Tag: linux

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Generate EAN,UPC,ISBN barcodes in Ubuntu / Debian Linux

‘barcode‘ is a utility in Debian GNU/Linux distribution used for generating common 1-D barcode: EAN-13, EAN-8, UPC, ISBN, code93, code128 & codabar.
barcode outputs file in postscript format which can be converted to PDF with the ‘ps2pdf‘ utility

Usage:

1. Outputs isbn barcode and converts it to PDF file

$  barcode -o barcode.ps -e isbn
$  ps2pdf barcode.ps

2. Outputs EAN-13 barcode 

$ barcode -o barcode-ean.ps -e ean

If you are looking for a tool that could generate QR Code, then you can try ‘qrencode‘

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Ubuntu TV Preview & Features

Here are the preview of Ubuntu TV, a line of Ubuntu powered device designed for home consumers.

A class of Smart TV device, Ubuntu TV supports few key features:

  • Youtube Integration
  • Intelligent search
  • Cloud Storage via Ubuntu One
  • Social Networking Integration
  • Tablets / Smartphone dock option
  • Support for 3rd party application and games

Visit Ubuntu TV wiki for more information.

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Solving SSH “channel 3: open failed: administratively prohibited” error when tunnelling

A couple of days ago, I’ve encountered this error when I was trying to create a SSH tunnel from my office LAN to a remote server.

After looking for a solution, I found out that the remote SSH server must add “PermitTunnel yes” line in “/etc/ssh/sshd_config” file.

To do that, you need to:

sudo echo "PermitTunnel yes" >> /etc/ssh/sshd_config
service sshd restart

The second line is used to restart the ssh service in order to enable the changes.

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How to send Email with SMTP using Telnet in GNU/Linux

SMTP is a protocol to send email over the internet and it is documented in RFC821. Sending email using Telnet is straight-forward if you know how to do it.

telnet smtp.example.com 25
MAIL FROM: <example_from @ example.com>
RCPT TO: <example_to @ example.com>
DATA
From: [John Doe] <example_from @ example.com>
To: [Jane Doe] <example_to @ example.com>
Subject: This is a test message....

This is an example email content to demonstrate email sending using Telnet.

.

QUIT
[/pre]

Note that you need to type "." and QUIT after you've finished writing the email content. You should change the SMTP server domain and the email used in the example accordingly.
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Backup your Gmail account in Ubuntu Linux with gmvault

This is a follow-up of my previous post “What to do when your Google disabled your Gmail account?“.

Here’s how to download all emails from your GMail account with Gmvault:

Download and setting up gmvault

1. First you need to install python-pip
[bash]
sudo apt-get install python-pip
[/bash]

2. Then using ‘pip’, install gmvault
[bash]
sudo pip install gmvault
[/bash]

3. Finally you can sync and backup GMail accounts with ‘gmvault‘
[bash]
gmvault sync your_username @ gmail.com
[/bash]

4. gmvault will ask you to authenticate yourselves with GMail, and after that, the syncronization process starts. gmvault stores all the gmail backup in the ‘gmvault-db‘ directory.

p/s: Some users encounters error telling that the “All Mail folder is not visible”. You can enable All Mail folder visibility by checking the “Show in IMAP” box in Settings->Labels. Also, IMAP access should also be enabled for this to work.

p/s 2: It might not be obvious right now why you need to backup your emails when Gmail has gigabytes of storage. But according to Gmail discussions group, Google can and might disable access to all of its services, locking the users out from their emails forever.

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iotop: How to monitor processes that hogs hard disk writes

iotop is a small and handy tool to monitor processes that hogs I/O resources. iotop outputs is similar to ‘top’ except it lists the hard disk read/write activity as well as swap writes.

You can use the left and write key to sort the heading according to your preference and the R key can be used to reverse the sort. The ‘O’ key is used when you only wants it to display processes that are currently utilizing the disk I/O. While the ‘P’ key can be used to display accumulated IO disk read/write for all the processes (which can be sorted with the arrow keys).