This seems to be correct. If you want to be 100% sure you can check the md5sum of the file. Open a new terminal and execute:

md5sum ubuntu-18.04.1-desktop-amd64.iso

Then compare the received value with the value provided in the file MD5SUMS from the download page of Ubuntu 18.04.1 LTS (Bionic Beaver).

Download that file and then use the md5sum command with -compare option to do this check:

wget http://releases.ubuntu.com/18.04.1/MD5SUMS
md5sum -c MD5SUMS

md5sum will generate a bunch of warnings. Don't worry: the OK message will be buried somewhere within it!

Example (with suppressed error messages):

$ ls -l | grep 'ubuntu.*iso\|MD5SUMS'
-rw-rw-r-- 1 spas spas         138 юли 26 19:56 MD5SUMS
-rw-rw-r-- 1 spas spas  1953349632 ное 27 01:01 ubuntu-18.04.1-desktop-amd64.iso

$ md5sum -c MD5SUMS 2>&1 | grep 'OK'
ubuntu-18.04.1-desktop-amd64.iso: OK


Intel Turbo Boost not working properly 18.04

For full answer see: Is Turbo Boost Working?
Is Intel Turbo Boost enabled?
Using the terminal you can check if Turbo Boost feature is enabled:
$ cat /sys/devices/system/cpu/intel_pstate/no_turbo
0

This is a double negative; when "no turbo" is off (=0) then Turbo Boost is on.
To disable Turbo Boost use sudo powers and set the switch no_turbo to 1:
$ echo "1" | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
1

The returned 1 indicates turbo is now off.

I wrote cpuf to let you change the minimum and maximum frequencies to any within the allowable range:

GUI or simple Bash script to throttle the CPU?

Visit the link to copy the script or get more details.


How can I grant read-only acces to my harddrive to guest user?

Guest sessions are locked down using AppArmor, which uses a long list of special permissions to keep guest users from touching anything. These are accessed from etc/apparmor.d/lightdm-guest-session.

On my machine, that file looks like this:

# Profile for restricting lightdm guest session

#include <tunables/global>

/usr/lib/lightdm/lightdm-guest-session {
  # Most applications are confined via the main abstraction
  #include <abstractions/lightdm>

  # chromium-browser needs special confinement due to its sandboxing
  #include <abstractions/lightdm_chromium-browser>
}

Opening up that "main abstraction" (etc/apparmor.d/abstractions/lightdm) gives something more interesting:

...
/ r,
/bin/ rmix,
/bin/fusermount Px,
/bin/** rmix,
/cdrom/ rmix,
/cdrom/** rmix,
/dev/ r,
/dev/** rmw, # audio devices etc.
owner /dev/shm/** rmw,
/etc/ r,
/etc/** rmk,
...

These are all the directories which a restricted session can access, along with their permissions. If you add your hard drive to that list (with a trailing /** to include all sub-folders, and an r for read permission), all future guest sessions will have read-only access to it.


It's probably easiest to do by booting from a Live CD, i.e. boot from the install and select to test Ubuntu.

Once booted, open a terminal up and create new partitions for /usr and for /opt, although you may not have much in there. These will need to be logical partitions soyou'll need to create an extended partition (/dev/ada4) first.

You'll need several temporary mount points, so I usually create subdirectories in /mnt (e.g. /mnt/root, /mnt/usr and /mnt/opt) copy the existing contents across, then edit the existing fstab (which will be in /mnt/root/etc/fstab) to mount the new /usr and /opt.

Sequence of commands is (UNTESTED!!!) in Live CD terminal is roughly:

# fdisk /dev/sda
.... create new partitions. 4 (extended) 5 (to hold /usr) 6 (to hold /opt)
# mkdir /mnt/root
# mkdir /mnt/usr
# mkdir /mnt/opt
# mount /dev/sda1 /mnt/root
# mount /dev/sda5 /mnt/usr
# mount /dev/sda6 /mnt/opt
.... copy data
# cp -dpRxv /mnt/root/usr/* /mnt/usr
# cp -dpRxv /mnt/root/opt/* /mnt/opt
.... edit /mnt/root/etc/fstab
.... i.e. add extra lines to mount /dev/sda5 on /usr and /dev/sda6 on /opt

At this point, you you be able to boot from /dev/sda and check everything works OK, but you will notice that we haven't deleted the old contents of /usr and /opt from /dev/sda1; we've just mounted the new directories over the old ones and hence hidden their contents. This is so if it doesn't work, you can just undo the edits from fstab (delete or comment out the extra lines you added) and you'll be back where you started without losing anything.

Finally, when you've check it's OK, boot into the Live CD again, mount /dev/sda1 on /mnt and remove the old contents of /usr and /opt

# rm -Rvf /mnt/usr/* /mnt/opt/*

While I have restructured disks in the past, there is always the danger of mistyping a command and wiping out some data. In this case, since you never mount /dev/sda3 you should be OK, BUT I OFFER NO GUARANTEE AND YOU SHOULD CHECK CAREFULLY THAT YOU UNDERSTAND EACH STEP BEFORE TRYING ANYTHING!


Is my data safe during system installation?

The only measure to prevent data loss is:
Backup
It is very easy to install/upgrade Ubuntu keeping your data safe and untouched but from what we hear here it is apparently also easy to accidentally do something wrong which for so many unfortunate people led to a data loss.
Therefore whenever I plan to upgrade or install an OS I always do my regular backup before I start. I almost never needed to restore anything from that however.


ubuntu 12.10 loops with usb error 71 when booting

Check the md5sum of the iso file you used to create the install disk.  If that is OK, consider if there is something wrong with the USB header cable or the port - if there's nothing plugged in then it shouldn't be trying to connect.  Don't forget to check the USB ports on the back of the machine.

Unplug the usb header cable(s) and if that doesn't work try to disable the USB ports in BIOS.  You might also perform a BIOS reset.


E: Package 'guile-1.8-dev' has no installation candidate this is an error i got

The command apt-get download wasn't added until version 0.8.11 of apt. It was first available in Ubuntu 11.04 (which uses apt 0.8.13.2). I'm not sure what you're running as AFAICT no supported version of Ubuntu contains version 0.7.23.1 of apt. You should really have the system administrator upgrade the machine. (I know, not very helpful.)

It's not clear from your question whether or not you have access to a graphical environment. If you do, your best bet would be to grab the files from http://packages.ubuntu.com/

This is also possible from the command line as there are predictable urls. For instance:

wget http://archive.ubuntu.com/ubuntu/pool/main/a/apt/apt_0.7.25.3ubuntu9.4_i386.deb

You can find the correct version and whether the package is in main or universe by using apt-cache policy.

This is of course scriptable. Here's a quick one:

#! /bin/bash
PACKAGE=$1
URI=`apt-cache show $PACKAGE | grep "Filename:" | cut -f 2 -d " "`
wget http://archive.ubuntu.com/ubuntu/$URI


As a general rule, changing software should not make the warranty void. You will be probably able to demand warranty support. Ask more at Lenovo's official support sites or Facebook and Twitter accounts.
Also see this articles:

Softpedia

Consumerist

Lenovo Forums


Ubuntu 15.04 is not available yet and will be available in April. If you really want to test it you can download the daily build iso from here although this is highly unstable now.

After the release you can upgrade from 14.10 to 15.04 by running the following command:

sudo do-release-upgrade

I would not recommend this but if you  really want to upgrade to the latest development release:

sudo do-release-upgrade -d

EDIT :

As Ubuntu 15.04 (Vivid Vervet) has been released on 23rd April, 2015, you can upgrade from Ubuntu 14.10 to 15.04 easily now.

At first make sure the file /etc/update-manager/release-upgrades has the line:

Prompt=normal

Now run the following command:

sudo do-release-upgrade


This is the correct message since a third party website is connecting to your server and is not able to send out emails to external domains.

Ideally, as per the configuration, if you send an email to one of your own domains, then it should be delivered.

Had you been having an open relay, which means accepting emails for any domain, then it would be a big security risk and in no time your server would be blacklisted. It could also cause problems with your ISP for abuse.

Testing out the email server

I would highly recommend using services such as Mandrill.com to send out transactional emails rather than setting up your own server if you are inexperienced managing it. It can cause more harm than good.

However, based on your comment, you need to setup and test out your mail server. That is not a trivial task and requires testing at various levels. Try the following at the basic level:

a) Create a virtual domain, and a virtual user inside that domain

b) Do a telnet to the port 25 of your server and send a mail to that domain and see if it's delivered. You can check the error logs through tail -f /var/log/mail.log -f from a different console. Using telnet is easy

  telnet yourserver.com 25
  helo test.com
  mail from: <test@example.com>
  rcpt to: <youruser@yourdomain.com>
  data
  Type any content that you want, press enter, then put a period (.) and then enter to exit
  .

Now check if the email is delivered successfully through the error log. Once it's done, you'd know that incoming mails should work fine (provided A record/MX record for that domain is set correctly). Otherwise, based on the error, fix the issue.

c) Now login into the server via ssh, and use mail command to send out the email

  echo "Test Email from the new server" | mail -s "Test Subject" youruser@gmail.com

Check the spam folder of gmail as most likely, if all went well, it would have landed there. This way you would be able to check out the outgoing email.

If the java web application is residing on the same server, then you can use localhost as the email server within the application. If it is on another server, then you can enter that server's IP address under mynetworks line in postfix/main.cf, restart postfix and you can send email without authentication.

Once again, any wrong configuration can lead to misuse of the server, so be careful.


Greenpacket UH235 / MediaTek MT7118 WiMAX Modem

No good news: https://answers.launchpad.net/ubuntu/+source/gnome-nettool/+question/139831
It looks there are only drivers for 32bit linux and kernel version 2.6.28 (old! ubuntu jaunty 9.04). No new drivers on the horizon yet.


Backup my ubuntu 18.04 both (45GB) root and (1TB) home directories before resizing the root dir

My specific questions are:

What is a good way to securely do the backup? It would be great if you can give a step by step procedures for cloning. I have never done this before.

Most people use Clonezilla.

How big do I have to prepare the USB/Hard drive to save the backup file? Is it need to be as big as my root+home = 1.042TB?

For a clone, the backup disk needs to be a large as the source disk.

I also have another two hard drives mounted with my Ubuntu 18.04. Should I unmounted them before I start the backup process to avoid confusion?

Doesn't hurt.

Suppose that I was able to resize my root directory. Is there any way for me to install my backup environment back into my computer?

More difficult answer. Probably not necessary if the resizing goes without problems.

