How do you return a list of the current project folders and files of your current project in QtCreator?

You can list the files in a given directory with QDir::entryList().  QDir has a number of other methods that may be useful for you as well.


This has happened to me before.
I just made another live usb with a new iso freshly downloaded from the internet
as said in the other answer set the boot sequence to usb-hdd.
Also some usb's are not bootable or broken i have found this out when asking this to a IT technician


I haven't tried PPTP (and see no reason to - it's utterly broken security-wise), but I have tried OpenVPN and that works just fine.

They have a fairly detailed tutorial listing the steps required, step by step, including all commands. I suggest you follow that - I have used it for configuring VyprVPN connections a few times, and had no problems with it.


Installation incomplete of mysql-server-8.0 in Kubuntu 20.04

It is the password.
I had the same issue and solved it yesterday, as well on a Kubuntu 20.04 and MySQL-Server 8.0.
Since you have already tried a few things, you have some errors in the system, these must be fixed first.
Now you have to uninstall the MySQL server completely.
su root
systemctl stop mysql.service
systemctl disable mysql.service
systemctl stop avahi-daemon.service
systemctl stop avahi-daemon.socket
apt autoclean
apt clean

If installed, also remove php and phpmyadmin. If not skip this step.
apt remove --purge phpmyadmin
apt remove --purge php-*

Watch the uninstall log, look for warnings and error messages.

dpkg: warning: while removing php7.4-cli, directory '/etc/php/7.4' not
empty so not removed

rm -rf /etc/php/7.4

Continue
apt remove --purge mysql*
dpkg --configure -a
apt autoremove
rm -rf /etc/mysql /var/opt/mssql /usr/bin/mysql /usr/share/mysql /usr/share/man/man1/mysql.1.gz

This command will delete the MySQL user and all associated files, therefore the disk will be completely scanned for MySQL user data and depending on the speed, size and occupancy this may take longer. Unmount all other disks.
deluser --remove-all-files --force mysql

At this point you will get an warning message.

Removing files ...
Removing user mysql ...
Warning: group mysql has no more members.
Done.

Check if the group mysql is removed.
cat /etc/passwd | grep mysql
cat /etc/group | grep mysql

Should be without resultet, empty.
Now reboot the system
reboot

Next reinstall the MySql-Server
su root
apt update --fix-missing && apt --fix-broken install && apt full-upgrade && apt autoremove
apt install php
apt install php-mysql
apt install mysql-server
mysql_secure_installation

Use a password with at least 8 characters, of which at least one must be an uppercase letter, one a lowercase letter, one a number and one a special character.
Not all special characters are allowed, but there is no error message if you enter a wrong character and that's the problem.
Use these: ( )
Example password: H4CkM31Fy()Uc4n

password validation police


pclean is just a wrapper for pbuilder --clean, and from the manpage of pbuilder:

--clean
      Cleans   up   the   directory  specified  by  the  configuration
      BUILDPLACE and APTCACHE specified in /etc/pbuilderrc


Check out the wiki for the latest touch FAQ here


GTK-Message and warnings in Ubuntu 14.04

The Message lines mean you are missing the overlay-scrollbar-gtk2 and unity-gtk2-module packages.

The WARNING is because you are apparently missing the gtk2-engines-murrine package.


There are several linux live systems for repair or rescue purposes. See for example this link,

Top 5 Linux System Rescue CDs

I have tried

The Ultimate Boot CD (current version 5.3.8 fits on a standard CD disk)
System Rescue CD (current version 6.0.2 too big for standard CD disk)

but I think the other alternatives are also worth trying.

Rescatux (current version 0.51b3 fits on a standard CD disk)
Tiny Rescue Kit (current version TRK 3.4 build 372 fits on a standard CD disk; from 2011, could fit old computers, might fail to repair new versions of file systems or bootloaders)

You can also use a small enough 'regular' linux distro for this purpose, depending on whether the tool that you need is available, for example

Tiny Core
Puppy linux (there are several versions and flavours).

Knoppix is a powerful alternative for a rescue and all-round live system, if you need not squeeze the live system into a CD.

There are current Knoppix DVD size iso files to be burned to DVD disks or cloned to USB pendrives (now at version 8.2 dated 2018-05-10)
There are also Knoppix CDs, but the newest version, that I can find, is getting old (version 7.2 dated 2013-06-16)

But if you need not squeeze the live system into a CD, please consider using your Ubuntu iso file (burned to a DVD disk or cloned to a USB pendrive) for repair or rescue of the installed system.


It appears that the issue was caused by the rutilt wireless pacakge.  Removing it resolved the issue.  I'm currently trying to determine whether Lubuntu installed the package -- I already have the standard Ubuntu wireless tools in place, and they work whether or not the Error in question appears, and with or without rutilt.


Apply the proc/acpi/wakeup settings permanently

The preferred way to do this is by creating a service with systemd.
Adding script in rc.local is the deprecated way.

Create a script file wherever you wish. Ex: ~/Scripts/disable-devices-as-wakeup.sh.

#!/bin/bash

declare -a devices=("EHC1 EHC2 XHCI") # <-- Add your entries here
for device in "${devices[@]}"; do
    if grep -qw ^$device.*enabled /proc/acpi/wakeup; then
        sudo sh -c "echo $device > /proc/acpi/wakeup"
    fi
done

Test it by executing it from the terminal.

If everything is okay then let's make a service.

$ touch ~/Scripts/disable-devices-as-wakeup.service

$ chmod u+x ~/Scripts/disable-devices-as-wakeup.service

~/Scripts/disable-devices-as-wakeup.service -
[Unit]
Description=Disable devices as wakeup

[Service]
ExecStart=/home/username/Scripts/disable-devices-as-wakeup.sh
Type=oneshot

[Install]
WantedBy=multi-user.target

Copy paste or move the service to /etc/systemd/system/.

$ sudo cp ~/Scripts/disable-devices-as-wakeup.service /etc/systemd/system/

Enable the service.

$ systemctl enable disable-devices-as-wakeup.service

Restart the OS and check the status.

$ systemctl status disable-devices-as-wakeup.service

Detailed explanation found on https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/chap-managing_services_with_systemd


chromium-browser cannot cast desktop to chromecast, immediately disconnects

After some more digging, I found this reddit post and it actually has a solution: In chromium use

three-dot-menu -> settings
search for 'accel' and disable 'Use hardware acceleration when available'.


you can try below listed method On start press:

Ctrl + Alt + F1

then type 'startx' (without quotes)


How to get a list of running programs in Lubuntu 14.04?

It is called "Task Manager" in Lubuntu.

If you want it from commandline: top and htop.
From their wiki:

LXTask is the standard task manager and system monitor of LXDE. It starts via Ctrl+Alt+Del and is extremely lightweight.
To remove an unresponsive application, you may use Term or Kill. It is recommended to first try Term, to see if the application can respond.


How do I remove diskdigger completely from my computer?

Enter the following commands to completely delete DiskDigger and everything asociated from it's install, based on, and as per Running DiskDigger in Linux. The 1st part completely removes (purges) the packages for Windows Forms 4.0 for Mono you needed to run it.

sudo apt-get purge libmono-system-windows-forms4* libmono-system-design*
sudo apt autoremove
rm diskdigger.zip
rm DiskDigger.exe


Sometimes, you need to add the command in your configuration including all the parameters.

I had the same issue. Adding xrandr --output DVI-I-2 --mode 1920x1080 --rate 144.00, where you of course have to identify your parameters by just running xrandr and setting your DVI/HDMI output correctly.


Cannot recover "Trashed" files in 13.04 64 bit

You should try restoring again with the external drive plugged in. Files in the "Trash" are stored inside a hidden ".Trash" folder at the root of each external drive you plug in. Much the same way the "Recycle Bin" works on windows.


Unknown display on Dell Inspiron 7000, Ubuntu 20.04.1

12/01/2021. Exact and detailed steps I followed to solve the problem (note there may be unnecessary steps, but it's the best I can do given my expertise).
First, I found out prime-select query outputs the current setting for display, in this case nvidia or intel. Switching to intel (or nvidia) is possible with sudo prime-select intel (or sudo prime-select nvidia). After selecting intel and rebooting, the problem persisted.
Second, I read Peter's notes. Did some careful reading - mind! I did not follow his instructions from Ubuntu installation -, particularly the seven steps just above "Install NVIDIA driver" which I replicate here for redundancy:
"
1. Open the terminal.
2. Type sudo gedit /etc/default/grub .
3. Change the line GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nouveau.modeset=0" .
4. Press “Save” and close the window.
5. In the terminal, type sudo update-grub2 .
6. Reboot.
7. Select Ubuntu.
If you want to boot into Ubuntu, you can add either nomodeset or nouveau.modeset=0 in the boot option. However you cannot adjust the screen brightness if you use the former one. And remember, only nomodeset works for installing Ubuntu. Using nouveau.modeset=0 for the installation boot will fail.
" (Peter Pang, 2018). Reboot and problem persists.
Third, I followed the author's advice to install tlp and powertop to improve battery life. Reboot and seemed fans didn't spin as fast as before. At this point, try rebooting few times and it might solve the problem (I suspect the above might be enough).
Fourth, I went on and started to follow steps by yatritrivedi to create a shared NTFS partition, I input the following in this order:
sudo apt-get install ntfs-3g,sudo mkdir /media/storage,sudo mkdir /mnt/storage,sudo cp /etc/fstab /etc/fstab.backup,sudo cp /etc/fstab.backup /etc/fstab,sudo blkid,reboot.
With an screen fixed to 2560x1600, I had it set to 200% scaling (big letters and icons) but for some reason the log in screen always appeared with 100% scaling. This time after reboot, login screen appeared at 200% scaling as well, which gave me hope something had changed.
Pressed the brightness button in keyboard and it worked! Went to Settings > Screen Display and voilà! I have a "Built-in Display" and a couple dozens of resolutions to choose from. I left the resolution as it was, activated fractional scaling and adjusted to 150%.
This solved it for me and hope it helps anyone else with same or similar problems.
P.S. Time to look at the sound problem.


How to make ALT+TAB switcher icons smaller

As far as I know...the size of the default "Switcher View (Alt+Tab)" is hardcoded in the Unity source. You can try to edit the source code to change the size according to your needs.

NOTE: I recommend you to do this in a Virtual Machine or in a Test Machine to see if you get the desired results.In this example I'm running Ubuntu 13.04 with unity 7.0.0 and I will change the "Switcher View" (icons, tiles, etc.) to the half-size.

1) Make sure you have enable the Source code repository.

Open the Ubuntu Software Center
In the Menu Bar choose Edit -> Software Sources. Click to enable "Source code repository".
Just in case I use the "Main Server" to Download.

Open a Terminal window Ctrl+Alt+T and type:

sudo apt-get update

2) In the Terminal type the following to install the necessary packages.

sudo apt-get install build-essential python-windowmocker quilt

3) Install build dependencies.

sudo apt-get build-dep unity

4) Create a folder to download the source code.

mkdir ~/Downloads/src

cd ~/Downloads/src

5) Download the source code & Export variables.

apt-get source unity

export QUILT_PATCHES=debian/patches

export EDITOR=gedit

6) Create the patch and Edit the source code.

cd unity-7.0.0daily13.06.19~13.04/

quilt new 99-custon-switcher-size.patch

quilt edit launcher/SwitcherView.cpp

Edit the lines... 46 to 50.

