#!/bin/bash

# Folks I wrote this to show the difference between the 
# manipulation of $arg which loads the scripts input 
# parameters in; a variable being incremented i,
# and finally using $1 and shift as a combo to
# walk through the input arguments to the script

# Here is an example of running the script with input:
#
#$ ./shift.sh one two three four 
#
#
# First let's print the scripts environmental variables:

echo $0 is the name of the script                                                                   
echo $# is the number of parameters entered by the user                                             
echo $$ is the process ID                                                                           
echo $@ is the list of parameters entered        

# and the output
#
#This is the arg value one
#This is the variable value 0
#This is the $1 value one
#This is the arg value two
#This is the variable value 1
#This is the $1 value two
#This is the arg value three
#This is the variable value 2
#This is the $1 value three
#This is the arg value four
#This is the variable value 3
#This is the $1 value four

i=0 # variable i increment using let

for arg in $@ # you don't need in $@ because by default it is that
do
   echo This is the arg value $arg
   echo This is the variable value $i
   echo This is the '$1' value $1
   let i=i+1
   shift
done