Problem installing Epson Perfection V370 scanner drivers

I just freshly installed an Ubuntu 20.04 system, installed the driver for the V370, and it is working fine.

My steps were:

Install sane sane-utils libsane-common xsane
Install the Epson driver using ./install.sh
Copy the 79-udev-epson.rules (the same from 18.04) to /etc/udev/rules.d/

Now everything is working fine.


Prerequisites

Finding the UUID of the partition

Run this command in the terminal

sudo blkid

You will get something like this

/dev/sda1: UUID="FA286F4C286F06CB" TYPE="ntfs"
/dev/sda2: UUID="328E-CDB6" TYPE="vfat"
/dev/sda3: LABEL="7programs" UUID="01CAB88B789D7370" TYPE="ntfs"
/dev/sdb1: LABEL="TempBAKUP" UUID="EF54-7F8C" TYPE="vfat"
/dev/sdb3: LABEL="New Volume" UUID="B62A57642A5720A3" TYPE="ntfs"
/dev/sdb5: LABEL="7programs" UUID="01CAB88B789D7370" TYPE="ntfs"

Find the data partition that you made earlier and note down the UUID

Making sure that the partition mounts at bootime

Duplicate your fstab file:

sudo cp /etc/fstab /etc/fstab.$(date +%Y-%m-%d)

Open the original fstab in a text editor:

gksu gedit /etc/fstab

and add these lines into it

# (identifier)  (location, eg sda5)   (format, eg ext3 or ext4)      (some settings)
UUID=????????   /media/home    ext4          nodev,nosuid       0       2

and replace the "????????" with the UUID number of the intended /home partition found above.

 Using Usermod

Use this command to just change the homedir

usermod -d /media/home username

replace username with your username

Now move all of the files in /home/ to /media/home/ with this command:

cd / && sudo mv /home/* /media/home

Now, delete the old home folder

sudo rmdir /home --ignore-fail-on-non-empty

Sources:

https://help.ubuntu.com/community/Partitioning/Home/Moving

http://www.spiration.co.uk/post/1294/Unix-/-Linux-change-a-user%27s-home-directory---usermod


USB ports will not recognize flash drive

First, you can try unplugging and plugging the device back in.

Also, i've noticed sometimes the device doesn't mount until I click on the device in thunar (or nautilus). First, open the file manager (nautilus, thunar, whatever) and click on the device icon down on the left to mount the device.

To manually mount a device, open a terminal and type the following commands:

First, list all devices:

lsblk

here's an example of the output

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 232.9G  0 disk
├─sda1   8:1    0 223.4G  0 part /
├─sda2   8:2    0     1K  0 part
└─sda5   8:5    0   9.5G  0 part [SWAP]
sdb      8:16   1   3.7G  0 disk
└─sdb1   8:17   1   3.6G  0 part
sdc      8:32   1   1.9G  0 disk /media/myawesomeusername/8817-272B
sr0     11:0    1     2K  0 rom

In this example, we have the hard drive at /dev/sda, an unmounted USB drive at /dev/sdb and a mounted USB drive at /dev/sdc.

To mount the unmounted USB drive at /mnt, we would run the following command:

sudo mount -o rw /dev/sdb1 /mnt

The contents of the drive should now be available in the folder /mnt.

To explain mount mounts the drive, -o rw is for the option read write, /dev/sdb1 is the usb partition we want to mount, and /mnt is the mount point where the contents of the drive will display.

To unmount the drive, either click the eject button or run the following command:

sudo umount /dev/sdb1


system is in superuser mode how it change to normal mode

You get the output

Could not get lock /var/lib/dpkg/lock ...

when you start a second tool, that wants to do the same or similar things with the installed programs. Both the Software Center and apt-get 'want to do' the same or similar things. The lock is there to keep them from destroying things for each other.

When you close the Software Center, the lock should be removed, and you can run your apt-get command line

sudo apt-get install synaptic


Why won't my dell lattitude 5591 charge after installing ubuntu?

First of all check if your system recognize your battery, to do this type the following command in your terminal

upower -i /org/freedesktop/UPower/devices/battery_BAT0

The /org/... path can be found with the command upower -e (--enumerate).

If your system detects battery, try next steps:

go to BIOS (to enter the BIOS, I pressed ENTER at boot, and then F1)
in the BIOS, go to Config, then select Disable Built-in Battery. This disables the battery completely (i.e. disconnects the battery circuit logically)
unplug the charger
press the power button for about 10 seconds
plug the charger back in
boot up


How do I enable the "backports" repository?

Command-line/Server Instructions
Backports are enabled by default, here's how you can check to make sure they are turned on.
Ensuring Backports are enabled
To enable the backports manually make sure the following line is in your /etc/apt/sources.list:
deb http://archive.ubuntu.com/ubuntu release-backports main restricted universe multiverse

Replacing release with the current distribution you are using ( precise for 12.04 for example).
Now the next steps will depend on whether you want apt to always use packages from the backports or whether you want to only use the backports only when manually specified.
Always use the backports..
Ubuntu 11.04 and newer are automatically configured to only use the backports when manually specified. If you want to always use the backports when installing you'll need to add the following lines to /etc/apt/preferences (the file might not exist yet; that's fine):
Package: *
Pin: release a=<release>-backports
Pin-Priority: 500

Make sure you substitute release with your current release.
Using the backports manually..
If you only want to install packages from the backports when manually specified you'll need to add this to /etc/apt/preferences:
Package: *
Pin: release a=<release>-backports
Pin-Priority: 100

Again substituting <release> for your current release.
note: You will need root privileges to modify /etc/apt/preferences.
Installing from the backports..
If the backports are configured to be used manually you will need to add /release-backports to the end of the package name when installing a package (substituting release for your current release).
For example, if you're using 12.10 Quantal and have configured the backports for manual install you would install amarok with this command:
sudo apt-get install amarok/quantal-backports

Source: Ubuntu Backports - Ubuntu Wiki


Windows 10 cannot boot after installing ubuntu 16.04

You can resolve this issue by reinstalling and updating Grub.

Be sure to boot in UEFI mode.  You can verify this after you have booted to the liveUSB by running this command:

$ dmesg | egrep "EFI v"

If you have booted UEFI you will see the version as the output (example: EFI v2.31 by American Megatrends).  If you are in Legacy the output will be empty.

Follow the steps in this Answer:
Installing Windows 10 on partition removed Ubuntu option for UEFI

From your pastebin information, use these arguments for the steps:

/dev/sdX# = /dev/sda9  (This is your Ubuntu installed partiton)
/dev/sdY# = /dev/sda2  (This is your EFI parition)
/dev/sdZ=   /dev/sda   (This is the drive that you will boot to set via your BIOS)

After performing the steps, all your recognized OS's will be added to the Grub menu.

I understand you said you had problems when trying to repair by using Windows Boot repair utility.  It's my experience that Grub is more robust for booting the various OSes that are detected as installed.


Server - connect to existing PPTP vpn and serve web traffic over vpn

Install pptp-linux along with other PPTP module ,

Add your provider at /etc/PPP/peers/VPNPR

Connect to VPN using "pon VPNPR"


I have the same ultrabook and I managed to fix mine with the above suggestion. I first ran:

sudo modprobe -r ideapad_laptop

Then I created a blacklist with:

sudo nano /etc/modprobe.d/myownblacklist.conf

Added the following line:

blacklist ideapad_laptop

Rebooted and Wifi working fine from then on. I'm running Ubuntu 14.10 Gnome 3 Edition and works pretty well. Hope this helps


How do I recover a specific file from BACKUP with 16.04.1?

I have discovered that I am able to restore specific files using the Files application. Navigate to the nearest path of the files or folders that you would like to restore and right click. Select 'Restore Missing Files...'. The backup application will scan through all of the backups and provide a list of previous backups.

I hope this helps.


Open nautilus with:

sudo nautilus
Go to /usr/share/X11/xkb/symbols
Open pc file with gedit.
Change the line

key <NMLK> {   [ Num_Lock      ]   };

To

key <NMLK> {    [XF86Bluetooth,       Num_Lock      ]   };

6. Save and close the file.

Run

sudo dpkg-reconfigure xkb-data
Restart the computer.

Now you will be able to use NumLock as a hotkey.

Also check this, in KDE, if you want the keypad enter numbers:


VirtualBox doesn't run x64 VMs with Vagrant on Ubuntu 12.04 x64

The reason was in the BIOS: for Lenovo Edge E545 there is an inversion for the Virtualization Technology setting value: "Enabled" means "Disabled", and "Disabled" means "Enabled".


The first boot: Automate wizard and optimize

The standard method for pressed on ubuntu 20.10 is cloud-init its enabled by default and it can be used with the Ubuntu 20.10 Installer.     I use USB sticks for this purpose however cloud-init can be used to request the configuration data over the network.
Its very powerful and I frequently use to do unattended installs just boot it up and come back later to tell it to reboot the first time.
Perfect for the busy administrator I suggest you play with it in a virtual environment as its a quick learning curve.   Say with multipass or virtualbox.
https://ubuntu.com/blog/using-cloud-init-with-multipass
https://ubuntu.com/server/docs/install/autoinstall
https://ubuntu.com/server/docs/install/autoinstall-quickstart
https://discourse.ubuntu.com/t/automated-server-installs/16612
https://gist.github.com/bitsandbooks/6e73ec61a44d9e17e1c21b3b8a0a9d4c


difficulty transferring file to android phone

While not a direct answer to your question, I would recommend using Airdroid.  It's an app that runs a server on your phone; you can then access its contents from http://web.airdroid.com/.  It lets you transfer files to and from the phone as well as manage files, photos, SMS, etc.


iPython runs on Python 3 instead of Python 2

iPython is a python3 script itself so go to a terminal and type:

sudo nano /usr/local/bin/ipython

and change python3 into the default python and it'll run Python 2.

If that doesn't work, ensure you've got a compatible version of Python and iPython.


Cannot play media on Acer Aspire One AO751h

How much RAM do you have? I've always had the best luck with VLC on ubuntu. You will still need to make sure you have the restricted extras installed. Ubuntu doesn't come with the media codecs to playback a lot of stuff unless you check the box.

Can you describe what makes the mp3 unlistenable? can you also provide some system monitor screenshots during playback? This could be your audio drivers, and but I want to make sure your processor isn't getting slammed with the decoding first.


Will Mir improve multiple-monitor support?

As per Ubuntu Blueprints for 13.10.

This blueprint is meant to capture the tasks associated with enabling multimonitor support with Mir, targeting the 13.10 xmir release. This would include hotplugging monitors, as well as projectors. The effort should be focused on delivering for the 13.10 desktop experience, however the architecture should support the future inclusion of mobile multi-display.

For complete detail see Support for Multimonitor

Source:Support for Multimonitor


I had lots of similar problems on a fresh install of 12.04 from the Live CD. The Live CD was working fine, but not the installed system.