Make sure that you have a good backup of your important Ubuntu files, as this procedure can corrupt or lose data.
Keep these things in mind:

always start the entire procedure with issuing a swapoff on any mounted swap partitions, and end the entire procedure with issuing a swapon on that same swap partition

a move is done by pointing the mouse pointer at the center of a partition and dragging it left/right with the hand cursor

a resize is done by dragging the left/right side of a partition to the left/right with the directional arrow cursor

if any partition can't be moved/resized graphically, you may have to manually enter the specific required numeric data (don't do this unless I instruct you to)

you begin any move/resize by right-clicking on the partition in the lower pane of the main window, and selecting the desired action from the popup menu, then finishing that action in the new move/resize window

Do the following...
Note: if the procedure doesn't work exactly as I outline, STOP immediately and DO NOT continue.

boot to a Ubuntu Live DVD/USB, in “Try Ubuntu” mode
start gparted
resize the p3 partition by the right side and reduce the partition by 30-50G
move the p3 partition all the way right
resize the p2 partition by the right side, and extend it all the way to the right
click the Apply icon


Remove lines of code from multiple files

If you want to use the file list from find as arguments for the sed command (instead as imput, which is what your line is doing), you have to use either the xargs command:

find dir -name '*.html' | xargs -d \\n sed -i "COMMANDS"

In which case xargs takes the file list, using newline (\n) as separator between file names and starts sed with them as arguments.

Or you use the -exec option of find:

find dir -name '*.html' -exec sed -i "COMMANDS" {} +

In which case find will run the command between -exec and + while replacing {} with (a list of) file names. There is also

find dir -name '*.html' -exec sed -i "COMMANDS" {} \;

which does essentially the same, but starts a new sed for every single file name.


Unallocated space partition to Ubuntu Partition

You can move and extend system partitions with GParted from a live system:

Unmount and swap off all partitions with a key symbol in front of them (if any) through the context menu.
Grow the extended partition (sda4) to include the unallocated space in front of it.
Move and resize the logical partitions (sda5 and sda6) to your liking.
Commit the changes and wait for their completion.

Warning: There's a risk that the content of the resized file systems is corrupted in the process. For moving and growing operations it's rather low, but you should back up the important data on those partitions nonetheless. Even if the software and hardware were flawless a sudden power outage or battery failure may interrupt the process and leave the data in an inconsistent state.


Ubuntu wifi usually not working on boot, needs kernel module restart

In my experience, the hardware is highly dependent on the system that supports it. I used a Lenovo notebook sometimes back it was highly incompatible with Linux distros. I tried Ubuntu, Linux Mint and some other distros as well. Each had some problems - one such in Ubuntu & Mint was the WiFi module, similar to what you are experiencing. Out of frustration I sold the laptop and purchased the one that supports the OS I'm supposed to use. Here is the list of supported hardware by Ubuntu and Linux Mint, you can google for the rest.

Ubuntu certified - https://certification.ubuntu.com
Linux Mint supported hardware - https://community.linuxmint.com/hardware

That's an advice and try whether the tidbits in this answer help you resolve the problem.


How do I install wine x86 components on Ubuntu 12.04 x64?

Use PlayOnLinux

to install the software for you pretty much automatically.

There is a way to get the 32bit components otherwise, but I have not concretely determined if my hunch is correct (what happened in my case is that I installed a 32bit application and the 32bit subdirectory in the Wine drive was created automatically).


The same driver isn't being installed during every Ubuntu 12.04 install

you should be calm. The 300 series drivers are the current stable version, the 173 is the older one. it will work with both, but ofc it's better the use the stable newer one...
I would like to know which version is installed now.


Unable to merge two partitions of Pendrive using GParted!

try under windows and if it's recognizable try to use 'diskpart' to create partition and format usb normally


Your're missing a minus sign before the -O and missed the minus argument for zip:

curl -L someURL | tar xzf - -O | zip test.zip - works on my system with

curl 7.26.0
tar (GNU tar) 1.26
Zip 3.0


home partition not mounted during system startup

The problem was with the partition itself. I used fsck -vf /dev/sda9 (sda9 was the home partition, I knew it from /etc/fstab file). This command found and fixed some errors and OS was able to start normally again. Thank everybody for help!


Edit /etc/default/grub (sudo -H gedit /etc/default/grub)...

change:

GRUB_TIMEOUT_STYLE=hidden

to:

GRUB_TIMEOUT_STYLE=menu

then save the file and quit the editor. Next run:

sudo update-grub

GRUB_TIMEOUT_STYLE

If this option is unset or set to menu, then GRUB will display the menu and then wait for the timeout set by GRUB_TIMEOUT to expire before booting the default entry. Pressing a key interrupts the timeout.

If this option is set to countdown or hidden, then, before displaying the menu, GRUB will wait for the timeout set by GRUB_TIMEOUT to expire. If ESC is pressed during that time, it will display the menu and wait for input. If a hotkey associated with a menu entry is pressed, it will boot the associated menu entry immediately. If the timeout expires before either of these happens, it will boot the default entry. In the countdown case, it will show a one-line indication of the remaining time.


Building and installing ibus-typing-booster on Ubuntu

ibus-typing-booster is now available in Ubuntu repositories in all currently supported versions of Ubuntu.
Install ibus-m17n and ibus-typing-booster with dependencies.
In Settings > Region & Languages > Manage installed languages > language support >

install/remove language> select desired languages > apply

select ibus from the dropdown menu under Keyboard Input Method System

In Region Language > Input Sources > add an input source > three vertical dots > search with keyword "other" --> select other --> add typing booster from the list
Select typing booster keyboard in input source --> settings/preferences --> add the required dictionaries and input methods


As well as I understood, you are trying to open a database section on win..net.
Moonlight instead of silverlight can be good but it may not support those databases.

You can read this Q/A for installing moonlight extension to firefox/chrome.

Chrome installation:
http://chrome.google.com


Need to prevent a package from being installed

Is there any way to "blacklist" a package from being installed even as a dependency of another?

To prevent apt from installing a package foo, add a stanza for that package to the file /etc/apt/preferences which looks like the following.

Package: foo
Pin: release *
Pin-Priority: -1

This will prevent apt from installing foo and will also prevent apt from installing anything that Depends on foo.

The next closest thing I can think of is to put a hold on foo at its current version which prevents foo from being upgraded (unless dpkg is given the --force-hold option or unless apt overrides the hold). To put a hold on package foo, do the following.

echo foo hold | sudo dpkg --set-selections

Can I overcome the fact that it is a dependency and still be able to upgrade my system?

You can install individual packages despite dependency violations using dpkg --force-depends. You won't be able to use apt to do this unless you apt-get source the package that Depends on foo and rebuild it without the dependency on foo.


How to force Update Manager to use wired connection by default

My understanding is that when you are connected to a wired and a wireless connection at the same time, your computer will choose the wired ethernet connection. To test that theory on your laptop, plug in an ethernet cable and then go to the network manager applet in the top bar. Choose connection information from the menu and it should say you are connected to wired ethernet at the appropriate speed.


alt key shortcuts in pycharm are not working on Ubuntu 16.04

The solution that worked for me is described in this Ask Ubuntu answer.

In short: if you've already got used to combinations like Alt+F7, you can disable/change default Ubuntu shortcuts which are overlapping with default shortcuts used in PyCharm.


How can I listen to my guitar in realtime via the microphone input?

give alsamixer command in terminal, move with arrow to the microphone and press M to unmute it.


You need to configure apturl in your browser:

In Firefox you need to change the setting also in Preferences->Applications
Link the apt protocol to /usr/bin/apturl there.


Chromium (chromium-browser) uses 99,99% IO disk

Try to make it happen, then post output of free -m.

Also, please post details on what make and model of hard drive you're using, and output of df -h.

For reference, here is me looking at the %memory used by the biggest processes currently running on my system:

me@banshee:~$ ps wwaux | awk '{print $4 " " $11};' | sort -rn | head -n 10
8.1 rhythmbox
7.1 /opt/google/chrome/chrome
3.7 /opt/google/chrome/chrome
3.3 /opt/google/chrome/chrome
2.6 /opt/google/chrome/chrome
2.5 /opt/google/chrome/chrome
2.3 /usr/bin/X
2.3 /opt/google/chrome/chrome
1.9 /opt/google/chrome/chrome
1.9 compiz

Can you run the same command on your system, please, and let's see what your biggest processes are?

For reference, my system has 16G of RAM, and each of those chrome processes you see is therefore eating something along the lines of 300MB-600MB of RAM.  So, yeah, they definitely do add up.

For further reference: those are my TOP memory-hungry Chrome processes; I actually have 72 current tabs open right now and they're eating about 0.9% of my RAM (about 90MB-ish) apiece on average - the actual range is from about 10MB on the low end to about 600MB on the high end.  I haven't tried to check to see how much omgubuntu eats specifically.

A bit MORE reference: I set up a clean VM and installed chromium-browser; opening 12 tabs to http://omgubuntu.co.uk/ resulted in 1.3G used / 718M free (646M used / 1.3G free -/+ buffers/cache).  So, basically, either something OTHER than Chromium is eating most of your RAM, or you have extensions installed in Chromium that aren't very memory-efficient and are significantly bloating it per process... if I had to guess, I'd say probably the latter.  What extensions are you running?


Git wasn't installed in main environment. python36 didn't have permissions and sudo git init didn't work because git wasn't installed.

Lines of code that helped:

source deactivate python36
sudo apt-get install git
git init /home/jkbielan/python/projects/leetcode-python


What's the use for all of shutdown's options?

You have asked a bunch of questions, let me address them one by one.

Halting is when you bring the machine to a minimal power state without fully powering off the machine. Powering off the machine is what happens when you choose Shut Down from the menu and well, the machine is completely turned off.

Cancelling a running shutdown is for when a shutdown command is issued for the machine to be shutdown after a certain period of time. For example, sudo shutdown -P +6 issues the command to shutdown after 6 minutes. The -c parameter can be used to cancel the shutdown command issued earlier. To shutdown a computer instantly you issue sudo shutdown -P now

Only send warnings and don't shutdown: You must remember that Linux is a multi-user operating system where many users may be logged in to the system at a given point of time. When this command is issued, it sends a message to all the users logged in that there will be a shutdown and an additional message if the system administrator adds that as well. This gives those users time to wrap up their work so that they can be prepared for the shutdown. Think of it as a warning shot to warn the users logged in to wrap up their work although the system won't undergo a shutdown procedure.


Try deleting a few files from your home folder.

In case you have separate home, and the root partition is full,

clean cached packages

sudo apt-get clean

remove old kernels and headers

dpkg -l linux-* | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e [0-9] | xargs apt-get -y purge

To delete files from terminal, use the following commands:

cd /home/duane/ #change to the home folder

ls #list the files

rm file_name


Getting Bose USB speakers to run through USB without crackling

This happens with Fedora F17 as well, and Debian and all the distributions I have tried. When pulseaudio is disabled (ALSA-only), then there are no problems with audio.

Pulseaudio is the problem. I have also observed it is related somehow to AUDIO VOLUME as well.


Install ppa-purge .

This package provides a bash shell script capable of automatically downgrading all packages in a given PPA back to the ubuntu versions.

Run this command in a terminal:
sudo ppa-purge ppa:am-monkeyd/nautilus-elementary-ppa


I can't update or remove java 10.67.2 plugin in firefox 47.0

Updating the Java Plugin within Firefox itself doesn't work in Linux, you have to downlad the latest Oracle JDK or JRE and link to the new Plugin as described below.

Close Firefox and open the Terminal:

cd .mozilla/plugins
sudo rm -rf libnpjp2.so
ln -s /path-to-jdk-or-jre-firefox-plugin/libnpjp2.so .