I changed them from:
  , border_size(50)
  , flat_spacing(20)
  , icon_size(128)
  , minimum_spacing(10)
  , tile_size(150)

To:
  , border_size(25)
  , flat_spacing(10)
  , icon_size(64)
  , minimum_spacing(10)
  , tile_size(75)

7) Build the deb packages.

quilt refresh
fakeroot dpkg-buildpackage

8) Install the deb packages.

cd ..

sudo dpkg -i *deb

9) Finally you can Restart your machine to see the changes.
Before:

After:

Hope this helps.


You need to install the ubuntu restricted formats package...

sudo apt-get install ubuntu-restricted-extras

But you can use "Movies" to play the MP3. That piece of software automatically scans for plugins.

mp3:

mp4:


How to get gnome-screensaver-command info passed along to the script called by CRONTAB

SOLVED:
Using Notify-send doesn't work from crontab
NEED TO SET DBUS:
Using the gnome-session first results pid for DBUS_SESSION_BUS_ADDRESS lookup:
source /home/experiment/.bashrc
pid=$(pgrep -u experiment gnome-session | head -n 1)
dbus=$(grep -z DBUS_SESSION_BUS_ADDRESS /proc/$pid/environ | sed 's/DBUS_SESSION_BUS_ADDRESS=//' )
export DBUS_SESSION_BUS_ADDRESS=$dbus
export HOME=/home/experiment
export DISPLAY=:0
export USER=experiment

if (gnome-screensaver-command -q | grep "is active"); then
    echo $(date) :::: $USER :::: Active>> $HOME/crondate.txt
    uu="user: $USER   date: $(date)   screensaver: ACTIVE"
elif (gnome-screensaver-command -q | grep "is inactive"); then
    echo $(date) :::: $USER :::: InActive>> $HOME/crondate.txt
    uu="user: $USER   date: $(date)   screensaver: INACTIVE"
else
    echo $(date) :::: $USER :::: N/A>> $HOME/crondate.txt
    uu="user: $USER   date: $(date)   screensaver: N/A"
fi


How to grep line ONLY before and above of my line?

I tried to find for several hours, but as always it was so simple:

grep --color=always -Irn 'foo' -A1 -B1 | grep -In --color=always "bar" -A2 -B1

Finding 'foo' and 1 line after '-A1' and 1 line before '-B1', pass this to second grep and process with keyword 'bar' and voilà!
-I is for ignoring binaries, -r means recursive search and -n means output line number.
--color=always - highlights matched string.


Differences between ubuntu 14.04.1 LTS and 14.10?

The most important aspect is what you are looking for.
For myself, I am looking for a stable platform that I can do my job on. Since my job is really unrelated to Linux or Linux Development, I picked LTS, which stands for Long Term Support. I want a platform that I know they will keep providing security and critical bug fixes. So I always pick the LTS versions.

If you pick 14.10, or future non LTS version, you will get the latest and greatest features, but you will also be required to upgrade your entire system more often.

Take a look at the Table of Versions to understand what you are in for.


Print multiple variable of an ID into single line with IDs and its single variable in a line?


upgrade to 13.10 stalled and restart failed

If you can boot:
If you want to try to upgrade via the command line, try the instructions here
In a nutshell, run
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

to update all packages, then
sudo apt-get install update-manager-core
sudo do-release-upgrade

to do the actual update to 13.10
Otherwise,
Get your files out (using a Live USB/CD)
and reinstall from a 13.10 Live USB/CD.


This drove me crazy.  Make sure Pulse Audio Volume Control is installed.
To install open a terminal (Ctrl+T) and type sudo apt-get install pavucontrol

This took me forever to find but worked like a charm.


How can I configure Juju for deployment on OS X?

Using Juju to Deploy Your Rails Application is a great place to start. That documents what you need to do to deploy a rails application with Juju.

For development purposes, the Juju Vagrant Workflow for OS X will get you up and running with a Vagrant virtual machine in order to fully experience Juju using the local provider. This is how I do most of my development work.

When you're ready to put your application live, you would then use your own private cloud or a public one such as Amazon.

For example, I'd write a yaml file to tell the Rails charm about my rail application. Next, I'd fire up a Vagrant virtual machine, which will start me with a fully functional local environment to test with. I'd deploy rails, passing it the yaml file I created, and then test to verify that my application works as expected.

At that point, I'd shut down the vm, returning to my OS X terminal, and juju switch amazon, juju bootstrap the environment, and then deploy the application.

That's all a bit high level, but should point you in the right direction.


How to extract a record in a text on string match in a file using bash

#!/bin/bash

tr '\n' ' ' < sample.txt | sed 's:=====:\n=====:g' | sed 's: *$::g' >tmp1

grep "author:john" tmp1 | sed 's: :\n\t:g' > test1.txt
grep "author:paul" tmp1 | sed 's: :\n\t:g' > test2.txt

rm tmp1

the "tr" command replaces every newline for a space (the whole file is now 1 line)
this gets piped to "sed" which will cause every "=====" to start on a new line.
The second "sed" will delete trailing spaces.  This all is send into a temporary file. You now have 1 "record" per line.

The first "grep" will read from the temporary file and output all the records where "author" is "john", these records are piped into "sed" which replaces every space with a newline-followed-by-tab (to exactly reproduce the OP's layout) and send this to a file named test1.txt

The second grep idem for "paul" and "test2.txt"

Last action is deleting the temporary file which is no longer needed,


Welcome to Ubuntu!

Ubuntu (and Debian + its derivates) uses .deb package, which could be considered as equivalent to windows .exe file.

If you want to install software manually without internet connection, you can download .deb files from Ubuntu repository
http://packages.ubuntu.com/

First, choose your distribution (I assume you are running 16.04 LTS = Xenial), pick what package do you need and download it according to your architecture (32b or 64b)

When you have your file downloaded, install it by either double-clicking, which will open Software center, from where you can confirm installation, or, if you are interested in more sophisticated way, you can open terminal  Ctrl+alt+t and type:

cd "name_of_directory_where_you_put_the_file"

sudo dpkg -i "nameofthepackage.deb"

It may eventually happen, that you won't be able to install some package due to the missing dependencies. This is difficult to fix without the Internet connection for the new user, tho. But you can use the error output and look for the packages stated as missing.

Good luck and if you had any questions, feel free to ask in comments, or by editing your question, eventually by creating new one.


New 14.04 LTS install fails to boot with purple screen

The section "Black/purple screen after you boot Ubuntu for the first time" from My computer boots to a black screen, what options do I have to fix it? helped. Installed NVIDIA drivers and now working.


you could try to add the following to your grub script

insmod all_video

(or invoke from the grub prompt)...

Although to TBH that didn't work for me.

I'm trying to figure out grub2 myself...I'll let you know if I figure this one out.


-f, --fix-broken
         Fix; attempt to correct a system with broken dependencies in place.
         This option, when used with install/remove, can omit any packages
         to permit APT to deduce a likely solution. If packages are
         specified, these have to completely correct the problem. The option
         is sometimes necessary when running APT for the first time; APT
         itself does not allow broken package dependencies to exist on a
         system. It is possible that a system's dependency structure can be
         so corrupt as to require manual intervention (which usually means
         using dpkg --remove to eliminate some of the offending packages).
         Use of this option together with -m may produce an error in some
         situations. Configuration Item: APT::Get::Fix-Broken.

Running the command:

sudo apt-get install -f

Should repair any broken dependencies.


problem in setting up amd dual graphics Trinity [Radeon HD 7660G] and Thames [Radeon HD 7500M/7600M Series]

I'd check to see if there is anything in the xorg.conf file and if not use:

sudo aticonfig --initial -f --adapter=all

It might be picky about aticonfig vs. amdconfig.

Restart and check BIOS to make sure the cards are enabled. When loading, if the screen freezes on the load screen hit Alt + Ctrl + F2, login and type:

sudo nano /etc/X11/xorg.conf

To see if both GPUs are now in the config file. If they are still not there, you can put your second GPU in there manually by using the info provided by:

lspci | grep -i vga

Just write or copy and paste a second copy of what is in xorg.conf below what is there and replace the details in the second copy with the info about your other GPU, i.e 01:00.0, and Default 1

If it's a bad install and it says fglrx doesn't exist, then go to:

http://wiki.cchtml.com/index.php/Ubuntu_Saucy_Installation_Guide

and make sure to do a for sure uninstall  and then download all of the prereqs. and install again.

https://help.ubuntu.com/community/BinaryDriverHowto/AMD is also an awesome resource. I would suggest bookmarking them two links, and reading everything.

aticonfig --help

is cool too.

The little reply box is not cool

per the cchtml website,
Force use of the new xorg.conf (if necessary)

  Some people find that changes to xorg.conf don't get used by the
  driver. To force the ATI driver to adopt changes made to xorg.conf,
  use the following command:

  sudo amdconfig --input=/etc/X11/xorg.conf --tls=1

I have used that before, in 12.04, and since 12.04.4, it seems harder to set up the proprietary drivers. I got mine set up, but it was a pain. I can do dual-gpus, but I have to set my BIOS to default GPU, and auto Integrated. But, I have a APU and a GPU, not two actual GPUS, so maybe that is harder to set up in bios?


CIFS mounting fails in Ubuntu 13.10 tried with sec=ntlm and sec=ntlmv2

I have had this problem on various networks which needed samba filesharing services from an Ubuntu or LinuxMint-based file server.

In every  case, while the user's samba account had a password and allowed browsing (and manipulating files) of a share through a file manager, fstab mounts did not work.

This is regardless of having set sec=ntlm or sec=ntlmv2 or sec=ntlmssp or any of the various other options typically offered as a "solution" (i.e. such as setting the file_mode or user or gid)

In every case the solution for our installations has ended up being the same: reset the samba user's password and the mount works, regardless of setting options!

I'm not sure what happens when the password is "inherited/converted" from the user's Linux account, but there seems to be a significant problem there, notwithstanding the ability to browse (not mount) a samba share.

I am now going to cross post this reply to a couple similar AskUbuntu posts which promote the same "answers" which often do not seem to help those with problems.

Perhaps this approach will help you with your fstab samba mounting challenge.  I hope so and good luck.


How can I make Synergy accommodate the dead space around dual monitors?

I would try using ranges. (I'm estimating that the amount of left to right spread that is the right monitor is 60 percent. Starting at 40% from the left and extending to 100%.)

Notice the black space? That part counts. That's why I say to put it 40% in instead of 0% to 100%. Try this first one.

section: links
    Desktop:
        down(40,100) = Laptop
    Laptop:
        up = Desktop(40,100)
end

So far, this is the best that I think it can do. I tried to figure out a way you could move from Desktop-Monitor1 or monitor 2, but I just ended up only being able to leave the right side of monitor 2, not monitor one. Same problem trying to make it so that you can leave Lappy and move left onto D1 - you end up arriving on D2


We can use apt new patterns. Use man apt-patterns for more info.