Flicker/pixelation on the login screen. After login, eihter the same, making windows unreadable, or nothing but a clean background (no menus, no launcher, nothing).

unity --reset and several reboots didn't help.

That was an install of Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425).

A fresh install of the latest version (Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)), works fine now.


Why won't windows remember their size in Lubuntu?

This is both a Window manager and an application-specific thing. Window managers such as Compiz are able to remember the size of your windows and open them in the last used sized if setup correctly. However, on Lubuntu, the Window Manager is Openbox, which does not support this feature.

Some applications handle this themselves, and some even have it in their preferences. If you really need this feature you can use Compiz. However, most Compiz features require compositing (in 3D), so your hardware needs to support it.


Japanese input on 16.04 with Fcitx and Mozc

Install Japanese. One of the installed packages is fcitx-mozc.
Close Language Support and open it again.
Select fcitx as the Keyboard input method system.
Log out and log in again.
Click the icon at the very right of the menu bar and select System Settings.
In the Personal section, click Text Entry.
Click the + button, select Mozc (Fcitx), and click Add.

More info


Same issue here.
I have dissabled hardware acceleration in chrome system settings and it worked.


Did you try quickly?

quickly package --extras

This will use the /opt directory.


Running two PostgreSQL servers in same Ubuntu machine

Please let us know in an Ubuntu 14.04 Machine is it possible to run same PostgreSQL 9.4 Instances in same machine with different ports.

Yes, that's why Ubuntu has pg_wrapper.

See https://help.ubuntu.com/community/PostgreSQL and the manual for pg_createcluster, pg_ctlcluster, etc.

Unfortunately there does not appear to be a wrapper for pg_basebackup. So you'll need to take a base backup manually if you want to run a replica. You can pg_createcluster, stop it, delete the data directory, and replace it with a base backup.


How to enable open source radeon driver for a Radeon HD 5570?

Do this to remove all the fglrx traces from your system:

sudo apt-get purge fglrx*

Remove your xorg.conf

sudo rm /etc/X11/xorg.conf

Reinstall xorg

sudo apt-get install --reinstall xserver-xorg-core libgl1-mesa-glx:i386 libgl1-mesa-dri:i386 libgl1-mesa-glx:amd64 libgl1-mesa-dri:amd64

Configure Xorg

sudo dpkg-reconfigure xserver-xorg

Reboot:

sudo reboot

After the reboot all the fglrx drivers will be gone, you will be using default ones.


Keys repeat too fast, regardless of option in settings

Apparently adding a new keyboard Input Source (in System Settings -> Text Entry) and then re-selecting the previous one has fixed the problem.

Edit: I also ran sudo apt-get install --reinstall ubuntu-desktop prior to rebooting, so that could also be the reason why the problem disappeared.


How can I install 'restricted-extras' offline?

Downloading the ubuntu-restricted-extras package itself wont help you much. It is actually a "meta-package", ie, a package with no "real" content, but with a list of dependencies. Thats why its size is so small.

When you try to install it, it checks the dependencies and downloads and installs them. And those are a few tens of megabytes.

So, if you want a complete offline install, i suggest this:

Go to any computer with internet, and use a Live CD/USB Ubuntu session. (so you have a clean OS with no extra package installed)
Open Synaptics (Administration -> Package Manager), use the Quick Search for ubuntu-restricted-extras
In the list, double-click it. On the dialog window, click Mark.

Click Apply.
It will show a window of all the packages that must be installed. Those are the ones you need to download and install in your offline machine.

Either download them manually, or check the "Download Package Files Only" checkbox. The DEBs will be downloaded to /var/cache/apt/archives
You can also use File -> Generate Package download script option. Create a folder for the script, save it, then run it. All DEBs will be downloaded to that folder. Copy the whole folder to a USB/DVD, then use File -> Add downloaded packages option in the offline computer.

And, VERY important: both the offline and online computers must have the SAME architecture. (meaning 32/64 bits, OS, etc). So the package downloaded in one will be the correct one for the other.


reboot problem-loosing my software installed

Installed Ubuntu or just used as live mode??
I don't know the permanent solution.
Temporary solution i.e. do not restart VirtualBox Ubuntu OS, just save machine state.


Ubuntu Installer Doesn't Start from a Separate ISO Partition [Unetbootin]

Adding the unetbootin partion to your boot menu

Download EasyBCD (just press Download).
Select "Add New entry".
Go to the operating system tab
select "linux/BSD"
Give it an name (example "install ubuntu")
Select the correct partion (the partion on the image is an example can be diffrent on your system!)
Press add entry
Reboot and select "install ubuntu" in the (windows) dual-boot menu
After installation you can now remove the  install ubuntu" partion using gparted and follow this guide to add the free space to your ubuntu system.
Press upvote !!!

Installing from a ISO file.

Download EasyBCD (just press Download).
Select "Add New entry".
go to the portable/external media tab
Give it an name (example "install ubuntu")
Select the ubuntu ISO path
And press "Add entry"
Make a new partion using disk-management (max size you can maby)
Reboot your system.
Select "ubuntu install" in your (windows) dual-boot menu.
Install ubuntu on that new partion.
Than you have windows dual-booted with Ubuntu
You can now remove the windows partion using gparted and follow this guide to add the free space to your ubuntu system.
Press upvote !!!

DON'T REMOVE THE WINDOWS PARTION WITH THE INSTALLER! REMEMBER THE DISK IS LOADED FROM WINDOWS!!!


Upgrade to Ubuntu 13.04 Problem - Boots into Blank Black Screen

I had this happen, I had to experiment by loading up previous versions as listed in the grub 2 boot selection screen. then when i found a kernel that loaded I set it as default.

what I had discovered by searching google, was for some reason 13.04 places two unusable kernels in the boot selection. I had 3.8.0-19 and 3.5.0-28 which are non functional kernels. the kernel that is needed was 3.2.0-40. after removing and setting the right kernel in grub to the new default , all was fine and 13.04 works beautifully


Kernel Panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

You are missing the initramfs for that kernel.  Choose another kernel from the GRUB menu under Advanced options for Ubuntu and run sudo update-initramfs -u -k version to generate the initrd for version (replace version with the kernel version string such as 4.15.0-36-generic) then sudo update-grub.


How to sign snaps without pushing or pushing it to snap store?

Only snaps which are uploaded to the store will be signed by the store.


The BSNL helpline and staff are generally familiar with MS Windows and may not be too helpful but if they are, it will be a pleasant surprise.

I'm assuming that: the modem is an ADSL router; you are dual booting with MS Windows; and you have no problem connecting via MS Windows.

Click on the network manager icon in the top right corner of your
screen.
Choose "edit connections" from the drop-down menu.
Click on "DSL" and then on "add". (You maybe prompted to provide your Ubuntu login password at this or some point.) You can give the connection a name other than DSL1 connection, if you wish.
Enter your user ID and password and "available to all users".

That should do it. If you are not on an unlimited plan, you may not want to connect "automatically".


Error when running apt-get update for nordvpn

sudo apt-get update --allow-insecure-repositories

this will bypass the warning and will most probably solve your problem. And you should check out about the warning using command
man apt-secure

Going through the text you will understand why unsigned repositories are not allowed by default. In simple terms if a repository is not signed then there are more chances of containing a malicious content.
You can also download the deb file separately and then install it.
wget https://repo.nordvpn.com/deb/nordvpn/debian/pool/main/nordvpn_3.8.10_amd64.deb -P ~/Downloads/

Hope it solved your issue..


Why are most laptop wireless and dedicated graphics drivers are proprietary?

When a manufacturer produces a wireless or graphic card, they also produce the driver to make it work. Only they know how they work, so the're the first people to have the knowledge to produce drivers. Many of the manufacturers believe either by commercial purposes or security issues, that theirs drivers are the most suitable, and they have the power to make it open or closed source.
Producing open source drivers sometimes require a lot of hard work and reverse engineering, and because most of this work is made by people doing it for free, that's why you see more proprietary than open source drivers.


Is there any software for flashing nokia mobile phones ?

No, there isn't one available for Linux, you are mostly stuck with Windows.


Dia (Click to install)

  Dia is roughly inspired by the commercial Windows program 'Visio,' though more geared towards informal diagrams for casual use. It can be used to draw many different kinds of diagrams. It currently has special objects to help draw entity relationship diagrams, UML diagrams, flowcharts, network diagrams, and many other diagrams. It is also possible to add support for new shapes by writing simple XML files, using a subset of SVG to draw the shape.

You can also use Pencil

  The Pencil Project's unique mission is to build a free and opensource tool for making diagrams and GUI prototyping that everyone can use.


You have to recover the RAID5 setup within the NAS, using the tools available there. You can't expect to recover files from the nas-disks looking at them one by one in Ubuntu, since data is spread across all four disks. And you probably can't rebuild  the raid setup under Ubuntu.


Check the pool definiton of php-fpm (www.conf) which is in /etc/php/7.0/fpm/pool.d. I think that you are trying to start the php-fpm process as user "vagrant" - a user that doesn't seem to exist in the box.
The user and the group www-data is used to run php-fpm:
user = www-data
group = www-data


Is there a Relational Algebra software for Ubuntu?

Here's a link to "relational", which is a GUI-based relational algebra application.  According to the site, it is an "educational tool" so I'm not sure if it's exactly what you're looking for or not.

You should be able to install it by running the following command from a terminal session:

sudo apt-get install relational


You are getting the error :

/BIN/BASH^M: bad interpreter: No such file or directory

because there is no file named /BIN/BASH in Linux systems (unless you create one yourself). All Linux systems are case-sensitive, so #!/bin/bash and #!/BIN/BASH are totally different.

To solve the interpreter related issue, make the shebang as :

#!/bin/bash

Or prefarably :

#!/usr/bin/env bash

Also you seems to have carriage return as your line terminator, but Linux systems use line feed to terminate lines. So you should correct it yourself or use a simple program line dos2unix to do the job.

You can simply do the conversion by :

dos2unix filename

It is not installed by default, you can install it by :

sudo apt-get install dos2unix


How to find architecture of my PC and Ubuntu?

The command is uname -m.

Open a terminal try using uname -m command. This should show you the OS architecture.

If it gives any output like ix86, where x is 3,4,5 or 6, Your OS is 32bit.

You can also see the Ubuntu architecture by Opening "System monitor" and going in the System tab.

Difference between hardware platform and Processor type:

There is a difference between the hardware platform (which is given by -i switch) to the CPU type (given by -p switch).

The hardware platform tells us which architecture the kernel is built for (may be optimized though for later versions). It can be a i386.

However the Processor type refers to the actual processor type of your machine such as i686 (P4 and later builds).

Thanks to Schotty of this this page. Here is an answer from Unix stackexchange site on the same topic, though I didn't find the language enough clear (completely my fault).


You can use simple for loop:

#!/bin/bash

for i in *.pdf; do
   pdftoppm -png -rx 300 -ry 300 $i ${i%.pdf*}
done


Program for Ubuntu to detect cat-like typing?

