Creating array with Bash shell

[Carnie]

Hello sir ,

I am newbie in the linux programming and need some guidence regarding creation and implementation of array in Linux.The basic things I don't know.How would I implement in a large application and whenever I required to put some different command to system through the script then How would I do.

Thanks and regards
C. Pammela

[jesse]

Creating array with Bash shell :

The array is very useful user defined data type which represent a number of variable of same data type.To create a array in Linux on bash shell wold be as follows:

array_var=(Apple mango banana fare magenta)
len=${#array[*]}
echo "The array has $len members. They are:"
i=0
while [ $i -lt $len ]; do
echo "$i: ${array[$i]}"
let i++
done

The len variable will represent the number of values in array and the loop will round till it completes the name of the members.

[SalVatore]

Defining variable with Bash shell :

The Declaration of variable for bash shell is quite simple,The variable is doesn't depends on the type,whatever value you will accepted by the variable.I am going to show you an example which will show the declaration of the variable :


Var=1
while [ $n -le 6 ]; do
echo $n
let n++
done

Use this given code above to create a variable.The variable is declared named var and an integer value is assigned in the variable.While loop is being used to execute find the increased value of 1 at 6 times.

[Dr. V]

Executing a program with Bash shell :

When you would be prepare to create a program you need a platform for creation and you can choose the notepad or any editor like :Vi or nano.

After creating you need to save it with .sh extension as a post fix of the file.To execute the file of bash.It is necessary to know on which shell you are working currently and follow the below code to execute a bash script.

The user script are always stored in the home directory of user and the user can use the ./ method to locate the home directory of a user.

$ ./myscript.sh

The ./ shows the current home directory of the user.

[Devasis]

Searching and Replacing Substrings within Strings :


Using this method you can replace one or more collection of string.The syntax is displayed here :

alpha="The youngsters are growing with \"Technology\" is replaced."
beta="${alpha/Technology/New Ideas}"

The beta variable contains some variables but after execution of this statement the Technology word would be changed into New ideas.
To replace all cases,you can // (Double hyphen) mark to initiate the changes
beta="${alpha//Technology/New Ideas}"

[Solomon]

Useful string operations in bash shell :

You can perform better operations with the strings operations within your script files.This concept can be used to write a long and useful script :

I am going to introduce with four operators in the scripting with bash shell :

Operator "#" - To delete the pair of words from the left of sentence
Operator "##" - To delete the two pairs of words from the left of sentence
Operator "%". - To delete the pair of words from the right of sentence
Operator "%%" - To delete the two pair of words from the right of sentence

These operators is being used to operate the string manipulations .