List all packages which their names contains "fonts" and count them:
$ apt list '~n.*fonts.*' 2> /dev/null | wc -l

573

Filter out the output using grep to look for fonts-mathematica:
$ apt list '~n.*fonts.*' 2> /dev/null | grep -i mathematica

fonts-mathematica/focal 21 all
mathematica-fonts/focal 21 all

To exclude it:
$ apt list '~n.*fonts.* !?exact-name(fonts-mathematica)' 2> /dev/null |
grep mathematica

mathematica-fonts/focal 21 all

Or even to exclude both of them:
$ apt list \
'~n.*fonts.* !?exact-name(fonts-mathematica) !?exact-name(mathematica-fonts)' |
 grep mathematica

So here is what you are looking for:
$ sudo apt install \
'~n.*fonts.* !?exact-name(fonts-mathematica) !?exact-name(mathematica-fonts)'

And it would definitely end up with a lots of conflicts.
What we can do is to generate a list of all these packages:
$ apt list \
'~n.*fonts.* !?exact-name(fonts-mathematica) !?exact-name(mathematica-fonts)' |
cut -f1 -d/ > 2>/dev/null fonts_lists

Or even in a cleaner way:
$ apt-cache search --names-only fonts | grep -v -e fonts-mathematica -e mathematica-fonts | cut -f1 -d' ' > fonts_list

Then use a guide like this: "Continue on error when apt-get encounters an install unable to locate package issue" to install them one by one.


Type xrandr in Terminal for the refresh rate if that's what you want.


Do any NetworkManager VPN plugins support IPv6?

IPv6 over the VPNs in NetworkManager is not currently supported in 12.04 and prior releases of Ubuntu. It is a new feature introduced in a further release of NetworkManager (0.9.6.0), so it will be available, to begin with, on the OpenConnect plugin only. Such support will be available in Quantal Quetzal (Ubuntu 12.10).


Mathcad does not have a version for Ubuntu, but Wine is a program that makes it possible to run many Windows programs on Ubuntu. You can install Wine through the Ubuntu Software Center. (By the way, feel free to ask if you need help getting things set up in Wine.) Mathcad 11 appears to work pretty well through Wine (see here); animations may not work, though. Mathcad 14 might work well through wine (see here). Either version appears to need some tweaking to get running.

If it won't work through Wine (or its versions like the commercially-supported CrossOver Linux), then I don't know of another way to get that specific program to work in Ubuntu.

There may, however, be acceptable replacements on Ubuntu. This blog post refers to SMath Studio as a "free Mathcad alternative for Windows, Linux and Windows Mobile". It doesn't look like it is packaged for Ubuntu, but you can install it by following these instructions. I've included a screenshot of SMath Studio below.

SMath Studio


Samba - Error while copying , invalid argument

You have created a share for your web folder.  For security, the files are usually only writable by the owner.  The default group and owner is www-data.

You will have to change the folder's permission to either allow anyone in the world to write to it, or change the permission so that the group can write to it and add the samba userID to the www-data group.

The world writable is very insecure, unless the share is a public access where you want the world to be able to make changes to the folder (the world as in anyone with login access to your system).  The latter (adding the samba account to the www-data group is more secure if the account would only be shared with trusted users.

There are other alternatives such as changing the group and owner of folder to a different user/group such as the userID given to the samba account of the logged in user.


WIll I be able to upgrade the developer preview to the full version?

There are and will be frequent updates of the Ubuntu Touch Developer Preview. See here: The latest as I write this is from March 23, that's the same day. So time by time more functions will be added and the developer will get a better and more complete basis system in order to test their applications and to test the whole system.

This is an imminent prerequisite for the application developer therfore it would not make sense for canonical to continue working on the system somewhere behind closed doors and finally come out with a final release.

So at the end the Developer Preview will be the final release or at least very similar to that.


The actual package name may contain some suffix (less probably a prefix, too), try searching for packages beginning with the string texstudio:

apt list --installed 'texstudio*'

Then remove the found package(s), e.g.:

sudo apt remove texstudio-qt4


Try sudo update-grub in a terminal. That might help.


Most of them are system daemons and can't actually log in, they
  represent processes started by the init system.  If you look at
  cat /etc/passwd, you'll see them all listed.  The last field is the
  default shell, which may be /sbin/nologin or /bin/false indicating
  their lack of login possibilities.  The forth field (each field is
  separated by an :) is a comment that may provide some information
  about their purpose (for more, see man 5 passwd, the 5 is important,
  otherwise you'll get the section 1 passwd command; section numbers
  are described in man man).

  Daemon services1run in the background, often as
  unprivileged users for security purposes -- this way undiscovered
  vulnerabilities can't be used to gain root access, etc.   Some of them
  use the generic daemon user, others create their own for more secure
  compartmentalization.

  For example, Avahi is one such daemon, for broadcast and discovery of
  network services (e.g. certain kinds of file sharing, I believe) on a
  LAN.  NTP is another, for synchronizing the system clock with a WWW
  reference server.  On Ubuntu, services such as this can be
  enabled/disabled via upstart (an init system developed by
  Canonical).

  nobody is a catch-all account for things intended to operate with no
  privileges beyond just existing.

  1.  The "Notable service daemons in Unix-like systems"
  section of that wikipedia article contains some things from your
  list.

Source


USB stick modem stopped connecting after upgrade to 11.10

I had the exact same problem with my rogers nokia usb stick, I got mine working by disabling the ubuntu control over WLAN and downloading the linux driver from the nokia website, it did give me some warnings when installing the driver but it works.


SSH connected remote server is using my local computer's internet

Your server's upload speed to an imaginary ultra-fast server is 300 Mbit/s

Your local connection's download speed from an imaginary ultra-fast server is 120kbps (>2000 times slower).

The 120kbps is the limiting factor when you download from your server to your local PC. Your server may be capable of pushing 300 Mbit/s to another fast server but this doesn't mean that it will be able to do the same through the slower connection to your local PC.


Create Live DVD/USB from already installed Ubuntu 18.04

Why not just install Ubuntu 18.04 on, for example, a USB drive and then you can use something like Clonezilla to create an image with only the used blocks. It will come out quite large but there are few other options left.


Can Ubuntu split the desktop across two graphics cards?

This should work fine, though I can't vouch for the stability of NVIDIA on Ubuntu. If you need another monitor, get an AMD card for it.

As long as your computer has the physical capacity for another PCI-E video card, you should be perfectly fine, and Ubuntu should recognize the second card and third monitor without a problem. Go ahead and get a video card when you need it and just make a new question if you have trouble getting it working.


How can I get my keyboard to load sooner?

It turns out my keyboard works in two ports, but only one of them will give me access to bios. I inadvertently figured this out by having both keyboards plugged in at the same time.  At least that seems to be what happened, either way, thanks a lot for the help.


Ubuntu 18.04.1 - TP-LINK UE330 Ver: 2.0 driver problem

Try this...

In terminal...

cd /etc/netplan                       # change directory

sudo cp 01-netcfg.yaml 01-netcfg.HOLD # backup the file

sudo pico 01-netcfg.yaml              # edit the file

replace what you see there with this...

Note: if you copy/paste this text, remove the 4 spaces at the beginning of each line...

 # This file describes the network interfaces available on your system
    # For more information, see netplan(5).
    network:
      version: 2
      renderer: networkd
      ethernets:
        enp19s0:
          dhcp4: yes
          optional: true
        enx503eaa8b183c:
          dhcp4: yes
          optional: true

then...

sudo netplan --debug generate # generate the config files

sudo netplan apply            # apply the new configuration

reboot                        # reboot the system

review the previous lshw and ifconfig commands to check operation.


Enter key does not execute command in python and bash

The problem was caused by my ~/.inputrc that I hadn't checked: I had accidentally mapped the return key to a history-search-backward action: removing the line in question solved the issue


kernel: wlan0: deauthenticating from x by local choice (reason=3)

None of those kills wpa_supplicant (oddly enough: If I unload all wifi modules and disable wifi you would think wpa_supplicant would take the hint). So:

sudo killall wpa_supplicant

and then everything works.


How to install AR5523 chipset wifi in Ubuntu 12.04?

From here

Install this package, depending on the version of ubuntu you may have:

12.04 (precise pangolin): https://launchpad.net/~medigeek/+archive/experimental/+files/ar5523-source_0%7Eslh.12%7Eppap1_all.deb

11.10 (oneiric ocelot): https://launchpad.net/~medigeek/+archive/experimental/+files/ar5523-source_0%7Eslh.12%7Eppao1_all.deb

11.04 (natty narwhal): https://launchpad.net/~medigeek/+archive/experimental/+files/ar5523-source_0%7Eslh.12%7Eppan1_all.deb

Execute the following commands, copy-paste them one by one:

sudo apt-get update
sudo apt-get -f install
sudo apt-get upgrade
sudo apt-get install build-essential linux-headers-generic module-assistant
sudo m-a a-i ar5523-source
wget http://verein.lst.de/~hch/ar5523.tgz
tar xvf ar5523.tgz ar5523/uath-ar5523.bin --strip 1
sudo mv uath-ar5523.bin /lib/firmware


What is the replacement for -n switch in Aptitude in 13.04?

I never heard of such option, I suppose you are thinkin of the ~n search term (Search Term Reference), used as

aptitude purge ~nxfce4

or equivalently

aptitude purge '?name(xfce4)'


Printing StackExchange pages with Firefox is slow on Ubuntu, but not on Windows; why?

I think I found the culprit:

in printing options (in Firefox), disable

print background colours
print background images

Often, these aren't necessary, cost toner (thereby impair one's environmental footprint!), and seem to - for certain pages - massively slow down the printing process(ing).

see also (for general reference)

https://support.mozilla.org/en-US/questions/940802

https://support.mozilla.org/en-US/kb/fix-printing-problems-firefox

https://support.mozilla.org/en-US/kb/how-print-websites?s=print&r=0&e=es&as=s


But even with everything closed, the zero used session still shows 2 GB RAM consumption is system load indicator . . . I want to know whether this a normal thing or I should be worried about my hardware. Thanks.

I think this is normal because my system also has the same memory usage. I currently have nothing running and my memory use is 2.0 GB, cache 1.8 GB but I also have 4 GB of swap space (2 GB swapfile and 2 GB zram) and my swappiness is set to 10.

I use zram along with regular swap, on 4GB of RAM, with an SSD instead of a hard drive on a Toshiba laptop with an old-generation i3 processor from ~2012 and things run smoothly.

  How to find out how much swap space I have ?

Use swapon to find out how much swap space you have.

  Should I increase it ? If yes, how to do that ?

I do not recommend you increase the size of your swap file but I do recommend using zram to increase your overall swap size.

Using zram will automatically add 1/2 of your RAM size to your swap size without the diminishing returns of a swapfile (HDD access is about 10³ slower then RAM access).

To increase your swap space using zram, you can run the following commands:

sudo apt update
sudo apt install zram-config
sudo systemctl enable zram-config
sudo systemctl start zram-config

To verify that zram is in use, run: swapon and zram should be listed.

Here is an example:

~$ swapon
NAME       TYPE        SIZE   USED PRIO
/swapfile  file          2G 101.9M   -2
/dev/zram0 partition 486.1M 209.3M    5
/dev/zram1 partition 486.1M 210.1M    5
/dev/zram2 partition 486.1M 208.6M    5
/dev/zram3 partition 486.1M 206.8M    5


What's a bitmap:

A mdadm bitmap, also called a "write intent bitmap", is a mechanism to speed up RAID rebuilds after an unclean shutdown or after removing and re-adding a disk.

