Python Standard Library for Linux: File Operations, Process Management, Networking, System Info, Time, Logging, Monitoring, Compression, and Environment Variables

1. File and Directory Operations

1.1 os

Provides OS interfaces for file and directory operations.

import os
# Get current working directory
print(os.getcwd())  # output current directory
# Change working directory
os.chdir('/path/to/new/directory')
print(os.getcwd())  # output new directory
# Create directory
os.mkdir('/path/to/new/directory')
# Remove directory
os.rmdir('/path/to/new/directory')
# List directory contents
files = os.listdir('/path/to/directory')
print(files)  # output contents
# Get file size
size = os.path.getsize('/path/to/file')
print(size)  # output size

1.2 os.path

Provides path‑related operations.

import os.path
# Join paths
path = os.path.join('/home/user', 'documents', 'file.txt')
print(path)  # /home/user/documents/file.txt
# Split path
dir, file = os.path.split('/home/user/documents/file.txt')
print(dir)   # /home/user/documents
print(file)  # file.txt
# Get file extension
ext = os.path.splitext('/home/user/documents/file.txt')[1]
print(ext)   # .txt
# Check existence
exists = os.path.exists('/path/to/file')
print(exists)  # True or False

1.3 shutil

Provides high‑level file operations such as copy, move, and removal.

import shutil
# Copy file
shutil.copy('/path/to/source/file', '/path/to/destination/file')
# Move file
shutil.move('/path/to/source/file', '/path/to/destination/file')
# Delete file
os.remove('/path/to/file')
# Delete directory tree
shutil.rmtree('/path/to/directory')

2. Process Management

2.1 subprocess

Used to create child processes and execute external commands.

import subprocess
# Run external command and capture output
result = subprocess.run(['ls', '-l'], capture_output=True, text=True)
print(result.stdout)  # command output
# Synchronous command
subprocess.run(['echo', 'Hello, world!'])
# Asynchronous command
process = subprocess.Popen(['sleep', '2'])
process.wait()  # wait for completion

3. Network Communication

3.1 socket

Creates network sockets for TCP/IP communication.

import socket
# Create TCP server socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(('localhost', 12345))
server_socket.listen(5)
# Accept client connection
client_socket, address = server_socket.accept()
print(f"Connected by {address}")
# Receive data
data = client_socket.recv(1024)
print(f"Received: {data.decode()}")
# Send data
client_socket.sendall(b'Hello, client!')
# Close connections
client_socket.close()
server_socket.close()

4. System Information

4.1 platform

Provides platform‑specific information.

import platform
print(platform.system())   # e.g., Linux
print(platform.release())  # kernel release
print(platform.version())  # full version string
print(platform.machine())  # hardware architecture

4.2 psutil

Provides process and system utilization data.

import psutil
# CPU usage
print(psutil.cpu_percent(interval=1))
# Memory usage
mem_info = psutil.virtual_memory()
print(mem_info.percent)
# Disk usage
disk_info = psutil.disk_usage('/')
print(disk_info.percent)
# Network I/O
net_info = psutil.net_io_counters()
print(net_info.bytes_sent)
print(net_info.bytes_recv)

5. Time and Date

5.1 datetime

Operations for dates and times.

import datetime
now = datetime.datetime.now()
print(now)  # current datetime
formatted = now.strftime('%Y-%m-%d %H:%M:%S')
print(formatted)  # formatted string
parsed = datetime.datetime.strptime('2023-10-01 12:34:56', '%Y-%m-%d %H:%M:%S')
print(parsed)

5.2 time

Provides time‑related functions.

import time
timestamp = time.time()
print(timestamp)  # epoch seconds
time.sleep(2)  # pause 2 seconds
formatted_time = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime())
print(formatted_time)

6. Logging

Provides logging capabilities.

import logging
logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s - %(levelname)s - %(message)s',
                    filename='app.log',
                    filemode='w')
logging.debug('This is a debug message')
logging.info('This is an info message')
logging.warning('This is a warning message')
logging.error('This is an error message')
logging.critical('This is a critical message')

7. File Monitoring

7.1 watchdog

Monitors file‑system events.

from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

class MyHandler(FileSystemEventHandler):
    def on_modified(self, event):
        print(f"Event type: {event.event_type}  path : {event.src_path}")

if __name__ == "__main__":
    event_handler = MyHandler()
    observer = Observer()
    observer.schedule(event_handler, path='/path/to/watch', recursive=True)
    observer.start()
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()

8. File Compression

8.1 gzip

Provides GZIP compression.

import gzip
# Compress file
with gzip.open('file.gz', 'wb') as f:
    f.write(b'Hello, world!')
# Decompress file
with gzip.open('file.gz', 'rb') as f:
    content = f.read()
    print(content)  # b'Hello, world!'

9. System Environment Variables

9.1 os.environ

Accesses and modifies environment variables.

import os
# Get environment variable
print(os.environ['PATH'])
# Set environment variable
os.environ['MY_VAR'] = 'value'
# Delete environment variable
del os.environ['MY_VAR']

Conclusion

Through the above sections we have detailed Python's standard libraries related to Linux, including file and directory handling, process management, network communication, system information, date and time, logging, file monitoring, compression, and environment variables, enabling more efficient Python development on Linux systems.