#!/bin/bash
# Script showing use of getopt and here documents
#
# This script allows options of -m, -i, or -h or --help
# It doesn't really do anything, but it does show
# sophisticated command line argument processing
# and several advanced shell programming features.
# Note the "-m" option has a required argument,
# as does the equivalent "--mode" option.
#
# Written 2005 by Wayne Pollock, Tampa Florida USA.

#set -x  # uncomment this line to turn on debug mode

PATH=/bin:/usr/bin

# This strips off the pathname info from the scriptname,
# ("$0"), leaving just the last (filename) part:
SCRIPTNAME=${0##*/}

# To avoid a lot of echo commands (and associated
# quoting issues) in some show_help function, you
# can use a "here" document.  A "here" document
# is an embedded file within the script.
# Here's a sample:

function show_help()
{
   cat <<-EOF
	$SCRIPTNAME: You are beyond any help,
	so stop annoying me!!!  :-)
	...
	EOF
}

# Parse out the args into a standard format:
ARGS=$(getopt -n $SCRIPTNAME -o m:ih -l mode:,help -- "$@")

# if the getopt detected an error, display help and quit:
if [ $? -ne 0 ]
then
    show_help
    exit 1;
fi

# Now reset the positional parameters:
# (The "eval" is needed in case any args were quoted by getopt.)
eval set -- $ARGS

# Handle each arg.  Usually this is a matter of setting
# some variable, to be tested later in the script.
# This loop processes each option, one at a time, until
# the end of options is found (marked with "--").  This
# code removes each arg as it is processed, so at the
# end, the positional parameters contain only the non-option
# command line args (for instance, filenames to work with):

M_OPT=0
M_ARG='<none>'
I_OPT=0

DONE=false
while [ "$DONE" != "true" ]
do
   case "$1" in
      -m|--mode)  let '++M_OPT'
                  case "$2" in
                  -*) echo "*** Missing argument: $1" >&2; exit 1;;
                  *)   M_ARG="$2"; shift ;;
                  esac
                  ;;

      -i)         let '++I_OPT' ;;

      -h|--help)  show_help     ;;

      --)         DONE=true     ;;

      *)          echo "***Illegal option: $1" >&2; exit 1 ;;

   esac

   shift  # this deletes $1 and resets the positional parameters
done

# At this point, the positional parameters contain the
# remaining command line arguments (not options), if any.

# Rest of script goes here: ...
echo M_OPT=$M_OPT, M_ARG=$M_ARG, I_OPT=$I_OPT
echo remaining cmd line args: $*