function ls(path,opts_in)
    local opts={
        msglimit=50,
        msgtimeout=100000,
    }
    if opts_in then
        for k,v in pairs(opts_in) do
            opts[k]=v
        end
    end
    local t,msg=os.listdir(path,opts.listall)
    if not t then
        return false,msg
    end
    local b=msg_batcher{
        batchsize=opts.msglimit,
        timeoute=opts.msgtimeout
    }
    if path=='A/' then
        path = 'A'
    end
    for i,v in ipairs(t) do
        if not opts.match or string.match(v,opts.match) then
            if opts.stat then
                local st,msg=os.stat(path..'/'..v)
                if not st then
                    return false,msg
                end
                if opts.stat == '/' then
                    if st.is_dir then
                        b:write(v .. '/')
                    else
                        b:write(v)
                    end
                elseif opts.stat == '*' then
                    st.name=v
                    b:write(st)
                end
            else
                b:write(t[i])
            end
        end
    end
    b:flush()
    return true
end