that crashes?  Did you look into kernel logs or the X server logs?

I would suspect it could be a hardware problem, including a faulty graphics card, motherboard, power supply, or memory errors.  Replace the graphics card, and then run whatever system tests the BIOS gives you (or boot into the memtest option, if you have that).

And fix the broken packages, either cycle apt update and upgrade, or apt remove all the problematic packages and then reinstall the correct driver package.


is it true that Chromium uses more cpu than firefox?

Chromium will use more memory then Firefox as the amount of tabs goes up (this is by design).
While running Chromium press Shift+ESC to bring up the chromium task manager. Click the 'Stats for Nerds' button and see which process in Chrome is using the most memory. You can use this to check what memory is used.
A few graphs from Tom's hardware "Web Browser Grand Prix 9: Chrome 17, Firefox 10, And Ubuntu"

We use the Internet's Top 40 Web sites (according to Quantcast) for our memory and page load reliability testing. Unlike our startup and page load times, this test uses live sites; the test sites are not hosted on our local Web server.
Chrome's memory usage is measured through its about:memory flag, while the other browsers are measured with the Windows Task Manager/Ubuntu System Monitor. Each browser is opened with the Google homepage as the only tab. Memory usage is recorded, and then the additional 39 tabs are loaded. Once all tabs report as loaded, we inspect each page for broken elements and reload any pages that have not opened properly before recording the 40-tab memory usage.
Next we close all tabs except the original one containing Google's homepage and re-record the memory totals. Finally, we wait two minutes and record the final memory usage figure.

This test is from 2012 but the numbers still seem to stand. The only thing this does not cover is the usage of HTML5.
Conclusion

Overall, Internet Explorer and Chrome are the winners during periods of light usage. They also seem to manage memory best. Safari and Firefox shine more prominently during heavy loads. Chrome and IE9, however, are hogs when it comes to heavy use, and Opera for Linux demonstrates poor management.

My opinion:
Stick with the browser you -like- and works for your.


how to get curl -X POST command to output the http status 200 or else?

This command

curl --head \
     --output /dev/null \
     --write-out "%{http_code}\n" \
     --silent \
     -X POST https://api.primotexto.com/v2/notification/messages/send

will fetch the header only, redirect the output to /dev/null, silence any progress bars, and eventually print the http_code (200).

If you instead want to print the content of the website alongside the HTTP returncode, then a simple --write-out "%{http_code}\n" will do:

curl --write-out "%{http_code}\n" \
     -H "…" \
     -H "…" \
     -d "…" \
     -X POST https://api.primotexto.com/v2/notification/messages/send

Output:

<!DOCTYPE …>
…
<html>…</html>
200


Can I setup an SVN server on Ubuntu One?

No, you can't.

At some point we thought of adding a WebDAV backend to the file sync service, and that would be a step towards being able to do svn, but it never got much traction.

  Ubuntu One is not a backup service, so if you were wanting to use it for that, please disabuse yourself of the notion; there are many things that make up a good backup service, and we provide none of them, and we probably never will. People are building a backup service on top of ours, namely the deja-dup guys are doing that and that's awesome, but that's something else.

Why not use launchpad?


No Bluetooth on Intel 7265 WLAN card (Dell XPS 13)

Not all Intel 7265 wifi cards have bluetooth, those that do will have a BDM(bluetooth MAC address) along with a WFM(wifi MAC) printed on the sticker that is on the card.

The picture shows an example of an Intel 7265 wifi with bluetooth


Errors encountered while processing linux-image-5.3.0-18-generic

As shown with the above two comments, contents of /etc/default/grub on line 36/37 were the source of the issue. This problem has now been solved. Possibly user error on my part OR juts something strange when I setup the system originally (did not use the default installer for all steps, partitioning was done manually in terminal and grub-install was run after installation with the contents of the LVM virtual group manually mounted)

Will set this as the 'answer' in 2 days as stack exchange won't let me do it now


How to change the "search statements" in Unity lenses?

Yes you can do it.

get the source code of the application.
Find and change the text with one you want.
compile and build the application.
uninstall previous lens and install your self compiled one.


