os.geteuid() Return the current process’s effective user id. Availability: Unix.

os.getenvb(key, default=None) Return the value of the environment variable key if it exists, or default if it doesn’t. key, default and the result are bytes. Availability: most flavors of Unix. New in version 3.2.

os.getenv(key, default=None) Return the value of the environment variable key if it exists, or default if it doesn’t. key, default and the result are str. On Unix, keys and values are decoded with sys.getfilesystemencoding() and 'surrogateescape' error handler. Use os.getenvb() if you would like to use a different encoding. Availability: most flavors of Unix, Windows.

os.getegid() Return the effective group id of the current process. This corresponds to the “set id” bit on the file being executed in the current process. Availability: Unix.

os.getcwdb() Return a bytestring representing the current working directory.

os.getcwd() Return a string representing the current working directory.

os.fwalk(top='.', topdown=True, onerror=None, *, follow_symlinks=False, dir_fd=None) This behaves exactly like walk(), except that it yields a 4-tuple (dirpath, dirnames, filenames, dirfd), and it supports dir_fd. dirpath, dirnames and filenames are identical to walk() output, and dirfd is a file descriptor referring to the directory dirpath. This function always supports paths relative to directory descriptors and not following symlinks. Note however that, unlike other functions, the fwalk(

os.ftruncate(fd, length) Truncate the file corresponding to file descriptor fd, so that it is at most length bytes in size. As of Python 3.3, this is equivalent to os.truncate(fd, length). Availability: Unix, Windows. Changed in version 3.5: Added support for Windows

os.fsync(fd) Force write of file with filedescriptor fd to disk. On Unix, this calls the native fsync() function; on Windows, the MS _commit() function. If you’re starting with a buffered Python file object f, first do f.flush(), and then do os.fsync(f.fileno()), to ensure that all internal buffers associated with f are written to disk. Availability: Unix, Windows.

os.fstatvfs(fd) Return information about the filesystem containing the file associated with file descriptor fd, like statvfs(). As of Python 3.3, this is equivalent to os.statvfs(fd). Availability: Unix.