With a bitmap, writing data to the RAID goes like this:

Update bitmap: Mark the RAID chunks you are about to write to as dirty.
Write the data to the RAID.
Update bitmap: Mark the RAID chunks that were just written as clean.

The advantage of a bitmap is that if the system goes down in the middle of a write, the rebuild needs to check only the chunks marked as dirty, rather than the whole multi-TB RAID. This can speed up the rebuild process from taking several hours to completing in just a few seconds.

The drawback is lower write performance under normal use (outside rebuilds), since mdadm does additional disk access to update the bitmap.

External vs internal:

external: Stored as a file on a disk outside the RAID. The advantage over an internal bitmap is better write performance during normal use (outside rebuilds).
internal: Stored as RAID metadata. The advantage over an external bitmap is that you don't need a non-RAID disk and you save a bit on configuration (the path to the bitmap).

According to the mdadm man page:

Note:  external bitmaps are only known to work on ext2 and ext3.
       Storing bitmap files on other filesystems may result in  serious
       problems.

According to a post by Neil Brown, the mdadm author, external bitmaps should work on ext4 too:

I haven't looked inside ext4 but I am fairly confident that external bitmaps
will work properly.

HOWTO:

Bitmaps are added and removed using mdadm --grow --bitmap=XXX ..., where the XXX is one of:

--bitmap=internal: Create an internal bitmap.
--bitmap=/var/my_bitmap.bin: Create an external bitmap at the specified path. The path must reside outside the RAID. A bitmap=... parameter must be added to the ARRAY entry in /etc/mdadm/mdadm.conf, and the --bitmap=... parameter must be passed if you are assembling the RAID from the command line.
--bitmap=none: Remove/disable any bitmaps.

References:

HowTo: Speed Up Linux Software Raid Building And Re-syncing
mdadm man page - see flag -b, --bitmap=
mdadm.conf man page - see option bitmap

Comments:

IMO, bitmaps are perhaps primarily of interest for RAID levels 5 and 6, since these have the slowest rebuilds.

I switched from RAID 5 to RAID 10 myself; the rebuilds are so much faster that I don't feel the need for a bitmap, and RAID 10 seems to require far fewer rebuilds in the first place.

My RAID 5 setup used to drop a disk something like once a month, causing 12-14 hour rebuilds. The RAID 10 has only dropped a disk once in half a year, rebuilt in less than an hour.

I don't know if the frequent disk drops I experienced was caused by something other than the RAID level, but the RAID 10 has been far more stable and rebuild speed isn't much of a concern anymore.


https://help.ubuntu.com/community/Lubuntu/Mouse#Touchpad_settings is the Lubuntu Documentation on touchpad settings.  Open a terminal and enter synclient -l  That will give you the current touchpad settings.  Scroll down to the MaxTapTime.  It probably says MaxTapTime = 180 or some other number.  To disable tap to click according to the Lubuntu documentation enter synclient MaxTapTime=0.


How can I reinitialize ssh-agent through a remote login after rebooting?

Activating ssh-agent as if through the Xsession but remotely remains beyond my grasp but I think using this is a superior option: https://github.com/ccontavalli/ssh-ident/blob/master/ssh-ident

Swapping that in to wrap ssh causes it to handle all of the agent setup automatically and keep it set up persistently, I just need to enter my key once per reboot and it's off to the races.


Install dosbox
Download word55_en.exe from http://www.bttr-software.de/freesoft/txtedit1.htm (bottom the page)
Run downloaded exe (from dosbox): unpack install files
Run setup.exe (to install word55)
Run word.exe
Ready


So, I'm not sure what the original problem was, and I'm not entirely sure how my pad is mapped.

That said, I found an interesting work-around here:

https://wiki.archlinux.org/index.php/Touchpad_Synaptics#Buttonless_TouchPads_.28aka_ClickPads.29

It mentioned changing some options within /etc/X11/xorg.conf.d/10-synaptics.conf, but that directory doesn't seem to exist for me.  It suggested changing certain values for the percentage of the click-pad to be dedicated to a given button, and then it suggested checking certain parameters within synclient -l.  I wound up just manually editing the parameters to match.  The boundaries do not seem to match perfectly with the lines marked on my click-pad, but those are completely arbitrary.  The differences could be resolved by trial and error if it became an issue, I suppose.

Shift+F10 still does not work, but I have since learned that right-click was simply mapped elsewhere.  I don't know where to find the default settings for that particular shortcut; it is not included in the list shown by holding down Super.  However, I have learned that it was mapped by default to a button between my right alt and ctrl keys.  The key resembles the usual menu, with one bar highlighted.  This probably won't be relevant to many folks on non-HP machines.

Thanks, everyone, for taking the time to work with me.


The standard Ubuntu NVidia drivers generate some problems on slightly older and slightly newer NVidia hardware.

If you want more then the standard Ubuntu repository drivers, install the xorg.edgers PPA.  As the xorg.edgers group ask not to give installation instructions directly without linking to their page, this is the best I can do for now...

If you don't know what a PPA is or need some guidance about rolling forward and backward of driver versions  after reading their page, leave a comment below.


Script to edit program launch command in terminal

You can use autofs for doing some sort of it. autofs will only mount a certain path if you access it.

Therefore you could configure Rhythmbox do scan your library on that path. It is not exactly what you said but it fits.

Other even simpler option could be mount your Windows partition on boot time (I would go with it because it is the easiest way but I have assumed that you don't want to do it).

Check autofs at community wiki.


Ubuntu 12.10 Skype webcam microphone not working

Solved with pavucontrol. I had already tried the pulseaudio volume control, but you need to do a particular thing to make it work.

First, install pavucontrol:

sudo apt-get install pavucontrol

Then start it:

pavucontrol

You'll get the volume control window. Now, you could go to "Input devices" and select the webcam microphone as your input source: THIS WON'T WORK. This is how you do have to it:

Click on the "Recording" tab. This tab shows the applications that are capturing audio in that very moment, so it will probably be empty.
Start skype then call the Echo / Sound Test Service (or anyone you like who will answer)
When the other party answers, Skype begins capturing audio and will be shown in the "Recording" tab of the pulseaudio volume control window
From the "Input from" drop down list, select your webcam

And voilà, you'll get your microphone back.

Alternatively, as described in SkypeTroubleshooting

[..] go into the Skype Options menu - Sound Devices
remove the tick at: Allow Skype to automatically adjust my mixer levels.
Click Apply.
Readjust the sound mixer controls (pavucontrol input devices will work now).

This worked fine for me.


Press shift and  then F6 when you see the little man and install with "nomodeset"
The first time you run Ubuntu after installation you will need to enter recovery mode (press escape during boot) and update grub.

This sort of problem should not be in an LTS version of Ubuntu


pycurl.error: (35, 'gnutls_handshake() failed: Handshake failed')

I was sincerely hoping that this could be resolved without following some instructions which I hardly understand and compiling things and so on. But unfortunately...

See this Gist from 2014 for instructions.

At the time of writing, using Ubuntu Trusty 14.04.2 LTS, the versions are still the same, namely 7.19.3, so the instructions in the Gist can be followed one by one. Spot check was ok and also curl is still working with https://. After stepping through the recipe, pycurl.version shows

PycURL/7.19.3 libcurl/7.35.0 OpenSSL/1.0.1f zlib/1.2.8 libidn/1.28 librtmp/2.3

To automate the downloading, patching and compiling, you will love this little script:

#!/bin/bash

#
#   How to rebuild PycURL against OpenSSL on Ubuntu
#   (tested for 14.04.2 now)
#
#   This script implements the great Gist by aerickson:
#   https://gist.github.com/aerickson/f15133a7e56b2d7f27e3
#   feel free to use it anyway you like.
#   Credits go to Andrew anyway :)
#

# we will add some colored headers that make it easier to find obstacles
# in the terminal output (which will be > 1000 lines...)
ESC="\x1b["
RESET=$ESC"39;49;00m"
RED=$ESC"31;01m"
GREEN=$ESC"32;01m"
YELLOW=$ESC"33;01m"
BLUE=$ESC"34;01m"

header() {
    echo -e "\n$YELLOW --- $1 --- $RESET\n"
}

echo -e "\n\n$GREEN"
echo -e "\
Build pycurl with openssl support\n\n\
Section numbers refer to\n\
https://gist.github.com/aerickson/f15133a7e56b2d7f27e3
"
echo -e "$RESET\n"

# remove eventually existing pycurl
header "0. remove python-pycurl"
sudo apt-get remove python-pycurl --yes

header "1. install build essentials"
sudo apt-get install build-essential fakeroot dpkg-dev --yes

header "2./3. make build dir"
mkdir ~/python-pycurl-openssl
cd ~/python-pycurl-openssl

if [ ! "$HOME/python-pycurl-openssl" = `pwd` ]; then
    echo -e "\n${RED}Cannot change to working dir. WTF?${RESET}\n"
    exit 1
fi

header "4. get pycurl sources"
sudo apt-get source python-pycurl --yes

header "5. get build dependencies for python-pycurl"
sudo apt-get build-dep python-pycurl --yes

header "6. install libcurl with openssl"
sudo apt-get install libcurl4-openssl-dev --yes

DIR=`find * -name 'pycurl*' -type d -print`
DSC=`find * -name '*.dsc' -type f -print`

echo
echo "DIR = $DIR"
echo "DSC = $DSC"
echo

header "7. unpack source archive"
sudo dpkg-source -x $DSC

header "8. change to package dir"
cd $DIR

header "9. edit debian/control file"
sudo cp debian/control ./control.gnutls
sudo cat ./control.gnutls | sed -e 's|libcurl4-gnutls-dev|libcurl4-openssl-dev|' | sudo tee ./control.openssl >/dev/null
sudo cp ./control.openssl debian/control

header "10. build package"
echo "hold on..."
echo "(crashdump of nosetests is 'normal')"
sudo PYCURL_SSL_LIBRARY=openssl dpkg-buildpackage -rfakeroot -b 2>&1 | sudo tee ../buildlog.txt >/dev/null
echo
echo -e $BLUE
sudo head ../buildlog.txt
echo -e $RESET
echo "   [ ... 1000+ more messages omitted ... ]"
echo -e $BLUE
sudo tail ../buildlog.txt
echo -e $RESET
echo
echo "find more output in ~/python-pycurl-openssl/buildlog.txt:"
wc -l  ../buildlog.txt

header "11. install via package manager"
sudo dpkg -i ../python-pycurl_*.deb

echo
echo "some other packages are available also now:"
ls ../*.deb
echo "they can be installed by 'sudo dpkg -i ../py...' from here."

There is hope, however, that a newer version 7.19.5 will make it to the repos, which is supposed to have the issues fixed in GnuTLS so that PycURL would start to work out of the box. Still the question remains, why this issue is in the repos since 2009 and no one cares...

Update Issues

Funny enough, any subsequent regular Ubuntu update of pycurl/libcurl will overwrite your change. So be prepared to repeat this over and over :(

Alternatively, you can put python-pycurl on hold after building it with openssl to make sure apt-get update will not overwrite it anymore:

sudo apt-mark hold python-pycurl

Updates can be re-enabled later by

sudo apt-mark unhold python-pycurl

Raspberry Recipe

The above script runs fine on Raspberry Pi with Raspbian Wheezy too, when you add the ability to install sources before by

sudo nano /etc/apt/sources.list

and uncommenting the deb-src line, so that the file will look like

deb http://mirrordirector.raspbian.org/raspbian/ wheezy main contrib non-free rpi
# Uncomment line below then 'apt-get update' to enable 'apt-get source'
deb-src http://archive.raspbian.org/raspbian/ wheezy main contrib non-free rpi

When the sources are not found (in step 4), you might have to do an

sudo apt-get update

before running the above script.

