Macbook Air 4,2: "Boot error" with 12.04 live USB

Seems my memory is bad: Using unetbootin with a msdos partition table + mac iso + dd'ing to harddrive partition actually made it boot.


Lets analyze your homework: -rwxr-xr-x, break them into three parts -rwx|r-x|r-x:

rwx: read, write and execute for user or owner
r-x: read, no write, and execute for group members
r-x: same as in 2 but this time for every other person aka others.

No you will need to run the command using the change permission program chmod like so:

chmod 755 filename

Explained:

change the permission to:

- user: 7 => r(4), w(2), x(1)
- group: 5 => r(4), -, x(1)
- others: r(4), -, x(1)

Now you have to own that file or folder to do this or be in the sudo group.


Just set up a simple but signed repository on a webserver. Because most other tutorials are somewhat dated or cumbersome, I'll try to replicate the procedure here. The initial configuration takes a bit of effort, but the simple build script keeps it easy to manage. And you can just drop in new *.deb files, then update, or let a cron job handle that.

Generate some signing keys

First you need to create a gpg signing key for packages and your repository. Make it a (4) RSA signing key, no password, and give it a unique $KEYNAME when asked for. (Further examples assume "dpkg1" as keyname.)

 gpg --gen-key
 gpg -a --export-secret-key dpkg1 > secret.gpg
 gpg -a --export dpkg1            > public.gpg

I said no password, because your webserver has no builtin monkey to type it in repeatedly. And the signed packages and repository are only meant to satisfy the update-managers complaints about that. Just upload both keys to the new /apt/ repository directory on your webserver, but delete the secret.gpg key after initialization.

Update CGI script

This is the simple update shell/CGI script for it:

#!/bin/sh
echo Status: 200 Okay
echo Content-Type: text/plain
echo
echo Rebuilding APT repository:

{
  #-- settings
  export GNUPGHOME=/var/www/usr12345/files
  export KEYNAME=dpkg1
  #-- one-time setup
  if [ ! -e "$GNUPGHOME/secring.gpg" ] ; then
     gpg --import -v -v ./secret.gpg
     gpg --import -v -v ./public.gpg
     gpg --list-keys
  fi

  #-- symlink .deb files from adjacent sub-directories
  find .. -name '*.deb' -exec ln -s '{}' . \;

  #-- build Packages file
  apt-ftparchive packages . > Packages
  bzip2 -kf Packages

  #-- signed Release file
  apt-ftparchive release . > Release
  gpg --yes -abs -u $KEYNAME -o Release.gpg Release

} 2>&1

The three gpg lines only need to be executed once, to initialize the GPG setup in some directory $GNUPGHOME (above the document root). Delete only the secret.gpg after success.

One unique feature of this small shell script is that it accepts any *.deb files that you drop in, but also searches recursively (starting from one level up) for others, and symlinks them in. (Needs .htaccess Options FollowSymLinks eventually.)

You can either execute this script manually as CGI or per cron-job. But hide it, or better yet move it out of the document root.

Because it's a "trivial" apt repository it needs the following apt-sources.list entry:

deb http://example.org/deb/  ./    # Simple signed repo

That's suitable for single-architecture repositories, and if you don't expect hundreds of packages.

Package signing

Signing your individual packages is also trivial, once you've set up your gpg keys:

dpkg-sig -k dpkg1 -s builder *.deb

(This should be done on the workstation where packages are built, not on the repository webserver.)

Unsigned repository

If you don't need signed packages, then you could slash the update script down to just:

  dpkg-scanpackages . > Packages
  bzip2 -kf Packages

Which can still be used by average users, but needs a custom flag for apt.sources:

deb [trusted=yes] http://apt.example.org/deb/ ./

But please don't use the trusted=yes flag habitually for everything, or if you're not actually sure about the package origin.

For usability

For end users, just drop a HEADER.html into the repository directory. Apaches mod_auto_index will prepend that note:

http://example.org/apt/

Add this repository to /etc/apt/sources.list as:

deb http://example.org/apt/ ./  # example repo

Import verification key with:

wget -q http://http://example.org/apt/public.gpg -O- | sudo apt-key add -

Alternatives

There are a few tools to automate repository management these days. And there are even repository online hosters and package build services (gemfury, packagecloud, bintray etc.)

A rather convenient alternative is prm. It's a Ruby script, which builds complex APT and YUM repos. (But let's just hope RPM finally dies out sometime soon..) - It's best installed per gem install prm.
And I've also written a small script to automate this similarly: http://apt.include-once.org/apt-phparchive - Please not that it's not overly robust and written in PHP (for once, this is coincidental), and was originally meant for DEB, and RPM-over-APT and Phar bundles.

Since this is closely related to the original question, there are also tools to build Debian packages more easily. Somewhat outdated: EPM. Much more contempoary: FPM. And my personal fork thereof: XPM (more lazy approach for packaging scripting language apps.)


Is 240 a major number in Ubuntu 20.04.2 LTS?

If the major version of 240 is already used for a character device, then it should be present in /dev/char. Example:
doug@s19:~/temp-k-git/linux$ ls -l /dev/char | grep 240:
lrwxrwxrwx 1 root root  8 May 10 20:23 240:0 -> ../nvme0
doug@s19:~/temp-k-git/linux$

See the devices.txt document in the kernel tree.
I assume your "resource busy" error is because the 240 major version number is already used by something.
EDIT: Perhaps a better way to see what major numbers are already used is to look at /proc/devices. Example:
doug@s19:~/c$ cat /proc/devices
Character devices:
  1 mem
  4 /dev/vc/0
  4 tty
  4 ttyS
  5 /dev/tty
  5 /dev/console
  5 /dev/ptmx
  5 ttyprintk
  7 vcs
 10 misc
 13 input
 21 sg
 29 fb
 89 i2c
108 ppp
116 alsa
128 ptm
136 pts
180 usb
189 usb_device
202 cpu/msr
203 cpu/cpuid
204 ttyMAX
226 drm
234 mei
235 hidraw
236 aux
237 cec
238 ttyDBC
239 lirc
240 nvme-generic
241 nvme
242 vfio
243 bsg
244 watchdog
245 remoteproc
246 ptp
247 pps
248 rtc
249 dma_heap
250 dax
251 dimmctl
252 ndctl
253 tpm
254 gpiochip

Block devices:
  7 loop
  8 sd
  9 md
 11 sr
 65 sd
 66 sd
 67 sd
 68 sd
 69 sd
 70 sd
 71 sd
128 sd
129 sd
130 sd
131 sd
132 sd
133 sd
134 sd
135 sd
253 device-mapper
254 mdp
259 blkext

Which shows cec, as per the comment, but with major number 237 on my system.
The suggestion for the users is to use dynamic assignment of the major instead of static, letting the system decide. Reference.


If you just want to rescue your data, proceed this way:

Start Ubuntu from USB or DVD. It will run a fully working live system. No need to install or modify any partition!
The rescue system is meant to repair Ubuntu. not Windows.

After it has booted up, you can start the file manager. It should show your harddrive and you will be able to browse it's content.
If it's not showing here, you should install it into another pc or buy a usb-s-ata connector.


There are two ways to add ppstream to your system either by installing the deb file which you can download from there site

ppstream deb file download

Or you can add this ppa ppa:cnav/ppa

there are many ways to add a ppa source to Ubuntu which are listed here

Once this has been added and your sources have been updated you can search and install ppstream from Ubuntu Software Center.

you can update your software sources by using this command sudo apt-get update in the terminal or by pressing alt+f2 and filling the command in the box provided.

Edit

To install using apt-get install first open a terminal by either searching for it with the dash or if you are using the classic interface it is located in the accessories menu.

When you have opened terminal use this command

sudo apt-get update && sudo apt-get install ppstream

If you see any errors please add them to your question or a comment so we can help further.

Hope this helps


How could I shutdown a remote host, in my network thru ssh, with a local host?

Assuming that the user you are going to use in remote.host is the same you use in local.host
In order to do that you have to first authorize your local.host to connect to you remote.host with no password.
To do that you have to: (as described here)

Step 1: Install ssh

sudo apt-get install ssh

Step 2: Create public and private keys using ssh-key-gen on local-host

On your local host, enter this command:

ssh-keygen

You should save the generated key in:

/home/yourusername/.ssh/id_rsa

Press enter twice to leave the passphrase empty.

Your identification has been saved in /home/yourusername/.ssh/id_rsa.
Your public key has been saved in /home/yourusername/.ssh/id_rsa.pub.
The key fingerprint is:
XX:XX:XX:xX:XX:xX:XX:XX:XX:XX:XX:XX:XX:XX yourusername@local-host

Step 3: Copy the public key to remote-host using ssh-copy-id

yourusername@local-host$ ssh-copy-id -i ~/.ssh/id_rsa.pub remote-host
yourusername@remote-host's password:

Now try logging into the machine, with "ssh remote-host", and check in:

.ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

Note: ssh-copy-id appends the keys to the remote-host’s /home/yourusername/.ssh/authorized_key

Step 4: Login to remote-host without entering the password

ssh remote-host
yourusername@remote.host:~$

Access to remote-host with no password. Success!

Now you have to be able to execute the sudo shutdown -P 0 with no password.

Modify /etc/sudoers on remote.host with visudo

That way user "yourusername" can execute the shutdown command with no password asked.
Login to the remote host.

ssh remote.host

Run:

sudo visudo

By running visudo, it leads to edit /etc/sudoers.
Adding the line below to that file.

yourusername ALL = NOPASSWD: /sbin/shutdown

Done that, get back to your local.host
Create a new empty file and paste this line, modifying the remote.host's name

ssh remote.host sudo shutdown -P 0

Save and close it, go to it's Properties slide to Permissions, and tic the execute this file as a program

Script Done!


Try this:
Start in text-only mode

Switch on your computer. Wait until the BIOS has finished loading, and press and hold Shift, which will bring up the Grub menu.

Select the line which starts with Advanced options.

Select the line ending with (recovery mode)

Press Return and your machine will begin the boot process.

After a few moments, your PC should display a menu with a number of options, including Drop to root shell prompt. Press Return with this option highlighted.

The PC will start in a terminal.

Run these commands:

Mount partitions in read-write mode

mount -o remount,rw /
mount --all

Update repositories

apt update

Install aptitude and deborphan

apt install --reinstall aptitude deborphan

Eliminate the components of unity that are not necessary in gnome

aptitude remove '?and(?reverse-depends(unity),?not(?reverse-depends(?exact-name(gnome))))'

Reinstall gnome

apt install --reinstall gnome

Eliminate orphan packages

deborphan
apt --purge remove $(deborphan)
deborphan --libdevel
apt --purge remove $(deborphan --libdevel)
deborphan --find-config
dpkg --purge $(deborphan --find-config)

Remove unnecessary packages

apt autoremove

Remove downloaded packages

apt clean

Restart system

reboot


Screen emulation is not available on this page

On chrome://flags I enabled the "Override software rendering list" option, which solved the issue.


I do agree that a re-install will be easier and it will have a predicted result (a total recreation of all permissions) but it is possible to do this without a re-install using "acl". On the desktop editions "acl" is installed by default.