None found.

A search of the links above, plus a web search, and a visit to https://alternativeto.net/platform/linux/ shows no Linux equivalent for PawSense, and its web page is very specific that Windows is required to run it.

However, you could use Kittydar or similar systems to watch for your cat and turn off the power lead to your keyboard when detected, but more hardware would be required.


Cannot automatically start JIRA via init.d script

For anyone who runs into this on Ubuntu 18.04, this is apparently a known bug in Jira and one that hasn't been addressed and seems it may not be.

To resolve this, you need root access (or sudo) and need to edit /etc/init.d/jira to add the following lines immediately after the #!/bin/bash line

### BEGIN INIT INFO
# Provides: jira
# Required-Start: $network $local_fs $syslog
# Required-Stop:
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: JIRA Server
# Description: JIRA Server
### END INIT INFO

Once this is done, run systemctl enable jira as root or with sudo.

This will get the stock init script that ships with Jira to properly start the service when the system boots.


Solution 1
Easiest way if only that one user ubuntu and www-data need access would be
sudo chown ubuntu:www-data <path/to/file or directory>

this gives ownership to the user ubuntu but still keeps the ownership for the group www-data.
So you control what ubuntu can do by
sudo chmod u<+|- permission> <path/to/file or directory>

and you control what www-data can do by
sudo chmod g<+|- permission> <path/to/file or directory>

or simply use complete permission masks (see example below).

Example:
User ubuntu shall be able to read(r), write(w), execute(e)
www-data shall be able read(r), execute(e) but not write(w)
other users shall be able to do none of those
sudo chmod u+rwx <path/to/file or directory>
sudo chmod g-w+rx <path/to/file or directory>
sudo chmod o-rwx <path/to/file or directory>

or using a permission masks (helpful generator)
sudo chmod 750 <path/to/file or directory>

Also interresting for your case might be the -R parameter for both commands, applying ownership and permissions recursively on the content of a folder.
For more information about options and parameters see
man chown and
man chmod

Solution 2
I would rather NOT add a user to a system functional user's group as suggested in the comments like
sudo usermod -a -G www-data ubuntu

as this is a really dirty way of granting a user permissions because he could also mess up things...
Instead if you want you could add a completely new group using groupadd (see man groupadd)
groupadd <group name>

add all users who shall have the permissions on the file(s) to this group
sudo usermod -a -G <group name> ubuntu
sudo usermod -a -G <group name> www-data

(for more information see man usermod)
and now set the ownership of the file(s) to this group
sudo chgrp <group name> <path/to/file or directory>

than you set the permissions as described before but this time only for the
group (read(r), write(w), execute(e))
sudo chmod g+rwx <path/to/file or directory>
sudo chmod u-rwx <path/to/file or directory>
sudo chmod o-rwx <path/to/file or directory>

or using the mask
sudo chmod 070 <path/to/file or directory>

Note that using this solution you lose the control over the different permissions for ubuntu and www-data.


How to grow RAID 1 following disk upgrade?

mdadm can not grow the RAID past partition boundaries. You should have enlarged the partitions before re-syncing each drive, then the grow should have worked. Can you tell us which metadata format you are using? In a new install it should be 1.2 but if it's sufficiently old it may be 0.90. Growing in your situation would be easier if it was 1.2.

mdadm --detail /dev/md1
/dev/md1:
        Version : 1.2

If it's 1.2, all you have to do is make the partitions (sdb2 sda2) larger. Make sure only the end of the partition moves, the start must remain the same, or your RAID will be broken. If you are unsure, do it for one disk only, so the other can still save your behind in case something goes wrong. You can do this with fdisk, but a better alternative is parted or even gparted if you prefer a GUI.

For parted, the following command should work (dangerous, writes partition table without asking):

parted /dev/sdb unit s rm 2 mkpart primary 609374208 100%

Check fdisk output again if it looks correct; reboot to see if everything still works (/proc/mdstat should show the RAID being in sync UU); do the same for /dev/sda and then after another reboot, try to grow again.

If it's still 0.90 metadata, I'd take this opportunity to build a new RAID 1 with 1.2 metadata. In a live CD, fail one drive, create a new RAID on it with one drive missing, dd or rsync -aAHSX the data over, add the other drive, etc.

For growing, I think you'd still have to fail a drive, enlarge the partition, then re-add it. 0.90 stores the metadata at the end of the device and it will not be found if you move the end by enlarging the partition.


This worked for me: Re-check and repair owner and rights of the backup folder.
context:
I tryed and move the "old" backup folder, and create new one for fresh backup more than month ago. New backup works like a charm, But today exactly the same error appeared again!
But today I know, that I did some changes on the server, and there was misconfigured owner of the backup folder. Whenever I "chowned" the folder, backup is working again.
I moved back the "old" backup folder which did not work and was not used for about 6 months, and re-set the owner / rights. The backup is working again and full backup is creating just right now.
I think, that this should be fixed:
Backup could check the rights (or maybe better, it could catch exeptions) of the backup folder, including subfolders and files, and return valid error response in any cases.


Disable indicator-datetime-service pop ups

It wasn't easy to find an answer, since this feature is completely undocumented, but I did it. I had to download the source code of the indicator-datetime and find some code related to this alert. A few quick searches for service and notification led me to a variable called cal_notification_enabled and two constants:

SETTINGS_NOTIFY_CALENDAR_PATH- /com/ubuntu/NotificationSettings/com.ubuntu.calendar/calendar/
SETTINGS_NOTIFY_ENABLED_KEY - enable-notifications

dconf-editor wasn't helpful as I couldn't find this parameter there, but a quick Google Search unveiled the truth. This functionality is somewhat important in Ubuntu Phone and it can be switched on and off in the calendar app. On desktop, however, there's no switch for it in calendar's settings and it seems that it's true by default. It can be disabled from console though:

gsettings set com.ubuntu.notifications.settings:/com/ubuntu/NotificationSettings/com.ubuntu.calendar/calendar/ enable-notifications false

After switching this setting to false no alerts will disturb your work.


GNURadio Live CD installed on HDD adding persistence

Options for Multiple Persistence

You can add up to 4GB persistence by adding a casper-rw file and 4GB more adding a home-rw file, (re-labeled casper-rw file), to the gnu radio partition root. You will need to add the word persistent to your grub.cfg file along with the persistent-path to these files, (or to syslinux.cfg or txt.cfg if booting using Syslinux).

You can not have multiple Persistent partitions on a drive.

If you want multiple Persistent installs on the HDD, try YUMI, The persistent casper-rw files are of unlimited size if you are booting BIOS, They are limited to 4GB if you are using the UEFI version of YUMI.

You can also create multiple Full installs on HDD, by installing to multiple partitions, each as you would to internal drive. They will have unlimited persistence. Good to start with a GPT partition table as you can fit more partitions.

Ref: "Handmade" live usb multisystem or Multi-partition multi OS bootable USB and Install grub on a multi-partition and multiboot USB flash drive


Add command to lauch a new application from terminal

You can add symbolic link to /bin or /usr/local/bin for executable file. For example:

ln -s /home/username/programs/bluegriffon/EXECUTABLE.sh /usr/local/bin/bluegriffon


How can I play .camrec files made in Camtasia?

You can use 7-Zip to open .camrec files, it's possible it's just a renamed extension. The video is .AVI inside, however, if you've recorded system audio, it stores it as a separate WAV file, and the Microphone or other selected audio source is encoded into the AVI. I had a great batch process to unpack, remux (to overwrite the microphone with system audio) and encode camrecs to AVI with commandline 7-Zip and virtualdub, but unfortunately lost it in a hard drive crash a few months ago. Have to work on it again... in any case, just knowing 7-Zip can handle camrecs without having to open Camtasia Studio is valuable enough. I know there's a 7-Zip linux port; none for virtualdub but it shouldn't be too hard to find an alternative.


How do I copy files that need root access with scp?

You're right, there is no sudo when working with scp. A workaround is to use scp to upload files to a directory where your user has permissions to create files, then log in via ssh and use sudo to move/copy files to their final destination.

scp -r folder/ user@server.tld:/some/folder/you/dont/need/sudo
ssh user@server.tld
 $ sudo mv /some/folder /some/folder/requiring/perms
# YOU MAY NEED TO CHANGE THE OWNER like:
# sudo chown -R user:user folder

Another solution would be to change permissions/ownership of the directories you uploading the files to, so your non-privileged user is able to write to those directories.

Generally, working in the root account should be an exception, not a rule - the way you phrasing your question makes me think maybe you're abusing it a bit, which in turn leads to problems with permissions - under normal circumstances you don't need super-admin privileges to access your own files.

Technically, you can configure Ubuntu to allow remote login directly as root, but this feature is disabled for a reason, so I would strongly advice you against doing that.


Resolution was reset after upgrade, Xrandr failed to get size of gamma for output default

Nevermind, I have found the solution here:
https://www.fosslinux.com/41008/install-nvidia-driver-on-ubuntu-command-line-and-gui-ways.htm
Basically, the upgrade somehow uninstalled my Nvidia drivers.
I just reinstall them with sudo ubuntu-drivers autoinstall before rebooting.


How do I find and use the gnome terminal?

There is also the keyboard shortcut:
Ctrl+Alt+T


Why is GNOME Terminal not showing in list of applications when I try to open a file on Ubuntu 18.04?

Interesting question, I believe an 'open with Terminal' option (to execute a script) is not there by default, but you can certainly create one. To do this follow the steps below.

Create an empty text file in your ~/.local/share/applications/ directory.
Open it with a text editor.
Add the following lines to it.

[Desktop Entry]
Name=Open with Terminal
Comment=Run the script in a Terminal window
Exec=/bin/bash -c '%U; exec bash'
Type=Application
Terminal=true
Icon=utilities-terminal
NoDisplay=true

Save the text file (or rename it) with a .desktop suffix, say as open-with-terminal.desktop.

Now you should find an entry called 'Open with Terminal' in the 'Open with Other Application' dialog.

But this might be an overkill for your actual goal.  If you just want to execute a script from your file manager, then see this: How do I run executable scripts in Nautilus?


Wine on Edubuntu 11.10 can't find exe files entered in Winecfg

You need to use the full Linux path

Wine does not find executables using the drives you enter into Winecfg.

In order to execute your files from the command line, you need to find their path in Linux.

For example, if the file is on your CDROM, you need to use wine /cdrom/setup.exe in the commandline.

Why Winecfg allows you to add executables

The reason for this is because some applications need "workarounds" or native dlls in order to run on Linux via Wine.

Only add applications here if they need a library override.

Winecfg allows you to add these applications so that you can configure their requirements easily, but it does not mean that Wine will automatically find the files when you type "wine appnamegoeshere.exe".

How Wine Finds executables

Much like Windows, Wine only finds files automatically if they are in the "system folders". These include C:\, C:\Windows, and C:\Windows\System32 (and a few others).