Note: On the Raspberry, the process suffers a bit from the processor speed and you should take aside half an hour (if everything works smoothly). And again, either you put python-pycurl on hold or you will have to invest this half hour again after each update.


How can I drag and drop files into the Ubuntu One bookmark in Nautilus?

You can get a similar result (where by “similar” I interpret “gives you a way to drag things into the Ubuntu One folder from Nautilus) in one of four ways: add an extra pane (press F3, or View → Extra Pane),

switch to having a tree in the sidebar (View → Sidebar → Tree),

add an extra tab (Ctrl+T, or File → New Tab),

or simply open a new nautilus window (Ctrl+N, or File → New Window).


Why mouse always move to left-top corner of screen

Try forbidden your touchpad,Always a notebook encounter this problem----emmm,is when your touchpad has broken.[My English isn't good,sorry.


What is the building photographed in this stock wallpaper?

It is the Walt Disney Concert hall in Los Angeles, designed by Frank Gehry.

From the photographer's site: http://edltphoto.com/2010/09/ubuntu-blue/

  My photo of a portion of the Walt
  Disney Concert hall in Downtown Los
  Angeles.

A full sized picture of the concert hall is included below, a description is found here


It should work under Ubuntu and use the ar5523 kernel module for wifi.  I checked the kernel for your device and got

modprobe -c | grep -i 3a08
alias usb:v07D1p3A08ddcdscdpiciscipin ar5523


Have you see VMware Player should now work under Ubuntu 12.04 Precise Pangolin

http://www.webupd8.org/2012/06/how-to-install-vmware-player-in-ubuntu.html


How do I recursively copy/download a whole webdav directory?

This answer summarises suggestions given in comments by @Ocaso and @Rinzwind.

I used this:

wget -r -nH -np --cut-dirs=1 --no-check-certificate -U Mozilla --user={uname}
    --password={pwd} https://my-host/my-webdav-dir/my-dir-in-webdav

Not perfect (downloaded lots of 'index.html?C=M;O=D' and the like) but otherwise worked ok.

The "-r" downloads recursively, following links.

The "-np" prevents ascending to parent directories (else you download the whole website!).

The "-nH" prevents creating a directory called "my-host" (which I didn't want).

The "--cut-dirs=1" prevents creating a directory called "my-webdav-dir".

The "--no-check-certificate" is because I'm using a self-signed certificate on the webdav server (I'm also forcing https).

The "-U Mozilla" sets the user agent in the http request to "Mozilla" - my webdav server didn't actually need this, but I've included it anyway.


Why does Firefox always take much longer to start on its first start?

"Yes, Firefox these days is quite a big program, especially if you have all the goodies turned on.  It can take a noticeable amount of time to start up on any and every platform.  (I run it on Linux, Windows, and Macintosh and it's sluggish-on-startup with all of them.)


No 32-bit upgrade to 18.04LTS from 17.10 on Software Updater

Canonical has finally removed 32-bit ubuntu from their support. So this means you can't get 32-bit 18.04. I believe 32-bit ubuntu will only continue in ubuntu flavours(lubuntu, edubuntu,etc). If you want to upgrade from 17.10, get a .iso file from one of the ubuntu flavours, either burn it to a cd, use startup disk creator to put it on a usb or mount the iso file via:

sudo mount *ubuntu.iso /mnt

You can either boot from it(if you put on a external medium) or find cdromupgrade. It should be in the root filesystem. Or you could try changing your repositorys to bionic instead of artful. You need to edit your sources.list file to do this though. It should be in /etc/apt/.


Dual booting to windows 8.1 failing after first boot

Have you tried updating the grub boot loader with:

sudo update-grub


Installing firefox using Ubuntu Live Media

If you've Ubuntu Live CD/USB, you can get the firefox package from that Live System and install it.

Here is the process.

You need dpkg-repack for this. Install it with

sudo apt install dpkg-repack

If your Live System is an .iso file, you can mount it. If it is a USB, it will be mounted automatically. For iso, the command to mount is

sudo mount /path-to-your-ubuntu.iso /mnt

It will mount the ISO in /mnt directory. If you media is a USB, you'll find the contents of it in directory with path like this /media/tonmoy/USB-drive-name.
Now you need to mount the filesystem.squashfs file which actually contains the Live System. I'm assuming, your ISO or USB is mounted in /mnt for simplicity.

Mount the filesystem.squashfs using this command

First make a temporary directory

  mkdir ~/tmp

mount the squashfs file

  sudo mount /mnt/casper/filesystem.squash ~/tmp

It will mount the live system in the tmp folder in your home directory.
Repack the firefox .deb file. Use this command to extract and re-build firefox from the live system

sudo dpkg-repack --root=/home/tonmoy/tmp firefox

I've assumed that your username is tonmoy. Replace it with actual username

You'll see messages like this while building

dpkg-deb: building package 'firefox' in './firefox_45.0.2+build1-0ubuntu1_amd64.deb'.

Then now install repacked firefox .deb file using dpkg

sudo dpkg -i firefox_45.0.2+build1-0ubuntu1_amd64.deb

It should install the firefox in the system. Now unmount the filesystem.squashfs for being safe (optional)

 sudo umount /home/tonmoy/tmp

Hope that helps.


What's the command to install the build-essential package?

As noted in the comments and linked question, try

sudo apt-get update
sudo apt-get install build-essential

If this isn't working, there's another problem that needs to be solved first.


Turned out cifs utility is not updated automatically when us updates roll out. So after i did sudo apt-get upgrade cifs-utils, it worked fine, i just changed it a little to

[source] [destination] cifs credentials=[creds file],rw,iocharset=utf8,sec=ntlmssp,vers=1.0  0  0

and it worked without a hitch. So for everyone who is looking for solution to this, make sure you UPGRADE your cifs utility :)


Lock screen does not work on Ubuntu 20.04

Holy !@#$% batman! You've got WAY too many GNOME Shell extensions, and many of them overlap in functionality.

First step...

Go to https://extensions.gnome.org/local/ and disable ALL extensions, then restart GNOME Shell with ALT+F2, then r, then ENTER. Then retest the lock screen, and see if it works normally.

Second step...

Let's start by cleaning out your /usr/share/gnome-shell/extensions...

sudo rm -r /usr/share/gnome-shell/extensions/*gcampax.github.com

Restart the GNOME Shell using the previous instructions.

This should leave you with these extensions in /usr/share/gnome-shell/extensions...

drwxr-xr-x  2 root root 4096 May  9 18:04 desktop-icons@csoriano
drwxr-xr-x  3 root root 4096 May  9 18:04 ubuntu-appindicators@ubuntu.com
drwxr-xr-x  3 root root 4096 May  9 18:04 ubuntu-dock@ubuntu.com

Using the same web location that I gave earlier, REMOVE any remaining extensions that you either 1) don't really need, or 2) overlap in functionality. Then re-enable the remaining extensions one-at-a-time to see if one of them causes your lock screen problem. Restart the GNOME Shell after each disable/enable/remove(s) change.


Display name for DEB package in Ubuntu Software Center

You may be interested about apt-cache command with show option. For example, if you want to know the name for gimp package, run the following command in terminal:

apt-cache show gimp | grep "Filename:"

In general, for a package called package, you can use:

apt-cache show package | grep "Filename:" | awk -F'/' '{ print $NF }


The window of calender is out of the screen

Right Click on the Date/Time, and Move. Now the Popup will come to the location where you have put your date/time.


How to get back lost capacity after using Gparted?

The problem appears to be with resizing the Ubuntu file system (likely ext2, ext3, or ext4) with resize2fs 1.42.5.

You might try booting from media containing the latest GParted Live (most recent stable version is 0.16.2-1b).  This live image uses a newer version of resize2fs 1.42.8-1.

This newer version of GParted (0.16.2) will also indicate if there is unallocated space within the partition.


How get rid of the terminal message about sudo

Run a command as sudo, e.g.:

sudo ls

That's all.


How to put an animation sprite on the desktop?

First install shantz-xwinwrap from here, then install gifsicle from the software center.
Now create an empty file on the desktop, open it with gedit and then copy and paste the content of this in it.
Now save the file as gifbg , make it executable then run gksu nautilus and navigate to /usr/bin/ and paste the file there .
Now to use a .gif as a desktop background run gifbg path/to/gif
If you want it to be your wallpaper at every boot then add gifbg path/to/gif  command to your startup applications .

Source and detailed answers at:

Linux Mint Forums
Ubuntu Forums


The -o parameter in aria2c can't rename the downloaded file

You are out of luck when attempting to rename .torrent files with aria2c, from the man pages:

 -o, --out=<FILE>
      The   file name of the downloaded file. When the
      --force-sequential option is used, this option is ignored.

      NOTE:
      You  cannot  specify  a  file name for Metalink or BitTorrent
      downloads.

Note that this information is not contained in the help given with the command:

aria2c -h

but in the man pages that are read with the following:

man aria2c

With other types of files aria2c works very nicely and appropriately renames as directed:

andrew@athens:~$ aria2c -d $HOME/test -o testing.jpg http://www.andrews-corner.org/images/fluxbox.jpg
[#3f8528 32KiB/417KiB(7%) CN:1 DL:87KiB ETA:4s]
06/24 18:29:14 [NOTICE] Download complete: /home/andrew/test/testing.jpg

Download Results:
gid   |stat|avg speed  |path/URI
======+====+===========+=======================================================
3f8528|OK  |   312KiB/s|/home/andrew/test/testing.jpg

Status Legend:
(OK):download completed.

Sorry to be the bearer of bad news...


docker run command ends up in : nginx: [emerg] unknown directive "events" in /etc/nginx/nginx.conf:1

I've very likely, as you have the same problem I ran into, that you've copy and pasted that NGINX conf into Visual Studio.
Open it in Notepad++ change the encoding to UTF-8 (not BOM) and it should work just fine.


Got the same error after last apt-get upgrade. But with gnome-shell --replace it actually started even if it confirmed error.

If you're using the prohibited driver for your fglrx card. One solution can be to Download the amd-driver-installer-12-4-x86.x86_64.run from AMD, using these commands:

wget http://www2.ati.com/drivers/linux/amd-driver-installer-12-4-x86.x86_64.run
sh amd-driver-installer-12-4-x86.x86_64.run --extract
cd fglrx-install.NDh3QS/common/lib/modules/fglrx/build_mod
vim fglrx.patch

and add:

fixed fgrlx compilation error on 32-bit x86 arch with kernel 3.3-rc4 due to commit:
https://github.com/torvalds/linux/commit/f94edacf998516ac9d849f7bc6949a703977a7f3
later modified (in 3.3-rc5) by commit:
https://github.com/torvalds/linux/commit/7e16838d94b566a17b65231073d179bc04d590c8#diff-1
and finally backported to kernel 3.2.8.

This new version adds support for the 3.4 kernels, where some ASM header
file was splitted into several smaller files, so we have to explicitally
include the new file <asm/fpu-internal.h>.