Replace 'path-to-jdk-or-jre-firefox-plugin' with the real path to your latest jdk or jre on your computer. Don't forget the '.' at the end of the above line!

Start Firefox and chek in 'about:plugins' or 'Tools → Add-ons'

This should work, if the path to the plugin is correct...


Unless you specifically subscribed to a static IP from your Internet Service Provider you most likely have a dynamic IP.  That means it's subject to change at anytime without you knowing it.  If you publish your site by that IP people may eventually be connecting to a different site when your IP changes.

So if you want your specific computer/server to be available publicly you would first have to get a static IP from your Internet Service Provider (ISP).

Then you will register your domain name (an easy way for someone to access an IP Address... the domain is translated via a DNS server to your IP.  This is a service provided by the place where you registered your domain name.

So now people can connect to your computer from the outside by using either the IP or your domain name.

For security and shared IP (using the same IP with multiple computers) your actually computer is separated from the Internet via a router.  You can configure your routers (called port forwarding) to send the connection from the outside to your specific computer used for your server.

While there are many type of servers, most likely you are referring to a Web Page Server.  This is port 80.  So you will configure your router to  forward connections from the outside that is trying to communicate to port 80 to your Web Server.

A list of things you might want to look at is:

Static IP from Internet service provider
Domain registration
Router for port forwarding traffic to your desired computer


Disconnect from Internet. In the top right network icon, Right Click and untick "Enable Networking". This will turn off all network devices

Make sure you make the partitions manually, with an ext4 partition with 10gb root
and 1gb swap space.

I would suggest you unplug your ethernet while installing. Also untick the "Download updates during installation" option. Install Ubuntu normally (it hardly takes 15-25min), and after it's installed, you can use sudo apt-get update && sudo apt-get upgrade to update all packages.


Linux is the kernel that Ubuntu and many other operating systems use. Operating systems that use Linux as their kernel and use it with the most common libraries and tools (for example, GNU libc) are called Linux distributions or GNU/Linux distributions.

Confusingly, while Linux is a kernel, the term Linux is also sometimes used to refer to Linux-based operating systems (i.e., "Linux distributions"), or to refer to their shared characteristics that some people consider to comprise an operating system (of which all Linux distributions, also called GNU/Linux distributions, can be considered parallel variations). The term GNU/Linux also refers to this (and is not the name of a kernel).

All the above terms are widely considered correct, though all of them are also considered wrong by a few people here and there. You can read about the naming controversies if you like. During the ordinary course or using and talking about operating systems and kernels, they usually don't get in the way too much and most of the time terms are widely understood however they are used, from context.

As you may be aware, Wine is an emulation layer that provides an infrastructure running Windows programs. Many Windows programs run well on Wine, but also plenty run poorly or not at all. Wine runs on a wider variety of platforms than "Linux" systems. It runs on GNU/Linux distributions like Ubuntu, but also on other Unix-like systems, such as FreeBSD and Mac OS X.

Ubuntu does not come with Wine installed by default, but you can install it easily. Wine is officially packaged for Ubuntu and Wine in Ubuntu is maintained officially by the Ubuntu community (it is provided through Ubuntu's official software sources). Just open the Software Center, type in Wine, and install it when given the option to do so.

Wine is provided by the wine  package. You can also install it by running:

sudo apt-get update && sudo apt-get install wine

If you want to install the latest version of wine, see these instructions and/or this question. The Wine PPA should be pretty safe but it's a good idea to read these guidelines before using it or any other PPAs.


Set a monitor resolution not available in Display Settings?

Not a clue why, however I was able to solve the issue by simply renaming the mode. This worked:
$ xrandr --newmode "1600x900_60hz"  118.25  1600 1696 1856 2112  900 903 908 934 -hsync +vsync
$ xrandr --addmode Virtual1 "1600x900_60hz"
$ xrandr --output Virtual1 --mode "1600x900_60hz"


Can I use the embedded nautilus-terminal in Ubuntu 13.10?

Try installing nautilus-python, if you haven't already.


I am afraid to install Nvidia Drivers and break stuff

Here are the steps to install nvidia driver in Ubuntu

http://dfourtheye.blogspot.in/2013/05/ubuntu-nvidia-driver-installation.html


Sorry but IPsec do not work on that way.

There is no double encryption or ...

Very, very, very short and simple explanation how IPsec work is something like

IPsec first with IKE Police communicate with far end
Negotiate about Authorization algorithm, Encryption algorithm, Perfect Forward Secrecy and IKE version
After that send key aka password

If is everything ok, the go to phase 2

IPsec police will start
Neogoitate about Encryption algorithm, Perfect Forward Secrecy, Transform Protocol

If this go well then match routes aka access list aka interesting traffic

If everything is ok, tunnel go up.

Examples of configuration from wiki

Edit /etc/ipsec-tools.conf file. This file should be of the general form:

# Configuration for 192.168.1.100
# Flush the SAD and SPD
flush;
spdflush;

# Attention: Use this keys only for testing purposes!
# Generate your own keys!

# AH SAs using 128 bit long keys
add 192.168.1.100 192.168.2.100 ah 0x200 -A hmac-md5
        0xc0291ff014dccdd03874d9e8e4cdf3e6;
add 192.168.2.100 192.168.1.100 ah 0x300 -A hmac-md5
        0x96358c90783bbfa3d7b196ceabe0536b;

# ESP SAs using 192 bit long keys (168 + 24 parity)
add 192.168.1.100 192.168.2.100 esp 0x201 -E 3des-cbc
        0x7aeaca3f87d060a12f4a4487d5a5c3355920fae69a96c831;
add 192.168.2.100 192.168.1.100 esp 0x301 -E 3des-cbc
        0xf6ddb555acfd9d77b03ea3843f2653255afe8eb5573965df;

# Security policies
spdadd 192.168.1.100 192.168.2.100 any -P out ipsec
           esp/transport//require
           ah/transport//require;

spdadd 192.168.2.100 192.168.1.100 any -P in ipsec
           esp/transport//require
           ah/transport//require;

It is important to understand this, so let me break it down:

# AH SAs using 128 bit long keys
add 192.168.1.100 192.168.2.100 ah 0x200 -A hmac-md5
        0xc0291ff014dccdd03874d9e8e4cdf3e6;
add 192.168.2.100 192.168.1.100 ah 0x300 -A hmac-md5
        0x96358c90783bbfa3d7b196ceabe0536b;

This section lists the 128 bit keys for the 192.168.2.100 and 192.168.1.100 connection. Each IP pair has 2 keys - one for each direction (in and out). Each pair of machines needs to know the this information. So, this means that, for each pair of IP's, you need to generate a new key (hence why this works for small networks, but anything major probably wants a daemon to handle this. Maybe if I feel ambitious, I'll set mine up to use it and update this with that info).

Also, note the number right after the ah for each of these keys. This number needs to be unique for each add statement. These keys are generated as follows:

dd if=/dev/random count=16 bs=1| xxd -ps

Don't forget to add the 0x in front of it.

Similarly, this section:

# ESP SAs using 192 bit long keys (168 + 24 parity)
add 192.168.1.100 192.168.2.100 esp 0x201 -E 3des-cbc
        0x7aeaca3f87d060a12f4a4487d5a5c3355920fae69a96c831;
add 192.168.2.100 192.168.1.100 esp 0x301 -E 3des-cbc
        0xf6ddb555acfd9d77b03ea3843f2653255afe8eb5573965df;

This works just like the AH keys, except that they are longer. Again, the number after esp must be unique. These keys are generated as follows:

dd if=/dev/random count=24 bs=1| xxd -ps

Again, don't forget to add the 0x in front of it.

So, these top two sections should list keys for all the IP addresses that the machine cares about. These sections do not change when moving the file amongst machines on either side of a connection. That brings us to the next section:

# Security policies
spdadd 192.168.1.100 192.168.2.100 any -P out ipsec
           esp/transport//require
           ah/transport//require;

spdadd 192.168.2.100 192.168.1.100 any -P in ipsec
           esp/transport//require
           ah/transport//require;

This sets up the policies for in and out communications. So, the above version will work for 192.168.1.100, because all outgoing communication to 192.168.2.100 and all incoming communication from 192.168.2.100 will be encrypted. To use this on the other machine (192.168.2.100), flip the in and out directives, as follows:

# Security policies
spdadd 192.168.1.100 192.168.2.100 any -P in ipsec
           esp/transport//require
           ah/transport//require;

spdadd 192.168.2.100 192.168.1.100 any -P out ipsec
           esp/transport//require
           ah/transport//require;

Make the conf file not readable to the world:

sudo chmod 750 ipsec-tools.conf

Okay, do both sides of the connection have an ipsec-tools.conf? Everyone set? Good, now it gets easy.

It will be started at boot by default on systems, so you don't have to worry about that.

Also, starting it wouldn't hurt either (make sure to do this on both sides of the connection before trying to have them talk to each other; you could also reboot):

sudo /etc/init.d/setkey start


Changing Banshee's "Recently Added" option

Banshee's "Recently Added" playlist is just a pre-defined smart playlist, so you should be able to tweak its criteria to meet your needs.

Right click on the playlist name in the sidebar on the left, and select "Edit Smart Playlist".
In the window that opens, you can change the "Date Added" to some value greater than 1 month.

I actually prefer to have the "Recently Added" list contain a fixed number of songs instead of a time limit.  To do this, you can uncheck the box next to "Match" and instead check the box next to "Limit to." Then set Banshee to limit the playlist to x number of songs (mine is set to 500) selected by Most Recently Added.


How do I create a deb package for a precompiled files?

Yes, you can create Debian Binary Package directly

All you need is

packagename/DEBIAN/control file, example:

Package: linuxstatus
Version: 1.1-1
Section: base
Priority: optional
Architecture: all
Depends: bash (>= 2.05a-11), textutils (>= 2.0-12), awk, procps (>= \
1:2.0.7-8), sed (>= 3.02-8), grep (>= 2.4.2-3), coreutils (>= 5.0-5)
Maintainer: Chr. Clemens Lee <clemens@kclee.de>
Description: Linux system information
 This script provides a broad overview of different
 system aspects.

Your files in same structure of installation in packagename folder
Run cd ..; dpkg-deb --build packagename

Reference: Debian Binary Package Building HOWTO


Accessing Ubuntu terminal of a system outside LAN, but connected to internet

You will need to set port-forwarding on the router that connects you to the internet.

for example (choose a port number yourself):
port 10022 on the router, forwarded to port 22 of your ubuntu ip.
(I would use a port > 10000 because some providers block standard ports, and 10022 reminds me it's ssh.)

Then find out your 'internet ip', with  http://whatismyip.com

From somewhere else on the internet, then you can putty or ssh to that 'internet ip' on port 10022. What will be forwarded by your router to port 22 of your ubuntu ip.

So you will need to figure out how to configure that on your router. And have a good password, or not always leave that open ... for security reasons.