Now the problem is that because you messed up "sudo" and probably did not create a collection of permissions you will need an outside source.  If you have another system you can make these files yourself with the command below. If you do not have a 2nd machine I created a permissions file of all the files in /usr/ (/etc/ and /var/ are included below too) with

getfacl -R / > /tmp/permissions_usr.acl

and uploaded it to dropbox (12Mb). Download it and store it somewhere (I will assume /tmp/)With the command

setfacl --restore=/tmp/permissions_usr.acl

you can restore the file properties. But you will need a root prompt for this so will have to reboot into recovery mode from grub (see How do I boot into recovery mode?)

Same permissions file created for

etc (1.1 Mb)
var (0.1 Mb)

These 3 files are all like this:

$more permissions_etc.acl
# file: etc
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

# file: etc/signond.conf
# owner: root
# group: root
user::rw-
group::r--
other::r--

# file: etc/hp
# owner: root
# group: root
user::rwx
group::r-x
other::r-x

...


I solved it by using i8kutil package which is used for controlling the fans in Dell laptops.

Use this solution found at this webpage: How to solve Dell laptops fan issues in Ubuntu.

I used this config for my Dell 3521 with Radeon HD7670M 1GB dedicated graphics.

# Sample i8kmon configuration file (/etc/i8kmon.conf, ~/.i8kmon).
# External program to control the fans
set config(i8kfan)  /usr/bin/i8kfan
# Run as daemon, override with --daemon option
set config(daemon) 0
# Automatic fan control, override with --auto option
set config(auto) 1
set config(nouserconfig) 1
# Applet geometry, override with --geometry option
set config(geometry)    {48x48}
# Report status on stdout, override with --verbose option
set config(verbose) 1
# Status check timeout (seconds), override with --timeout option
set config(timeout) 5
# Temperature display unit (C/F), override with --unit option
set config(unit)    C
# Temperature threshold at which the temperature is displayed in red
set config(t_high)  80
# Temperature thresholds: {fan_speeds low_ac high_ac low_batt high_batt}
# These were tested on the I8000. If you have a different Dell laptop model
# you should check the BIOS temperature monitoring and set the appropriate
# thresholds here. In doubt start with low values and gradually rise them
# until the fans are not always on when the cpu is idle.
set config(0)   {{-1 0}  -1  60  -1  65}
set config(1)   {{-1 1}  50  70  55  75}
set config(2)   {{-1 1}  60  80  65  85}
set config(3)   {{-1 2}  70 128  75 128}
# end of file

After configuring run this in terminal on every boot up:

i8kmon --auto --verbose --nouserconfig


I can't get my ubuntu server VirtualBox guest with bridged adapter seen outside of my lan, although port forwarded to 80

I ran into this same exact problem a while ago. After spending way too much time troubleshooting and trying to figure out why it wouldn't work, I found out it was not a problem with my configuration.

Most of the time, your ISP (internet service provider) blocks calls to port 80. (Example: List of ports blocked by Cox)

This means that although you are redirecting calls to port 80 to your machine, they are never actually receiving those calls to begin with.

Try to google your ISP and see if they block any ports. Then try forwarding to a port they don't block, and append that port to the url. (Example: forward to port 1234, do http:// your ip:1234). If that works, but port 80 doesn't then that is the problem.


Intel Centrino Wireless N 2230 driver problem

You have a common conundrum; a newer wireless device and an older Ubuntu version. The PCI.ID for your device isn't included in the iwlagn version in 10.04. I suggest you upgrade to Ubuntu 12.04.3 LTS where your wireless will work perfectly with no further steps.

If you are committed to Ubuntu 10.04, please get a wired ethernet connection, open a terminal and do:

sudo apt-get install linux-backports-modules-wireless-3.3-lucid-generic

Detach the ethernet. After a reboot, your wireless should be working.


Steam Library-Must be on a filesystem mounted with execute permissions

This Steam error occurs because your drive is mounted by root and you don't have execute permissions on the drive (I think). You can use the disks app to change this.

Search disks in the dash, highlight your drive and under the usage image is a small cog icon, click this and edit mount options, now make your settings look like this

Leave the rest as it is and reboot. Now your drive can be found in /mnt and is auto mounted as your user at boot.

This is how I fix this error in 14.04, NTFS drive.


Why Thunderbird is taking too much space

It seems as if you are using IMAP for your mail account.

You can compress your mail to save space.

Most likely your issue is that you have deleted items but not purged them which means that the messages you have deleted appear as they are gone but in fact they are still around, you will need to purge them to physically remove the items you have deleted, checkout this link for more info:

http://kb.mozillazine.org/Compacting_folders


How to grant application access for Facebook account

A note upfront: It appears that Empathy doesn't support Facebook's messaging service, but Pidgin, a similar multi-messaging client based on the same library libpurple, does with a plug-in as described below.

  The purple-facebook plugin is a replacement for the builtin Facebook XMPP plugin. Facebook is in the process of shutting down their XMPP service, which will inevitably break existing support.

(Source)

The following instructions are written for Pidgin and while they should work for the same for Empathy in theory (since they're both based on libpurple), people report that Empathy doesn't accept this plug-in for some reason.

  To install purple-facebook in Ubuntu, Linux Mint and derivatives, you can use its official repository. To add the repository and install the plugin, use the following commands:

  sudo add-apt-repository "deb http://download.opensuse.org/repositories/home:/jgeboski/xUbuntu_$(lsb_release -rs)/ /"
wget -O- 'https://jgeboski.github.io/obs.key' | sudo apt-key add -
sudo apt-get update
sudo apt-get install purple-facebook

  If you don’t want to add the PPA, you can download the DEB from HERE (but you won’t receive any updates unless you add the repository). Or, grab the source and build it yourself. […]

  Once installed, add a new account in Pidgin (Accounts > Manage Accounts > Add) and in the Protocol dropdown, select “Facebook”
  (important: NOT “Facebook (XMPP)”):

  Pidgin Facebook I should also mention that in the username field, you can enter either your emil, your Facebook username or phone number associated with your Facebook account.

(Source with some modifications)

Official installation instructions

  As of October 18, 2015, jgeboski's GSoC work was merged into the mainline Pidgin project. It will appear in the next major release of Pidgin.

This means, future libpurple versions in Ubuntu (and probably earlier in the Pidgin PPA) will include purple-facebook and supersede the above procedure.


Which packages should be installed on Ubuntu server so it will be able to play video?

To be able to play most audio and video formats, install Ubuntu Restricted Extras:
sudo apt-get install ubuntu-restricted-extras

Edit
To find out which codec you need:
sudo apt-get install libav-tools
ffprobe -show_streams "file.mp4"

It'll probably be AAC for audo and H.264 for video.
Support to decode MPEG-4 AAC is provided by gstreamer1.0-libav and to decode H.264 there is gstreamr0.10-ffmpeg:

sudo apt-get install gstreamer1.0-libav gstreamer0.10-ffmpeg


How can I save the state of a virtual machine in GNOME Boxes?

Open Boxes and right-click the stopped virtual machine, then select and click Properties.

If you want to do it while the machine is running, select and click Properties on the top right.

Open the Snapshots tab and click on the + sign to create a new snapshot of the machine.

By the way, I recommend to create new snapshots when the virtual machine is not running.


drivers | is modprobe necessary when installing nvidia drivers?

https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa add this ppa and install 355 and then reboot, you will need modprobe if you need to do CUDA or opencl.


Removing gnome-screensaver also wants to remove gnome-core

You do not really need to remove gnome-screensaver , disable gnome-screensaver (and enable xscreensaver) in gnome-session-properties

If you really wish to remove it you may as gnome and gnome-core are meta packages, similar to ubuntu-desktop. meta packages are a list of packages to be installed.

See Ubuntu Wiki Metapackages for details


Disabling secure boot for Linux these days is usually required when loading unsigned kernel modules, e.g. some proprietary graphics drivers.

With secure boot active, this is not possible, so if you need these you have to disable it.

When deciding to do so, carefully consider if you trust the source of the module.

There will probably be different opinions on this, personally I think it is a good idea to have it enabled, but this is not always practical (on my gaming computer, it is disabled).

In general I'd say just use the same judgement as you would when downloading a random .deb package from the internet and you should be fine.


There is recovery mode on desktop versions but I don't know whether it exists on sever versions. It can drop a rootshell, so maybe stop reading my answer and check out whether it exists.

If it doesn't, you can chroot into the system if you can boot into a live session. So do the latter and execute these commands:

sudo mount /dev/sdxY /mnt
sudo mount /dev/sdzY /mnt/boot # THIS LINE ONLY WHEN USING A DEDICATED BOOT PARTITION!!!
sudo mount /dev/sdwY /mnt/boot/efi # THIS LINE ONLY WHEN USING UEFI!!!
sudo mount -t devtmpfs /dev /mnt/dev
sudo mount -t devpts /dev/pts /mnt/dev/pts
sudo mount -t sysfs /sys /mnt/sys
sudo mount -t proc /proc /mnt/proc
sudo mount -t tmpfs /run /mnt/run

Replace /dev/sdxY with your system partition, /dev/sdzY with your boot partition, and /dev/sdwY with your efi partition (but why the hell would you be using uefi anyway!?).

And then run sudo chroot /mnt /bin/bash to chroot into the other system. You can exit via exit.


Window preview is not working in DockbarX

To use the window previews,you need CompizConfig Settings Manager
sudo apt-get install compizconfig-settings-manager

Warning: What are some of the issues with CCSM and why would I want to avoid it?

Also in gnome enable KDE Compatibility plugin  System>>Preferences>>CompizConfig Settings Manager.

Once you enable this plugin, in DockBarX preferences goto Applications>>Accessories>>DockBarX>> Preference), on the Window List tab, enable Show Previews.


Abbyy fine reader like application for Ubuntu 13.04

You can use Abbyy OCR.

  ABBYY FineReader Engine CLI for Linux is a ready to use CLI tool based
  on ABBYY’s advanced Optical Character Recognition (OCR) technologies.
  The tool automates OCR and document conversion on Linux systems.

For more information, and to download it, visit their website.

Source:Ocr4Linux


Try using 'dig'

dig  omappedia.org

For me it returns:
(unnecessary lines omitted)

omappedia.org.        7200    IN  A   184.73.187.199

It does not respond to a ping,

If I go directly to the IP address (184.73.187.199) I end up at "university.pandaboard.org" indicating that it is either a loadbalancer, or a server running multiple sites.

You should not be able to access http://university.pandaboard.org/ either if the connection is terminated by your ISP on IP-level.

If you run 'dig' and get another IP address that may indicate that the DNS server you are using are either messed up or may intentionally give you a wrong answer.

Try changing to Googles DNS servers, 8.8.8.8 or 8.8.4.4 and see if you get another answer.