Note: These are drive mappings, and do not make executables and files automatically visible to Wine

Adding D:\ to the list of drives does not make executables automatically visible to Wine. Instead, what it does, is make it easier for applications (and you) to find files as you would on Windows, using Drive Letters and the usual path format from Windows.


How do I run a Python script in the background and restart it after a crash?

The simplest way to do this is place this in /etc/init/something.conf:

start on runlevel [2345]
stop on runlevel [016]

respawn
exec python /path/to/your/script.py

Respawn will start it back up if it is killed or exits non-zero (like an uncaught exception). This will work going back to Ubuntu 10.04.

If you have 12.04 you can get more fancy. The above will run your script as root. In 12.04 you can add setuid/setgid:

start on runlevel [2345]
stop on runlevel [016]

respawn
setuid nobody
setgid nogroup
exec python /path/to/your/python.py

If your script exits when there is no network available and you plan to run it on an unstable network connection, well, you should fix that and just make it stay alive/retry. But if you can't, you may also need to have it manually started whenever a network device comes up. So you can place this in /etc/network/if-up.d/yourscript (make it executable with chmod +x)

#!/bin/sh
exec start wait-for-state WAITER=$IFACE-yourscript WAIT_FOR=something

Where yourscript is just something arbitrary and unique to this particular script, and "something" is the same as the job name (such as the /etc/init/something.conf suggested earlier).


Ubuntu comes with Unity as default desktop environment. You can always switch back to a lightweight desktop just as I did. I had installed Ubuntu on VMWare with Windows 7 host and it was running slow. After switching to Xfce desktop environment, everything is now working fine. (although a little less graphical effect).

You can switch to Xfce desktop by opening terminal and typing

sudo apt-get install xfce4

Source: 3 best Linux desktop environment


Can I recreate a destroyed /boot without reinstalling?

IF all the windows install did was delete the partition before you stopped it you can try something like testdisk to see if it can find the original partition's on the drive.

If windows started writing data to the drive it is entirely likely that that partition was overwritten.

There are also tools like R-studio linux which may be able to recover the data as well but that may end up being more of a hassle then reinstalling the boot partition.


I solved this by black listing the B43 driver and installing the STA driver.


Ubuntu 18.04.3 losing email and internet connection but not SSH

I think it has been a problem caused by an older version of Thunderbird. I have updated Thunderbird and Firefox to the latest versions and I don't seem to have this problem since then. I think the problem is specifically caused by the old version of Thunderbird trying to connect to the imap server at Yahoo. I can't be certain yet that this has solved it but if you are having similar problems, this might be the first thing to try.


Create bash file to open minecraft launcher

You can create a .desktop file that will do this. Bash file are usually run from the terminal, while .desktop files simply run a command, not necessarily needing a Terminal.

As for launching Minecraft, that's simple enough.

Run nano ~/.local/share/applications/minecraft.desktop in Terminal
Copy/paste this in to the file you just opened:

[Desktop Entry]
Comment="Launching Minecraft"
Terminal=false
Name=Minecraft Launcher
Exec=/home/USER/Java/jre1.8.0_25/bin/java -jar ~/Minecraft.jar
Type=Application
Icon=/home/USER/.minecraft/mc_logo.png

Save and close that file
Save this image in your ~/.minecraft folder as mc_logo.png:

And you should be able to find this in the dash and launch Minecraft without the Terminal!


I can not see a shared forlder under VBOXSVR from a XP Guest

Install the Guest Additions (this solved the problem for me):

From Devices select Insert Guest Additions CD
Navigate to the CD image from My PC
Run VBoxWindowsAdditions.exe as administrator and install the tools
Reboot when installation is complete

It should be visible now.


Install Network Printer Manually (Router : TP-Link TL-WR842ND)

I understand from the screenshot of your router, 192,168.0.1 is your router's address, and you have a separate "printer server" box (TP-PS110U)connected to the router by ethernet on one side and your printer's USB on the other side.

Step 1 says to go directly to step 4... However, step 3 explains the printer spooler web interface at http://192.168.0.10/ -- it may be worth a visit there to check everything is in place.

According to Step 6, the spooler is at 192.168.1.10 by default (to confirm with the information found on the web interface of the print server at http://192.168.0.10), that's where you should find your printer, not at 192.168.0.1, which is your router.

Does it change something?


I think the answer above is incorrect. I also can not start cheese on my 12.04 setup with an NVIDIA GT240 graphics card. I am using the proprietary driver and the webcam works perfectly with Skype. Camorama does not work either.

I am using 12.04 updated today 18th April. This is Beta 2 updated.

I did a fresh installation on another machine (using the daily build) and the problem does not occur. I would suggest doing a fresh installation at the end of the month.


you are not in that directory where configure file reside. so, you have to change directory to bwa directory and run command ./configure  it will work.
or
if you are facing problem to install bwa then follow step bellow

install git using

sudo apt-get install zlib1g-dev
sudo apt-get install git

then run command

git clone https://github.com/lh3/bwa.git
cd bwa; make
./bwa index ref.fa
./bwa mem ref.fa read-se.fq.gz | gzip -3 > aln-se.sam.gz
./bwa mem ref.fa read1.fq read2.fq | gzip -3 > aln-pe.sam.gz

i hope it will resolve your problem . for more info here


How to remove recommended and suggested dependencies of uninstalled packages?

If you want to remove recommended packages from your system, even if there are still some installed packages recommending (or suggesting) them, put the following in the file /etc/apt/apt.conf.d/99_norecommends (create it):
APT::Install-Recommends "false";
APT::AutoRemove::RecommendsImportant "false";
APT::AutoRemove::SuggestsImportant "false";

The documentation for these options is here.
Then, the next apt run should remove them all. If it doesn't, launch aptitude, and type g and g again.
This configuration also disables the automatic installation of recommended packages when using apt-get. For aptitude it can be done from the console GUI, menu Options > Preferences > "Install recommended packages automatically" (uncheck it).


keyboard shortcuts misbehavior Gnome 3.6

Try disabling the "Show location of pointer" using the Gnome Tweak Tool.


Ubuntu 20.04 can not enter the desktop after entering cold password authentication

I have encountered this issue very consistently as I am installing Ubuntu as a dual-boot system on an entire fleet of ASUS laptops from the X450 and X455 range. Without fail, this is how I resolved the issue.

Install Ubuntu (or re-install in your case)
Drop into TTY as soon as you first boot into Ubuntu, e.g. Ctrl+Alt+F3.
Run sudo apt update && sudo apt upgrade -y. For some reason during this stage the Desktop session will sometimes snatch away the screen from TTY and you will have to switch back to it.
Reboot after the upgrade and wait for everything to load in Ubuntu. I have not seen the problematic behaviour repeat itself since.


JDK/JRE explanation of comands for install

Check the man page of update-alternatives with man update-alternatives. The options are nicely explained there.

The Debian alternatives system is an interface between command used by an user for a particular function and the command chosen by system administrator for that functionality. This is a way by which admin can change the underlying command for that function without interfering with the command used by the user. Suppose an user use the command editor to edit a file and admin links the command to vi with update-alternatives via /etc/alternatives/editor; then a better editor vim becomes available and admin changes the link to vim, the user will still be able to edit a file with editor command.

The syntax is

  update-alternatives --install link name path priority

link = master command for user's use (e.g. /usr/bin/java which is accessible with just java because /usr/bin is searched for any commands by default)
name = name of the intermediate link under /etc/alternatives directory working as the interface between user's command and actual command(e.g. java which creates /etc/alternatives/java; user's command /usr/bin/java points to it. This is why you have to write java)
path = actual command set by administrator(e.g. /usr/lib/jvm/jdk1.7.0/bin/java; /etc/alternatives/java links to it)
priority = the command used by default, this is set by admin(e.g. 1 for highest priority or default, 2 for next highest priority and so on)

So, with this settings if you have more than one java installation, e.g. OpenJDK and Oracle's JDK then you can choose between them while keep using java as the command as an user and by setting the priority with update-alternatives --config java as administrator, which is actually changing the link between /etc/alternatives/java and the actual java program.

There is actually no difference between JDK's java and JRE's java. In fact in a JDK installation JDK's java is a symbolic link to JRE's java.


So it looks like fstab is being executed before your network stack is up. Here is one way to remedy that:

[1] Create a file at: /etc/network/if-up.d/fstab

[2] Add this to it:

#!/bin/sh
mount -a

[3] Make the file executable:

sudo chmod +x /etc/network/if-up.d/fstab

Anything placed in if-up.d will be executed only after the network it up and operational. THe "mount -a" directive will mount anything in fstab that isn't already mounted. So the next time you boot your shares should be mounted.


External monitor does not correctly display on GMA500

SOLVED! This issue was solved by change kernel version to 3.4!


Electrum crashes on launch, can not update Python, can not remove Electrum

Install dependencies:

sudo apt-get install python3-pyqt5

Download package:

wget https://download.electrum.org/3.3.8/Electrum-3.3.8.tar.gz

Verify signature:

wget https://download.electrum.org/3.3.8/Electrum-3.3.8.tar.gz.asc
gpg --verify Electrum-3.3.8.tar.gz.asc

Run without installing:

tar -xvf Electrum-3.3.8.tar.gz
python3 Electrum-3.3.8/run_electrum

Install with PIP:

sudo apt-get install python3-setuptools python3-pip
python3 -m pip install --user Electrum-3.3.8.tar.gz[fast]

Edit
Python 2.7 will not be maintained past 2020. Originally, there was no official date. Recently, that date has been updated to January 1, 2020.

Please avoid using Python 2.7


The 'partners' are companies that provide software that is approved by Canonical but for which the Ubuntu community is not providing updates. That's the responsibility of the partners themselves. The community however provides the install packages (builds the packages). For instance Adobe used to be a partner.

Independent are essentially providers that are not partners.

You can assume that these are safe. You only have to be cautious for repositories you did add yourself.


How to assign hot-keys to control Rhythmbox?

What do we need...
When rhythmbox is installed, there is a command based application called rhythmbox-client that can be used to control various aspects of Rhythmbox itself.
So how does it do it...
rhythmbox-client uses a process communication protocol called DBUS.  Its the same protocol that the Unity Sound Indicator menu uses.
You need to ensure that this plugin is enabled in Rhythmbox

How to I assign a short-cut key...
Launch Keyboard from the Unity Dash.

The important part is the command and assigning the short-cut itself.
The command you need to use is rhythmbox-client --play-pause
So what else can I control...
If you run rhythmbox-client --help this will give you a list of command line options which you can control Rhythmbox.
The most useful options for keyboard control are:

  --quit                                   Quit Rhythmbox
  --next                                   Jump to next song
  --previous                               Jump to previous song
  --seek                                   Seek in current track
  --play                                   Resume playback if currently paused
  --pause                                  Pause playback if currently playing
  --play-pause                             Toggle play/pause mode
  --enqueue                                Add specified tracks to the play queue
  --clear-queue                            Empty the play queue before adding new tracks
  --print-playing                          Print the title and artist of the playing song
  --print-playing-format                   Print formatted details of the song
  --set-volume                             Set the playback volume
  --volume-up                              Increase the playback volume
  --volume-down                            Decrease the playback volume
  --print-volume                           Print the current playback volume
  --set-rating                             Set the rating of the current song

There are other options which you can use in - for example - shell scripts as well.


