As you added the tag ufw i'm guessing you are using the default ubuntu firewall manager ufw and not iptables you can disable the ufw firewall with

sudo ufw disable

ufw has an excellent manual you can access it with man ufw


The underlying filesystems used by Ubuntu, like ext2 and ext3, simply don't need defragmenting because they don't fragment files in the same way as NTFS. There are more details at ext3 - Wikipedia, the free encyclopedia


Corrupt plymouth boot screen when using properietary Nvidia drivers

I got corrupt boot and terminal screens (white blocks with black lines) when installing 11.04 with an nvidia graphics card, though X server itself was okay.  I fixed the problem by apt-get install startupmanager, running startupmanager and increasing the boot screen resolution and colour depth.


I had this problem after I installed cinnamon, had to remove it.  Wish I could comment.


merge files in different directories running a script on terminal

When having simple text files, you can merge them without difficulties by using the >> operator. It will add the output of the previous command to the end of the file specified after.
Basic Procedure (not for many files)
Example:
Imagine a directory structure like this:
parent
 |--a
 |  \--first.txt
 \--b
    \--second.txt

Now the contentents of a/first.txt are
Hello! This is my first Textfile.
   ~~some lines~~
end

and b/second.txt contains
    ///////////////////
   //               //
  //  second file  //
 //               //
///////////////////

So we can merge it by typing:
$ touch merge.txt
$ cat a/first.txt >> merge.txt
$ cat b/second.txt >> merge.txt

A new empty file merge.txt in the current directory will be created and the files contents will be added without overwriting, like > would do.
merge.txt now contains:
Hello! This is my first Textfile.
   ~~some lines~~
end
    ///////////////////
   //               //
  //  second file  //
 //               //
///////////////////

Done!
Advanced Scripting (to cover many files in different directories)
If you have more than ten files, maybe even in ten different directories, you can make a bash script and let the computer do all the selecting and copying on its own. If you're completely new to bash or shell scripting, I'd recommend you to read a little beforehand about what it is capable of and getting a basic understanding of the appearence of variables and loops, so you don't get too confused.
I'm using the top of http://www.cyberciti.biz/faq/bash-loop-over-file/ as a reference now. Our script will look basically like this:
#!/bin/bash

FILES="file1
/path/to/file2"

OUTPUT="merge.txt"

for f in $FILES
do
    cat $f >> $OUTPUT
done

(Oh, I hope this will work)
If all your files share something that differenciate them from other files we don't want to merge, that's exactly what we need. Ideally they share a common parent or anchestor folder where you can't find any other files but ours. Then we can simply use /the/path/to/that/folder/* as selector when defining our $FILES variable. As you see in the model, we can set multiple selectors. I hope you don't care too much about the order the files will be selected automatically, else we'd have to think about some way to specify this... For our example above, we could set:
FILES="*/*" or FILES="*/*.txt" or FILES="a/* b/*" or so and
OUTPUT="merge.txt" of course.
Some last thoughts
Maybe we'll need to pay attention to not selecting our merging file with "*", that may end awkward... Above I therefore included one / everytime. You also could simply put it somewhere else.
If your files follow some pattern, like p_some-thing-axy-1,p_some-thing-axy-1,p_some-thing-bxz-1, you can choose some selector like p_some-thing-* or so.
Now I hope you can make some use of that, because I'm out.
Good luck! :D


You don't need to install anything to create a purely virtual audio device in ALSA. Load snd-aloop with the following command:

modprobe snd-aloop

You also asked about a good virtual audio software. Another software that may be useful is alsa-utils which is run from the terminal:

sudo apt install alsa-utils


After fighting for long with this issue, found some link where its mentioned to try disabling ipv6 and it should work.
referred this link to disable ipv6
https://itsfoss.com/disable-ipv6-ubuntu-linux/
sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=1

though there is mechanism mentioned to do disable ipv6 permanently  I preferred to create is a command which i will execute only when i want to connect to citrix.
working smoothly for me (with ubuntu 20.04, citrix workspace).


This really has nothing to do with Ubuntu. You probably want to file a bug against rtbth with these errors:

rtbth_core_bluez.c:216:2: error: too few arguments to function ‘hci_recv_frame’
  status = hci_recv_frame(skb);
rtbth_core_bluez.c:406:6: error: ‘struct hci_dev’ has no member named ‘ioctl’
  hdev->ioctl = rtbt_hci_dev_ioctl;


Install a guest Win10 in VirtualBox in Ubuntu 20.04 from USB

With the command you refer in your point 1) you create a raw vmdk device who points to the /dev/sda1 partition. However, when you try to access it you get a permission error. So my guess is that, although you have the right permissions on the usb.vmdk file you just created, you probably don't have read/write access to the raw partition device, which is where VirtualBox ultimately goes.
Try ls -l /dev/sda* and check the permissions. As you will use this raw vmdk device solely for installation purposes, I suggest to temporarily allow access to everyone to this device: chmod a+rw /dev/sda1.
I just had this identical problem and that solved the error for me.


How to change description of Refind entries?

Yes, there is. Your description is a little thin on information. I don't think I can give a complete answer based on what I have read. Basically, you add a manual entry in refind.conf and add line to remove the option with the ugly label. I assume you are looking for something like this. (Click on image for a better view.)

To produce the above menu, I added the following lines to the default refind.conf file. Again, I do not know enough about your computer to list the changes you will have to make.

scanfor manual,internal,hdbios,external,biosexternal,optical,cd
dont_scan_dirs +,/System/Library/CoreServices
menuentry "Mac OS X" {
    icon \System\Library\CoreServices\icons\os_mac.png
    volume "Steelhead"
    loader \System\Library\CoreServices\boot.efi
    graphics on
}
dont_scan_dirs +,EFI/ubuntu,Bullhead:/boot
menuentry "Linux Ubuntu" {
    icon \System\Library\CoreServices\icons\os_ubuntu.png
    volume "Bullhead ESP"
    loader \EFI\ubuntu\grubx64.efi
    graphics on
}
showtools shell,memtest,gdisk,apple_recovery,windows_recovery,about,shutdown,reboot,firmware

Also, when holding down the Option key at boot, you can have the Ubuntu option appear as follows.

On the OS X Startup Disk menu, you can have Ubuntu appear as follows.


Multiple Dropbox accounts on the same computer

I went ahead and tried this out. The first installation was successful in the normal way; when I tried running Dropbox for the second user, I was prompted to download the proprietary daemon. It seemed strange to me that I would need to do this twice, but I did it and set up the second account successfully, too.

So far I haven't noticed any adverse effects, and I've had both users signed in simultaneously.


Screen flickers white after Ubuntu 17.10 upgrade

This can be a factor of compositing

we can try to disable vsync in your VM by creating a file in /etc/profile.d

name it say script.sh

export vblank_mode = 0

then logout and login again

see if those white flicks will be gone


Problems with installing Ubuntu 12.04 alongside Windows 7

How did you get the CD?  Was it: a) Purchased from Canonical, b) Included in a Magazine issue, or c) Downloaded from the website?

If it was downloaded, was it: a) Direct download from Ubuntu.com or b) A torrent download?

I've had issues installing 12.04 from CDs provided in magazines as well as ISOs downloaded via torrent.  So far, I've had the best luck installing from a CD or USB stick created from a direct download disk image.

Others have reported installer issues with 12.04 on specific hardware.  Perhaps try a different source and see if you have the same problem?


I don't have the ssh-copy-id command (windows client)

With putty, you can upload public key manually, assuming you now can access the server with username and password:

Generate the key file, with the guide you followed it will be .pub file, the content of the file should shart with "ssh-rsa AAAA ...."
Login to the server machine
Copy the content of the .pub file into the ~/.ssh/authorized_keys file (for this use vim, nano or your favourite text editor)

If your SSH directory does not exist, create it and then copy the pub file into the ~/.ssh/authorized_keys:

mkdir ~/.ssh
chmod 0700 ~/.ssh
touch ~/.ssh/authorized_keys
chmod 0644 ~/.ssh/authorized_keys
nano ~/.ssh/authorized_keys
...

Now you should be able to login with your private key file.


Dual-boot problems, installing Ubuntu alongside Windows 8.1

Did the Ubuntu entry you added in EasyBCD show up when you restart Windows?

If no, go to run > msconfig > second tab (Boot) > increase timeout and restart.

If yes, did it work? If it showed up but didn't work, try editing the Ubunty entry in EasyBCD by specifying the drive for your boot (or root?) partition.


Most computers have a setting in the BIOS to turn on the computer by various means, including time and date.  I used to always have my computer come on at a certain time every day before I came home from work, and I had backups scheduled for this time.

This worked even if the computer was totally turned off, not on standby.  Of course, it had to have power available (it was a desktop).

It's pretty hard to give exact directions, because it depends on computer and BIOS.  But you need to press the secret key while booting to get into the BIOS, then poke around to find the power settings.

Turning off is, as you've said, done by various software, including cron.


Combine each two pages to single from pdf book

You can use pdfjam from the texlive-extra-utils to combine pages horizontally or vertically in one page.
Also the tool montage from Imagemagicks (installed by default) can do that.
For simple cases, just printing to a PDF may do the job. In the Print dialog of your application, select "Print to file". On the "Page setup" tab, you can indicate that multiple pages must be printed on a single page.


Problems with 17.10: Blender, Atom, and other programs

Don't know if you figured it out or not, but for others who may be looking for a fix, I have the same exact issue.  Searching around through Google, I was able to find this thread which seems to indicate it's an issue with Blender and XWayland (I don't fully understand the issue though)

After a bit more searching I found this question / solution for a little different problem.

Basically, in Blender, go to File -> User Preferences -> System and set Window Draw Method to Triple Buffer.  So far it's working pretty good for me.

Note: I'm using and AMD Radeon HD 7950 with the open source driver.


Using Ubuntu as a gateway for monitoring and possibly IPS IDS within Active Directory

It sounds like what you are looking for is a bridge.

For this, you will need at least 2 network interfaces on your Ubuntu box.

I'll assume that your system has named the two network adapters eth0 and eth1.

First, you will need to install the bridge-utils package. (I'm not sure if you are using a CLI server version or a desktop version that has a GUI installed. So I will tell you how to do stuff CLI because that's lowest common denominator). You can do this by running sudo apt-get install bridge-utils.

You will want to edit /etc/network/interfaces to tell the machine how you want the network configured (including across reboots), so run something like sudo nano /etc/network/interfaces.

