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i have an iso of 18.04.3 desktop-amd64.iso.  how do i burn this to a dvd?  i've done it before but i forget.  i'm currently running ubuntu 16.04.
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I have Ubuntu 16.04 (Desktop Edition) with OpenVPN server and BIND9 installed. I used a script when I installed OpenVPN. My OpenVPN client is a W10 netbook with 4G USB modem.
When I choose to use Google DNS during OpenVPN installation then I can surf the Internet via OpenVPN just fine (on my OpenVPN client W10 machine). But if I choose to use a current DNS settings (ie. my own BIND9 server), then I can connect from client to server, but DNS doesn't work. I know that I must edit config file of OpenVPN server server.conf AND to also edit client.ovpn client's OpenVPN file too. And I don't know exactly whether my DNS server (BIND9) is properly configured to play this kind of role.
When I go to W10's CMD and do ipconfig /all I do see DNS server with a correct IP of my BIND9 (it's a public IP of my Ubuntu machine, actually). Nevertheless, DNS doesn't work on a client machine and I couldn't find a complete step-by-step manual how to enable this scheme.

Having a somewhat surprising issue - our mail flow on our Zimbra server is down (both inbound and outbound) yet the server seems healthy and no error seems reported.

1. Server is up (8.8.10_GA_3786) on Ubuntu 16
2. Admin health status page shows every service up & running (green)
3. Webmail access is ok
4. IMAP access is ok

However, no mail is flowing in or out.

Trying to send triggers the following errors:


19:03:25 Ready to run action (retry count: 0)
19:03:25 Clearing connection to zimbrams.domain.com
19:03:25 Trying to connect to zimbrams.domain.com on port 465 (CFNetwork) with STARTTLS (required)
19:03:25 Resolved hostname (zimbrams.domain.com).
19:03:25 Error: Connection error (Connection refused).
19:03:25 Error code: 2
19:03:25 Failed action (0). Reset observed read/write timeouts: 8/8

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MBP13:~ alex$ telnet zimbra.domain.com 25
Trying *.*.187.68...
telnet: connect to address *.*.187.68: Connection refused
telnet: Unable to connect to remote host
MBP13:~ alex$ 

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(ie the connexion is actively refused)


method:	[unknown]
msg:	try again: Unable to connect to the MTA
code:	mail.TRY_AGAIN
detail:	soap:Receiver
trace:	qtp66233253-2518:1568314842997:7a36c58c222c3898
Body: {
  SendMsgRequest: {
    _jsns: "urn:zimbraMail",
    m: {
      e: [
        // [0]:
          a: "someone@gmail.com",
          t: "t"
        // [1]:

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I have a digital scale connected via USB to my Ubuntu laptop and I would like to read the measurements from it.
The serial protocol is very simple (9600,8N1, ttyUSB0) and I'm able to correctly read the measurements by using putty (VT100+) from terminal.

The scale needs to receive the command

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in order to send the measurement.
Each measurement has this format:
01ST,GS,   2.5,kg<CR><LF>

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if, for example, I'm measuring a 2.5Kg load.

Now, I'm trying to send the READ command from a C application, but I'm not able to get any answer.

#include <errno.h>
#include <fcntl.h> 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

int set_interface_attribs(int fd, int speed)
    struct termios tty;

    if (tcgetattr(fd, &tty) < 0) {
        printf("Error from tcgetattr: %s\n", strerror(errno));
        return -1;

    cfsetospeed(&tty, (speed_t)speed);
    cfsetispeed(&tty, (speed_t)speed);

    tty.c_cflag |= (CLOCAL | CREAD);    /* ignore modem controls */
    tty.c_cflag &= ~CSIZE;
    tty.c_cflag |= CS8;         /* 8-bit characters */
    tty.c_cflag &= ~PARENB;     /* no parity bit */
    tty.c_cflag &= ~CSTOPB;     /* only need 1 stop bit */
    tty.c_cflag &= ~CRTSCTS;    /* no hardware flowcontrol */

    /* setup for non-canonical mode */
    tty.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON);
    tty.c_lflag &= ~(ECHO | ECHONL | ICANON |

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I have an electronics board which has 16 relays and it works over TCP/IP.
The IP address of the board is and the port is 3000.
I would like to control it with C/C++ under Ubuntu.