Server 20.04 turn screen off after inactivity

SOLUTION (verified with Ubuntu 20.04 server running on a laptop)
Create a file:
sudo nano /etc/systemd/system/enable-console-blanking.service

And put this into the file:
[Unit]
Description=Enable virtual console blanking

[Service]
Type=oneshot
Environment=TERM=linux
StandardOutput=tty
TTYPath=/dev/console
ExecStart=/usr/bin/setterm -blank 1

[Install]
WantedBy=multi-user.target

Then change the file rights and enable the service:
sudo chmod 664 /etc/systemd/system/enable-console-blanking.service
sudo systemctl enable enable-console-blanking.service

And reboot the server. Now the screens blanks after 1 minute without keypresses, even before the login.


How to remove a blank and dead link/icon from Dash search

another file ~/.local/share/applications/jna_jar.desktop also need to be deleted. It seems to be openjdk brought by first time running pycharm.

[Desktop Entry]
Encoding=UTF-8
Version=1.0
Type=Application
Name=Welcome to PyCharm Community Edition
Icon=jna_jar.png
Exec=/usr/lib/jvm/java-7-openjdk-amd64/bin/java -Xbootclasspath/a:./../lib/boot.jar -classpath ./../lib/bootstrap.jar:./../lib/extensions.jar:./../lib/util.jar:./../lib/jdom.jar:./../lib/log4j.jar:./../lib/trove4j.jar:./../lib/jna.jar -Xms128m -Xmx750m -XX:MaxPermSize=350m -XX:ReservedCodeCacheSize=240m -XX:+UseConcMarkSweepGC -XX:SoftRefLRUPolicyMSPerMB=50 -ea -Dsun.io.useCanonCaches=false -Djava.net.preferIPv4Stack=true -XX:+HeapDumpOnOutOfMemoryError -XX:-OmitStackTraceInFastThrow -Dawt.useSystemAAFontSettings=lcd -Djb.vmOptionsFile=./pycharm64.vmoptions -XX:ErrorFile=/home/x/java_error_in_PYCHARM_%p.log -Djb.restart.code=88 -Didea.paths.selector=PyCharm50 -Didea.platform.prefix=PyCharmCore -Didea.no.jre.check=true com.intellij.idea.Main
StartupNotify=false
StartupWMClass=jetbrains-pycharm-ce
OnlyShowIn=Unity;
X-UnityGenerated=true

Several points done in the question was wrong.

1) Running sudo ls /usr/share/applications with sudo is nonsense. Your user can read the data. How do
you think you get the icons in Dash? Think about it instead of wildly
adding sudo to commands when you don't get what you expect.

2) The files in /usr/share/applications define the files using
configuration lines in the files. The filename has no bearing here. You
could rename them all to random letters and numbers and Dash would still
work as it does now.

3) Try grep -i pycharm /usr/share/applications/* to find out what should be deleted


How do I get keyboard to write Hiragana instead of Katakana?

I finally found out how to do this on Ubuntu 16.04!

Go to System Settings > Language Support
Click on Install / Remove Languages
Scroll down or type J and check the checkbox next to Japanese in the Installed column. After this, click on Apply Changes
Enter your password when you're prompted
Let the packages install
Log out (yes, this is necessary)
Open System Settings and go to Text Entry
Click on the small plus sign at the bottom of Input sources to use
Select the entry Japanese (Mozc) (IBus) from the list and click on Add
Japanese (Mozc) (IBus) should now show up inside the Text Entry window and Mozc should be available in the menubar's menu. You probably want to change the setting Use the same source for all windows to Allow different sources for each window and switch to New windows use the default source. Additionally, you eventually want to reassign the key to switch to the next input source. I normally use the Pause to toggle between languages.
Now fire up some text editor and try it by clicking on "Mozc" in the text entry menu, set the input mode to hiragana and type some Japanese. Switching between candidates is done by pressing the space bar and Katakana conversion is done by pressing F7.

Note: If you face any issues with different applications, it might help to restart the IBus daemon using ibus restart.

See also the original article archive.is by Moritz Molch. There are also screenshots there, which should make everything a little clearer.


Make your preferred path first:

PATH=/opt/msp430-47/bin:$PATH

Check it

echo $PATH

Fix permissions

sudo find /opt/msp430-47 -type d -exec chmod +rx "{}" \;
sudo chmod -R +rx /opt/msp430-47/bin


user not recognized from the recovery mode

Since this is a school setup, they are probably using LDAP for authentication, in which case you won't be able to modify group membership. You'll have to contact your school's IT department or system administrator.

You can't modify them because because any sane LDAP setup requires administrator access to the LDAP service to modify group membership (which is not the same as administrative access to an individual PC). Tools like adduser and usermod work on local users, which are set up in /etc/passwd and /etc/group.

To see how to configure an Ubuntu system as an LDAP server or client, see the Ubuntu LTS server guide article on OpenLDAP.


How to load a iptable matching module? Or is it required to load it expressly? Some related questions

You ask 4 questions. I can answer 3 of them.

Any required module will be loaded automatically by iptables when it is required. Some years ago, modules had to be specifically loaded. Some critical applications still force load the modules, so that there is no delay when iptables realizes it needs the module.

Now, the issue with your MAC related iptables rule, is bad syntax and not module loaded or not loaded. This line:

iptables -A INPUT -s 192.168.1.88 -m mac --mac-source 00-27-0E-33-4B-B2 -j DROP

Should be this:

iptables -A INPUT -s 192.168.1.88 -m mac --mac-source 00:27:0E:33:4B:B2 -j DROP

Your question about conntrack module listed 3 times, I do not know why. Perhaps because you are using it in 3 different ways, but that is just a guess.


I have a similar problem, but do not know the cause. "Occasionally" windows or dialogs of various apps come up with totally transparent content, or full screen apps have app name in top bar, but the rest of screen is totally transparent just showing the background. Totally closing and reopening the transparent dialog or app restores it to completely visible. I don't think I have anything set to be transparent, and cannot find any setting for that.

It occasionally happens with nvidia-375 or nvidia-378 with GTX 750 Ti or GTX 1060. But I am running stock 64-bit Ubuntu 16.10 because 16.04 seemed to blank all text during even cold boot (BIOS splash and grub menu totally black) until something (gui login or Win7) displays graphics. 16.04 boots fine on other older/newer computers, but I have not run them long enough to see if they exhibit the rare window transparency issue.

I did find a setting in CompizConfigSettingsManager that defaulted to screen refresh rate 50 and I changed that to its actual 60. But I will have to wait to see if random window transparency still happens.


For security reasons, CRON uses a very minimal shell environment. This includes a minimal PATH and HOME variables. In most cases, you want to use full paths for all commands.

So, I would suggest you first run:

$ which shutdown
/sbin/shutdown

Now you know the full path to that command and you want to use that in your CRON definition:

0 1 * * * /sbin/shutdown -h now

If you want to add variables to the shell (or need to in order to run certain commands) you can add or update them at the top of the file. For example:

PATH=/sbin:${PATH}
HOME=/root

0 1 * * * /sbin/shutdown -h now

Keep in mind that the handling of spaces and tabs is different (see the docs for details).

One variable which is often updated is the MAILTO=<your-email>. By default, emails will be sent to root for the root account. I prefer to use an alias (often defined in /etc/aliases). The alias allows me to send the emails to multiple administrators instead of just one person.

To become root, I use the following:

sudo su -

which I find cleaner than many other solutions. You can then edit the crontab of the root user with:

crontab -e

As you've shown in your question.

Otherwise, the leading zeroes are probably okay. I never put them there and the examples do not show such. Just in case, I would try without them as I've shown above.

For additional info, I would suggest you read the crontab manuals:

man crontab
man 5 crontab

The first one is about the command line.

The second one is about the file format. They talk about the shell variables. The PATH, the MAILTO, etc. It's a good read.


How do I fix "malformed line" errors when trying to run commands in apt?

Read the error messages.
The first one tells you which file, and which line has the error. Fix that error.
The second error was caused by the first error, and will probably go away when you fix the first error.
The third and fourth error messages indicate a different problem.
Either you're running a package installer program in a different terminal, or as a detached process, or you killed an installer process so rudely that it didn't release the look.
You can see if any current process has the lock file open by
sudo lsof /var/lib/dpkg/lock-frontend

If a process has the file open, consider killing it.
If no process is shown, simply remove the file.
sudo rm /var/lib/dpkg/lock-frontend

If rm can't find the file, the process that had the file open ("holding the lock") has released the lock and exited. This is the temporally unavalible part of the messages.


Gedit file browser panel does not appear

You can try simply select View -> Side Panel (or press F9) to show Documents or File Browser in the left. This left side-panel have two modes of operation - Documents

and File Browser.

They are switched by clicking on small arrow  in the right of current label.

If this does not help, you can try to reset Gedit settings with

dconf reset -f /org/gnome/gedit/

Also check Gedit Preferences (Edit -> Preferences), it should look like:

If it still does not work you can try to reinstall Gedit packages:

sudo apt-get install --reinstall gedit gedit-common


Onboard audio not working after graphics drivers set

Finally found an answer: the same as this question: Install the oem-audio-hda-daily-lts-vivid-dkms package from here.


Edit the grub configuration:

$gksu gedit /etc/default/grub

add:

GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

after:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

then update the grub and restart:

$update-grub && reboot


How can I configure Juju for deployment on OpenStack?

First off you need juju and charm-tools, ensure you have the latest stable juju:

sudo apt install juju-core

Then you need to provide your OpenStack credentials files to Juju, assuming it's named credentials.yaml:

juju add-cloud <cloud name> <cloud definition file>

References:

Official Docs


DNS server does not listen on IPv6 after a reboot

I was having the same issue, and attempted to modify the named "bind" scripts in 20.04 LTS to no avail. I then changed my thinking, and then found the solution to delay the named service startup via the system and found an article via ASK.
Not sure why the ipv6 subsystems and network interfaces take so long to initialize.
The solution I am using is I added a line to the /lib/systemd/system/named.service file
in the service stanza like this. "Inserted the line just under the stanza heading".
[Service]
ExecStartPre=-/bin/sleep 10
This seems to be the best way to solve this issue, so you don't have to muck with the startup scripts as those will change as packages get updated over time.
I am running some Acer laptops with the latest I5 gen 9 processors, on top of an SSD drive and it boots so fast, I also have other race conditions with peripheral hardware interfaces and firewall startup scripts that can be solved the same way.
Hope this helps!


