#!/bin/sh

arga=0
argb=0
argc=0

printUsage () {
    echo "\nSupported options:"
    echo   "------------------"
    echo "\t-a\targa\tDoes something called 'a'"
    echo "\t-b\targb\tDoes something called 'b'"
    echo "\t-c\targc\tDoes something called 'c'"
}

# cmd line options processing
processOptions () {
  while getopts "abc" optname
    do
      case "$optname" in
        "a")
          arga=1
          ;;
        "b")
          argb=1
          ;;
        "c")
          argc=1
          ;;
        *)
          printUsage
          exit
          ;;
      esac
    done
  return $OPTIND
}

processOptions "$@"

if [ "$arga" -eq "1" ]; then
    echo "-a was passed"
fi
if [ "$argb" -eq "1" ]; then
    echo "-b was passed"
fi
if [ "$argc" -eq "1" ]; then
    echo "-c was passed"
fi