Processing shell script options

gistfile1.sh

unset OPTSTRING
unset OPTIND
local opt

while getopts "ab:c" opt; do
  case $opt in
    a)
      aSpecified=true
      ;;
    b)
      bValue=$OPTARG
      ;;
    c)
      cSpecified=true
      ;;
    ?)
      echo "Invalid option" > &2
  esac
done

# shift along so we can get at the arguments
shift `expr $OPTIND - 1`

unset OPTSTRING
unset OPTIND