username:ABCDEFG   (tab)   # comment [exp:YYYY-MM-DD]

# loop through each line of htpasswd
(
    while read line; do            
        # extract the username from the line
        line_user=$(echo `echo "$line" | cut -d: -f1`)
        [ -n "$VERBOSE" ] && echo "Checking expiry of user '$line'" >&2
        
        # extract the expiry date from the line
        line_date=$(echo `echo "$line" | grep -o "\[exp:[0-9]\{4\}-[0-9]\{2\}-[0-9]\{2\}\]" | grep -o "[0-9]\{4\}-[0-9]\{2\}-[0-9]\{2\}"`)

        if [ -n "$line_date" ]; then
            EXPIRED=
            
            # break the expiry date into a year, month and date
            line_year=$(echo `echo "$line_date" | cut -d- -f1`)
            line_month=$(echo `echo "$line_date" | cut -d- -f2`)
            line_date=$(echo `echo "$line_date" | cut -d- -f3`)
            
            if [ $line_year -lt $today_year ]; then
                EXPIRED=1
            elif [ $line_year -eq $today_year ]; then
                if [ $line_month -lt $today_month ]; then
                    EXPIRED=1
                elif [ $line_month -eq $today_month ]; then
                    if [ $line_date -lt $today_date ]; then
                        EXPIRED=1
                   fi
                fi
            fi
            
            if [ -z "$EXPIRED" ]; then
                # not expired, output the user back to htpasswds
                echo "$line"
            else
                [ -n "$VERBOSE" ] && echo "User has expired. Deleting..." >&2
                
                echo "Haven't yet implemented deleting user from htgroups. This needs to be done manually!" >&2
                # also delete the user from htgroups
                #(
                #    while read line2; do
                #        #new_group=$(echo `echo "$line2" | grep -o "^[^#].*:*\[ $line_user \]" | grep -o "^[^#].*:*\[$line_user \]" | grep -o "^[^#].*:*\[ $line_user\]"sed 's/^[^#].*:$/'`)
                #    done < $HTGROUPS
                
                #) > $HTGROUPS.tmp    
            fi
        else
            # user doesn't have an expiry date, output the user back to htpasswds
            echo "$line"
        fi
    done < $HTPASSWD
) > $HTPASSWD.tmp

# move temp file
rm -f $HTPASSWD
mv $HTPASSWD.tmp $HTPASSWD