Where is hadoop-ec2-env.sh in the Hadoop packages?

This is a partial answer that needs more investigation by someone who's deployed Hadoop before.

It seems that those instructions are out of date, I tried both 1.0.x and 1.1.x debs and neither have the file src/contrib/ec2/bin/hadoop-ec2-env.sh.

However there is a /etc/default/hadoop-env.sh file that has environment variables in it, no clue if this is the right place to put the AWS credentials though.


Resizing images keeping the same pixel ratio

This can be done from terminal.  How to Quickly Resize, Convert & Modify Images from the Linux Terminal:

ImageMagick will try to preserve the aspect ratio if you use this
command. It will alter the image to fit within a 200×100 area, but the
image may not be exactly 200×100. If you want to force the image to
become a specific size – even if it messes up the aspect ratio – add
an exclamation point to the dimensions:
convert example.png -resize 200×100! example.png

You can also use GIMP.

GIMP is expandable and extensible. It is designed to be augmented with
plug-ins and extensions to do just about anything. The advanced
scripting interface allows everything from the simplest task to the
most complex image manipulation procedures to be easily scripted.

Source: http://docs.gimp.org/en/introduction.html
To install GIMP, you can run
sudo apt-get install gimp


How to connect to a WPA2 enterprise with nmcli in a non interactive mode?

Kind of a late response, but maybe someone stumbles upon this same problem and may be looking for a solution.

Proper Solution

EDIT: Looks like I was wrong with both solutions, since I happened to get exact same error. However I found a solution to this - simply set all 802-1x settings in one line, e.g.:

nmcli c modify <connection_name> 802-1x.eap <eap_mode> 802-1x.identity <username> 802-1x.phase2-auth <auth_type>

For what I've tested, these 3 settings are a minimum to setting 802-1x property. I will leave the previous answer, for I believe these still might be applicable as part of the solution.

Previous Solution (for reference)

This looks like you are trying to set wifi-sec.key-mgmt connection property before setting 802.1x values. To put it simplier, you must put your edits in specified order, with 802.1x settings first, and wifi-sec keys later.

However, if that is not the case - do you have your connection already added? You can add an empty template using following command:

nmcli con add type wifi [ifname <interface_name>] [con-name <connection_name_shown>] [ssid <ssid_of_wifi_connection>]

All parts (not sure about con-name) in [] can be skipped, but you would need to add them through modify command later on for the network to run, unless you only have 1 WLAN interface.


Ubuntu default sudo session is 15 minute (may change with different version) but you can change it . Run and open

sudo visudo

and change line :

Defaults    env_reset

to

Defaults   env_reset,timestamp_timeout=20

It will not ask for 20 minute. if you do 0 then it will ask every time and
if -1 then it will never prompt for password for sudo session.


refresh rate of monitor resets to 60hz after each reboot

Did you launch the nvidia tool with super user privileges?

I had a similar issue where the tool launched as a normal user did not issue any error at saving time, but the saving was incomplete because of access right.

Launching the tool with super user privileges solved my problem.


Ubuntu installed on Vmware cannot get access to internet

Selecting NAT option under Network Connection in Network Adapter setting has done the trick for me.


Running out of space on hard drive, want to upgrade to ssd

The answers provided in this question: How to move Ubuntu installation from one hdd to another? may be useful for you. Of which I will reproduce here my own answer for your convenience.

  Clonezilla may be useful for cloning your hard disk, even for those situations on which you need to do it with different size disks
  as mentioned here:
  http://www.tuxradar.com/content/how-clone-hard-drives-clonezilla

    Moving to a bigger disk

    It's easy to ensure that a clone of a SCSI
    disk is restored to a SCSI disk, but you'll have a tough time finding
    an exact replica size-wise. The good news is you don't have to restore
    a disk on another disk of the same size. The even better news is that
    you can in fact restore the image to a much larger disk.