Remove any lines related to eth0 or eth1. This includes lines that may be indented under lines like auto eth0 or something like that. (Leave stuff about lo alone, that's the loopback interface, and you want to leave it as it is). Then add a few lines to the end of the file:

auto br0
iface br0 inet static
        bridge_ports eth0 eth1
        address 192.168.1.2 <-- Set the IP address you want the Ubuntu Box to have on the network
        netmask 255.255.255.0
        gateway 192.168.1.1 <-- Set the IP address of the router for the network

That should have you set for IPv4. If you want to set a static IPv6 address, do something like:

auto eth7
iface eth7 inet static
       dns-nameservers 74.82.42.42
       address 192.168.7.1
       netmask 255.255.255.0
       up /sbin/ifconfig eth7 promisc

iface br0 inet6 static
       address 2001:db8:e89d:9ab6:1:e7c:e7c:e7c
       netmask 64
       gateway 2001:db8:e89d:9ab6:e7c::1

Press Ctrl-X to save, and that should have it set up. Reboot to apply the changes (again, that's the easiest way, not strictly necessary if you manually remove the current config before apply this one, but rebooting is easy. And you get to test that everything works after a restart).


You have FlashBlock extension.Disable it.


Keyboard layout is switched randomly in Ubuntu 14.04

Go to System Settings -> Text Entry. To the right you find a couple of options which you may want to change in accordance with your preferences.


The complete installation guide can be found here. (the installation instructions in the question is incomplete)
If you plan to uninstall mailcow-dockerized follow the Deinstallation guide:
docker-compose down -v --rmi all --remove-orphans


Windows already has a remote access system that you can use and connect using vinagre application available for Ubuntu.

Right click on My Computer > Properties > Remote tab

You just need to configure it and ask the network administrator to redirect the correct ports to you Windows computer.

The necessary port is TCP 3389, redirect connections on this port to your TCP 3389 port in your computer and you will be able to use the vinagre (installed by default on Ubuntu 11.10) to remotely connect.

If you do not want to install any extra software quicksharescreen.com should allow you to support a customer over a web based interface that run with Java.

Its still in beta fase but it should work.

Has an alternative you can use others, here is a list of sites that allow you to share a desktop over the web and are cross platform:

vyew
Google Remote Desktop
sharing
Java Remote Desktop


How do I run python code in ubuntu 14.04

Open a terminal by pressing CtrlAltT. If you remember where you saved the Python code file (say as first.py in the Desktop folder), use the following command to run it:

python2 ~/Desktop/first.py

If you're using Python 3.X replace python2 with python3 in the above command. On Ubuntu, python2 and python are the same, but it's always good practice to explicitly specify which version you're using.

You can also simply run python2 or python3 to get to an interactive shell. Another option is to use IPython Notebooks.


How to share screen/window with a remote user?

You can use TeamViewer for this. To install it go to: http://www.teamviewer.com/en/download/linux.aspx

Then install it using the following sequence of commands:

cd ~/Downloads
wget http://download.teamviewer.com/download/version_9x/teamviewer_linux.deb
sudo dpkg -i ~/Downloads/teamviewer_linux.deb
sudo apt-get -f install

If using Ubuntu 64bit then download teamviewer_linux_x64.deb and follow the above steps.


I think I understand what you mean. You want to generate a file based on the current user (or requested file). You currently do that over HTTPS but you want to also make it available over SFTP... Right? Interesting problem.

You might be shocked to hear that I don't think there's anything that can do what you're asking out of the box.... Anything's possible though.

My first approach involves writing your own filesystem!

I'd start with FUSE. Moreover, python-fuse. Here's the only tutorial I've ever used for FUSE. It'll get you to the point where you can start to edit things. I would:

Have it list just one [fake] file in readdir()
Work out how to find the username from the filesystem
Hotwire open() and read() to pull from a requests.get('your URL') using the username. open() might just need to be faked and read() be a handle on the requests request.
You'll probably need to patch up and dummy many of the other methods so they return data but it'll obviously be faked most of the time
Mount this FUSE filesystem somewhere in your SFTP that everybody can see as readonly

This would work for either sftp approach (you could look at the full path instead of the user, for example) but you'll need a single sftp account that people can log in with.

Alternatively, if every user has an account, you could try to monitor access to a directory owned by each user. inotifywatch and inotifywait can let you watch for access to a directory.

inotifywait -mrq --format '%w' /home/*/magicdir/ | while read DIR; do
    user=${DIR:6:-10}  # that is based on the length of /home/ and /magicdir/
    wget -qO $DIR https://path/to/items/${user}
done

And leave that running somewhere in the background. It'll update the file from the website everytime they access the directory. You might want to check it (with an echo blaaa $DIR) to make sure it's not hammering the server. It may not display a file the first time they load the directory.


MongoDB super-admin authenticates fine but still gets unauthorized query errors?

The userAdminAnyDatabase role (and the userAdmin role that it is an extension of) simply gives your user the permission to read and write to the system.users collection to administer the users of a database. It doesn't allow the user to read or write to the actual collections of the database. For that, you need to grant the read or readWrite roles.

See User Privilege Roles in MongoDB and Add a User to a Database.


Firefox upgrade breaks Ctrl-W and Ctrl-U keybindings

I believe I've found the problem; enabling all my plugins one at a time has revealed that the problem only exists with the (otherwise excellent) Vimperator plugin enabled.

Disabling Vimperator fixes the text area, text field, and input boxes ^W and ^U handling but at the cost of removing all the keyboard shortcuts I am familiar with. High cost.


Disable "Mouse battery low" spam notification

OK, I hit the same issue. Reasons are similar; my Logitech M570 is fed on "dead" batteries as it lasts MONTHS on a very low voltage alkaline. So I use batteries in other things and keep the dead ones for my M570.

The best answer I've found was to lower the Power Plugins critical level warning. This way you can customise when it nags.

You need dconf for command line or dconf-editor for the GUI version (for GUI you'll need to do sudo apt-get install dconf-tools, although that package may not be available for newer versions, so just get dconf-editor and its dependencies).

Setting is generically for batteries though, so if you're on a laptop or a UPS then you will be altering the warning levels for those, which may be non ideal.

For Ubuntu 17.10 (Artful Aardvark) go to org → gnome → settings-daemon → plugins → power. Alter the "percentage-low" setting to what you want. I changed from 10% to 4%.

It is not a perfect answer if you have a laptop, but it is fine for a desktop computer and better than filling landfill with batteries or being nagged.


rm libstdc++.so.6
rm libgcc_s.so.1

at the game folder


Stuck at Grub, can't boot Win7 installation USB

What Ubuntu version is it? The 14.04 installers have a known problem with UEFI boot. I wrote a guide on how to install 14.04 with UEFI boot here: How to install Ubuntu 14.04 64-bit with a dual-boot RAID 1 partition on an UEFI/GPT system?. You should be able to use the guide, ignoring the RAID stuff (everything referring to mdadm/RAID).


Is it possible to See my secondary screen as PIP on my primary one

Have you tried to clone your screens using arandr? You can install it by using this command:

sudo apt install arandr

Once you have it arandr allows you to overlap or arrange your displays in the way you want. You can also resize them to make them fit as need.


To 'fix' the error, I did the following:

Open a new terminal

sudo killall dpkg
sudo killall apt
sudo dpkg --configure -a
Ctrl-C on memtest86+ hang
Ctrl-C on initramfs install hang
sudo update-grub2

Then:

sudo nano /etc/default/grub

Add GRUB_DISABLE_OS_PROBER=true

Courtesy of: https://bugs.launchpad.net/ubuntu/+source/memtest86+/+bug/986833/comments/3

Reboot. No problems on reboot.


Cannot load plugins in current version of Calibre

Ctrl+c downloaded plugin file in Nautilus
Ctrl+v in "Load plugins from file" dialog window

For now, it's only solution to do it in GUI without using command-line solution ...


It turned out to be fixable by Boot Repair tool

But it's still weird i needed to use it on clean installation.


Run these commands in terminal :

32Bit

mv $HOME/.steam/ubuntu12_32/steam-runtime/i386/usr/lib/i386-linux-gnu/libstdc++.so.6 $HOME/.steam/ubuntu12_32/steam-runtime/i386/usr/lib/i386-linux-gnu/libstdc++.so.6.bak

64bit

mv $HOME/.steam/ubuntu12_32/steam-runtime/amd64/usr/lib/x86_64-linux-gnu/libstdc++.so.6 $HOME/.steam/ubuntu12_32/steam-runtime/amd64/usr/lib/x86_64-linux-gnu/libstdc++.so.6.bak

This solution may have solved steam errors like yours in other posts, e.g. this Post.
As it has not been marked as solved yet, please tell me if this works or not.


20.04 autoinstall ejecting iso after first reboot

If you want to stop the physical ejection, then I think you'd have to patch the /sbin/casper-stop script in the installation environmment.  If you simply want to avoid the prompt to "Please remove the installation medium, then press ENTER" then you can create the file /run/casper-no-prompt.  Either of these options could be done in early-commands of your autoinstall config.
autoinstall config like the following might work
early-commands:
    - sed -ie 's/eject -p/#eject -p/' /sbin/casper-stop
    - touch /run/casper-no-prompt

When the installer, subiquity, finishes and reboots, it simply runs /sbin/reboot.  This can be seen in the subiquity source code.
The installer environment will run /sbin/casper-stop during shutdown because of the systemd service defined in /lib/systemd/system/casper.service.  This script will display the prompt and eject the media.  The source code of the script shows that the prompt is configurable, but the eject command is called as long as the cdrom is mounted, and advertised as removable.
See also

https://unix.stackexchange.com/questions/528577/how-to-skip-please-remove-the-installation-medium-then-press-enter


"CRITICAL: We failed, but the fail whale is dead. Sorry..."

In this case the "fail whale" is an error message logged by GNOME if something went wrong. It's named after a illustration by Yiying Lu used by Twitter to display errors.

If it is dead it means that there's not enough of GNOME running to display the error.


LibreOffice will update through the added ppa by itself when a new version is available from the ppa. ppa:libreoffice/ppa has packages for Ubuntu 14.04-20.04.


Should I align partitions on an SSD, if so how do I do it at install time?

What advantages does it truly bring to have an aligned partition on a SSD?

Basically it's all about better performance. If it's really such a big deal with current generation SSDs - who knows, but aligning the partition won't hurt.

Anyways, Ubuntu's installer automatically aligns the partitions correctly. The first partition starts at sector 2048, that is after 2048 sectors á 512 Bytes = 1 MiB, and 1 MiB is evenly dividable by all common SSD block sizes.