Bluetooth mouse no longer paired after resuming from suspend since upgrading to 13.10

Bluetooth settings are controlled from configuration files in /etc/bluetooth. For input devices we can define a timeout before a connection will be disconnected. To disable this open /etc/bluetooth/input.conf as root in an editor and either comment out the following line by adding # (as it is done in the example below), or set timeout value to 0:

#IdleTimeout=30 (set to 240)

Other timeouts that can be set in /etc/bluetooth/main.conf may not be affected in your case as they only play a role when a service may be interrupted (e.g. by bad signal strength) and will not be reconnected in case a timeout is set here. Default values for timeouts in main.conf are:

DiscoverableTimeout = 0 Set to whatever
AutoConnectTimeout = 0 Comment this out
PairableTimeout = 0 Set to whatever
PageTimeout = 8192

Also set RememberPowered to false in main.conf

Follow the above instructions to set a longer timeout for reconnect. About the unpairing, it is probably due to Ubuntu thinking the device is gone.

Source: Bluetooth mouse not auto-reconnecting


How to restart the wireless with a changed configuration on command line?

You must use:

nmcli nm wifi on/off

no nmcli c up/down.


How to update chromium daily builds manually

Install this ppa "Canonical Chromium Builds" team

  $ sudo add-apt-repository ppa:canonical-chromium-builds/stage
  $ apt-get update

Use build-dep action of aptitude before installing chromium-browser

  $ aptitude -v -V build-dep chromium-browser
  ..
  The following actions will resolve these dependencies:

     Upgrade the following packages:
  1)    ..
  Accept this solution? [Y/n/q/?] y
  ..
  $ sudo aptitude install chromium-browser

See also How to install latest package version of a ppa?


This code:

find . -maxdepth 1 -type f -name "*.txt" -exec sed -i.bak '1,4d' {} \;

actually works, the issue were:

The created file with the command wasn't made executable for that do:

chmod +x file.command

Then run the command from the terminal with:

./file.command


Installing clean Trusty Tar with MySQL 5.6 might contain corrupt package

This is likely due to not enough memory for MySQL Server 5.6. Try adding more RAM to your virtual machine in Vagrant:

config.vm.provider "virtualbox" do |v|
    v.memory = 1024
end

Tested with Vagrant 1.7.4 and ubuntu/trusty64 image.


Altering the backlight dim timeout on a Thinkpad laptop

I had this issue on a Thinkpad x220. The following message showed up in /var/log/dmesg:

  [   10.262915] thinkpad_acpi: Standard ACPI backlight interface
  available, not loading native one

You can tell linux to let a vendor specific driver (thinkpad_acpi) handle the backlight by passing the acpi_backlight=vendor option to the kernel.

To do this:

Edit /etc/default/grub
Add acpi_backlight=vendor to the list of options in GRUB_CMDLINE_LINUX_DEFAULT
Run sudo update-grub

The backlight is now managed by thinkpad_acpi and does not dim after 5 secs.


Nothing happens. You will just be able to run some demos (see /usr/share/doc/wayland-demos/README.Debian for how to start them).


The apt-get command requires root privileges, so you need to run it with sudo. For example:

sudo apt-get update

Then you can install your packages:

sudo apt-get install openjdk-7-jre-headless


Opera browser has free vpn function.
Opera don't presents in official ubuntu repository but could easily downloaded from official web site www.opera.com
In Security section of settings select VPN.
In address bar of browser you can use vpn location selector.


You could try a mirror that is closer to your geographical location, or use BitTorrent.

See the alternative downloads page for the links.


You will have to launch gconf-editor and navigate to Apps>metacity>general, then change mouse_button_modifier to <Super>.


KDE Plasma - Disabling all animations without disabling compositor altogether

Open System Settings > Workspace Behavior > Desktop Effects and disable individual effects with animations that you don't want. You will still have compositing active.

There is one more place to turn off some animations but this could be dependent on the theme. For example, with the defaults provided, open System Settings > Application Style and hover the mouse pointer over the style you're using. You may see a "pen" icon appear in the lower right corner of the style's box. Click on it. You may then see this:

Turning off style-provided animations


How do I remove an extension from LibreOffice 3?

You should remove an extension using the same way that you used to install it, i.e.:

If you downloaded it from the web, then the remove button should work.
If you installed it from the Software Centre, then it's installed system-wide (for all users) and you should remove it using the Software Centre.


Install mupdf-plugin/backend for `zathura` document viewer

The plugin is still not included in Debian repos and so I decided to package it myself.

I've uploaded zathura-pdf-mupdf package to Launchpad PPA ppa:spvkgn/zathura-mupdf, it contains packages for 16.04, 16.10, 17.04 and 17.10 Ubuntu series. The plugin compiled against library from latest MuPDF 1.11 version.

Please feel free to let me know if any issues with this package occurs.


Which Desktop Environments have a Window Overview feature like Mac OS's Expose?

compiz has an expose plugin (i think it's enabled by default, otherwise just activate it in compiz config settings manager). You can use it with any desktop environment you like (i use it with mate desktop for example).


How do I make brightness settings persist across rebooting?

If you're reducing the brightness using the buttons provided on the laptop, try this.

Open System Settings and go to Brightness & Power. Adjust the brightness and close the window. Hopefully, the settings would be saved.

Using `xbacklight`

There is an utility called xbacklight that lets you set the brightness of your screen.

Installing: sudo apt-get install xbacklight

Increasing/Decreasing the brightness: xbacklight -set X% where X is between 0 to 100.

You can add this in "Startup Applications" or add this command to /etc/rc.local.


installing Ubuntu 16.04 LTS server on dell server R720

Use rescue mode to get into the rootshell, then in the rootshell use following commands :

grub-install /dev/sda
grub-install --recheck /dev/sda
update-grub

reboot


Nope, not possible in the current version of Ubuntu. You might, however, want to take a look at / contribute to this thread on Ubuntu Brainstorm: http://brainstorm.ubuntu.com/idea/6030


Ok I found the issue. First one was what @muru pointed out second was using ' ' instead of " " in alias
and in file I have to not use it at all
So in alias correct
alias opentill="echo -en '\033p011' | lp -d EPSON_TM-T20III -o raw"
and for file
Desktop Entry]
Name=opentill
Exec=bash -c echo -en '\033p011' | lp -d EPSON_TM-T20III -o raw
Terminal=true
Type=Application
Thank you for poinitng me in the right direction


Webcam of Ubuntu 18.04 camera is on but there is opposite side appearence

Using the "nodrop=1" option from the command line worked for me:

cheese uvcvideo nodrop=1

If this doesn't work, then you can try enabling the same option in the uvc kernel module as follows:

Add the following to /etc/modprobe.d/uvcvideo.conf:

options uvcvideo nodrop=1

After you added that line, reload the module:

sudo rmmod uvcvideo && sudo modprobe uvcvideo

References:

https://bbs.archlinux.org/viewtopic.php?id=223106
https://help.ubuntu.com/community/UVC


You will need to set your DNS servers manually too.  Example:

vi /etc/resolv.conf

Add the lines (based on opendns):

nameserver 208.67.222.222
nameserver 208.67.220.220

restart your networking:

service networking restart

Double check your IP, Netmask and gateway.  They look ok on the surface but make sure nothing else on the network is using 192.168.1.100.

The section in your interfaces file should look similar to:

iface eth0 inet static
    address 192.168.1.100
    netmask 255.255.255.0
    gateway 192.168.1.1

More information here:
Set a static IP on Ubuntu

Dont forget to restart your networking after every change!


thinkpad_acpi.h missing from /usr/include/linux

Okay, for some reason the .h file re-appeared in newer kernel updates:

/usr/src/linux-headers-3.11.0-17/include/linux/thinkpad_acpi.h

The problem with missing header file was with 3.11.0-13 or 15, I can't remember exactly. Seems that the issue was later fixed.


How to make a dedicated Unity USB Stick

This is a way to make a USB key with
Ubuntu prereleases installed on it
that you can update every day and not
have to break your existing install.

Step 1: Download the latest Daily Natty image

Go to this page and download an ISO
for your computer. It should be saved
to the Downloads directory on your
computer.

Step 2: Create the USB stick installation

Click System -> Administration ->
Startup Disk Creator. It looks like
this:

When you start the application, it will likely automatically find the ISO you downloaded, which is displayed in the top pane. If you don’t see it, click the Other button and go and select the ISO (typically in your Downloads/ directory in your home directory).

It is recommended you first erase your USB stick, so select it in the bottom pane and click the Erase Disk button. When this is complete, you can then use the slider underneath the Stored in reserved extra space slider to select how much disk space can be used for saving files, documents and other things. Depending on the size of your USB move the slider all the way to the right to use the maximum space available.

Finally, click the Make Startup Disk button and Natty will be installed to your USB stick.

Step 3: Boot into the Key

Now you need to boot from USB stick.
To do this you may need to enter your
BIOS to enable your computer to be
able to boot from the USB stick. When
this is enabled you will typically
need to hit a button when you boot to
see the BIOS’s boot menu  and then you
can select the USB drive.

Ubuntu should boot and look and
function the same as usual, apart
from being much slower as you are
running from the USB disk.

Step 4: Update and Prepare the Key

Although you installed the latest
daily you should ensure it is up to
date, and you can do this with:

sudo apt-get update
sudo apt-get upgrade

From now on you can update the key
daily to keep it up to date. Now you
need to enable apport so that when
something crashes it can report it to
Launchpad:

Edit /etc/default/apport, set and set
enabled=1.

Step 5: Test and Report Bugs

If we don’t know about the bugs
our community can’t fix them!
Since the key can be updated you
merely need to update it before you
are ready to test and then try it on
as many pieces of hardware that you
can find. Since apport is set to
report crashers you can quickly start
finding hardware bugs.
Filing a bug
is simple. Just open a terminal and
run:

ubuntu-bug unity

The ubuntu-bug program zips up some
debugging data from your system and
will then fire up a page in your
browser where you can enter a bug
report. This will then provide
details of the problem to the Unity
developers to help fix the bug.

Ubuntu Liveusb Wiki


How do you update npm to the latest version?

I still don't understand why, but I have to run npm install -g npm twice for it to have the desired effect:

vagrant@box:~$ npm -v
1.3.10
vagrant@box:~$ sudo npm install -g npm
npm http GET https://registry.npmjs.org/npm
npm http 200 https://registry.npmjs.org/npm
npm http GET https://registry.npmjs.org/npm/-/npm-2.1.12.tgz
npm http 200 https://registry.npmjs.org/npm/-/npm-2.1.12.tgz
/usr/local/bin/npm -> /usr/local/lib/node_modules/npm/bin/npm-cli.js
npm@2.1.12 /usr/local/lib/node_modules/npm
vagrant@box:~$ npm -v
1.3.10
vagrant@box:~$ sudo npm install -g npm
/usr/bin/npm -> /usr/lib/node_modules/npm/bin/npm-cli.js
npm@2.1.12 /usr/lib/node_modules/npm
vagrant@box:~$ npm -v
2.1.12


How to install a package from the universe repository?

The package libweston-3-0 is from bionic (ubuntu 18.04) repository, and you're running artful (17.10), that is why you cant find it with apt.

Possible solutions:

Download package manually from bionic repo and try to install it (you may experience dependencies problems).
Download sources for libweston-3-0 and rebuild it for artful (long way).
Upgrate ubuntu to bionic.
Try to find ppa with libweston-3-0 for artful, note that it can have different name (you can use web search or search at https://launchpad.net/ ).


