Shell Script to Split a String

Shell Scripting or Shell Programming is just like any other programming language. A shell is a special program that provides an interface between the user and the operating system.

In Linux/Unix the default shell used is bash and in windows, it is cmd(command prompt). We use the terminal to run a shell command. Shell scripts are saved with .sh file extension, and we can run the script with the help of the following command.

bash path/to/the/filename.sh

Example:

A simple shell program to print Hello Geeks!!.

#! /bin/bash

# echo is used to print
echo "Hello Geeks!!"

Here, #! /bin/bash is used to let know the Linux/Unix that it is a Bash Script and use the bash interpreter which resides in /bin to execute it.

Output:

First Shell Program

Shell Script to Split a String:

Let’s discuss how we can split a string take the following string for an example:

string  = “Lelouch,Akame,Kakashi,Wrath”

And we would like to split the string by “,” delimiter  so that we have :

• name=”Lelouch”
• name =”Akame”
• name=”Kakashi”
• name=”Wrath”

Approach 1: Using IFS (Input Field Separator).

IFS stands for Internal Field Separator or Input Field separator variable is used to separate a string into tokens.

Original String : 

string=”Lelouch,Akame,Kakashi,Wrath”

After Splitting :

name = Lelouch

name = Akame

name = Kakashi

name = Wrath

String holds the input string value and IFS variable the delimiter on that we are going to separate the string. read -ra arr <<< “$string” convert the separated strings into an array, after that we are using for loop to traverse the array and print the value.“@” in arr subscript shows that we are going through the whole array.

Script :

#! /bin/bash

# Given string 
string="Lelouch,Akame,Kakashi,Wrath"

# Setting IFS (input field separator) value as ","
IFS=','

# Reading the split string into array
read -ra arr <<< "$string"

# Print each value of the array by using the loop
for val in "${arr[@]}";
do
  printf "name = $val\n"
done

To run the script use the following command :

bash path/to/the/filename.sh

Output:

Script Output

Approach 2: Without using the IFS

 Suppose input string is containing a particular word “anime” and we want to split the string on seeing “anime”

string = “anime Bleach anime Naruto anime Pokemon anime Monster anime Dororo”

Output :

Anime name is = Bleach

Anime name is = Naruto

Anime name is = Pokemon

Anime name is = Monster

Anime name is = Dororo

We can do this using Parameter Expansion.

Script :

#! /bin/bash

# Given string 
string="anime Bleach anime Naruto anime Pokemon anime Monster anime Dororo"

# Syntax to replace all occurrences of "anime" with " "
arr=(${string//"anime"/ })

# Print each value of the array by using the loop
for val in "${arr[@]}";
do

  printf "Anime name is = $val\n"
done

Output:

Script Output