(Here port 22 is used to forward directly, what might not work or isn't advised to do so)


To view a manual page related to a package, open a terminal (press Ctrl+Alt+T together) and type:

man <package_name>

For example, to view grep's manual page, type:

man grep

This will open the manual page referring to the section numbers in the order:

1 2 3 4 5 6 7

If you want to open the manual page of a specific section, type:

man <section_number> <package_name>

For example, to open the manual page of the open() function in C, you should type:

man 2 open

More information:

Refer to the the manual page for man.
Search through Ubuntu Manpages at: http://manpages.ubuntu.com/.


Solved. I didn't realise that the following command is needed to force git to send the credentials and authentication method to the proxy:

git config --global http.proxyAuthMethod 'basic'

Source: https://git-scm.com/docs/git-config#git-config-httpproxyAuthMethod


How can I stop being prompted to unlock the 'default' keyring on boot?

Be warned that this will make your keyring accessible without a password. Period. You don't have to be logged in to view it

With that being said,

I think the simplest way is to set the password for the keyring to an empty password -- you will not be prompted for a password then:

Open Applications -> Accessories -> Password and Encryption Keys
Right-click on the "login" keyring
Select "Change password"
Enter your old password and leave the new password blank
Press ok, read the security warning, think about it and if you still want to get rid of this dialog, choose "use unsafe storage".

Again, as the message says: This will expose all your passwords (e.g. email passwords) that you chose to save in the default keyring to anyone using your computer or having access to your files and is therefore not recommended.

Addendum for Ubuntu 11.04:

In the default Unity session, you can start the application by clicking on the Ubuntu logo in the top left corner, then typing Password, and selecting Password and Encryption Keys from the search result.
In the classic session the path to start the application has changed to System → Preferences → Password and Encryption Keys

Addendum for Ubuntu 11.10:

In the default Unity session, you can start the application by clicking on the Ubuntu launcher (the first item) in the Unity launcher bar on the left side, then typing Password, and selecting Password and Encryption Keys from the search result.
In the classic session (from the gnome-session-fallback package) the path to start the application has again changed to Applications → Other → Password and Encryption Keys


Is there a virus scanner for scanning Windows files?

You can use clamav
If you want a GUI front end then you should install clamtk  as well
More information about antivirus can be found here in the Ubuntu help wiki.


"Your system is running in low graphics mode" error

The only way for me was this:

Ctrl+Alt+F1 and this command

sudo apt-get purge fontconfig-infinality

and a reboot.


Are snaps transportable between versions?

It's a waste of time to copy snap directories. Snaps are not merely a bunch of files; they are files that are placed, configured, and managed by snapd.
Use the snap command to properly install/uninstall.
Snaps are release-independent and constantly updated (those are key advantages of them). It doesn't matter which release of Ubuntu you are using. It doesn't matter which release you are migrating to (or reinstalling). There's only one current version of snap for your channel, and everybody get it.
Snaps are unaffected by deb-based do-release-upgrade or dist-upgrade. That means old snaps are not removed, new snaps are not added (exception: A set of packages converting from deb to snap), and existing snaps are updated only by coincidence.

If you are upgrading to a new release of Ubuntu, your snaps won't be touched. They will still be there.
If you are installing or re-installing Ubuntu, you must reinstall your Snaps. Use snap list to see which snaps you currently have installed so you know what to reinstall.
Your Snaps' data is usually stored in your /home directory, not in /snap. You generally don't need to backup anything in /snap.
An example of the exception (packages converting from deb to snap during a release-upgrade) include LXD and Chromium. Those deb packages were replaced with a tiny transitional package that merely installed and configured the snap. After the snap is installed, those debs can be safely uninstalled.


Problems uninstalling NetBeans 7.3.1 on Ubuntu 12.04

it have been worked for me.so you may try

go to terminal(ctrlaltt)
type cd /usr/local/netbeans-7.3.1
type sudo sh uninstall.sh
password:

then it will work.


spread a file into multiple .csv files per each line of inputfile read

It can be done with below awk command,

awk '{print > $0".csv"}' infile.csv

This will create multi .csv files named with numbers read from infile.csv


I have a Minecraft world file on a thumb drive and am trying to move it onto my Ubuntu computer

You need to transfer the world files off of the flash drive to ~/.minecraft/saves. ~, especially in Linux, is used to represent your home folder, where your Desktop, Documents, etc. are stored. This folder is usually /home/<username>. Since .minecraft begins with ., it is a hidden folder, and will not appear in a file manager. To get around this, you have to either use a terminal (see here), or instruct your file manager to show hidden files (see here How to show hidden files in Nautilus 3.20.3 Ubuntu 16.10?. It looks a little different in newer versions, but you did not specify what version of Ubuntu you were using.).
EDIT
For more information about .minecraft, see the wiki page here.


In Ubuntu, partitions may be automatically mounted when you first click on one in Nautilus, and unmounted by right-clicking and selecting "unmount". While it was mounted, you could create a working link, but after restarting, it isn't mounted until you click on it again; then, the link would work.

The solution is to explicitly mount the partition.  This connects it to the filesystem at some directory of your choosing.  So, there are several steps required, but none of them are very complicated, although slightly problematic because of permissions, especially when the partition is formatted as NTFS, which seems to be the case with yours.

For learning, you can use the mount command in a terminal, and the umount command to unmount.  But in the end, you will want to make a permanent entry in /etc/fstab, although there is a method to experiment there, too, using a form of the mount command to tell it to mount everything in the file, and see if you get errors.  If things are not to your liking, you would issue the umount command to unmount the new partition, edit the file, then try again.

This is probably not clear, but I'll explain later.

One problem is that I don't have any NTFS partitions, so I can't really tell you exactly what options to use to get the right permissions, which is why I tried not to post an answer, but commented instead.

Now, notice that the mount command gave you a line like this:

/dev/sda5 on /media/emily/ Gaming type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)

I don't know why there is a space before "Gaming", though.  That looks like an error, but it doesn't matter, as we will create a directory to use.

A...  First of all, you need to create an empty directory to use for mounting, because it needs to exist. So, to keep from getting too confused with the automatic mountpoint, create it under the directory /mnt, like so:

sudo mkdir /mnt/gaming
sudo chown emily:emily /mnt/gaming

I'm assuming emily is your username; if not, substitute whatever it is.

B...  Next step is to find a better identifier for the partition. You could use "/dev/sda5", but that's not the most reliable label, because it can change.  I personally use the disk label, for clarity, but most people seem to want to use the UUID, which is assigned at format time, and is always unique.  To find this ID, you would enter sudo blkid and look for the line starting with "/dev/sda5".  There should be a section with something like UUID="nnnnnnnnnnnnnnnn", some combination of numbers and digits.  You will copy that into the fstab file (highlight the big number, copy using shift-ctrl-C, then paste it into the file (later, though).

C... Next, open /etc/fstab for editing; I'll assume you will use gedit, but any basic editor is OK.  Enter gksu gedit /etc/fstab (because the file is owned by root).  Add a line to the end of the file:

UUID=nnnnnnnnnnnnnn /mnt/gaming ntfs-3g defaults,user_xattr 0 0

D... Save, but don't close the file.  Go to a terminal, and type mount -a.  This will mount everything in /etc/fstab, and hopefully will not give any errors. If you get any errors for the line you added, and don't understand the reason, then add a pound sign (#) to the beginning of the line to disable it, save, close, and post back for help.

If it works OK, try finding the directory /mnt/gaming, and see if the partition is accessible.  Try creating a link to that directory, and see if it works the way you want.

I hope this will help.  If not, perhaps someone else can do better, as I need to leave for now.

EDIT

I tried to add bullets and it messed up some formatting, which I didn't notice because I had to leave in a hurry.  So, 2 lines got unseparated into one, and the result was:

 sudo mkdir /mnt/gaming sudo chown emily:emily /mnt/gaming

I feel bad about this; what it did was to make more directories than the one - it created /mnt/gaming, sudo, chown, and emily:emily, and then tried again to create /mnt/gaming, resulting in the error message.  No real harm done except for some strange directories (owned by root because of sudo).  All of them except /mnt/gaming are in whatever directory you were in when you issued the command (maybe your home directory, /home/emily).  I will help you delete them when you're ready.  I'm really sorry about that; I didn't initially want to answer because I didn't have enough time, and perhaps it was a mistake to try.

Edit 2

When you typed /mnt/gaming, The system tried to run a file named "gaming" in the "/mnt" directory.  You need to do cd /mnt/gaming and then ls to see the files, or use Nautilus to find that directory under the filesystem root directory.

I don't know what the gedit error was, but it may not have been related to anything.  When you typed sudo mount -a, it should do nothing if it works; this is the linux way.  If there's an error, it tells you; otherwise it just quietly does what you expect.  So, assuming the partition shows up, it worked.

Note

I will keep checking back until solved


Canon mf8350cdn Printer installation in Ubuntu 16.04 LTS

Possible solution:

First, you'll need some prerequisites:

sudo apt-get -y install libglade2-0 libc6:i386 lib32z1 libxml2:i386 libjpeg62:i386 libstdc++6:i386

Next, download the correct driver from here (you're looking for the Linux version, and it should download a file called Linux_UFRII_PrinterDriver_V320_us_EN.tar.gz)

Once it's finished downloading, open your Terminal, and the cd to the directory where you downloaded it.

Time to extract the downloaded file:

gunzip -c Linux_UFRII_PrinterDriver_V320_us_EN.tar.gz | tar xvf -

Then cd into the 64bit Debian Driver folder like this

cd Linux_UFRII_PrinterDriver_V320_us_EN/64-bit_Driver/Debian/

Finally, install the drivers:

sudo dpkg -i *.deb


Yes, you can use extundelete command. (extundelete is a utility to recover deleted files from ext3/ext4 partition.)

  Note that the partition must be unmounted before you recover. In most cases, you will have to shut down your computer and boot using an Ubuntu LiveCD/LiveUSB to be able to this.

Steps to recover:

Install extundelete with:

sudo apt-get install extundelete
Usage example:

sudo extundelete --restore-directory /home/myself/Documents/deleted_folder/ /dev/sda1
The /dev/sda1 is the device name where the deleted data was.


Screen becomes white after exiting Full screen flash videos

This indicates an issue with your web browser Flash plug-in.  You must have the latest Flash Player installed to use full-screen mode and for hardware-scaled full-screen mode.

My best guess is that the things you are trying to view require the latest versions of java, and flash player. Also you can try HTML5, and see if the problem exists, or it disappears.  You could also ty other browsers, to see if the problem still exists.

Try using Firefox, but before playing a video, Type about:config in Firefox address bar, then type plugin.expose_full_path in the filter, then double-click it to make it true. Then type about:plugins in the address bar, find Shockwave Flash, make sure that that path is correct.

Path: /usr/lib/flashplugin-installer/libflashplayer.so
Version: Shockwave Flash 11.x rxx


"Type 'debo' is not known on line 1 in source list /etc/apt/sources.list.d/spotify.list"

Edit the /etc/apt/sources.list.d/spotify.list

sudo nano /etc/apt/sources.list.d/spotify.list

Make sure all lines begin with "deb" or "deb-src" or are comments (they start with "#"), there should be at least one that says "debo" which is a typing error.


