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Operating System

This module implements a generic os interface. To function correctly it needs a filesystem to be mounted, so that the module can use the driver to access the underlying hardware.

Note

Every path needed as argument for an os function must follow chosen driver path convention. File/Directory access error due to low-level failure will raise an OSError.

exists

exists(path)

Return True if path refers to an existing path, False otherwise.

isdir

isdir(path)

Return True if path is an existing directory, False otherwise.

remove

remove(path)

Remove (delete) the file path. If path is a directory, OSError is raised; see rmdir() below to remove a directory.

rmdir

rmdir(path)

Remove (delete) the directory path. Only works when the directory is empty, otherwise, OSError is raised.

rename

rename(src_path, dst_path)

Rename the file or directory src_path to dst_path. If dst_path is a directory, OSError will be raised.

mkdir

mkdir(path)

Create a directory named path.

chdir

chdir(path)

Change the current working directory to path.

getcwd

getcwd()

Return a string representing the current working directory.

Since C filesystem drivers need a limit on returned string length:

os.cwd_max_length

attribute is set to 128 by default but can be adjusted, if needed, before calling getcwd().

listdir

listdir(path)

Return a list containing the names of the entries in the directory given by path. The list is in arbitrary order. It does not include the special entries ‘.’ and ‘..’ even if they are present in the directory.

copyfile

copyfile(src, dst)

Copy the contents of the file named src to a file named dst.

The FileIO class

FileIO

FileIO(path, mode = 'r')

Main class to handle files.

  • path is a string (following chosen low-level filesystem driver format)

  • mode is a string:

* r       open for reading (default)

* w       open for writing, truncating the file first

* a       open for writing, appending to the end of the file if it exists

* b       binary mode

* +       open a disk file for updating (reading and writing)
read

read(n_bytes = -1)

Read up to size bytes from the object and return them. As a convenience, if size is unspecified or -1, the whole file is read. Return type can be string or bytes depending on chosen mode.

An empty string or an empty bytes object indicate end of file.

write

write(to_w, sync = False)

Write to_w object (string or bytes) to the stream and return the number of characters written.

sync parameter allows to write changes to disk immediately, without waiting close() call.

close

close()

Close file stream.

size

size()

Return file size.

tell

tell()

Return the current stream position.

seek

seek(offset, whence=0)

Move the current position to offset bytes with respect to whence.

whence can be:

  • 0: start of file

  • 1: current position

  • 2: end of file

truncate

truncate()

Resize the stream to the given size in bytes (or the current position if size is not specified). The current stream position isn’t changed.

readline

readline()

Read until newline or EOF and return a single str. If the stream is already at EOF, an empty string is returned.