SSH in simple five steps

SSH (Secure SHELL) is an open source and most trusted network protocol that is used to login into remote servers for execution of commands and programs. It is also used to transfer files from one computer to another computer over the network using secure copy (SCP) Protocol.

In this article we will show you how to setup password-less login on RHEL/CentOS 7.x/6.x/5.x and Fedorausing ssh keys to connect to remote Linux servers without entering password. Using Password-less login with SSH keys will increase the trust between two Linuxservers for easy file synchronization or transfer.

Setup SSH Passwordless Login

owncloud : introduction & features

OwnCloud : ownCloud provides access to your data through a web interface or WebDAV while providing a platform to view, sync and share across devices easily—all under your control. ownCloud’s open architecture is extensible via a simple but powerful API for applications and plugins and works with any storage. Some features are given below :

NITROSHARE 0.3.0: EASILY SEND FILES TO OTHER MACHINES ON THE LOCAL NETWORK

NitroShare is a tool that can be used to easily transfer files between computers on your local network, available for Linux, Windows and Mac OS X.

NitroShare features:

• no configuration required: each device running NitroShare broadcasts its presence to other devices on the network;
• supports transferring files as well as directories;
• displays desktop notifications for completed transfers or when someone on the local network starts or quits NitroShare;
• simple, easy to use user interface.

Tails : Limitations & Warnings

Tor is about hiding your location, not about encrypting your communication.

Instead of taking a direct route from source to destination, communications using the Tor network take a random pathway through several Tor relays that cover your tracks. So no observer at any single point can tell where the data came from or where it's going.

The last relay on this circuit, called the exit node, is the one that establishes the actual connection to the destination server. As Tor does not, and by design cannot, encrypt the traffic between an exit node and the destination server, any exit node is in a position to capture any traffic passing through it.

Tails : Next gen operating system

Tails is a live system that aims to preserve your privacy and anonymity. It helps you to use the Internet anonymously and circumvent censorship almost anywhere you go and on any computer but leaving no trace unless you ask it to explicitly.

It is a complete operating system designed to be used from a DVD, USB stick, or SD card independently of the computer's original operating system. It is Free Software and based on Debian GNU/Linux.

How to set up networking between Docker containers

As you may be aware, Docker container technology has emerged as a viable lightweight alternative to full-blown virtualization. There are a growing number of use cases of Docker that the industry adopted in different contexts, for example, enabling rapid build environment, simplifying configuration of your infrastructure, isolating applications in multi-tenant environment, and so on. While you can certainly deploy an application sandbox in a standalone Docker container, many real-world use cases of Docker in production environments may involve deploying a complex multi-tier application in an ensemble of multiple containers, where each container plays a specific role (e.g., load balancer, LAMP stack, database, UI).

Way2SMS PHP integration

Way2SMS PHP Integration 

Way2Sms is free SMS provider in India as well as abroad, It is best in class service provider. We need SMS verification like OTP (One Time Password ), Notification and information for our website/applications. I also have same requirement for my web application where I need to send OTP for user authentication. I search a lot for free services but  now days, everyone busy to make money so There is no free service for SMS Gateway than I found a way to right a script in PHP which communicate with way2sms and send a message. Hope so it is also work for you.

Requirement : 

PHP 5.5 + 

support for PHP curl

valid way2sms account.

create cookie.txt and temporary.txt in same directory.

HAProxy (High Availability Proxy)

HAProxy(High Availability Proxy) is an open source load balancer which can load balance any TCP service. It is particularly suited for HTTP load balancing as it supports session persistence and layer 7 processing.

HA Proxy Setup  :

I was working with Apache Webserver from very long but when I jumped into the world of NodeJS I started loving websockets. Soon I was planning to integrate my PHP applications with NodeJS. I was happy to use both, till I was not running both the applications on default web service port 80. But when I tried to configure Apache virtual hosting for proxying my request to NodeJS server port, it was not allowing my websocket communication to happen. I tried alot of modules but didn’t got success. And after alot of googling I found something which helped me to achieve what I need. Once I configured HAProxy on my system I was able to serve both applications, PHP and NodeJS through port 80 just by virtual hosting of HAProxy.