Since 3.4-rc2, cpu_possible_map has been definitely removed. Let's use
cpu_possible_mask instead. This is probably required also for 64 bit kernels.

Signed-off-by: Gianluca Gennari <gennarone@gmail.com>
---
 firegl_public.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/firegl_public.c b/firegl_public.c
index a56fff1..b4bdfb7 100644
--- a/firegl_public.c
+++ b/firegl_public.c
@@ -187,6 +187,9 @@
 #include <linux/gfp.h>
 #include <linux/swap.h>
 #include "asm/i387.h"
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)
+#include <asm/fpu-internal.h>
+#endif

 #include "firegl_public.h"
 #include "kcl_osconfig.h"
@@ -4181,7 +4184,11 @@ static int kasInitExecutionLevels(unsigned long level_init)
 {
     unsigned int p;
     KCL_DEBUG5(FN_FIREGL_KAS, "%d\n", level_init);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,4,0)
+    for_each_cpu_mask(p, cpu_possible_mask)
+#else
     for_each_cpu_mask(p, cpu_possible_map)
+#endif
     {
         KCL_DEBUG1(FN_FIREGL_KAS,"Setting initial execution level for CPU # %d\n", p);
         preempt_disable();
@@ -5799,10 +5806,16 @@ void ATI_API_CALL KCL_fpu_begin(void)
 #ifdef CONFIG_X86_64
     kernel_fpu_begin();
 #else
+#ifndef TS_USEDFPU
+    preempt_disable();
+    if (__thread_has_fpu(current))
+        __save_init_fpu(current);
+#else
     struct thread_info *cur_task = current_thread_info();
     preempt_disable();
     if (cur_task->status & TS_USEDFPU)
         __save_init_fpu(cur_task->task);
+#endif
     else
         clts();
 #endif
--
1.7.5.4

Then execute

patch -p1 < fglrx.patch
cd ../../../../
./ati-installer.sh 8.961 --buildpkg Ubuntu/precise
cd..
sudo dpkg -i *.deb
aticonfig --initial

Now the kernel module is located at /usr/src/fglrx-8.961 and it's now easier to just reinstall (add future patches) with sudo dkms "remove/build/install" fglrx/8.961, read man pages for dkms if you need additional information.


Libreoffice crashes immediately on startup

I have temporarily disabled the apparmor profiles via:

running apparmor_parser -R <path to profile>
usr.lib.libreoffice.program.soffice.bin
usr.lib.libreoffice.program.xpdfimport
usr.lib.libreoffice.program.senddoc
usr.lib.libreoffice.program.oosplash
permanently disabling profile via symlinking <path to profile> /etc/apparmor.d/disable/<profile-to-disable>


Can't boot into ubuntu server; target filesystem doesn't have requested /sbin/init

The error may be because of the user with which you are trying to login to the server.

The user may be having no login shell configured.


gambas2-runtime is in the Ubuntu Software Center for Ubuntu 12.04. For later versions of Ubuntu Gambas2 has been updated to (superseded by) Gambas3. If this doesn't work, you could try installing Nokia Suite on a Windows PC if you have one. Nokia Support Discussions for Nokia Suite is mainly for Windows users.

You can connect your Nokia phone in Ubuntu using wvdial from the Ubuntu Software Center. For information about how to connect your Nokia phone using  wvdial see this step-by-step tutorial: Connect your Nokia phone with Linux without PC Suite.

All of the steps in the tutorial have to be run from the terminal. To open the terminal use the keyboard combination Ctrl+Alt+T. The terminal commands in the tutorial are highlighted in red letters. For example to run the first command in the tutorial, connect your Nokia phone to your computer via data cable, open the terminal and type:

lsusb

This command will list all USB devices that are connected to your computer. You can identify your Nokia phone by looking for a line in the output of lsusb that has something like the string Nokia Mobile in it.

The third command in the tutorial is:

wvdialconf create

If you have already installed wvdial then you can run the preceding command without installing anything else, but this command will not run properly in Ubuntu 13.10, so substitute the following command for it instead:

sudo wvdialconf /etc/wvdial.conf

This will create a file named wvdial.conf in your /etc directory.

The last command in the tutorial is:

sudo gedit /etc/wvdial.conf

This command will not run properly in Ubuntu 13.10, so you have to run the following two commands instead, which will allow you to use Gedit for editing the wvdial.conf file in Ubuntu 13.10:

sudo apt-get install gksu
gksudo gedit /etc/wvdial.conf

It is basically the same command as in the tutorial, only you have to substitute gksudo for sudo to open Gedit from the terminal, because Gedit is a graphical application.

In Ubuntu 18.04 and later gksu has been discontinued so use this command instead:

sudo -H gedit /etc/apt/sources.list &>/dev/null


I'm not sure how you could have got to the state you describe, never the less it seems that the most sensible way to recover would be to boot from the Ubuntu installation CD in "try ubuntu" live CD mode, and use that to transfer your data to a USB pendrive or similar, so that you can then simply install a fresh copy of Windows and then recover your files from the pendrive.


I also had a "cannot specify model number" error.
Turned out, the printer driver was from Canon package (cnijfilter), however, the printer description (PPD) was from GutenPrint package - they are incompatible.

Fixed by changing the PPD file to the one from Canon (Printer properties -> Make and Model -> Change, then select the appropriate driver - mine was called "MG4200 Ver 3.90").


Resolution problem on Intel 950 GPU with Ubuntu 11.10

Install the intel graphics drivers using:

sudo apt-get install xserver-xorg-video-intel

I also have an Intel notebook graphics card and I am wondering that yours works with 10.04 - mine does not. With 11.04 mine does work, 11.10 I have not installed.


How do I run Autocad 13 (not 2013, but #13) on Ubuntu?

You could also create a vm (let's say windows 7) in virtualbox and install autocad in it. You just need a somewhat powerful machine


Running a simulation on pure Ubuntu vs on Ubuntu in Windows (WSL)

Your simulation software is most likely either CPU bound or memory bound.  For such workloads, one would not except to see any significant difference between running the code on "bare metal" or inside WSL (or any other compatibility layer or VM that uses native execution), since in either case the OS is mostly just standing by while the simulation code runs directly on the CPU.

However, it's also possible that your simulation is at least partially I/O bound, and that's where differences may emerge.  Apparently, WSL (currently) has a rather slow filesystem interface layer that can slow down disk I/O significantly.*  That said, while disk I/O can be the major bottleneck for many kinds of bulk data processing tasks, a "simulation" usually should not be spending the majority of its time reading and writing files.  If yours is, you may want to consider running it from a RAM disk (e.g. tmpfs on native** Linux) to avoid needless physical disk access.

In any case, the only way to be sure is to test your simulation in both environments and time how long it takes to run.  Before doing that, however, you may want to take a look at existing benchmarks, like this WSL vs. Docker vs. VirtualBox vs. native Linux performance benchmark by Phoronix from February 2018, and examine the results for any tests that stress the same components of the system as your simulation does.

(FWIW, the Phoronix results seem to mostly match the general principles I outlined above, although there are a few notable oddities like VirtualBox apparently outperforming native Linux in a few I/O bound benchmarks, apparently due to its virtual disk not always immediately syncing data to the physical disk.  One potentially relevant issue that I failed to note above is that the benchmarks show significant differences in multi-threaded OpenMP performance both between the different host environments and also between different Linux distros even when running on bare hardware.  In hindsight, that's not too surprising, since threading and IPC is handled by the kernel.  I'd guess that much of the difference between the distros there may come down to different runtime and/or compile time kernel tuning parameters.)

*) According to this MSDN blog post from 2016, there are actually two filesystem interface components in WSL: VolFs, which closely emulates native Linux filesystem semantics over NTFS and is used to mount e.g. / and /home, and DrvFs, which provides mostly Windows-like semantics and is used for accessing the host Windows drives via /mnt/c etc.  If your software doesn't specifically require native Linux filesystem features like multiple hard links to the same file, configuring it to store its data files in a DrvFs folder may improve file access performance on WSL.

**) According to this Reddit thread from May 2017, "tmpfs is currently emulated using disk" on WSL.  Unless something has changed over the last year, this presumably means that using tmpfs on WSL gives no performance benefit over using a normal on-disk filesystem.


Which package to install to get header file glad.h?

Thanks to @dc37 for the comment on the webservice! Here is what I did: Go to the webservice and download the required files:

Click the "Generate" button in the lower left corner:

and download the glad.zip file to the current directory. Extract it. Create a test program test.cpp:

#include <iostream>
#include "glad.h"
#include <GLFW/glfw3.h>
void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

int main() {
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
    GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
    if (window == NULL) {
            std::cout << "Failed to create GLFW window" << std::endl;
            glfwTerminate();
            return -1;
    }
    glfwMakeContextCurrent(window);
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }
    glViewport(0, 0, 800, 600);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    while(!glfwWindowShouldClose(window)) {
        glfwSwapBuffers(window);
        glfwPollEvents();
    }
    glfwTerminate();
    return 0;
}

Compile it (remember to install libglfw3-dev first):

g++ -c glad.c
g++ test.cpp -o my_test glad.o -lglfw -ldl

Run it:

$ ./my_test

(It shows an empty window on the screen)


How to sudo chmod -R 777 * including hidden files?

Universal:

chmod 777 -R ./* ./.[!.]*

Bash has this command

shopt -s dotglob

to also include hidden files in commands (shopt -u dotglob to disable that behaviour) if you want to stick to using sudo chmod -R 777 *.

It will break your system if you execute it from the wrong directory.
NEVER use a bare * but use ./*.
the shopt method is more secure than the universal one


The name was change to Additional Drivers as one of the One Hundred Paper Cuts. See here : Change the name of "Hardware drivers"

The principal reason for the change was that the name Hardware Drivers was confusing as the tool only manage non-free drivers and not all the drivers.


Lugaru game doesn't go full screen in 12.10

Open bash script /usr/games/lugaru

Delete code inside and paste this code:

#!/bin/sh

cd /usr/lib/games/lugaru || exit 1
exec ./lugaru -fullscreen


Problem in redirecting standard input and output

The reason why it fails is that mysqldump does not read the standard input; table1 and table2 are (optional) arguments, but you are providing them not on the command line, but on stdin.

If $2 is the filename of a file that contains one line with the text table1 table2, then the following should work:

mysqldump -h localhost -uroot --lock-tables=false db `cat $2` > ~/backup/$name'.sql'

Bash will expand this command line to

mysqldump -h localhost -uroot --lock-tables=false db table1 table2 > /home/user/backup/somename.sql

which is what you want to run.

However, since you are using getopt anyways, maybe you could put "table1" in $2 and "table2" in $3, and run just

mysqldump -h localhost -uroot --lock-tables=false db $2 $3 > ~/backup/$name'.sql'


First get a copy of a Windows 98 Startup Disk that has fdisk on it (it will repair the MBR if GRUB has errors see down this text).

You should start the live cd (the same cd as the version installed), chroot into the partition of linux (man chroot) and from there (not sure if it will work):

sudo nano /etc/fstab       ->  remove the /boot entry

sudo mkdir /boot

sudo apt-get install -y linux grub2

sudo init 6

If this did not work and Windows does not start any more, insert the Windows 98 Startup Disk, boot from it and in the command line do:

fdisk /mbr


How can I make my shell prompt look like a cheeseburger?

great choice!

