shasum checker bash script

check.sh

#!/bin/bash

if [ "$1" == "-h" ] || [ -z "$1" ]
then
  echo "$(basename "$0") [-h] [-f file] [-a algo] [-c hash] -- script to calculate and verify the shasums of the passed file

	where:
	    -h  show this help text
	    -f 	pass the file name
	    -a 	pass the algorithm to perform eg, 1 or 256 or 512
	    -c  pass the correct hash of the file"
	exit 0
fi

while getopts f:a:c: flag
do
    case "${flag}" in
        f) file=${OPTARG};;
        a) algo=${OPTARG};;
        c) hash=${OPTARG};;
    esac
done

hash_computed=($(shasum -a $algo $file))


if [[ "$hash" = "$hash_computed" ]]
then
	echo "The file is not tempered!"
else
	echo "The file integrity is tempered!"
fi