Get the first blocks of a torrent in priority

This functionality is not part of Transmission, is part of the Video Player. As I know, VLC and MPlayer can play of videos "corrupted" (in this case, video with only part downloaded), but also depends of the video format as some needs the header only and other needs the entire file.

Then, as BitTorrent and Transmission download the files in blocks and depending of the rarity, the only thing that you can do is try with one player and ignore if the popup a window saying that the file is corrupted, and if you're lucky with the type of file, you could see it.

Sources: https://forum.transmissionbt.com/viewtopic.php?t=13376&p=60672 https://superuser.com/questions/111405/how-to-preview-unfinished-torrent-video-files


Generally the problem here is that the dependencies steam requires are not being installed.  The command errors out because your system packages are in a bad state, you can see that in the full output from your second paste.

You'll need to run "sudo apt-get -f install" as suggested by the error output and hope that it can fix it.  In some cases, it might not be able to in which case you will need to seek further output with the exact output of that command.


How can I use Ubuntu live disk to get my data from a dead laptop hard drive?

From the live media, first try mount the drive in read-only mode.

sudo mkdir /mnt/tmp
sudo mount -tntfs-3g -oro /dev/sda1 /mnt/tmp

Then try to read anything you want from /mnt/tmp
The other, more dangerous approach is to try the mount with the (poorly documented) option remove_hiberfile, which will delete the entire last session.


How do I use my PC as a Public Address system

By running an Icecast server we are able to stream audio to either a local network or to the internet (see also project home page).

When running Darkice we can also stream any audio output of our local sound card live as an mp3 stream (with a minimum of 1s delay). The receiver side is OS independent but needs to be able to connect to an internet radio stream created by Icecast. Most audio players are capable to do so.


I took a read in the link you provided. They seem to forgot a space after -i in

pre-up wpa_supplicant -Bw -Dwext -ieth0 -c/etc/wpa_supplicant.conf

so it should be

pre-up wpa_supplicant -Bw -Dwext -i eth0 -c/etc/wpa_supplicant.conf.

Also, run ifconfig -a to confirm that eth0 is the wireless device, otherwise replace eth0 with the correct device.

If that still fails, check on your router to confirm that the server is connected and check if ssh is running by using sudo service ssh start


Uninstall Old Fedora OS and Install Ubuntu along side Win 7

First backup your important datas which was placed on that Fedora partition.
Now boot from the Ubuntu installation disk or live disk.
Click on Install Ubuntu option on startup and select something else option.
Now format the fedora partition into ext4 filesystem and then install Ubuntu on the formatted ext4 partition.
When the installer asks you to create a new swap partition then follow this to allocate how much space needed for the SWAP partition.


How to create iconpack for Kubuntu 16.04

Instruction on how to create KDE icon themes can be found here.

All creative credit goes to the original authors of the very good https://techbase.kde.org site, here is an exctract:

Icon Theme Usage

When developing software make sure to use the icons for the proper context of the widgets that you'll be placing in the application. Using icons from the wrong category in the wrong place will cause the application to look inconsistent and force 3rd party theme creators to use workarounds to theme applications.

Inside the icon theme folders the icon themes will have the following structure as described:

Theme_Name/
- The theme's name, pretty obvious.

Theme_Name/actions/

This folder is for icons that go in the toolbar, menus and buttons like: New ocument, Open, Save, Exit, Help, Settings, Back, Forward, Ok, Cancel, etc.

Theme_Name/applications/

This folder is for the software icons, their logos made into an icon. Icons in this folder should never be used for other purposes. Never.

Theme_Name/categories/

This folder is for icons that get displayed in menus like: Kickoff  Applications>Accessories, Games, Office, System), again, as the name implies to sort the categories. They are used to give categories an image as exemplified by Muon Discover. And like the above, Icons in this folder should never be used for other purposes. Never.

Theme_Name/devices/
This folder is for icons that are related to hardware a.k.a as devices, the icons here are used to display a device connected in certain places like Dolphin's left side pane, however they should not be used there nor in System Settings but in places like notification bubbles or the default places tab view in Homerun (full-screen). Icons in this folder should never be used for other purposes. Never.

Theme_Name/emblems/
This folder is for the icons that are displayed in the lower right corner of an icon in certain software to denote usually a characteristic of the file/folder, like permissions, ownership or to know whether its a link. Icons in this folder should never be used for other purposes. Never.

Theme_Name/mimetypes/

This folder is for icons that display the file type to every application. Icons in this folder should never be used for other purposes. Never.

Theme_Name/places/

This folder is strictly for user folders icons, folders like Home, Documents, Videos, or the regular folder icon go here, nothing else. Icons in this folder should never be used for other purposes. Never.

Theme_Name/status/

In Plasma this folder is not as important, as it only contains very few icons used in wvery few applications as the Plasma theme is what provides these icons, however for the sake of informing, here goes icons used in panels like the Mate DE panel, LXDE and XFCE panels and has icons like: Volume, Network, and the like. In Ubuntu-land these icons are known as Indicator icons.

index.theme

This file handles how the icons are displayed, at what size, and what's the path for each folder category.

Copyright notice


Install Ubuntu 14.04.1 LTS inside Windows 8

That option installs WUBI, which is no longer supported, should not be used, and is thoroughly incompatible with newer UEFI systems.

If you simply wish to try Ubuntu without risk to your existing Windows 8 install, use the 'Try Ubuntu' option instead of launching the installer. This will launch an Ubuntu session entirely in RAM; nothing will be installed to your hard drive.

If you have tried Ubuntu, and decided you want it, and if your hardware will support it, the safest way is to install a Virtual Machine application in Windows, and install an Ubuntu VM guest. Note that the VM depends upon the Windows host - a broken or compromised Windows install will break Ubuntu, too.

Alternately, you can modify your Windows install, shrink your partitions, and install Ubuntu and Windows side-by-side. Repartitioning a Windows system is risky - you might break your Windows install and lose your data. Make sure your data is fully backed up before starting. If you wish to repair or reinstall Windows someday, make sure you have your Windows Product Key written down, else you must purchase a new key from Microsoft.

Alternately, you can delete your entire Windows install and replace it with an Ubuntu system. This process will delete all data and applications. Windows applications do not work on Ubuntu at all, and --depending upon your skill level-- there may be a bit of culture shock. Before transitionin OS, change to multi-platform applications(like LibreOffice instead of MSOffice) to make the transition easier.


Well, Kubuntu is the slowest ubuntu-based distro.

If you want to make it faster, try to:

install e4rat (not recommended if you use an SSD);
Disable useless services. I may suggest you to disable network manager, the splash screen (How to disable Plymouth), wpa_supplicant, your display manager (KDM) - just use TTY;
Remove bloatware packages (packages you never use but are preinstalled)

... or just install Xubuntu / Lubuntu.


I/O errors when reading & writing downloads and uploads to NTFS drives

Windows has hybrid shutdown and then, Ubuntu can not wrtie to NTFS.
A real full shutdown of Windows allows the ntfs partitions to be mounted with R/W perms by Ubuntu.
For a full shutdown of windows, hold the SHIFT key as you press the "Shut down" button. You may also disable the 'fast startup' feature in the Windows power control panel.


Wifi speed is significently low compare to windows os in Ubuntu 14.04 LTS (RT3290 wifi wireless router)

This is well known bug with kernel drivers for this adapter.

You can vote there that the bug affects you too.

Or report another bug, since that one is marked as invalid.


Workspace is twice the size of my monitor

I found the answer:

Open the System Setting
In the hardware, open the display
You will see 2 “inside moniter”, you should click one to close.

Then the workspace will show one monitor.


Teamviewer on Jetson nano: CheckCPU: unknown architecture aarch64

FTR I found this first and then saw the comment saying you check it out:

unknown architecture 'aarch64'

  I was able to solve this by adding aarch64 to the checks performed by
  the start script. Navigate to where teamviewer is installed (for me
  this was /opt/teamviewer). Navigate further to tv_bin/script. Open
  tvw_main and find the section where it checks the architecture
  (CheckCPU function). Where you see ( armv71 ), add aarch64, so the
  line now reads ( armv71 | aarch64 ). Then try running it again (run
  "teamviewer" from the terminal).

The solution didn't work for two other users though..


Can apps installed by tar archive in home directory affect other system directories?

They can, but the consensus is that they should not.
Installation from tar.gz should be of 2 kinds of installations. an installer or install script that offers using ...

/opt/ as the installation path and then put everything except a symlink in /etc/ to the binary in /opt/ so a service gets started on boot. This one requires sudo and tends to be for larger projects (think jasperserver, a mysql from source) where more than 1 user use the software or where the software is a server.

/home/$USER/ and a subdirectory in there named after the software where everything gets installed there. This one does not require sudo and should not install anything outside of your home.
When you use this kind of installation and the installer asks for your sudo password this is a red flag. You need to stop and investigate. List the installer on screen and check why it is asking for it. Or ask on AskUbuntu ;)

I have yet to see software that did not follow this.
Only installers made for that specific OS (.DEB for Ubuntu/Debian, .RPM for Redhat etc.) should use the specific directories described in the Linux Filesystem Hierarchy.


You can use the open source implementation of wifi direct from the wpa_supplicant version 2.0.You can download it from http://hostap.epitest.fi/wpa_supplicant/ .Look at the the answer  How to get wifi direct( wifi p2p) on my HP DM1 laptop?.

I Hope that works fine.


Installing Teamspeak and creating TeamSpeak3 .desktop file

Ok you have some things wrong in your whole setup and like this it can not really work so I'm going through the whole installation process for you so you can pick up where you got astray.

download the TeamSpeak3-Client-linux_amd64-3.1.6.run from The Teamspeak Website
run the TeamSpeak3-Client-linux_amd64-3.1.6.run file with:

chmod 755 TeamSpeak3-Client-linux_amd64-3.1.6.run
./TeamSpeak3-Client-linux_amd64-3.1.6.run

move the whole new directory to /opt with

sudo mv TeamSpeak3-Client-linux_amd64 /opt/

change the ownership of the moved copy and recursively change the file permissions with:

sudo chown -Rv root:root /opt/TeamSpeak3-Client-linux_amd64
sudo chmod -Rv 755 /opt/TeamSpeak3-Client-linux_amd64

download some nice icon for Teamspeak, since the provided does not really look good, google simply for teamspeak ico png and download one and move it to the /opt/TeamSpeak3-Client-linux_amd64 and name it appropriately; I have chosen here simply teamspeak-icon.png
create your .desktop file in /usr/share/applications (you can copy and paste the whole code-block to the terminal):

sudo su &&
cat > /usr/share/applications/teamspeak.desktop << EOF
[Desktop Entry]
Name=TeamSpeak 3
Comment=TeamSpeak 3 VoIP Communicator
Exec=/opt/TeamSpeak3-Client-linux_amd64/ts3client_runscript.sh
Terminal=false
Type=Application
Categories=Network;Application;
Icon=/opt/TeamSpeak3-Client-linux_amd64/teamspeak-icon.png
EOF
exit

This should leave you with a working Teamspeak client working for every user on the system.


