如何用Python递归移除目录及所有子目录、文件的写入权限？

Got it, you want to replicate the Bash command chmod -R a-w $path in Python—removing write permissions for all users (owner, group, others) across a directory and every file/subdirectory inside it. Since Python's built-in os.chmod doesn't have a recursive=True parameter, we need to handle the directory traversal ourselves. Here are two clean ways to do this:

Method 1: Using os.walk (classic approach) #

This uses the standard os module to walk through every file and directory, adjusting permissions one by one:

import os

def remove_recursive_write_permissions(path):
    # Traverse the directory tree top-down
    for root, dirs, files in os.walk(path):
        # Update permissions for subdirectories first
        for dir_name in dirs:
            dir_path = os.path.join(root, dir_name)
            # Get the current permission mode
            current_mode = os.stat(dir_path).st_mode
            # Remove write permissions for all users (a-w = ~0o222 in octal)
            new_mode = current_mode & ~0o222
            os.chmod(dir_path, new_mode)
        
        # Then update permissions for files
        for file_name in files:
            file_path = os.path.join(root, file_name)
            current_mode = os.stat(file_path).st_mode
            new_mode = current_mode & ~0o222
            os.chmod(file_path, new_mode)

# Example usage
remove_recursive_write_permissions("/your/target/directory")

How it works: #

• os.walk(path) iterates through every directory and file under the target path.
• os.stat(item).st_mode gets the current permission bits of the file/directory.
• The bitwise operation & ~0o222 clears the write bits for all users:
  • 0o222 is octal for owner write (200), group write (020), others write (002)
  • ~0o222 flips those bits to 1s, and ANDing with the current mode turns off those write permissions.

Method 2: Using pathlib (modern Python 3.4+) #

If you prefer a more object-oriented approach, pathlib makes this cleaner:

from pathlib import Path

def remove_recursive_write_permissions(path):
    target_dir = Path(path)
    # Recursively match all files and subdirectories (excludes the root itself)
    for item in target_dir.rglob("*"):
        current_mode = item.stat().st_mode
        item.chmod(current_mode & ~0o222)
    
    # Don't forget to update the root directory's permissions too!
    root_mode = target_dir.stat().st_mode
    target_dir.chmod(root_mode & ~0o222)

# Example usage
remove_recursive_write_permissions("/your/target/directory")

Note: #

rglob("*") matches every item inside the target directory, but not the directory itself—hence the separate step to update the root's permissions.

Adding Error Handling #

If you're dealing with a directory where you might not have full permissions, add try-except blocks to avoid crashes:

from pathlib import Path
import traceback

def remove_recursive_write_permissions(path):
    target_dir = Path(path)
    for item in target_dir.rglob("*"):
        try:
            current_mode = item.stat().st_mode
            item.chmod(current_mode & ~0o222)
        except PermissionError:
            print(f"Skip {item}: Insufficient permissions to modify")
        except Exception as e:
            print(f"Unexpected error processing {item}: {str(e)}")
            traceback.print_exc()
    
    # Handle root directory
    try:
        root_mode = target_dir.stat().st_mode
        target_dir.chmod(root_mode & ~0o222)
    except PermissionError:
        print(f"Skip root directory {target_dir}: Insufficient permissions")
    except Exception as e:
        print(f"Unexpected error processing root {target_dir}: {str(e)}")
        traceback.print_exc()

Customizing Permissions #

If you don't want to remove write permissions for all users, adjust the octal value:

• Remove only others' write permissions: ~0o002
• Remove group and others' write permissions: ~0o022
• Remove only owner's write permissions: ~0o200

内容的提问来源于stack exchange，提问作者wotanii