Shell Scripting for Beginners: Automate Tasks Like a Pro

Intro du ction

Sh ell scriptin g is a po wer ful tool that h elps automate r epetitive ta sks i n Linux and macOS environmen ts. Whether you're a developer, syst e m adm inistrator, or just a te ch e nthusiast, learni ng shell scriptin g ca n save you time and eff or t. In th is guide , we'll brea k down shell scrip ting in simple terms with practical exa mples.

Wh at is Shell Scripting?

A shell script is a file containing a series of commands that the shell (command-line interface) executes. It helps automate tasks like file manipulation, system monitoring, and batch processing.

Getting Started

1. Creating Your First Shell Script

To create a shell script, follow these steps:

Open a terminal.
Create a new file with a .sh extension:
```
 touch myscript.sh
```
Open the file in a text editor (e.g., nano, vim, or VS Code):
```
 nano myscript.sh
```
Add the following script:
```
 #!/bin/bash
 echo "Hello, World!"
```
Save the file and exit the editor.

2. Making the Script Executable

Before running the script, you need to give it execute permissions:

chmod +x myscript.sh

3. Running the Script

Run the script using:

./myscript.sh

You should see:

Hello, World!

Understanding the Script

#!/bin/bash → This is called a shebang. It tells the system to use the Bash shell to interpret the script.
echo "Hello, World!" → Prints text to the terminal.

Variables in Shell Scripting

You can store values in variables and use them in your script.

#!/bin/bash
name="John Doe"
echo "Hello, $name!"

Output:

Hello, John Doe!

Taking User Input

#!/bin/bash
echo "Enter your name: "
read user_name
echo "Welcome, $user_name!"

Conditional Statements

#!/bin/bash
echo "Enter a number: "
read num
if [ $num -gt 10 ]
then
   echo "The number is greater than 10."
else
   echo "The number is 10 or less."
fi

Looping in Shell Scripts

For Loop

#!/bin/bash
for i in {1..5}
do
   echo "Number: $i"
done

While Loop

#!/bin/bash
count=1
while [ $count -le 5 ]
do
   echo "Count: $count"
   ((count++))
done

Functions in Shell Scripting

#!/bin/bash
say_hello() {
   echo "Hello, $1!"
}
say_hello "Alice"
say_hello "Bob"