options parsing in bash

a.bash

declare -A FLAGS                                                                                                                                                                                                                                                
declare -a ARGS                                                                                                                                                                                                                                                 
while [[ $# -gt 0 ]]; do                                                                                                                                                                                                                                        
    key="$1"                                                                                                                                                                                                                                                    
    case $key in                                                                                                                                                                                                                                                
        -h|--help)                                                                                                                                                                                                                                              
            FLAGS[--help]=1                                                                                                                                                                                                                                     
            shift                                                                                                                                                                                                                                               
            ;;                                                                                                                                                                                                                                                  
        -p|--pause)                                                                                                                                                                                                                                             
            FLAGS[--pause]=1                                                                                                                                                                                                                                    
            shift                                                                                                                                                                                                                                               
            ;;                                                                                                                                                                                                                                                  
        *)                                                                                                                                                                                                                                                      
            if [[ "$1" = --no-* ]]                                                                                                                                                                                                                              
            then                                                                                                                                                                                                                                                
                FLAGS[$1]=1                                                                                                                                                                                                                                     
                shift                                                                                                                                                                                                                                           
            elif [[ "$1" = --* ]]                                                                                                                                                                                                                               
            then                                                                                                                                                                                                                                                
                FLAGS[$1]=1                                                                                                                                                                                                                                     
                STEPS=1                                                                                                                                                                                                                                         
                shift                                                                                                                                                                                                                                           
            elif [[ "$1" = -* ]]                                                                                                                                                                                                                                
            then                                                                                                                                                                                                                                                
                echo "Error: unknown flag $1, use double-hypen for step flags"                                                                                                                                                                                  
                exit 1                                                                                                                                                                                                                                          
            else                                                                                                                                                                                                                                                
                ARGS+=("$1")                                                                                                                                                                                                                                    
                shift                                                                                                                                                                                                                                           
            fi                                                                                                                                                                                                                                                  
            ;;                                                                                                                                                                                                                                                  
    esac                                                                                                                                                                                                                                                        
done                                                                                                                                                                                                                                                            
if [[ ${FLAGS[--help]} = 1 ]]; then usage; exit; fi                                                                                                                                                                                                             
                                                                                                                                                                                                                                                                
hostname="${ARGS[0]:-foo}"                                                                                                                                                                                                                                      
adminemail="${ARGS[1]:-bar}"