Btrfs logical volume groups crash making the device unmountable

run "btrfs-find-root /dev/vg1/volume_1&> /mnt/iscsi/btrfs-find-root &"

parent transid verify failed on 887020683264 wanted 6011 found 6270
Ignoring transid failure
Couldn't setup extent tree
Couldn't setup device tree
Superblock thinks the generation is 6011
Superblock thinks the level is 1
Found tree root at 887014998016 gen 6011 level 1
Well block 448900530176(gen: 7903 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 777465511936(gen: 7844 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 503614685184(gen: 7412 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 470875013120(gen: 7343 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 470870278144(gen: 7341 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 471096754176(gen: 7063 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 471050649600(gen: 6927 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 558475149312(gen: 6774 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 886999793664(gen: 6567 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 886999777280(gen: 6567 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 470921674752(gen: 6291 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887014064128(gen: 6269 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887014031360(gen: 6269 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887014014976(gen: 6269 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887013965824(gen: 6269 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887013326848(gen: 6268 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887013294080(gen: 6268 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887013244928(gen: 6268 level: 0) seems good, but generation/level doesn't match, want gen: 6011 level: 1
Well block 887010803712(gen: 6267 level: 1) seems good, but generation/level doesn't match, want gen: 6011 level: 1
........


Lubuntu, broken fstab and non existent swap

I just created a 19.04 Lubuntu virtual machine. Based on its fstab it looks like you need a single line like this:

UUID=1124c007-a2cd-4e2b-8942-06fca94f5f88 /  ext4 defaults 0 1

Don't include that device info /dev/sda1


How do I remove Oracle Java 7 from Ubuntu 11.10

If you don't need ORACLE Java, you can switch to Icedtea Open JDK.
But to your problem:
To completely uninstall a package just type into an terminal

sudo apt-get purge PACKAGENAME

in fact of Oracle java it's

sudo apt-get purge oracle-java7-installer

and then install jre6 again

sudo apt-get install openjdk-6-jdk

Are you sure, you have Oracle Java installed? Because from Ubuntu 10.10 the Oracle Java isn't a part of the package-sources anymore... Did you install it manually?


How should I handle ABI incompatability between gcc-4.9 and gcc-5?

The problem you have is related to C++11 standard requiring a different implementation of C++ string (and list) type(s). For compatibility, g++5.2 and above compiles the new C++11 compliant type by default, (whether or not you specify -std=c++11), but you can set the macro

-D_GLIBCXX_USE_CXX11_ABI=0

to revert to the old C++ string type. New libstdc++ implementation contain both ABIs. So if you have binaries you have to link against with the old non-compliant ABI, you must set the macro above on your g++ compiles. This should produce binaries compatible with the old ABI.

Unfortunately if you are using libraries from the OS other than the C++ Standard Libraries, then unless these libraries are multi-arch in the sense of providing all functions which differ by ABI in both ABI's, then you're screwed because they'll probably only have the new ABI.

Having said that I have a problem on an old Ubuntu downloading an untrusted modern g++ which simply refuses to produce the new ABI. So it seems that backport from ppa:ubuntu-toolchain-r/test is in fact badly broken because it refuses to produce binaries according to the new ABI.

Anyhow the bottom line is when you link together everything must either be the old ABI or the new ABI. The following will tell which you are using:

g++ --version
echo '#include <string>' > test.cpp
echo 'void f(std::string s) {}' >> test.cpp
cat test.cpp
g++ -std=gnu++11 -c -o test.o test.cpp
nm test.o | c++filt

If that has

std::basic_string<char, ....

in it, its the old ABI. If it has

std::__cxx11::basic_string<char, ...

in it, its the new ABI.


Google Chrome Black Screen in Xubuntu 14.04

Try disabling GPU compositing on all pages  from the setting available on chrome://flags/ and see if it works. Hope this helps!


How can I tell what package requires a reboot of my system?

Short version:

cat /var/run/reboot-required.pkgs

Explanation:

Looks like there is an easy way to automatically extract the requested information.

Inside .deb files there are control files for installation, including postinst (run after installation).

For example, in linux-image-2.6.35-25-generic_2.6.35-25.44_amd64.deb,
 postinst includes

my $notifier          = "/usr/share/update-notifier/notify-reboot-required";

my $warn_reboot     = 'Yes';     # Warn that we are installing a version of
                                 # the kernel we are running

and

# Warn of a reboot
if (-x $notifier) {
 system($notifier);
}

The shell script
/usr/share/update-notifier/notify-reboot-required updates
 /var/run/reboot-required and /var/run/reboot-required.pkgs.

The latter file contains a list of packages requesting a reboot.


Getting 4k working on Haswell graphics for AOC U2868PQU

Solved: the problem was the cable, new cable, no problems.


How to install Samsung AllShare or recommendations for other DNLA Server options?

You cannot install AllShare on linux without wine but I would not recommend that at all.

Why don't you try using a better DLNA server like Serviio?

It's free, works great with my Samsung TV, has more file format support then AllShare and does the job on the background not bothering you.

I mentioned Serviio but there are a bunch of free DLNA servers out there. Do a Google search on DLNA servers and choose one. Start with Serviio tough, it's recommended.


There is several way to connect to a remote Linux machine.

Shell access
You can use ssh: in a local terminal, use ssh login@host and you got a remote terminal.

Single window access
Just add -X option to ssh to enable X11 Forwarding : like in 1, you'll have a terminal on the remote host, but any graphical application that you launch on your term will be displayed locally. IMHO, this is the best option.

Whole desktop access
You can use a vnc client like vinegar.

There is also other protocols but some are really old (xdmcp), and other may be too young (nx).


It's possible to develop ubuntu touch app in C++ without using QML?

Ubuntu definitely has support for Qt, considering that it's built almost entirely using it. QML is the C++ tool that developers use to make the application development easier.

Ubuntu touch has OpenGL support, as you can see here.


Find & Delete duplicated files on multiple harddisks at once

The script below looks for duplicate files in up to 10 directories at once, looking for duplicates in the combined directories.

It should be dramatically faster than both fdupes (running fdupes -r) and fslint; on a relatively small directory of 40GB, locally stored, it took the script 5 seconds to create a dupe list, while it took fdupes and fslint much longer (~ 90 / 100 seconds). On a larger directory (700GB, ~350000 files) on a relatively slow external USB drive, it took 90 minutes. With fdupes it would have been over 200-250 minutes, looking at the progress indication (which is nice, the script below doesn't show the progress), but I didn't wait for it all the way.
I should mention that for example fslint offers additional functionality, which the script does not (as it is), so the comparison is strictly on creating the dupes list.

Furthermore, the speed depends for a part on how fast the disk reads: I tested several media (a.o on a network drive) with huge differences, especially on smaller directories, where creating the file list takes a relatively great part of the job ('s time).

The bottom line is that it won't be a quick job either which way, you might ask yourself if the directories aren't too large.

How it works

When the script finds duplicates, the duplicates are listed as follows:

Creating file list... /home/jacob/Bureaublad/test2
Creating file list... /home/jacob/Bureaublad/foto
Creating file list... /home/jacob/Bureaublad/Askubuntu
Checking for duplicates (10790 files)...
------------------------------------------------------------
>  found duplicate: test1.txt 2

/home/jacob/Bureaublad/test2/test1.txt
/home/jacob/Bureaublad/test2/another directory/test1.txt
------------------------------------------------------------

and so on

The script

#!/usr/bin/env python3

import os
import sys

total_filelist = []
total_names = []

def find_files(directory):
    l = []; l2 = []
    for root, dirs, files in os.walk(directory):
        for file in files:
            l.append(file)
            l2.append(root+"/"+file)
    return (l, l2)

i = 1
while i <= 10:
    try:
        dr = (sys.argv[i])
        print("Creating file list...", dr)
        total_filelist = total_filelist+find_files(dr)[1]
        total_names = total_names+find_files(dr)[0]
        i = i+1
    except IndexError:
        break

print("Checking for duplicates ("+str(len(total_names)),"files)...")

for name in set(total_names):
    n = total_names.count(name)
    if n > 1:
        print("-"*60,"\n>  found duplicate:",
              name, n, "\n")
        for item in total_filelist:
            if item.endswith("/"+name):
                print(item)

print("-"*60, "\n")

Copy it into an empty file, save it as find_dupes.py and run it by the command:

python3 <script> <directory1> <directory2> <directory3>

Up to max 10 directories

More options of the script

It is relatively simple to add additional functionality; move duplicates to another directory for example, renaming etc, so you can either manually or automatically decide which file to keep.

How to make the job doable

Your directories seem huge. To make the job reasonably possible, there is another, more sophisticated way to prevent the system from "choking": instead of doing the job on all file types (extensions) at once, you could cut the job into sections per file type. A small test on a directory of 30.000 files reduced the time from appr. 20 seconds (all files) to 0.3 second for one extension.

To make the script look for duplicates of only one file type, replace the section of the script:

def find_files(directory):
    l = []; l2 = []
    for root, dirs, files in os.walk(directory):
        for file in files:
            l.append(file)
            l2.append(root+"/"+file)
    return (l, l2)

by:

def find_files(directory):
    l = []; l2 = []
    for root, dirs, files in os.walk(directory):
        for file in files:
            if file.endswith(".py"): # example .py extension
                l.append(file)
                l2.append(root+"/"+file)
    return (l, l2)

Finding occurring file extensions

To list all occurring file extension in a directory, you can use the script below:

#!/usr/bin/env python3

import sys
import os

l = []
for root, dirs, files in os.walk(sys.argv[1]):
    for f in files:
        if (
        f.startswith("."),
        f.count(".") == 0,
        f.endswith("~"),
        ) == (False, False, False):
            l.append(f[f.rfind("."):])
for item in set(l):
    print(item)

Copy it into an empty file, save it as find_extensions.py and run it by the command:

python3 <script> <diretory>

Example ouput:

.txt
.mp3
.odt
.py
.desktop
.sh
.ods


Solution given by OP:

  12.04 does not have the needed kernel module snd-usb-hiface this is introduced in the 3.11.1 kernel and installing that on 12.04 gives USB sound for my equipment. How to install the 3.11.1 kernel is given here:- installing 3.11.1 kernel


There is a project (as @Rinzwind indicated) on Launchpad which looks like it attempted to produce a native KDE client - It was part of the Google Summer Of Code project.

Unfortunately, the associated PPA has been removed and the alpha-software which exists as a tar file has not been updated since August last year.  The assumption therefore is that the project is either in an extensive lull or has been abandoned.