How to install and use Ubuntu from a USB flash drive on Windows 8?

Use the Universal USB Installer to copy your ubuntu ISO file to your USB drive and make it bootable, and on the step 4 you set the amount of space it will use to store the changes, this way it won't revert to the default state when you boot.

(This software is recommended on the official Ubuntu guide).


How do I disable keyboard shortcut for Launcher in 14.04

This works for me in Ubuntu Studio 14.04 (XFCE):

Open Windows Manager: xfwm4-settings
Go to Keyboard tab
Scroll down to conflicting Action
Hit Clear (Backspace) button or change action to different shortcut


Try switching to a new kernel version. Enter a plain-text terminal via Ctrl + Alt + F3 at the black screen. Login, and run:

sudo apt remove linux-image-4.13.0-41-generic linux-image-extra-4.13.0-41-generic linux-headers-4.13.0-41-generic

Then run:

sudo apt install linux-image-4.16.8-generic linux-image-extra-4.16.8-generic linux-headers-4.16.8-generic

This should fix the issue.


No option to start Ubuntu OS after installtion

You can access the bios interface by typing fxx (usually f12 but depends on the manufacturer) right after powering your cpu. I have to do it when the Asus logo shows up.

Once in this interface you can either change the boot order (put windowsboot-manager in the second place) or override the boot manually. Usually your ubuntu booter (grub) has the name of the drive you installed ubuntu on. But once again if you don't know which boot-option is the right, just try them all.

I can just advise to look in the bios settings, once your in just look around.
If you need further help post a few screens.


Unable to restore ubuntu grub or reinstall ubuntu after installing windows 8.1

Thanks for your reply.

Sorry I am unable to attach the screenshot as I need at least 10 reputation to post image.

However, when I open gparted it shows that my whole disk as unallocated.

Thank you


lubuntu pcmanfm recently opened files and folder (history)

There is a way to do this is you go to view and make sure pathbar is set for buttons. Then type recent:// into this and you will see your recently used files. If you want to make this quicker you can even make a bookmark for it in pcmanfm by pressing control d .


Suricata IDS: No logs in /var/log/suricata

SOLVED:

The problem did not reside in any of the logging-configuration in the Suricata config-file. Instead, Suricata was scrutinizing the wrong interface and therefor had no data to process, and therefor no logs.

Buried in the Suricata configuration file, there is reference to certain interfaces, this was solved by rearranging it to direct Suricata's IDS functionality towards the correct interface.

I am plaguing the Internet with my own idiocy.


Some commands not executing in shell-script when using crontab

Finally, I found a solution.

The point of problem isn't permission but in a different shell environment than cron is executing in, especially run ruby file.

Since I'm use rvm for manage ruby versions, so I found example

#!/usr/bin/env bash

# load rvm ruby
source /usr/local/rvm/environments/ruby-2.1.1@projectX

bundle install
ruby /path/to/script.rb
rake do something

source : https://rvm.io/integration/cron#example-script

So, I have modified my shell-script looks like :

#!/usr/bin/env bash
sudo pkill -9 -f 'ruby /home/myuser/subscribe.rb'
sudo pkill -9 -f 'ruby /home/myuser/retry1.rb'
sudo pkill -9 -f 'ruby /home/myuser/retry2.rb'
sleep .5
source /home/mysuser/.rvm/environments/ruby-2.4.0
nohup ruby /home/myuser/subscribe.rb &
nohup ruby /home/myuser/retry1.rb &
nohup ruby /home/myuser/retry2.rb &


Cannot ssh to the remote server from my local computer Permission denied (publickey)

Welcome to stackexchange:askubuntu! You have successfully locked yourself out of your server. You need to contact the system operator, or possibly they have an administrative backend where you can boot into a rescue system and change the offending configuration. The file you were, most likely, told to edit is the ~/.ssh/authorized_keys file – where a pubkey line for your host should be placed. You could also change /etc/ssh/sshd_config and make sure there's a line
PasswordAuthentication yes

Which is now reading "no" - which forces the pubkey authentication, which is much more secure!


Start at https://certification.ubuntu.com.

There is a link on that page for manufacturers.


How do I get man2html pages to show in the browser?

I found this answer on the forums:

sudo a2enmod cgid

sudo service apache2 restart

Because man2html is a CGI script, Apache2 needs the module mod_cgid enabled to serve the contents of the page. It was split into two binaries: one the html converter and the other the CGI interface.

Source:
http://ubuntuforums.org/showthread.php?t=2199030


C-22 Ubuntu 14.10 64bit: "booting in insecure mode" message

You are using a UEFI boot, in BIOS, but have told the BIOS to not boot in a secure mode.  There were problems earlier with UEFI and Ubuntu, but I am using secure boot with Ubuntu 14.10 and not having issues at this time.

Secure boot prevents drivers from loading unless they have an acceptable digital signature.  You can try eneabling secure boot in your BIOS with 14.04, and if it does not work, just turn the secure boot back off.


I just checked on my machine, a Dell OptiPlex 7010. I have Legacy Mode enabled. And when looking in the menu there is a Secure Boot menu item that you do not have:

Maybe your firmware version doesn't support Secure Boot. See if you can find a more recent BIOS/UEFI version.

Also, here is where you disable UEFI and enable Legacy Boot:


ubuntu installation replacing of windows 7 without partitioning

when you are installing ubuntu it will ask you to install alongside windows or something else. click on something else and at the partition manager just select the drive that you want to install ubuntu on and it should just overwrite your windows 7 installation without partitioning


Create user's account in postfix's server

Your options are to either create a standard system user account for each user that you want to receive mail, or use Postfix's virtual mailboxes capabilities. You can find more about virtual mailboxes and virtual domains in the Postfix documentation here.


AMD R7 M265 Hybrid Graphic Card can't download driver

You can download the latest AMD driver for your card from here. AMD R7 M265 Driver download page

Detailed instructions for installing on Ubuntu 14.04 are given here. AMD Linux installation instructions


Open Firefox developer edition with ALT+F2

Bash aliases do not work from the Alt+F2 prompt as aliases are not expanded when the shell is not interactive (as per man bash).

If you want to run /opt/firefox/firefox by typing firefox in the Alt+F2 prompt then follow the steps below.

Create a folder named bin in your home directory. Make sure ~/bin/ is in your PATH. If not, add it.
Create a text file named firefox in the the aforementioned crated folder (i.e. in ~/bin/).
Add the following lines to the firefox file

#!/bin/bash
/opt/firefox/firefox

Save the firefox file and make it executable.

Note: now you can remove the alias you created if you wish as it would be redundant after following the steps above.


Ugly font rendering with Android Studio on Java8

IntelliJ and Android Studio have long had issues with font rendering. However a setting for this was added in Android Studio 2.0. It might help
Appearance and Behaviour > Appearance > Antialiasing


How to prepare Ubuntu 12.04 LTS to upgrade 14.04

Ubuntu supports in-place upgrades, and they're well tested.

To do an in-place upgrade from the command line all you need to do is sudo do-release-upgrade and follow the on-screen prompts.  New sources will be configured, new packages downloaded, and appropriate upgrade scripts run.  The process can take several hours, depending on the speed of your internet connection.

What you don't really want to do is just install Ubuntu 14.04 LTS over top of Ubuntu 12.04 LTS, because the appropriate upgrades won't take place.


OK, you're mixing up quite a few things here.

cpan is an installer for Perl modules from the CPAN, and it is installed by default
You don't download CPAN packages manually, but do `cpan CAM::PDF' to install from CPAN.
/usr/local/lib/pkgconfig is a very strange place to put these things, better delete that again.

But all of that is not needed, as Ubuntu ships CAM::PDF:

sudo apt-get install libcam-pdf-perl

Generally, if a Perl library is named Foo::Bar on CPAN, the Debian/Ubuntu package will be named libfoo-bar-perl. Use these packages before trying to install them with cpan from CPAN.


Ubuntu 19.10 avoid pasting carriage return in terminal

You could paste it into a "Here Document" (in man $SHELL):

cat <<"UnmatchedString"

<paste here>

UnmatchedString

2 caveats: "UnmatchedString" cannot be at the beginning of any pasted line, and "UnmatchedString" MUST be quoted to stop shell interpretation.

Or, you could read the command carefully before you paste it.


How to troubleshoot Gnome on Ubuntu 18.04

Here are a few paths you might want to take:

1) Create a new user.

Making a new user as a troubleshooting step will rule out if your problems stem from your user's configuration files.  A new user will have all default configuration files.  Creating a new user also will not affect any of the files in your current user's home directory.

Add the new user and give them a home directory:

sudo useradd -m newusername

Give the new user sudo privileges (if you need them):

sudo adduser newusername sudo

Reboot and log into the new user you've just created.

If everything works, there must be problems in the configs under the home directory of your old user.  See #2 below for troubleshooting if you want to "rescue" this user.

You will likely want to delete a user, either the old or the new.  To do this, use the command...

sudo userdel -r username

... to permanently delete a user and its home folder.  This command cannot be run from the user to be deleted.

2) Manually delete configs

You may want to inspect and delete configuration files for software related to the problems you are having.  You can find user-specific configs in the hidden dotfiles & folders under the user's home directory beginning with: /home/user/. (mind the dot . after user/)

For example, you may want to force your GTK configuration files to generate new defaults by moving them to a backup location:

sudo mv -r /home/user/.config/gtk-3.0 /home/user/.config/gtk-3.0-old/

This would give you precise control over what aspects of the desktop you are tinkering with, but you could really spend all day doing this.

3) Reinstall GNOME

If your problems are not solved by wiping your configuration files, a more thorough solution would be to completely reinstall GNOME.

You can do this two ways:

by using apt-get install --reinstall

Log into a virtual terminal with CTRL + ALT + F3

sudo apt update
sudo apt-get install --reinstall gnome-shell
sudo reboot

 purge & (re)install with apt

Log into a virtual terminal with CTRL + ALT + F3

sudo apt purge gnome-shell
sudo apt update
sudo apt install gnome-shell
sudo reboot

apt purge will also remove system-level configuration files, however it will not remove configuration files in your home folder.


Are there any lenses for empathy or pidgin?

I think that not exist, look here:
What lenses for Unity are available?

Obviously these aren't all the lenses available but I don't find anything about pidgin or empathy.


I'm on Ubuntu 14.04.3 LTS and couldn't get videos on the channel 4 website (e.g. http://www.channel4.com/news/catch-up or 4od) to work, and got the same VE_FMS_CONNECT_FAILED error message. I tried this

sudo add-apt-repository ppa:mjblenner/ppa-hal
sudo apt-get update && sudo apt-get install hal

Which worked for me. See here


How do I whitelist only Truecrypt's notification icon?

The right word is: truecrypt

(Note the capitalization)


How to calculate Network bandwidth, disk space, processing power and memory of a msg

It depends on how you plan to send, process, and store the message.

ASCII is one byte per character, or 7 bits if you're restricting it to printable characters.   So "I am working for three (3) hours" is 32 bytes.  If you wrote that to a file 1000 times, you'd have 32000 bytes.  If you compressed it, it would be much smaller; text compresses well.

