Bash — Arguments

Positional parameters

#!/bin/bash

echo "Script: $0"
echo "First arg: $1"
echo "Second arg: $2"
echo "All args: $@"
echo "Number of args: $#"

Default values

#!/bin/bash

name="${1:-World}"
echo "Hello, $name!"

Shift

#!/bin/bash

while [ $# -gt 0 ]; do
    echo "Processing: $1"
    shift
done

Named arguments

#!/bin/bash

while [[ $# -gt 0 ]]; do
    case $1 in
        -n|--name)
            name="$2"
            shift 2
            ;;
        -a|--age)
            age="$2"
            shift 2
            ;;
        *)
            echo "Unknown: $1"
            shift
            ;;
    esac
done

echo "Name: $name, Age: $age"

Mini Practice

Write Bash code that:

1. Prints all arguments
2. Uses default values for missing arguments
3. Processes arguments with shift
4. Handles named arguments with a case statement

Up Next

In the next lesson, you'll learn about Exit Codes — returning status from scripts.