#!/bin/bash
 
while getopts ":a:" opt; do
  case $opt in
    a)
      echo "-a was triggered, Parameter: $OPTARG" >&2
      ;;
    \?)
      echo "Invalid option: -$OPTARG" >&2
      exit 1
      ;;
    :)
      echo "Option -$OPTARG requires an argument." >&2
      exit 1
      ;;
  esac
done

-t|--target) [ $targets_changed == false ] && REP_TARGETS="" && targets_changed=true; REP_TARGETS="$REP_TARGETS $2"; shift 2 ;;
--cflags) [ $cflags_changed == false ] && REP_CFLAGS="" && cflags_changed=true; REP_CFLAGS="$REP_CFLAGS $2"; shift 2 ;;
--cxxflags) [ $cxxflags_changed == false ] && REP_CXXFLAGS="" && cxxflags_changed=true; REP_CXXFLAGS="$REP_CXXFLAGS $2"; shift 2 ;;
--ldflags) [ $ldflags_changed == false ] && REP_LDFLAGS="" && ldflags_changed=true; REP_LDFLAGS="$REP_LDFLAGS $2"; shift 2 ;; 

TEMP=`getopt -o hS:P:I:l:c:x:t: --long help,sources:,package:,include:,libs:,cc:,cxx:,target:,cflags:,cxxflags:,ldflags: -- "$@"`
eval set -- "$TEMP" 

$ cat /usr/share/getopt/getopt-parse.bash 
#!/bin/bash

# A small example program for using the new getopt(1) program.
# This program will only work with bash(1)
# An similar program using the tcsh(1) script language can be found
# as parse.tcsh

# Example input and output (from the bash prompt):
# ./parse.bash -a par1 'another arg' --c-long 'wow!*\?' -cmore -b " very long "
# Option a
# Option c, no argument
# Option c, argument `more'
# Option b, argument ` very long '
# Remaining arguments:
# --> `par1'
# --> `another arg'
# --> `wow!*\?'

# Note that we use `"$@"' to let each command-line parameter expand to a 
# separate word. The quotes around `$@' are essential!
# We need TEMP as the `eval set --' would nuke the return value of getopt.
TEMP=`getopt -o ab:c:: --long a-long,b-long:,c-long:: \
     -n 'example.bash' -- "$@"`

if [ $? != 0 ] ; then echo "Terminating..." >&2 ; exit 1 ; fi

# Note the quotes around `$TEMP': they are essential!
eval set -- "$TEMP"

while true ; do
	case "$1" in
		-a|--a-long) echo "Option a" ; shift ;;
		-b|--b-long) echo "Option b, argument \`$2'" ; shift 2 ;;
		-c|--c-long) 
			# c has an optional argument. As we are in quoted mode,
			# an empty parameter will be generated if its optional
			# argument is not found.
			case "$2" in
				"") echo "Option c, no argument"; shift 2 ;;
				*)  echo "Option c, argument \`$2'" ; shift 2 ;;
			esac ;;
		--) shift ; break ;;
		*) echo "Internal error!" ; exit 1 ;;
	esac
done
echo "Remaining arguments:"
for arg do echo '--> '"\`$arg'" ; done