Wireless card does not detect any wireless networks

I have a Latitude-E6400 too. I solved it installing the b43 proprietary driver with these commands:

sudo apt-get install b43-fwcutter firmware-b43-installer

Then reboot and connect to a wireless network


How do I re-install Network Manager without an internet connection?

In case you only removed just Network Manager with the Software Center it is quite easy to reinstall by downloading only 2 packages from another machine connected to the internet:

Using packages.ubuntu.com, download the network-manager package from a software mirror close to you. Take care to choose the appropriate architecture (amd64 for 64-bit, i386 for 32-bit), and release version of your installed OS.
Download network-manager-gnome package likewise (am64 or i386).
copy both files on your spare USB pen drive and take it to the broken machine.
(e.g. network-manager-gnome_0.8xxx.deb and network-manager_0.8xxx.deb)
Install network-manager and network-manager-gnome simply by double-clicking on these two .deb files. This opens the Ubuntu Software Center or Gdebi for reinstallation.
After a reboot (or just logging out and logging back in) the network manager will run and uses your previous settings as before.

Note: This was not tested for the case when network-manager was removed in other ways, and if other applications were removed that may have deleted additional dependencies.


Xfce4 and Ubuntu 16.04 and recent firefox: get Emacs key bindings

On https://forum.xfce.org/viewtopic.php?id=8189 I found the crucial hint: Open xfce4-settings-editor, click on xsettings, click on Gtk and then either change the setting KeyThemeName to Emacs or create the setting KeyThemeName with the New button.

Worked for me without restart or logout/login.


Holding touchpad button detect multitouch

This worked on my Asus Q600a.

Remove and re-installing following two packages could solve your issue:

xserver-xorg-input-multitouch
xserver-xorg-input-synaptics

Follow these steps to remove completely and install it again.

Open terminal and execute following command:

sudo apt-get --purge remove xserver-xorg-input-multitouch

be sure you don't remove any other package than xserver-xorg-input-multitouch

sudo apt-get --purge remove xserver-xorg-input-synaptics

again follow the same precaution.

Once removed execute these commands to install it again:

sudo apt-get install xserver-xorg-input-multitouch
sudo apt-get install xserver-xorg-input-synaptics

again be sure you don't remove any other packages while installing it.

Once installed execute following commands to reconfigure it:

sudo dpkg-reconfigure $(dpkg -l | awk '{print $2}' | grep "^xserver" | tr '\n' ' ')
sudo update-initramfs -u

Then restart your system.

There is a GUI application for setting up your touchpad.  Mine shows in Dash as "Pointing Devices".  Gives you control of most of your touchpad features.

Go to the Software Center and search for "Pointing Devices" that will also be the name in Dash.


I'm a new user and Linux is a bit complicated yet to me. I think I found the solution
dir_mode=0777, file_mode=0777 in the /etc/fstab.

My problem is now solved. The problem was the permission in the fstab.


Can't find org.gnome.shell.recorder in gsettings

It's just because you're not running GNOME Shell, I guess that you're running Ubuntu Unity, not the GNOME variant.

To record screencast with sound, just install recordMyDesktop:

https://apps.ubuntu.com/cat/applications/gtk-recordmydesktop/


Can No longer Right-Click and Run MC.Jar (Minecraft) with Ubuntu 17.10

From your username, I'm going to assume you're trying to run a dedicated server, and will post my answer as such. This system has been battle-tested and is currently being used by a network where I am the infrastructure admin (alongside other fancy features), as well as countless other entry-level servers and production networks.

If you want a persistent auto-restarting server, you might look at creating a systemd service for your server. You will lose your GUI and headless interface, but you'll still be able to issue commands to your server through RCON or similar.

Effectively, you'd need to create a new user (let's call it mcserver) that will handle your server tasks:

sudo adduser --system --disabled-login --group --home /opt/mcserver

Next, you'll want to switch to this user:

sudo -u mcserver
cd /opt/mcserver

While you're here, copy all of your game server files and whatever over.

Next, create a new script to launch your server. Do not include any relaunch logic or similar. It should be very simple:

#!/bin/bash
/usr/bin/java -Xms1024M -Xmx4G -jar -XX:+UseConcMarkSweepGC -jar minecraft.jar --nojline --noconsole

Mark the file as executable using chmod +x mcserver.sh.

You can exit the session for mcserver, you won't need it anymore.

Create a new file (mcserver.service) in /etc/systemd/system:

sudo nano /etc/systemd/system/mcserver.sh

In this file, add the following contents:

[Unit]
Description=Vanilla Minecraft Server

Wants=network.target
After=network.target

[Service]
User=mcserver
Group=mcserver

ProtectHome=true
ProtectSystem=full
PrivateDevices=true
NoNewPrivileges=true
PrivateTmp=true
InaccessibleDirectories=/root /sys /srv -/opt /media -/lost+found
ReadWriteDirectories=/var/minecraft/server
WorkingDirectory=/var/minecraft/server

Restart=on-failure
RestartSecs=5

ExecStart=/opt/mcserver/mcserver.sh

[Install]
WantedBy=multi-user.target

Once you're done, you'll need to activate the service:

sudo systemctl daemon-reload
sudo systemctl enable mcserver.service
sudo systemctl start mcserver.service

The server will now auto-start on system boot, and run normally.

Note that the server will auto-restart on a failure (non-zero exit code), so /stop will stop the server without the chance for a respawn. While you may also stop the server with systemctl stop mcserver.service, it'll be unsafe as the server will not get to gracefully die. You can, however, use rcon to have the aforementioned command send a graceful stop. This, however, will be left as an exercise to the reader.

Backup scrips can still be run, though it would be advisable to use a user cron-entry that ZIPs the entire folder, and stores it somewhere safe.


How do I play mame games on 12.10 without being interrupted by the screensaver?

If you have installed Caffeine as fleamour suggested, it will do it automatically once you have configured it. This is done by opening Gnome Shell Extension Preferences ([Alt+F2]gnome-shell-extension-prefs[Enter]) and selecting  Caffeine in the drop-down menu.

You'll see a switch where you can choose not to display an icon in the top panel, and below that is an empty list. Press "Add Application" and add MAME to that list. It will then activate when you start MAME, and de-activate when you exit the program.

PS: You can also go to extensions.gnome.org in a browser, and get Caffeine and many other extensions there. (Direct to Caffeine: https://extensions.gnome.org/extension/517/caffeine/)


Conflicting dependency error when updating from Eclipse 3.7 to 3.7.1

not an Equinox user, but would suggest that the problem here might be related to the correct version of Equinox which works with 3.7.1 of Eclipse as a cursory examination of the release downloads from the Equinox downloads page is a bit confusing as to which version is the correct version to actually use with Eclipse 3.7.1.

Presume you would want to use a stable version, but the downloads section shows 3.7.x maintenance builds with odd release names (M2011....) and then 3.7 Stable builds with 3.8.x names, and then latest release builds with names more consistent with the current release numbers. This suggests that the problem is a dependency issue with the version loaded of the Equinox tools currently loaded into your version of Eclipse which are not compatible with the newer (updated) version of Eclipse.

This suggests that you may need to determine if the update to Eclipse requires a different version of Equinox, or if a reinstall of Equinox is required in order to update. You may wish to ask the Equinox community - not as familiar with this tool, but from what can be gathered, the version update will not resolve due to a dependency conflict which you can readily see. If Equinox can be removed and re-installed, that is probably the simplest method of updating.

HTH. Have a nice day. Wish there was more could advise, but Equinox is the issue, and not a regular user of same.


I had the same problem. When I tried to run update from terminal

sudo apt update

I got a message:

dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem.

After running the suggested command

sudo dpkg --configure -a

with default answers & reboot, the problem has been fixed.


fcaviggia/classification-banner, or its fork SecurityCentral/classification-banner that's been packaged for EPEL, work fine on Ubuntu. It is a Python application that is not made specifically for Fedora-based distributions. You can easily create a Debian package of classification-banner using stdeb.


Ctrl-C interrupts process, but doesn't clear terminal line

Turns out there was a mystery trap INT ... in my .zshrc. As soon as I removed that, Ctrl-C worked as expected again, clearing and returning.
I guess that this trap command swallowed my Ctrl-C, and therefore it didn't cancel the input!


Computer is randomly shutting down. What could be?

Maybe it's not the CPU overheating, but still the CPU. What you describe is exactly what I experienced a couple of weeks ago. I then ran memtest and everything, even plugged in a graphics card (as prior to boot the screen was messed up, sometimes instead of shutting down it simply froze). Finally I booted from several CDs to make sure it was not the installation messed up. Trying with a Linux Mint 12 CD lying around, it booted in text mode and there it was: The big error message which never made it into any log file, CPU0 being out of sync, kernel panic. So try booting from a CD and see what is displayed on the console (I didn't see that when booting from the hard disk into recovery mode of Ubuntu, but that may have been sheer accident).


Is steam available in Ubuntu Software Center?

Steam is still offered in the USC according to this in Saucy. Maybe you need to activate/add the proper repositories for the USC show it to you:

sudo add-apt-repository http://repo.steampowered.com/steam/ steam
sudo apt-get update


Err:6 https://ppa.launchpad.net/landscape/19.10/ubuntu bionic Release

PPA are accessible through clear http. Exception is for private-PPA which require authentication, but this isn't one of those. Also private PPAs are served from https://private-ppa.launchpad.net, thus likely explaining the SSL error you're getting.

I suggest to:

remove those https ppa entries
re-run sudo add-apt-repository --update ppa:landscape/19.10 so it can add back the ppa (as http, not https) and import the GPG signing key, if that hasn't been done.


Synaptic Error Message When Selecting "Reload"

Have a look at Software & Updates:

Dash >> Software & Updates >> Ubuntu Software >> Installable from CD-ROM/DVD

And 'un-check' your rogue entry for the 15.10 CD-ROM. Screenshot to show the location:

If this does not fully resolve the issue check through the other tabs that you can see in the screenshot above ('Other Software' and others) and weed out any references to versions of Ubuntu other than 16.04.

Then allow the Repositories to reload...


Is it sure that your Wireless / Router device is working well?  If your IP is automatic and Wireless Router device works well then:
1) Give reset to your device (hardware one and reconfigure it again from the beginning)
2) Click your network icon >> Disconnect wired and wireless connections on your pc
3) Right click your network icon >> Edit Connections...

on Tab [ Wired ] click on connection and then on right side click on button Delete.
on Tab [ Wireless ] right click on connection and then on right side click on button Delete.
(Delete all connections and turn off your router).

Restart your PC!
Let your device off, and after your system is on, switch off your wireless key, turn on your device and connect your wire cable. A new connection is going to be created automatically. Now test it going online. If it is OK then restart your PC and disconnect wire cable and switch on wireless key of your notebook. After detect your wireless connection, click on network icon, click on your connection and test your notebook by going online. ( I guess this is going to solve your problem ).

Anyway, you may control if your system is well configured by booting your notebook with Ubuntu live CD and connect to the wireless. Stay connected and if it is OK than the problem is at your system configuration.