What is the difference between add-apt-repository & apt-add-repository?

They're the same command, someone just added the inverse because people kept mixing the command up and typing it wrong.


Your command is almost correct. Use

 tar cvfzp achive.tar.gz --exclude notthisfolder thisfolder/

Note that the --exclude notthisfolder option goes after the archive name.
Cosmetic comment: when using the z option, you are using gzip to compress your tarball, so name the archive archive.tar.gz and not archive.tar.
Also, /thisfolder/ is an absolute path and points to the folder thisfolder inside the root directory /. For specifying a relative path (to the current working directory), use thisfolder/ without the leading slash /.
As a little tidbit, you don't need to prefix the cvfzp options with a -. One less character to type!

Works for me ;)

$ tree
.
└── thisfolder
    ├── butincludethisfolder
    │   ├── includefile1
    │   └── includefile2
    ├── file1
    ├── file2
    └── notthisfolder
        └── notthisfile

3 directories, 6 files

$ tar cvfzp achive.tar.gz --exclude notthisfolder thisfolder/
thisfolder/
thisfolder/butincludethisfolder/
thisfolder/butincludethisfolder/includefile1
thisfolder/butincludethisfolder/includefile2
thisfolder/file1
thisfolder/file2


To make a bootable Windows USB disk on Ubuntu, I would recommend using WoeUSB. To install it, use the commands:

sudo add-apt-repository ppa:nilarimogard/webupd8
sudo apt update
sudo apt install woeusb

Format your USB drive as NTFS (open your files, secondary-click on the USB drive, click "Format", and select "Type" as "NTFS").

Open WoeUSB, select the Windows ISO file, and select the USB drive. Click "Install". This might take a while. When it's finished, you should see "Installation succeeded!".

You now have a bootable Windows USB drive.


First add the repository then you can upgrade the VLC:

sudo add-apt-repository ppa:videolan/master-daily
sudo apt-get update
sudo apt-get install vlc


isc-dhcp-server stops working after ubuntu-desktop is installed

I was experiencing the same problem with my Mint 18.3 (Ubuntu 16.04). These are two things that helped to solve it in my case:

Remove all empty lines and spaces at the end of the files /etc/network/interface , /etc/dhcp/dhcpd.conf and /etc/default/isc-dhcp-server
Add manually the ip to your wireless interface:
ifconfig wlp2s0:0 10.255.0.1 netmask 255.255.0.0 up

Check with ifconfig that the ip has been correctly added to your device. Then restart network manager and isc-dhcp-server and see that everything works. Reboot and check that the ip of the device is still set.

Note: if you are using hostapd after all that and you get an error like:

nl80211: Could not configure driver mode
nl80211 driver initialization failed.
wlp2s0 (o el que sea): interface state UNITIALIZED - DISABLED
wlp2s0: AP-DISABLED
hostapd_free_hapd_data: Interface wlp2s0 wasn't started

You have to edit /etc/NetworkManager/NetworkManager.conf
Add the following entry where the x's are replaced with your WiFi MAC address, save, and then reboot:

[keyfile]
unmanaged-devices=mac:xx:xx:xx:xx:xx:xx

Sources:
Set static IP Ubuntu 16.04

hostapd error "nl80211: Could not configure driver mode"

https://www.garron.me/en/linux/add-secondary-ip-linux.html


Lightning Extension Not Showing Reminders When Opening Thunderbird

Not sure if i understand the question but in about config there is 2 settings for snooze /edit/preferences/advanced/about:config

`mail.spam.markAsNotJunkMarksUnRead;true

 calendar.alarms.defaultsnoozelength;5

and when you add or edit an event or task hit the reminder buttom and set the alarm.
hope it helps


TL;DR
Join #ubuntu on freenode or join us in the Ask Ubuntu chat.

Ubuntu (and Linux in general) uses IRC for support and collaboration quite extensively. If you're not familiar with IRC take a look at this beginners guide. The #ubuntu channel is where ubuntu support happens, and where you will want to ask your questions.
You'll need an IRC client. I recommend hexchat which you can install with the command:
sudo apt-get install hexchat

When you open it, hexchat will ask you to input several usernames (in case your first choice is already taken):

Input a few usernames (or use the populated ones), select "Ubuntu Servers (freenode)" from the networks list and click "connect".

You're in! Now join the #ubuntu channel by typing:
/join #ubuntu

and pressing enter. Ask your question! Be detailed and show your research. Don't be a help vampire.


Is there any battery management software to work with a laptop plugged to AC power so as to save the battery lifetime?

The reason why batteries are not removable as much anymore cause they do not work like they used to. Batteries these days do not over charge so by removing the battery you are not doing anything. The best thing is to not let the battery run under 5% and this is what will maximize your battery life cycle.


Ubuntu virtualbox guest doesn't see sound card

Try to check the VM Settings in VirtualBox. Right click on the VM (when it's shut down), click Settings, and check the Audio section. Make sure the Audio is Enabled, and to choose ALSA as the Host Audio driver .

This should work.


How to rollback an apt-get upgrade from command line?

You can display packages that are going to be upgraded and version changes with:

sudo apt-get update
sudo apt-get -V upgrade

The '-V' flag shows you the additional info. As for the snapshots - you really have to roll your own here.

My favourite method for having the rollback ability is using LVM with snapshots on Linux - but the last time I checked, there was no progress on the automated rollback to the chosen snapshot. This might have changed since then (I'd be happy for someone to correct me), but you can always boot using root=/dev/vg0/root-snap kernel parameter (for instance) and then use rsync to sync the snapshot /dev/vg0/root-snap to the original volume /dev/vg0/root and then discard the snapshot. Not ideal but can be automated.

Of course ZFS snapshots rock but there's no official, production-ready ZFS support for Linux (yes, I'm aware of zfsonlinux.org and ZFS-FUSE), so unless you're just playing around, that's not really a feasible option for you.

UPDATE: it looks that we can now rollback (merge in LVM2 parlance) snapshots. So the update would take the following form with LVM2:

Create a 5GB snapshot of your root LV:

lvcreate -s /dev/vg0/root -L5G -n root-snap
Update the package (as above).
Roll back if necessary by running:

lvconvert --merge /dev/vg0/root-snap

And because /dev/vg0/root (the original LV) is opened, lvconvert will notify you that the /dev/vg0/root will be rolled back to /dev/vg0/root-snap upon the next activation of this volume. This happens when you run

lvchange -ay /dev/vg0/root

while this LV is closed, which is upon the next boot or after running:

lvchange -an /dev/vg0/root


If you are dual booting, just boot into Windows instead.

If you are not, you will need to (re-)install Windows.  Simply insert the Windows Installation CD, and follow the instructions.  Beyond that, this is an Ubuntu website, so we can't provide any help with the windows installation process.


I can't get ubuntu to recognize my wifi card

See this answer

For kernel 4.15 you need this:

sudo dkms remove rtl8723de/5.1.1.8_21285.20171026_COEX20170111-1414 --all
sudo apt update
sudo apt install git dkms
git clone https://github.com/smlinux/rtl8723de.git -b 4.15-up
cd rtl8723de
sudo dkms add .
source dkms.conf
sudo dkms install $PACKAGE_NAME/$PACKAGE_VERSION


Network connection lost ('carrier-changed')

After removing other factors, such as the switch, the problem continued.

I asked one of the system administrators of our organisation's network and he seems to think that such an error message means that there is a physical problem with the network.

For example, with the switch gone, this means:

cable from the computer to the port
port itself
even the cabling behind the port, within the wall

In any case, he said it is "definitely" not related to the OS but was unable to decipher the error message piece-by-piece.  So, this is where the problem stands and I'll be looking at the physical connection to the computer instead of Ubuntu.


How to retrive back your Ubuntu files after a crash even after Live Ubuntu Boot is not working

The space that I presume once contained your Ubuntu installation (51.86 GiB) shows unallocated.  That means that partition has been deleted.  Officially, everything in it is gone.  The one you're trying to mount, /sda4, is the extended partition that contains the logical volumes that once held your Ubuntu and still hold its swap.  It was never mountable.

Unofficially, you may still be able to recover the contents, if you can create a new partition with exactly the same parameters as the one that used to be there.  However, you'll then be in the position of having partitions out of order on the hard disk, which is also bad -- and you can't just delete the swap partition, because it's holding the space that might let you recreate the missing partition.

What I would attempt is to create a new partition (it'll be assigned /sda6) in the empty space before /sda5, and then delete /sda5.  Later, you may be able to recreate the swap (it'll now be designated /sda7).  DO NOT format the new /sda6 partition when you create it, but be sure you use the same filesystem type you had before (be that ext4, ntfs, btrfs, or whatever else).  Also, check the box to make the partition bootable.

After you've done all this, restart on your Live USB and see if you can mount the new sda6; if so, you will then be able to correct GRUB and the /etc/fstab in that partition to point to the correct partition (UUID will have changed, even if you're using that method).

IFF everything has gone well to this point, you'll be back where you were before your Windows quit working, with (at least) the data in your /home recoverable (you'll probably still need to reinstall Ubunbtu to undo the crash that started all of this).

There's no guarantee this will work -- I've recovered contents by recreating a deleted partition, but I did it under DOS 3.31 with fdisk, when that was a current operating system.  I've never tried it since.  On the other hand, it won't make things any worse than they are now.


Unable to save images by dragging and dropping them from browser to Nautilus or desktop

Dragging the image onto the desktop/nautilus, pressing Ctrl (and dragging a bit more) before dropping saves a copy.


Can Wubi 12.10 installation be overwritten, but retain the wireless configuration?

When re-installing Ubuntu, configuration files are lost. You have to back up your wireless setup. Please check:

http://ubuntuforums.org/showthread.php?t=1218483

or similar posts that are about the location of the files.

As for Wine I suggest you uninstall it and install PlayOnLinux instead. POL should install a working version of Wine.


I had the same problem.
My setup is intel(internal video) + nvidia gtx860(external + primary video) and 2 monitor(internal + external).

Workaround is to remove the file "~/.config/monitors.xml" in terminal execute command:

rm ~/.config/monitors.xml

Reconfigure you monitor setup after reboot/relogin, configuration file will recreated.

May be it would be helpful.

But, after secondary reboot/relogin problem will returned....


Do I have to set up the BIOS on a new HDD/SSD? If so, how?

The BIOS ("Basic Input Output System") is every computer's built-in firmware.

It's located on a small Flash or EEPROM chip directly on your mainboard. Normally this chip is not removable nowadays.

Its purpose is to start booting the computer and initialize all the hardware so far that it can hand over the control to your operating system's boot loader (e.g. GRUB for Ubuntu), which is stored on one of your hard disks.

That means you normally don't have to worry about the BIOS. You can't lose it, especially not from changing a HDD.


Google Chrome not using Ubuntu's Titlebar and Window Buttons

Launch Google Chrome and go to Settings from the hamburger menu (three horizontal bars/dots at top right). Then under Appearance select Use GTK+ theme

Also turn on the Use system title bar and borders option.

