An example of a bash script that has required arguments

getops.sh

#!/usr/bin/env bash

# e (errexit): Abort script at first error
# u: Treat unset variables as an error
# f: Disable filename expansion (globbing) upon seeing *, ?, etc..
# pipefail: Causes a pipeline to return exit code for last command in pipe
set -euf -o pipefail

# run this if the script exits with a non-zero exit code
handle_error() {
	echo "We got an error... so do some cleanup..."
	# Additional error handling logic
	exit 1
}

# set the error handler function
trap handle_error ERR

if [ $OPTIND -eq 1 ]; then
    echo "No options were passed"
    exit 1
fi

while getopts a:b:c: option
do
    case "${option}"
    in
        a) A=${OPTARG};;
        b) B=${OPTARG};;
        c) C=${OPTARG};;
        # there are options but no matches
        *) echo "Usage: getops.sh -a A -b B -c C" >&2
           exit 1;;
    esac
done

# we made it past the guards!
echo "A=$A B=$B C=$C"

exit 0