How to Increase PhpMyAdmin Session Timeout from 1440 seconds

phpMyAdmin is one of my favorite tools and I use it all the time. But man, the 24-minute session timeout is a huge problem . A short cookie lifetime is all well and good on your production server, but what about when you’re just testing new things  away on the computer in your test envirnment?
Did a little grepping and found that you can override this setting, even though it’s not documented anywhere but in the codes (so far as I can tell). To override it, just open up config.inc.php in the root phpMyAdmin directory and add this setting (anywhere, but  mostly at end of file):
phpmyadmin config file for ubuntu Server : /etc/phpmyadmin/config.inc.php

$cfg['LoginCookieValidity'] = <your_new_timeout>;

Where <your_new_timeout> is some number larger than 1800. Personally, I chose 28800, which is 8 hours.

Define how long a login cookie is valid. Please note that php configuration option session.gc_maxlifetime might limit session validity and if the session is lost, the login cookie is also invalidated. So it is a good idea to set session.gc_maxlifetime at least to the same value of $cfg['LoginCookieValidity'].
php.ini file for ubuntu Server : /etc/php5/apache2/php.ini

Disclaimer! It should go without saying that increasing the timeout is a (comparatively minor) security risk (but a risk nonetheless). Obviously, do not do this on your production server. And as always, proceed with caution.

Setting up a SVN Server on a EC2 Instance (Ubuntu 14.04 LTS)

Setting up an SVN server on my EC2 instance (on AWS), is a major problem whenever we connect svn using key-file(key.pem for AWS).
Here’s my situation:

• I have a micro EC2 instance hosted with Amazon.
• I used a non-standard port for ssh access
• I have a pem file provided by Amazon for access through ssh
• I run Ubuntu 14.04 Server on my EC2 instance
• On the client side, I’m running Ububtu 14.04 Desktop

With that out of the way, the first thing I had to do was insure svn was installed on my server and Desktop :

sudo apt-get install -y subversion

Then, on my EC2 instance, I want to create both the directory where I’ll store repositories, and the subsequently, create the repository itself. Permissions and ownership are of the utmost importance. This worked for me:

sudo mkdir -p /srv/svn/
sudo chown ubuntu:ubuntu /srv/svn/
svnadmin create /srv/svn/{repo_name}
Mind the {rep_name} placeholder above 

vim /svnrepos/conf/svnserve.conf

In that file add these three lines:

anon-access = none
auth-access = write
password-db = passwd

Create a password file:

vi /svnrepos/conf/passwd

In that file add a line for your user:

# add users in the format : user = password
tony = mypassword

Ubuntu : Netbeans Installation

This Guide is useful for Netbeans Installation on Ubuntu. Generally we face problems during installation of Netbeans like JDK path, package not available, permissions denied etc. This guide gives  you step by step instructions to easy installation of Netbeans. Hope so it helps you a lot !

1. Update your Ubuntu 14.04 :
Ubuntu is open-source operating system which provides updates frequently for users to overcome security breaches and enhance user experience. Just type this command on your terminal : (open terminal using Ctrl+Alt+t or type terminal in ubuntu search bar )       

sudo add-apt-update

For LAMP stack use following commands :
sudo apt-get install apache2
sudo apt-get install php5
sudo apt-get install mysql-server mysql-client
sudo apt-get install phpmyadmin
 
2. Download Netbeans from official website :  
Select your os type(32/64 bit) and download from following link :
                               https://netbeans.org/downloads/

Linux Basic Tutorials Part - 8

UNIX/Linux Tutorial 

UNIX Variables

Variables are a way of passing information from the shell to programs when you run them. Programs look "in the environment" for particular variables and if they are found will use the values stored. Some are set by the system, others by you, yet others by the shell, or any program that loads another program. 

Standard UNIX variables are split into two categories, environment variables and shell variables. In broad terms, shell variables apply only to the current instance of the shell and are used to set short-term working conditions; environment variables have a farther reaching significance, and those set at login are valid for the duration of the session. By convention, environment variables have UPPER CASE and shell variables have lower case names.

Linux Basic Tutorials Part - 7

UNIX/Linux Tutorial

Other useful UNIX commands  

quota

All students are allocated a certain amount of disk space on the file system for their personal files, usually about 100Mb. If you go over your quota, you are given 7 days to remove excess files.

To check your current quota and how much of it you have used, type

% quota -v

Linux Basic Tutorials Part - 6

UNIX/Linux Tutorial 

File system security (access rights)

In your unixstuff directory, type

% ls -l (l for long listing!)

You will see that you now get lots of details about the contents of your directory, similar to the example below.