How to install dash to panel on Ubuntu 17.10

The easiest way to install and activate Dash to Panel is from extensions.gnome.org. Open Firefox or Chrome and go to Dash to Panel's homepage. Click on the the toggle button at the top right to turn it ON.

NOTE: When you visit extensions.gnome.org for the first time it should ask you to install one browser add-on/extension. You'll have to install that extension to make this toggle button appear.

NOTE2: You might need to install the 'Gnome shell host connector". You do that via apt.

sudo apt install chrome-gnome-shell

It doesn't matter if you do this before or after the prompt.


Why does my upgrade says it needs more space than what a clean installation needs?

This is because the installer needs to download the updates packages first, which pretty much sums 3 times what you are using right now. Example:

You have 3 GB of programs installed, the packages to upgrade all that weights about 1.7 GB, now all those packages need to be uncompressed when installing, so you will be using 3 GB or more extra. The grand total 7.7 GB of data to do a full upgrade. That's why you need the extra space when upgrading from a release to another. In your case, since you have already /home in another partition, just install Ubuntu 12.04 on top of the root filesystem. Tell the installer that you want to use the old /home without formating, and you should be in 12.04 pretty quick.


The procedure for reinstalling is basically the same as the first install, just make sure you format the root partition for a clean install. You can look at this tutorial (http://www.dedoimedo.com/computers/dual-boot-windows-8-ubuntu.html) for reference.


1. Kill all sshfs processes

Either with killall command:

killall sshfs

or selectively:
Find all running sshfs processes:

ps -ef | grep sshfs | grep -v grep

Say you've got two of them running:

$ ps -ef | grep sshfs | grep -v grep
root     10906  5170  0 07:14 pts/0    00:00:00 sudo sshfs
root     10907 10906  0 07:14 pts/0    00:00:00 sshfs

Now kill them both or selectively by identifying them by their PID:

sudo kill -9 10906 10907

2. Unmount your mount point

sudo umount -l /mnt

3. Edit /etc/fuse.conf so you never meet the fuse: bad mount point `/mnt': Transport endpoint is not connected error again:

Open it as root with your favorite editor, for example

sudo atom /etc/fuse.conf

Uncomment the user_allow_other line.
Save and close.

4. Use SSHFS with the following options:

sudo sshfs \
-d \
-o allow_other \
-o reconnect \
-o ServerAliveInterval=15 \
user@domain.com:/ /mnt \
-p 12345 \
-C

-d turns debug mode on (gives more output)
-o stands for "option"
-p allows you to specify port number
-C turns on compression

Sources:

https://www.unix.com/unix-for-dummies-questions-and-answers/2470-correct-use-ps-ef-grep.html
http://slopjong.de/2013/04/26/sshfs-transport-endpoint-is-not-connected
https://unix.stackexchange.com/questions/184965/open-file-from-remote-computer-on-host-computer


How to install/uninstall a driver on a frozen system using a liveCD

Try to boot on recovery mode. To get the grub menu to show up, just short-press the SHIFT key several times after your bios POST messages (you might be able to see the Loading GRUB... message, that's the moment.

Then, choose the option netroot on the recovery menu, and remount your filesystem with write permissions by using this command:

mount -o remount,rw /

Then, follow the instructions on the Unnofficial AMD Catalyst wiki for 12.04 or for 12.10.

If you don't have Internet access (you don't have direct ethernet access with dhcp, need wifi, etc.) you can't do this, but just do the first step and you should be able to boot your system again. After boot the system and get Internet access, do the other steps.

And when you are done, just reboot:

reboot

Can't you make into the grub menu?

Just let's do it from a live cd environment. Just ensure the live cd is for the same architecture as the installed system. Open up a terminal. Then, mount your / partition.

sudo su
mount /dev/sda1 /mnt

That is, assuming your / partition is on /dev/sda1, of course, which might not be the case. Try to guess the correct device by using the Disks tool.

Then, create a good environment, and use chroot:

mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc
mount --bind /sys /mnt/sys
mount --bind /run /mnt/run
chroot /mnt

If everything is OK, now you are inside your installed system, running inside a chrooted environment. From here, follow the wiki instructions.

When you're over, hit Ctrl+D to exit the chroot environment. then, carefully umount your system, and reboot

umount /mnt/dev /mnt/sys /mnt/proc /mnt/run /mnt
reboot


Try to see if the sound is muted whenever you have headphones or external speakers connected to computer. I had the problem that if I had headphones connected or speakers then the embedded speaker would not work. This problem is best known as "speakers will not mute"


Looking for a way to list video length in nautilus list view column

You can install this package to get more column options:

sudo apt-add-repository ppa:nilarimogard/webupd8
sudo apt-get update
sudo apt-get install nautilus-columns

The attribute you are looking for is Length.


Kubuntu/Macbook: Monitor not detected. Mini display port to vga adapter

I just downloaded the latest kernel Release Candidate and did a grep --recursive --ignore-case Moelissa and the results are: zilch, nada, nothing, rien du tout, nichts, nikske, ничего, नथिंग!

So you basically have 3 options (higher number is more difficult):

Do nothing and wait until Linus Torvalds gets to your problem.
Buy one that has Linux support
Get involved in Linux kernel development and develop a driver yourself


For the most part if anyone has physical access to the machine security is null and void. As for "other users" if they are not trying to access the files and might just stumble into it just set the permissions on your home folder so no one else has any access except you.

As far as security over a network I find it hard to believe someone would get into your personal files unless you carelessly leave ports open. If you are concerned use Gufw to manage your firewall. You can also check from this website if you have security holes of some kind: https://www.grc.com/x/ne.dll?bh0bkyd2

Also you can read this security overview on the Ubuntu forums: http://ubuntuforums.org/showthread.php?t=510812

I hope this can be of help to you!


To get rid of such problem simply download super-boot-manager.

You will need to add the ppa:ingalex/super-boot-manager before. Open a terminal.

sudo add-apt-repository ppa:ingalex/super-boot-manager
sudo apt-get update
sudo apt-get install super-boot-manager

Once installed run the program, and select "Grub-manager", go under "Parameters", "Param. 1" and select the default OS to boot from.


How to change the application switcher on Ubuntu 18.04 and 17.10?

On Ubuntu 17.10 and Ubuntu 18.04 with the Gnome Shell desktop, which uses mutter rather than compiz for managing windows, you can use different application switchers by installing appropriate extensions. Alternatetab is an officially supported extension that provides you with a document based switcher, rather than the default application based switcher. Coverflow Alt-Tab allows switching windows in a cover-flow manner. These extensions can be installed from Gnome extensions.


This is not a bug. If we don't store your credentials somewhere, then we would have to ask you for your Ubuntu One password on every login.

If we store the credentials in a safe place, like we do now with the Keyring, then the Keyring will ask you for its password when you login.

The only "solutions" for this are:

1) You make the keyring less secure and it doesn't ask for a password on login.
2) Ubuntu One stores the credentials insecurely (outside of the keyring) like some other
   applications do.

Both are a security risk, since anyone with physical access to your device can grab your credentials.

In my opinion, what we have now is as good a solution as it's possible to have.


Installing v. 12.04.2 graphics card not recognized chrome9

I installed the missing dependencies with:

sudo apt-get install xorg-video-abi-11

And rebooted.

Everything works now.


14.04LTS Unity Desktop on my main account not functioning

What worked was to remove the following file for that user account

rm ~/.config/dconf/user

This put back the launcher and the menu bar in that account.
I still got a system error report pop up, (the same had popped up once earlier but was unfathomable to me at the time).   In the details was some complaint about libprocps3, so I reinstalled:

sudo apt-get install libprocps3-dev

as advised in this help page


You did it wrong.

The correct desktop file Subline_Text_Editor.desktop should contain only last lines:

[Desktop Entry]
Exec=/usr/bin/stext
Version=1.0
Type=Application
Icon=/home/pc/Downloads/sublime_text_3/Icon/256x256/sublime-text.png
Name=Sublime Text Editor
Terminal=false
Categories=Application

There is no need to have header line (#!usr/bin/env xdg-open in your case).

You do not need sudo to make it executable.


[  175.182426] vboxdrv: module verification failed: signature and/or required key missing - tainting kernel

I am not sure if this is causing your problem, but there seems to be a problem with the signature of vboxdrv, see here:
https://stackoverflow.com/questions/24975377/kvm-module-verification-failed-signature-and-or-required-key-missing-taintin
Does your virtualbox have a custom setup?
Perhaps reinstalling virtualbox would do the job


Ubuntu overheats after starting from hibernation, but not after restarting

Ubuntu 14.04 uses kernel 3.13 and since 3.13 there is a major bug in controlling the fans!

I saw reports about affected HP and DELL laptops, and even Macbook Air. The symptom on my HP Compaq nx8220 is that the fan speed is set according to the temperature, but only once at boot time or when resumed after suspend! At boot time the temp is usually medium and the fan stays at medium speed. But after resume the temp is low, the fan stays off and the system overheats easily.

I was able to fix it today (July 13 2014) with a pre-release of kernel 3.13.0-32 from https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa

Careful users should wait a few days to get this fixed kernel as a normal update!

From what I have read the problem was a kernel patch called "ACPI / AC: convert ACPI ac driver to platform bus" which has now been reverted in kernel 3.13.0-31 and higher.


Theoretically, you can format your 3TB disk to work with your old motherboard with BIOS via partitioning it with a GPT partition table rather than MSDOS. However, it's not totally foolproof. Some BIOSes attempt to validate partition tables when they should not and that can cause problems because of the "protective MBR" that a GPT-partitioned disk uses.

Do note that not all Linux disk tools work with GPT-partitioned disks. You would need to use gdisk rather than fdisk for example. The graphical Gparted and command line parted should have no problems with this.

So, really, there's no definite answer to this. However, all UEFI motherboards should be exempt from this problem.

If you're going to be dual-booting, you need to be sure that your new Windows OS has support for GPT partition tables (see EDIT 1). Windows will only install to a GPT if a) the OS supports booting from GPT (see below table), and b) you are using a UEFI firmware, so dual-booting using a pure GPT disk not supported -- of course you could always make a hybrid MBR.

EDIT 1: GPT features of Windows versions are kind of mixed.

Windows 95/98/2000/NT 4: Lol! Not a chance.
Windows XP 32-bit: No support
Windows XP 64-bit: Data disks only (no boot capability)
Windows Server 2003 SP1+: Data disks, booting only on 64-bit IA-32/Itanium systems.
Windows Vista/7/Server 2008: Data disks, booting only available on UEFI-based systems

Source: MSDN


If you no longer need to maintain the sync i.e. all your contacts are now in UbuntuOne you can disable sync and then simply delete all the notes from inside Evolution. This will eliminate the need to keep the single characters in the notes section.

Once this is done your updated Evolution files will take priority over your web  based copies and the notes from FB will never return.

I believe it has something to do with the way the notes from  Facebook sync with Ubuntu in the sense that you are not taking contact information only their picture, name and anything they have added to notes.

Hopefully FB and Ubuntu will do some kind of deal to allow the publishing of email addresses in the sync.


