Writing Bash Script

Bash scripting is a powerful tool that allows you to automate tasks, streamline processes, and enhance your productivity as a developer or system administrator. Understanding the fundamentals of writing Bash scripts is essential for anyone seeking to harness the full potential of the command line interface. This article will explore the basics of writing Bash scripts, covering important concepts such as the Bash symbol, shebang, script commands, and chaining multiple commands.

Key Takeaways

• Getting familiar with the process of writing Bash script.
• Getting familiar with the utilities of Bash script.

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Step-by-Step Guide to Write a Bash Script

While programmers write Bash script, they follow some steps sequentially. Here, I have discussed these steps briefly.

1. Getting Started: Initiating a Bash Script

To begin writing a Bash script, open a text editor and create a new file with the “.sh” extension. This extension is commonly used to indicate that the file contains a Bash script. At the start of your script, it is important to include the “shebang” line.

2. The Shebang Line: #!/bin/bash

The shebang line, also known as the shebang or the interpreter directive, informs the system which interpreter should be used to execute the script. In the case of the Bash script, the shebang line is “#!/bin/bash”. This line should always be the first line of your script.

3. Bash Script Commands

Bash script allows you to execute commands and perform various operations. Examples of commonly used Bash Script commands are echo, read, if, else, and elif. There are some special symbols for chaining commands which help the programmer execute multiple commands in a single line.

Some Practical Examples of Writing a Bash Script

In this section, I have demonstrated some sample Bash scripts that will help you to understand the basic concept of a Bash script.

Example 01: Printing a Greetings on the Terminal

Here I will develop a Bash script that will print a greeting on the terminal. To do so, follow the below procedures.

Steps to Follow >

❶ At first, launch an Ubuntu Terminal.

❷ Write the following command to open a file in Nano:

nano sample.sh

❸ Copy the script mentioned below:

#!/bin/bash

echo"Happy Scripting" #prints the greetings on the terminal

❹ Press CTRL+O and ENTER to save the file; CTRL+X to exit.

❻ Run the script by the following command:

bash sample.sh

The above image shows that Bash script has printed a greeting text on the terminal.

Example 02: Taking Input From the User Then Print It

You can take input from the user while running a Bash script and then print it on the terminal. Here I have developed a Bash script that takes input from the user and then prints it on the terminal. To do this task, follow the below script.

Script (bash.sh) >

#!/bin/bash

#takeing input from users
read -p "What is your name?: " name

#printing on the terminal
echo "Welcome $name!"

Execute the following command into the terminal to make the Bash script executable.

chmod +x bash.sh

Run the script by the following command:

./bash.sh

In the above image, you can see that the Bash script has taken input from the user and then printed it on the terminal.

Example 03: Performing Arithmetic Operations by Taking Two Input Numbers from the User

Programmers can do arithmetic operations on the Bash script. Here, I have developed a Bash script that takes two inputs from the user and then does an arithmetic summation. Afterward, print the summation on the terminal. To do so, follow the below script.

Script (arith.sh) >

#!/bin/bash

#taking number as input from user
read -p "Enter First Number: " a
read -p "Enter Second Number: " b

#calculation summation
var=$((a+b))

#printing the summation value
echo "Summation of The Two Number:$var"

Run the script by the following command:

./arith.sh

The above image shows that the Bash script has taken input from the user then done an arithmetic summation.

Example 04: Using a Function in the Bash Script

You can easily use a function in the Bash script. Here, I have developed a Bash script where the function is used to print a message. To do so, follow the below script.

Script (bash_fun.sh) >

#!/bin/bash

# A sample bash function
sample_function () {
echo "Good Morning!"
}

# Invoking the sample_function
sample_function

Run the script by the following command:

./bash_fun.sh

The above image shows that the Bash script has printed a message using a function.

Conclusion

Writing Bash script empowers you to automate repetitive tasks, manage complex operations, and boost your efficiency as a developer or system administrator. By understanding the fundamentals of Bash scripting, including the Bash symbol, shebang, script commands, and chaining multiple commands, you can create powerful scripts to streamline your workflow. Embrace the power of Bash scripting, and unlock new possibilities in the command line realm.

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• How Will You Start Writing Bash Scripts [A Complete Overview]
• An Ultimate Guide to Bin Bash Script and Shebang
• Most Used Bash Script Commands [The Ultimate Review]
• 16 Most Used Symbols for Bash Script
• 8 Practical Examples of Chaining Commands in Bash Scripts

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