My First Shell Script.

My First Shell script

We are about to write a script for Hello World. After that we will have some flavors of Hello World Program. First let us create a shell script file named. HelloWorld.sh

#!/bin/sh
#This is a comment line!
echo Hello World    #This is also Comment line. 

In this the first line says Unix that the file is to be executed using /bin/sh. This is where Bourne Shell is located.

The Second line is an comment which begins with a special symbol #. This marks the line as a comment, and it is ignored completely by the shell.

The only exception is when the very first line of the file starts with #! - as ours does and this is special derivative. So, if you are using csh, ksh or any other shell it would be interpreted by the Bourne Shell (/bin/sh).

The third line runs a command named echo, with two parameters, or argument i.e. "Hello" and the second is "World".

Now let us give permission to first.sh and then run by following way

Giving Permission: chmod 777 first.sh

Running Shell Script: ./first.sh

or you may also run as: sh first.sh

sh-4.3$ chmod 777 first.sh                                                                                                                                        
sh-4.3$ sh first.sh                                                                                                                                               
Hello World! 

You may probably expect the output from terminal itself as...

sh-4.3$ echo Hello World
Hello World
sh-4.3$

Now Let us View some more examples on echo ...

#!/bin/sh
#This is a comment!

echo "Hello World"  #This is a comment, Too! 
echo "Too many                  Space"
echo Too many                       Space 
echo "Star * Between"
echo Star * Between
echo "quotes" noquotes
echo Spaces  "                  " Between
echo "Quotes"*"Star"
echo `hello` world
echo 'hello' world

You May run the above program on the following link given below. 

Program Link : https://goo.gl/qgNoMp

This is Just the beginning... If you want know more about it do comment me.. Also, we might use more powerful command than echo in future.

Regards,
Niraj Bhagchandani