Flickr upload directory (Linux)

#!/usr/bin/env lua5.1
-- requires flickcurl and jhead installed, also libimage-exiftool-perl
require("lfs") --sudo apt-get install liblua5.1-filesystem0
local directory = "/home/fuxoft/Pictures/upload/"
local extensions = {"jpg","jpeg","gif","png","tif","tiff"}

assert(directory:match("/$"),"No trailing slash in directory name")

local function is_jpeg(fname)
    return string.lower(fname):match("%.jpe?g$")
end

local function is_image(fname)
    local lower = fname:lower()
    for i, ext in ipairs(extensions) do
        if lower:match("%."..ext.."$") then
            return true
        end
    end
    return false
end

local function print_size(num)
    num = num / 1000000
    return (math.floor(num*10+0.5)/10).." MB"
end

local function print_time(num)
    num = math.floor(num + 0.5)
    return string.format("%d:%02d",math.floor(num/60),num % 60)
end

--Find Instagram files and set EXIF date from their filenames
for fname in lfs.dir(directory) do
    local year, month, day, hour, min, sec = fname:match("IMG_(%d%d%d%d)(%d%d)(%d%d)_(%d%d)(%d%d)(%d%d).jpg")
    if sec then
        year = tonumber(year)
        assert(year >= 2012 and year<2030, "Bad year: "..year)
        local fullname = directory..fname
        print("Instagram: "..fname)
        os.execute("jhead -mkexif "..fullname)
        os.execute(string.format("jhead -ts%s:%s:%s-%s:%s:%s %s",year, month, day, hour, min, sec, fullname))
        os.execute("exiftool -overwrite_original -keywords=instagram "..fullname)
        --print(fname)
        local fullname = directory..fname
    end
end
--os.exit()

--rename all files
print("Autorotating.....")
local stat = os.execute("jhead -autorot "..directory.."*")
print("Renaming.....")
local stat = os.execute("jhead -np_%Y-%m-%d_%H-%M-%S "..directory.."*")
--assert(stat == 0, "Jhead error, stat = "..stat)

local files = {}
local totalsize = 0
for fname in lfs.dir(directory) do
    if fname ~= "." and fname ~= ".." then
        --print(fname)
        local fullname = directory..fname
        --print(lfs.attributes(fullname,"mode"))
        local attrs = lfs.attributes(fullname)
        if not (attrs.mode=="file" and is_image(fname)) then
            print("Ignoring: "..fname)
        else --Rename
            --print("ok")
            local size = attrs.size
            table.insert(files,{fname = fname, fullname = fullname,size=size})
            totalsize = totalsize + size
        end
    end
end

table.sort(files, function(a,b) return a.fname < b.fname end)

local remainsize = totalsize
local uplsize = 0
local timestart = os.time()
for i,file in ipairs(files) do
    print("Uploading "..i.."/"..(#files).." ("..print_size(file.size).."): "..file.fname)
    repeat
        local status_ok = 0 == os.execute(string.format('flickcurl upload "%s" public 2> /dev/null',file.fullname))
        if not status_ok then
            print("* ERROR * Retrying...")
        end
        assert(os.execute("sleep 0.1")==0,"User abort")
    until status_ok
    remainsize = remainsize - file.size
    uplsize = uplsize + file.size
    local timedone = os.time() - timestart
    local done_pct = uplsize / totalsize
    local timetotal = timedone / done_pct
    local timeremain = timetotal - timedone
    print("----UPLOAD OK---- Remaining: "..print_time(timeremain).." ("..print_size(remainsize)..", "..math.floor(100-done_pct*100+0.5).."%)")
    os.remove(file.fullname)
end
print("************** ALL DONE **************")
os.execute("sleep 9")