    When restoring a disk, Clonezilla enables you to resize the filesystem
    and create partitions on the new disk proportionally. But even if you
    are moving to a bigger disk, you might prefer to keep the partitions
    as they are. In that case you can ask Clonezilla to create the
    partition table as its listed in the image.

  There is documentation about moving to a larger disk as mentioned here
  but I am not sure that you can do it the opposite (cloning to a
  smaller disk).

  However, it's worth to try. Clonezilla offers several Live CD's and
  bootable USB images and there is also documented that you can resize
  the free space on the disk after the copy, in which case the
  suggestion by @maniat1k to use gparted is also a good idea.

  If you use clonezilla, I would appreciate if you drop comments with
  your experiences over here in order to have well documented how does
  this work for future reference.

I hope this help you.

Good luck!


Ubuntu need at least a primary partition to work. Besides that swap is advisable if you use memory consuming programs. And needed if you want to put the computer in hibernation. If you install Ubuntu it will automatically set up the needed partitions for you when you choose "Install Ubuntu alongside windows".


usb read-only in gui, but works fine from terminal (12.04)

This was solved by formatting as ntfs & running ntfs-config and then re-booting. Rebooting was not mentioned in the post that suggested this, and I just hadn't tried that yet (although I tried reboot between all the previous steps. Sorry I missed this.)


It should work.

Some applications will store absolute pathnames in their configuration files or in other files they keep. You will have to change those manually or set up the user-specific parts of the application again.

You can search for these files as follows (at least the ones that store the pathnames as text):

find /home/new_username -type f -exec egrep -H '/home/old_username' {} \;

That command won't fix the files. It will only find them for you. You could use sed to change the files. Something along the lines of:

find /home/new_username -type f -exec egrep -l '/home/old_username' {} \;|xargs sed -i 's%/home/old_username%/home/new_username/;g'

Please test first.

Note that some files might seem to be text files, but actually are binary files. Doing a search-and-replace on these files can break them.

Note: You don't need to use chown -R new_username:new_groupname /home/new_username to transfer ownership of the files in the new home directory to the new user, because the UID for the "new user" is the same as for the "old user", so then the files are already owned by the "new user".


Run these commands in the terminal:

sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 40976EAF437D05B5
sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 3B4FE6ACC0B21F32

This downloads the missing GPG keys (as mentioned in the original error message) from the Ubuntu GPG keyserver.


Make router use Dns Server of PC inside Lan

You'll need to actually confirm your assumption that the router is looking outside the LAN for the DNS server.  Confirming what you think here is tricky.  When you don't have a router you can do a full packet trace on, it's nigh impossible.

Effectively, though, your router is only getting those DNS servers so it can then later provide them to the machines inside via DHCP.  This is because for the most part DNS lookups occur at the endpoint client/machine/workstation level, not the router unless your router has a DNS forwarder which forwards DNS lookups outbound.  As such, the computers themselves will rely on the IP address as given.  The router is smart enough to know that the IP address is in the internal LAN subnet (there's programmed logic to know what the RFC-dicated private network ranges are instead of public and bogons), and will send it to that internal instead of externally to the Internet.  However, the IP destination for the DNS packet is determined for the most part at the endpoint machines internally instead of the router.

You should be able to alter the DHCP settings at the router so the machines connected to the router will automatically get the DNS server entry for the internal machine instead of the ISP servers.  From there, you should be able to test if your internal DNS is working as it should be.  It never hurts to keep the ISP (or if you're paranoid, Google) DNS servers as backups on the endpoint machines in case your bind server doesn't work.


For Ubuntu 12.04.2, the kernel is /casper/vmlinuz.efi. Notice the .efi was added in recently.