$ sudo apt-get install ttf-ancient-fonts
$ export PS1="\\u@\h \\w  "

enjoy.


In that folder run:
for i in *.png*; do
    mv -i "${i}" "${i%.png*}.png"
done

as a one-liner, this becomes
for i in *.png*; do mv -i "${i}" "${i%.png*}.png"; done

This loops over all the files matching *.png* in the current directory and renames (moves) them by cutting off everything starting at the last occurence of .png and then appending .png again. Using %% instead would start cutting off from the first occurence of .png. You can drop the -i if you don't want to confirm overwriting existing files.


In Ubuntu 12.04 (and above), you can start the Privacy and Activity Manager from command line, type privacy in the Dash or any of the way that you prefer.

Here's a snap of the manager window.


Swap is not faster than of your disk, think about it in form of manufacture, how can your car becomes faster without any tuning of its physical parts?

mkswap is somehow like other mkfs utilities, it prepares your file or partition to be used as a swapping space in a special form which it can't be thought of any other kind of file systems. it prepares a portion of your disk which might be upon a file system itself (a swap file) to save the memory pages directly into it. That might be the reason of feeling it being a little bit more faster.

Also it's nice to read: Does swap space have a filesystem?


Running a service will not bind to ports # 443 and # 80 despite application of sudo setcap 'cap_net_bind_service=+ep' /path/to/binary

Turns out I specified the wrong ipaddress in my bind, that came from an environment variable passed at compilation time. Setcap works great.


Delete the existing epson icon in the PRINTERS folder; if not working; (right-click and select DELETE)

One generally starts here on the official download page for Epson drivers

I can point you directly to this page

For Ubuntu 64bit, you need epson-inkjet-printer-escpr_1.6.13-1lsb3.2_amd64.deb. As you click to download, the query box will ask you if want to open the file: click yes, as that opens the Gdebi installer so which will install the package.

For a printer, you need to

install the drivers
register the printer

The latter may not automatically happen: an entry should be created for you in the PRINTERS folder, if not you need to do it manually


Installing Ubuntu in a partition made previously

Follow the steps

Take backup every thing in D: drive. Because all data will be lost.
Boot with live usb
There will be screen asking for install options like install along with windows 7,install ubuntu as only OS etc. Choose Do something else option at the end.
Now partition tool will open.  Delete the disk you want to install ubuntu to. You can see the unallocated space. Select that and then click on Add.
Now we will add SWAP partition. Give disk space value as 1024MB (1GB) or 2GB. If you have good amount of RAM (~2GB), 1GB swap space is enough. Select SWAP in file system dropdown.Press "OK".
Now again continue previous step for the rest free space (or whatever size you want for ubuntu installation). This time select filesytem as ext4 and mount point as /.
Check in partition tool window, grub installation location is same as your hard disk not your usb disk. (most likely bootloader location -> in sda ...)
Now go ahead and installation will finish in minutes.

Note: Don't enable downloading of 3rd party apps and update in previous screen. Better don't connect to internet while installing.Good luck. Let us know how it went.


Ubuntu won't boot after installation on second hard drive?

Your HDD needs to be partitioned using GPT not MBR which is usually the default, then the UEFI BIOS should find it ok. It's a good idea to use the Ubuntu disk partitioning tool in the Live disk to setup your partitions before you begin the install so it's easier to see what you're doing and where everything is going.

Also you need to set the first drive which I'm guessing is your Windows SSD as the location for the bootloader in the /EFI partition on the SSD (probably /dev/sda ). That way the installer will find your Windows boot files and let GRUB give you the option of which OS to boot.

On the subject of partition sizes, with 16gigs of RAM you don't need a 20gig swap. No need to create a swap partition at all really as the installer will create a swapfile in root for you. And unless you intend to "hibernate" Ubuntu (suspend to disk), you don't need more than a gig or two of swapfile. If you will be hibernating then you'll need a 16gig swapfile. I have 32gigs and no swapfile at all as I have plenty of RAM to run everything I need without running out of memory. YMMV.


Most efficient way for handling multiple files

Suggested tools

There are manuals in the operating system, for example

man ls
man find
man sort
man rm
man less

Maybe you find it better to use tutorials, that you can find via the internet, for example via the search string linux less tutorial.
It is a good idea to have a clean dedicated directory or directory tree, with only the audio file clips, so that you need not worry about tampering with any other files, that you want to keep. It will make the commands simpler and easier to run.
It is possible to have other files there, but then you must specify the file type for the files that you want to manage, for example *.mp3.
In the following examples, I assume that you have a clean dedicated directory or directory tree, with only the audio file clips, and that all files, that you want to keep are outside that directory.
In a terminal window you can re-use commands via the 'up-arrow' key.
You can also create alias so that you can type very short commands and get the whole command, that will perform the action you want. More about that later if necessary.

  You normally do the following operations

First you change directory to your dedicated directory

cd /path-to-directory/

for example

cd $HOME/clips

  sort by file size and play the largest file

ls if a flat structure (no subdirectories to search)

ls -Sr

find and sort if there are subdirectories to search

find -type f -printf "%s\t%p\n"|sort -n

will sort with the largest file last.

If you want to play that file directly in a flat structure, you can try with

mplayer "$(ls -S|head -n1)"

(or use some other player).

  delete all audio files if you find something wrong

rm

In a flat directory

    rm *

or if there are subdirectories with files to delete

    rm -r *

If there are other file types, that you want to keep, remove only the audio files for example mp3,

    rm *.mp3
    rm -r *.mp3

  and see the file names in general if they are named as per requirement
  correctly.

ls and less

ls | less

or if you want one file on each line

ls -1 | less


Ubuntu 18.04 alt+shift+tab does not switch apps backwards

That's because Alt+Shift+Tab in Ubuntu 18.04 is blocked by another shortcut.

Run this command to free the Alt+Shift combination:

gsettings reset org.gnome.desktop.input-sources xkb-options

source1 source2


Why does `do-release-upgrade` skip a version?

Your original guess was right. 15.04 is supported through 2016-02-04, so do-release-upgrade is trying to upgrade you to the next supported release compared to the one you have.

Here's the description of normal upgrade prompting mode from /etc/update-manager/release-upgrades:

  Check to see if a new release is available.  If more than one new release is found, the release upgrader will attempt to upgrade to the release that immediately succeeds the currently-running release.

So if I'm on 14.04 it should be trying to take me to 14.10, but right now do-release-upgrade is trying to take the OP (and me) to 15.04 instead.

So reading through /usr/lib/python3/dist-packages/DistUpgrade/MetaRelease.py it looks like we skip unsupported releases when figuring out what release to upgrade to (unless you're using the developer flag):

    # then see what we can upgrade to
    upgradable_to = ""
    for dist in dists:
        if dist.date > current_dist.date:
            # Only offer to upgrade to an unsupported release if running
            # with useDevelopmentRelease, this way one can upgrade from an
            # LTS release to the next supported non-LTS release e.g. from
            # 14.04 to 15.04.
            if not dist.supported and not self.useDevelopmentRelease:
                continue
            upgradable_to = dist
            self._debug("new dist: %s" % upgradable_to)
            break

I should add that I do not recommend trying to get around this with do-release-upgrade -d. When I tried it with prompt=normal, I got 404s, since 14.10 is EoL. I also think in my delirium I must have tried do-release-upgrade -p, which tried to take me straight to 16.04. By the time I realized it was taking me to xenial everything was broken and I had to restore from factory. In the end I decided I'll wait until 16.04 is released and do a fresh install.


Press CTRL-ALT-F1 to enter console.

ps ax|grep screen

kill -9 all screensaver related task.

CTRL+ALT+F7 to retrun to gnome desktop.


how can I reinstall ubuntu without internet connection

Download a liveCD from anoter computer and burn a CD.


Unable to add PPA repository in ubuntu 18.04

with your browser, go to google.com

enter "gpg key servers" with out quotes in the search box

Look through the results for alternate gpg servers

Choose any one you wish, any one should work, put the alternate gpg server in your command

code :

sudo apt-key adv --keyserver keyserver.your.found.from.google --recv-keys 35DA01C261E46227

substitute "keyserver.your.found.from.google" with any of the alternate key servers listed from your google search.


In all recent versions of Ubuntu, you should see your partitions in the dock on the left. Note that the partition on which Windows was present will be called "200 GB Volume" or something like that. Just click on the relevant partition, and you'll be able to browse it, and go to whatever folder your work is located.


Asus K75VM laptop fans not detected, Ubuntu 16.04

You have an Asus K75VM laptop which has an Intel H76 chipset. The mobile version of this chipset has no fan control outputs so you do not have the necessary hardware for software fan control under any operating system.

Your fan speed is controlled by your BIOS. It sounds like it is working as intended as 50 degrees Celsius is a normal temperature for a laptop CPU. If you want to tune the fan or power management setings you can probably find these under the advanced settingspage of your BIOS.

laptop-mode tools and tlp do much more than attempt to control the fan speeds. Install one or the other but not both.


The key to be pressed is the regular E on the keyboard, which starts GRUB's Edit Mode.

The Edit Mode is useful if you want to temporarily over-ride settings in your /boot/grub/grub.cfg or append something (like a kernel option), to the end of a line in a boot stanza just for one boot-up.

When you get this screen -

Press E -


How to open pseudo-terminal devices on terminal?

/dev/ttyACM0 sounds like a serial device. You can use a terminal emulator program to speak to a serial device.

For example, the screen program has this functionality built in. You can connect to a serial device at 115200 bps using the command screen /dev/ttyACM0 115200. You manual should tell you the speed you need to use on your device; 9600 bps is another common speed. You may need to install screen first using the command sudo apt-get install screen. To close screen when you're done, press Ctrl-a, release, and then press k.

Presumably you would then press buttons on your keyboard and see data appear in the terminal emulator window.


cqpweb triggers error "DATABASE CACHE OVERLOAD!"

Due to an inquiry on the CWB mailing list I have learned that the cache in question is maintained by the application (cqpweb) and that the Ubuntu upgrades on php and mysql aren't the problem.

In my case, the solution is to enlarge the application cache.


The infrastructure for publishing paid snaps in place. We're not quite ready to launch yet. We wouldn't want to launch a service for paid snaps without all the necessary testing and support infrastructure in place. It's coming though.


Why are the manually added notification icons don't hide when using workspace switcher?

Fixed in CCSM; Compiz config settings Manager.

Go to  Expo - Appearance - Check hide panels/dock:

Here is a new screenshot without the manually added notification icons :


Slow menu and icon issue in the launcher with LibreOffice 4.1

I had this and additional problems - Impress actually locked up my computer when I opened a specific file - and I got into a lot of headaches when I rolled back.  Here is the right way to do it. From terminal:

  sudo apt-get autoremove libreoffice (do NOT remove the PPA first!)

Now go to Ubuntu Software Center, Edit | Sources | Other Software and remove the PPA for LibreOffice

  sudo apt-get update

  sudo apt-get install libreoffice


How to set the project sources JDK version in Netbeans?

In your Projects tree, expand the Build Scripts and edit the build.gradle file.

You should find somewhere a line that contains :
sourceCompatibility = '11'

Edit this line and change it to sourceCompatibility = '14'.

Clean and build your project, and re-open the project properties. You should now see your Source / Binary format to 14.

