pub fn open(filename: string, mode: option<string>) -> option<file>Expand description
Opens a file.
§Parameters
filename: the name of the file to open.mode: the open mode:"r"(read — the default),"w"(write, truncating),"a"(append), or the update modes"r+","w+","a+". Any of them may be followed by"b"to open in binary mode on systems where it matters.
§Return value
A new file handle, or, in case of errors, nil plus an error message
and a system-dependent error code. A common idiom wraps the call in
assert to turn a failed open into an error.
§Examples
local f = assert(io.open("out.txt", "w"))
f:write("hello\n")
f:close()