Sending it over the network would depend on the protocol you're using to send it; plan on a few hundred bytes of overhead for each message.  You can use Wireshark or iptraf to get a detailed view of how much network traffic is passing through your machine.

The processing power required to send or receive 32000 bytes is negligible.  In general, your computer's network bandwidth will become a bottleneck before you the CPU, unless you're doing something complex with the input/output.


how to format a partition containing Master boot record in Linux 12.10?

Search for disk in dash, and click on it.  and follow the images below.

Make sure that the disk is unmounted to be be able to complete the tasks.

Click on the little wheels on the to right corner, and choose format disk.  That will setup the partition

Then click on the little wheels as shown below, and choose format to get the flash drive ready for use.  It creates the file system.


How do I fix my installation of ATI Catalyst Video Driver in 12.04 LTS?

Update of the solution (18 nov 2012)

because new drivers are available in ATI website.
Solution in 12.04LTS is then:

Uninstall ATI driver

$ sudo sh /usr/share/ati/fglrx-uninstall.sh --force   (if file is existing)
$ sudo apt-get remove --purge fglrx fglrx_* fglrx-amdcccle* fglrx-dev*

Install free driver

$ sudo rm /etc/X11/xorg.conf
$ sudo apt-get install --reinstall libgl1-mesa-glx:i386 libgl1-mesa-dri:i386 xserver-xorg-core
$ sudo dpkg-reconfigure xserver-xorg

Reboot

$ sudo reboot

Download ATI driver

Check what is your Graphic Card: lspci -v | grep -A 12 VGA

Download the appropriate driver for your machine here from the AMD/ATI Website .
File should be something like amd-driver-installer-12.6-legacy-x86.x86_64.run

If you are looking for old driver 12.6, today (Jan 2015) it is not available anymore in AMD website. Solution is to to search it in mirror websites.

Create a folder

$ mkdir ~/catalyst12.6/
$ cd ~/catalyst12.6/

And move your downloaded driver in it.
Unzip it if needed.

$ unzip amd-driver-installer-12.6-legacy-x86.x86_64.zip

Install ATI driver

$ sudo apt-get install build-essential cdbs dh-make dkms execstack dh-modaliases fakeroot libqtgui4
$ sudo chmod +x amd-driver-installer-12.6-legacy-x86.x86_64.run
$ sudo sh ./amd-driver-installer-12.6-legacy-x86.x86_64.run --buildpkg Ubuntu/`lsb_release -sc`
$ sudo dpkg -i fglrx*.deb
$ sudo amdconfig --initial -f

Reboot and Check if installation is successful

$ sudo reboot
$ sudo fglrxinfo
   display: :0  screen: 0
   OpenGL vendor string: Advanced Micro Devices, Inc.
   OpenGL renderer string: ATI Radeon HD 4200 Series
   OpenGL version string: 3.3.11653 Compatibility Profile Context

It is all good, as you can see, after last reboot, fglrxinfo displays my ATI Graphic card correctly.

Thanks

I found this solution thanks to Pavel and his link

Note

I applied successfuly this solution on 3 PCs on 12.04LTS :
- one with a ATI Radeon HD 3400
- one with a ATI Radeon HD 4200
- one with a ATI Radeon HD 4350

Successfully on hybrid ATi Radeon HD 5650/Intel with driver version 12.10, Precise Pangolin 12.04.02 with configuration in BIOS select 'discrete' graphic. (Acer aspire 4745G)


why is the markdown geany plugin missing from the repository?

The answer to your question is contained in package changelog:

geany-plugins (1.32+dfsg-3) unstable; urgency=medium

[67b34ed] Disable webkit-using plugins: markdown, webhelper
webkitgtk-3.0 is not to be used as it is deprecated, but the port to
webkit2gtk-4.0 isn't ready yet.

Then the Markdown plugin was re-enabled starting with version 1.37+dfsg-5 which came with upcoming 21.04.
So currently there are two Ubuntu versions with geany-plugin-markdown package - 16.04 LTS (will EOL in April 2021) and 21.04 (to be released in April 2021).

If you need to compile geany-markdown-plugin on 18.04 LTS use the patching and compiling method below:
software-properties-gtk # enable Source Code here, reload the lists

# get
sudo apt-get build-dep geany-plugins
sudo apt-get install libwebkitgtk-3.0-dev fakeroot

cd ~/Downloads
apt-get source geany-plugins
cd geany-plugins-1.32+dfsg

# patch
sed -i "s/--disable-peg-markdown/--enable-peg-markdown/" debian/rules
sed -i "s/--disable-markdown/--enable-markdown/" debian/rules

cat <<\EOF > ~/Downloads/debian-control.patch
55c55
< #        geany-plugin-markdown (>= ${source:Version}),
---
>          geany-plugin-markdown (>= ${source:Version}),
469,478c469,478
< # Package: geany-plugin-markdown
< # Enhances: geany
< # Architecture: any
< # Depends: ${geany:ABI}, geany-plugins-common (= ${binary:Version}),
< #         ${shlibs:Depends}, ${misc:Depends}
< # Description: markdown plugin for Geany
< #  This plugin provides a real-time preview of rendered Markdown in Geany.
< #  .
< #  Geany is a small and lightweight integrated development environment using the
< #  Gtk+ toolkit.
---
> Package: geany-plugin-markdown
> Enhances: geany
> Architecture: any
> Depends: ${geany:ABI}, geany-plugins-common (= ${binary:Version}),
>          ${shlibs:Depends}, ${misc:Depends}
> Description: markdown plugin for Geany
>   This plugin provides a real-time preview of rendered Markdown in Geany.
>   .
>   Geany is a small and lightweight integrated development environment using the
>   Gtk+ toolkit.
EOF
patch debian/control < ~/Downloads/debian-control.patch

# compile, build and install
cd ~/Downloads && apt-get source -b geany-plugins
sudo apt-get install ./geany-plugin-markdown_1.32+dfsg-3_amd64.deb

Then launch Geany and enable the plugin from in it using Tools → Plugin Manager and enjoy.
For Ubuntu 20.04 LTS this method may be adapted as follows:
software-properties-gtk # enable Source Code here, reload the lists

# get
sudo apt-get build-dep geany-plugins
sudo apt-get install libwebkit2gtk-4.0-dev fakeroot

cd ~/Downloads
apt-get source geany-plugins
cd geany-plugins-1.36+dfsg

# patch
sed -i "s/--disable-peg-markdown/--enable-peg-markdown/" debian/rules
sed -i "s/--disable-markdown/--enable-markdown/" debian/rules

cat <<\EOF > ~/Downloads/debian-control.patch
55c55
< #        geany-plugin-markdown (>= ${source:Version}),
---
>          geany-plugin-markdown (>= ${source:Version}),
469,478c469,478
< # Package: geany-plugin-markdown
< # Enhances: geany
< # Architecture: any
< # Depends: ${geany:ABI}, geany-plugins-common (= ${binary:Version}),
< #         ${shlibs:Depends}, ${misc:Depends}
< # Description: markdown plugin for Geany
< #  This plugin provides a real-time preview of rendered Markdown in Geany.
< #  .
< #  Geany is a small and lightweight integrated development environment using the
< #  Gtk+ toolkit.
---
> Package: geany-plugin-markdown
> Enhances: geany
> Architecture: any
> Depends: ${geany:ABI}, geany-plugins-common (= ${binary:Version}),
>          ${shlibs:Depends}, ${misc:Depends}
> Description: markdown plugin for Geany
>   This plugin provides a real-time preview of rendered Markdown in Geany.
>   .
>   Geany is a small and lightweight integrated development environment using the
>   Gtk+ toolkit.
EOF
patch debian/control < ~/Downloads/debian-control.patch

# compile, build and install
cd ~/Downloads && apt-get source -b geany-plugins
sudo apt-get install ./geany-plugin-markdown_1.36+dfsg-1_amd64.deb


How to start lxde (lxsession) as a non-root user from ubuntu chroot on android phone?

I use LXDE in an chrooted Debian loopback with tightvnc on my Nexus 9.

(tightvnc starts a new X-Server. You need a VNC-client app, like androidVNC, which is FOSS. You don't need a X-Sever-app.)

To start the vnc-server as non-root, you need to be in the inet-group of Android to open sockets.

root@chroot$ groupadd -g 3003 android_inet
root@chroot$ useradd NOROOTUSER android_inet

Login to your USER and start tightvnc.
Login with your favorite vncclient app to localhost:5901.

BTW, if you want to access the local sdcard, you also need to be in the sdcard_rw (gid=1015) and sdcard_r (gid=1028) group, the procedure is the same.

The gids may differ. To get them, type id -G (outside chroot) in a Terminal Emulator.

Be aware, that VNC does not encrypt! If your input is sensitive or you don't trust the network environment, use a ssh tunnel.


iptables sharing internet connection with restricted access

To do this properly, you'll really want to learn iptables so that you can troubleshoot any problems that may arise. Otherwise, iptables may become a 'black box' to you because you don't understand how to use it and prove to yourself that the problem isn't with iptables.  Don't be put off though, learning the basics of iptables really isn't that hard and if you're interested, there are many different tutorials howtos and cookbooks on the wonderful things you can do with iptables under your control (Google "upside down internet" for a comical example).

What you want to do comes down to 3 simple steps.

1) Append/Insert a rule to the FORWARD chain to accept TCP port 1688. If you require UDP access as well, add a similar rule but for UDP.

2) Append/Insert rules to accept TCP and UDP port 53 to the FORWARD chain.

3) Set the default policy on the FORWARD chain to DROP.

After a very basic crash course in iptables this should be fairly easy, don't be put off by the potential complexity because you won't need to know any of it for this, this is basic stuff.


How to modify environment variable in unix?

From help set:

set: Set or unset values of shell options and positional parameters.

So for the values you are entering with set are literally becoming positional parameters (arguments) to set rather than environment variables.

$ set foo=bar
$ echo "$foo" ##Prints nothing because it is not a variable

$ echo "$1"  ##Prints the first argument of the command "set foo=bar"
foo=bar

Now from help export:

export: Set export attribute for shell variables.

This is what you need to set a variable throughout the environment i.e. this value will be propagated to all child processes too.

$ export foo=bar  ##setting environment variable foo having value "bar"
$ echo "$foo"  ##printing the value of "foo" in current shell
bar
$ bash -c "echo $foo" ##printing the value of "foo" in a subshell
bar

So, in a nutshell you need to use the export builtin while setting any environment variable.


The installer on the website is a generic Linux installation and does not cater for specifc desktops. Open a terminal and
cd Desktop
sudo desktop-file-install ardourxxxxx.desktop

Replace ardourxxxxx.desktop with the actual filename, and enter your password when prompted.
This will add Ardour to the desktop so it will show up on the Applications screen.


How do I  remap command key to be the control key on a Macbook 4,1?

Try this:

cat > ~/.xmodmaprc
! Erase existing bindings
clear Control
clear Mod4
! Map key 37 (left ctrl) to Super_L (i.e. 'cmd')
keycode  37 = Super_L
! Map key 133 (left cmd) to Control_L (i.e. 'ctrl)
keycode 133 = Control_L
! And update modifier settings
add control = Control_L
add mod4    = Super_L

To end the input, press Ctrl+D.

