122. Using os for OS-level Operations

Here are 10 Python code snippets demonstrating how to interact with the operating system using the functions from the os module:

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1. Checking if a File or Directory Exists

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import os

# Check if a file exists
file_path = 'test_file.txt'
if os.path.exists(file_path):
    print(f"{file_path} exists.")
else:
    print(f"{file_path} does not exist.")

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2. Creating a Directory

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import os

# Create a directory
directory_path = 'my_folder'
if not os.path.exists(directory_path):
    os.mkdir(directory_path)
    print(f"Directory '{directory_path}' created.")
else:
    print(f"Directory '{directory_path}' already exists.")

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3. Changing the Current Working Directory

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import os

# Change the current working directory
new_directory = '/home/user/Documents'
os.chdir(new_directory)
print(f"Current working directory is now: {os.getcwd()}")

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4. Listing Files in a Directory

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import os

# List all files in a directory
directory_path = '.'
files = os.listdir(directory_path)
print(f"Files in {directory_path}: {files}")

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5. Removing a File

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import os

# Remove a file
file_path = 'test_file.txt'
if os.path.exists(file_path):
    os.remove(file_path)
    print(f"File {file_path} removed.")
else:
    print(f"File {file_path} does not exist.")

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6. Removing a Directory

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import os

# Remove a directory
directory_path = 'my_folder'
if os.path.exists(directory_path):
    os.rmdir(directory_path)
    print(f"Directory {directory_path} removed.")
else:
    print(f"Directory {directory_path} does not exist.")

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7. Getting Environment Variables

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import os

# Get an environment variable
user_home = os.getenv('HOME')
print(f"User's home directory: {user_home}")

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8. Getting File Information

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import os

# Get file information
file_path = 'test_file.txt'
if os.path.exists(file_path):
    file_info = os.stat(file_path)
    print(f"File size: {file_info.st_size} bytes")
    print(f"File created: {file_info.st_ctime}")
else:
    print(f"File {file_path} does not exist.")

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9. Executing Shell Commands

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import os

# Run a shell command
command = 'ls -l'
result = os.system(command)
print(f"Command executed with exit code: {result}")

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10. Renaming a File

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import os

# Rename a file
old_name = 'old_file.txt'
new_name = 'new_file.txt'
if os.path.exists(old_name):
    os.rename(old_name, new_name)
    print(f"Renamed {old_name} to {new_name}.")
else:
    print(f"{old_name} does not exist.")

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These snippets demonstrate how to use the os module to perform various operating system-level operations, including file management, directory handling, environment interaction, and executing system commands.