As it has been stated already sudo it's not needed (neither to run commands in rc.local in general, nor for running xgamma specifically) but the problem here it's xgamma requires (of course) the X server to be running, but rc.local it's executed (as it's stated within rc.local's comments) at the end of each multiuser runlevel, which is way before the X server is started.

To run the command right after the X server has been started create a script named .xinitrc in ~ (touch ~/.xinitrc), mark it as executable with chmod +x ~/.xinitrc and put the command there:

#!/bin/sh -e

xgamma -gamma .8
exit 0


Try to run dhclient eth0 (It will get you an IP address from the router: if it is configured to do so).

If that method works go to network connections; select your wired connection and click edit; go to IPv4 settings tab; change the method to Automatic (DHCP).

Or you can simply add the following lines to /etc/network/interfaces

auto eth0
iface eth0 inet dhcp


is there a way to move launcher to the right side of screen in 14.04?

You can't move the dock in 14.04. While there are some unofficial plugins that make this possible (that have since seemed to vanish), it wasn't a native feature.

That feature was added in Ubuntu 16.04, which only supports moving to the bottom. The command to make this take effect is below:

gsettings set com.canonical.Unity.Launcher launcher-position Bottom


Use opendns.com and opendns DNS servers...

208.67.222.222

208.67.220.220

Then you can use your "OpenDNS dashboard" to get (showing clips) reports like this:

and this:


The easiest way to launch a command when a user logs in is to create a .desktop file for the command and stick it in the ~/.config/autostart folder. What does the desktop file look like? Here is an example that retrieves the Ask Ubuntu home page with wget every time the user logs in:

[Desktop Entry]
Name=Launch wget
Comment=Fetches the Ask Ubuntu home page.
Exec=wget http://askubuntu.com/


ssh: connect to host xxxx@xxxx.in in port 22 : connection timed out

Try to check if port 22 is listening:

sudo netstat -alnp|grep :22

Try to allow port in ufw

sudo ufw allow 22

sudo ufw disable && sudo ufw enable

Try to add port into iptables

sudo iptables -A INPUT -i eth1 -p tcp --dport 22 -j ACCEPT

Is port forwarded?


`do-release-upgrade` still trying to use archives instead of old-releases

The configuration files for the update manager must also be updated!

If upgrading from an unsupported version of Ubuntu like I was, change the repositories in /var/lib/update-manager/meta-release to point to the old-releases repositories.  E.g. for upgrade from 15.10,

make sure you have successfully run sudo apt-get update and sudo apt-get upgrade with appropriate repositories in /etc/apt/sources.list
find Dist: wily inside meta-release (substitute "wily" with your version name if updating from other unsupported release)
replace http://archive.ubuntu.com/... with http://old-releases.ubuntu.com/... each time it appears in the block corresponding to the release
now run sudo do-release-upgrade

A similar question was asked here -- though no official answer is given.  The question is marked as a duplicate, but neither it nor the questions it links to answer this issue of modifying the update-manager configuration.


Package ipython is not available I am using ubuntu 20.04.2LTS

If you install it from the GitHub it should work with 20.04.
Go to https://github.com/ipython/ipython/releases and download the Source Code (tar.gz) file.
Extract the contents:
tar zxvf ipython-7.18.1.tar.gz

Enter the newly created directory:
cd ipython-7.18.1/

Then use pip3 to install it:
pip3 install .

Don't forget to add the . at the end of the command meaning to install from here.
Hope this helps!


Suggestions for rolling out a WebServer and Load Balancer with Juju Charms

Your best bet may be to try on a public cloud or in a local (lxc) environment to get a feel for how deploying and relating charms works. You can find the documentation on how to get started here: https://jujucharms.com/docs/#introduction

Once you have that set up you can try deploying the following:

juju deploy ghost
juju deploy haproxy
juju deploy mysql
juju add-relation ghost haproxy
juju add-relation ghost mysql

This environment is outlined in detail here: http://fromanegg.com/post/97035773367/juju-explain-it-to-me-like-im-5 which seems to follow similar a similar structure to what you want your environment to look like.


How to know whether Xubuntu is running on ram or the live USB?

RAM or Not to RAM
I understand that even if Ubuntu is not booted toram that it still runs mostly in RAM. It seems to somewhat depend on how the Live/Persistent drive was created.
If you boot normally, and open several programs, say GParted and LibreOffice Writer, then close the programs and unplug the USB, the programs should still be in memory and can be restarted without the USB. (This did not work for me with mkusb Persistent last time I tried).
Programs that were not previously booted, will not boot with the USB unplugged.
If you Boot toram and unplug the USB, (after everything stabilizes), all the programs, (within filesystem.squashfs), should be bootable.
My recommendation is to wait until you are sure the USB is not being written to, yank the USB and try starting a program that you have not just been using, say Calculator or Solitaire. If it starts you are likely booted toram.
If you do not like the idea of yanking your USB you should be able to unmount it using: sudo umount -lrf /cdrom where is the path to the root partition.
After you shut down a Live install that has been running in RAM, (such as an Etcher ISO9660 clone or Ventoy ISO file boot), all data in RAM disappears, as long as hibernation has not been set up on the disk. If hibernation has been set up, RAM data gets dropped into a swap file or partition and is available on resume. It is not easy to set up hibernation on a USB that does not have persistence or a Full install.


Ubuntu 14.04: LXD PPA no longer available

LXD is a container manager for system containers.

To install LXD in all currently supported versions of Ubuntu open the terminal and type:

sudo apt install snapd
sudo snap install lxd

LXD is a container manager for system containers. It offers a REST API to remotely manage containers over the network, using an image-based workflow and with support for live migration. Images are available for all Ubuntu releases and architectures as well as for a wide number of other Linux distributions.

LXD containers are lightweight, secure by default and a great alternative to virtual machines.


Permission difference between root root and www-data root

In Linux and Unix, everything is a file. Directories are files, files are files and devices are files. Devices are usually referred to as a node; however, they are still files. All of the files on a system have permissions that allow or prevent others from viewing, modifying or executing.

In first one

 -rw-r--r--

the permissions are as follows for user, group and others

owner = Read & Write (rw-)
group = Read (r--)
other = Read (r--)

while in second one

-rw-------

only user have read, write permission,i.e

owner = Read & Write (rw-)
group = None (---)
other = None (---)

For more details read File Permissions Here


VNC client(only) in Ubuntu 18.04 headless server

you can install only libvirt-daemon-system on the server which will not pull in any UI components.

I'd assume you already have a SSH key based setup to reach your server, if not I'd set one up before the next step.

On the client install virt-manager - if you want even without recommends (as you don't want to virtualize on the client).

You now can connect the libvirt on the server as a remote via the menu "File -> Add Connection".

You can now either use virt-manager to install from an ISO, or use any other commandline tool on the server to create your initial guest. Later on you can start/stop/view that remote guest from virt-manager as needed.

I quickly checked, and while a bit dated this doc seems to cover the basics still.


Access Windows Partition with Read and Write Access from Ubuntu 18

There are two reasons that I can think of why you can't use your Windows partition. Windows often has an issue with hanging on to the partition if it is not shut down completely. Holding down the shift key while shutting down Windows should fix this problem. If you don't want to completely turn off your computer to boot into Windows to completely shut it down and reboot again, I'd check out this answer here.

However, since you are able to read it, this sounds more like a problem with permissions.
Go ahead and check out this article to find out how to mount your NTFS Windows partition to enable permissions. I'd also suggest checking out some of the other links that other users have been suggesting under your comments.

Then, open up your terminal and type up sudo nautilus and then left click on your Windows partition once the file manager pops up. Select Properties and then navigate to the Permissions tab. Then change the Owner and/or Group to your username. Then hit the Change Permissions for Enclosed Files... button on the bottom of the properties window. Then change the Files and Folders permissions to Read and Write for the Owner or Group, whatever you changed earlier.

You can also do the same thing all in the terminal with chown and chmod but that's another answer.


All the future files that you save in your home directory will be encrypted as well.


How to add package source to ubuntu package list

There are a number of paths that a package can take to enter Ubuntu. In most cases, going through Debian first can be the best path. This way ensures that your package will reach the largest number of users as it will be available in not just Debian and Ubuntu but all of their derivatives as well.

Here are some useful links for submitting new packages to Debian:

Debian Mentors FAQ - debian-mentors is for the mentoring of new and prospective Debian Developers. It is where you can find a sponsor to upload your package to the archive.
Work-Needing and Prospective Packages - Information on how to file “Intent to Package” and “Request for Package” bugs as well as list of open ITPs and RFPs.
Debian Developer’s Reference, 5.1. New packages - The entire document is invaluable for both Ubuntu and Debian packagers. This section documents processes for submitting new packages.

Source: http://packaging.ubuntu.com/html/packaging-new-software.html


Bluetooth is neither scanning devices nor visible in 18.04

You have an error

bluetooth hci0: Direct firmware load for brcm/BCM43142A0-0489-e062.hcd failed with error -2

You should install drivers suitable for your bluetooth interface


The zero-fill method (here modified to avoid potential memory bottlenecks) took 17 seconds to create a 10 GB file on an SSD and caused Ubuntu's graphical interface to become unresponsive.

$ time sh -c 'dd if=/dev/zero iflag=count_bytes count=10G bs=1M of=large; sync'
10240+0 records in
10240+0 records out
10737418240 bytes (11 GB, 10 GiB) copied, 17.2003 s, 624 MB/s

real    0m17.642s
user    0m0.008s
sys     0m9.404s
$ du -B 1 --apparent-size large
10737418240     large
$ du -B 1 large
10737422336     large

fallocate creates large files instantly by directly manipulating the file's allocated disk space:

$ time sh -c 'fallocate -l 10G large; sync'

real    0m0.038s
user    0m0.000s
sys     0m0.016s
$ du -B 1 --apparent-size large
10737418240     large
$ du -B 1 large
10737422336     large

truncate also works instantly, and creates sparse files which don't use up actual disk space until data is written later on:

$ time sh -c 'truncate -s 10G large; sync'

real    0m0.014s
user    0m0.000s
sys     0m0.004s
$ du -B 1 --apparent-size large
10737418240     large
$ du -B 1 large
0       large


Ubuntu Touch change system settings from command line (silent mode specifically)?

It seems to work (with OTA-11, connect with SSH):

amixer -q -D pulse sset Master toggle

Edit: From https://askubuntu.com/a/444183


Creating script to cp directory multiple times

{2..5} is brace expansion. Brace expansion is not standardized by POSIX. Some, but not all, of the widely used Bourne-style shells support it.
The shell you interact with in a terminal on Ubuntu is bash, unless you're deliberately using a different one. bash supports brace expansion. But the shebang on your script is for sh, which on Ubuntu is a symlink to dash. dash does not support brace expansion.
So you can either:

Make your script a bash script (or a script for some other shell that supports brace expansion, such as zsh or ksh).
Replace brace expansion in your script with something that works in dash.

If you want to make your script a bash script, replace
#!/bin/sh

with:
#!/bin/bash

Then when run like ./scriptname it will be run in bash. If you're running your script by writing sh scriptname then you must use bash scriptname instead.