Also, you don't need to extract the CD files, you can boot directly from the .iso. Here's a template I use for USB multiboot:

menuentry "YOUR TITLE" {
    insmod ntfs
    insmod iso9660
    loopback loop /distros/FILENAME.ISO
    linux (loop)/casper/vmlinuz.efi persistent boot=casper iso-scan/filename="/distros/FILENAME.ISO" noeject noprompt splash toram --
    initrd (loop)/casper/initrd.lz
}

This way I can keep all distros/versions as their pristine .iso files in a /distros directory inside the NTFS data partition. Grub2 is installed to the MBR, and its /boot files (including the above handwritten /boot/grub/grub.cfg) also in the data partition. Grub2 was installed as:

sudo grub-install --no-floppy --root-directory="/PATH/TO/MOUNTED/USB" "/dev/sdX"


Searching through the repository I found colorname that seems to do what you want.

sudo apt-get install colorname

Using the eyedropper select a color then click Execute at the bottom, and it attempts to find the closest match from several color databases (Gimp, Wikipedia, X11).


Middle mouse button click will paste the highlighted text into the terminal (or wherever you can enter text).

For more detailed information on Multiple Paste Buffers see geirha's answer in this question.


Get Quotes for stock prices in GnuCash using Finance::Quote

The GNUcash mailing list helped me to resolve this issue. My answer to the same question can be found on superuser.stackexchange here

(Perhaps these questions should be merged.)


Can the Applications or Files and Folders buttons be moved on the Unity Launcher?

Yes but they need to be within their group and files&folders and applications are 1 group. So you can put files&folders above or below applications. There are a few other launchers that are added to this group like the askubuntu (askububtu.place), google books (books.place) etc.

Basically we currently have 2 groups (hold the 'super' key while reading this and look at the launchers): digits and letters. And you can change the order of the group with digits and the group with letters.

Those digits and letters  are inside all the *.place files on your system.

For instance /usr/share/unity/places has 3:
applications.place  books.place  files.place

$grep Shortcut *

applications.place:Shortcut=a
books.place:Shortcut=b
files.place:Shortcut=f

(Ofcourse changing the =a to =11 did not add applications to the other group so it will be something inside the Unity system the takes care of this...)


Error while installing .net core 2.0 sdk in ubuntu

SDK version and link depends on your ubuntu version you have to choose correct one in the list. But if you use 18.04 you have to follow these commands

# NO_PUBKEY EB3E94ADBE1229CF
sudo apt-key adv --keyserver packages.microsoft.com --recv-keys EB3E94ADBE1229CF

# NO_PUBKEY B02C46DF417A0893
sudo apt-key adv --keyserver packages.microsoft.com --recv-keys 52E16F86FEE04B979B07E28DB02C46DF417A0893

sudo sh -c 'echo "deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-ubuntu-bionic-prod bionic main" > /etc/apt/sources.list.d/dotnetdev.list'

sudo apt update
sudo apt install dotnet-sdk-2.1.300-preview2-008533

From Github issue


SqlServer error installation on Ubuntu WSL?

It's a reported bug on Windows, which is yet to be fixed.


What is the equivalent of an "exe file"?

I would summarize the system in the following way:

Linux extension    |Windows Equivalent    |Short description
------------------------------------------------------------
.so, .o            | .dll                 | Object that can be loaded at runtime (Similar to DLL)
.a                 | .lib                 | Static library
[none], .elf(rare),| .exe, .com(rare)     | Linux executables
  .bin(rare)       |                      |
.sh                | .bat                 | Shell script
.exe               | .exe                 | Mono application, Wine application
.deb               | .msi                 | Installer package for Debian/Ubuntu releases
                   |                      |   (Though .deb is much more powerful with
                   |                      |   native support for dependencies and repos). Note that .deb is actually a .ar archive with a special control file, a special file order, and a different extension.
.rpm               | .msi                 | Installer package for RedHat/CentOS releases.
.tar.gz, .tar, .gz | .zip                 | Compressed files that can contain a program or any other data, like images, documents, etc
.ko                | .sys                 | Drivers and kernel modules are loaded into the Linux kernel and have more hardware access than other programs.
.sh, .php, .py, etc| .bat, .cmd, .vbs,    | Linux is capable of running any file that it has an interpreter for.
                   |   .js                |   A line at the top of the file called the shebang specifies what interpreter to run the file with.
                   |                      |   Windows only supports .bat and .cmd files as Batch files, and .vbs (vbscript) and .js (JScript, not to be confused with JavaScript) via the Windows Script Host (WSH).

