os.listdir(path='.') Return a list containing the names of the entries in the directory given by path. The list is in arbitrary order, and does not include the special entries '.' and '..' even if they are present in the directory. path may be either of type str or of type bytes. If path is of type bytes, the filenames returned will also be of type bytes; in all other circumstances, they will be of type str. This function can also support specifying a file descriptor; the file descriptor mus

os.link(src, dst, *, src_dir_fd=None, dst_dir_fd=None, follow_symlinks=True) Create a hard link pointing to src named dst. This function can support specifying src_dir_fd and/or dst_dir_fd to supply paths relative to directory descriptors, and not following symlinks. Availability: Unix, Windows. Changed in version 3.2: Added Windows support. New in version 3.3: Added the src_dir_fd, dst_dir_fd, and follow_symlinks arguments.

os.linesep The string used to separate (or, rather, terminate) lines on the current platform. This may be a single character, such as '\n' for POSIX, or multiple characters, for example, '\r\n' for Windows. Do not use os.linesep as a line terminator when writing files opened in text mode (the default); use a single '\n' instead, on all platforms.

os.lchown(path, uid, gid) Change the owner and group id of path to the numeric uid and gid. This function will not follow symbolic links. As of Python 3.3, this is equivalent to os.chown(path, uid, gid, follow_symlinks=False). Availability: Unix.

os.lchmod(path, mode) Change the mode of path to the numeric mode. If path is a symlink, this affects the symlink rather than the target. See the docs for chmod() for possible values of mode. As of Python 3.3, this is equivalent to os.chmod(path, mode, follow_symlinks=False). Availability: Unix.

os.lchflags(path, flags) Set the flags of path to the numeric flags, like chflags(), but do not follow symbolic links. As of Python 3.3, this is equivalent to os.chflags(path, flags, follow_symlinks=False). Availability: Unix.

os.killpg(pgid, sig) Send the signal sig to the process group pgid. Availability: Unix.

os.kill(pid, sig) Send signal sig to the process pid. Constants for the specific signals available on the host platform are defined in the signal module. Windows: The signal.CTRL_C_EVENT and signal.CTRL_BREAK_EVENT signals are special signals which can only be sent to console processes which share a common console window, e.g., some subprocesses. Any other value for sig will cause the process to be unconditionally killed by the TerminateProcess API, and the exit code will be set to sig. The

os.isatty(fd) Return True if the file descriptor fd is open and connected to a tty(-like) device, else False.

os.initgroups(username, gid) Call the system initgroups() to initialize the group access list with all of the groups of which the specified username is a member, plus the specified group id. Availability: Unix. New in version 3.2.