The software itself in the tar file I have found nigh-impossible to compile.

My suggestion therefore would have been to install ubuntuone-control-panel-gtk - this gives you a GTK type interface for Ubuntu-One.

However this package is only available for Maverick and Natty.  It hasnt been backported to Lucid.  There is one potential PPA available with this package backported.  However, as the author himself says - use with care.  Therefore - take the authors advice and backup first using a good backup tool such as Clonezilla

To Install on Lucid/Maverick

sudo add-apt-repository ppa:kalon33/experimental-stuff
sudo add-apt-repository ppa:ppa:kalon33/ppa
sudo apt-get update
sudo apt-get install ubuntuone-control-panel-gtk

NOW VERY IMPORTANT

Open your software sources and untick both the Kalon33 experimental PPA and Kalon33 PPA.  The reason is that you probably will not want any of the authors extensive builds for Lucid/Maverick.

Finish off running

sudo apt-get update

Running UbuntuOne

The package will install Ubuntu-One under the Settings menu.


Will any programs be removed from my current install if I switch to Ubuntu?

All your programs will be removed, just everything. Of course instead of deleting Windows completly, you can have both, Windows and Ubuntu, then your Windows' data will remain, although notice that Ubuntu and Windows are different Operational Systems (OSs).

Programs that run on Windows are made in its code, so when you get Ubuntu you will need programs for Ubuntu's code, some Windows applications are available for Ubuntu too, although many not, and for that cases there are "equivalents" in Ubuntu.

You should learn more about Ubuntu before installing it in its official webpage. Just a hint for you, in case your work depend on professional and specific features of tools like Autodesk, MS Office, Visual Basic, etc. You almost certainly will be doing a bad movement as you will need time to learn how to do the same work with the different Ubuntu's apps, and there are cases in which you may need very, very specific tools and features that may not be available in Ubuntu.

Last but not least, I am not saying you: "Hey, its bad turning to Ubuntu"; the OS is great, although you need to confirm, before installing it, if you will be able to accomplish your tasks in the new environment. If you just use the PC for web, video, music, reading and common tasks, then I will say to you: Why haven't you tried Ubuntu yet?


How to uninstall Gnome theme (including the GNOME Classic)?

You can uninstall Gnome Classic by executing sudo apt-get remove gnome-session-fallback.


Default Firefox browser not playing some content

I had the same issue and after running the following command :

sudo apt install ffmpeg

It's a big install just for playing videos in firefox, but at least it works, and having ffmpeg on your system might always be useful.


Running game server from bash without waiting for input

You may try to write a newline (\n) character to the standard input before running the server.

This is an example that write "foo" and pipes it to the std.in of the next command

echo $'foo' | while read x ; do echo $x ; done

So in your case you could do

echo $'\n' | ./samp03svr

Newline quoting example taken from here.


How to change unity side laucher position from left to right ubuntu 14.04

You cannot move the launcher itself.

Here is the comment on a bug about it

But you can make it look like with Cairo dock.

sudo apt-get install cairo-dock

Now you can play around with configurations and move the dock to the right.

Make Unity's launcher auto-hide and you have a launcher (actually not launcher, it is dock ) on the right.

I like Ubuntu for its customizability. Do you?


Solved. In a situation like this , all related scripts must be checked : /etc/logrotate.conf , /etc/cron.daily/logrotate and /etc/logrotate.d/mysql .
For me the issue was in /etc/logrotate.d/mysql , with the flush-logs commmand, the user wasn't allowed to run that command,


file readable and writeable by the web server

in your attempt:

sudo chgrp apache /var/www/html/itdb/data/itdb.db

you're setting group "apache" as owner of this resource

/var/www/html/itdb/data/itdb.db

and script is complaining:

var/www/html/itdb is not writeable by apache

and even giving you solution:

chown www-data /var/www/html/itdb/data/files/; chmod u+w /var/www/html/itdb/data/files/

(probably you might want to run those with sudo to ensure success)

Good luck


Broadcom LY-PHY WLAN card does not work in 14.04.1 on HP Mini 210

This normally works sudo apt-get purge bcmwl-kernel-source broadcom-sta-common broadcom-sta-dkms and sudo apt-get install firmware-b43-installer and reboot
https://www.dropbox.com/s/7exlzch25ap6uha/b43.zip?dl=0

And copy the files to /lib/firmware/b43


How exactly does Synaptic keep track of "New in repository" packages?

If I'm not mistaken the files you are looking for are:

/var/cache/apt/pkgcache.bin
/var/cache/apt/srcpkgcache.bin

This is a local package database for binary and source packages respectively. It is updated every time you run apt-get update or programs like Synaptic do that somehow.


Why "Disks" and "Startup Disk Creator" utilities don't work on Ubuntu 14.04 LTS?

I strongly recommend you try using Gparted. It's considered by many to be a standard, highly stable / respected tool for formatting drives. This command will install it if you don't have it:

sudo apt-get install gparted

Now follow the steps:

Ensure you select the correct drive:

In GParted, select the flash drive from the dropdown menu in the top right corner.
Then select "Device" > "Create Partition Table". Choose MBR/DOS. After that you can format it...
Right click to unmount it. This allows you to change things on the disk because it stops the system from using it.
Once you have it unmounted, right clicking on it will show you the Format To option. You can choose whatever type of file system you want on the disk.
Click Apply

To do this with more pictures and info, try looking at my source here.

Personally, I don't think you can say Linux is "better" than Windows because it's to complicated to make a straight comparison. I happen to far favor Linux and Linux has many strengths that Windows does not. However, as with everything, when you come to something new you might need to learn about your new toolset before you can work as easily.

Gparted is part of your new toolset.

Finally, you might be able to fix the bug in the tools you tried to used with an update. From launchpad:

  This bug was fixed in the package udisks2 - 2.1.3-2git1ubuntu1

You can update your system with sudo apt-get update then sudo apt-get upgrade.


how to discover all WiFi networks on my Ubuntu 15.10 and choose one of them?

Use iwlist. The man page (actually http://manpages.ubuntu.com/manpages/wily/en/man8/iwlist.8.html) says:

wlist.8.gz
Provided by: wireless-tools_30~pre9-8ubuntu1_i386

NAME

       iwlist  -  Get  more  detailed  wireless  information  from  a wireless
       interface

SYNOPSIS

       iwlist [interface] scanning

snip...

PARAMETERS

       scan[ning]
              Give the list of Access Points and Ad-Hoc cells  in  range,  and
              optionally  a  whole  bunch  of  information  about them (ESSID,
              Quality, Frequency, Mode...). The type of  information  returned
              depends on what the card supports.
              Triggering  scanning  is  a privileged operation (root only) and
              normal users can only read left-over scan results.  By  default,
              the way scanning is done (the scope of the scan) is dependant on
              the card and card settings.
              This command takes optional arguments, however most drivers will
              ignore  those.  The  option essid is used to specify a scan on a
              specific ESSID. With  some  card/driver,  this  enables  to  see
              hidden  networks.  The  option  last does not trigger a scan and
              read left-over scan results.

"How do I connect to a wireless..." is a second question that should be asked by itself, in a different Question post.


Put emblem on folder icon if it contains particular file/subdirectory

Intorduction

NOTE: this is a new and updated version of the script, for old version see the edit history of this answer

The script presented below allows to either set a github repository icon or emblem (but not both), as well as reset that metadata back to default. Usage is very simple, as explained by the -h option:

$ ./set_folder_icon.py -h
usage: set_folder_icon.py [-h] [-i ICON] [-e EMBLEM] [-r ROOT] [-u]

Finds and sets github repository icons.Choose either --icon or --emblem.
Without either the script exists with 0 exit status.For --icons, use absolute
or relative path.For --emblem use single string of text.Emblem pathnames are
in the format emblem-name.extension.The script then can becalled with -e
<name>.Use ~/.local/share/icons folder for custom emblems (if it does not
exist - create it. Store filenames in specified format

optional arguments:
  -h, --help            show this help message and exit
  -i ICON, --icon ICON  path to image to set
  -e EMBLEM, --emblem EMBLEM
                        single-string emblem name
  -r ROOT, --root ROOT  where search starts,default - current working
                        directory
  -u, --unset           unset both emblem and icon. Cannot be used with -e or
                        -i options

So if we wanted to recursively search home folder  for all github repositories and set their emblem, we'd do set_folder_icon.py -e myemblemname -r $HOME or just cd; set_folder_icon.py -e myemblemname

For best performance, please create ~/bin directory and store the script there as set_folder_icon.py. If you want to use it immediately, run source ~/.bashrc. If you're using a different shell, ensure that your ~/bin is added to $PATH variable.

NOTE: The script can take any arbitrary file with --icon option, but --emblem requires you to have a specific file to be stored in ~/.local/share/icons with filename something like emblem-github. See the The script in action section for an example

The script in action

I happen to keep all my github repositories under ~/GIT folder. In the screenshots below you can see how all github repositores get their emblem set to the custom one.

Before:

After:

Script

The script is also available on my personal GitHub repository , where it is more likely to get newer changes and fixes.