There is a list of HEX commands that it is possible to use in order to remotely switch ON and OFF each relay on the board.
This is the list:
"580112000000016C",  // switch on the relay 1

"580111000000016B",  // switch off the relay 1
"580112000000026D", // switch on the relay 2
"580111000000026C", // switch off the relay 2
"580112000000036E", // so on..

I'm correctly able to switch on and off each relay by sending command line commands under Ubuntu:

echo '580112000000016C' | xxd -r -p | nc 3000

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The above code correctly turns on the relay.

I would like to do the same with C/C++ code since I want to control the …
Hello expert,
We are not able to run any command in our Ubuntu 18 LTS and we are getting the following error "cannot create temp file for here-document: No space left on device". So, how can I free up space if the root account is itself looked.
i have a nas which is mounted in ubuntu 16.
nas is restarted and ubuntu missing this mount.
Now i can't mount it because the old one is running i can't find the process via ps -ef | grep nfs
and i do not like to reboot server because of that.how to find process it's no possible to make ls -l /mnt/archive because it old one running
i can without any problem mount it under fx. /test but i need to stop the old one.
I've written some simple Python scripts and now I would like to write a Python script that can be installed and run as a service.

I know how to take a Python program and run it as a service but how would I write a Python program that can be installed?

My operating system is Ubuntu 18.04.
I'm developing a WxWidgets application under Ubuntu and I'm using CodeBlocks as IDE.

I need to:

  • read the data stored in a magnetic card band
  • check if they are OK
  • parse the string in order to get the code, the name and the surname

I'm using a USB magnetic card reader and I set a TextCtrl as "focused" so it immediately gets the data from the reader automatically.

The format of the string is like this:

%URSMCC84R04E815LURSO  MARCO_ò8038001605011036724_

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The control characters are always the same and I need to read everything between % and _.
I need to obtain three strings:
  • the first one containing the first 16 chars
  • the second contains the surname which goes from the 17th till the first space
  • the third string contains the name and goes from the first char after the space till the _

What is the best way to do this in Wxwidgets?
Moreover, since the reader emulates a keyboard, the output string is read a char at a time, so how can I design the parsing code?

This is the code I'm using to read the string.

void ProjectFrame::OntesseraText(wxCommandEvent& event)
    wxString stringa_tessera = tessera->GetValue(); // I read the string coming from the USB reader
    TextCtrl2->ChangeValue( stringa_tessera ); // I load the string in the second TextCtrl just for test

void ProjectFrame::OnTextCtrl2Text(wxCommandEvent& event)
// TextCtrl used to display the parsed string

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I see that there is a class wxStringTokenizer, should I use it?
I'm sorry but I'm just a beginner :(

Thank you!
my printer is a brother hl-l2340dw.  i am using ubuntu as my OS.  is there something i should do to get this printer to work?  i am hoping to get around switching to Windows.  i don't like their updates very much.  where it tells you to not shut you're computer down.
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How do I disable chef-client on a node?  7 days then autoenable is preferred.
Is gawk package installed in my linux laptop?  My linux distribution is Ubuntu 18.04 LTS

@system76-pc:~$ awk --version
awk: not an option: --version

@system76-pc:~$ which awk

@system76-pc:~$ apt-show-versions awk

Command 'apt-show-versions' not found, but can be installed with:

sudo apt install apt-show-versions
i have a very little script which is running when i use   $ ./check_dock
docker -com.... ok cpuuerc 0.xx%
 when i used in $ ./check_nrp -H "ip/localhost/" -c check_dock
return:  NRPE: Unable to read output
all other command i defined in nrpe is running.
What i missing here?

my check_dock scripts is:
#!/bin/bash -el
# Author: Bahman Sharzad
# Mail: bshmsn.sharzad@process-factory.dk

alias direc="cd /usr/local/nagios/libexec"
# . check docker container
statu=$((sudo /usr/local/nagios/libexec/check_docker -n $1 -c 80,90) | awk '{print $2}')
#echo $statu
all=$(sudo /usr/local/nagios/libexec/check_docker -n $1 -c 80,90)
#echo $all
if [ $statu = 'WARN' ]; then
        echo $all
elif [ $statu = 'CRIT' ]; then
        echo $all
elif [ $statu = 'OK' ]; then
        echo $all

and command in nrpe is
command[check_dock]=/usr/local/nagios/libexec/check_dock docker-compose_mongodb_1
i run command :  $ sudo ./check_nrpe -H -c check_dock
NRPE: Unable to read output
I remotely connect to Linux VM from windows PC puTTy terminal or remote desktop connection.  The version is Ubuntu 18.04.2 LTS.  It is 64-bit.