If it doesn't work right away, reboot your system once.


Edit the first line of the script from #!/bin/sh to #!/bin/bash, if you get the error, gzip: stdin: unexpected end of file when running the script.
Instead of running the script, you could also try adding the printer just using the provided PPD file.

Download the appropriate PPD file (pos58.ppd)

Plug in your device (USB)

Open CUPS web interface.

Addminstration -> 'Add printer'

Under 'Local Printers', you should see your printer. The generic
printers usually are displayed as 'Unknown'

Choose the PPD file from your disk.

Finally click on 'Add Printer'


Read man 2 chmod. The interpreter has to be able to Read the script, as well as knowing the script is executable. Usually, I have my scripts set to 755 or 555.


UEFI install UBUNTU 14.04 Along Windows 8 (Dual Boot)

First you could try to restore the bootloader by using this live cd: http://sourceforge.net/projects/boot-repair-cd/
If that doesn't work, the non complicated order would be:
1. Install Windows
2. Install Ubuntu
The GRUB bootloader detects other OS at install.
Also make sure if you are installing from USB make sure the bootloader doesn't get installed on your USB stick. Happend to me already several times.
More info here: https://help.ubuntu.com/community/WindowsDualBoot


For a simple installer flash drive that will boot in UEFI

Insert flash drive, note it's location, likely sdb.
Download Ubuntu ISO file, cd to it's directory.
Run in terminal:

sudo dd if=isofilename.iso of=/dev/sdb

(assuming sdb is the USB)

Process will take a while.
When done boot Ubuntu from USB flash drive in UEFI mode and install.


This thread grub-recordfail-broken-regarding-lvm tries to get to the bottom of the problem.

If you are looking for a quick fix, you can

sudo sh -c 'echo GRUB_RECORDFAIL_TIMEOUT=5 >> /etc/default/grub';
sudo update-grub;

thank @borislav for pointing out sudo grub-install; is not needed for configuring Grub menu timeout


The greeter ignores users with UIDs of under 1000, so when you changed your user's UID to less than that, it disappeared. I personally recommend that you fix it by putting its UID back. If you can't do that, How to make users with UID under 1000 appear in LightDM? gives some ways that apparently will let you show it anyway.


How can I change the number of password entry attempts allowed by sudo?

This is documented in man sudoers. The setting you are looking for is:

 passwd_tries      The number of tries a user gets to enter his/her pass‐
                   word before sudo logs the failure and exits.  The
                   default is 3.

So, to change that to, for example, 5, run sudo visudo and add these lines:

## Allow a user to attempt to enter a password 5 times
Defaults        passwd_tries=5

As far as I know, there is no way to set it to unlimited times but you can simply use a huge number:

Defaults        passwd_tries=99999999

That is unlimited for all intents and purposes, unless you have a user with a very severe case of OCD, they won't attempt to enter a password more than 100 million times.


Are there drawbacks to not wanting to upgrade your Ubuntu anymore?

Ubuntu 11.04 is supported until October 2012. Until then, you will continue to receive stability and security updates. After that time though, support will be dropped, and if new security vulnerabilities are discovered, for example, you won't be covered. It's fine to stay with 11.04 during the duration of the support period, but after that you should start considering upgrading to a newer release, or switching distros / desktop environments if you can't learn to adjust to Unity or GNOME Shell by then.


Upgraded to Ubuntu 14.10 and *everything* lags

I have a new carbon. I had slow redrawing of windows and other problems, although no particular problem with video. Fixed with: https://wiki.archlinux.org/index.php/Intel_graphics#SNA_issues

If you are experience issues with SNA, try using UXA instead, which can be done by creating an X configuration file containing the following:

/etc/X11/xorg.conf.d/20-intel.conf

Section "Device"
   Identifier  "Intel Graphics"
   Driver      "intel"
   Option      "AccelMethod"  "uxa"
EndSection

EDIT: DO NOT USE THIS SOLUTION. SNA has been fixed. Upgrade your kernel (at least 4.0 probably) and video card drivers (>=2.99.917 i think) instead.


Grub don't work after latest Win10 update

I was using the wrong file in bcdedit command. The right command is:

bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi


Ubuntu Steam and Windows Steam are not the same software.

The only way to do that =from the official download= is to install the same OS on the  machine you can download it onto and install Steam on there. Then you can copy the install over to your home machine with the same OS.

Easiest (Muru disagrees :P) method would be:

install virtualbox
install Windows in virtualbox
install steam into Windows
copy the steam folder + registry key(s) over to your home system.


It really depends on your usage patterns. Newer versions of Ubuntu typically mean: newer kernels, newer versions of unity, newer versions of the tools in the repository.

From a "conservative" point of view, you might prefer to avoid upgrades. If your system is running fine (for you); and you do not need newer versions of a certain tool - there is not much gain in moving forward. Although there is only a small chance for upgrades to fail and cause damage to your system - it is still possible; therefore: "if it is not broken, dont fix it".

The important fact is that you should understand when a version of Ubuntu runs out of support - after that, there won't be security updates, ...

The other dimension is: some people just like to run "latest-greatest". This means that you might enjoy newer features earlier than other users - but it can also mean that you have to deal with bugs that other users do not see.


I now installed Microsoft Windows Compatibility Layer (meta-package) and Dashlane works like a charm!


It seems the problem is caused by specific albums. I don't know why these albums are crashing Rhythmbox, but I am removing them as I find them.

Any suggestions as to how I can investigate the issue further?


Install Ubuntu10.04 on LVM :: error: no such disk

I have solved this problem. I went to my BIOS and disabled the floppy. It now works!


It does not exist any list with all modules. Some modules are just blacklisted because they make trouble on certain hardware. Sometimes it is easy to get the reasons by googling. However most of the time it is almost impossible.


How to pernamently disable Caps Lock in Lubuntu?

setxkbmap -option caps:none disables Caps Lock. To make it pernament it is necessary to add this command to autostart.

To do this in Lubuntu go to start menu, select "Preferences", run "Default Applications for LXSession". Then go to tab "Autostart" and add this command using "Manual autostarted application".

It disables Caps Lock on login, unfortunately it is not disabling Caps Lock on entering username and password on logging in.

Answer based on http://www.howtogeek.com/194705/how-to-disable-or-reassign-the-caps-lock-key-on-any-operating-system/


`service` no longer gives useful output (except with status) in 15.04?

At the very least,something like a script and an alias would probably do the trick, here...

Maybe:

#!/bin/sh
# service-status
service "$1" "$2"
if [[ $2 != "status ]]; then
    service "$1" status
fi

Or better yet; since service is really systemctl anyway:

#!/bin/sh
# service-status
systemctl "$2" "$1"
if [[ $1 != "status" ]]; then
    systemctl status "$1"
fi

and then add this to your .bashrc or your .bash_aliases:

alias service="service-status";


Installed FULL Ubuntu on USB, boots up, but not on other computers

An installed system is portable between computers, but not as portable as a live or persistent live system. Things to check:

Avoid proprietary drivers.
Usually an installed system will work either in UEFI mode or BIOS mode, not both. But it is possible to make a system that can boot in both modes, as described in this link.
Check that the system is compatible with the computer hardware. 32-bit Ubuntu works in both 32-bit and 64-bit hardware, but 64-bit Ubuntu needs 64-bit hardware.
Check that the bootloader was installed in the USB drive (and not in the internal drive), as suggested in the comment by @C.S.Cameron.

The following link and links from it can give you several tips that help you make a portable Ubuntu system, that will work in the computers, where you want to run it.

Boot Ubuntu from external drive


Why isn't adding a path to ".profile" working?

To add a system-wide path, simply add to the PATH variable defined in /etc/environment.

Press Alt+F2 and type gksudo gedit /etc/environment
Change the default path:

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"

by adding your path to it:

PATH:"/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/treedev/lib/Qt/bin"

To add this path only to your session (i.e. for your user only), add to ~/.pam_environment instead:

PATH=$PATH:/home/treedev/lib/Qt/bin

  Related: Please see the Ubuntu Wiki on Environment Variables.


How do I replace a file in an ISO file without needing root from the command line

I finally managed to find an answer myself. I can use fuse to mount the ISO file, there is even a tool for this in the Ubuntu repositories:

sudo apt-get install fuseiso

Then I can do:

fuseiso -p file.iso mounted_iso/
rsync -ra mounted_iso/ copy/
fusermount -u mounted_iso

chmod -R +w copy/
edit copy/file

mkisofs <many options> -o remastered.iso copy/


A folder and a file with the same name in the same location

The OS and file system do not allow this

Ubuntu and its file systems (ext3, ext4, etc.) doesn't allow an identically named file and folder in the same directory.

Therefore, nautilus does not allow renaming a folder to an existing file name.

However, Ubuntu (GNU/Linux in general) file systems are case sensitive. You can have a folder called Articles and a file called articles in the same location. Note the folder name starts with a capital A, while the file name starts with a small a.

You can use any CaPiTaLiZaTion conventions you want for your folders and files.

An alternative

An alternative is to create a file called index.html inside each folder where you want the folder and the file to have the same name. Naming your HTML file index.html and putting them in a folder called e.g. example.com/articles/title, so the full path is example.com/articles/title/index.html, will also accomplish what you're asking.

When one types https://example.com/articles/title the web server will serve the index.html page and browsers won't show the index.html. It will show only https://example.com/articles/title.

Similarly, you can have a file called https://example.com/article/index.htmlto show what you want when one types https://example.com/article.

Thanks to Harry for the alternative and some other points.


What is "normal" activity on the loopback (lo) network interface?

As soulsource already pointed out, you're probably looking at interprocess communication done over the localhost network. That isn't very efficient, but in programming this is sometimes useful to have a single piece of code whether the two components are running on the same machine or over the network. Let's have a look how to track this down.

As your tcpdump shows it's sending data to port 8332 on localhost, you can see what's listening there using netstat:

sudo netstat -nlptu | grep 8332

(-n for numeric output, -l for listening sockets, -p to show the process, -t and -u to show both TCP and UDP sockets.)

You should see something like

tcp   0      0 127.0.0.1:8332   0.0.0.0:*   LISTEN     21891/SomeProcessName

Then investigate this process ID further:

ps u --pid 21891

This will show something like

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
gert     21891  0.0  0.0 480768 13836 ?        Sl   13:49   0:11 /path/to/some/binary

There.

  How does the loopback interface affect networking performance? Can I pretty much ignore it when trying to figure out my wifi problem?

This has nothing to do with the performance over other network interface cards. I suggest to ask a new question for that.


Installing windows on the /dev/sda5 ntfs partition would not tamper with the performance of Ubuntu.It doesn't cause any damages to your preinstalled Ubuntu Os.

After installing windows on dev/sda5,don't forget to run boot-repair.


Is there a way to prevent USB over ethernet from working?

