Bash script example arguments / flags

script.sh

#!/bin/bash

opts_count=0
while getopts g:n: flag
do
    case "${flag}" in
        g)                      greeting=${OPTARG}; ((opts_count=opts_count+1)) ;;
        n)                          name=${OPTARG}; ((opts_count=opts_count+1)) ;;
        *)                              echo "Unknown parameter passed"; exit 1 ;;
    esac
done

usage(){
    echo "**Sample Script***"
    echo "Usage: ./script.sh -g Hello -n World"
    echo "---Parameters---"
    echo "g=    :greeting"
    echo "n=    :name"
}

start() {
  echo "$greeting $name"
}

# Exit program if we don't get  arguments
[[ $opts_count < 2 ]] && { usage && exit 1; } || start