Any file that starts with #!(called a shebang or hashbang) on the first line is just a script. The path after the shebang is a path to the program (executable) that needs to parse the script, assuming that the execute permission has been set on the file with chmod a+x filename.

Therefore,  answer your original question, there is no extension, or rarely, it is .elf or .bin.

This has been made Community Wiki, so anyone can add an entry.


Unable to download packages from local cosmic repository

Found this post where he used the following:

deb [arch=amd64 trusted=yes] file:///home/discoprodigy debbin/

Modified my sources.list:

deb [arch=amd64 trusted=yes] http://127.0.0.1/ubuntu cosmic main restricted universe multiverse

Looks like adding architecture and trusted fixed the problem.


Similar 'freezes' are often due to MTU size. Aren't you by any chance going through VPN connection ? Try to change MTU size to 1300 and see if it helps.
I use screen on RPi with Ubuntu 16.04, no problem reattaching.

To change MTU size use sudo ip link set dev vpn0 mtu 1300


How do I get newest version of adobe flashplayer?

Other way is to go to Ubuntu Software Center and install Flash Player plugin.


Mr. Evans, start here:

https://help.ubuntu.com/lts/serverguide/samba-ldap.html

Both Samba and LDAP require solid beginnings. You really need to know what you want to achieve before going forward. They can be confusing topics.


I could fix it running:

pvchange --uid /dev/sda5


Screen and Mouse Freeze - no way out - lubuntu firefox

If the screen and mouse are the only things that have locked up, maybe you can use the keyboard to switch to a text console and then kill the offending process that is clogging up the system.

In Linux, CTRL-ALT-F1/F2/F3/etc are typically the control keys used to switch from console to console. In the old days, CTRL-ALT-F7 was typically where the graphical X11 console resided at, but now a days in Ubuntu 18.04, CTRL-ALT-F1 or sometimes CTRL-ALT-F2 is typically where I see the GUI on my machine. The other CTRL-ALT-Fx keys have text consoles.

BTW, some versions of Linux seem to only respond to the left hand CTRL-ALT buttons. I just tried my Ubuntu 18.04 and it seems to let me switch consoles with either side CTRL-ALT-Fx keys. YMMV.

Once you're at a text console, login and you'll be dropped into a command line terminal. From there, you can use commands to try to find the offending process and kill it:

ps ax
kill -9 XXXX

(replace XXXX with the process ID number obtained from "ps ax")

You could also find the "top" command useful for seeing if there is a process that is stealing 100% of the CPU cycles or taking up more RAM than available.

If you know the name of the process you want to kill, you could use "ps ax | grep firefox" for example, to make it easier to find the exact process ID number than scrolling through the entire list of processes. That little vertical line character is the "pipe" character, which is typically found on your keyboard by pressing SHIFT and the "\" key.

Good luck to you!


wait for dd command to fully write to the disk

Despite popular belief, dd is a perfectly ordinary command, it isn't more low-level than cat or cp. Your command reads from the disk cache and writes to the disk buffers like any other command.

In order to make sure that the data is fully written to the physical media, you need to call sync. The command sync flushes all output buffers to the disk(s). When the sync command returns, the data has been fully written.

sudo dd if=~/Desktop/ubuntu.iso of=/dev/sdx bs=1M; sync

Most of the time, you don't need to call sync, because unmounting a filesystem does the same job. When the umount command returns, or when you get a confirmation message after clicking “Eject”, the buffers have been written to the disk. Here, you're directly writing to the disk without going through a mounted filesystem, so you need to explicitly flush the buffer.

Note that instead of dd, you could use tee. This has two advantages: there's less risk of inverting the source and destination due to a typo, and it's probably slightly faster.

<~/Desktop/ubuntu.iso sudo tee /dev/sdx >/dev/null; sync


Thinkpad X1 Yoga: accelerometer Acer BMA150 not working

This device is used for harddisk shock prevention, and its detection as a joystick is an error. You get this error message because testing a non-joystick with the joystick tester doesn't work for obvious reasons.