#!/usr/bin/env python3
"""
Author: Sergiy Kolodyazhnyy
Date: 7/12/2017
Purpose: Script to find github repository folders
         and set their icons for Ubuntu.
Written for: https://askubuntu.com/q/935003/295286
"""
import argparse
import os
import sys
import subprocess
import urllib.parse

def puke(message, status_code):
    """ Print to stderr and exit with given code """
    sys.stderr.write('>>> OOOPS. Something is wrong:\n')
    sys.stderr.write(message + '\n')
    sys.exit(status_code)

def run_cmd(cmdlist):
    """ Reusable function for running external commands """
    try:
        stdout = subprocess.check_output(cmdlist)
    except subprocess.CalledProcessError as cpe:
        puke('Called command failed with ' + str(cpe.returncode) +
             ' exit status\n' + repr(cpe), 4)
    else:
        if stdout:
            return stdout

def set_icon(directory, icon_type, image):
    """ Wrapper function that specifies command and calls run_cmd()"""
    key = 'metadata::' + icon_type
    meta = {'metadata::custom-icon': 'string',
            'metadata::emblems': 'stringv'}

    # Because custom-icons and emblems type are mutually
    # exclusive, we need to unset custom-icon to enable emblems
    if icon_type == 'emblems':
        cmd = ['gvfs-set-attribute', '-t', 'unset',
               directory, 'metadata::custom-icon']
        run_cmd(cmd)

    cmd = ['gvfs-set-attribute', '-t', meta[key],
           directory, key, image]
    return run_cmd(cmd)

def unset_all(directory):
    for key in ['metadata::custom-icon', 'metadata::emblems']:
        run_cmd(['gvfs-set-attribute', '-t', 'unset', directory, key])

def find_directories(tree_root):
    """ Does the job of recursive traversal of given directory tree,
        starting at the specified tree root directory. If condition for
        given subdirectory is met, calls set_icon() function"""
    for current_dir, subdirs, files in os.walk(tree_root):
        # This check can be adapted to other cases
        if '.git' in subdirs:
            print('Found', current_dir)
            yield current_dir

def parse_args():
    """ Parses command-line arguments """

    text = ['Finds and sets github repository icons.',
            'Choose either --icon or --emblem. Without either'
            ' the script exists with 0 exit status.',
            'For --icons, use absolute or relative path.',
            'For --emblem use single string of text.',
            'Emblem pathnames are in the format',
            ' emblem-name.extension.', 'The script then can be',
            'called with -e <name>.Use ~/.local/share/icons folder',
            ' for custom emblems (if it does not ',
            'exist - create it. Store filenames in specified format']

    arg_parser = argparse.ArgumentParser(description="".join(text))
    arg_parser.add_argument('-i', '--icon', help='path to image to set',
                            type=str, required=False)
    arg_parser.add_argument('-e', '--emblem', help='single-string emblem name',
                            type=str, required=False)
    arg_parser.add_argument('-r', '--root', help='where search starts,' +
                            'default - current working directory',
                            default='.', type=str, required=False)
    arg_parser.add_argument('-u', '--unset', help='unset both emblem ' +
                            'and icon. Cannot be used with -e or -i options',
                            action='store_true', required=False)
    return arg_parser.parse_args()

def main():
    """ Script entry point """
    # Parse command-line arguments and check their correctness
    args = parse_args()
    status_code = {'icon_missing': 1, 'root_missing': 2,
                   'root_isnt_dir': 3, 'exclusion': 4,
                   'not_string': 5, 'conflict': 6}

    if args.unset and (args.icon or args.emblem):
        puke('Conflicting options', status_code['conflict'])
    if not args.unset:
        # both or none are given
        if not args.icon and not args.emblem:
            sys.exit(0)
        if args.icon and args.emblem:
            puke('Can only use either --icon or --emblem',
                 status_code['exclusion'])
        # Verify correctness of either one
        if args.icon and not os.path.exists(args.icon):
            puke('Icon pathname does not exist',
                 status_code['icon_missing'])
        if args.emblem:
            if '/' in args.emblem:
                puke('Emblem must be a single string of text,no paths',
                     status_code['not_string'])
            if not isinstance(args.emblem, str):
                puke('Given argument for emblem is not a string',
                     stats_code['not_string'])

        # Verify correctness of the path
        if not os.path.exists(args.root):
            puke('Root pathname does not exist',
                 status_code['root_missing'])
        if not os.path.isdir(args.root):
            puke('Root pathname is not a directory',
                 status_code['root_isnt_dir'])

    if args.unset:
        for directory in find_directories(args.root):
            print('Unsetting', directory)
            unset_all(directory)
        sys.exit(0)

    # Everything should be OK past this point

    if args.icon:
        meta_type = 'custom-icon'
        icon = 'file://' + urllib.parse.quote(os.path.abspath(args.icon))
    if args.emblem:
        meta_type = 'emblems'
        icon = args.emblem

    # Now do the actual traversal and icon-setting
    for directory in find_directories(args.root):
        set_icon(directory, meta_type, icon)

if __name__ == '__main__':
    main()

Automating the script

Of course, we can run the script manually each time (in fact I'd likely make a function that can combine git clone and running this script), although I would recommend that you make the script run each time you log into your GUI session. In order to do that, open the Startup Applications menu, and add the script ( using full path and full filenames is recommended ) as an entry.

And next time you log-in your icons will be set.

As for manual idea, you could run git clone and  the script one after the other with && operator, or better yet make a function in ~/.bashrc for that like so:

$ tree
.

0 directories, 0 files
$ typeset -f my_gitclone
my_gitclone ()
{
    git clone "$1" && ~/GIT/sergrep/set_folder_icon.py -e github
}
$ my_gitclone https://github.com/SergKolo/sergrep
Cloning into 'sergrep'...
remote: Counting objects: 387, done.
remote: Compressing objects: 100% (17/17), done.
remote: Total 387 (delta 10), reused 17 (delta 5), pack-reused 365
Receiving objects: 100% (387/387), 115.65 KiB | 0 bytes/s, done.
Resolving deltas: 100% (203/203), done.
Checking connectivity... done.
Found ./sergrep


Wireless LAN connection doesn't work on Ubuntu 12.10, how to fix it?

Ok, first turn your router off and on again. If that doesn't help press Ctrl-Alt-t. A terminal will pop up, run:

sudo service network-manager restart

You'll be prompted for your password, as you type it in there's no feedback; that's normal. Press enter.

If that doesn't solve the issue, edit your question and post the output of the following terminal commands:

lspci -v | grep -iA 10 'network'

lsmod

rfkill list all

sudo lshw -c network

iwconfig

min info for now:

lspci - v | grep -iA 10 'network': Device name after "Network controller:", "Kernel driver in use:", "Kernel Modules"

lsmod: check if the Kernel driver from lspci appears in the output

rfkill list all: For Wireless LAN does it say Soft blocked: yes or Hard blocked: yes, anywhere?

don't post that info in the comments below, but edit your question and post it there.

try this in the terminal:

sudo rmmod -f dell-laptop

then

sudo rfkill unblock all

rfkill list all

does it say "blabla blocked: yes" anywhere

check wifi connection again.

Report back


Using XWinWrap on startup for desktop image covers taskbar in 12.04

Also using Ubuntu 12.04 I use XWinWrap with the geometry (-g) option to maximize the screen other wise I've found I lose my taskbar icons as well. These are the options I use for the Electric sheep screensaver.

xwinwrap -ni -o 0.4 -s -st -sp -b -nf -g 1440x900 -- /usr/bin/electricsheep -window-id WID

You can try removing the -fs option and adding in -g for your display resolution.


can't run this shell script (get-sh1t-done)

As Lekensteyn pointed out in the comment above, you should export the PATH in the .bashrc  in the user's home directory like so:

PATH="$HOME/Documents/icambridge-get-sh1t-done-1222b6b:$PATH"

Then run source ~/.bashrc or restart your terminal for it to take effect.

Running the command like sudo ./get-sh1t-done will only work if you are in the same directory as the file. Once you've correctly exported the PATH, you can simply run it as sudo get-sh1t-done

The error /usr/bin/env: php: No such file or directory is telling you that you need to install PHP. You can install it with:

sudo apt-get install php5-cli


There's no policy on when PPAs ever freeze or when you can create one, so it's really up to you.


Intel-microcode package upgrade in ubuntu 18.04 leads to unbootable system

When the meltdown and spectre virus potential was first discovered (but no actual virus) the first patches in early 2018 also broke the microcode.
The microcode is loaded before grub boots the kernel during the initramfs stage but you can also tell the kernel not to run the code until the microcode is fixed. This may or may not give you microcode updates and still run the kernel. You would need to update your grub command line with these options:
nopti nospectre_v2 nospec

nopti How to disable Page Table Isolation to regain performance lost due to Intel CPU security hole patch?
nospectre_v2 HOWTO make Linux run blazing fast (again) on Intel CPUs
nospec Can I disable the intel spectre fixes?

These three grub options are what I use but the middle link above has even more options to consider.
I'm not suggesting you disable your meltdown/spectre kernel options for speed but rather in order to use your microcode.
The other option is to roll back your microcode to a version prior to the bug. You can only discover if this is possible by trial and error:

Where to find older source&binary package versions?


Static IP on LAN and DHCP on WLAN on Ubuntu 16.04

Your wireless card will not know which access point to connect to among the many that are possibly available within scan distance and, more importantly, which you deem secure, unless you declare it along with the password.

I suggest that you amend the interfaces file to something like this:

auto lo
iface lo inet loopback

auto enp1s0
iface enp1s0 inet static
address 192.168.178.202
netmask 255.255.255.0
gateway 192.168.178.1
dns-nameservers 192.168.178.1

auto wlp2s0
iface wlp2s0 inet dhcp
wpa-ssid your_router
wpa-psk your_secret_password

Restart the interface and see if you connect:

sudo ifdown wlp2s0 && sudo ifup -v wlp2s0

The -v for verbose should produce output that tells you if you connected.


Will my situation allow me to retain my Windows license on this computer? Just in case I mess something up

The next microsoft thread answers your question:

Question:

  I recently Installed ubuntu on my laptop and cleared the disc on my pc
  when doing so. Microsoft account still has my laptop listed in the
  devices page.

  Is there any way of Installing windows 10 back without buying it?

Answer:

  Since your laptop is still listed under Devices in your Microsoft
  account, you can perform a clean install or reinstall Windows 10
  without the need of paying for it. This ensures a fresh copy of the
  operating system. See this Forum Article by Greg Carmack - Windows MVP
  for instructions and more information. Note that doing a clean install
  will delete all data on your PC.


device-mapper: remove ioctl on luks-xxxx failed: Device or resource busy

After two years of fighting with this, I think I've finally cracked it completely!

dmsetup ls gives you the data you need:

$ sudo dmsetup ls
luks-xxxxx (252:1)

then

sudo lsof |grep 252,1

It seems that sudo may be critical here -- at least in some cases.

This should give you the information necessary to close all open files on the device -- including names of open files and process IDs for the offending applications.  You may be able to simply go to those apps and close them, but a brute force approach might be something like:

kill -9 (process ID)

Once you've closed all the files, some of the command-line tools shown in the question may be necessary in order to close down the existing mount before it can be reopened normally.


When will chrome support WebGL on Linux?

It already does.

As ohaal commented, it's already supported.

  Supported operating systems

  Windows Vista/ Windows 7/ Windows 8 (Windows 7 or later recommended)
  Mac OS 10.6 or later
  Linux
  Chrome OS

  [...]

  Check to see if WebGL is enabled by by navigating to chrome://gpu/ in your Chrome browser.

Try out some of the demos to see how it performs.


you could try

sudo grub-install /dev/sda2

Or you could try using liveCD or USB to use boot-repair
https://help.ubuntu.com/community/Boot-Repair


As of now, the best solution I found is the Adobe Reader DC snap, which uses wine:
https://snapcraft.io/acrordrdc . Only, take care of not disconnecting the network for this snap, as the installer suggests doing to avoid updates (possibly not working), because this obviously prevents signature verification.

