function getopt(arg, opts)
    result = {}
    processed = {}
    for i = 1, arg.n do
        if (string.sub(arg[i], 1, 1) == "-") then
            for j = 2, string.len(arg[i]) do
                opt = string.sub(arg[i], j, j)
                find = string.find(opts, opt)
                if find ~= nil then
                    if string.sub(opts, find+1, find+1) == ":" then
                        -- opt takes an arg
                        if string.len(arg[i]) > 2 then
                            -- opt takes an arg, arg directly follows opt
                            result[opt] = string.sub(arg[i], 3)
                            processed[i] = 1
                            break
                        elseif arg.n >= (i+1) then
                            -- opt takes an arg, arg must be next arg in list
                            result[opt] = arg[i+1]
                            processed[i] = 1
                            processed[i+1] = 1
                        else
                            -- opt takes an arg, but was not given one
                            print("Option requires an argument: -" .. opt)
                            result[opt] = 1
                            processed[i] = 1
                        end
                    else
                        -- opt does not take an arg
                        result[opt] = 1
                        processed[i] = 1
                    end
                else
                    -- unknown opt
                    print("Unrecognized option -" .. opt)
                    processed[i] = 1
                end
            end
        end
    end
    -- remove whatever options we've processed
    for i = arg.n,1,-1 do
        if processed[i] then
            table.remove(arg,i)
        end
    end
    return result
end