How to find out if this Linux distribution has xz-utils package ?
I connect to remote Linux VM from windows PC puTTy terminal or remote desktop connection.

Linux distribution version is:  Ubuntu 18.04.2 LTS
Does this distribution contain "build-essential" package?

What tools does "build-essential" package contain?

Does "build-essential" package include g++, gcc, make?  What other tools does it include?
I connect to remote Linux VM from my windows PC puTTy terminal or from remote desktop.

The Linux VM distribution is Ubuntu 18.04.2 LTS.  It is 64-bit.

How to find out if gcc-multilib is installed in my Linux VM?
i install nextcloud (16.03) on ubuntu. i try to setup mail function as:
send mode :smtp
 encryption :STARTTLS
serveradress: smtp.gmail.com port:587
(attach file)
i have error: A problem occurred while sending the email. Please revise your settings. (Error: Expected response code 250 but got code "530", with message "530-5.5.1 Authentication Required. Learn more at
 530 5.5.1 https://support.google.com/mail/?p=WantAuthError m11sm3234263lfk.56 - gsmtp

Any idea?
i set less security app on google account
I use "Remote Desktop Connection" from my windows PC to connect to remote Linux Virtual Machine running Ubuntu 18.04.2 LTS.
I open terminal window and type following command to clone git repository:

git clone git://git.yoctoproject.org/poky_local_copy

The response is as follows:
git connection failed
I open Mozilla Firefox Web Browser, enter git.yoctoproject.org and connect.  Why Web Browser connects to this site but from terminal cannot connect to this site?
i have a ubuntu lxd container (on ubuntu 18.04).
i add a domain group in visudo. and run lxc set security.priviliged true on my lxd docker.
i try to update ubuntu 16 as domain user in sudores group:
return error : sudo apt update
sudo: unable to resolve host “my-host”
sudo: no tty present and no askpass program specified.
Hi Experts,

I get the following error when I convert tiff to jpeg with wand (python library) of imagemagick on linux ubuntu machine

wand.exceptions.CoderError: Read error at scanline 3373; got 27894 bytes, expected 30000. `TIFFFillStrip' @ error/tiff.c/TIFFErrors/568

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When I open image with paint and convert it jpeg it is working fine.  But when I do it programatically it is throwing these errors.  Please help in resolving this issue.

Thank you

how to install lxd container in non default directories on ubuntu 18.0.3 server?
i try to join ubuntu 18.0.4 server to my samba rfd... domain via sssd
but sssd failed to start :
Failed to read keytab [default]: No such file or director
Exiting the SSSD. Could not restart critical service [domain]
sssd.service: Main process exited, code=exited, status=1/FAILURE
sssd.service: Failed with result 'exit-code'.
Failed to start System Security Services Daemon.

i don't forgot to unmounted my nfs connection before i remove disk and i have a directory archive like this
 d????????? ? ? ? ?            ? archive
i can't remove directory i can't change permission (chmod or chown)
i ca't find a process to kill.
how to resolve this issue?

My company site is currently hosted on windows IIS web server  called  bob.com (for example). I have setup a separate test site that is on a ubuntu apache server hosted on a different cloud provider.
I want to edit the virtual host configuration on my test site (apache) to be a subdomain of my production website. So on the test site it will be test.bob.com. Is it enough/correct way to change the ServerName to bob.com and the ServerAlias to test.bob.com ? The reason I want to edit the virtualhost config is in order that I can put an ssl cert on test.bob.com
Are there any security concerns/ will there be any connection issues?

Thank you.
I'm trying to add sFTP access for a few individual customers.  I do not want them to have shell access.  I found an article here that works.  However, I need my Samba users to be able to access these files, as well, so I needed to change the home directory.  As soon as I did that, the user is no longer able to log in.

I'm nearly certain this is a permissions issue, but I can't seem to figure out where the problem is.






Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things.