I have been trying the "native" Adobe Reader 9, Master PDF Editor and PDF Studio Viewer but I found them incomplete. Adobe Reader 9 apparently has an outdated verification method, Master PDF Editor appears to verify the signature but still shows a "?" rather than a "Valid signature" mark in my PDF, and PDF Studio Viewer marks the (supposedly valid) signature as Invalid because of not supporting the signature handler (Adobe.PPKLite::ETSI.RFC3161).

This is based on PDFs from only one authority, but for non-experts in digital signatures and certification methods, it appears that the snap is the best option if one only wants to verify a signature and go on.


How do I prepare MAAS to serve images on OpenStack?

Preparing MAAS for Juju and OpenStack using Simplestreams

When Juju bootstraps a cloud, it needs two critical pieces of information:

The uuid of the image to use when starting new compute instances.
The URL from which to download the correct version of a tools tarball.

This necessary information is stored in a json metadata format called "simplestreams". For supported public cloud services such as Amazon Web Services, HP Cloud, Azure, etc, no action is required by the end user. However, those setting up a private cloud, or who want to change how things work (eg use a different Ubuntu image), can create their own metadata, after understanding a bit about how it works.

The simplestreams format is used to describe related items in a structural fashion. See the Launchpad project lp:simplestreams. Below we will discuss how Juju determines which metadata to use, and how to create your own images and tools and have Juju use them instead of the defaults.

Basic Workflow

Whether images or tools, Juju uses a search path to try and find suitable
metadata. The path components (in order of lookup) are:

User supplied location (specified by tools-metadata-url or image-metadata-url config settings).
The environment's cloud storage.
Provider specific locations (eg keystone endpoint if on Openstack).
A web location with metadata for supported public clouds - https://streams.canonical.com

Metadata may be inline signed, or unsigned. We indicate a metadata file is signed by using the '.sjson' extension. Each location in the path is first searched for signed metadata, and if none is found, unsigned metadata is attempted before moving onto the next path location.

Juju ships with public keys used to validate the integrity of image and tools metadata obtained from https://streams.canonical.com. So out of the box, Juju will "Just Work" with any supported public cloud, using signed metadata. Setting up metadata for a private (eg Openstack) cloud requires metadata to be generated using tools which ship with Juju.

Image Metadata Contents

Image metadata uses a simplestreams content type of "image-ids". The product id is formed as follows:

com.ubuntu.cloud:server:<series_version>:<arch>

For Example:

com.ubuntu.cloud:server:14.04:amd64

Non-released images (eg beta, daily etc) have product ids like:

com.ubuntu.cloud.daily:server:13.10:amd64

The metadata index and product files are required to be in the following directory tree (relative to the URL associated with each path component):

<path_url>
  |-streams
      |-v1
         |-index.(s)json
         |-product-foo.(s)json
         |-product-bar.(s)json

The index file must be called "index.(s)json" (sjson for signed). The various product files are named according to the Path values contained in the index file.

Tools metadata uses a simplestreams content type of "content-download". The product id is formed as follows:

"com.ubuntu.juju:<series_version>:<arch>"

For example:

"com.ubuntu.juju:12.04:amd64"

The metadata index and product files are required to be in the following directory tree (relative to the URL associated with each path component). In addition, tools tarballs which Juju needs to download are also expected.

  |-streams
  |   |-v1
  |      |-index.(s)json
  |      |-product-foo.(s)json
  |      |-product-bar.(s)json
  |
  |-releases
      |-tools-abc.tar.gz
      |-tools-def.tar.gz
      |-tools-xyz.tar.gz

The index file must be called "index.(s)json" (sjson for signed). The product file and tools tarball name(s) match whatever is in the index/product files.

Configuration

For supported public clouds, no extra configuration is required; things work out-of-the-box. However, for testing purposes, or for non-supported cloud deployments, Juju needs to know where to find the tools and which image to run. Even for supported public clouds where all required metadata is available, the user can put their own metadata in the search path to override what is provided by the cloud.

User specified URLs

These are initially specified in the .juju/environments.yaml file (and then subsequently copied to the jenv file when the environment is bootstrapped). For images, use image-metadata-url; for tools, use tools-metadata-url. The URLs can point to a world readable container/bucket in the cloud, an address served by a http server, or even a shared directory which is accessible by all node instances running in the cloud.

Assume an Apache http server with base URL https://juju-metadata , providing access to information at <base>/images and <base>/tools . The Juju environment yaml file could have the following entries (one or both):

tools-metadata-url: https://juju-metadata/tools
image-metadata-url: https://juju-metadata/images

The required files in each location is as per the directory layout described
earlier. For a shared directory, use a URL of the form file:///sharedpath.

Cloud storage

If no matching metadata is found in the user specified URL, environment's cloud storage is searched. No user configuration is required here - all Juju environments are set up with cloud storage which is used to store state information, charms etc. Cloud storage setup is provider dependent; for Amazon and Openstack clouds, the storage is defined by the "control-bucket" value, for Azure, the "storage-account-name" value is relevant.

The (optional) directory structure inside the cloud storage is as follows:

  |-tools
  |   |-streams
  |       |-v1
  |   |-releases
  |
  |-images
      |-streams
          |-v1

Of course, if only custom image metadata is required, the tools directory will not be required, and vice versa.

Note that if juju bootstrap is run with the --upload-tools option, the tools and metadata are placed according to the above structure. That's why the tools are then available for Juju to use.

Provider specific storage

Providers may allow additional locations to search for metadata and tools. For OpenStack, Keystone endpoints may be created by the cloud administrator. These are defined as follows:

juju-tools the  value as described above in Tools Metadata Contentsproduct-streams the <path_url> value as described above in Image Metadata Contents

Other providers may similarly be able to specify locations, though the implementation will vary.

This is the default location used to search for image and tools metadata and is used if no matches are found earlier in any of the above locations. No user configuration is required.

There are two main issues when deploying a private cloud:

Image ids will be specific to the cloud.
Often, outside internet access is blocked

Issue 1 means that image id metadata needs to be generated and made available.

Issue 2 means that tools need to be mirrored locally to make them accessible.

Juju tools exist to help with generating and validating image and tools metadata. For tools, it is often easiest to just mirror https://streams.canonical.com/tools . However image metadata cannot be simply mirrored because the image ids are taken from the cloud storage provider, so this needs to be generated and validated using the commands described below.

The available Juju metadata tools can be seen by using the help command:

juju help metadata

The overall workflow is:

Generate image metadata
Copy image metadata to somewhere in the metadata search path
Optionally, mirror tools to somewhere in the metadata search path
Optionally, configure tools-metadata-url and/or image-metadata-url

Image metadata

Generate image metadata using

juju metadata generate-image -d <metadata_dir>

As a minimum, the above command needs to know the image id to use and a directory in which to write the files.

Other required parameters like region, series, architecture etc. are taken from the current Juju environment (or an environment specified with the -e option). These parameters can also be overridden on the command line.

The image metadata command can be run multiple times with different regions, series, architecture, and it will keep adding to the metadata files. Once all required image ids have been added, the index and product json files can be uploaded to a location in the Juju metadata search path. As per the Configuration section, this may be somewhere specified by the image-metadata-url setting or the cloud's storage etc.

Examples:

image-metadata-url

upload contents of to http://somelocation
set image-metadata-url to http://somelocation/images

Cloud storage

If run without parameters, the validation command will take all required details from the current Juju environment (or as specified by -e) and output the image id it would use to spin up an instance. Alternatively, series, region, architecture etc. can be specified on the command line to override the values in the environment config.

Tools metadata

Generally, tools and related metadata are mirrored from https://streams.canonical.com/tools . However, it is possible to manually generate metadata for a custom built tools tarball.

First, create a tarball of the relevant tools and place in a directory structured like this:

<tools_dir>/tools/releases/

Now generate relevant metadata for the tools by running the command:

juju generate-tools -d <tools_dir>

Finally, the contents of can be uploaded to a location in the Juju metadata search path. As per the Configuration section, this may be somewhere specified by the tools-metadata-url setting or the cloud's storage path settings etc.

Examples:

tools-metadata-url

upload contents of the tools dir to http://somelocation
set tools-metadata-url to http://somelocation/tools

Cloud storage

upload contents of directly to environment's cloud storage

As with image metadata, the validation command is used to ensure tools are available for Juju to use:

juju metadata validate-tools

The same comments apply. Run the validation tool without parameters to use details from the Juju environment, or override values as required on the command line. See juju help metadata validate-tools for more details.

Next step:

How do I deploy an OpenStack cloud with Juju?


Launcher vanished after disabling Unity plugin

Right click & add a folder, click on the folder to open the File Manager, go to /usr/share/applications, from there you can start CompizConfig & enable the Unity plugin.

Source (Thanks @Raja)


On your first question, yes, you may need to increase your /home directory size.

Does your hard drive has an unallocated space or is it being used by another mount point (e.g. /, /home, /swap)?

If you are doing this on a live box, please backup your files just in case.

Provided that all of the backups are taken care of, you may want to install GParted if it is not yet installed. Then you may want to use any unallocated space to expand your /home partition OR shrink your / or /swap partitions and expand your /home partition.


How to make svn look for if there is an update once a minute and if there is call some script?

The script would look something like this:

#! /bin/bash

REMOTE_REPO="svn://path/to/remote/repo"
LOCAL_REPO="/path/to/local/repo"

REMOTE_REV=`svn info $REMOTE_REPO | grep '^Revision:' | awk '{print $2}'`
LOCAL_REV=`svn info $LOCAL_REPO | grep '^Revision:' | awk '{print $2}'`

if [ $REMOTE_REV -eq $LOCAL_REV ]; then
    exit 0;
else
    # Run your commands here.
    cd $LOCAL_REPO
    svn up
fi

This script just compares the current revision number of both the local and remote svn repositories. If the differ than it runs some commands. If they are the same, it just exists.

Then you'd just have to set up a cron job to run how often you want.


You need to check whether your card supports AP mode. To do this execute the following

sudo aptitude install iw
iw list

Look for Supported interface modes:

AP should be listed


Ubuntu 12.04 update requires Lubuntu 13.04 CD/DVD

You need to edit the sources file

sudo -H gedit /etc/apt/sources.list

Comment (put a # at the beginning of) the line containing deb cdrom. Save the  file and try again.


paste selected text: switch right and middle click

You can open a terminal and paste this so the right button will behave as the middle (and the middle will behave as the right):
    xmodmap -e "pointer 1 3 2"


Ubuntu 16.04 screen tearing intel i5 ivybridge

This is answered in the post referenced below. In short the Xorg config files now live in /usr/share/X11/xorg.conf.d/{nn-name.conf} e.g. /usr/share/X11/xorg.conf.d/20-intel.conf.