To test you can run:

xmodmap ~/.xmodmaprc

Finally, you should add this command to startup applications.

This should get you started. If this does not quite work for you, checkout this for more info:

man xmodmap

To watch which key press corresponds to which internal keycode, run

xev

and press some keys when the little white window has the focus. The keycodes won't change (133 will always be 133, but you should see the name of 133 before as Control_L and after this procedure, after you log in again, it should be Super_L.


Can I delete /var/log files because of low root space in Ubuntu?

Can I delete those files ?

Yes, but do not. EMPTY them instead of deleting. Deleting files from /var/log/ requires the file to be unused and most log files are open. In theory deleting the file might crash the service that uses this log. Not a big issue unless you are hosting something that can not have downtime.

You can empty it with:

echo "" > logfile

Another note: please do not empty them without at least examining why these exists. Those logs will return and return and return. Fixing the issue that is being logged will keep those logs small.


Xubuntu 16.04 -> 18.04 media keys don't work, brightness keys are very laggy to enable

So the problem seemed to be that xfce4-notifyd was disabled (can see settings in xfce4-notifyd-config).

To check status one can do: systemctl --user status xfce4-notifyd

The solution being to start it: systemctl --user start xfce4-notifyd

I do not know if this enables it on startup, but that shouldn't difficult to add to dbus services.

With this enabled, the overlay progress bars return, and the ability to change brightness or volume at will has returned.


For kernel 5.3 you may need the newer / modified driver.

You could install the latest driver from this GitHub repo: https://github.com/aircrack-ng/rtl8812au.git

As per the repo, this is how you can install the driver using DKMS method:

sudo apt update
sudo apt install dkms
git clone -b v5.6.4.2 https://github.com/aircrack-ng/rtl8812au.git
cd rtl8812au
sudo ./dkms-install.sh

Your USB WiFi adapter should be working now.


Clonezilla to restore Ubuntu to partition dual boot with Windows

Ok, I solved this!

I already had Ubuntu installed, so I shrinked the drive down to given more space and created an ntfs partition. I then installed Win10 on there. Since the boot-up was replaced by Windows MBR, I then used the Ubuntu live USB to do a 'boot-repair' for the OS and install grub back. I can now chose any o/s to boot from now and  all working!

Thanks to this:

https://silentinfotech.com/blog/steps-to-install-windows-10-on-existing-ubuntu-16-04/


Daily builds provide new features, but are bleeding edge, and might not be suitable for production environment. For day-to-day mission-critical tasks or other tasks which demand certain amount of stability, the stable release 12.04.2 should be used.

You can use daily build on virtualbox / as a separate install to test the new features, or develop new features. In general, its advised not to use the daily build for regular systems.


Some times new kernel can result in some driver incompatibilities, so it is safe to roll back to older version until the matter is resolved.
You can simply chose old version of kernel(or make it default). If you are using grub 2
http://ubuntuforums.org/showthread.php?t=1195275 (refer point 7).


Deleting duplicate lines in text file.....?

Using awk

awk '!x[$0]++' infile.txt > outfile.txt

the way it works is that it keeps count of the lines in an array, and if the current count is zero, ie the first occurance, it prints the line, otherwise it continues to the next one.


Nvidia Corporation: G96 [GeForce 9500 GT]

These are options to install proprietary drivers. With this Nvidia card and if you are new to Ubuntu, I would no suggest installing any of proprietary Nvidia drivers. There is no guarantee that the system boots up normally after that. I know that nvidia-173 works well with this card, but I am not sure that even 304 will work. Now you use open source drivers. And if everything works OK, then it makes no much sense to change anything.

But if you choose to test if proprietary drivers work better, or work at all with this card, then you need to know how to revert system back. It can be done using system console with a command

sudo apt-get purge nvidia*

But for a new user it is not always easy to reach the console.

The AMD microcode updater is a driver, which loads microcode to your CPU. I think it is quite safe to enable it.


No sound from applications on Ubuntu 14.04 (OS does make sound)

I solved the same issue by removing the pulseaudio cache and restarting pulseaudio.

  rm -r ~/.config/pulse; pulseaudio -k


I changed Volumegroup name via Webmin, now I can't boot. Stuck on initramfs

You need to update initramfs

First start from a live USB-Device or DVD.

You need to install lvm:

$ sudo apt-get install lvm

Now mount it:

$ sudo mount /dev/sdX /mnt

where X is your ubuntu partition.

Change into your ubuntu system:

sudo mount -o bind /dev /mnt/dev
sudo mount -o bind /sys /mnt/sys
sudo mount -t proc /proc /mnt/proc
sudo cp /proc/mounts /mnt/etc/mtab
sudo chroot /mnt /bin/bash
sudo update-initramfs -k all -u
sudo reboot

Now it should work.


Why python script stops executing the statement of loop but the process itself is alive?

You answered your own question, you're running a thread as a daemon. Python threads are inherently non-deamon and this is best left off. Daemons do not terminate when the program is explicitly terminated, when you terminate the program you must join the Daemon thread back to its parent by calling .join().

Also Python can't use threads because of the GIL, so it is better to use the multiprocessing package and to implement Processes instead of Threads.

But you need to give us more code to truly answer your question.

thread = Thread(target=clientThread, args=(connection, client_address, history))
        try:
            print('Starting Thread for: ', client_address)
            thread.start()

def clientThread (connection, client_address, history):
    while True:
         data = connection.recv(512).decode('utf8')
         dataParser(connection, client_address,history, data)


Ubuntu 14.04 - HDMI connection causes horizontal split

Managed to get it working.

I plugged the HDMI cable in (caused screen split) then took it out and closed the lid. When I opened the laptop and logged back in it allowed me to connect the second monitor.


libc6:armhf issue when running dist-upgrade

I finally figured it out... the solution was to make a directory by typing

mkdir /var/cache/debconf

Many thanks to the one who posted this who also answered the question himself.

Hope this helps anybody.


From the comments...

As the user starts more apps, the system freezes. They only have 4G RAM and no swap.

Recommend creating a 8G swap partition, mkswap, lsblk, edit /etc/fstab, swapon -a, to make a working swap. If you need specific instructions, please ask.

example /etc/fstab entry:

# swap was on /dev/sda8 during installation
UUID=071f8b0e-8e16-4f4d-90ff-a4ae9cc56e2b   none   swap   sw   0   0


Run multiple Teamviewer instances at the same time

Teamviewer won't do that. What you need is something like NoMachine, such as the Workstation or Terminal Server. I.e you want to create multiple Linux instances on one machine and each user connects to their own instance without interfering with the others running there


Ubuntu file manager is not showing proper icons

The configuration for the thumbnailers for your file manager are in

/usr/share/thumbnailers

and the binaries are in

/usr/bin

e.g:

cat evince.thumbnailer

[Thumbnailer Entry]
TryExec=evince-thumbnailer
Exec=evince-thumbnailer -s %s %u %o
MimeType=application/pdf;application/x-bzpdf;application/x-gzpdf;application/x-xzpdf;application/x-ext-pdf;application/postscript;application/x-bzpostscript;application/x-gzpostscript;image/x-eps;image/x-bzeps;image/x-gzeps;application/x-ext-ps;application/x-ext-eps;application/x-dvi;application/x-bzdvi;application/x-gzdvi;application/x-ext-dvi;image/vnd.djvu;application/x-ext-djv;application/x-ext-djvu;image/tiff;application/x-cbr;application/x-cbz;application/x-cb7;application/x-cbt;application/x-ext-cbr;application/x-ext-cbz;application/x-ext-cb7;application/x-ext-cbt;application/oxps;application/vnd.ms-xpsdocument

Identify the thumbnailer configuration for the mimetype

text/x-python

via

grep -r 'text/x-python' /usr/share/thumbnailers

or only the file name of the thumbnailer configuration with

grep -ro 'text/x-python' /usr/share/thumbnailers | awk -F: '{print $1}'

Disable the thumbnailer configuration via

grep -ro 'text/x-python' /usr/share/thumbnailers | awk -F: '{system("sudo chmod o-r " $1)}'

Enable via (now you need sudo)

sudo grep -ro 'text/x-python' /usr/share/thumbnailers | awk -F: '{system("sudo chmod o+r " $1)}'


Mounting Samba Shares at boot/login and using script

The best way to do this is to create an entry in your /etc/fstab. This is the file that handles automatically mounting drives. If you have no credentials set and don't care about security, you would need to add a line like this:

//fileservername/path  /media/fileshare  cifs  username=guest,iocharset=utf8,file_mode=0777,dir_mode=0777,nobootwait   0   0

Replace fileservername/path with the hostname (or IP address) of the PC that is sharing the files, and the share name. /media/fileshare is where you want to mount the share locally. This directory must already exist. When you need to re-mount this drive, say after a connection loss, etc. use the following:

sudo mount -a

That will attempt to remount any filesystems mentioned in fstab.


Is there any way to make a hotkey turn the screen off?

If I understood well your question, you could use this commmand

xset dpms force off

In your settings, go to keyboard, shortcut, click on plus, write the name you want and past the command I just wrote, click on the new short cut and use the combination or key you want to use


Why is my system unable to locate libreadline when I'm certain I've installed it?

Following the instructions at this site seemed to work for the OP.

I'm guessing this step did the trick:

Install dependencies for Ruby:

sudo apt-get update
sudo apt-get install git-core curl zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev python-software-properties libffi-dev


How to setup /etc/host in Ubuntu to have ip 192.168.X.X

It you want other devices to see your server with the 192.168.x.x address then you need to define another interface with that 192 address.  Obviously these would need to be local devices.  I fthat is what you ask, then the /etc/hosts table is not part of the solution.

All that the hosts file does is relate an IP to a host name, so from your host is you went to http://acs/ the hosts file would resoolve that name (acs) to the hosts file defined address, 127.0.1.1,  If you put www.acs.com in the resolution would be the 10.20 IP.  Having multiple lines in etc/hosts with the same hostname is not good.  BUT, the hosts file resolves names locally so you do not need DNS.  It does not resolve external names to get to your server.


Ubuntu installation inside/outside windows - which is better?

Outside of windows is better because if it is inside of windows and if windows crash on you or if you don't want windows anymore than Ubuntu will not be bootable or gone.


Why does DrRacket load much faster on Ubuntu than on W10?

Linux is more optimized than Windows! Therefor making applications load faster! Your not the only one that was curious about this! :D


I uninstalled skype, and still have an icon in my application menu called "skype"

Did you use:

sudo apt-get remove

in order to uninstall skype?

Perhaps something is not been deleted as it should be.

Try to run this instead:

sudo apt-get --purge remove <program name>

Then reboot the system. I suggest you to install BleachBit to clean your OS.

Check your Home if something is still there, press: CTRL + H to see hidden folders, and erase everything that has skype in it.


The ArtSearch plugin has been deactivated in Rhythmbox.

Maybe a little bit of confusion here...

The plugin you mentioned is actually called AlbumArtSearch and is available through the package rhythmbox-plugin-albumartsearch.

