bash script to follow a given url to its final destination, i.e. to unshorten URLs or follow-through redirects to the ultimate destination URL

url_final.sh

#!/bin/bash

# Function to parse command line arguments
parse_args() {
    while [[ $# -gt 0 ]]; do
        case $1 in
            -u=*|--url=*)
                URL="${1#*=}"
                shift # past argument=value
                ;;
            *)
                echo "Invalid option: $1"
                exit 1
                ;;
        esac
    done

    if [ -z "$URL" ]; then
        echo "Error: --url is required."
        echo "Usage: $0 --url <URL>"
        exit 1
    fi
}

# Function to get the final URL after following redirects
get_final_url() {
    if ! FINAL_URL=$(curl -Ls -o /dev/null -w %{url_effective} "$URL"); then
        echo "Error fetching final URL for: $URL"
        exit 1
    fi
    echo "$FINAL_URL"
}

# Main script execution
parse_args "$@"

get_final_url