I think usbguard could be a good fit for you. Looking at device class ids, rules would be like:

block with-interface equals { 02:*:* }
block with-interface equals { 0A:*:* }
block with-interface equals { E0:*:* }
allow

Of course, you can also be more specific, build a whitelist instead, etc. You may also want to whitelist your Bluetooth device. The package has examples; there is also an applet.

A "pure udev" way may also exist.


usb mp3 player not showing up using ubuntu 16.04

The device doesn't seem to work correctly with usb 3.0 ports but works ok with usb 2.0 ports


It probably doesn't need that much RAM.

If I write a program that opens a file with a random filename, writes "Hi there, Moon!", and closes that file cleanly, and repeats that a couple of million times, It would use very little memory, but will take a lot of time.


Wifi not working on Ubuntu 16.04 ACER Aspire E14

It appears that you need firmware! Please try, with a working internet connection:

sudo apt-get update
sudo apt-get install linux-firmware

Reboot. Is it working? If not, please check:

sudo dpkg -s linux-firmware

We hope we see that the installed version is 1.157.13. If not, try:

cd /tmp
wget http://mirrors.kernel.org/ubuntu/pool/main/l/linux-firmware/linux-firmware_1.157.13_all.deb
sudo dpkg -i linux-firmware*.deb

Reboot. Is it working?

EDIT: I suspect that the download was somehow corrupted. Let’s try again:

cd /tmp
rm -rf linux-firmware*
wget http://mirrors.kernel.org/ubuntu/pool/main/l/linux-firmware/linux-firmware_1.157.13_all.deb
ls -al

We hope the size is 44364698. If so, let’s install it:

sudo dpkg -i linux-firmware_1.157.13_all.deb

If the size of the downloaded package is different, stop and post the size.

Please post any errors or warnings.


You are doing it wrong. It is technically possible to boot Linux from folder, but it would require GRUB or Shellx64 preinstalled and involves low-level fiddling with files (and many tools to use). From the way you ask the question I assume you lack the skill by far.

So, don't bother with it now. Just download ISO image and add it to Virtualbox machine (when you create new virtual machine, it even prompts you on first launch to provide OS ISO)


Switch to virtual console x (x ≥ 8) (CtrlAltFx, say x = 12). Those don't have getty or LightDM (or anything, really) running on them, so the cat can walk over the keyboard to its heart's content. Then press CtrlAltF7 to get back to LightDM and the login screen.

You could automate this during boot by adding chvt 12 to /etc/rc.local (see this U&L post).

Special buttons like the power button might still be a cause for concern.

On second thought, other key combinations are available:

if the virtual console is not running X, then the CtrlAltFx can be used without Ctrl - just AltFx would work.

Alt+ arrow keys can also be used to switch to the previous and next VTs
CtrlAltDel triggers a reboot in any of the VTs not running X.

So a better solution might be running an empty X session (not running any other application) in VT12 to cut down the number of available key combinations and switching to it.

startx -- :100 vt12 &
chvt12

This needs to be tested (you might need to write an .xinitrc to override the defaults).


maybe this bug affecting nvidia users
https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/1166765

try the temp fix - open a terminal    and execute the following:

$ gsettings reset org.compiz.core:/org/compiz/profiles/unity/plugins/core/ active-plugins
$ shutdown -r now

fixes it but maybe not permanently yet so keep this note handy.


Can I boot Ubuntu Mobile OS without fully wiping my phone?

Generally for non-Nexus devices, that's a no. There are no official images or semi offical ports with such functionality.

The least invasive installation was a DualBoot installation released for the Nexus 4. It consisted basically of:

A custom recovery image used to boot Ubuntu
"The data partition contains the Ubuntu system under /data/ubuntu/"

So the installer script would set this up for you and you could still use your Android without wiping. It may still work with recent combinations of Ubuntu and Android releases, but I havent testet this as I sold my Nexus 4.


I have installed Firefox 50.0.2 but it is not available through the Dash

I suggest you just stick to normal packaged versions of Firefox, and don't install from independently downloaded tarballs.

Press Ctrl-Alt-T to open a terminal
Run sudo apt-get update (updates the package list on your machine)
Run sudo apt-get upgrade (fetches and installs new versions of your software)

I checked and I can see that Firefox 50.0.2 should be available using the above approach on 14.04 (source).

If you want a nice graphical interface for installing software, try sudo apt-get install synaptic, then you will have a program called Synaptic that will be accessible from the Ubuntu menu, allowing easy installation of the latest-available versions of a wide range of packages.


Script does not empty trash containing .deb files

Either a permissions issue, or there aren't any .deb files to empty. Not sure why you'd even need a script to empty the trash, unless you're deleting thousands of files an hour, when you can just click "empty trash".


copy directory tar.gz file from root to external hard disk error

Do not try to write to a device file (/dev/sdxY) - you should write to the mount point (/media/username/drive_name)

Since your trying to copy as root you should be doing:

cp -av dspace_tar.gz /media/username/external_hdd_name

If you don't know the mount point of the device, first plug it in then do this to get the address:

lsblk -f

The options:

-f option provided more information about the filesystems.
-a : used when copying archives
-v : displays the process in the terminal


Hello follow the guide manual guide in https://github.com/horst3180/arc-theme
I was having the same problem but its solved now.


Suspend problems - Chromebook running 12.04.1 LTS

I discovered that touching the track pad while in suspend will cause the machine to start back up.

I also discovered that pressing on the machine in the touchpad area while the machine is closed causes the touchpad to be 'touched'.  This is likely why your machine comes out of your bag in an active state.  It was for me, in any case.


3TB non-boot hard disk on older motherboard

You should have no problems -- at least in theory. Motherboard compatibility isn't really an issue; once the computer is booted, the Linux kernel is in charge of things, so the issues involved (hard disk size and partitioning method) must be resolved by the Linux kernel, not by the computer's firmware. The Linux kernel has long supported both large hard disks and GPT. If you dual boot with Windows, though, there are potential hazards, since some Windows drivers use 32-bit pointers, which will end up trashing data on over-2TiB disks.

In fact, the old BIOS firmware doesn't explicitly support any partitioning system, not even the Master Boot Record (MBR) system used on most BIOS computers. Thus, lack of GUID Partition Table (GPT) support in BIOS isn't an issue, even if you wanted to boot from the disk. (There are some caveats and limitations, but I won't get into those since they'd just be a digression, given that you don't plan to boot from the disk.)


How to remap a key when it's pressed twice?

Set aliases for characters, strings or complete lines

UNLESS you are using wayland (Ubuntu 17.10, tested on Ubuntu Budgie 18.04, but Ubuntu Gnome 18.04 should be fine too), the snippet below will help you out.

How it works in practice

Press Ctrl + J (or any other shortcut you set)
A box appears

Type your "alias" (e.g. jj for m), the result shows (m), and the text will immediately be inserted at cursor position (or, if you prefer, after tapping Ctrl).

This script provides a single solution to set aliasses for a character, a string or even complete lines, just set the "alias" in the lines:

replacements = [
    ["jj", "m"],
    ["aa", "q"],
    ["zz", "e"],
    ["mb", "monkey eats banana"],
]

In the latter case, typing "mb" will paste "monkey eats banana":

Setting up

You need to satisfy a few dependencies:

pyautogui:

pip3 install pyautogui

pyperclip:

sudo apt install python3-pyperclip xsel xclip

python3-xlib

sudo apt install python3-xlib

Log out and back in.
Copy the script below into an empty file, save it as replace_keys.py

#!/usr/bin/env python3
import gi
gi.require_version("Gtk", "3.0")
gi.require_version("Wnck", "3.0")
from gi.repository import Gtk, Gdk, Wnck
import subprocess
import pyperclip
import pyautogui
import time

"""
depends on
- pyautogui:
  pip3 install pyautogui
- pyperclip:
  sudo apt install python3-pyperclip xsel xclip
"""

act_on_firstmatch = False

replacements = [
    ["jj", "m"],
    ["aa", "q"],
    ["zz", "e"],
    ["mb", "monkey eats banana"],
]

class KeyWin(Gtk.Window):

    def __init__(self):

        self.screendata = Wnck.Screen.get_default()
        self.screendata.force_update()
        self.curr_subject = self.screendata.get_active_window().get_xid()
        self.currmatch = ""
        Gtk.Window.__init__(self)
        maingrid = Gtk.Grid()
        self.add(maingrid)
        self.set_decorated(False)
        self.set_position(Gtk.WindowPosition.CENTER)
        self.connect("key-release-event", self.check_key)
        self.keyentry = Gtk.Entry()
        self.keyentry.connect("changed", self.update_current)
        self.label = Gtk.Label("")
        self.label.set_width_chars(10)
        maingrid.attach(self.keyentry, 0, 0, 1, 1)
        maingrid.attach(self.label, 1, 0, 1, 1)
        self.show_all()
        self.connect("destroy", Gtk.main_quit)
        Gtk.main()

    def update_current(self, widget):
        curr = self.keyentry.get_text()
        self.currmatch = ""
        for s in replacements:
            if curr == s[0]:
                self.currmatch = s[1]
                if act_on_firstmatch:
                    self.replace()
        self.label.set_width_chars(len(self.currmatch) + 4)
        self.label.set_text(self.currmatch)

    def replace(self, *args):
        pyperclip.copy(self.currmatch)

        subprocess.call(["wmctrl", "-ia", str(self.curr_subject)])
        Gtk.main_quit()

    def check_key(self, button, val):
        typed = Gdk.keyval_name(val.keyval)
        if typed == "Control_L":
            self.replace()

KeyWin()
time.sleep(0.05)
pyautogui.hotkey('ctrl', 'v')

Set up your aliasses (KEEP THE INDENTATION!) in the section:

replacements = [
    ["jj", "m"],
    ["aa", "q"],
    ["zz", "e"],
    ["mb", "monkey eats banana"],
]

If you want, change

act_on_firstmatch = False

into

act_on_firstmatch = True

if you like to insert immediately without tapping Ctrl
Set up a shortcut key with Ctrl as modifier. I used Ctrl + J in my test to run the script by the command:

python3 /path/to/replace_keys.py

And you're done!


Xampp PHP File Permissions with NTFS Hdd's as additional media storage

First of all: you don't have to reformat anything.

I'd suggest the following setup for your fstab entries:

UUID=X /media/<path> ntfs-3g uid=<your username>,gid=<a group containing www-data>,umask=007 0 0

umask=007 sets the permissions to rwx (read, write, execute) for both group(www-data) and user (you).


How to enable Qt Creator 3.2.2 to use GDB?

As explained in this blogpost, default1 install of GDB in Ubuntu appears to be gdb-minimal. To get a version of GDB usable with Qt Creator, you can just do

sudo apt-get install gdb

which will remove gdb-minimal, install gdb and additionally install libc6-dbg. After this you'll be able to debug your project using QtCreator without getting such errors.

1I'm not sure in what sense it is the default, maybe it's installed with build-essential, or something else...