Moving your config file to this location (with su/sudo) should resolve your problem after you restart Xorg. [Reboot/Save your work then sudo killall Xorg etc]. It worked for me on a Lenovo T430.

see: Intel integrated graphics screen tearing


Should I install 64-bit Ubuntu if my hardware supports it?

Points to consider:

Because address space is larger, applications do consume more RAM. It's ralatively tiny but can be a deciding factor if RAM is the deciding factor (eg in a rented server). Desktop and even laptop RAM is cheap though.
Native programmes do run faster but it's not always a tangible difference. For big things however (as you suggest you'll be doing) it can make a real difference.
Compatibility is larely irrelevant these days. Flash is available and Sun Java works (there's even a native JRE that's fairly complete). You can run most pure 32bit binaries just fine, it's just a case of installing its dependencies.
Security is not really a factor. 32bit kernels support NX bits and most of the touted features.
Neither is the total memory limit unless you have processes that require more than 4GB of RAM. The PAE kernel works.
You shoud also look to the future. I don't like to reinstall when I can help it. The future is 64 bit and its performance gains will only increase s GCC gets further extended register optimisations.

In balance, unless this was a very RAM-tight system with no scope for upgrade, I'd go 64 bit.


According to http://www.linuceum.com/Desktop/SocialMedia.php:

  Broadcast accounts are things like Twitter, Facebook or Google Buzz, which allow
  you to send updates and share things with a number of friends or
  followers over the internet. They allow you to keep up with
  whatever your friends are doing. Unlike email, broadcasting is more
  like a mail shot out to a group of people at the same time. It's not
  just text that can be shared, but files, images and video (if your
  connection's bandwidth allows)!

  Linux has a number of tools to handle broadcast messages, but the
  default for Ubuntu is Gwibber. Gwibber allows you to define all your
  social media accounts in one place, then to broadcast out across all
  of them at the same time. As an example, the next section will show
  you how to configure Gwibber with a Google Buzz account (-but the
  priciple is the same for the likes of Flickr, Facebook, Twitter, etc).


How can I debug VNC screen repainting issues?

According to RealVNC tech support (the authors of VNC Viewer client IPad software), their server software works better than Vino, with VNC Viewer and I have found that to be true.  With that in use, the viewer is much more responsive.  They have a free Linux server package for noncommercial use.

https://realvnc.com/download/vnc/latest

It appears that the Vino-VNC Viewer combo is less than ideal.  Going with the free RealVNC Server instead of Vino is an improvement.  Is there another solution on the iPad client side that works better with Vino?


the reason was a "security feature" (shitty traps) from the company I work for. If you are not connected to the VPN, it will have this strange stuff going on.
Thanks Kulfy for the help!


In order to get to "this special mode," you basically have to spam the left shift key just as the POST finishes.

Once in recovery mode, try using the "fail-safe graphics mode." If you can get to the desktop, see if there are proprietary drivers available for your GPU. (Dash > Additional Drivers)


Why don't menus in Nautilus or the desktop have shadows behind them?

This is a known issue with the RGBA window transparency support in Nautilus Elementary.
The solution is to disable it:

Edit ➜ Preferences ➜ Tweaks ➜ Uncheck 'Enable rgba transparency'

Restart Nautilus:
 killall nautilus


Why can't I compile this version of Postfix?

You should append -ldb -lnsl -lresolv to AUXLIBS.


How to get USB wireless Linksys AE6000 to work on Ubuntu

Disable Secure Boot in BIOS and run in terminal

sudo apt purge bcmwl-kernel-source
sudo add-apt-repository ppa:hanipouspilot/rtlwifi
sudo apt update
sudo apt install mt7610u-dkms

Reboot.

This will remove Broadcom drivers and install Mediatek ones.


not sure if grsec was vulnerable in the first place, but they did backport the patch for it, so you might be better off updating your kernel.

http://grsecurity.net/changelog-test.txt

commit 4f0228bf02504dc03b8230f0463677e23fdf1978
Author: Brad Spengler <spender@grsecurity.net>
Date: Mon May 5 18:12:30 2014 -0400
 Backport fix for heap overflow in the tty layer, CVE-2014-0196
 http://bugzillafiles.novell.org/attachment.cgi?id=588355


Play remote videos with local media player

You could try using vlc's built-in network stream functionality along with an open directory of video on your remote server. All you'd have to do is expose a directory of video with software like apache, nginx, etc. which allow you to expose directories of images/html/video/audio for remote downloading. Seeing as you use ask ubuntu, you probably wouldn't use Microsoft Media Server(mms), but various open alternatives like rstp(commonly used by ipcams), or my personal favorite, RTMP


MP3 Tag editing with an encrypted home directory

It looks like a permissions problem to me. On my system,

walt@squid:~(0)$ ls -ld / /home /home/walt
drwxr-xr-x 27 root root  4096 Dec 11 15:13 /
drwxr-xr-x  6 root root  4096 Feb 16  2013 /home
drwx------ 86 walt walt 24576 Dec 11 16:52 /home/walt

while yours is:

ls -ld / /home $HOME

drwxr-xr-x  25 root root  4096 Aug 22 12:23 /
drwxr-x--x   4 root root  4096 Sep 12  2012 /home
drwxr-x--x 102 matt matt 36864 Sep  1 11:47 /home/matt

I would fix this by  sudo chmod o+r /home

I'd like to point out that your "encrypted home directory" looks encrypted only when you're logged off. When you log in, it's overlaid (through mount magic) with the decrypted version. "Encrypted home directory" would be part of this problem if you want some other user to process your files while you were logged off.


python3 can participate to Ubuntu app showdown?

Yes, you can participate.
Quickly is not necessary to participate in the Ubuntu App Showdown, but make sure that required Python 3.x dependencies are present in the default repository of Ubuntu 12.04.
The rules are here. You will need to upload your app to launchpad and create a PPA.


How to completely remove a package and all related files/directories?

First of all, you missed a word, you should use

sudo apt-get --purge remove samba

or simply

sudo apt-get purge samba

By the way, the configuration file is created and removed in the Post Installation/Remove scripts of the samba-common package, a package that is installed by default because needed also for the samba client.

So the smb.conf file would only be automatically removed if you remove that package, but it is not advisable to do so without breaking the default installation.


bash script stop after execute external script(oh-my-zsh installer.sh)

It's because at the end this last line env zsh causes installer.sh run a zsh sub-shell; You can add and redirect 0>/dev/null to sh -c to fail it to run a sub-shell.

0>/dev/null sh -c "$(curl ....)"

You can check 0>/dev/null behavior when running 0>/dev/null env zsh and enz zsh after installation to see that 0>/dev/null env zsh preventing to switch to zsh shell or any other shells.

This will also cause to fail/prevent when that wants to change your default shell when asking your password in below.

if hash chsh >/dev/null 2>&1; then
      printf "${BLUE}Time to change your default shell to zsh!${NORMAL}\n"
      chsh -s $(grep /zsh$ /etc/shells | tail -1)


Update postgresql with latest security update

These updates are in the repo. 9.1.9 is the updated 9.1 release.

$ apt-cache policy postgresql-9.1
postgresql-9.1:
  Installed: (none)
  Candidate: 9.1.9-0ubuntu12.10
  Version table:
     9.1.9-0ubuntu12.10 0
        500 http://archive.ubuntu.com/ubuntu/ quantal-updates/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu/ quantal-security/main amd64 Packages

I've just noted you claim to be running PostgreSQL 9.2. If you are, getting updates for it is your responsibility. 9.2 is not a supported version in the main repos.


Installing System dynamic (Powersim studio 5) in 12.04

One option is using a virtual machine (VM), you can use oracle's VirtualBox or vmware's VMware Player to create one, then you can install back XP in the VM (hopefully you still have your licence) finally you can install Powersim Studio 5 on XP as usual.

More on virtual machines Virtual Machine.


What is the equivalent of Windows System Properties or Device Manager?

For Basic Information
Go to Settings, and under System, click on Details for basic information:

For Detailed Information (like Windows Device Manager)

Search for "system" in Software Center, and install System Profiler and Benchmark:

Then run it from the Launcher (type "system" if it isn't there already), and you will see a detailed list of hardware that you can expand further by category:

This tool also allows you to run benchmarks to compare how your system performs relative to other common computers.

Scroll down for examples of CPU and RAM information.

Other system-specific tools and console (terminal) tools
Please see Luis Alvarado's excellent exhaustive answer with screenshots  to this question, just above or below this one.

Examples of CPU and RAM information as shown in System Profiler


I had the same error.

In my case it depended to xorg.conf

I have a NvidiaCard inside my Laptop, and for another program i created the xorg.conf - file through the Button "Save to X Configuration File".

To this time everything worked fine, but after this Skype crash after the launch. So I deleted the File (xorg-conf).

Now Skype works normally, there is also the same failure - Message in the Terminal but it runs.


"fatal error, no screen found" when installing 12.04 with live USB

This might happen due to bad USB bootable flash. Recreate your flash with this, if you are a Windows user. If you are a Linux user, you can use this. Then try the installation again.


Nvidia CUDA installation issues broken cache

It's better to follow the official documentation from NVIDIA. To install CUDA on your laptop, follow this guide.


When you pair two desktopcouch instances, what happens is that the first db stores the information about the second, and syncs from it, and the second stores information about the first and syncs from that. Of course, the sync is two-way, but the point is that both will try to connect to the other. This will work as long as not both of the servers change IP address at the same time. If that happens, you'll have to ... re(-)pair them. :)

The information is stored in each couchdb management database, so have a look in your Futons and see if the information is correct.


I Just installed Ubuntu 20.04.1 and my keyboard doesn't work

BIOS
Acer Aspire V3-551G
You have BIOS 2.10.
There's a newer BIOS available, version 2.14, and can be downloaded here.
Note: Verify that I have the correct web page for your model #.
Note: Have good backups before updating the BIOS.


ubuntu application to show calendar with week numbers

The default time & calendar indicator applet has this built it - you just need to enable the option.


How do I use persistent mode on the LiveCD?

Before you reboot there are only two things that you need to remember. When the Live CD menu gets displayed hit the  key to
  enter “Other Options”. This will display the arguments that the Live
  CD passes to the kernel. At the end of this argument list just add a
  space and add the word “persistent”. This will instruct the Live CD to
  maintain and use persistence. That is all. Go for it!

