How To Get the Size (In Bytes) Of A File Using Lua

Bytes.lua

-- This is a port of Bytes.go <https://gist.github.com/M1que4s/70965ab7ea03d85f43a379e0860d86eb>

function check(err, msg, ...)
	local msg = string.format(msg, ...)
	if err ~= nil then
		print(msg)
		return err
	end
end

function read_byte(filename)
	-- Holds the error
	local err, t = nil, {}

	-- Open the file, change the name for something in your system
	local file, err = io.open(filename, 'rb')
	check(err, 'Can\'t open file!')

	-- Reads the data from the file and returns them in an array
	repeat
		local str, err = file:read(4*1024)
		for b in (str or ''):gmatch'.' do
			t[#t+1] = b:byte()
		end
	until not str
	check(err, 'Can\'t read the file!')

	-- Prints the size!
	print(('File has %d bytes!\n'):format(#t))

	-- And close the file
	err = file:close()
	print('Can\'t close the file!')
end

-- Example of its use:
-- lua Bytes.lua <filename>

read_byte(arg[1])