Essential Python OS & File Operations for Automation

With the rapid growth of the information age and the increasing integration of the Internet into daily life, the role of IT operations has become more critical. Traditional manual operations can no longer meet business demands, so automation—built on standardized, procedural foundations—is essential for improving efficiency, reducing costs, and enhancing service quality.

Common os module functions

os.getcwd()

– Get the current working directory. os.listdir(path) – List all files and directories in the specified path. os.remove(path) – Delete a single file. os.removedirs(path) – Remove multiple directories (use with caution). os.path.isfile(path) – Check if a path points to a file. os.path.isdir(path) – Check if a path points to a directory. os.path.isabs(path) – Determine whether a path is absolute. os.path.exists(path) – Verify that a path exists. os.path.split(path) – Split a path into directory and file name. os.path.splitext(path) – Separate the file name from its extension. os.path.dirname(path) – Get the directory component of a path. os.path.basename(path) – Get the file name component of a path. os.system(command) – Execute a shell command. os.getenv(key) / os.putenv(key, value) – Read and set environment variables. os.linesep – Platform-specific line separator (e.g., "\r\n" on Windows). os.name – Identify the operating system ("nt" for Windows, "posix" for Unix/Linux). os.rename(old, new) – Rename a file or directory. os.makedirs(path) – Create nested directories. os.mkdir(path) – Create a single directory. os.stat(path) – Retrieve file attributes. os.chmod(path, mode) – Change file permissions. os.exit() – Terminate the current process (Python 2.4+). os.path.getsize(path) – Get the size of a file.

File handling with open()

Modes: w (write), a (append), r+ (read/write), w+ (read/write, truncates), a+ (read/write, appends), rb, wb, ab, rb+, wb+, ab+ (binary variants). fp.read([size]) – Read up to *size* bytes. fp.readline([size]) – Read a single line, optionally limited by *size*. fp.readlines() – Read all lines into a list. fp.write(str) – Write a string (no automatic newline). fp.writelines(seq) – Write an iterable of strings. fp.close() – Close the file. fp.flush() – Flush the internal buffer to disk. fp.fileno() – Return the file descriptor. fp.isatty() – Check if the file is a terminal device. fp.tell() – Get the current file pointer position. fp.seek(offset, whence=0) – Move the file pointer; *whence* = 0 (start), 1 (current), 2 (end). fp.truncate([size]) – Truncate the file to *size* bytes (default current position).

Directory and file operations with shutil

shutil.copyfile(src, dst)

– Copy a file. shutil.copy(src, dst) – Copy a file; *dst* can be a directory. shutil.copytree(src, dst) – Recursively copy an entire directory tree (destination must not exist). shutil.move(src, dst) – Move a file or directory. os.rmdir(path) – Remove an empty directory. shutil.rmtree(path) – Remove a directory and all its contents. os.chdir(path) – Change the current working directory.

Key file‑pointer methods explained

seek(offset, whence)

– Move the pointer; *whence* = 0 (from start), 1 (from current), 2 (from end). tell() – Return the current pointer offset. truncate(n) – Shorten the file to *n* bytes; if *n* exceeds the file size, behavior varies by OS. readline(n) – Read a line up to *n* bytes; if *n* is omitted, reads the full line. readlines() – Read all lines into a list. read() – Read the entire file content.

Practical example demonstrating file pointer behavior

fso = open("f:\\a.txt", 'w+')
print fso.tell()          # 0 – file is empty after opening with w+

fso.write("abcde
")      # Write 7 bytes (including 
)
print fso.tell()          # 7

fso.write("fghwm")        # Write 5 more bytes
print fso.tell()          # 12

fso.seek(1, 0)            # Move to offset 1 from start
print fso.tell()          # 1

print fso.readline()     # Reads from position 1, outputs "bcde"
print fso.tell()          # 7 – after reading the line

fso.truncate(8)            # Truncate to 8 bytes, resulting content "abcde
f"
print fso.tell()          # Still 7 (position unchanged by truncate)
print fso.readline()     # Reads from position 8, outputs "f"

This collection of functions and examples equips operations engineers with the essential Python tools to script routine tasks, manipulate files and directories programmatically, and build reliable automation workflows.