Control Flow.md

In Bash scripting, control flow structures allow you to make decisions and control the flow of execution in your script. Here are key control flow structures:

1. if-else Statements:

#!/bin/bash

# Prompt the user for a number
echo -n "Enter a number: "
read num

# Check if the number is positive, negative, or zero
if [ $num -gt 0 ]; then
    echo "The number is positive."
elif [ $num -lt 0 ]; then
    echo "The number is negative."
else
    echo "The number is zero."
fi

In this example:

• if checks if the number is greater than 0.
• elif (else if) checks if the number is less than 0.
• else covers the case when the number is zero.

2. for Loop:

#!/bin/bash

# Iterate over a range of numbers
for i in {1..5}; do
    echo "Iteration $i"
done

This script uses a for loop to iterate from 1 to 5, and the variable i takes on each value in the specified range.

3. while Loop:

#!/bin/bash

# Initialize a counter
counter=1

# Use a while loop to count up to 5
while [ $counter -le 5 ]; do
    echo "Count: $counter"
    ((counter++))
done

Here, a while loop is used to increment a counter from 1 to 5.

4. case Statement:

#!/bin/bash

# Prompt the user for a color
echo -n "Enter a color (red, green, or blue): "
read color

# Check the color using a case statement
case $color in
    "red")
        echo "Roses are red."
        ;;
    "green")
        echo "Grass is green."
        ;;
    "blue")
        echo "The sky is blue."
        ;;
    *)
        echo "Not a recognized color."
        ;;
esac

The case statement checks the value of the color variable against various patterns and executes the corresponding block of code.

These control flow structures provide the foundation for decision-making and looping in Bash scripts. They allow you to create more complex and responsive scripts based on different conditions and scenarios.