By the way, this information does not mean that your IDE is stuck on 11. It is just the target JVM version of your application. Having '11' will keep your code compatible with a JVM 11.
If your code is intended to run on a server for which you or a sysadmin manage the JVM version, you can choose the version you prefer and benefit from the latest JVM updates.
But if you plan to distribute a rich-client application that will run on a config that you don't know, I would rather consider keeping this compatibility as "old" as possible. Some people still have a JVM 1.8 on their computers, and probably not a majority uses Java 14 ;)


Ubuntu 14.10 desktop issue launcher and theme issue

you can reset unity and compiz by the following commands in the terminal

sudo apt-get install dconf-tools

and then

dconf reset -f /org/compiz/

After that, run the below command to restart Unity

setsid unity

and then to reset the icons use the following code

unity --reset-icons


It seems that the problem was not related to the KDE installation, but to the msfonts.

I removed the mscorefonts, logout and I got my fonts reverted to the original ones.

sudo apt-get purge ttf-mscorefonts-installer


I had the same problem on a regular ubuntu (gnome) the hints on rfkill made me get my connection switched on. If you encounter the "hardware switched off" problem, try to reset your bios (I have a Lenovo E130 laptop) which helped in this case.


Advantages of separate /home partition on HDD + SSD setup

The problem with putting /home on a spinning disk is that a bunch of things that could take advantage of the SSD (like all the tiny files your browser uses for example) would be on the HDD instead of the SSD, you can mitigate this by using some symlinks:

How do I symlink certain directories in /home to an SSD?
What in /home would benefit from being on an SSD?

In this case, you're probably better off putting all of ~.config on the SSD. I wouldn't worry about keeping writes to a minimum, newer SSD drives don't have that problem.


To answer your question, you can safely uninstall the Ofono package (assuming you're not using it for its intended purpose) with a call to sudo apt-get purge ofono. It's quite likely that the error generated was because, according to your system specs, you don't have a wireless radio that would use Ofono services (i.e., GSM/UMTS).

I'm curious about why you have this installed on your machine. Is (was) there a reason for installing Ofono initially (it's an interesting package)?


Might be best to boot using a LiveCD and then browse through to find what you had changed.

Remender that

gksudo nautilus

will get you to the file browser with root privileges so you can change any files


difference between sources.list and sources.list.distUpgrade

When you upgrade between distro versions, .list files in /etc/apt/sources.list.d get commented out. The original versions of those files get backed up with the .distUpgrade extension, and that's what you're seeing. Other than sitting there and being backups, I don't think the .distUpgrade files do anything.

I guess Ubuntu (Debian?) does this out of the presumption that .list files will be incompatible across distro versions, but as a packager, this is pretty inconvenient. Packages like google-chrome install a special cronjob just to work around this issue and un-comment-out their .list file after a dist upgrade.


How to create username from firstname lastname initials in csv file?

If the CSV file looks like this:

Firstname,Lastname
Joe,Miller

Then open it up in Calc.  In cell C1, enter this formula:

=LOWER(LEFT(A1,2) & LEFT(B1,2))

Then use the square in the lower right corner of cell C1 to fill the formula down the C column.  Results:

fila
jomi

If there are thousands of rows, then it may be easier to select the entire C column by clicking on the C column heading, then Edit -> Fill -> Down.


Cannot forward local port to another local port

The iptables REDIRECT directive is the appropriate method for same machine port forwarding:

sudo iptables -t nat -A PREROUTING -p tcp -d 192.168.47.5 --dport 7777 -j REDIRECT --to-port 3000

As a demonstration and how to verify example I will use a computer at 192.168.111.122 and redirect port 7777 to port 22, where I have sshd listening. So (notice I added a network interface qualifier):

sudo iptables -t nat -A PREROUTING -i enp3s0 -p tcp -d 192.168.111.122 --dport 7777 -j REDIRECT --to-port 22

Now, I use another computer at 192.168.111.1 to check it (note: not really trying to telnet, just checking if it can connect):

doug@DOUG-64:~$ telnet 192.168.111.122 7777
Trying 192.168.111.122...
Connected to 192.168.111.122.
Escape character is '^]'.
SSH-2.0-OpenSSH_8.1p1 Ubuntu-5

Invalid SSH identification string.
Connection closed by foreign host.
doug@DOUG-64:~$

O.K. that seemed O.K. Try ssh:

doug@DOUG-64:~$ ssh -p 7777 192.168.111.122
doug@192.168.111.122's password:
Welcome to Ubuntu Focal Fossa (development branch) (GNU/Linux 5.5.0-rc6-stock x86_64)
... a bunch deleted ...
Last login: Fri Feb  7 15:32:45 2020 from 192.168.111.1
doug@s18:~$
doug@s18:~$ logout
Connection to 192.168.111.122 closed.
doug@DOUG-64:~$

And also check communications at the packet level, during a session, via a tcpdump (or wireshark, if you prefer) session on 192.168.111.122:

doug@s18:~/temp-git-git$ sudo tcpdump -n -nn -tttt -i enp3s0 port 7777
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp3s0, link-type EN10MB (Ethernet), capture size 262144 bytes
2020-02-07 15:37:16.480311 IP 192.168.111.1.45918 > 192.168.111.122.7777: Flags [S], seq 494277163, win 29200, options [mss 1460,sackOK,TS val 349415894 ecr 0,nop,wscale 7], length 0
2020-02-07 15:37:16.480329 IP 192.168.111.122.7777 > 192.168.111.1.45918: Flags [S.], seq 2825406220, ack 494277164, win 65160, options [mss 1460,sackOK,TS val 2718854230 ecr 349415894,nop,wscale 7], length 0
2020-02-07 15:37:16.480600 IP 192.168.111.1.45918 > 192.168.111.122.7777: Flags [.], ack 1, win 229, options [nop,nop,TS val 349415894 ecr 2718854230], length 0
2020-02-07 15:37:16.486525 IP 192.168.111.122.7777 > 192.168.111.1.45918: Flags [P.], seq 1:33, ack 1, win 510, options [nop,nop,TS val 2718854236 ecr 349415894], length 32
2020-02-07 15:37:16.486668 IP 192.168.111.1.45918 > 192.168.111.122.7777: Flags [.], ack 33, win 229, options [nop,nop,TS val 349415896 ecr 2718854236], length 0
2020-02-07 15:37:18.016165 IP 192.168.111.1.45918 > 192.168.111.122.7777: Flags [P.], seq 1:3, ack 33, win 229, options [nop,nop,TS val 349416278 ecr 2718854236], length 2
2020-02-07 15:37:18.016175 IP 192.168.111.122.7777 > 192.168.111.1.45918: Flags [.], ack 3, win 510, options [nop,nop,TS val 2718855766 ecr 349416278], length 0
2020-02-07 15:37:18.016262 IP 192.168.111.122.7777 > 192.168.111.1.45918: Flags [P.], seq 33:67, ack 3, win 510, options [nop,nop,TS val 2718855766 ecr 349416278], length 34
2020-02-07 15:37:18.016408 IP 192.168.111.122.7777 > 192.168.111.1.45918: Flags [FP.], seq 67:69, ack 3, win 510, options [nop,nop,TS val 2718855766 ecr 349416278], length 2
2020-02-07 15:37:18.016428 IP 192.168.111.1.45918 > 192.168.111.122.7777: Flags [.], ack 67, win 229, options [nop,nop,TS val 349416278 ecr 2718855766], length 0
2020-02-07 15:37:18.016589 IP 192.168.111.1.45918 > 192.168.111.122.7777: Flags [F.], seq 3, ack 70, win 229, options [nop,nop,TS val 349416278 ecr 2718855766], length 0
2020-02-07 15:37:18.016600 IP 192.168.111.122.7777 > 192.168.111.1.45918: Flags [.], ack 4, win 510, options [nop,nop,TS val 2718855766 ecr 349416278], length 0
12 packets captured
12 packets received by filter
0 packets dropped by kernel

doug@s18:~/temp-git-git$ sudo iptables -t nat -v -x -n -L
Chain PREROUTING (policy ACCEPT 38 packets, 4409 bytes)
    pkts      bytes target     prot opt in     out     source               destination
       4      240 REDIRECT   tcp  --  enp3s0 *       0.0.0.0/0            192.168.111.122      tcp dpt:7777 redir ports 22

Chain INPUT (policy ACCEPT 40 packets, 4329 bytes)
    pkts      bytes target     prot opt in     out     source               destination

Chain OUTPUT (policy ACCEPT 2 packets, 228 bytes)
    pkts      bytes target     prot opt in     out     source               destination

Chain POSTROUTING (policy ACCEPT 2 packets, 228 bytes)
    pkts      bytes target     prot opt in     out     source               destination
doug@s18:~/temp-git-git$

The packet counters are very useful. Note that the PREROUTING path would only be traversed once per connection (I had done it 4 times, when I ran the above command).

If you make a mistake and need to delete your rules and start again, do:

sudo iptables -t nat -F

to clear the nat table rules. This answer might need to be incorporated into a bigger iptables rule set or UFW context.

EDIT: Oh, by the way:

doug@s18:~/temp-git-git$ grep . /proc/sys/net/ipv4/conf/*/forwarding
/proc/sys/net/ipv4/conf/all/forwarding:0
/proc/sys/net/ipv4/conf/default/forwarding:0
/proc/sys/net/ipv4/conf/enp3s0/forwarding:0
/proc/sys/net/ipv4/conf/lo/forwarding:0
doug@s18:~/temp-git-git$ grep . /proc/sys/net/ipv4/ip_forward
0


Disable Keyboard Repeat from command line?

You can use the xset utility, which works on the X.org level, across desktop environments. (The dconf / gsettings solution is Gnome specific.)

To switch off keyboard repeat:

xset r off

To switch keyboard repeat on again, with the same delay and rate settings as before:

xset r on

See man xset for details.


You can use WebcamStudio in order to manage your webcam orientation and change or enrich your webcam experience with some extra features such as:

Integrating animations and/or text layers to your video stream.
Use a pre-recorded fixed image/gif animation/video for broadcasting
over your preferred video conferencing system.
Use several sources in the same session, switching from a device to
another just in a click.

A screenshot from the web is placed here for your convenience:

Basically, what Webcam Studio does is to provide your system with a virtual "bridge" between your physical webcam and what the video conference software is expecting to find, thus the ability to enrich the streamed video with effects/filters/animations/etc.

Good luck!

P.S. Usage of the webcam studio software can be combined with Empathy/Skype/Google+ Hangouts and other flash based video conferencing web services.


Did I break my system with apt-get autoremove?

If your system is running all right prior to doing autoremove then the answer is No, you have not broken anything by doing autoremove.

apt-get autoremove removes orphaned dependencies i. e. packages that were installed as dependencies of desired package(s) but became orphan after those desired packages have been removed/purged.

So, unless you have not removed anything necessary before doing autoremove, you can not break the system by only running it.


How to fix the partitions' number on GPT disk (/dev/sdaX)

You may use gdisk to rewrite the partition-table:

sudo gdisk /dev/sda
p  (the p-command prints the recent partition-table on-screen)
s  (the s-command sorts the partition-table entries)
p  (use the p-command again to see the result on your screen)
w  (write the changed partition-table to the disk)
q  (quit gdisk)

You will find most useful information about gdisk at http://www.rodsbooks.com/gdisk/