To get it to work, at least on other thinkpads, you can install hdapsd. It needs to be run as a daemon - it reads the accelerometer data and parks the hard drive heads when critical motion of the laptop is detected.

For newer devices, specifically yours, hdapsd doesn't support the hardware. You can install iio-sensor-proxy to test your laptop with it. Other Yoga laptops work with it, according to their Github page.


set window properties (above, on all workspaces) in js/gnome-shell-extension?

I asked this question of the gnome mailing list - turns out that the meta window properties are all read-only, so I can't (currently) set the above/on all workspaces options using mutter.

However, I can use a library wnck to achieve this. Whilst mutter is still preferred, this may be the only way for now.

Luckily wnck has gobject introspection, so this was sufficient:

const Wnck = imports.gi.Wnck;
let window = Wnck.Screen.get_default().get_active_window();
if ( window ) {
    window.make_above();
}

There are functions make_above, unmake_above, pin, unpin, stick, and unstick (although I don't know what the difference is between pin and stick), all listed here.


ImageJ can't find JVM although OpenJDK 8 is installed

This is a bug. It's Reported at launchpad here titled imagej won't start (xenial). Which is itself a duplicate of this bug, which says JAVA_HOME auto-detection fails due to whitespace in update-java-alternatives output

It is fixed in Debian and fixed version is included in Yakkety.

There are several fixes reported in the bug report. One fix that worked for me was manually exporting JAVA_HOME and starting from terminal

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64
imagej

Someone reported that a build of Yakkety works for Xenial too. It can be downloaded from here https://launchpad.net/ubuntu/+source/imagej/1.50i+dfsg-1/+build/9642507

I downloaded that build and it works without any workaround!

Another workaround is directly editing /usr/bin/imagej file as suggested by ByteCommander (Thanks to him). Around line 32, changing the line

JAVA_HOME=$(/usr/sbin/update-java-alternatives -l | grep openjdk | sort | tail -1 | cut -d' ' -f 3)

to

JAVA_HOME=$(/usr/sbin/update-java-alternatives -l | grep openjdk | sort | tail -1 | tr -s ' ' | cut -d' ' -f 3)

that is basically inserting tr -s ' ' | before cut ...


from manpage of Ubuntu for nmcli-examples https://manpages.ubuntu.com/manpages/focal/man7/nmcli-examples.7.html Example 14. there is a script to make Ethernet and Wi-Fi mutually exclusive
#!/bin/bash
export LC_ALL=C

enable_disable_wifi ()
{
    result=$(nmcli dev | grep "ethernet" | grep -w "connected")
    if [ -n "$result" ]; then
        nmcli radio wifi off
    else
        nmcli radio wifi on
    fi
}

if [ "$2" = "up" ]; then
    enable_disable_wifi
fi

if [ "$2" = "down" ]; then
    enable_disable_wifi
fi

   This dispatcher script makes Wi-Fi mutually exclusive with wired networking. When a wired
   interface is connected, Wi-Fi will be set to airplane mode (rfkilled). When the wired
   interface is disconnected, Wi-Fi will be turned back on. Name this script e.g.
   70-wifi-wired-exclusive.sh and put it into /etc/NetworkManager/dispatcher.d/ directory.
   See NetworkManager(8) manual page for more information about NetworkManager dispatcher
   scripts.

Make the new script executable: chmod a+rx /etc/NetworkManager/dispatcher.d/70-wifi-wired-exclusive.sh


My laptop wont boot from ubuntu installation disc

Try the following tricks:

When that violet screen and the logo appeared, hit space on the keyboard, then choose your own language. Check your disc first, 'cause DVDs are fragile media. if everything is ok. you can go back to that menu and choose install now. If it doesn't work,
Boot your windows up, insert your flashdrive, back it up, and use the Universal USB Installer. If it doesn't work:

Install VirtualBox on your windows, and load the image you've downloaded. use the internal usb boot creator to install ubuntu to your flashdrive. Since you are using a 64bit windows, you have to download the extension pack from virtualbox.org to support the usb module for virtual machine.

Well, that's all i can think of.


