checksum.sh

#!/bin/bash

if [ "$#" -ne 2 ]; then
    echo "Usage: $0 <file_path> <md5|sha256>"
    exit 1
fi

file_path="$1"
algorithm="$2"

if [ ! -f "$file_path" ]; then
    echo "Error: File not found!"
    exit 1
fi

if ! command -v md5sum &> /dev/null || ! command -v openssl &> /dev/null || ! command -v xxd &> /dev/null; then
    echo "Error: Required utilities (md5sum, openssl or xxd) not found."
    exit 1
fi

case "$algorithm" in
md5)
    # Checksum md5
    # MD5 hash > convert to binary > encode in base64 without padding
    hash=$(cat "$file_path" | md5sum | awk '{print $1}' | xxd -r -p | base64 | sed 's/=//g')
    ;;
sha256)
    # SubResource Integrity sha256
    # SHA-256 hash > convert to binary > encode in base64 without padding
    hash=$(cat "$file_path" | openssl dgst -sha256 -binary | openssl base64 | sed 's/=//g')
    ;;
*)
    echo "Error: Use 'md5' or 'sha256'."
    exit 1
    ;;
esac

echo "$hash"