Introduction

When managing a linux/unix operating system from the command line, users are interacting with the system via shell. This article will explore some of the basic features of the bash shell prompt. Default bash command line prompt on many linux systems does not have a color and display information about user's username, hostname and current working directory. As you well see in the following sections of this document this default settings can be easily changed by exporting a bash prompt PS{n} variables. Bash prompt can be modified to suit users needs and can display time, load, number of users using the system, uptime and more.

Introduction

My restless effort to promote a Linux operating system and encourage its usage among other "PC" users made me this time to tackle a core topic of this effort and that is dual boot Linux Operating System and MS Windows XP Pro. I really do not expect windows users to switch from MS Windows to the Linux from one day to another, but I rather expect a slower and gradual transition with less headaches and without productivity losses.

There are already plenty of excellent articles in regard to this topic. However, I do still see Linux forums flooded with simple basic questions on how to dual boot these two operating systems. I see users coming from a MS Windows environment completely lost when it comes to a UNIX File System Hierarchy Standard (FHS), partitioning using EXT3 file system and navigation with simple "cd" command. It is very hard for them to let go of an idea of C: and D: drives. In recent 2 or 3 years Linux operating systems and its installation has improved in such a manner that I do not see a problem for a NON-IT person to install its own fully functional and productive version of the LINUX on his "Designed for Microsoft Windows XP" notebook.

Despite my believe I have decided to write this Linux-Windows dual boot "howto" for new Linux enthusiasts. In fact, I have had a friend who has no IT background to helping me by following my steps in this tutorial and believe it or not, he could install his own dual booting system without any problems.

Be aware that we are not going to describe all installation steps for both Linux and Windows installations in this article, only those steps which are necessary to accomplish this task.

Scenario

SSH Port Forwarding allows us to create a very simple "VPN" which lets you to secure insecure protocols such us telnet or ftp. When creating encrypted ssh connections a client needs to be connected to a ssh server on a remote host, thus creating a ssh tunnel via which an insecure information will travel. In this scenario, we are going to use ssh port forwarding to create an encrypted tunnel for telnet connection.

Enable telnet server on remote host

Let us first confirm that the telnet server is running on a remote host:

$ netstat -ant | grep 23 

Create ssh tunnel to remote host

In this example you will open port 4500 on your local host and tunnel it to the port 23 on your remote host. You do not have to do this as a root. Since we are using a port higher than 1024 a ordinary user is able to create this port forward connection. Keep in mind that a tunnel is erected only when the ssh connection is running.

# ssh -L 4500:127.0.0.1:23 linuxconfig.org 

At this point, every connection which uses port 4500 on the localhost will be redirected to remote port 23.

Telnet to remote host via ssh port forwarding

Before we attempt to telnet to a remote host via tunnel, we need to ensure that the tunnel is still running:

# netstat -ant | grep 4500 

Once we know that the tunnel is still running we can attempt to telnet on local port 4500.

# telnet localhost 4500 

This bash script tutorial assumes no previous knowledge of bash scripting.As you will soon discover in this quick comprehensive bash scripting guide, learning the bash shell scripting is very easy task. Lets begin this bash scripting tutorial with a simple "Hello World" script. Let's start with Learning the bash Shell: Unix Shell Programming

Hello World Bash Shell Script

First you need to find out where is your bash interpreter located. Enter the following into your command line:

$ which bash 

Open up you favorite text editor and a create file called hello_world.sh. Insert the following lines to a file:

NOTE:Every bash shell script in this tutorial starts with shebang:"#!" which is not read as a comment. First line is also a place where you put your interpreter which is in this case: /bin/bash.

Here is our first bash shell script example:

#!/bin/bash
# declare STRING variable
STRING="Hello World"
#print variable on a screen
echo $STRING

Navigate to a directory where your hello_world.sh is located and make the file executable:

$ chmod +x hello_world.sh 

Now you are ready to execute your first bash script:

./hello_world.sh