There are many, many ways to contribute to Ubuntu. Some require technical knowledge, but many do not.

Before contributing to Ubuntu, you should read the Ubuntu Code of Conduct, which lays out a standard of behavior for contributors.

(Mostly) Non-technical:

Perhaps the easiest way to contribute to the Ubuntu community is to provide support. Besides helping out friends and family, you can answer questions on IRC, the Ubuntu Forums, or on this exchange!

A new project that is looking for contributors is the Ubuntu Manual project. According to their website,

  Getting Started with Ubuntu is a complete beginner's manual for
  Ubuntu, featuring comprehensive guides, How Tos, and information on
  anything you need to know after first installing Ubuntu.

Their Get Involved page says they are looking for authors, editors, translators, programmers, and designers -- there's something for everyone!

Another project for writers is the Documentation Team. They write the documentation that comes with Ubuntu and work on the help wiki.

The One Hundred Papercuts project calls for users to submit bug reports on small usability problems (paper cuts). This requires almost no technical knowledge and has a direct affect on the Ubuntu experience.

Ubuntu strives to look good, and it takes artists to make that happen. Submitting art is an easy way to make a visual impact on Ubuntu. Check out the Artwork wiki page for information about that.

A really fun way to get involved is to join and participate in your Local Ubuntu Community (LoCo). You can check out the list of Ubuntu LoCos to see if there is an active community near you. If there is none, you can start one yourself!

As Javier Rivera commented below, multilingual users should look at contributing translations. Someone new to translations can get started with the Translations Quick Start Guide.

More Technical:

If you're the programming sort, there's plenty of room for you to pitch in. I'm not an Ubuntu developer myself, but the Developers page on the Ubuntu website is a good place to get started.

At the beginning of a new project called Operation Cleansweep, there were over two thousand potential bug fixes on Launchpad just waiting to be applied. This project works to review those patches and get them applied to their projects.

Conclusion:

There are innumerable ways to contribute. These are only just a few! Technical knowledge is helpful, but not absolutely necessary.


What is the best way to run .EXE files in Ubuntu 13.04?

Wine allows you to execute a .exe program if you select Wine as a default program for .exe files from Nautilus, open a .exe file using "Open with another application" and select Wine or you execute wine file.exe from terminal.


why is source command not being run in .bashrc

Are you launching your terminals with a login shell?

Does your ~/.profile or ~/.bash_profile contain . ~/.bashrc?

If you use gnome-terminal,

Edit -> Profiles
select your profile and click Edit
on the Title andCommand tab, check "Run command as a login shell"


I fixed it, by doing this:

Step one: uninstall the python-mode Ubuntu package. It was doing more harm than good, especially with the tabbing behavior.

Step two: add this line to my .emacs file:

(require 'tramp)

This got rid of the error, when calling M-x pylint, of thetramp-tramp-p function being missing. Apparently this is a bug in Ubuntu 14.04's copy of pylint.el, that has since been patched upstream (see this pull request).


How do I set a password for guest login?

The Guest Account exists as a created-then-destroyed-on-logout account that is limited in what it can do and exists without a password.  That is the purpose of a "guest account" - limited access, automatically-destroyed-on-logout.  It is not designed to run with a password.

You can create a "guest" account that you can keep as a normal user (not a guest user) by making a user named "guest" and setting a password on that, though, and then potentially restricting their access.  You can then disable the normal "guest account".  (The guest account system however will never have a password.)


Redirect audio to HDMI with XRandr to watch and hear movies

Ubuntu have pavucontrol, although you may need to install it using APT. This utility has the output device selection called Profile for some reason, on the last tab called Configuration which may also be confusing.


What is apache handlers equivalent in Lighttpd

It's lighttpd.conf and is stored in /etc/lighttpd. See this Tutorial Configuration - Lighttpd.


How can I add an item to the KDE Application Launcher Menu using the command line?

OK, for me what worked was:

Take the applications-kmenuedit.menu file generated the first time you do a save inside KMenuEdit, clean up the "bogus" entry (or whatever change needed to get KMenuEdit to actually save a file there), and then copy that into either /etc/xdg/menus or ~/.config/menus. Magic file: bah!


