Getopts Wrapper

getopts_extended

#!/bin/bash                                                                          

# Extended version of getopts, which cannot handle both optional/non-optional        
# parameters in a combined manner (non-optional ones can't come first.)              
# This function allows us to do it and we can parse all of the followings:           
#   ./cmd -a optarg_for_a -b arg1                                                    
#   ./cmd -a optarg_for_a arg1 -b                                                    
#   ./cmd arg1 -a optarg_for_a -b                                                    
#                                                                                    
# The usage of getopts_extended is similar to that of getopts like:                  
#   getopt_extended "ab:c" [retcode] "$@"                                            
#                                                                                    
# Note:                                                                              
#  - the last argument for getopt_extended should be double-quoted,                  
#    otherwise long non-optional arguments (strings with multiple words              
#    like "a b c") are considered as separated.                                      
#  - getopts_extended returns '?' when non-optional arguments come,                  
#    then parsed arguments is stored in OPTARG.                                      
getopts_extended() {
    local optstring=$1
    local retcode=$2
    shift 2
    local argnum=$#

    # Return if we already finished up argument parsing.                             
    [ $OPTIND -gt $argnum ] && return 1

    getopts $optstring $retcode $@
    local ret=$?
    if [ $ret -ne 0 ] ; then # for non-optional arguments                            
        eval OPTARG=\${$OPTIND}
        words=`echo $OPTARG | wc -w`
        OPTIND=$[OPTIND + words]
    fi
    return 0
}

while getopts_extended "a:b" opt "$@" ; do
    case $opt in
        a) echo "opt -a $OPTARG" ;;
        b) echo "opt -b $OPTARG" ;;
        \?) echo "args [$OPTARG]"
    esac
done