If you want to eliminate brace expansion, there are a few alternatives.  I suggest seq with command substitution, which is probably the most common alternative to brace expansion, is easy to write, and is likely to be understood by other human readers.
In place of {2..5}, you can write $(seq 2 5). Since it is not quoted--that is, since it is $( ) and not "$( )"--field splitting (which in bash is called word splitting) is performed on the result. So long as you have not set the IFS shell variable, which controls field splitting, to a value that contains any digit or that does not contain a newline, this will do what you want.
(Globbing--also called filename expansion, also called pathname expansion--is also performed on the result of unquoted command substitution, but the output of seq will not contain the globbing characters ?, *, or [, so that has no effect in this case.)
Note that seq is not standardized by POSIX. This will work on just about any GNU/Linux system and some other Unix-like operating systems, but some Unix-like OSes don't have seq installed by default (they usually have jot instead) so it is not guaranteed to work on all Unix-like operating systems.


How can I extract the deb files from the ubuntu iso?

Most of the debs Ubuntu uses are installed into a chroot before generating the ISO image, so you can't just get them back. If you unsquash the filesystem, you'll see it looks like just a root filesystem. For example, this is a truncated view of ls:

drwxr-xr-x   2 root root  4096 Oct 12 16:59 bin
drwxr-xr-x   3 root root  4096 Oct 12 16:59 boot
drwxr-xr-x   4 root root  4096 Oct 12 16:56 dev
drwxr-xr-x 134 root root 12288 Oct 12 16:59 etc
drwxr-xr-x   2 root root  4096 Oct  9 08:59 home

...

If you want to mess with the chroot, you can do so as follows:

Mount the ISO

sudo mount -o loop quantal-desktop-i386.iso tmpiso

Copy the squashfs out

cp tmpiso/q/casper/filesystem.squashfs /tmp

Unsquash the filesystem

sudo unsquashfs filesystem.squashfs

This will unpack the filesystem into squashfs-root.
Make your changes.
Recompress with squashfs.
Use ISO master to replace the filesystem.squashfs with the one you modified.
Rebuild the ISO with ISO master.


How do I add an EFI partition to a fresh PC?

You don't need to create a EFI partition. If you booted the LiveUSB in UEFI mode and select to Install Ubuntu, the partition will be created automatically.
You can also chose "something else" and create all partitions you need including EFI manually.


Ubuntu 15.10 freeze seconds after startup

I managed to solve my problem.  It required something a little different than @cl-netbox described on this post, though I did try the described sequence (including adding noveau-modeset=0 to the first line after pressing E on the Try Ubuntu without installing option).  When the Unity desktop had loaded, and before it froze, I pressed Ctrl + Alt + F1. The nvidia-355 driver would not install, neither did the 361.28 driver that the nvidia website suggested was appropriate for the GTX970 graphics card on Linux-64.

I ran the command sudo ubuntu-drivers devices and noticed that the installed driver was 352. I then ran sudo ubuntu-drivers autoinstall.  I repeated sudo ubuntu-drivers devices and noted that the installed driver was still 352.  Then I rebooted, and was treated to a fully functioning Unity desktop.  So far no freezes or other issues.

I assume that the autoinstall fixed something, somewhere.  I can appreciate that different hardware and installations require different solutions.  Apologies I could not regurgitate the full terminal outputs, but perhaps this will help someone with a quick fix.


Blurry screen on VGA with Ubuntu 18.04 LTS

I have found solution: use proper VGA cable. For whole time I was using VGA cable that came with my cheap projector. When I have borrowed VGA cable from coworker the issue was gone.


how to add chinese input on ubuntu 16.04

You can consider to use gcin, it's easily installed.

sudo apt-get install gcin
im-config # this will show a windows, just select ok and then yes

After the im-config command, a window will pop out. Just select gcin, press ok, then login and logout. Now you should see a new icon on the upper right of your screen and be able to use Chinese input by pressing <ctrl> + <space>


Using PPA-Purge

sudo apt-get update
sudo apt-get install ppa-purge
sudo ppa-purge ppa:venerix/blug
sudo apt-get update

Manual Uninstall

Type the following in this order into your terminal:

sudo apt-get update

--> updates the apt-get database

sudo apt-get remove --purge tv-maxe

--> removes the package tv-maxe including config files

sudo apt-get autoremove --purge

--> removes leftover packages that were installed as dependecies including config files

sudo add-apt-repository --remove ppa:venerix/blug

--> removes the software repository from the software.sources list

sudo apt-get update

--> updates the apt-get database

With both methods there might still be some configuration files left in your home directory. In order to remove them you will have to head to your home directory, hit Ctrl + H to display hidden files and search for any entries related to tv-maxe.

Edit: As gertvdijk has pointed out, ppa-purge is the better option here because of the external PPA.


First its GNUstep not GNUsetup , some one downloaded or installed it on your desktop .

GNUstep provides an environment to easily develop advanced GUI desktop applications as well as server applications.

GNUstep offers Development tools for command-line and GUI development, as well as the foundations for a Desktop environment, which other projects can complete.

Reference


no space left and weird output of df -kh

You've installed on a FAT32 partition most likely - which has a single file size limit of 4GB. So Wubi splits the install into separate virtual disks of 4GB. You have one for /, /home and /usr

One of these (/) is running out of space (root.disk). There's no way to fix this really - maybe you can clean out your package cache (sudo apt-get clean).

It's better to install Wubi on an NTFS partition as then you'll get a single 14GB (or up to 30GB) virtual disk and so you won't have this problem. Or if your FAT32 partition is just for Ubuntu (which it appears it is), then install direct to it (not with Wubi).


Ubuntu installer doesn't see that Windows is already installed

Maybe the disk has a GPT partition, this also happens when the user has Windows 8 with secure boot (UEFI) enabled. I faced that, and I did this

1- First, make sure that you don't have secure boot/UEFI enabled, you can check it in the bios

2- Boot ubuntu from USB

3- Open the disks utility

4- Delete all existing partitions of the desired disk, and press CTRL+F

5- Select MBR/DOS from the partitioning type, and then format

6- Make a ntfs partition using the whole drive

7- Shutdown Ubuntu and boot to the Windows 7 installer

8- When you're going to install, click on advanced/custom install (so you can edit
partitions)

9- Select the ntfs partition that you created with ubuntu. DON'T delete that partition, install over it

10- After installing Windows 7, try to install ubuntu and see if the installer detects Windows 7.

I did that and after I was able to install Windows 7 and Ubuntu. You need to create a ntfs/mbr partition with ubuntu, because if you install Windows it will use GPT and as far I know ubuntu isn't very good when trying to get a dual boot when the disk has a GPT partition table.

Hope it help you. Cheers


Unable to install net-snmp of ubuntu 16.04 : error received

/usr/bin/ld: cannot find -lperl

This is the linker, complaining that it can't find perl libraries.
To install the perl libraries, run sudo apt install libperl-devel.
But as you do not have internet connectivity, this is probably not possible. You can download the package from here, but it must match other installed perl packages - which in a offline system requires some tracking down.
You write that you have the machine in a DMZ. You should configure some way for the machine to reach internet, to get updates and install software. This can be via an apt proxy, which will behave like a local mirror, without the overhead to mirror all packages that you don't need.
Running machines without access to updates is considered a security risk - and as you've discovered, makes installing software more difficult.


How to close all instances of a program instantly?

From command line:

killall file-roller

You can do alt+f4 but you need to do that for every archive manager that was  opened.


There is a new version of Moscow ML, 2.10. It is available here: Moscow ML

I have also taken the liberty of creating a mosml package in my launchpad PPA. To install it, issue the following commands:

sudo apt-add-repository ppa:pmunksgaard/mosml
sudo apt-get update
sudo apt-get install mosml

It should work on both 32 and 64 bit systems.


grub not showing when installed on a separate boot partition

Try this:

Boot from an Ubuntu Live CD and go to terminal by pressing Ctrl+Alt+T.
Install GRUB specifying the boot partition like this:

sudo mount /dev/sdaN /mnt

sudo grub-install –boot-directory=/mnt/boot /dev/sda

assuming /dev/sda is your primary drive and N is the /boot partition number.

If it does not work try the boot-repair method listed elsewhere.

Hope this helps


Well, that is kind of obvious that there is no free space left or right of your partition. So where do you want to increase its size ?

Your only viable solution is to copy your sda6 partition into the unallocated space of 39GB then once this is done, increase its size to 39GB.
And finally, delete the original sda6 partition.


18.04.5 -> 20.04.1: grub2 configuration failure

I experienced the same problem, and, at least for me, it seems I have solved it.
The problem seems to be caused by a replacement of my hard drive many years ago.
Thus the entry for grub-pc/install_devices in /var/cache/debconf/config.dat
was invalid or missing, and so grub-pc.postinst tried to ask for it.
Unfortunately grub-pc.postinst ran in non-interactive mode; this might be
the main problem.
Actually, I solved the problem with a temporary patch to grub-pc.postinst,
which simply set the grub-pc/install_devices variable to my new hard drive id.
But probably it should be enough to edit /var/cache/debconf/config.dat directly.
Of course, this is not a general solution, since I hardcoded the device id.
My patch:
--- grub-pc.postinst    2020-10-11 12:50:47.288340305 +0200
+++ /tmp/grub-pc.postinst   2020-10-11 12:47:05.433847886 +0200
@@ -549,6 +549,7 @@
           priority=high
           device_map="$(grub-mkdevicemap -m - | grep -v '^(fd[0-9]\+)' || true)"
           devices="$(echo "$device_map" | cut -f2)"
+          db_set grub-pc/install_devices "/dev/disk/by-id/ata-Samsung_SSD_850_EVO_mSATA_1TB_S246NWAG406372X"
           db_get grub-pc/install_devices
           valid=1
           for device in $RET; do

Extract of the resulting /var/cache/debconf/config.dat:
Name: grub-pc/install_devices
Template: grub-pc/install_devices
Value: /dev/disk/by-id/ata-Samsung_SSD_850_EVO_mSATA_1TB_S246NWAG406372X
Owners: grub-pc
Flags: seen
Variables:
 CHOICES = /dev/sda (1000204 MB; Samsung_SSD_850_EVO_mSATA_1TB), - /dev/sda5 (2999 MB; /)
 RAW_CHOICES = /dev/disk/by-id/ata-Samsung_SSD_850_EVO_mSATA_1TB_S246NWAG406372X, /dev/disk/by-id/ata-Samsung_SSD_850_EVO_mSATA_1TB_S246NWAG406372X-part5

Name: grub-pc/install_devices_disks_changed
Template: grub-pc/install_devices_disks_changed
Value:
Owners: grub-pc
Flags: seen
Variables:
 CHOICES = /dev/sda (1000204 MB; Samsung_SSD_850_EVO_mSATA_1TB), - /dev/sda5 (2999 MB; /)
 RAW_CHOICES = /dev/disk/by-id/ata-Samsung_SSD_850_EVO_mSATA_1TB_S246NWAG406372X, /dev/disk/by-id/ata-Samsung_SSD_850_EVO_mSATA_1TB_S246NWAG406372X-part5