The above package is only available for Rhythmbox v2.96 to v2.98 users.  Unfortunately the author - nor anybody else has forked the project to maintain it for later v2.99 & v3.0+ users - hence it is not in the PPA in question.

Thus to the challenge ... look over at the project website and fork the project.  Fix it up and contact me through Launchpad and I'll include it within my PPA.

Back to your issue...

The conflicting message is because you were actually trying to re-enable the default Rhythmbox plugin called CoverArt Search.  This plugin is superseded by the CoverArt Search Providers plugin that you have installed instead - the same functionality and more is available through CoverArt Search Providers.

Lastly - you might like to know that part of the Album Art Search functionality was actually incorporated into my plugin CoverArt Browser - just click on the album and the covers from Google are displayed in the Covers tab.

I've got a wiki page that describes this


Problem with Windows 7 and Ubuntu 11.04?

The System Reserved partition is necessary for windows to boot. The BSOD occured because you deleted the partition ;P

When you ran the windows repair disc, the GRUB bootloader was overwritten. Assuming the System Reserved partition has been restored you should be able to set GRUB back up by following these steps:

steps taken from raheals solution to this question.

1.boot from Ubuntu live cd (same one you used to install ubuntu with). Select "Try Ubuntu".

2.In a terminal (Accessories > Terminal) run fdisk -l and see which is your linux partition say /dev/sda2

3.mount the partition to say /mnt using mount /dev/sda2 /mnt

4.now the magic command run the following from anywhere

5.grub-install --root-partition=/mnt /dev/sda you will get the message "no error reported"

6.reboot

7.enjoy!


Avoiding situation when nova.conf file overwritten by juju

The best thing todo is to wait until this Thursday (23rd October) and then upgrade to the latest release of OpenStack Charms, which support console configuration options using spice or vnc via the charm itself, rather than you having to hack stuff into you environment directly:

juju set nova-cloud-controller console-access-protocol=spice

should then just DTRT both on the controller node and the compute nodes.


fstab won't mount during boot but does during runtime

There are two problems with the line you've shown:

The noauto option tells the computer to not automatically mount the volume. This is most likely the source of your problem.
Your options are broken up into two groups; you've got uid=1000,gid=1000,noauto,x- and then gvfs-show,umask=077,fmask=177, with several spaces between those two groups. I'm not that familiar with NTFS-3g options, but I suspect it should be x-gvfs-show in the middle, not x- by itself (which would be a very strange option name) and gvfs-show. This issue could be a typo you accidentally inserted when cutting-and-pasting the line. If not, the options in the second group are likely to be ignored.


If I install Ubuntu along side Windows 8 can I designate either OS more space later?

Yes, but this would be easily done using the Ubuntu Live USB because it would not be using the Ubuntu or Windows OS partition while loaded.

From within the Ubuntu Live USB you can open Dash and run GParted. From there simply resize whichever you want to have more/less space and done. After reboot each one will refresh the amount of space for their respective partitions.

For the cases I had worked on which are similar to your question, they normally tend to be because they can't share information between both systems. In case this is also your case (You would have to confirm just in  case it is), then my suggestion is to run the Ubuntu Live USB as mentioned above, but this time, create a 3rd partition in either FAT32 or NTFS. This way, this partition can be the bridge between sharing both systems the same information.

Note that, since you are talking about Windows 8, I will assumed it was pre-installed, so for this case, the recommended version of Ubuntu should be 15.04 to avoid other problems mentioned in the Windows 8 Pre-installed answer.


Use rename:

rename 's/ empty\.empty$/.empty/' *empty.empty

You might need to install rename:

sudo apt install rename

Alternative with pure bash:

for d in *empty; do
    mv -i "$d" "${d% empty*}.empty"
done


Terminal command for getting information about the time and user of all the commands executed in all sessions of terminal

You can check commands that executed by users using sudo vim /home/USER_YOU_WANT_TO_VIEW/.bash_history

For more you can also check AUTH logs tail /var/log/auth.log | grep username

try this similar question : How to see time stamps in bash history?


Unfortunately, I don't think that's easily doable.

If your dosemu process runs as a separate user, then you can set the priority of all processes of that user to a negative value using /etc/security/limits.conf.

EDIT: silly me, you cannot create a suid shell script, that just doesn't work.

EDIT2: OK, you can configure sudo such that it does not require you to give password when someone from the sudo group runs nice or renice. In a terminal window, enter

sudo visudo

This will open a simple text editor that will edit the configuration of sudo. Add the following line at the end of the file:

%sudo   ALL = (ALL) NOPASSWD: /usr/bin/nice,/usr/bin/renice

Exit the editor. The editor will make sure that the syntax is correct (otherwise one could break the system). Now, you can run

sudo nice -n -20 sudo -u $USER /some/program

and you will not get prompted for a password. In fact, nice will start another process called sudo with the -20 priority. This new sudo process will switch back to your original user (-u $USER, otherwise you would run the /some/program as root) and starts /some/program.


DPKG stops during configuration of linux headers - can't update or reconfigure

So I had exactly the same issue and I still don't know what the issue is but I do know what caused it. Apparently this only happens when running on the nvidia card when doing the update, the simple fix therefore is to switch to the intel card. In my case my desktop wasn't working on intel so I did the following:

Switch to a different tty (CTRL+ALT+F6 for example) then I shut down my window manager:

sudo service lightdm stop

Next I made sure to switch to the intel card:

sudo nvidia-select intel

Then in order to clean up the mess of leaving apt and dpkg in a state I ran:

sudo killall apt && sudo killall dpkg

Following that I needed to run:

sudo dpkg --configure -a

When this froze I skipped the freezing step with CTRL+C which is fine but this brought me in an okay state again, running
sudo apt update && sudo apt upgrade -y allowed me to update all my packages again! If you use a laptop with an intel and nvidia card on Ubuntu and something is not working always blame the nvidia drivers first.


Is it possible to change the colour of the launcher/dash "glass"?

In Ubuntu 11.10, the color of the launcher and dash changes to match the color of the desktop wallpaper.


Recent versions of Empathy (11.10 and up IIRC) cannot be used with twitter, because the application no longer supports this feature. Since "Online Accounts" was used to manage which accounts you can connect to, using twitter with Empathy became impossible.

You should seek to find out what is causing the crash with pidgin.


How do you open a downloaded file from synaptic?

actually the packages you are downloading through the synaptic package manager will be at /var/cache/apt/archives location in your PC.Those packages will be in .DEB format.

so if you like to open the .DEB file , you can do it with

ar vx your_package.deb.


How can I monitor the wireless signal level and frequency and log it in csv format?

When running iw help you see a warning:

  Do not screenscrape this tool, we don't consider its output stable.

There are two sections below: First a solution to your problem avoiding iw and second an answer to your question. Both work with traditional awk as well as (the default) GNU Awk.

Solution to your problem

I'd use iwconfig instead of iw:

while sleep 1; do
  iwconfig wlan0 | awk -F'[ :=]+' '/Freq/{gsub("\\.","");f=$5}/Signal/{s=$7}END{print s","f}'
done >>log.csv

Output

$ iwconfig wlan0 | awk -F'[ :=]+' '/Freq/{gsub("\\.","");f=$5}/Signal/{s=$7}END{print s","f}'
-44,2412

Notes

I got confused whether you want the values separated by , or rather a tab (which would be \t), I chose , without and surrounding spaces here. If that's not what you wanted just change s","f accordingly, s is the Signal and f the Frequency value there.
I also moved the redirection, this way the file doesn't have to be opened on each run but just once.

Explanations of the awk part

-F'[ :=]+' – sets a different field delimiter, here to one or more (+) of the three characters enclosed in square brackets
/Freq/{gsub("\\.","");f=$5} – in the line(s) with “Freq”, replace every dot by nothing (because the frequency in the iwconfig output uses a dot as the thousands separator) and save the content of the fifth column in variable f
/Signal/{s=$7} – in the line(s) with “Signal”, save the content of the seventh column in variable s
END{print s","f} – after processing the input, print the variables s and f with a literal comma between them

Answer to your question

while sleep 1; do
  iw dev wlan0 link | awk '/freq/{f=$2};/signal/{s=$2}END{print s","f}'
done >>log.csv

Output

$ iw dev wlan0 link | awk '/freq/{f=$2};/signal/{s=$2}END{print s","f}'
-43,2412

Explanations of the awk part

/freq/{f=$2} – in the line(s) with freq, save the second column (space separated) in variable f
/signal/{s=$2} – in the line(s) with signal, save the second column in variable s
END{print s","f} – after processing the input, print the variables s and f with a literal comma between them


Ubuntu 13.10 : error mounting /export/video1 on boot

nevermind, this was all my fault. /export/video1 is just an entry in my /etc/fstab file which I had copied from a different setup, which had a hard drive that this one doesn't have. I commented out that entry, and that fixed the problem on next boot.


How do I get the compiz snow plugin working?

This plugin is probably not supported for Compiz 0.9.x, from the errors you have been getting.

In a nutshell, you cannot install it in 11.10, unless it is ported to Compiz 0.9.x.


automatically organizing windows on large monitor

I accomplish a similar task using the tool wmctrl

command wmctrl -l will list the current windows

command `wmctrl -r  -e 0,X,Y,W,H will move/resize the window

Example:

wmctrl -i -r `wmctrl -l | grep "A Window Title" | tail -1 | cut -f1 -d" "` -e 0,1421,300,498,320

I have my script with a bunch of lines like the one above running on startup but I guess you could have a set of scripts and assign them to various hotkeys

Edit

To make your life a little easier move a window where you want it, run the tool xwininfo in a separate terminal and click on the window you want moved with wmctrl. xwininfo will output the height, width and all coordinates of the window you clicked on.


How can I trigger something once I connect to internet?

There is absolutely no indicator that shows whether you have an internet connection or not. That is because you always connect to some kind of gateway (router, modem, ...) that sets up the connection to your ISP. So, to be sure whether you are online or not, you have to check the connection yourself by pinging or building up an HTTP connection (using curl for example) and checking the result. But be warned: a ping response doesn't mean you can have an HTTP connection. And getting an HTTP response doesn't mean you can surf the web. You always have to check the response.

You can be sure to have an internet connection if you know the expected response. For example, you can parse websites like http://www.whatismyip.de/ for an IP address using regular expressions. If your regular expression is correct and it doesn't find an IP address then you have no internet connection.

Short answer: Write a script in which you check the internet connection (like described above). On success you execute the commands you want and set a flag that you are done for today (just create file and check for existance), on failure you do nothing. Make that script a cronjob.


Need to create a backup server to backup some windows files

Create a SAMBA server on the Ubuntu PC, then get some sort of software on the clients (Batch code, etc.) to send those directories that need to be backed up to your SAMBA server every half hour.


To add a group, use the groupadd or addgroup command. See man groupadd or man addgroup for more info.

If you've added the Ubuntu user to the vboxsf group, then you have to log the user out of Ubuntu, then log back in, for it to be seen.

Then open a Files (Navigator) window and look in the left pane for sf_SharedFolder. Click on it once to see the contents.