This module provides a more portable way of using operating system
(OS) dependent functionality than importing an OS dependent built-in
module like posix or nt.
This module searches for an OS dependent built-in module like
mac or posix and exports the same functions and data
as found there. The design of all Python's built-in OS dependent
modules is such that as long as the same functionality is available,
it uses the same interface; e.g., the function
os.stat(path) returns stat information about path in
the same format (which happens to have originated with the
POSIX interface).
Extensions peculiar to a particular OS are also available through the
os module, but using them is of course a threat to
portability!
Note that after the first time os is imported, there is
no performance penalty in using functions from os
instead of directly from the OS dependent built-in module, so there
should be no reason not to use os!
The os module contains many functions and data values.
The items below and in the following sub-sections are all available
directly from the os module.
This exception is raised when a function returns a
system-related error (e.g., not for illegal argument types). This is
also known as the built-in exception OSError. The
accompanying value is a pair containing the numeric error code from
errno and the corresponding string, as would be printed by the
C function perror(). See the module
errno, which contains names for the
error codes defined by the underlying operating system.
When exceptions are classes, this exception carries two attributes,
errno and strerror. The first holds the value of
the C errno variable, and the latter holds the corresponding
error message from strerror(). For exceptions that
involve a file system path (e.g. chdir() or
unlink()), the exception instance will contain a third
attribute, filename, which is the file name passed to the
function.
When exceptions are strings, the string for the exception is
'OSError'.
The corresponding OS dependent standard module for pathname
operations, e.g., posixpath or macpath. Thus, given
the proper imports, os.path.split(file) is equivalent to but
more portable than posixpath.split(file). Note that this
is also a valid module: it may be imported directly as
os.path.