Handling Multiple Conditions in Bash Scripts

Discover diverse examples of case statements in Bash scripts, offering insights into handling multiple conditions efficiently.

From simple patterns to complex pattern matching and command output, these examples demonstrate the versatility of case statements in Bash. Whether you're a beginner or an experienced scripter, these examples provide valuable techniques for enhancing script functionality and managing various scenarios effectively.

Simple Case Statement with Single Pattern

fruit="apple"

case $fruit in
    "apple")
        echo "It's an apple."
        ;;
esac

Case Statement with Multiple Patterns

fruit="banana"

case $fruit in
    "apple" | "banana")
        echo "It's either an apple or a banana."
        ;;
esac

Case Statement with Pattern Ranges

num=5

case $num in
    [1-5])
        echo "The number is between 1 and 5."
        ;;
esac

Case Statement with Wildcard Pattern

filename="example.txt"

case $filename in
    *.txt)
        echo "It's a text file."
        ;;
esac

Case Statement with Pattern Matching using Regular Expressions

name="John"

case $name in
    [A-Z][a-z]*)
        echo "It's a capitalized name."
        ;;
esac

Case Statement with Fallthrough

fruit="orange"

case $fruit in
    "apple")
        echo "It's an apple."
        ;;
    "orange" | "banana")
        echo "It's an orange or a banana."
        # Fallthrough
        ;;
    "mango")
        echo "It's a mango."
        ;;
esac

Case Statement with a Default Case

fruit="watermelon"

case $fruit in
    "apple")
        echo "It's an apple."
        ;;
    "orange")
        echo "It's an orange."
        ;;
    *)
        echo "It's an unknown fruit."
        ;;
esac

Case Statement with Variable Substitution

fruit="apple"

case ${fruit^^} in
    "APPLE")
        echo "It's an uppercase apple."
        ;;
esac

Case Statement with Complex Pattern Matching

fruit="grape"

case $fruit in
    [a-z]*[aeiou])
        echo "It's a fruit with a vowel ending."
        ;;
    [A-Z]*)
        echo "It's a capitalized fruit."
        ;;
    *)
        echo "It's an unknown fruit."
        ;;
esac

Case Statement with Command Output

fruit=$(echo "apple" | tr '[:lower:]' '[:upper:]')

case $fruit in
    "APPLE")
        echo "It's an uppercase apple."
        ;;
esac