Concept: The os module

Function / attribute	Description	Example
os.getcwd()	Returns the current working directory.	os.getcwd() → '/home/admin'
os.chdir(path)	Changes the current working directory.	os.chdir("/var/log")
os.listdir(path)	Returns a list with the names of the entries in a directory.	os.listdir("/etc")
os.walk(path)	Walks a directory tree recursively, yielding (dirpath, dirnames, filenames).	for root, dirs, files in os.walk("/var/log"):
os.mkdir(path)	Creates a single directory.	os.mkdir("backups")
os.makedirs(path, exist_ok=True)	Creates a directory and all missing parent directories.	os.makedirs("/tmp/a/b/c", exist_ok=True)
os.remove(path)	Deletes a file.	os.remove("old.log")
os.rmdir(path)	Deletes an empty directory.	os.rmdir("backups")
os.rename(src, dst)	Renames or moves a file or directory.	os.rename("app.log", "app.log.1")
os.chmod(path, mode)	Changes the permissions of a file (Unix-style octal mode).	os.chmod("script.py", 0o755)
os.stat(path)	Returns file metadata (size, owner, timestamps, permissions, ...).	os.stat("app.log").st_size
os.path.exists(path)	Checks whether a file or directory exists.	os.path.exists("/etc/hosts") → True
os.path.isfile(path)	Checks whether a path is an existing file.	os.path.isfile("/etc/hosts") → True
os.path.isdir(path)	Checks whether a path is an existing directory.	os.path.isdir("/etc") → True
os.path.abspath(path)	Converts a relative path to an absolute path.	os.path.abspath("script.py") → '/home/admin/script.py'
os.path.join(a, b, ...)	Joins path components using the correct separator for the OS.	os.path.join("/var", "log", "syslog")
os.path.basename(path)	Returns the last component of a path (the file name).	os.path.basename("/var/log/syslog") → 'syslog'
os.path.dirname(path)	Returns the directory part of a path.	os.path.dirname("/var/log/syslog") → '/var/log'
os.path.getsize(path)	Returns the size of a file in bytes.	os.path.getsize("app.log") → 20480
os.environ	Dictionary-like object containing the environment variables.	os.environ["PATH"]
os.getenv(key, default=None)	Returns an environment variable, or the default if it doesn't exist.	os.getenv("HOME", "/tmp")
os.getpid()	Returns the process ID of the running script.	os.getpid() → 48213
os.cpu_count()	Returns the number of logical CPUs.	os.cpu_count() → 8
os.name	Name of the OS family: 'posix' (Linux/macOS) or 'nt' (Windows).	if os.name == "nt":
os.sep	The path separator of the OS: '/' or '\'.	os.sep → '/'
os.uname()	Returns system information (hostname, kernel release, architecture). Unix only.	os.uname().nodename → 'web01'
os.geteuid()	Returns the effective user ID; 0 means root. Unix only.	if os.geteuid() != 0: