The Beta of the OpenStack Autopilot can deploy on up to 10 physical nodes before running into the limits of its built-in license.

You may contact Canonical sales to increase the number of managed devices, but this will only become possible after the public beta status for the product ends (we don't like to charge for "beta" functionality).

To be clear, the 10 free nodes will continue to be available even after the Beta period ends.


How to copy file to all clients using puppet?

The Puppet File Server

This guide covers the use of Puppet’s file serving capability.

The puppet master service includes a file server for transferring static files. If a file resource declaration contains a puppet: URI in its source attribute, nodes will retrieve that file from the master’s file server:

# copy a remote file to /etc/sudoers
file { "/etc/sudoers":
    mode => 440,
    owner => root,
    group => root,
    source => "puppet:///modules/module_name/sudoers"
}

All puppet file server URIs are structured as follows:

puppet://{server hostname (optional)}/{mount point}/{remainder of path}

If a server hostname is omitted (i.e. puppet:///{mount point}/{path}; note the triple-slash), the URI will resolve to whichever server the evaluating node considers to be its master. As this makes manifest code more portable and reusable, hostnames should be omitted whenever possible.

The remainder of the puppet: URI maps to the server’s filesystem in one of two ways, depending on whether the files are provided by a module or exposed through a custom mount point.

Serving Module Files

As the vast majority of file serving should be done through modules, the Puppet file server provides a special and semi-magical mount point called modules, which is available by default. If a URI’s mount point is modules, Puppet will:

Interpret the next segment of the path as the name of a module…
... locate that module in the server’s modulepath (as described here under “Module Lookup”...
... and resolve the remainder of the path starting in that module’s files/ directory.
That is to say, if a module named test_module is installed in the central server’s /etc/puppet/modules directory, the following puppet: URI...

puppet:///modules/test_module/testfile.txt

...will resolve to the following absolute path:

/etc/puppet/modules/test_module/files/testfile.txt

If test_module was installed in /usr/share/puppet/modules, the same URI would instead resolve to:

/usr/share/puppet/modules/test_module/files/testfile.txt

Although no additional configuration is required to use the modules mount point, some access controls can be specified in the file server configuration by adding a [modules] configuration block; see Security.

Serving Files From Custom Mount Points

Puppet can also serve files from arbitrary mount points specified in the server’s file server configuration (see below). When serving files from a custom mount point, Puppet does not perform the additional URI abstraction used in the modules mount, and will resolve the path following the mount name as a simple directory structure.

File Server Configuration

The default location for the file server’s configuration data is /etc/puppet/fileserver.conf; this can be changed by passing the --fsconfig flag to puppet master.

The format of the fileserver.conf file is almost exactly like that of rsync, and roughly resembles an INI file:

[mount_point]
    path /path/to/files
    allow *.domain.com
    deny *.wireless.domain.com

The following options can currently be specified for a given mount point:

The path to the mount’s location on the disk
Any number of allow directives
Any number of deny directives

path is the only required option, but since the default security configuration is to deny all access, a mount point with no allow directives would not be available to any nodes.

The path can contain any or all of %h, %H, and %d, which are dynamically replaced by the client’s hostname, its fully qualified domain name and its domain name, respectively. All are taken from the client’s SSL certificate (so be careful if you’ve got hostname/certname mismatches). This is useful in creating modules where files for each client are kept completely separately, e.g. for private ssh host keys. For example, with the configuration

[private]
   path /data/private/%h
   allow *

the request for file /private/file.txt from client client1.example.com will look for a file /data/private/client1/file.txt, while the same request from client2.example.com will try to retrieve the file /data/private/client2/file.txt on the fileserver.

Currently paths cannot contain trailing slashes or an error will result. Also take care that in puppet.conf you are not specifying directory locations that have trailing slashes.

Security

Securing the Puppet file server consists of allowing and denying access (at varying levels of specificity) per mount point. Groups of nodes can be identified for permission or denial in three ways: by IP address, by name, or by a single global wildcard (*). Custom mount points default to denying all access.

In addition to custom mount points, there are two special mount points which can be managed with fileserver.conf: modules and plugins. Neither of these mount points should have a path option specified. The behavior of the modules mount point is described above under Serving Files From Custom Mount Points. The plugins mount is not a true mount point, but is rather a hook to allow fileserver.conf to specify which nodes are permitted to sync plugins from the Puppet Master. Both of these mount points exist by default, and both default to allowing all access; if any allow or deny directives are set for one of these special mounts, its security settings will behave like those of a normal mount (i.e., it will default to denying all access). Note that these are the only mount points for which deny * is not redundant.

If nodes are not connecting to the Puppet file server directly, e.g. using a reverse proxy and Mongrel (see Using Mongrel), then the file server will see all the connections as coming from the proxy server’s IP address rather than that of the Puppet Agent node. In this case, it is best to restrict access based on hostname. Additionally, the machine(s) acting as reverse proxy (usually 127.0.0.0/8) will need to be allowed to access the applicable mount points.

Priority

More specific deny and allow statements take precedence over less specific statements; that is, an allow statement for node.domain.com would let it connect despite a deny statement for *.domain.com. At a given level of specificity, deny statements take precedence over allow statements.

Unpredictable behavior can result from mixing IP address directives with hostname and domain name directives, so try to avoid doing that. (Currently, if node.domain.com’s IP address is 192.168.1.80 and fileserver.conf contains allow 192.168.1.80 and deny node.domain.com, the IP-based allow directive will actually take precedence. This behavior may be changed in the future and should not be relied upon.)

Host Names

Host names can be specified using either a complete hostname, or specifying an entire domain using the * wildcard:

[export]
    path /export
    allow host.domain1.com
    allow *.domain2.com
    deny badhost.domain2.com

IP Addresses

IP address can be specified similarly to host names, using either complete IP addresses or wildcarded addresses. You can also use CIDR-style notation:

[export]
    path /export
    allow 127.0.0.1
    allow 192.168.0.*
    allow 192.168.1.0/24

Global allow

Specifying a single wildcard will let any node access a mount point:

[export]
    path /export
    allow *

Note that the default behavior for custom mount points is equivalent to deny *.


Installing Ubuntu 12.10 on my HP-Pavilion G6 Issues

I have a HP Pavilion G6 on which I am successfully stably running Ubuntu 12.04 LTS for over 18 months.  Before that I was not able to upgrade because the wireless "card" was not supported.  Audio was late in coming, as well; but once they were supported, I moved Windows over and installed 12.04 successfully.  I recently researched upgrading to 12.10 and decided against it due to the same factors--reports of a lack of drivers for the G6.  I would suggest you consider 12.04 if you are really interested in getting a stable installation.


What causes these error messages when trying to open LibreOffice Writer?

LibreOffice is looking for these two files and can't find them. All you need to do is create the files. It's ok for the files to be empty.

The easiest way to do this is to issue commands in the terminal.

Close LibreOffice.

Use Ctrl+Alt+t to open a terminal. In the terminal you can copy and past the following commands. To paste in the terminal, use a right click and choose Paste from the popup menu, or click the scroll wheel on your mouse. Press Enter after each command. Enter commands one at a time.

cd ~/.config/libreoffice/3/user/basic/Standard

Check to see if the files are already there.

ls

If the files are there, something else is causing the problem. If they are not there, you just need to create them.

touch script.xlb

and after Enter

touch dialog.xlb

Restart Libreoffice.


I'm not seeing anything in the man pages about being able to download. You may need to use wget if possible.

 wget -O /desired/path/name.zip http://someplace.com/file.zip

If you need to log into the site, just modify the wget command as follows

wget --user username --password pass -O /desired/path/name.zip http://someplace.com/file.zip

or it may be

wget --user username --password pass http://someplace.com/file.zip -O /desired/path/name.zip

Edit: Since you said it did not work, lets drop the output option (if you havent already). Does

 wget --user user --password pass http://serveraddress/file.zip

do it for you? Obviously changing "user" with your username and "pass" with your password.


I had the same problem. Here is what I did and it worked perfectly so maybe it would work for you. I just deleted the account and added it again. The Ubuntu did the rest  automatically for me (asked for email / login and password). Now it is working properly.


What is the "multiply/divide key" mentioned by the Ubuntu installer?

After a lot of Googling,I believe I understand it. The English keyboard with "toggle on multiply/divide key" is a legacy option to support the XO laptop from the One Laptop Per Child project. The layout is located in /lib/udev/keymaps/olpc-xo. Apparently, there were some hardware bugs with the keycodes on the XO. As a workaround on bilingual XO devices, the multiply/divide key (a key that existed on that device but is not a standard key on other devices) was used to to switch between keyboard layouts.

I installed the keyboard and it can be fairly useful if you type a lot of non-English characters, plus it has some useful combining diacritics. To insert the special characters, use System Settings > Keyboard Layout > Options to set the Compose key or an AltGr key.

Again, the multiply/divide key does not exist on standard devices, so the way to toggle between this layout and any other keyboard layout, such as US Dvorak, is through the same standard settings path above. Within Keyboard Layout Options use Key(s) to change layout to set a toggle of your choice.


What are the Spectre and Meltdown issues related to FF52esr?

SharedArrayBuffer is disabled by default on Firefox 52 ESR.

Firefox ESR 52.6.0 has been released. From blog post on Mozilla:

  performance.now() mitigations will be included in the regularly scheduled Firefox 52.6 ESR release on January 23, 2018.

Also see mfsa2018-03 security advisory.


You just need to run this command before

anbox session-manager


Find the properties of an mp3 file via command line

use the command

mp3info -p %a %t file.mp3

%a for artists
%t for track title

if mp3info is not installed in you system

sudo apt-get install mp3info


You may use PAE version of linux kernel to access more than 3.5GB of memory on 32-bit system.

For this, you need to install "linux-generic-pae" package either from synaptic or by issuing the following command in terminal:

sudo apt-get install linux-generic-pae

Details are described here: https://help.ubuntu.com/community/EnablingPAE

To check if your processor supports PAE cat /proc/cpuinfo | grep pae if it yields results you're good:

flags: fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36
clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx rdtscp lm constant_tsc
arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64
monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 x2apic
popcnt xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow
vnmi flexpriority ept vpid


Libinput enabling Tapping and twofinger scrolling Ubuntu 17.04

Accroding to archlinux manual, your lines should look like this:

/etc/X11/xorg.conf.d/30-touchpad.conf
      ...

 Section "InputClass"
 Identifier "devname"
 Driver "libinput"
 MatchIsTouchpad "on"
 Option "Tapping" "on"
 Option "ClickMethod" "clickfinger"
 Option "NaturalScrolling" "true"

...
EndSection

Bear in mind that some of them may only apply to certain devices.

Source:
https://wiki.archlinux.org/index.php/Libinput


check that your wireless is switched on go to "system settings" (in the right top corner where you also switch off) --> "network" and check the options for wireless
your wireless network might be hidden try to click on the network icon and connect to hidden networks
to check if your wireless adapter is working properly you can test it with "system testing" just choose the test you want to do (to come there just hit your windows key and type sys --> and the icon should show up)

hope it helps


You can install Ubuntu.

Recommended system requirements:

2 GHz dual-core processor or better
2 GB system memory
25 GB of free hard drive space
Either a DVD drive or a USB port for the installer media
Internet access is helpful

https://www.ubuntu.com/download/desktop


/bin/sh: 1: arm-linux-gnueabi-gcc: not found

You'll need the gcc-arm-linux-gnueabi package, rather than just gcc-4.4-arm-linux-gnueabi; the former supplies the arm-linux-gnueabi-gcc symlink.


Coolbits "1" does nothing (GTX 560ti, 310.14, Ubuntu 12.04)

You cannot use Coolbits to overclock Fermi based boards (such as the gtx560), it is not supported by the hardware. Your only alternative is to flash a custom firmware with a tool called nvflash (not available on canonical servers).

Even though a linux version of nvflash is available it is suggested to boot from a DOS box and use the dos version of the same tool. You can find a very exhaustive guide here BUT flashing a custom firmware is a very dangerous business (you may end up with a bricked video card) and I would discourage you from taking that route.


You need libglib2.0-dev for glib-gettext. You can install it with

sudo apt-get install libglib2.0-dev


Assuming this is a bios booting computer and not EFI, and that you partition each individual disk and create a raid type partition and use those partitions to build the raid array, then you install grub to each of the individual disks in the array so that any one of them can boot the system using any n-1 disks that are still present to access the array.  You can do this by running sudo dpkg-reconfigure grub-pc and checking all of the individual disks ( /dev/sda, /dev/sdb, etc ) to install grub to.

Note that the graphical standard installer will only allow you to pick one place to install grub to, so you either need to use the server installer, or manually run sudo dpkg reconfigure grub-pc afterwards to install grub to all of the disks.

Also do not forget that with a RIAD5, only two disks need to fail to render all of your data lost, and with 6 disks total that is not entirely unlikely.  If your concern is maintaining system uptime then you might want to use RAID6, which can tolerate two disks failing, but in any case, RAID is no substitute for backups, so either way, you still need to back up your data otherwise to make sure that you don't lose it should something go wrong, which it inevitably will.


Lenovo s10-3 Xubunutu wireless is disabled by hardware switch

Oh no. I've been there. There's only one solution. You have to either install windows and turn the hardware switch back on. Or the following, and this is what I did. You have to open your netbook and take out the battery to do a CMOS reset. Here's the tutorial I followed:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/577114/comments/31

It was also discussed here:
http://www.linlap.com/lenovo_ideapad_s10-3


Problem with encoders in Subtitle Editor

Open terminal and run the command:

sudo add-apt-repository ppa:mc3man/gstffmpeg-keep
sudo apt-get update
sudo apt-get install gstreamer0.10-ffmpeg


The solution mention here solved this problem.

sudo systemctl disable cups-browsed.service


"Shockwave Flash is known to be vulnerable" warning

Mozilla, which develops Firefox, imposed the block because recently
  unearthed bugs in Flash were being actively used by cyber-thieves.

  The bugs were detailed in a cache of documents stolen from security
  firm Hacking Team that was hit by attackers last week.

  Adobe said it took Flash's security "seriously" and was planning bug
  fixes.

Source

There is now no way to make it always active without some prompting, but you should be able to allow Flash for individual content by pressing the Activate Adobe Flash:

Or you can enable it for the site, and even choose to remember that you want it active for that site:


Is it possible to set up CUDA 8 on Ubuntu 14.04 using apt-get nvidia driver?

From NVIDIA :

Perform the pre-installation actions.
Install repository meta-data

Note: When using a proxy server with aptitude, ensure that wget is set up to use the same proxy settings before installing the cuda-repo package.

sudo dpkg -i cuda-repo-<distro>_<version>_<architecture>.deb

Update the Apt repository cache

sudo apt-get update

Install CUDA

sudo apt-get install cuda

Perform the post-installation actions.

Read more at: http://docs.nvidia.com/cuda/cuda-installation-guide-linux/index.html#ixzz4ZDVWXs2z


How to list all enabled services from systemctl?

systemctl list-unit-files | grep enabled will list all enabled ones.

If you want which ones are currently running, you need systemctl | grep running.

Use the one you're looking for.  Enabled, doesn't mean it's running.  And running doesn't mean it's enabled.  They are two different things.

Enabled means the system will run the service on the next boot.  So if you enable a service, you still need to manually start it, or reboot and it will start.

Running means it's actually running right now, but if it's not enabled, it won't restart when you reboot.


Upgrading a special software (no matter if other softwares are up to date or outdated)

Yeah. When you try to install a package that is already installed, it upgrades the package if an upgrade is available (and any version dependencies on other packages).

Try this:

sudo apt-get install [PACKAGE(s)]

where [PACKAGE(s)] is/are the package(s) you wish to install.


How to use shortcuts to switch between displays in LXDE?

If you want dual monitor functionality in Lubuntu, you have limited options. The following will show you how to enable and disable dual monitors "on the fly" using ARandR as help. These directions are a bit complicated, but trust me: they are not dangerous. This is a SAFE operation.

First, get ARandR from Synaptic or by opening the terminal and pasting:

sudo apt-get install arandr

You can find your new application under Menu -> Preferences

What you see is a virtual setup of your monitor arrangement. You will almost certainly have different names for your monitor, but here is what mine looks like.

Although you haven't really done anything at this point, save this configuration.

It will automatically create a new hidden folder called .screenlayout in your home directory. I would encourage you to not change the file location to help with later steps. I would also encourage you to use my file names as well. This one should be called single.

Now add your second monitor. It should be hooked up to your computer at this point, of course. I added mine by scrolling through the only other monitors that allowed activation and selected it.

Position the monitors however you like. I prefer side-by-side, but you may also put one above the other. It doesn't matter which one is on the left (or the top). It's all up to you! Here's what I like:

Once you have your desired configuration, save it again. This time, name the file dual.

The last step in this whole process is creating hotkeys to switch monitor on the fly. In the terminal type in the following:

sudo leafpad ~/.config/openbox/lubuntu-rc.xml

Scroll down to a place where you begin to see a lot of words that say <keybind>. You don't need to know what's happening here. Simply find a place after a </keybind>, but before the next <keybind> and paste the following:

<keybind key="W-2">
<action name="Execute">
<command>sh ~/.screenlayout/dual.sh</command>
</action>
</keybind>

<keybind key="W-1">
<action name="Execute">
<command>sh ~/.screenlayout/single.sh</command>
</action>
</keybind>

Your code should look a little like this:

Save. Close. Logout.

If you did everything right, you should be able to press Super+2 to activate dual monitor mode. To go back to one monitor, such as your laptop, press Super+1.

One final note about the lxde panel. When I switched into dual mode, my panel looked a little funny. If you experience this problem, open up your files you created with ARandR in the .screenlayout directory. Add the following lines to the bottom of the files:

lxpanelctl restart

Check out this page I wrote up a few months back.

Good luck.


In simple terms, the swap partition or swap file is used when your installed memory is full and instead of the computer crashing it will place some of its memory in the swap partition.

The swap partition is also used during hibernation. All of the information in memory will be written to the swap partition so the computer does not 'forget' what it was doing when the computer goes into hibernation.

The general rule for swap partition size is equal to the amount of installed memory. In your case 16GB. There must be enough space to write everything in memory during hibernation.

If you do not use hibernation you can decrease (or increase) your swap size. Remember that when the computer uses swap instead of installed memory it will be much slower because reading from a disk take much longer that memory.


Here's how I went about solving the problem

See if networking is enabled
Restart all networking devices
Reconfigure ethernet connection
Restart SMB / CIFS services
Update/Double check nm-settings

sudo lshw -C network
sudo /etc/init.d/networking restart
sudo dhclient eth0
sudo reload smbd

sudo gedit /etc/NetworkManager/nm-system-settings.conf

[main]
plugins=ifupdown,keyfile

[ifupdown]
managed=true


Twofish and Threefish encryption in terminal

Use gpg:

gpg -c --cipher-algo twofish --passphrase=123 myfile

-c: encrypt  with a symmetric cipher using a passphrase.
--cipher-algo : twofish
--passphrase=123: set the passphares to 123
file name of the file

Then check the file type:

$ file myfile.gpg
myfile.gpg: GPG symmetrically encrypted data (TWOFISH cipher)

For stdin you can just pip it to gpg:

echo hi bla bla | gpg -c --cipher-algo twofish --passphrase=123 > file.gpg

or for a variable:

gpg -c --cipher-algo twofish --passphrase=123 > file.gpg <<<"$var"


how to get the available space left deterministically?

To get the available space on / with df, use:

df --output=avail -h / | grep -v ^Avail

How it works

--output=avail tells df to show just the available space.

grep -v ^Avail removes the header line.


I can see why one might want both, especially if you take it around to multiple machines and it's for testing purposes.

For my multiboot sticks I use a program called Multisystem.
It takes care of the grub configuration for you and makes it easy to remove and add various distros.


my left ctrl key not work but right ctrl key is ok.

when I enter settings->device->keyborad ,then reset all shortcut-key. the left ctrl key is ok.


Do I need to worry about defragmentation?

No.  While there may be a little fragmentation in a Linux system using ext4 like Ubuntu, there is no need to worry about it.


Ubuntu Touch on a Nexus 7 (2012/Grouper) but USB/ADB/Fastboot is not working

Your usb port looks OK because of its reading a stick (usb-OTG)
So take another cable; it might be a not fully functional cable, just only for loading your device but not communicating with it.


Can I set up an OpenVPN server in 12.04 w/o OpenVPN Access Server?

Just use the openvpn package and configure it using the regular documentation. While OpenVPN offers commercial support and services, you can just use the free open source version included in Ubuntu that comes as a package (like the other 50000+ pieces of software in Ubuntu).


How to create persistent symbolic links and fix permissions to use the raw print?

In Xubuntu 14.04 you need create a rules file for printers in /etc/udev/rules.d/

$ sudo nano 90-printers.rules

In this file add the follow code:

ACTION=="remove", GOTO="persistent_printer_end"

SUBSYSTEMS=="usb", IMPORT{builtin}="usb_id"
ENV{ID_TYPE}!="printer", GOTO="persistent_printer_end"

ENV{ID_SERIAL}=="?*", SYMLINK+="lp/printers/$env{ID_BUS}-$env{ID_SERIAL}"

LABEL="persistent_printer_end"

Then you can see the new and persistent symbolic links in the following paths:

$ ls -l /dev/lp/printers
lrwxrwxrwx 1 root root 13 jul 21 14:42 usb-Jolimark_USB_Printer_JGHE24ikKU7plwR8x3c6 -> ../../usb/lp2
lrwxrwxrwx 1 root root 13 jul 21 14:42 usb-Jolimark_USB_Printer_MQrvZsOINprsF6dIEor9 -> ../../usb/lp0
lrwxrwxrwx 1 root root 13 jul 21 14:42 usb-Jolimark_USB_Printer_xVc0EQQd3nZzq6ziv8SS -> ../../usb/lp1

These point to the following paths:

$ ls -l /dev/usb/lp*
crw-rw---- 1 root lp 180, 0 jul 21 14:42 /dev/usb/lp0
crw-rw---- 1 root lp 180, 1 jul 21 14:42 /dev/usb/lp1
crw-rw---- 1 root lp 180, 2 jul 21 14:42 /dev/usb/lp2


Hi and welcome to Ask Ubuntu!

You can follow the following steps to get a successful Ubuntu installation using Wubi

1.Setting the installer up

^^That is how your Wubi Installer would look. Set up a username, install location, password, language, size and you're ready for the next step.

2.Downloading Ubuntu

This is fairly easy, and the user (i.e. you), have no role to play in this. Wubi downloads all that is necessary whilst allowing you to carry out your required tasks on Windows.

3.Completing the setup

Now that you have completed the setup, you need to reboot, do note, rebooting is necessary to complete the installation.

4.Final

This is how your screen should look post rebooting. Choose Ubuntu and you can boot into your fresh installation. Hope this helped!

Note: These images do not belong to me I have taken them from this link


How do I reset my Network settings to default (Ubuntu 16)?

Run

ifconfig

and see the name of your network adapter. Mine is: enp0s3

now run this command

sudo nano /etc/network/interfaces

and you should get something inside....delete everything and paste this (but change the network adapter name where enp0s3 is):

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto enp0s3
iface enp0s3 inet dhcp

save the document and reboot...


Look for an error in your Rufus error message that says:
ABORTED: Cannot use an image that is located on the target drive!

The iso you are trying to use resides on the same drive as the one you are trying
to format. You are trying to saw the branch you're sitting on - what you are trying
to do was never going to work in the first place!

Please move your iso to a different drive than your USB, and be mindful that ALL
data on your USB drive will be erased.

If you got this error message do what the error message says and move the .iso file to anywhere in your home directory.


While I respect you intend to only ask one question, how to not load software you don't need, I perceive you to be asking two questions, the other, or primary one, how to make a computer run better with only 2gb of RAM.  I would like very much to answer that question as I suspect I can help.

As you probably know, by default all Ubuntu installations configure some amount of "swap space" on the hard drive, and for most people, that amount is adequate.  For most people 2gb of RAM is adequate as well.  I suspect that your main problem isn't simply that you are running out of RAM, but that you are also running out of swap space.  There are two ways to solve that and one is much easier to accomplish, though the other is probably easier on your RAM situation.

Either manually expand your swap partition.
or
Install this Dynamic Swap Space Manager.

The latter has been my preferred solution for most people, mainly because it permits you to use as much of your drive for swap space as your drive allows, but it doesn't permanently tie up any of your drive as a dedicated swap partition.

There is one more thing you might do, but only if it applies to you:
IF you are running the 64 bit version of Ubuntu 14.04, please downgrade to the 32bit version.  It is my impression that the 64 bit version uses or wastes memory at about a 2:1 ratio as compared to the 32 bit version.


How to Request a Driver Be Included in 16.10 and Up rtl8812AU

There is rtl8812au-dkms, which seems to be the driver you want. It's available for 16.04, 16.10 and 17.04.


You can add

* * * * * date > /tmp/current_time.txt

and see what time cron is running with. Cron will use local time so it should (by default) show UTC.
See /etc/default/cron if you want to change it. It will show TZ=UTC (by default).


Installing YUM in Ubuntu 20.04 to run CentOS LXC Containers

Well, definitely it is not an optimal solution, but it is the only one I found.
As I'm using Dockers quite often, I have docker installed and I've created a new /usr/bin/yum file (executable) with this code:
#!/bin/bash

docker run --rm -v /var/cache:/var/cache roboxes/centos8 bin/yum $*

So when yum is executed, my own docker version of "yum" runs. It is not a nice solution, but at least it does the job.
I've previously run, though this is not mandatory.
docker pull roboxes/centos8

No RPM package is needed either.
No CentOS 8 is supported in this LXC version (because of the lxc-centos template). It is not optimal, but it worked.


error: no such partition Entering rescue mode... grub rescue>

If you have ubuntu live cd, boot from cd and click try ubuntu
Then find terminal window
Type sudo apt-get install lilo and then sudo lilo -M /dev/sda mbr (you should have      internet connection to perform this) then restart
If you do not have internet follow this on latest ubuntu live cd's  sudo dd if=/usr/lib/syslinux/mbr.bin of=/dev/sda


ccrypt is a pretty decent way of quickly scrambling a file (or files).

It's in the repositories, so just install with:

sudo apt-get install ccrypt

It comes with a handy variation of cat, called ccat. If you encrypt a text file with ccrypt you can use ccat to quickly display it in the terminal.

ccrypt isn't just for text files though. You can use it on any files.


Graphical glitches using Ubuntu 18.04 on Dell XPS 13 2019 laptop

This is not screen tearing, these are quite severe graphical glitches, which you may find occur more frequently when on battery power. This is probably related to a more recent type of Intel graphics in that laptop, and the kernel mode drivers still need to catchup.
See whether adding i915.enable_psr=0 to your kernel boot line helps. For how to add that particular command line option, I can refer to another post on AskUbuntu. This disables a power saving feature and so will cause your system to use a bit more battery.
Update: I still need the setting in Ubuntu 20.04 on kernel 5.4.0-40-generic
Update: I may still need it on 20.10: after resuming from a blank screen, glitches occurred.


Installing an Asus usb-n14 adapter which comes with an install dvd including files for Linux

You can install the driver this way

sudo add-apt-repository ppa:hanipouspilot/rtlwifi
sudo apt-get update
sudo apt-get install rtl8192cu-dkms linux-firmware

and reboot.

And you do not need any disk ;-)


How can I set up GPT and EFI for my new raw drive?

There are two separate (but related) technological dichotomies that you seem to be conflating, at least a bit:

BIOS vs. EFI/UEFI -- This is the type of firmware in the computer; it's software that's built in to chip(s) on the motherboard. Since the 1980s, PCs have used Basic Input/Output System (BIOS) firmware, but the Extensible Firmware Interface (EFI) was developed in the 1990s, lurked for over a decade as an obscure option on Itanium systems, was adopted by Apple for its Intel-based Macs, and has most recently been used as a BIOS replacement on the vast majority of PCs sold since mid-2011 or thereabouts. (EFI 2.x is known as the Unified EFI, or UEFI.) Although some PCs used EFI prior to 2011, chances are your 2009 laptop is not one of them, so you really can't use EFI on it. (You might be able to get a "software EFI" such as DUET or Clover to work on your system, but this is more trouble than it's worth for most people.)
MBR vs. GPT -- PCs have historically used the Master Boot Record (MBR) partitioning system. This is just a set of standards for how to arrange data on the disk so that the OS can find the partitions. EFI includes a new partitioning system known as the GUID Partition Table (GPT), which eliminates many MBR kludges and limitations. Although GPT is defined as part of the EFI specification, it may be used even on older BIOS-based computers. GPTs biggest advantages are with disks over 2TiB in size, which MBR can't handle. On smaller disks, GPT has several minor advantages, but nothing compelling enough to make switching to it a necessity for most users. Note that some OSes, including Windows, cannot boot from GPT disks except in EFI mode -- and of course most older OSes, such as DOS and most versions of Windows prior to Vista SP1, can't boot in EFI mode or use GPT even for data disks.

The term "EFI partition" is somewhat ambiguous because that is not, AFAIK, an official moniker. In the paragraph you quoted, it seems to be referring to an EFI System Partition (ESP), which is a partition on which EFI boot loaders and similar EFI tools are stored. An ESP is 100% useless on a BIOS-based computer, so if your laptop is BIOS-based, as I suspect, there's no point in creating an ESP even if you use GPT. BIOS-based computers that have GPT disks and boot with GRUB instead use a BIOS Boot Partition, which is a small (typically 1MiB) partition that holds part of GRUB. The BIOS Boot Partition is identified in different ways depending on the partitioning tool you use. In parted, GParted, and other libparted-based tools, it has a bios_grub flag set. In gdisk and its siblings, it's identified by a type code of EF02.

If you pre-partition your disk and want to use GPT, create a BIOS Boot Partition and whatever other partitions you'd normally use. If you anticipate eventually moving the disk to a newer EFI-based computer, you might create an ESP, too, but that's almost certainly just a (small) waste of disk space at this time. (ESPs are typically 100-600MiB in size.)


Windows Media Center DVR TV Tuner and TV Guide Replacement

You can try either mythTV, or XBMC (Kodi)

MythTV is a free, open source media center and digital video recorder (DVR) distributed under the terms of the GNU GPL. With its plugin architecture, MythTV can be transformed into a home media center suite, capable of managing your personal photo, video, and music collections, as well as keep you up to date with the weather, a ZoneMinder home security system, and much, much more.mythTV

sudo apt-get update
sudo apt-get install mythtv
sudo mythtv-setup

Rebbot you system, and re-run the setup again

mythtv-setup

If you get a message saying that Myth could not connect to the database, check that the password on the screen matches the one in /etc/mythtv/config.xml

sudo cat /etc/mythtv/config.xml

XBMC(Kodi)XBMC started as “Xbox Media Center.” It’s designed to play back video from local files, network shares, or online streaming services. If you use your media center PC for playing back downloaded files or streaming Netflix, Hulu, YouTube, and other online sources, you’ll want XBMC.Kodi

sudo apt-get install software-properties-common
sudo add-apt-repository ppa:team-xbmc/ppa
sudo apt-get update
sudo apt-get install kodi


"eth0 not configured" but it was working earlier

First of all, it appears that, from your comments, that you have removed the loopback stanza from /etc/network/interfaces. It mustn’t be removed. Please amend the file to add back:

auto lo
iface lo inet loopback

Next, ifup and ifdown are specifically reserved to manage interfaces which are declared and configured in /etc/network/interfaces. You have none. That is why you get the complaints when you issue the ifup command.

ifup eth0 is, roughly, shorthand for, “Bring up the interface found in /etc/network/interfaces which is declared as eth0.”

If you have removed eth0 and wlan0 from /etc/network/interfaces, then Network Manager should once again manage the interfaces. Restart NM:

sudo service network-manager restart


Ubuntu 16.04 no longer booting on Lenovo Y70 Touch Error "Verification failed: (0x1A) Security Violation

Turn off secure boot in the BIOS/UEFI.
Also try to save settings or press F10 and choose yes at the save dialog.
Edit: On a second thought this could be solved by signing/trusting the bootloader, kernel and kernel modules for UEFI Secure Boot too.
But to do this one has to find a live media which will still boot the machine. Then create a chroot environment, do all the complex work needed to prepare a secure boot. Then save the results to the internal file system.
Then reboot and see what happens. If issues arise (yes there may be problems even if you have related experience) you have to start it over and check what went wrong.
This may take days or weeks to solve it this way. If you wish to learn by this it may be worth doing, otherwise it's just a waste of time.
I guess the difficulty is way beyond intermediate level sysadmin skills.
Nevertheless, I've found some nice Ubuntu based documentation how to do the secure boot part, in case you chose to try.
UEFI Secure Boot - Ubuntu
Key generation
Secure boot signing
DKMS part for kernel modules


Can't add repository due to 'missing' fingerprint

Run this:

$ sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 8D0DC64F
$ sudo apt-get update

This solve your problem.


Ubuntu VM does not detect external disk attached to host.

First make sure that you have Guest Additions are installed.  Then, make sure that USB is enabled, and that the USB device is connected to the VM.  See images below.


In general the structure of apt repositories does not allow for multiple versions of a package to be present.  A list of all package mirrors for Ubuntu can be found at Launchpad.  Since Ubuntu inherits from Debian the apt repository system, the description there of the repository format helps explain how it is set up.  An example of where a directory on the archive may contain multiple versions but for different releases would be in the pool for xubuntu-docs where there are versions for each separate release but not multiple versions per release.


How can I increase the scroll speed of my 'Logitech K400' mouse?

I can tell you it for Firefox:

In the address bar, navigate to about:config
accept the warning about risks of powerful settings
in the additional search bar that appears, search for:

mousewheel.default.delta_multiplier_y

The default value is 100. Just to provide an example, I have it at 225.

Update:
I have found this another question on this site: How can I adjust the mouse scroll speed?
I can't point to any Holy Grail solution in it; a lot of different approaches are offered, but a lot of them are no silver bullet.


Replace source word with containing /(forward slash) to destination word in VI editor command window

In the example you gave, with a file containing

/root/repo/my-gerrit/myData.cpp

This can be changed to

/repo/my-gerrit/myData.cpp

with the command :%s/\root//gc.

You attempted %s\/root\/\repo\/repo/gc, which lacks the normal forward slashes. To replace /root/repo/ with /repo/, the command would be %s/\/root\/repo\//\/repo\//gc

Note that forward slashes that you want to replace are escaped with \. Forward slashes that is part of the command is not escaped.


sha256sum/md5sum gives different results for big files (Ext4/Full disk Encryption)

You're looking at a hardware issue here. Memory in consumer hardware lack integrity checks (ECC), so errors in the memory go mostly undetected at system level. As you noted you were seeing crashes too, and that is to be expected if memory is faulty.

By running a memtest on your system you can verify this. Memtest with Ubuntu 12.04 live CD

You'll now also have to verify all backups as I/O goes through memory it's likely that backups made with this faulty RAM are corrupted too. Note that is can be slightly corrupted and hard to spot.


As with Bor's answer, upgrading to the Remmina 1.2 "next" version solved my issue with folder shares not showing up when RDP-ing from Ubuntu 15.10 to Windows Server 2012 R2.

As in the instructions at https://github.com/FreeRDP/Remmina/wiki, simply run:

sudo apt-add-repository ppa:remmina-ppa-team/remmina-next
sudo apt-get update
sudo apt-get install remmina remmina-plugin-rdp libfreerdp-plugins-standard

or in one line by concatenating the commands together with &&.

Then start Remmina =)

remmina


How to Provide Unity Desktop Integration Features to Site on Chromium

You must install the extension and make Chromium default browser:

sudo apt-get install unity-chromium-extension


How to list the packages to be installed by installing a specific package?

The basic command to show dependencies is

apt-cache depends <package>

which will show you the dependencies (there is even a rdepends option to show the reversed dependencies).

You can add this to the @ByteCommander's suggestion to use simulate install to see which packages will be installed in your system:

apt-get install -s ubuntu-desktop

(no need to use sudo in simulated mode!)

But to really answer the question, no, it is not possible sometime to go completely back. A classical example is ubuntu-gnome-desktop (Gnome shell) and ubuntu-desktop (Unity). Their dependencies partly overlap --- for example:

[romano:~] % apt-cache depends ubuntu-desktop | grep seah
  Depends: seahorse
[romano:~] % apt-cache depends ubuntu-gnome-desktop | grep seah
  Depends: seahorse

...and the overlapping packages may have different configuration defaults.

You can approximate the thing you want by purging all the packages and reinstalling them --- but it can be really dangerous, because the intermediate step can be a non-functional  system.

Even outside of the packages, sometime the DEs make changes in your home directory that can affect other DEs (and files in your home are not restored even using purge and reinstall). So if you want to check another DE, do that with a fresh new user.

My personal experience is that the "insulation" of the various desktop environments is not perfect at all; Unity and Gnome shell are the worst offenders (probably because they share a lot), with other it can be better --- I do not know.


How do I create a desktop entry to launch a Python script?

May I offer a few notes and improvements over the accepted answer?

Manually installing software to /usr/share is strongly discouraged!!! That tree should be reserved for software installed by your package manager (Ubuntu Software Center, apt, etc). There is usr/local/share for that. Or, if you don't want to use sudo, you may install for your user only at ~/.local/share. See https://askubuntu.com/a/135679/11015 for more information about software install directories.
If you want to execute a .desktop file by double-clicking on it, in Nautilus or your Desktop, just make the .desktop file executable! Note that this is not required if you copy it to /usr/share/applications and launch it via Dash/Menu. Or, better: copy to ~/.local/share/applications or at least /usr/local/share/applications, as suggested above.
Icon=/usr/share/MyApp/MyApp.py makes no sense: a .py file is not a valid image, so it cannot be used as an icon. If you want to use the default python icon, use /usr/share/pixmaps/python.xpm
The main difference between your .desktop file and the accepted answer is the Path=/usr/share/MyApp/ statement. If that made your app work, it means your software requires the current directory to be the application directory. And that is a bad thing: your software should be able to run fine and find its data files regardless of current directory. (hint: use python's __file__)
If your application is a GUI (ie, it has a window), then add StartupNotify=true. It will help the launcher identify its window when it is running.


Performance overhead of LXD running as a SNAP

About twenty years ago, it was common to install several network services onto the same server. For example, if you had fifty websites, they were all onto the same server, using virtual hosts (Apache2 terminology). Not much separation between each website, apart from the Unix permissions.
You can still do such a thing, and in terms of performance/density it would be unrivaled. But you tend not to do this anymore, because it becomes a management nightmare, and also a security risk. How can you easily remove the five websites of a specific customer? How do you separate the five websites of a customer from those of other customers?

The message is that, with even better computers it is OK to trade some of the density/performance for other features.

Hardware virtualization takes away quite a lot of resources off the CPU. But still people use VMs. This is where system containers come in, where you get some of the benefits of a virtual machine, but you achieve isolation thanks to the Linux kernel security features. You would use system containers in a VM to further separate your network services.

Snap packages have many advantages that are discussed elsewhere. The snapd service does only the management of snap packages, deciding when to update a particular package. It takes some memory, which you can measure. You can configure when to update packages, whether to delay an update (up to two months), which channel to track (like 4.0/stable, with minimal updates for the next five years).


Inkscape gives errors when I switch to WebStorm

Here's what worked for me ..

sudo apt-get update

- Just in case

then installed this :

sudo apt-get install python-dev python-software-properties

And voilá .. until now .. no more issues .. hope it helps more peeps ..


Have you tried enter this in the terminal:

 rfkill unblock hard

and that it is, and it might work fine this way.


Can I open Synaptic Package Manager in a Ubuntu Live CD session?

Synaptic package manager isn't  included in the Live CD. but you can install it. But, I think, you should better use the terminal. Open it with Ctrl-Alt-T shortcut and run this command to install testdisk

sudo apt-get update
sudo apt-get install testdisk

or using the install button below:

You can then use testdisk. If you want to install synaptic, use this command instead

sudo apt-get install synaptic

After installation, use sudo testdisk command in the terminal to start using it.


Difficulty Removing Installation Files -- I think

To fix:
W:Skipping acquire of configured file 'main/binary-i386/Packages'
as repository 'http://dl.google.com/linux/earth/deb stable InRelease'
doesn't support architecture 'i386'

Edit two files:
sudo -H gedit /etc/apt/sources.list.d/google-earth-pro.list
And change:
deb http://dl.google.com/linux/earth/deb/ stable main

To:
deb [arch=amd64] http://dl.google.com/linux/earth/deb/ stable main

sudo -H gedit /etc/cron.daily/google-earth-pro
And change:
REPOCONFIG="deb http://dl.google.com/linux/earth/deb/ stable main"

To:
REPOCONFIG="deb [arch=amd64] http://dl.google.com/linux/earth/deb/ stable main"

To fix:
E:Repository 'http://ddebs.ubuntu.com bionic-updates Release' changed its
'Suite' value from 'bionic' to 'bionic-updates',
E:Repository 'http://ddebs.ubuntu.com bionic-updates Release' changed its 'Codename'
value from 'bionic' to 'bionic-updates'

cd /etc/apt # change directory
grep -i ddebs.ubuntu.com sources.list # search this .list file
grep -i ddebs.ubuntu.com sources.list.d/*.list # search other .list files
sudo -H gedit found_path/found_filename.list # edit the found .list file
Find the line that contains ddebs.ubuntu.com and change bionic to bionic-updates


How to correctly install and use QEMU-KVM on Ubuntu 14.04?

You installed everything correctly. QEMU did not disappear. The documentation is simply not up to date. You should use the qemu module name appropriate for your architecture. For example, instead of qemu <image-name>, run:

qemu-system-x86_64 <image-name>


Check BIOS settings. There could be option to use integrated graphics, instead of graphic card, of-course only if you have on board graphics on motherboard. There could be graphical way or from within  Ubuntu, but best thing would be to use BIOS settings.


I have found that wireless is always slower than the wire for one thing. Another factor is other computers using the wireless connection at the same time. Wireless routers have trouble supporting more than a few concurrent connections at the same time. The first thing I would do is log into the router and look at the DHCP clients to see who is connected. You may unwittingly be giving free internet to a neighbor.


You can check two things:

Add logging:

0  6  * * * /usr/sbin/apachectl -k graceful >> /tmp/a.log 2>&1
0  3  * * * /usr/bin/letsencrypt renew >> /tmp/b.log 2>&1

Check logs:

cat /tmp/a.log && cat /tmp/b.log
tail -f /var/log/syslog | grep -i cron


What do you think where 'localhost' aka 127.0.0.1 goes? Thats your network-card and if there is a printer connected it will have annother ip-address. So printing on 127.0.0.1 will not work.
Try install a new printer in your printing dialog, if it will be identified thats ok, if not post some more information about your network.


How to extract one file from a specific directory of a zip file

Don't use a leading slash, and just give the path to the file as the second argument:
unzip zipfile.zip -JWQYBCVAQA=/test.txt

You can also use wildcards:
unzip zipfile.zip '*/test.txt'

For files/directories whose names start with -d or -x (which are the options allowed after the zip filename), to escape them you can prefix with \\ (\ for unzip itself, and the extra escape for the shell) or '\'.


I cannot use non-letters keys (czech layout) in any application

If you use czech layout, you can type for example [ as follow:

The things goes something like follows. Let's take for example this key:

To type ú - press ú.

To type / - press Shift+ú.

To type [ - press AltGr+ú.

To type ÷ - press AltGr+Shift+ú.


Can't read and change original pg_hba.conf in PostgreSQL 12

Okay! I have got the problem and it was a little error in my text path to 'bg_hba.conf' ->  'pg_hba.conf' /etc/postgresql/12/main/bg_hba.conf' this change on this - > /etc/postgresql/12/main/pg_hba.conf'


how to check if the files exist on remote server or not

Set the variables with single quotes to avoid expansion of the wild-card in your local computer,
FILE='20200819-001-*'

The command find can manage wild-cards, so I suggest the following command instead of the simple test,
find "$DIR" -maxdepth 1 -name "$FILE"

or if you want to check in subdirectories without limiting the depth of the search,
find "$DIR" -name "$FILE"

So in your shellscript you check if the find command line produces some output or not,
if [[ $(ssh "$HOST" find "$DIR" -maxdepth 1 -name "$FILE" ) != "" ]]


Not using a proxy but still getting "Something wicked happened resolving.." error

Go to Settings / Network.

On the left side panel, click "Network proxy".

In the "Method" box, choose "None". Click on "Apply system wide".

Open a Terminal window and

sudo apt-get update

It should work now.


So, if all 1000 ports are closed how the pc connects to the internet ( because it is connected )? And if port xxx on the localhost is LISTEN-ing why nmap can't detect it?

When you connect to some remote site, the local program opens a socket against the server, identified by the local port, remote port and the remote IP. It will not receive packets not matching this tuple.

The local port is typically selected from the ephemeral ports. Those are not scanned by nmap by default, and would not show up either, as nmap doesn't match the tuple for the socket.

What nmap looks for is open sockets, accepting connections. According to nmap you have one, but you have masked it, so we don't know if nmap checks that port. There's 65535 ports, but by default nmap only scans about 1000 of them.

  What is the difference between the ports of the localhost and the ports of the ... eth0?

Things listening on 127.0.0.1 will only receive packets on the loopback interface. Things listening on 0.0.0.0 or a specific device will receive packets either from all (0.0.0.0) or on that specific device.

  Are there 65535 ports for the localhost and other 65535 ports for the eth0 network-interface?

Yes, and no. A connection consists of the tuple local port, remote port, remote IP and possibly local IP. You can have different services listening on the same port on two different IP's.


Updating/patching an airgapped Ubuntu server

use

apt-zip - Use apt with removable media

or

apt-offline - Offline APT Package manager

here are a couple of usage guides for apt-offline:

https://debian-administration.org/article/648/Offline_Package_Management_for_APT
https://blog.sleeplessbeastie.eu/2014/01/30/how-to-manage-packages-on-an-off-line-debian-system/


How I do set Xcowsay on login without the cow disappearing?

The main problem that when we logon, the devices are not mounted except for the root device and home directory. Even sometimes, home directory fails to start. So application run normally which belongs to the path file system/user/bin/ directory as an executable otherwise may cause problems even if it belongs to some other paths. Well try to check if you have checked it in the startup application window.
Also check if your file is listed here Check ~/.config/autostart. Try to add the application there and then it will run properly I suppose.


juju deployment error on manually provisioned machine

Judging by the juju status output, you've bootstrapped a manual environment (using juju bootstrap, which is different from manual provisioning, done using juju add-machine ssh:[user@]host).

Manual environments are special - they consist only of a single machine and it cannot start or stop additional machines automatically, including on juju deploy. To add another machine, use juju add-machine ssh:[user@]host first, then juju deploy juju-gui --to #, where # is the juju machine id of the machine you've just added (run juju status to see it). You can also use juju deploy juju-gui --to 0 to deploy Juju GUI on the bootstrap machine.

juju add-machine ssh:[user@]host can be used in any bootstrapped environment to manually provision an external machine and add it to the environment. But with a manually bootstrapped environment, that's the only way to add machines, and you have to specify placement for services and units when deploying, with --to <machine-id> explicitly.

I hope that clears up any confusion. We definitely need better documentation on that I suppose.


Should I install always and all new updates in "update manager"?

Notice that not all that you download is added on-top of your current system, most of it just replaces current installed software, thus it doesn't take up much more space than before.

Keeping your software up to date is important from a security point of view, and not only Ubuntu Security updates, but also third party software installed on your computer to close security gaps in those applications.


Sessions are automatically logged (up to 10,000 lines per windows).

You can "scrollback" any time by pressing Alt-PgUp and Alt-PgDn.  Note that you're in "vi mode", so you can also search for strings using / and ?.  Press Enter to exit.

Now, you can also save that window to a file by pressing Shift-F7, which will write the buffer to $BYOBU_RUN_DIR/printscreen.

Full disclosure: I am the author and maintainer of Byobu.


You have the option to Dual Boot between Windows 7 and Ubuntu. Typically this works well and you will be presented with an option to boot Ubuntu or Windows every time you boot. The important thing to watch for if you want to keep Windows is when installing, choosing the option to install Ubuntu side-by-side. Here is more information on Dual Booting Windows and Ubuntu: https://help.ubuntu.com/community/WindowsDualBoot


How can I set up local wildcard (127.0.0.1) domain resolution on 18.04..20.04?

Here are the steps for ubuntu since 18.04. It's a little bit long since systemd-resolved does not play very well with NetworkManager when configured with dnsmasq.
Yet I still recommend starting dnsmasq from NetworkManager, because network connectivity changes (WIFI, wired, ...) will be handled transparently.
Enable dnsmasq in NetworkManager
Edit the file /etc/NetworkManager/NetworkManager.conf, and add the line dns=dnsmasq to the [main] section, it will look like this :
[main]
plugins=ifupdown,keyfile
dns=dnsmasq

[ifupdown]
managed=false

[device]
wifi.scan-rand-mac-address=no

Let NetworkManager manage /etc/resolv.conf
sudo rm /etc/resolv.conf ; sudo ln -s /var/run/NetworkManager/resolv.conf /etc/resolv.conf

Configure example.com
echo 'address=/.example.com/127.0.0.1' | sudo tee /etc/NetworkManager/dnsmasq.d/example.com-wildcard.conf

Reload NetworkManager and testing
NetworkManager should be reloaded for the changes to take effect.
sudo systemctl reload NetworkManager

Then we can verify that we can reach some usual site :
dig askubuntu.com +short
151.101.129.69
151.101.65.69
151.101.1.69
151.101.193.69

And lastly verify that the example.com and subdomains are resolved as 127.0.0.1:
dig example.com askubuntu.example.com a.b.c.d.example.com +short
127.0.0.1
127.0.0.1
127.0.0.1


Boot your machine from an Ubuntu live CD/DVD or live USB stick (like you would use to install Ubuntu). Select Try Ubuntu (not Install Ubuntu). Run the GParted Partition Editor (you can search for gparted in the dash).

Shrink down your 581 GB partition (/dev/sda6) to make room to the left. Shrink it by however much space you want to add to the /boot partition--in this case, by about 408 MB. (You may have to shrink it, then move it to the right.)

Then expand the /dev/sda1 partition to take up the newly available unpartitioned space.

Apply your changes by clicking the green check mark.

Quit GParted and reboot back into the Ubuntu system installed on your hard disk. Now your /boot partition is about 500 MB in size, and your / partition is shrunk by about 408 MB to make room for it.

Finally, please note that you should not attempt to change the sizes of partitions on the system drive from the installed Ubuntu system. At best GParted will refuse to operate and at worst you can severely mess up your Ubuntu system and even have data loss. This is why you need to boot from a live CD to perform these operations. That is relatively safe, but whenever you dynamically resize partitions there's a small risk of data loss (either if the operation fails or if you make a mistake), so you should make sure all your backups of your documents and other important (i.e., irreplaceable, or tough to replace) files in your Ubuntu system are current before you perform the above procedure.


Open your terminal and then mention as:

export QTDIR=/usr/share/qt4

And then do make.


how to create a shortcut for libre office calc file in Lubuntu 18.04

I got the answer from here. The trick is to create a link by dragging the document to the Desktop while holding down CTRL+SHIFT


Lubuntu doesn't see Ethernet and Wireless connection on Dell 1300 Inspiron

For a 64-bit system:

Download these files to your home folder:

http://mirrors.kernel.org/ubuntu/pool/main/b/b43-fwcutter/b43-fwcutter_018-2_amd64.deb
http://www.lwfinger.com/b43-firmware/broadcom-wl-5.100.138.tar.bz2

Then run in terminal:

sudo dpkg -i b43-fwcutter_018-2_amd64.deb
tar xfvj broadcom-wl-5.100.138.tar.bz2
sudo b43-fwcutter -w /lib/firmware broadcom-wl-5.100.138/linux/wl_apsta.o

For 32-bit:

http://mirrors.kernel.org/ubuntu/pool/main/b/b43-fwcutter/b43-fwcutter_018-2_i386.deb
http://www.lwfinger.com/b43-firmware/broadcom-wl-5.100.138.tar.bz2

sudo dpkg -i b43-fwcutter_018-2_i386.deb
tar xfvj broadcom-wl-5.100.138.tar.bz2
sudo b43-fwcutter -w /lib/firmware broadcom-wl-5.100.138/linux/wl_apsta.o

You can download the files using another computer.

The Ethernet should be fixed by

sudo apt-get purge bcmwl-kernel-source


How can I have 2 rows and 3 columns of desktops/workpaces in Lubuntu?

With LXDE the fine adjustment of desktop appearance is reduced as compared to other non-light weight desktops. Therefore by using Desktop Pager for workplace management you will only be able to set the number of desktops but not their appearance in rows and columns.

Still, if you desperately need this there is a way to disyplay 2 rows of desktop icons in the panel by increasing the panel height from the Panel Settings (right click on the panel to open) to a value of lager than 40 pixels:

To toggle between workspaces when moving the mouse to the screen borders you may be interested in brightside  that is called with the command brightside from a terminal or by putting in autostart.

brightside-properties

sets the application's options.


I started trying to install MariaDB MySQL. Now I have a mess, looks like I can't install packages now

Don't reinstall. If you don't have any valuable data in your databases, you can try this :

sudo dpkg --remove --force-remove-reinstreq mariadb-server


What command can I use to change the output location of MPlayer?

It should work this way:

mplayer -vo png:outdir=/var/www/html -frames 1 tv://

but it does not work for me. I do not know why.

But this works:

mplayer -vo jpeg:outdir=/var/www/html -frames 1 tv://


Where can I suggest spell check improvements?

Both Chromium and IE do not not underline the word curation on my system. From the context menu I assume Chromium uses Google translate.

Firefox does underline it. Select the word and right click. You will see an option 'add to dictionary'.  After adding it the line is no longer marked. If they did their job well this word is not sent to their servers ;)

LibreOffice has its own dictionary. Highlight the word and press f7. You can then add it to your dictionary.

All of these are local and there is not a central database to report this.

After some more digging!

They all seem to use Hunspell. http://hunspell.sourceforge.net/

  Hunspell is the spell checker of LibreOffice, OpenOffice.org, Mozilla Firefox 3 & Thunderbird, Google Chrome, and it is also used by proprietary software packages, like Mac OS X, InDesign, memoQ, Opera and SDL Trados.

So the place to report them is here: http://sourceforge.net/tracker/?group_id=143754&atid=756395

Chromium also uses Hunspell.

  You can also help by reviewing word lists of words we've identified as popular but not in the dictionary. Please contact brettw AT chromium.org if you are interested.

So this will/should work for all the software mentioned in this answer :)


How to Properly Transfer by cmd. line PGP Keys in a New Computer [e.g. Launchpad OpenPGP Key]

After running through my notes when I originally created the PGP Key some years ago I found this answer on Ask Ubuntu:

$ gpg --keyserver keyserver.ubuntu.com --recv-keys 245FD525
gpg: requesting key 245FD525 from hkp server keyserver.ubuntu.com
gpg: key 245FD525: public key "my_name <my_e-mail>" imported
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
$ gpg --no-default-keyring -a --export 245FD525 | gpg --no-default-keyring --keyring ~/.gnupg/trustedkeys.gpg --import -
gpg: keyring `/home/ubuntu-xenial/[user]/.gnupg/trustedkeys.gpg' created
gpg: key 245FD525: public key "my_name <my_e-mail>" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
$ gpg --list-keys [user]
pub   2048R/245FD525 2016-12-16
uid                  my_name <my_e-mail>
sub   2048R/4D0AABD3 2016-12-16
$

Now I can use my Launchpad PGP Key on the other computer.


I think Hive expect to find Derby database in current working directory. Hive will create the database, because create=true in javax.jdo.option.ConnectionURL property, but will not initialize schema in the database.

My configuration:

Ubuntu 18.04.1 LTS
Hadoop 3.1.1
Hive 3.1.0
Apache Derby from Ubuntu repositories (Version: 10.14.1.0-1ubuntu1 currently)

sudo apt install derby-tools libderby-java libderbyclient-java

According Hive Documentation we need to run ShemaTool explicity.

I decide to keep my Derby database into HIVE_HOME (/opt/hive-3.1.0-bin in my case) directory. You can setup Derby database location in hive-site.xml:

<property>
    <name>javax.jdo.option.ConnectionURL</name>
    <value>jdbc:derby:/opt/hive-3.1.0-bin/metastore_db;databaseName=metastore_db;create=true</value>
</property>

Ensure that there is no Derby database yet:

$ ls $HIVE_HOME/meta*
ls: cannot access '/opt/hive-3.1.0-bin/meta*': No such file or directory

Start Hive:

$ pwd
/home/hadoop
$ hive
hive> show tables;
FAILED: HiveException java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
hive> exit;

Now we got Derby database, but it's not functional:

$ ls -d $HIVE_HOME/meta*
/opt/hive-3.1.0-bin/metastore_db

So, we need to create metada schema:

$ rm -rf $HIVE_HOME/metastore_db
$ cd $HIVE_HOME
$ schematool -initSchema -dbType derby
...
Initialization script completed
schemaTool completed

Now Hive is working as expected:

$ cd
$ hive
hive> show tables;
OK
Time taken: 0.803 seconds


Wifi keeps dropping out - Ubuntu 20.04 and Broadcom wireless adaptor

I was in a similar situation since two weeks and I found a solution yesterday (11th May) which is working so far (dual boot Ubuntu 20.04 / Windows, wireless card Broadcom 4325).

Surprisingly, my issue was not due to wireless driver or power management (tried many things in previous days, no improvement) but related to the ARP entry of my computer expiring on my local router (ARP stands for Address Resolution Protocol, it makes translation beetween IP addresses and MAC addresses).

To make it short (investigation details at the end of this answer) :

The ARP entries of my router have a timeout of 20 minutes,
For my computer it was decreasing up to expiration (which made me lose connection every 20 minutes),
And the same for other devices but for them it was automatically refreshed before expiring. I made network captures to find out what these devices were doing differently and found that their timeout is refreshed when they send an ARP request.

=> A solution appeared, I had to tell my computer to do the same ! (send ARP request)

Implementation of the solution

To send an ARP request, I used arping that you can install from its package :

sudo apt install arping

When you launch it, it says that it must run as root or with the cap_net_raw capability.
Since I didn't wanted to launch it as root, I added the capability :

sudo setcap "cap_net_raw+ep" /usr/sbin/arping

I used the following command to send one ARP Request to my router (replace the IP address with the one relevant for you) :

arping -c 1 192.168.1.1

Then I wanted this command to run every 15 minutes to refresh the ARP entry regularly.
This is done by editing the file /etc/crontab :

sudo vi /etc/crontab

And adding this line at then end of the file :

*/15 * * * * <username> arping -c 1 192.168.1.1

That will make the ARP request sent every 15 minutes.

Detailed investigation process

Here are more details on how I discovered the issue :

Developped a widget telling me with timestamps when the connection is lost, and when it comes back.
Running a tcpdump capture until a disconnection/reconnection happens (purpose of the widget).
In the capture, found ARP messages around the issue time.
Looked into the ARP table of my pfSense router and saw that the timeout entry for my PC was always decreasing until expiration ; for other devices connected it decreased also but at some point it was resetting to default value (1200s in my case) before expiration.
Waited until expiration to confirm I observe the disconnection symptom on my computer (yes).
Made tcpdump captures on the router to see how others devices were successfully resetting their timeout : by sending ARP requests before it expires.
Installed arping as explained above and sent a test ARP request to the router : it resetted my expiration timeout to 1200s, victory ! \o/

Finally, I don't know why I never faced this issue when using Windows.
When checking the ARP table I see the entry becoms expired as well but then immediately get resetted to 20 minutes and I cannot see a network disconnection.

You may also wonder how to check the ARP table.
If you are using a pfSense router, it can be found in the submenu "Diagnostics > Table ARP" (to be translated in English, my menus are in French).
With another device, you will have to check its documentation.

But at the end, event if you can't check the ARP table you can still try to insert the line in /etc/crontab and run it for a couple of hours/days. If your problem doesn't reappear then it was the issue :-)

Hope this helps !


How do I change extension of multiple files recursively from the command line?

A portable way (which will work on any POSIX compliant system):

find /the/path -depth -name "*.abc" -exec sh -c 'mv "$1" "${1%.abc}.edefg"' _ {} \;

In bash4, you can use globstar to get recursive globs (**):

shopt -s globstar
for file in /the/path/**/*.abc; do
  mv "$file" "${file%.abc}.edefg"
done

The (perl) rename command in Ubuntu can rename files using perl regular expression syntax, which you can combine with globstar or find:

# Using globstar
shopt -s globstar
files=(/the/path/**/*.abc)

# Best to process the files in chunks to avoid exceeding the maximum argument
# length. 100 at a time is probably good enough.
# See http://mywiki.wooledge.org/BashFAQ/095
for ((i = 0; i < ${#files[@]}; i += 100)); do
  rename 's/\.abc$/.edefg/' "${files[@]:i:100}"
done

# Using find:
find /the/path -depth -name "*.abc" -exec rename 's/\.abc$/.edefg/' {} +

Also see http://mywiki.wooledge.org/BashFAQ/030


The Thunderbird extensions you have installed are in

~/.thunderbird/123abc.default/extensions/

usually, with 123abc being some random characters.

In that directory, there are extensions either as *.xpi files, or as subdirectories.
In both cases, they can have a clear name, or a cryptic number in {}.

I propose to list them in order of last change, and try to identify the ones that match the interesting time range:

$ cd ~/.thunderbird/*.default/extensions/
$ ls -ltr

The direcories contain a file install.rdf that should explain what it contains.

Maybe what you see is easy to identify, if not ask in a comment here.

From comments: So you see the directory {9533f794-00b4-4354-aa15-c2bbda6989f8}.

From asking google for 9533f794-00b4-4354-aa15-c2bbda6989f8, it seems to be the addon firetray. With the relation to "tray", it is probably be related to the notifications.

Hard to tell whether it's the useful part of what you installed, or not.
Experiment if it's not clear to you too: Take a look at it's settings, disable or remove it.

If you need to find out which software packages you installed recently, independent of Thunderbird, like with apt-get install foo:
There are log files of the package system to help.

The files are in /var/log/apt/, named history.... The newest are history.log and history.log.1.gz

The ones with .gz are compressed but less should be able to show then anyway:

less /var/log/apt/history.log
less /var/log/apt/history.log.1.gz

As you are interested mainly in new installs, try this (also with history.log):

less /var/log/apt/history.log.1.gz | grep -B1 '^Install:'

(If less should not be configured to unpack *.gz files, zcat works in a similar way.)


Can I use the previous instructions for the new Eclipse installation?

Just follow the steps from "How do I install Eclipse Indigo 3.7.1". From eclipse perspective this is completely version independent.


sudden shutdown Ubuntu 16.04 - Dell inspiron 13 7000

It sounds like a bad battery. But lets try and reset the power manager.

Unplug the computer from AC, and remove the battery (if it's removable). Hold down the power button for 10-15 seconds. Reinstall the battery and reconnect the AC adapter (if you wish) and see if that solves your shutdown problem.

You can also check the system log file by, in terminal, type more /var/log/syslog and find nearby the time that you had a shutdown. Look specifically for any temperature related messages. If found, it would indicate that your machine is overheating, causing the shutdowns.

There's also a BIOS (and a firmware) update available that might help. See http://www.dell.com/support/home/us/en/04/product-support/product/inspiron-13-7368-2-in-1-laptop/drivers, and select BIOS (or ALL) as the category.

Cheers, Al


It looks like a python package race condition, the class does exist (note: JanC, it's not always because the module is missing) you can see GenericLyric in lyrics/__init__.py but it's while it's importing init that it tried to import init. Bad race condition.

The fix is to get a programmer involved, to do that you should report the bug here:

https://bugs.launchpad.net/covergloobus

See also this guide:

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


Why can't mythtv backend see my HDHomeRun tuner?

The most common reasons for MythTV tuning issues are:

You didn't go though all the steps in mythtv-setup (specifically
steps 2, 3, and 4). These 3 steps define the tuner, data, and then
connect the tuner to the data. All 3 of these steps are required.
You set your tuner to use multiplexing (number of recordings > 1)
and it doesn't support multiplexing. This is done in step 2 of
MythTV setup (in the Advanced settings section I believe).


Ubuntu Crashes Evertime I Open System Settings

sudo apt-get install gnome-control-center

This will re-install system settings.


Run Eclipse using the search (super button)

You need to create .desktop file for your program (eclipse.desktop in your case). Then put it to /usr/share/applications directory or ~/.local/share/applications if you want it to be accessible for one user only. It is easier to create the file on the desktop first and test it before copying to its destined directory.

Basic stucture of a .desktop file is something like this:

[Desktop Entry]
Type=Application
Encoding=UTF-8
Name=Sample Application Name
Comment=A sample application
Exec=application
Icon=application.png
Terminal=false

In Exec field you put a command you want to run (eclipse). I think all other fields are self descriptive. If you want more detailed information about .desktop file then there is a lot of info online.


Can't get wireless card to be recognized - Dell D630 - Broadcom BCM4311

The STA driver in 11.04 doesn't work due to a kernel issue.  You will have to install the B43xx firmware.  Just install firmware-b43-installer from the software center or synaptic.

You can also do it from the command line.

sudo apt-get install firmware-b43-installer


Change /mnt/data owner and group to yourself like this:

sudo chown basement21.basement21 /mnt/data

And allow only you to read and write, and your personal group to only read:

sudo chmod 750 /mnt/data


You can press the middle mouse button to directly paste into the terminal at the cursor position.


in short, first install bumblebee:

sudo apt-get install bumblebee bumblebee-nvidia

then you can run steam with your nvidia graphics:

optirun steam

this process will allow you to utilize Optimus (that's whats bumblebee is for) and then you can manually run applications with your nvidia card using the optirun command.


How to put Messsenger on top of full screen video?

In Ubuntu just Right-Click on the Title Bar of the Chat Client window and select the option "Always On Top". The Window will now remain on Top of all other Windows so you can Fullscreen a Video and still continue to chat.

EDIT: Oh I see. The problem here is Flash. Flash puts itself on top of everything else no matter what. The only way around that is to not use the Flash Player's Fullscreen button but instead zoom in on the player while it's still in the browser window. In Firefox CTRL+- Zooms Out, CTRL+ + Zooms In, and CTRL+0 Returns to Default Zoom.


Unable to view or edit etc/apt/sources.list

Path you gave on the nano is totally wrong. It's not etc/apt/sources.list, it's /etc/apt/sources.list. You forget the / symbol before etc. The below command will open /etc/apt/sources.list file through nano editor,

sudo nano /etc/apt/sources.list

If you gave the file path wrongly, nano will open an empty window like above.


USB file transfer painfully slow - is this a solution in some cases?

This totally sounds like a disk/filesystem issue, especially since the problem could be seen when doing large file operations (downloading from usb/internet), and since it went away when you nuked the entire disk and reformatted.

People here could probably give you a better answer if you gave more info about your disk setup when you had the dual boot config.


Print selected columns from a file if the row is mentioned in another file

Let's call your files datafile.txt (main data) and listfile.txt (gene names).
First extract all the lines from datafile.txt whose name appears in listfile.txt
grep -f listfile.txt datafile.txt > temp.txt

now use awk to extract the columns you need from temp.txt
awk -F, '{print $1,$3,$4,$5}'

(and remove the temp.txt file)
You can do away with temp file by piping the grep into awk directly.


I suspect your problem might not be with Krita, but some other setting or software.
I recommend installing and running the program atop. It allows you to check which bottleneck your computer is hitting: CPU, general disk IO, disk IO due to swapping, network etc. Here are the steps:

Press Ctrl + Alt + T to open a new Terminal window
Run sudo apt install atop
Run sudo atop
Wait until the "activity since boot" disappears.
Look for red text - this is your culprit.


not able to execute a compiled file - "permission denied"

try to do a chmod a+x rget to activate the execution permission.
If the file is on NTFS or FAT, you have to change mounting options in fstab


How to install a library when I have its source code?

The recommended way to install a library which was downloaded in its source code form is:

Assuming you are in the home folder, extract the .tar, .tar.gz, .tar.bz2, .tar.xz file using,

tar xf source_filename
Go to the folder /home/some_user/libxxx/ (the folder into which the previous tar command extracted the files)
Run,

./configure --prefix=/usr/local

make

sudo make install

This installs the library in '/usr/local' which is the recommended path according to the convention when you are not installing a software via any package manager. Also, this will not pollute the existing libraries in '/usr/lib' which makes maintenance easy in case you wish to uninstall the library in future.


Ubuntu 20.04 - Terminus font not working anymore

Pango stopped supporting old x11 fonts between versions 1.43 and 1.44, breaking them for all gtk apps.


Show the Unity Launcher, when desktop is opened

I know you said you weren't looking for a script or a shortcut, but you have to press or click on something to maximize the window.

There is another post asking the same thing that was resolved with a script and a key-binding. The thing is, the work is already done. You just need to copy the script and set the input key. What is the reason this won't work for you?

Previous solution


Please read file BootChess.txt in the archive you downloaded, everything is explained in section "6.1 - FAQ and remaining questions".

Most likely you want to do this:

  -if you have first 487b version (do not change any flags) : x86 equ 1                         ; x86=1 PC/emu vs. win32b/(DOS)Box saf equ 0                         ;
  saf=0 +queening -exotic failsafe
  -if you have second 468b version (change these flags) : gui equ 0           ; gui=1 x86=1 p2q=1 510b+ OK pad OK gui OK vbr- OK queen x86 equ 0
  ; gui=1 x86=1 p2q=0 498b+ OK pad OK gui OK vbr+ NO queen p2q equ 0
  ; gui=1 x86=0 p2q=1 504b  NO pad OK gui NO vbr- OK queen to gui equ 1
  ; gui=1 x86=1 p2q=1 510b+ OK pad OK gui OK vbr- OK queen x86 equ 1
  ; gui=1 x86=1 p2q=0 498b+ OK pad OK gui OK vbr+ NO queen p2q equ 1
  ; gui=1 x86=0 p2q=1 504b  NO pad OK gui NO vbr- OK queen

From BootChess.txt in archive:

  Q : How to assemble and test BootChess on real hardware ?    A :
  download program "fasm" flat assembler 16-bit version
       1)assemble with "fasm BootChess.asm"
         make sure preprocessor flag "x86 equ 1" in BootChess.asm
       2)write physical floppy boot sector as above
         on Linux type "dd if=BootChess.bin /dev/fd0 bs=512 count=1"
         on Windows type "partcopy BootChess.bin 0 200 -f0"
         or type "dd.exe if=BootChess.bin of=\.\a: bs=512 count=1"
       3)set BIOS boot order 1st Boot Device to "Floppy" and reboot
       BootChess launches...

And you get this: https://www.youtube.com/watch?v=mlLgOLmQg_g

Enter from keyboard string H7H5 for example.

Since there are no calls other than BIOS, it ought to run also as 16-bit binary on Linux, but I'm not sure it's been tested.


From the man page of ls:

  -g     like -l, but do not list owner

This would prevent the owner name from being listed. So what you intend to do is probably this:

ls --full-time -Gg

Also if you would like to see only a few desired columns, do ls -l and choose the columns using this:

ls -l | awk {'print $column_no'}

For example, if you only want the filename and size, do this:

ls -l | awk {'print $5" "$9'}

Source:

Formatting output of ls


Problem typing password when running sudo in terminal

I know this may sound stupid, but have you tried turning on/off caps lock?

Also (it's hard to tell from your english, sorry) but it sounds like you can't see the password. This is normal, you aren't supposed to see anything. Keep typing you password and press enter :)

EDIT Also, have you tried swapping keyboards? Maybe the keyboard is the problem.


Launch command in gnome-terminal, then close gnome-terminal without ending executed command?

Solution to your problem

The right solution here is to omit calling gnome-terminal and bash and even setting an unneeded variable in the first place, all of that is not needed in your case:

mpv -- "$(yad --entry)"

I added quotes to handle the URL correctly, this ensures it can contain e.g. whitespaces and ampersand signs (&) and the command still works. -- tells mpv to stop looking for options and treats whatever you choose to give it as an argument instead. Image the common case where you have a file named --version in the directory you start mpv from and just enter this filename, how can mpv know whether to show you its version string or open the file?

Answer to your question

nohup or disown can be used to detach a process from the shell that started it, see Differences between "<command> & disown" and "nohup <command> & disown".

In your case the correct solution would be:

gnome-terminal -e nohup mpv -- "$(yad --entry)"

However for a much better solution see above.


How to redirect output with color in gedit

Most probably not. There might be an option or a plugin in gedit that allows it to interpret this sort of ANSI color escape code, but that's unlikely since the point of those codes is to display color in terminal-based tools, not a GUI tool like gedit.

I suggest you simply use a terminal based tool to read your files instead. For example, you can use less -R which can interpret color codes correctly:

less -R  ~/Desktop/color.log


I have faced the same problem.
Solution: Boot into BIOS and go to bootable devices and increase the priority of Ubuntu partition than that of Windows. Save the change and reboot.
Now you will see the GRUB boot menu and you should also see boot 'To Windows' option on GRUB menu, if not, then boot into Ubuntu, open terminal and type sudo update-grub it will ask for the password, type in your password and click enter and reboot. Next time it will boot into GRUB and you will also see the Boot into Windows option.
Have a nice day.


You may look this previous post of the same problem like you. I thin it will help you and solve your problem.
How do I run a script at start up?


Your mac address are being shown under ether lines.

ether 28:d2:44:e8:30:6a

and

ether 38:b1:db:c7:a5:27

You can even use nmcli to get your mac address:

nmcli device show enp3s0 | grep -i hw

or

nmcli device show wlp4s0 | grep -i hw

both outputs will be similar to:

GENERAL.HWADDR:      38:b1:db:c7:a5:27


Ubuntu 16.04 Xenial Xerus - change from release to stable channel

No, you don't need to change anything.

If you want you can check the package sources in the file /etc/apt/sources.list:

All lines that don't start with a # should have something with xenial in the third field (after the URL), for example

deb http://archive.ubuntu.com/ubuntu xenial main restricted

or

deb-src http://de.archive.ubuntu.com/ubuntu xenial-updates multiverse


Are you using Kubuntu or another variant with KDE installed over it? Which version are you running?

I found this repository on LaunchPad but I have doubts that this will work on a recent version of Ubuntu because it has not been updated since 2013 and the builds seem to be failing.

I also found this deb file which was designed for Dapper Drake. It also has a low chance of working because Dapper Drake is a very old release but it's worth a try.

Hopefully one of these things works for you!


Is there anyway I can stop the panel from showing up when I switch focus to a different application?

You could try upgrading to 12.04, there have been many improvements to the way dual screens are handled, and you can control better how the launcher works with dual screen (on System Settings > Displays, and System Settings > Appearance > Behaviour).  If it still doesn't work for you can you add more detail to the question please?  I am not sure exactly what you are seeing.  But try it in 12.04 first.


I have 18.04 LTS 32 bit while there's no such version on the official site

There is no Ubuntu 18.04 LTS desktop ISO, that was announced years ago and hasn't changed (wasn't any for 17.10 either).
Yes, Ubuntu 18.04 LTS is supported on x86 (flavor ISOs exist, plus netboot), but there is no i386/x86 desktop ISO except for amd64.
Some flavors (e.g. Lubuntu & Xubuntu) supported 18.10 fully for x86, and even continued into the 19.04 cycle for alpha ISOs (last ISO was very early Dec-2018 for Xubuntu, late Dec-2018 for Lubuntu) which had you installed either, your system would have had all upgraded packages for the life of 19.04.
The x86 upgrades were disabled completely just prior to 19.10's actual release (https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1845714)
If you're using x86/32-bit though, your best supported bet is 18.04 LTS, as it'll have 5 years of support for main repository (server, default desktop) and 3 years for flavors.


For people who are getting this issue now, Seiko Epson Corp provides a free software printer driver package for Linux that supports a large number of Epson printers.

It's available to Ubuntu as printer-driver-escpr.

If you're currently stuck in the printer dialog, you can safely kill it.  Then you'll want to install a driver package manually, which should allow you to pick a local driver and avoid this issue.

Step 1: Clean up files so that we can install printer drivers without errors regarding debconf/config.dat being locked.
$ sudo rm /var/cache/debconf/*dat

Step 2: Install printer-driver-escpr.
$ sudo apt-get install printer-driver-escpr

Step 3: Start up your printer utility and select your printer.

Step 4: Choose to install a "Local Driver", select the model closest to your printer, and continue.

You should now be able to use your printer.  Verified on LXLE 14.04, derived from Lubuntu/Ubuntu 14.04 LTS.


Why can't I get my Dell Latitude to output to an external monitor at 2560x1440

From what I understand, "Optimus" is the technology, which decides, when to use the dedicated Nvidia graphics card and when to use the on-board intel graphics chip.

https://secure.wikimedia.org/wikipedia/en/wiki/Nvidia_Optimus:

  For now, Nvidia has no plans to support Optimus on Linux. This makes hardware acceleration impossible by the Nvidia adapter. However, Martin Juhl is working on an Open source alternative called Bumblebee (https://github.com/MrMEEE/bumblebee).

You might want to check out the Bumblebee project, it seems to me, that this is, what you need to use your Nvidia graphics card.


Can't format external HDD after removing it from computer

As I can read of your screen-shot the partitions are still mounted in your Linux, open a terminal with ctrl+alt+t and unmount them with issuing the following command for each partition which still shows a mount-point:

sudo umount <mount-point>

Or as alternative you can right click their entries in the partition list and select unmount.


How to replace string containing file path using sed

Using sed with pattern grouping:

sed -r 's/(.*=)D(:\\[^\]+)(\\.*)/\1E\21\3/' file.txt

All () are indicating pattern groups, the purpose of grouping is to use them in the replacement by just using \# reference (replace # with group number, incrementing from 1, left to right)
(.*=) will match the portion before first D, this is referenced as group 1 i.e. \1 in replacement
(:\\[^\]+) matches upto the second \ after D, this is \2
(\\.*) matches everything else after second \ (including), this is \3

Example:

$ cat file.txt
Dir=D:\test\foo
Dir=D:\test\bar

$ sed -r 's/(.*=)D(:\\[^\]+)(\\.*)/\1E\21\3/' file.txt
Dir=E:\test1\foo
Dir=E:\test1\bar

If you have multiple occurrences and you want to replace them all:

$ cat file.txt
Dir=D:\test\foo Dir=D:\bar\foo
Dir=D:\test\bar

$ sed -r 's/D(:\\)[^\]+/E\1test1/g' file.txt
Dir=E:\test1\foo Dir=E:\test1\foo
Dir=E:\test1\bar


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

Select the folder you want to link, then go to the top menu bar and select Bookmarks -> Add Bookmark.

When inside the folder that  you want to bookmark, go to the top menu bar and select Bookmarks -> Bookmark this location -- or  Ctrl+D.


Standard user can change the Date and Time

Not literally the answer you are asking for, but if your system is forgetting the time and / or date, you will probably need a new cmos battery on your motherboard. As this link explains, it sometimes helps to leave the computer on for a long(er) time to see if the battery is charging a bit, so it can remember the time & date a bit longer.

The link also describes how to change the battery.


How to apply a changelog file to packages in a PPA when building from recipe?

I asked this question on IRC (at #launchpad) and got the answer I was expecting:

No, it's not possible to prevent the creation of that changelog entry. It is necessary so that it can specify the appropriate autobuild version string (the one you define in the first line of the recipe file).

However, your changes should not be lost, just placed right after that entry.


What exactly are items in the /dev directory?

Everything in Linux is a file or a directory. Things in /dev are special files.

The majority of devices are either block or character devices; however other types of devices exist and can be created. In general, 'block devices' are devices that store or hold data, 'character devices' can be thought of as devices that transmit or transfer data. For example, diskette drives, hard drives and CD-ROM drives are all block devices while serial ports, mice and parallel printer ports are all character devices. There is a naming scheme of sorts but in the vast majority of cases these are completely illogical.

Devices are defined by type, such as 'block' or 'character', and 'major' and 'minor' number. The major number is used to categorize a device and the minor number is used to identify a specific device type. For example, all IDE device connected to the primary controller have a major number of 3. Master and slave devices, as well as individual partitions are further defined by the use of minor numbers.

Taken from Linux-Filesystem-Hierarchy

2 options:

Try

 cat < /dev/ttyS0

and see if that works.
You might solve this error by adding your user to the same group (ie. dialout).


You can access this "login" site almost always by typing in the gateway address into your webbrowser.

Open Terminal -> ifconfig.
Then open the Web-Browser and Type in the Gateway address und it should open the "login page"


How to install Cisco-AnyConnect-64bit.tar.gz?

Well, those are generic instruction for a generic .tgz package.

I found a quite simple guide here on how to specifically install Cisco AnyConnet on Debian/Ubuntu systems.


802.1q VLAN interface configuration on Ubuntu 12.04 Desktop

Install VLAN package on your computer:

sudo apt-get install vlan
Edit your /etc/network/interfaces file so it would contain the following:

  #The loopback network interface

auto lo
iface lo inet loopback

#This is a list of hotpluggable network interfaces.
#They will be activated automatically by the hotplug subsystem.

auto vlan500

  # VLAN 500

iface vlan500 inet static
address xxx.xxx.xxx.xxx
netmask xxx.xxx.xxx.xxx
network xxx.xxx.xxx.xxx
broadcast xxx.xxx.xxx.xxx
mtu 1500
vlan_raw_device eth0

Note: You have to replace my IP addresses, network masks and gateway IP address with your own.

3.Make sure that switch interface you are connected to configured with respective VLANs.

4.Restart your network interface:

sudo /etc/init.d/networking restart

You should see something like:

Set name-type for VLAN subsystem. Should be visible in /proc/net/vlan/config
Added VLAN with VID == 500 to IF -:eth0:-


How to search through all keyboard shortcuts that use a certain key?

You can view the set keyboard shortcuts for Unity and Gnome through

gsettings list-recursively | awk '/hotkey/||/keybinding/||/media-key/' | less

and

dconf dump / | awk '/keybindings/ || /media-keys/{print; getline; print }'

I suggest you play around with those commands, try filtering out the output in different ways, but in short it's all in gsettings and dconf


Ubuntu 15.10 after restart Wi-Fi, usb ports, LAN, not working! Please help

You might have installed a new kernel, which doesn't support your configuration. Check if you have the previous kernel listed in the boot list and try loading it to see if it still works.


Transfering files between two Ubuntu PC's using a crossover cable?

I do have a crossover cable but sure, a normal UTP cable will serve as well. Ubuntu will automatically adapt to the UTP cable you use.
I had your exact same question and found the the following solution after looking up for "Link-Local Only" on this forum.
You have 2 computers and you want to link them in the most easy way. I use Ubuntu 20.4 on both.
Put your cable in the network slots of both computers.
Go to the settings panel (click somewhere in the upper right corner and click 'Settings') on one of your computers.
Click in the settings panel on Network.
In the box 'Wired' you see "Connected - 100 Mb/s" and the switch is to the right. If not, take the cable out and connect him afterwards.
Click on the cogwheel icon in this box.
This opens a window "Wired", click the tab IPv4
Now you see several IPv4 Methods. Choose "Link-Local Only". The DNS and Routes switches turn automatically on. Click Apply.
Open the window again and open the Details tab in this "Wired" window. Take notice of the IPv4 Address that shows up.
Now do the same at your other computer. Notice that this IPv4 address is not exactly the same.
Put your cable if it is not put already.
Both computers are now connected, if not something may be wrong with your cable. To confirm the connection open a terminal window and use the command "ping" followed by the IPv4 address of the other computer.
    Jan@mycomputername:~$ ping 169.254.112.194
    PING 169.254.112.194 (169.254.112.194) 56(84) bytes of data.
    64 bytes from 169.254.112.194: icmp_seq=1 ttl=64 time=0.219 ms
    64 bytes from 169.254.112.194: icmp_seq=2 ttl=64 time=0.319 ms
    64 bytes from 169.254.112.194: icmp_seq=3 ttl=64 time=0.450 ms

Type Ctrl+C to see the final result:
    ^C
     --- 169.254.112.194 ping statistics ---
    3 packets transmitted, 3 received, 0% packet loss, time 8194ms
    rtt min/avg/max/mdev = 0.219/0.368/0.456/0.084 ms

If you see 100% packet loss, something is not working. Reset the two computers and try a different order of connecting.
Now, to actually see the content of the other computer you need to install a server pogram at one of them. The best option is OpenSSH-server that you can install with this command in your terminal window:
    sudo apt-get install openssh-server

If that does not end with an error message, the openSSH server is up and running.
On your other computer go now to your files manager (formerly known as Nautilus) and open "Other Locations". There you see the option "Connect to Server". Enter as server address ssh:// followed by the name of the other computer (that is the name that appears after the @ in the terminal prompt) or the IPv4 address of the other computer. Click the Connect button. You will have to login with name and password of the other computer.
Now this computer is the socalled client computer and the other (where the OpenSSH-server is running) is your server. In the file manager of the client you will see your server computer and using this file manager you can move/transfer, copy and delete files in both computers.


Creating an encrypted backups for my entire home directory

From tar --help:

-f, --file=ARCHIVE         use archive file or device ARCHIVE

With your f option tar is expecting an output file, like foo.tar.gz. So this should work:

tar -zcv /home/rehab | gpg --symmetric --cipher-algo aes256 -o /var/backups/myhome.tar.gz.gpg

Mind the / in front of /var