To display this screen,  immediately when you see the purple screen with the symbol at the bottom (seen immediately after the boot sequence starts)  press Esc... If you got to the "try ubuntu screen" you missed the opportunity!

enter the word persistent as shown.

When you press F6 a pop-up menu will display.  Press Esc to make this menu disappear then use the keyboard arrow keys to move to the position shown in the picture.


I believe the command sudo apt-get install kubuntu-desktop would get you the results you want.


Dell XPS 13 Ubuntu 13.10 built-in display not working

Does your laptop have a "Function + ? (key with small picture of a monitor or screen)? Normally they are included and used for toggling between displays. on some models they are tied into the BIOS and their functionis independant of the OS.Take alook and let us know.


USB drive doesn't work after mounting ubuntu

Is it formatted?
Open up Gparted and see if it detects it and let us know
what information Gparted has about it.


Openstack: Allocate more memory per guest

So the problem was that the installation installs openstack in LXC, and in that container a VM is created for the compute node using libvirt, and this VM only had 4GB memory.
I was able to expand it using this guide http://earlruby.org/2014/05/increase-a-vms-available-memory-with-virsh/


How do I get the MacBook Pro isight camera working on 18.04?

For anyone who runs into this in the future, you need to run a make clean on both the facetime firmware and bdc_pci.  So...
cd facetimehd-firmware/
make clean
make
sudo make install

cd ../bcwc_pcie/
make clean
make
sudo make install

sudo depmod
sudo modprobe -r bdc_pci
sudo modprobe facetimehd
sudo vim /etc/modules

then make sure that facetimehd is still written into your modules file.
Hope this helps!


Could not apply the stored configuration for the monitor


Is there any shortcut key to align code in Geany editor?

For C, C++, C++/CLI, C#, and Java

You can achieve a similar behavior with Artistic Style 2.04.

Download the newest version, current 2.04 (do not use apt-get to install because then you will get the older version 2.03 and this version will not work for this scenario because it do not accept piped output)
Install Artistic Style -> follow the install doc (/astyle/doc/install.html) in the download (make then make install)
Add a custom command to Geany:

bash -c "astyle --indent-classes -Y"

To customize this look at the Artistic Style documentation
Select an text area and press Ctrl+1 to run the first Geany custom command

For HTML

You can use tidy, tidy can also compile your html code if you use geany.

Install tidy: sudo apt-get install tidy
Create a custom command (example):

bash -c "tidy -xml --indent auto --indent-spaces 2 --quiet yes 2> /dev/null; true"

More info:

Use HTML Tidy to just indent HTML code?
Clean up your Web pageswith HTML TIDY
tidy man page
tidy Quick Reference

For Python

Python Source Formatter/Pretty Printer (not tested)


change window left and right snap keybinding

Compiz setting manager was the right track. Look into the "grid" plugin, though; the commands put left and put right are what you are looking for.


Is there a convenient way to change the brightness at night in Ubuntu?

You have applications like RedShift, but a very simple solution would be to put two (or more) screen brightness settings under a key combination:

find out your screen name: run in a terminal xrandr, it creates an output, starting like like:

DVI-I-0 disconnected (normal left inverted right x axis y axis)
VGA-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 connected primary 1680x1050+0+0 (normal left inverted right x axis y axis)

The one that is followed by "connected" is your screen name (in this case DVI-I-1)
Now add a command and a key combination of your preference to dim the screen (System Preferences > Keyboard > Shortcuts > Custom Shortcuts). The command you need to add:

xrandr --output <your_screenname> --brightness 0.8

Add aonother command that sets the brightness to 1 again:

 xrandr --output <your_screenname> --brightness 1

If you set these commands under (e.g.) CTRL+1 and CTRL+2, you can dim / reset the screen brightness with two simple key combinations.

Option 2: if you would make it automatically

Create two simple scripts:

#!/bin/bash
xrandr --output <your_screenname> --brightness 0.8

and

#!/bin/bash
xrandr --output <your_screenname> --brightness 1

Create a directory ~/bin, paste the scripts in an empty textfile, save them in ~/binas dim_screen and reset_screen (without extension) and make them both executable.
Install Alarm Clock (from the repositories). Set one or more alarm times, but instead of running an alarm, you can make it run a (single) command (called: "Start Application"). Use as commands:

dim_screen

and

    reset_screen

(The same as the names of the scripts)


How can I enable bonded network interfaces in Ubuntu 13.04/13.10/14.04 using NetworkManager

My answer is not the correct way, and doesn't provide the combined bandwidth of proper bonding, but does provide a sort of quick'n'dirty automatic "failover" that I've found acceptable for a laptop that is sometimes hooked up to ethernet.

Set a static IP address on both the Home Ethernet and Home Wireless profiles that you use, and use identical settings on both connections, including the IP address.  When using wireless and hooking up to ethernet, once the connection is established all packets will begin routing through the ethernet adapter exclusively.  When unplugged, the packets will resume transfer through the wireless, assuming it is still actively connected.

Completely the wrong way to do it, and doesn't provide any of the advanced benefits of bonding, but it will work for most laptop users.


What would be most efficient PC configuration for professional non-linear video editing?

First of all, I can see you are interested in hardware.

Fortunatelly for you, Ubuntu is ready to edit the majority of digital video files with several software and the required codecs, which can be easily installed.

Unfortunatelly, when the thing is related to "High Definition Video" the task may be so difficult.

However, I am also waiting for the first release of LightWorks, which has already been released for MS based systems. However, you will have a few choices in ubuntu, other than LightWorks which are working pretty fine, such as: kdenlive, openshot and a few more.

But we were talking about hardware configuration. And for that I may suggest you to reach the best of two items in your bundle:

1.- The best MicroProcessor you can pay for (starting from core2duo), and...
2.- The best Graphics card (VGA, HDMI, DVI) you can get with less money. (from 512 MB will be good, 1 GB great!)

There are people which says that File Transfer Bus will be the most important thing in the architecture of a good CPU but, what would a fast FTBus be good for?, if in the case of non linear editing systems, the most important is not how the system reads the files in the hard drive, but the way the things are drawn in the screen. And I am refering to those portions of video that should be pre-rendered in order to perform a preview of the final video.

I think that the rest of the items in the bundle (motherboard and its architecture, hard disk drives and its size, and a few other accessories) can be added when needed.

However, if you find interesting, I extend you an invitation to follow my search of a good architecture (hardware and software) for the "Editing High Definition Video in Linux" thread that I am documenting in the next link:

http://ultimateeditionisrael.freeforums.org/viewtopic.php?f=89&t=618


I found out that I have to create a new file:

sudo visudo -f /etc/sudoers.d/mysudo

Putting my lines there helps. As a reason was stated the order of lines, last rule wins.

I accept this, but frankly speaking don't understand. In my sudoers is

# User alias specification

# Cmnd alias specification

# User privilege specification
root    ALL=(ALL:ALL) ALL

# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

# Allow members of group sudo to execute any command
%sudo   ALL=(ALL:ALL) ALL

# See sudoers(5) for more information on "#include" directives:

#includedir /etc/sudoers.d

As you can see includdir is even commented out and I don't know what this lines interfere with my add on. So, if someone can explain that - I would like to understand this.


Ubuntu 18.04 can't boot (emergency mode)

This happened to me too, and it took me a bit of time to realize it was due to a bad entry in my /etc/fstab... I was setting up multiple OSes on different partitions, and at some point one of the partitions' UUID changed, so when I booted a previously working OS, it failed because it didn't find the UUID defined in /etc/fstab.

To fix it I simply commented out using # the unmountable partition, then rebooted. I later was able to remount the desired partition.


Solved!

In the Configuration menu in Pavucontrol, Analog stereo input was selected.

When I chose Analog stereo duplex, the system audio out was activated and I got sound!


How can I add the Nvidia X Settings to the panel?

Disper maybe too limited for what you are asking but I think using nvidia-settings from the command line might achieve this. Use nvidia-settings --help or man for settings available.

The other program you may need is nv-control-dpy but that's not ideal as you need to build it from the source code before you can use it. It is very powerful though and I will be using it when creating a script for docking my laptop with external monitors.

To add all these commands to the gnome panel would be only possible with custom desktop entries (shortcuts) to the settings you want to switch.


Here is a filesystem loop:

/lib/recovery-mode/recovery-mode -> /lib/recovery-mode

As you can see /lib/recovery-mode/recovery-mode is symbolic link to the directory /lib/recovery-mode.

find is already searching in /lib/recovery-mode, so there is no point of following the symlink /lib/recovery-mode/recovery-mode to search in the same place /lib/recovery-mode again.

This is the reason why find is showing the filesystem looping message, you can ignore this message as find will skip this symlink and keep continuing.

The errors are showing on STDERR, not STDOUT, so you need to use grep on STDERR.

There are many ways to achieve that, the easiest would be to send both STDOUT and STDERR to grep:

sudo find .... |& grep -v 'File system loop detected'


Why does convert depend on the obsolete libg2c.so.0? How to get it to work again?

convert does not depend on libg2c. Try re-installing:

apt-get purge imagemagick
apt-get install imagemagick


How can I connect to a Microsoft Access database using PHP?

Ran into this as well. I found that the syntax for MS Access has slightly changed:

$db = new PDO("odbc:Driver={Microsoft Access Driver (*.mdb, *.accdb)};Dbq=$dbName;Uid=Admin");


14.04 - jbd2 and kworker constantly writing to disk

kworker is no big deal, jbd2 might be a debug log running (some app is set to debug), jbd2 may be MB size writes. kworker stands for "kernel worker", but again it is generally very minimal activity. I am trying to find out why jbd2 is constantly writing to all my disks every few seconds. Some say to change the "commits" in fstab to 60s, (default for ext4 is 5s). Here's an article regarding noatime vs relatime (and norelatime) for editing fstab:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Power_Management_Guide/Relatime.html


VMware on Ubuntu- Installed windows in VM - USB Issues

This is actually a Windows Guest issue, not one with Ubuntu, so this should be migrated elsewhere, in my opinion.

Use USB 2.0 instead of USB 3.0 emulation.  Only Win8+ has USB 3.0 native drivers as part of Windows, so only USB 2.0 emulation will work with Win7 and older guest OSes.

I know this because setting up the VM I use for forensics in Windows ran into this issue.  USB 2.0 emulation worked, but 3.0 failed because there's no native Windows USB 3.0 driver in Win7 and earlier (they are proprietary drivers from manufacturers for bare metal installs)