Each file (and directory) has associated access rights, which may be found by typing ls -l. Also, ls -lg gives additional information as to which group owns the file (beng95 in the following example):

-rwxrw-r-- 1 ee51ab beng95 2450 Sept29 11:52 file1

In the left-hand column is a 10 symbol string consisting of the symbols d, r, w, x, -, and, occasionally, s or S. If d is present, it will be at the left hand end of the string, and indicates a directory: otherwise - will be the starting symbol of the string. 

Linux Basic Tutorial Part - 5

UNIX/Linux Tutorial

Wildcards

The * wildcard

The character * is called a wildcard, and will match against none or more character(s) in a file (or directory) name. For example, in your unixstuff directory, type

% ls list*

This will list all files in the current directory starting with list....

Try typing

% ls *list

This will list all files in the current directory ending with ....list

Linux Basic Tutorials Part -4

UNIX/Linux Tutorial 

Redirection  

Most processes initiated by UNIX commands write to the standard output (that is, they write to the terminal screen), and many take their input from the standard input (that is, they read it from the keyboard). There is also the standard error, where processes write their error messages, by default, to the terminal screen.

We have already seen one use of the cat command to write the contents of a file to the screen.

Linux Basic Tutorials Part - 3

UNIX/Linux Commands

 Copying Files

cp (copy)

cp file1 file2 is the command which makes a copy of file1 in the current working directory and calls it file2 

What we are going to do now, is to take a file stored in an open access area of the file system, and use the cp command to copy it to your unixstuff directory.

First, cd to your test directory.

% cd ~/unixstuff

Then at the UNIX prompt, type,

% cp /vol/examples/tutorial/science.txt .

Note: Don't forget the dot . at the end. Remember, in UNIX, the dot means the current directory.

The above command means copy the file science.txt to the current directory, keeping the name the same.

(Note: The directory /vol/examples/tutorial/ is an area to which everyone in the school has read and copy access.

Linux Basic Tutorials Part - 2

After looking on Open Source and GNU . We look around basic command of the Linux/Unix.

1.1 Listing files and directories

ls (list)

When you first login, your current working directory is your home directory. Your home directory has the same name as your user-name, for example, john123, and it is where your personal files and subdirectories are saved.

To find out what is in your home directory, type

% ls

The ls command ( lowercase L and lowercase S ) lists the contents of your current working directory.

There may be no files visible in your home directory, in which case, the UNIX prompt will be returned. Alternatively, there may already be some files inserted by the System Administrator when your account was created.

ls does not, in fact, cause all the files in your home directory to be listed, but only those ones whose name does not begin with a dot (.) Files beginning with a dot (.) are known as hidden files and usually contain important program configuration information. They are hidden because you should not change them unless you are very familiar with UNIX!!!

To list all files in your home directory including those whose names begin with a dot, type

% ls -a

As you can see, ls -a lists files that are normally hidden.

ls is an example of a command which can take options: -a is an example of an option. The options change the behaviour of the command. There are online manual pages that tell you which options a particular command can take, and how each option modifies the behaviour of the command. (See later in this tutorial) 

Linux Basic Tutorials Part - 1

Welcomes you all to New and exciting world of Linux. Most used operating system by modern servers, super-computers and desktops. Now I am here to help to understand basic of Linux.

Open Source & GNU Foundation

Starting Linux before we learn some technologies and concepts behind it. Let's look about Open source and GNU Foundation.

Open source is an approach to the design, development, and distribution of software, offering practical accessibility to a software's source code. Some consider open source as one of various possible design approaches, while others consider it a critical strategic element of their operations. Before open source became widely adopted, developers and producers used a variety of phrases to describe the concept; the term open source gained popularity with the rise of the Internet, which provided access to diverse production models, communication paths, and interactive communities.

Software development costs in organizations have been touted as being approximately 15% of total costs. This indicates that the value of one over another development methodology is more of a marketing decision (which customers and pricing models) as much as it is about the design of software. The open source model of operation and decision making allows concurrent input of different agendas, approaches and priorities, and differs from the more closed, centralized models of development The principles and practices are commonly applied to the peer production development of source code for software that is made available for public collaboration. The result of this peer-based collaboration is usually released as open-source software, however, open source methods are increasingly being applied in other fields of endeavour, such as biotechnology 

The Open Source Definition is used by the Open Source Initiative to determine whether or not a software license can be considered open source.