Edit ~/.vimrc and put these in it:

set autoindent
set tabstop=4
colorscheme default

Note: type :colorscheme and hit Tab in order to find available colorsschemes installed for your Vim .

To use vim as default editor, use this

export EDITOR=/path/to/vim or simply export EDITOR=vim

or you can save this in your rc file


Where should I install my tar.gz files like java or eclipse?

In general you do -not- install software using tar.gz files. These files are containers that hold software (that might contain software to install but normally you get is all done and ready for you to use). You use either Ubuntu software center or debian installer files to install software.

Eclipse: https://askubuntu.com/a/118377/15811
Java: https://launchpad.net/~webupd8team/+archive/java

So there should not be a need to use tar files for these 2 pieces of software.
But if you still want to continue with this: for these types of installations the advised location to extract tar.gz files is /opt/. The Filesystem Hierarchy Standard says:

/opt : Add-on application software packages
Purpose: /opt is reserved for the installation of add-on application software packages.


Apparently, it runs the service once, then upon reboot, it switches to a regular up status, i.e. if the service goes down, runit starts it back up again.


It's still there, but you do not have to press Ctrlf.  Just open the folder in question and start typing.

Ctrlf opens up another search dialogue where you can search inside folders and files.


You can install the nvidia driver from ubuntu software-center.

Open ubuntu software-center, click edit and select software sources. Click on Aditional Drivers and from there you can select the proprietary driver from the list of drivers. The most stable version is the one marked "tested".


Does Ubuntu 13.04 conclusively support TRIM?

Trim is supported, it is not enabled by defaulthere is a good guide
https://sites.google.com/site/easylinuxtipsproject/ssd


Ubuntu 14.04 liveusb boot screen graphic errors

I diagnosed the problem to be bootloader not being able to recognize the graphics mode for the laptop. And that it is forcing an unsupported one by default which should not happen. And ends up  drawing smaller screen.

I managed to work around the situation by adding/modifying a line in my bootable liveusb drive's /boot/grub.cfg :

set gfxmode=1024x768

This along with the nomodeset option allows me to boot with correct graphic settings. I can see the splash and try ubuntu with full(er) resolution now.

If you have similar issue, try setting the gfxmode yourself. And after installing ubuntu you would need proprietary graphic drivers and also nomodeset option to boot properly.


Open terminal and enter

sudo apt-add-repository "deb http://archive.canonical.com/ $(lsb_release -sc) partner"

then click enter to confirm

then enter

sudo apt-get update && sudo apt-get install skype

Skype is available in the partner repositories.

apt-cache policy skype
skype:
  Installed: 4.2.0.11-0ubuntu0.12.04.2
  Candidate: 4.2.0.11-0ubuntu0.12.04.2
  Version table:
 *** 4.2.0.11-0ubuntu0.12.04.2 0
        500 http://archive.canonical.com/ubuntu/ raring/partner amd64 Packages
        100 /var/lib/dpkg/status


Fixed it eventually. The linked question incorrectly referenced /etc/ldap.config, but should be /etc/ldap.conf.

I never found any detail logs, but pam_ldap seemed to at least confirm my issue by writing some errors to /var/log/syslog.


Adding icon to the system tray (notification area)

GtkStatusIcon is not supported in Unity.

If you need an icon displayed use Application Indicators instead. They are quite easy to handle but one drawback is that custom icons are not officially supported yet (see this question here), and that application indicators may not be available in other distributions.

In addition, defining custom icons as suggested here does not work in early versions of Application Indicators used in 10.04 LTS.

Therefore you may need that your program checks if Application Indicators are present, and in addition checks the version they have in order to get them running properly. If Application Indicators are not provided or if your application should also run in other distributions you can also use GtkStatusIcons. In this case you will have to program for both paths as was suggested here.

As far as I can see today GtkStatusIcons will still be supported when running classic GNOME Desktop in Ubuntu 11.04 but I don't know about GNOME3.