Bash Options -- gregmark, mark 1

bash-options-gregmark-I.sh

#!/bin/bash

# me
# ------------------------------------------------------------------------------
script=$(basename $0)
script_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &>/dev/null && pwd )"
script_path="${script_dir?}/${script}"


# error & usage
# ------------------------------------------------------------------------------
# google err function
gerr() {
  echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $*" >&2
}

err () {
    _rc=$1
    if [[ "${1}" =~ ^[1-9][0-9]*$ ]]; then
        shift
        (echo -n ERROR; [[ $# -ge 1 ]] && echo ": $@" || echo) >&2
        return ${_rc}
    else
        echo $@
    fi
    return 0
}

usage () {
    err $@ && _rc=$? && echo $_rc
    echo
    cat <<-EOF
    usage: ${script} [options]
    
EOF
    exit ${_rc:-0}
}
# option defaults
# ------------------------------------------------------------------------------
declare true=1 false=0
declare -A vars_default=(
    # boolean
    [bool]=${false}
    [verbose]=${false}
    [dryrun]=${false}
    [debug]=${false}
    # optargs
    [mutually]="foo"
    [exclusive]="bar"
    [string]=""
)

array_copy() {
    set -- "$(declare -p $1)" "$2"
    eval "$2=${1#*=}"
}

declare -A vars
array_copy vars_default vars

# option parsing
# ------------------------------------------------------------------------------
read_optarg () {
  _params="$@"d
  if [ -n "$2" ] && [ ${2:0:1} != "-" ]; then
    echo $2
  else
    echo "Error: Argument for $1 is missing" >&2
    exit 1
  fi
}

PARAMS=""
while (( "$#" )); do
  case "$1" in
    -b|--bool)
      vars[bool]=${true} ;
      shift ;
      ;;
    -m|--mutually)
      vars[mutually]=${true} && vars[exclusive]=${false} ;
      shift ;;
      ;;
    -e|--exclusive)
      vars[exclusive]="true" && vars[mutually]= && shift
      ;;
    -s|--string)
      vars[string]="$(read_optarg $@)" ;
      shift 2 ;
      ;;
     -v|--verbose)
      vars[verbose]=${true} ;
      shift ;
      ;;
    -n|--dryrun)
      vars[dryrun]=${true} ;
      shift ;
      ;;
    -d|--debug)
      vars[debug]=${true} ;
      shift ;
      ;;
    -h|--help)
      usage 0 && shift
      ;;
    -*|--*=) # unsupported flags
      echo "Error: Unsupported flag $1" >&2
      exit 1
      ;;
    *) # preserve positional arguments
      PARAMS="$PARAMS $1" && shift
      ;;
  esac
done
eval set -- "$PARAMS"