File Module

Close a file and release all related resources. When you are done reading a file, close it to prevent a resource leak and let other processes read the file.

Flush any buffered bytes to the file system. In most files, writes are buffered for efficiency reasons. Returns the file handle.

Open a file. `path` is an absolute or relative path, and `mode` is a set of flags indicating the mode to open the file in. `mode` is a keyword where each character represents a flag. If the file cannot be opened, returns nil, otherwise returns the new file handle. Mode flags:

* r - allow reading from the file

* w - allow writing to the file

* a - append to the file

Following one of the initial flags, 0 or more of the following flags can be appended:

* b - open the file in binary mode (rather than text mode)

* + - append to the file instead of overwriting it

* n - error if the file cannot be opened instead of returning nil

Read a number of bytes from a file `f` into a buffer. A buffer `buf` can be provided as an optional third argument, otherwise a new buffer is created. `what` can either be an integer or a keyword. Returns the buffer with file contents. Values for `what`:

* :all - read the whole file

* :line - read up to and including the next newline character

* n (integer) - read up to n bytes from the file

Jump to a relative location in the file `f`. `whence` must be one of:

* :cur - jump relative to the current file location

* :set - jump relative to the beginning of the file

* :end - jump relative to the end of the file

By default, `whence` is :cur. Optionally a value `n` may be passed for the relative number of bytes to seek in the file. `n` may be a real number to handle large files of more than 4GB. Returns the file handle.

Get the current value of the file position for file `f`.

Open an anonymous temporary file that is removed on close. Raises an error on failure.

Writes to a file. 'bytes' must be string, buffer, or symbol. Returns the file.